Interventions for replacing missing teeth: augmentation procedures of the maxillary sinus
Abstract
Background
Insufficient bone volume is a common problem encountered in the rehabilitation of the edentulous posterior maxillae with implant‐supported prostheses. Bone volume is limited by the presence of the maxillary sinus together with loss of alveolar bone height. Sinus lift procedures increase bone volume by augmenting the sinus cavity with autogenous bone or commercially available biomaterials, or both. This is an update of a Cochrane review first published in 2010.
Objectives
To assess the beneficial or harmful effects of bone augmentation compared to no augmentation when undertaking a sinus lift procedure. Secondly, to compare the benefits and harms of different maxillary sinus lift techniques for dental implant rehabilitation.
Search methods
We searched the Cochrane Oral Health Group's Trials Register (to 17 January 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 12), MEDLINE via OVID (1946 to 17 January 2014) and EMBASE via OVID (1980 to 17 January 2014). There were no language or date restrictions on the searches of the electronic databases.
Selection criteria
Randomised controlled trials (RCTs) of different techniques and materials for augmenting the maxillary sinus for rehabilitation with dental implants that report the outcome of implant success or failure at least to four months after initial loading.
Data collection and analysis
Screening of eligible studies, assessment of the risk of bias of the trials, and data extraction were conducted independently and in duplicate. Authors were contacted for any missing information. Results were expressed using fixed‐effect models as there were either less than four studies or we used Peto odds ratios (ORs) for dichotomous data when there were zero cells in either the treatment or control or both arms and the number of trials was small. The statistical unit of the analysis was the patient.
Main results
Eighteen RCTs out of 64 potentially eligible study reports met the inclusion criteria. They compared undertaking a sinus lift with not doing so, and the use of different sinus lift techniques. There were 650 patients providing data for the outcomes evaluated. Five studies were assessed as low risk of bias, 11 were assessed as high risk of bias, and in two the risk was unclear.
Sinus lift versus no sinus lift
Four trials of moderate quality (three trials at low and one at high risk of bias) with 102 participants evaluated short implants (5 to 8.5 mm long) as an alternative to sinus lift in bone with residual height between 4 and 9 mm. One year after loading there was insufficient evidence to claim differences between the two procedures for prosthesis failure (OR (Peto) 0.37, 95% confidence interval (CI) 0.05 to 2.68; three trials) or implant failure (OR (Peto) 0.44, 95% CI 0.10 to 1.99; four trials). There was however an increase in complications at treated sites when undertaking the sinus lift (OR (Peto) 4.77, 95% CI 1.79 to 12.71, P value = 0.002; four trials).
Different sinus lift techniques
Fourteen trials with 548 participants compared different sinus lift techniques. Only three comparisons included more than one trial (two trials for each). These were bone graft versus no bone graft, autogenous bone versus bone substitute, bone graft with or without platelet‐rich plasma (PRP). There was insufficient evidence to claim a benefit for any of these techniques for the primary outcomes of prosthesis and implant failure. For the other reported outcomes, in a single study at high risk of bias, only bone gain was greater for the bone graft site than the site without a graft six months after augmentation, however this was not significant at 18 or 30 months.
The other comparisons with single studies were rotary versus piezosurgery to open a lateral sinus window, two different bone substitutes, use or not of a membrane to seal the lateral window, one‐ versus two‐stage lateral sinus lift, two‐stage granular bone versus one‐stage autogenous bone blocks, and crestal versus lateral sinus lift; two trials compared three different crestal sinus lifting techniques: rotatory versus hand malleting (patients preferred rotatory instruments over hand malleting) and hand versus electric malleting. There was no evidence of a benefit for any sinus lift procedure compared to any other for the primary outcomes prosthesis or implant failure.
Authors' conclusions
There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 8.5 mm) in reducing prosthesis or implant failure up to one year after loading. However, there are more complications at sites treated with sinus lift procedures. Many trials compared different sinus lift procedures and none of these indicated that one procedure reduced prosthetic or implant failures when compared to the other. Based on low quality evidence, patients may prefer rotary instruments over hand malleting for crestal sinus lift.
Plain language summary
Interventions for replacing missing teeth: increasing bone thickness at the base of the natural sinus cavity above the upper jaw (maxillary sinus) to augment the maxillary sinus to enable implants
Review question
This review, carried out by the Cochrane Oral Health Group, seeks to determine whether and when it is necessary to increase the thickness of the bone layer at the base of the natural sinus cavity (maxillary sinus) that lies above the upper jaw in order to successfully insert dental implants onto which artificial teeth will be anchored. Also, to find the most effective techniques for doing this.
Background
Missing teeth may cause problems with eating and speaking, and affect how someone looks. Traditionally they have been replaced by loose false teeth (dentures) or bridges fixed between other teeth. Dental implants offer an alternative way of replacing teeth. Implants look like screws; they are made from materials such as titanium, which can fuse with the bone they are placed in (osseointegration) offering a stable base for artificial teeth to be fixed to. However, there needs to be enough depth of bone to successfully insert the implants. Bone thickness towards the back of the upper jaw can sometimes be too thin because of the natural sinus cavity (maxillary sinus) that lies above it. The cavity can also sometimes become larger following tooth loss.
Where the bone is too thin, there are a number of techniques that are used to create a thicker layer of bone at the base of the sinus cavity which are generally known as 'sinus lift' procedures. These methods involve using either bone taken from the patient (autogenous bone) or other materials known as biomaterials, a combination of the two, or sometimes simply using a blood clot as a base for the body to naturally form additional bone.
An alternative to a sinus lift is to use, where possible, short implants (4 to 8.5 mm long).
Study characteristics
The evidence on which this review is based is correct as of 17 January 2014. Eighteen trials with 650 participants were included. Four of the trials, with a total of 102 participants, compared implant‐supported prostheses using a sinus lift with prostheses on short implants (5 to 8.5 mm long) without sinus lift. The remaining 14 trials with a total of 548 participants compared different sinus lift techniques.
Key results
There is not enough evidence to show whether sinus lift techniques are more or less successful in reducing the number of failures of dental prostheses (artificial teeth) or dental implants when compared to simply using short implants, up to one year after loading.
However, there is limited evidence that there are fewer complications when short implants are used without surgical lifts. Complications include sinusitis, infection and bleeding, and when bone grafts are taken from the patient complications can also include nerve injury, problems with walking and infection.
Quality of the evidence
The quality of the evidence for whether or not to use a sinus lift procedure was moderate. The evidence for the 14 comparisons of different sinus lift procedures was based on a maximum of two comparisons for each comparison and was low.
Authors' conclusions
Summary of findings
| Long implants with augmentation versus short implants without augmentation for replacing missing teeth: augmentation procedures of the maxillary sinus | ||||||
| Patient or population: patients with replacing missing teeth | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect | No of participants | Quality of the evidence | Comments | |
| Assumed risk | Corresponding risk | |||||
| Short implants | Long implants with sinus lift | |||||
| Prosthesis failures | Study population | OR 0.37 | 109 | ⊕⊕⊕⊝ | ||
| 55 per 1000 | 21 per 1000 | |||||
| Moderate | ||||||
| 50 per 1000 | 19 per 1000 | |||||
| Implant failures | Study population | OR 0.44 | 137 | ⊕⊕⊕⊝ | ||
| 71 per 1000 | 33 per 1000 | |||||
| Moderate | ||||||
| 50 per 1000 | 23 per 1000 | |||||
| Complications | Study population | OR 4.77 | 137 | ⊕⊕⊝⊝ | ||
| 43 per 1000 | 176 per 1000 | |||||
| Moderate | ||||||
| 50 per 1000 | 201 per 1000 | |||||
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI) | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded for imprecision (small number of events) | ||||||
| Comparison between different sinus lift procedures | |
| Patient or population: patients with insufficient bone below maxillary sinus Settings: dental practice Intervention: sinus lift procedure Comparison: sinus lift procedure | |
| Outcomes | Comments |
| Prosthesis failures (at 5 months to 5 years) | Data for prosthetic failures were present for 5 comparisons (all only including 1 small study). There is insufficient evidence to conclude that 1 sinus lift procedure leads to fewer prosthetic failures than another. The comparisons for this outcome were: bone graft versus no bone graft, 2 different bone substitutes, 1‐ versus 2‐stage lateral sinus lift, 2‐stage granular bone versus 1‐stage autogenous bone blocks, and crestal versus lateral sinus lift |
| Implant failures (at 5 months to 5 years) | Data for implant failures were present for 8 comparisons (including 1 or 2 small studies). There is insufficient evidence to conclude that 1 sinus lift procedure leads to fewer implant failures than another. The comparisons for this outcome were: bone graft versus no bone graft, autogenous bone versus bone substitute, bone graft with or without platelet‐rich plasma (PRP), 2 different bone substitutes, 1‐ versus 2‐stage lateral sinus lift, 2‐stage granular bone versus 1‐stage autogenous bone blocks, crestal versus lateral sinus lift, and hand versus electric malleting for crestal sinus lifting |
Background
Description of the condition
Missing teeth may result in a functional and aesthetic deficit and have traditionally been replaced with dentures or fixed prostheses. Dental implants offer an alternative; they are inserted into the jawbones and used to support dental prostheses. Dental implants rely on the maintenance of a direct structural and functional connection between living bone and the implant surface. This is termed osseointegration and was first described by Brånemark (Brånemark 1977). Osseointegration has undoubtedly been one of the most significant scientific breakthroughs in dentistry over the past 50 years.
Insufficient bone volume is a common problem encountered in the rehabilitation of the edentulous posterior maxilla with implant‐supported prostheses. The bone available for implant placement may be limited by the presence of the maxillary sinus together with loss of alveolar bone height. Bone volume may be increased by augmentation. Commonly the sinus cavity is augmented with autogenous bone or biomaterials, or both. Procedures are variously described in the literature as sinus lift, sinus augmentation, sinus floor elevation or augmentation of atrophic maxillary sinus.
Implant placement may be combined with sinus augmentation as a 'one‐stage' technique. Alternatively sinus augmentation may be carried out some time prior to implant placement as a 'two‐stage' technique, which requires an additional surgical episode.
Description of the intervention
Techniques of sinus augmentation (sinus lift)
Boyne described the surgical technique of retrograde sinus augmentation, where in some cases blade implants were placed (Boyne 1980). The technique required a window to be prepared in the vestibular wall of the sinus, and the sinus epithelium was elevated to create a space into which particulate bone from the iliac crest was placed and allowed to heal for about six months or more before placing the implants.
Tatum described five tissue incisions (crestal, palatal, split thickness palatal, vertical and horizontal vestibular), three types of bone access (crestal, buccal wall and Le Forte I), and the use of autogenous bone, allograft and alloplast. In addition, Tatum described sinus augmentation and implant placement as a one‐stage and a two‐stage technique (Tatum 1986). The technique, known as a lateral window sinus lift, is widely used today and is considered reliable, particularly when autogenous bone is used (Wallace 2003; Del Fabbro 2004).
Summers described a less invasive one‐stage technique for sinus floor elevation with simultaneous implant placement, called the osteotome sinus floor elevation. Summers considered it necessary to have at least 6 mm of residual bone to ensure primary stability of the implant. Concave tipped osteotomes of increasing diameter applied via a crestal approach advanced a mass of bone beyond the level of the original sinus floor, elevating the sinus epithelium. Summers combined this procedure with the addition of a bone graft material (Summers 1994). For cases with less than 6 mm residual bone height, Summers proposed a two‐stage approach. A bone plug is defined with a trephine and displaced superiorly with the use of a broad osteotome. Hydrostatic pressure elevates the mucosal lining of the sinus. The resultant osteotomy is filled with a bone graft material and the implant placed after a period of healing (Summers 1995).
Cosci modified the crestal approach technique utilising an atraumatic lifting drill to reduce the risk of perforation of the mucosa lining of the sinus and using a one‐stage technique with as little as 3 mm of residual bone (Cosci 2000). Bone can be collected with a trephine directly from the osteotomy site, to be used as grafting material; a bone substitute can be used, or the implant tip can hold up the sinus membrane to work as a natural barrier for bone regeneration. While the crestal approach is less invasive, and is a one‐stage technique, there are some disadvantages associated with it. The amount of bone which can be gained using a crestal approach is usually less than that obtained with the lateral window technique, and a minimum of 3 mm crestal bone height is generally recommended to stabilize the implant at placement (Cosci 2000).
In order to obtain simultaneous vertical bone augmentation with a sinus lift procedure, Cannizzaro proposed a technique that is a combination of a sinus lift and an onlay graft. Implants are placed in the ulna and bone blocks containing the implants are retrieved with a trephine, inserted into the sinus via a crestal approach, and left protruding occlusally for some millimetres in order to obtain simultaneous vertical bone gain (Cannizzaro 2007).
Materials used in sinus lift procedures
Autogenous bone has long been considered the gold standard (Palmer 2000). Intra‐oral donor sites (chin and ramus) are convenient but yield limited volume. Extra‐oral donor sites (iliac crest, tibia, ulna, rib and calvarium) increase surgical complexity and are associated with significant (and under‐reported) morbidity and scarring. Therefore, alternative grafting materials (bone substitutes) have been developed.
Allografts consist of 'same species' tissue. Cadaveric bone is harvested and various techniques (freeze drying and irradiation) reduce antigenicity. The grafts are then sterilised and supplied by specially licensed tissue banks.
Xenografts consist of 'different species' tissue. Bovine, swine and equine bone predominate. Complete or partial thermo‐chemical removal of the organic component eventually creates a mineral scaffold with residual collagen, depending on the preparation procedures used (anorganic).
Alloplasts are synthetic bone substitutes. There are many types classified in terms of porosity as dense, macro‐porous, micro‐porous, and either crystalline or amorphous. The structure influences performance. Some examples are beta tri‐calcium phosphate, bio‐active glass, calcium sulphate, etc.
All these graft materials can be delivered in various convenient forms such as bone particles (eventually in streaky gels) or large blocks, can be mixed with autogenous bone, and can be very stable over time or are highly resorbable, depending on their physical characteristics.
Urist discovered that cell‐free, decalcified bone implanted into extra‐skeletal sites stimulated new bone formation (Urist 1965). The biologically active molecules that are responsible belong to the growth factor B family and are called bone morphogenetic proteins (BMPs) (Valentin‐Opran 2002). A number have been discovered and include growth factors, platelet‐rich plasma (PRP) and other molecules. Their use requires a delivery system that mimics the physical properties and release kinetics of bone.
Some authors have proposed sinus augmentation without the use of a graft material, with coagulated blood acting as a scaffold for bone formation. Lundgren proposed maintaining a space by suturing the sinus lining to the lateral wall (Lundgren 2004). The implant apex may be used to support the sinus membrane (Nedir 2006; Hatano 2007; Thor 2007; Sohn 2008; Gabbert 2009; Pjetursson 2009). Some bone regeneration does occur as a result of this procedure though the actual clinical benefit is in doubt since this method was not evaluated against appropriate control procedures.
Alternative techniques to sinus lift
There are some alternative techniques to sinus augmentation that may be possible. Onlay bone grafts may be used for horizontal or vertical augmentation. These procedures are evaluated in another Cochrane systematic review (Esposito 2009).
Implants can also be placed with an angulated direction in order to avoid the maxillary sinus (Aparicio 2001), or even placed trans‐sinus (Maló 2013). These implants are called 'tilted' or 'angulated' implants and they can only be used when anatomical conditions permit.
Zygomatic implants offer an alternative to sinus augmentation. Long implants pass through the sinus (Brånemark 2004) or laterally to the sinus into the zygomatic process and can also be loaded immediately (Davò 2013). Zygomatic implants are evaluated in another Cochrane review (Esposito 2013).
Another interesting and simple alternative to sinus lift procedures is the use of short implants (4 to 8 mm long). Current ongoing research is focused on evaluating short implants placed without augmentation, offering the opportunity of a less complex, cheaper and faster alternative to augmentation. There are few randomised controlled trials evaluating the efficacy of short implants both in upper and lower jaws (Cannizzaro 2009; Felice 2009a; Esposito 2011; Felice 2011; Esposito 2012; Felice 2012).
A review of longitudinal studies suggested a failure rate of approximately 10% for implants 7 mm long (das Neves 2006). However, the design of the studies on which this estimate is based suggests that this figure should be viewed with caution as it may represent a gross underestimation. Nevertheless, these figures suggest that shorter implants may have a poorer prognosis than longer ones. Since it is commonly believed that shorter implants (8 mm or less) have a poorer prognosis than longer implants, clinicians place longer implants if bone allows. When bone height is 4 to 8 mm, clinicians must decide whether to augment or place short implants. It is possible that improved implant surface modifications and designs, together with improved surgical techniques, may shift the balance in favour of short implants when the alternative is a more complex augmentation procedure. No reliable evidence of the superiority of currently available surface modifications or designs has been documented so far (Esposito 2007).
Why it is important to do this review
Insufficient bone volumes are a common problem encountered when replacing missing teeth in the maxilla with implant‐supported prostheses. Bone volumes are limited by the presence of the maxillary sinuses together with loss of alveolar bone height. If effective, sinus lift procedures will increase bone volume by augmenting the sinus cavity with autogenous bone or commercially available biomaterials, or both. This will allow patients who cannot be rehabilitated with conventional implants due to insufficient bone volumes to receive fixed implant‐supported prostheses, improving their quality of life. However, it is still unclear what the minimal bone heights are under which a sinus lift procedure will improve the prognosis of implant‐supported prostheses, and there is the risk that augmenting sinuses that do not require it would increase morbidity with no actual benefits for the patients. This is an update of a Cochrane review first published in 2010 (Esposito 2010) that originates from a previous larger review evaluating all types of augmentation procedures for dental implant placement (Coulthard 2003; Esposito 2006a; Esposito 2008).
Objectives
To assess the beneficial or harmful effects of bone augmentation compared to no augmentation when undertaking a sinus lift procedure. Secondly, to compare the benefits and harms of different maxillary sinus lift techniques for dental implant rehabilitation.
Methods
Criteria for considering studies for this review
Types of studies
Randomised controlled trials (RCTs) including split‐mouth studies.
Types of participants
Patients with missing teeth and an atrophic posterior maxilla who may require augmentation of the maxillary sinus prior to or at placement of dental implants.
Types of interventions
Any bone augmentation technique, active agent (such as bone morphogenetic proteins, platelet‐rich plasma, stem cells) or biomaterials used together with osseointegrated, root‐formed dental implants. When comparing sinus lift procedures with no augmentation procedures, implants can have different dimensions (for instance be shorter and wider), can be placed in an angulated direction, and can be trans‐sinus. The use of zygomatic implants is evaluated in another Cochrane review (Esposito 2013).
For trials to be considered in this review, implants had to be placed and the success or failure of the implant therapy had to be reported at least at the endpoint of four months after initial loading of the implant‐supported prostheses. The following time points were considered: between four months to one year, three and five years after loading.
Types of outcome measures
Primary outcomes
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Prosthesis failure: planned prosthesis that could not be placed due to implant failure(s), loss of the prosthesis secondary to implant failure(s), and any replacement of prosthesis.
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Implant failure: implant mobility and removal of stable implants dictated by progressive marginal bone loss or infection (biological failures) and any mechanical complication such us implant fractures or platform deformations rendering the implant not usable (mechanical failure). Biological failures were grouped as early (failure to establish osseointegration) and late failures (failure to maintain the established osseointegration). Failures that occurred before prosthesis placement were considered early failures. Implant mobility could be assessed manually or with instruments such as the Periotest (Siemens AG, Benshein, Germany) or resonance frequency (Osstell, Integration Diagnostics, Göteborg, Sweden).
Secondary outcomes
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Augmentation procedure failure: failure of the augmentation procedure, not affecting the success of the implant.
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Complications at treated sites (e.g. sinusitis, infection, haemorrhage, etc.) including, when appropriate, complications at bone donor sites (e.g. nerve injury, gait disturbance, infection, etc.).
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Patient satisfaction.
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Patient preference (only in split‐mouth trials).
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Bone gain expressed in millimetres or as a percentage.
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Duration of the treatment time starting from the first intervention to the functional loading of the implants.
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Treatment costs.
Trials evaluating only histological outcomes were not considered in this review.
Search methods for identification of studies
For the identification of studies to be included or considered for this review, detailed search strategies were developed for each database searched. These were based on the search strategy developed for MEDLINE (OVID) but revised appropriately for each database. The search strategy used a combination of controlled vocabulary and free text terms and was run with the Cochrane Highly Sensitive Search Strategy (CHSSS) for identifying randomised trials in MEDLINE: sensitivity maximising version (2009 revision) as referenced in Chapter 6.4.11.1 and detailed in box 6.4.c of the Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 (Higgins 2011). Details of the MEDLINE search are provided in Appendix 1.
Searched databases
We searched the following electronic databases:
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the Cochrane Oral Health Group's Trials Register (17 January 2014) (Appendix 2);
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the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 12) (Appendix 3);
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MEDLINE via OVID (1946 to 17 January 2014) (Appendix 1);
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EMBASE via OVID (1980 to 17 January 2014) (Appendix 4).
We did not place any restrictions on language or date of publication when searching the electronic databases.
Unpublished studies
We wrote to all the authors of the identified RCTs, checked the bibliographies of all identified RCTs and relevant review articles, and used personal contacts in an attempt to identify unpublished or ongoing RCTs. In the first version of this review we also wrote to more than 55 oral implant manufacturers and we requested information on trials through an Internet discussion group ([email protected]), however we discontinued these approaches due to poor yield.
Handsearching
Only handsearching done as part of the Cochrane Worldwide Handsearching Programme and uploaded to CENTRAL was included (see the Cochrane Masterlist for details of journal issues searched to date).
Data collection and analysis
Selection of studies
The titles and abstracts (when available) of all reports identified through the electronic searches were scanned independently by two review authors. For studies appearing to meet the inclusion criteria, or for which there were insufficient data in the title and abstract to make a clear decision, the full report was obtained. The full reports obtained from all the electronic and other methods of searching were assessed independently by two review authors to establish whether the studies met the inclusion criteria or not. Disagreements were resolved by discussion. Where resolution was not possible, a third review author was consulted. All studies meeting the inclusion criteria then underwent risk of bias assessment and data extraction. Studies rejected at this or subsequent stages were recorded in the 'Characteristics of excluded studies' table and the reasons for exclusion were recorded.
Data extraction and management
Data were extracted independently by two review authors using specially designed data extraction forms. The data extraction forms were piloted on several papers and modified as required before use. Any disagreement was discussed and a third review author or the Cochrane Oral Health Group consulted where necessary. All authors were contacted for clarification of details or missing information. Data were excluded until further clarification was available if agreement could not be reached.
For each trial the following data were recorded.
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Year of publication, country of origin and source of study funding.
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Details of the participants including demographic characteristics, source of recruitment and criteria for inclusion.
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Details of the type of intervention.
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Details of the outcomes reported, including method of assessment, and time intervals.
Assessment of risk of bias in included studies
An assessment of the risk of bias in the included studies was undertaken following the recommendations as described in Chapter 8 of the Cochrane Handbook for Systematic Reviews of Interventions 5.1.0 (Higgins 2011). Two review authors independently and in duplicate assessed the risk of bias of all included studies. In the case that the paper to be assessed had one or more review authors in the authors list, it was independently evaluated only by those review authors not involved in the trial and by Philip Riley from the Cochrane Oral Health Group editorial base. Any disagreement was discussed and where necessary a third review author was consulted to achieve consensus. Authors were contacted directly for clarification.
A specific tool was adopted for assessing risk of bias in each included study. This comprised a description and a judgement for each entry in a risk of bias table, where each entry addressed a specific feature of the study:
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random sequence generation (selection bias);
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allocation concealment (selection bias);
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blinding (of outcome assessor) (detection bias);
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incomplete outcome data addressed (attrition bias);
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free of selective reporting (reporting bias);
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free of other bias.
The judgement for each entry involved an assessment of: low risk of bias, high risk of bias, or unclear indicating either lack of information or uncertainty over the potential for bias.
After taking into account the additional information provided by the authors of the trials, the overall risk of bias in included studies was assessed. Studies were grouped into the following categories. We assumed that the risk of bias was the same for all outcomes and each study was assessed as follows.
| Risk of bias | Interpretation | Within a study | Across studies |
| Low risk of bias | Plausible bias unlikely to seriously alter the results | Low risk of bias for all key domains | Most information is from studies at low risk of bias |
| Unclear risk of bias | Plausible bias that raises some doubt about the results | Unclear risk of bias for one or more key domains | Most information is from studies at low or unclear risk of bias |
| High risk of bias | Plausible bias that seriously weakens confidence in the results | High risk of bias for one or more key domains | The proportion of information from studies at high risk of bias is sufficient to affect the interpretation of results |
Further quality assessment was carried out to assess sample size calculations, definitions of exclusion and inclusion criteria, and comparability of control and test groups at entry.
Measures of treatment effect
For dichotomous outcomes, the estimate of effect of an intervention was expressed as odds ratios (ORs) together with 95% confidence intervals (CIs). For continuous outcomes, mean differences (MDs) and standard deviations were used to summarise the data for each group with 95% CIs. Appropriate data were extracted from the split‐mouth studies (Lesaffre 2009) and the generic inverse variance method was used to enter the data into Review Manager (RevMan).
Unit of analysis issues
In parallel group studies the statistical unit was the patient and not the augmentation procedure or the implants. In split‐mouth studies the augmentation procedures or the prostheses within each pair were the unit of analysis (Lesaffre 2009).
Dealing with missing data
All authors were contacted to retrieve missing data from trials. Methods for estimating missing standard deviations, in section 7.7.3 of the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011), were used.
Assessment of heterogeneity
The significance of any variations in the estimates of the treatment effects from the different trials was to be assessed by means of Cochran's test for heterogeneity, and heterogeneity would have been considered significant if P value < 0.1. The I2 statistic, which describes the percentage total variation across studies that is due to heterogeneity rather than chance, was used to quantify heterogeneity. with I2 over 50% being considered moderate to high heterogeneity.
Assessment of reporting biases
If there had been sufficient numbers of trials (more than 10) in any meta‐analysis, publication bias would have been assessed according to funnel plot asymmetry (Egger 1997) as described in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011). If asymmetry was identified we would have examined possible causes.
Data synthesis
Meta‐analysis was undertaken where studies of similar comparisons reported the same outcome measures. ORs were combined for dichotomous data, and MDs were to be combined for continuous data, using random‐effects models provided there were more than three studies in the meta‐analysis. When there were up to three studies in the meta‐analyses they were combined using fixed‐effect models. Peto ORs, from fixed‐effect models, were used when there were zero events in the control or treatment arms, or both. Data from split‐mouth studies were to be combined with data from parallel group trials by the method outlined by Elbourne (Elbourne 2002), using the generic inverse variance method in RevMan.
Subgroup analysis and investigation of heterogeneity
Clinical heterogeneity was to be assessed by examining the types of participants and interventions for all outcomes in each study. It was decided not to formulate any hypotheses to be investigated for subgroup analyses since no significant meta‐analysis was expected. However, this may be done in future updates of this review.
Sensitivity analysis
It was planned to undertake sensitivity analyses to examine the effect of the study overall risk of bias assessments on the overall estimates of effect by removing from the analyses studies at unclear and high risk of bias. In addition, the effect on the review's findings of including unpublished literature was also to be examined. There were too few trials to undertake these analyses.
Presentation of main results
We produced summary of findings tables for the main outcomes of this review using GRADEpro software. We assessed the quality of the body of evidence by considering the overall risk of bias of the included studies, the directness of the evidence, the inconsistency of the results, the precision of the estimates, the risk of publication bias and the magnitude of the effect. We categorised the quality of the body of evidence for each of the primary outcomes as high, moderate, low or very low.
Results
Description of studies
Results of the search
The search for this review was part of a wider search for all eligible trials for the series of Cochrane reviews on dental implants. This search is conducted every six months and has so far included about 8700 records.
Included studies
SeeCharacteristics of included studies table.
Eighteen trials were identified to be included in the review (Wannfors 2000; Hallman 2002; Raghoebar 2005; Cannizzaro 2009; Felice 2009a; Felice 2009b; Torres 2009; Checchi 2010; Felice 2011; Crespi 2012: Esposito 2012; Felice 2012; Lindgren 2012; Felice 2013; Merli 2013; Rickert 2013; Si 2013; Torres 2013).
Characteristics of the trial setting and investigators
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Of the 18 included trials, 10 were conducted in Italy (Cannizzaro 2009; Felice 2009a; Felice 2009b; Checchi 2010; Felice 2011; Crespi 2012; Esposito 2012; Felice 2012; Felice 2013; Merli 2013), three in Sweden (Wannfors 2000; Hallman 2002; Lindgren 2012), two in the Netherlands (Raghoebar 2005; Rickert 2013), two in Spain (Torres 2009; Torres 2013), and one in China (Si 2013).
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Seven trials had a parallel group study design (Wannfors 2000; Cannizzaro 2009; Felice 2011; Felice 2012; Felice 2013; Merli 2013; Si 2013), nine trials had a split‐mouth design (Hallman 2002; Raghoebar 2005; Felice 2009a; Felice 2009b; Checchi 2010; Crespi 2012; Esposito 2012; Lindgren 2012; Rickert 2013), one trial had a mixed split‐month and parallel group design (Torres 2009) but only data from its split‐mouth portion could be used in the present review, and another trial had two components: 106 patients were treated according to a parallel group study design and five according to a split‐mouth design (Torres 2013), but only data from its parallel group component could be used in the present review.
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For 11 trials it was declared that support was received from industry directly involved in the product being tested, also in the form of free material (Hallman 2002; Raghoebar 2005; Felice 2009a; Felice 2009b; Checchi 2010; Felice 2011; Esposito 2012; Felice 2012; Lindgren 2012; Felice 2013; Si 2013). The authors of seven trials declared that no support was received from commercial parties whose products were being tested in the trials (Wannfors 2000; Cannizzaro 2009; Torres 2009; Crespi 2012; Merli 2013; Rickert 2013; Torres 2013).
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Eight trials were conducted at university or specialist dental clinics (Wannfors 2000; Hallman 2002; Raghoebar 2005; Felice 2011; Crespi 2012; Lindgren 2012; Rickert 2013; Si 2013), six trials in private practices (Cannizzaro 2009; Felice 2009a; Torres 2009; Checchi 2010; Merli 2013; Torres 2013), and four multicentre trials both in private practices and hospitals (Felice 2009b; Esposito 2012; Felice 2012; Felice 2013).
Inclusion and exclusion criteria
For more details see the Characteristics of included studies table.
Main inclusion criteria
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Severely resorbed maxillae (classes V‐VI according to Cawood 1991) with maxillary sinuses having less than 5 mm in height of residual alveolar bone with reduced stability and retention of upper dentures (Raghoebar 2005; Rickert 2013).
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Less than 5 mm in residual alveolar bone height in the floor of the edentulous sinus (Hallman 2002; Lindgren 2012).
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1 to 3 mm in residual alveolar bone height in the floor of the edentulous sinus (Felice 2013; Merli 2013).
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1 to 5 mm in residual alveolar bone height in the floor of the edentulous sinus (Felice 2009b).
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1 to 7 mm in residual alveolar bone height in the floor of the edentulous sinus (Torres 2009; Torres 2013).
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2 to 7 mm in residual alveolar bone height in the floor of the edentulous sinus (Wannfors 2000).
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2 to 8 mm in residual alveolar bone height in the floor of the edentulous sinus (Si 2013).
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3 to 6 mm in residual alveolar bone height in the floor of the edentulous sinus (Cannizzaro 2009).
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4 to 6 mm in residual alveolar bone height in the floor of the edentulous sinus (Felice 2009a; Felice 2012).
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4 to 7 mm in residual alveolar bone height in the floor of the edentulous sinus (Checchi 2010).
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5 to 7 mm in residual alveolar bone height in the floor of the edentulous sinus (Esposito 2012).
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5 to 9 mm in residual alveolar bone height at implant sites of severely resorbed edentulous maxillas (Felice 2011).
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Insufficient alveolar bone height in the floor of the edentulous sinus (baseline alveolar bone height: 6.71 mm + 1.55 for hand mallet and 6.54 mm + 1.67 for the electric mallet group) (Crespi 2012).
Main exclusion criteria
-
Bone metabolic diseases (Wannfors 2000; Merli 2013; Torres 2013).
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Medications which could interfere with bone metabolism (i.e. corticosteroids, bisphosphonate, etc.) (Wannfors 2000; Cannizzaro 2009; Felice 2009a; Felice 2009b; Checchi 2010; Felice 2011; Esposito 2012; Felice 2012; Felice 2013; Torres 2013).
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Sinusitis (Wannfors 2000; Cannizzaro 2009; Felice 2009a; Felice 2009b; Checchi 2010; Felice 2011; Crespi 2012; Esposito 2012; Felice 2012; Felice 2013; Si 2013).
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History of maxillary sinusitis or sinus surgery (Torres 2009; Crespi 2012; Torres 2013).
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History of reconstructive, pre‐prosthetic surgery or previous oral implantology (Raghoebar 2005; Rickert 2013; Si 2013).
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Edentulous period less than one year (Raghoebar 2005; Rickert 2013).
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Severe systemic disease (ASA III and IV) (Torres 2009; Torres 2013).
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Smoking (Crespi 2012).
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Smoking more than 10 cigarettes per day (Lindgren 2012).
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Smoking more than 20 cigarettes per day (Merli 2013).
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None specified (Hallman 2002).
Sample size
An a priori calculation for the sample size was reported in eight trials (Cannizzaro 2009; Felice 2009a; Checchi 2010; Felice 2011; Esposito 2012; Merli 2013; Si 2013; Torres 2013); however in four trials (Cannizzaro 2009; Felice 2011; Si 2013; Torres 2013) the number of included patients did not reach the calculated sample size and in one trial it was based on inappropriate numbers (Merli 2013).
Baseline comparability between treatment groups
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No apparent major baseline differences (Wannfors 2000; Raghoebar 2005; Felice 2009b; Torres 2009; Checchi 2010; Esposito 2012; Felice 2012; Lindgren 2012; Merli 2013; Si 2013).
-
Unclear whether major baseline differences existed (Hallman 2002; Crespi 2012; Rickert 2013; Torres 2013).
-
The following major baseline differences existed:
-
-
more large diameter implants were placed in the sites treated with 8 mm long implants and crestal sinus lift (Cannizzaro 2009);
-
short 6 mm diameter implants were compared to longer implants with a 4 mm diameter (Felice 2009a);
-
more females and more implants were placed in the augmented group (Felice 2011), however the latter difference was obvious since the resorbed maxillas were grafted and therefore there was more available bone to place more and longer implants;
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more implants placed in the one‐stage group (55 versus 47); more prostheses in the two‐stage group connected to implants placed in non‐augmented bone (12 versus 6); more 3.8 mm small diameter implants used in the one‐stage group (33 versus 20) (Felice 2013).
-
Characteristics of the interventions
The following comparisons were made.
1. Long implants in augmented sinuses versus short implants without augmentation (four trials with 102 participants)
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Four trials evaluating sinus lift versus short implants (Felice 2009a; Felice 2011; Esposito 2012; Felice 2012).
2. Comparing different sinus lift procedures (14 trials with 548 participants)
-
One trial compared the use of rotary instruments or piezosurgery for opening a lateral window into the sinus (Rickert 2013).
-
Two trials compared sinus lift with and without bone grafting (Felice 2009b; Si 2013).
-
Two trials compared sinus list with autogenous bone versus bone substitutes (Hallman 2002; Merli 2013).
-
One trial compared different bone substitutes (Lindgren 2012).
-
Two trials evaluated the additional use of platelet‐rich plasma (PRP) to bone grafts (Raghoebar 2005; Torres 2009).
-
One trial evaluated the use of a resorbable barrier to seal the lateral window (Torres 2013).
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One trial compared one‐stage versus two‐stage augmentation procedures (Felice 2013).
-
One trial compared one‐stage autogenous bone block versus two‐stage lateral window sinus lift (Wannfors 2000).
-
One trial compared lateral versus crestal sinus lift (Cannizzaro 2009).
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Two trials compared different crestal sinus lift procedures (Checchi 2010; Crespi 2012).
Characteristics of outcome measures
-
Prosthesis failure: (Wannfors 2000; Hallman 2002; Raghoebar 2005; Cannizzaro 2009; Felice 2009a; Felice 2009b; Torres 2009; Checchi 2010; Felice 2011; Crespi 2012; Esposito 2012; Felice 2012; Lindgren 2012; Felice 2013; Merli 2013; Rickert 2013; Si 2013, Torres 2013).
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Implant failure by individual implant stability assessment with removed prostheses (with the exception of single implants): (Wannfors 2000; Hallman 2002; Raghoebar 2005; Cannizzaro 2009; Felice 2009a; Felice 2009b; Torres 2009; Checchi 2010; Felice 2011; Crespi 2012; Esposito 2012; Felice 2012; Lindgren 2012; Felice 2013; Merli 2013; Rickert 2013; Si 2013, Torres 2013).
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Augmentation procedure failure: (Wannfors 2000; Hallman 2002; Raghoebar 2005; Cannizzaro 2009; Felice 2009a; Felice 2009b; Torres 2009; Checchi 2010; Felice 2011; Crespi 2012; Esposito 2012; Felice 2012; Lindgren 2012; Felice 2013; Merli 2013; Rickert 2013; Si 2013; Torres 2013). In one trial (Si 2013), in the case of maxillary sinus membrane perforation patients were excluded and we classified these patients as failures of the augmentation procedures and for the rest of the rehabilitation.
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Complications: (Hallman 2002; Raghoebar 2005; Cannizzaro 2009; Felice 2009a; Felice 2009b; Torres 2009; Checchi 2010; Felice 2011; Crespi 2012; Esposito 2012; Felice 2012; Felice 2013; Merli 2013; Rickert 2013). Two trials reported only selected complications: perforation of the sinus membrane (Wannfors 2000; Torres 2013).
-
Patient satisfaction: (Felice 2011).
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Patient preference (only in split‐mouth trials): (Felice 2009a; Felice 2009b; Checchi 2010; Esposito 2012; Felice 2012). Data for one trial (Felice 2009a) were reported, however they might have been biased because of the study design. All augmentation procedures were performed first and, after four months, test and control implants were placed bilaterally in the same surgical session. The potential advantage of having the prostheses on the short implants loaded four months earlier was lost with this study design.
-
Bone gain expressed in millimetres or as a percentage: (Felice 2009b; Crespi 2012; Si 2013).
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Duration of the treatment period starting from the first intervention to the functional loading of the implants: all trials.
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Treatment costs: no trials. However, this outcome measure was indirectly extrapolated by us for all trials.
Duration of follow‐up (including unpublished data kindly provided by the investigators)
-
Five‐month post‐loading (Felice 2011).
-
Six‐month post‐loading (Merli 2013).
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One‐year post‐loading (Hallman 2002; Felice 2009a; Felice 2009b; Esposito 2012; Felice 2012; Felice 2013; Rickert 2013; Torres 2013).
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Nineteen‐month post‐loading (Crespi 2012).
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Two‐year post‐loading (Raghoebar 2005; Torres 2009).
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Two‐year and half post‐loading (Si 2013).
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Three‐year post‐loading (Wannfors 2000; Checchi 2010; Lindgren 2012).
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Five‐year post‐loading (Cannizzaro 2009).
Excluded studies
Forty‐five studies had to be excluded for various reasons such as: they reported only histological outcomes without presenting any implant‐related outcomes (Barone 2005; Kassolis 2005; Steigmann 2005; Froum 2006; Suba 2006; Consolo 2007; Aimetti 2008; Cordaro 2008; Froum 2008; Hallman 2008; Canullo 2009; Choi 2009; Crespi 2009; Kim 2009; Pikdöken 2011; Kühl 2012; Barone 2013; Corinaldesi 2013; Froum 2013; Kühl 2013; Payer 2013; Testori 2013; Yilmaz 2013); too short follow‐up (Szabó 2005; Barone 2008; Schaaf 2008; Bettega 2009; Badr 2010; Kock 2010; Bensaha 2011; Borges 2011; Sammartino 2011; Hermund 2012; Kühl 2012; Trombelli 2012; Froum 2013; Gassling 2013; Khairy 2013; Silvestri 2013); problems with study design and data reporting (Froum 1998; Tawil 2001; Boyne 2005; Triplett 2009; Wagner 2012); data presented for only four out of 16 treated patients (Aimetti 2008); not an RCT (Mangano 2007; Ghanaati 2014).
Risk of bias in included studies
Allocation
Random sequence generation
We assessed 14 studies as at low risk of bias for this domain, with four being assessed as unclear.
Allocation concealment
When assessing the information presented in the articles, allocation concealment was scored as adequate for 13 trials (Cannizzaro 2009; Felice 2009a; Felice 2009b; Torres 2009; Checchi 2010; Felice 2011; Esposito 2012; Felice 2012; Lindgren 2012; Felice 2013; Merli 2013; Si 2013; Torres 2013) and unclear for five trials (Wannfors 2000; Hallman 2002; Raghoebar 2005; Crespi 2012; Rickert 2013). When evaluating authors' replies one trial was judged to be properly concealed (Hallman 2002) and four trials remained unclear (Wannfors 2000; Raghoebar 2005; Crespi 2012; Rickert 2013). In Lindgren 2012, although the randomisation was unclear the envelope was opened after the sinus membrane was elevated.
Therefore, the overall risk of selection bias was low in 14 studies and unclear in four studies.
Blinding
Blinding was not feasible in all of the included studies. Based on the evaluation of the trial reports and responses from authors, outcome assessment was scored as blinded for 14 trials (Raghoebar 2005; Cannizzaro 2009; Felice 2009a; Felice 2009b; Torres 2009; Checchi 2010; Felice 2011; Crespi 2012; Esposito 2012; Felice 2012; Felice 2013; Rickert 2013; Si 2013; Torres 2013); not blinded for four trials (Wannfors 2000; Hallman 2002; Lindgren 2012; Merli 2013) although an independent assessor was used (Merli 2013). When reading the original articles blinding was unclear for five trials (Wannfors 2000; Hallman 2002; Torres 2009; Crespi 2012; Lindgren 2012) and one trial was not blinded (Merli 2013). When evaluating authors' replies, the outcome assessors of two trials were judged to be blinded (Torres 2009; Crespi 2012) and not blinded for three trials (Wannfors 2000; Hallman 2002; Lindgren 2012).
Incomplete outcome data
When assessing the information presented in the articles, information on drop‐outs was clearly presented in all trials with four exceptions (Torres 2009; Crespi 2012; Rickert 2013; Torres 2013) where the authors supplied the missing information. In another trial, in the case of maxillary sinus membrane perforation patients were excluded (Si 2013).
Selective reporting
Six trials did not present or only appeared to present full data on complications (Wannfors 2000; Crespi 2012; Lindgren 2012; Rickert 2013; Si 2013; Torres 2013), but the authors of three trials provided the missing information (Crespi 2012; Lindgren 2012; Rickert 2013); the remaining three trials were judged to be at high risk of bias since they did not answer to our request for information. Data for some of the outcome measures were not presented in one trial (Crespi 2012) resulting in it also being judged at high risk of bias.
Other potential sources of bias
Other potential sources of bias that were detected were: differences in implant diameters between groups (Cannizzaro 2009; Felice 2009a); and additional buccal onlays performed making more difficult result interpretation since the role of the additional buccal onlays on the final outcome cannot be quantified (Raghoebar 2005; Rickert 2013). These were assessed as at unclear risk of bias unless they were included in the following list. The following four trials were considered at high risk because: they used a mixed split‐mouth and parallel group design (Torres 2009); patients always had augmentation procedure performed first and then had implant placement bilaterally, since this may have affected patient preference (Felice 2009a); eight of 15 patients were treated by the inventor of one of the techniques under evaluation (Checchi 2010); it was a split‐mouth study not taking pairing into account (Rickert 2013).
Overall risk of bias
Looking at the summary risk of bias for each trial in Figure 1, five trials were judged to be at low risk of bias (Felice 2009b; Felice 2011; Esposito 2012; Felice 2012; Felice 2013), 11 trials were judged at high risk of bias (Wannfors 2000; Hallman 2002; Felice 2009a; Torres 2009; Checchi 2010; Crespi 2012; Lindgren 2012; Merli 2013; Rickert 2013; Si 2013; Torres 2013), and two trials at unclear risk of bias (Raghoebar 2005; Cannizzaro 2009).
Risk of bias summary: review authors' judgements about each risk of bias item for each included study.
Effects of interventions
See: Summary of findings for the main comparison Long implants with augmentation versus short implants without augmentation for replacing missing teeth; Summary of findings 2 Different sinus lift procedures
1. Long implants in augmented sinuses versus short implants without augmentation (four trials with 102 participants)
Seesummary of findings Table for the main comparison.
Four trials (Felice 2009a; Felice 2011; Esposito 2012; Felice 2012) provided data for this comparison where short implants without augmentation were compared with long implants with augmentation. Three of these trials were assessed as at low risk of bias (Felice 2011; Esposito 2012; Felice 2012) and one at high risk of bias (Felice 2009a). Although two of these were split‐mouth studies, the prosthesis and implant failures, and complications were in different patients and so the data have been entered as though they were in parallel group studies for ease of analysis and interpretation.
Prosthesis, implant and augmentation failures at one year
The meta‐analyses for prosthesis failures and implant failures are shown in Analysis 1.1 and Analysis 1.2. There was no evidence of a difference in prosthesis or implant failures for the long implants with augmentation compared with the short implants, however the confidence intervals were wide. The odds ratio (OR) (Peto) for prosthesis failures was 0.37 (95% confidence interval (CI) 0.05 to 2.68, P value = 0.33) with no evidence of heterogeneity. The OR (Peto) for implant failures was 0.44 (95% CI 0.10 to 1.99, P value = 0.29) with no evidence of heterogeneity. One bilateral augmentation failure occurred in one trial only (Felice 2011).
Complications at one year
The meta‐analysis for complications at treated sites is shown in Analysis 1.3. There was some evidence of more complications with the sinus lift, with an OR (Peto) of 4.77 (95% CI 1.79 to 12.71, P value = 0.002), however there was heterogeneity between the studies (Chi2 P value = 0.04, I2 = 64%).
Patient preference
Patient preference could only be ascertained in two split‐mouth studies. In Felice 2009a all patients expressed no preference for any of the two procedures at four months post‐loading, judging both of them as acceptable, however this measurement was considered to be biased as previously described in the 'Characteristics of outcome measures'. In Esposito 2012, five months after loading 15 patients preferred short implants whereas five patients described both procedures as equally acceptable.
Costs and treatment time
There were additional costs associated with the long implants with augmentation group: in Felice 2009a this group required one additional surgical intervention for placing the implants (two‐stage procedure) plus there was the cost of the bone substitute with the barrier and four additional months to complete the treatment; in Esposito 2012 and Felice 2012 there was the additional cost of the bone substitute with the barrier; and in Felice 2011 there were the additional costs of three days of hospitalisation, the barrier, and four additional months required to rehabilitate the patients. Also more implants were placed in the long implant group with augmentation in one trial (Felice 2011).
2. Comparing different sinus lift procedures (14 trials with 548 participants)
These comparisons frequently involved only one trial, and the results for all outcomes are presented in Additional Table 1. Only results for more than one trial were shown in forest plots.
| Comparison | Outcome | Data | Effect estimate (95% CI) P value |
| Rotary instruments versus piezosurgery
(Rickert 2013)
Split‐mouth | Prosthesis failures | N = 36; none | N/A |
| Implant failures | N = 36; none | N/A | |
| Augmentation procedure failure | N = 36; none | N/A | |
| Complications at augmented site | N = 36; both = 2, rotary only = 6, piezosurgery only = 6, neither = 22 | OR 1.00 (0.27 to 3.74) P = 1.00 | |
| Complications at donor site | N = 36; none | N/A | |
| With versus without bone graft
(Felice 2009b)
Split‐mouth | Prosthesis failures | N = 9; none | N/A |
| Implant failures | N = 9; 1 failure for without | OR 3.35 (0.12 to 93.8) P = 0.48 | |
| Complications (1 year) | N =9; both = 1, without = 2, with = 1, none = 5 | OR 0.50 (0.01 to 9.60) P = 1.00 | |
| Bone gain at 6 months | N = 9 | MD 0.26 (‐0.91 to 1.43) P = 0.65 | |
| With versus without bone graft
(Si 2013)
Parallel group | Prosthesis failures (1 year) | With bone versus without bone 2/22 versus 3/22 | OR 0.63 (0.10 to 4.22) P = 0.64 |
| Implant failures (1 year) | 2/22 versus 3/22 | OR 0.63 (0.10 to 4.22) P = 0.64 | |
| Augmentation procedure failure (1 year) | 1/22 versus 2/22 | OR 0.48 (0.04 to 5.67) P = 0.56 | |
| Complications (1 year) | Not reported | N/A | |
| Bone gain at 6 months | Graft N = 21 5.66 (SD 0.99) versus no graft N = 20 2.06 (1.01) | MD 3.60 (2.99 to 4.21) P < 0.001 | |
| Bone gain at 18 months | Graft N = 20 3.02 (SD 0.48) versus no graft N = 19 3.12 (0.70) | MD ‐0.10 (‐0.47 to 0.27) P = 0.60 | |
| Bone gain at 30 months | Graft N = 20 3.17 (SD 1.95) versus no graft N = 19 3.07 (1.68) | MD 0.10 (‐1.04 to 1.24) P = 0.86 | |
| Autogenous bone versus bone substitute
(Hallman 2002)
Split‐mouth | Implant failures (abutment connection) | N = 11; 5/11 autogenous bone versus 2/11 80% Bio‐Oss. Assume not bilateral | OR 3.75 (0.54 to 26.04) P = 0.18 |
| Complications | N = 11; none | N/A | |
| Autogenous bone versus bone substitute
(Merli 2013)
Parallel group | Implant failures | 2/20 versus 0/20 | OR 5.54 (0.25 to 123.08) P = 0.28 |
| Complications | 2/20 versus 1/20 | OR 2.11 (0.18 to 25.35) P = 0.56 | |
| Autogenous bone versus bone substitute (Lindgren 2012) Split‐mouth | Prosthesis failures | 0/11 versus 0/11 | N/A |
| Implant failures | 1/11 versus 1/11 | OR 1.00 (0.05 to 18.30) P = 1.00 | |
| Augmentation procedure failure | 0/11 versus 0/11 | N/A | |
| Complications at augmented site | N = 11; both = 0, Bio‐Oss only = 1, different bone substitute only = 0, neither = 10 | OR 3.29 (0.12 to 89.8) P= 0.48 | |
| Autogenous bone ± PRP
(Raghoebar 2005)
Split‐mouth | Prosthetic failures | N = 5; none | N/A |
| Implant failures | N = 5; 1 failure in PRP | OR 3.67 (0.12 to 113.73) P = 0.46 | |
| Complications | N =5; 1 occurred in non‐PRP | OR 0.27 (0.01 to 8.46) P = 0.46 | |
| Autogenous bone or Bio‐Oss ± PRP
(Torres 2009)
Split‐mouth | Implant failures | N = 57; both = 0, PRP only = 1, no PRP only = 2, neither = 54 | OR 0.50 (0.01 to 17.42) P = 0.71 |
| Complications | N = 57; both = 0, PRP only = 3, no PRP only = 2, neither = 52 | OR 1.49 (0.15 to 15.07) P = 1.00 | |
| Partial graft loss
| N = 57; both = 0, PRP only = 2, no PRP only = 3, neither = 52 | OR 1.5 (0.17 to 17.96) P = 1.00 (Stata exact OR) | |
| Membrane versus no membrane to seal the lateral window (Torres 2013) Parallel group | Prosthetic failures | 9/51 versus 4/53 | OR 2.63 (0.75 to 9.14) P = 0.13 |
| Implant failures | 9/51 versus 4/53 | OR 2.63 (0.75 to 9.14) P = 0.13 | |
| 1‐stage versus 2‐stage
(Felice 2013)
Parallel group | Prosthesis failures | 1‐stage versus 2‐stage 0/28 versus 1/30 | 0.35 (0.01 to 6.83) P = 0.52 |
| Implant failures (before loading) | 3/28 versus 1/30
| OR 3.48 (0.34 to 35.61) P = 0.29 | |
| Complications | 2/28 versus 1/30 | OR 2.23 (0.19 to 26.06) P = 0.52 | |
| 1‐stage block versus 2‐stage particulate bone
(Wannfors 2000)
Parallel group | Prosthetic failures | 1/20 versus 1/20 | OR 1.00 (0.06 to 17.18) P = 1.00 |
| Implant failures | 8/20 versus 6/20 | OR 1.56 (0.42 to 5.76) P = 0.51 | |
| Complications | 9/20 versus 10/20 | OR 0.82 (0.24 to 2.84) P = 0.75 | |
| Crestal versus lateral sinus lift
(Cannizzaro 2009)
Parallel group | Prosthetic failures | 1/20 versus 2/20 | OR 0.47 (0.04 to 5.69) P = 0.56 |
| Implant failures | 1/20 versus 3/20 | OR 0.30 (0.03 to 3.15) P = 0.31 | |
| Graft failures | 0/20 versus 2/20 | OR 0.18 (0.01 to 4.01) P = 0.28 | |
| Complications at treated and donor sites (1 year) | 1/20 versus 4/20 | OR 0.21 (0.02 to 2.08) P = 0.18 | |
| Partial graft loss
| 2/20 versus 3/20 | OR 0.63 (0.09 to 4.24) P = 0.63 | |
| Mallet versus rotary
(Checchi 2010)
Split‐mouth | Prosthetic failures | N = 12; none | N/A |
| Implant failures | N = 12; none | N/A | |
| Complications | N = 12; 5/12 versus 1/12 | OR 7.86 (0.75 to 82.13) P = 0.09 | |
| Preference 5 months after loading | N = 15; 13 preferred rotary technique | Binomial test P = 0.007 | |
| Hand mallet versus electric mallet (Crespi 2012)
Parallel group
Followed for 19 months after loading | Prosthesis failures | Hand mallet versus electric mallet 0/40 versus 0/40 | N/A |
| Implant failures (before loading) | 1/40 versus 1/40
| OR 1.00 (0.06 to 16.56) P = 1.00 | |
| Augmentation failures | 0/40 versus 0/40 | N/A | |
| Complications at augmented site | 3/40 versus 0/40 | OR 3.16 (0.31 to 31.78) P = 0.33 | |
| Bone gain | N = 40 4.17 (SD 1.70) versus N = 40 4.07 (SD 1.03) | MD 0.10 (‐0.52 to 0.72) P = 0.75 |
Data on patients who dropped out removed from the table.
CI ‐ confidence interval; MD ‐ mean difference; OR ‐ odds ratio; SD ‐ standard deviation.
Rotary instruments versus piezosurgery to open a lateral window in the maxillary sinus (one trial with 36 participants)
One trial at high risk of bias (Rickert 2013) with 36 patients undertook this comparison, at one year after loading. The following outcomes were reported and the data are given in Additional Table 1: prosthesis failure, implant failure, augmentation procedure failure, complications at augmented site and complications at donor site. None of these were significant.
Sinus lift with and without bone graft (two trials with 55 participants)
Two trials, one at low and one at high risk of bias (Felice 2009b; Si 2013), compared granular anorganic bovine bone (Bio‐Oss) with a resorbable rigid barrier (Inion) (Felice 2009b) or no bone (Si 2013) at one year. The following outcomes were reported and the data are given in Additional Table 1: prosthesis failure, implant failure, complications, augmentation procedure failure (one year), and bone gain (6, 18, 30 months after augmentation). Both studies provided data for bone gain at six months. This was significant for Si 2013 (P value < 0.001), with graft sites gaining more bone, but not for Felice 2009b. This observed gain in bone in Si 2013 was not apparent at 18 or 30 months.
The meta‐analysis of these two trials (Felice 2009b; Si 2013) for implant failures at one year is given in Analysis 2.1. There was no evidence to suggest that more implant failures occurred in sinus lift with or without a bone graft (OR 0.52, 95% CI 0.10 to 2.82).
There was heterogeneity between the studies so it was probably not advisable to pool the data for bone gain at six months (Analysis 2.2).
Autogenous bone versus bone substitutes (two trials with 51 participants)
Two trials that were both at high risk of bias (Hallman 2002; Merli 2013) provided data for this comparison. One trial (Hallman 2002) compared autogenous bone versus 80% anorganic bovine bone (Bio‐Oss) and 20% autogenous bone in 11 patients. The other trial (Merli 2013) compared autogenous bone harvested from the mandibular ramus versus anorganic bovine bone in 40 patients. Both trials reported implant failures and complications (none for Hallman 2002), and the data are shown in Additional Table 1 and a forest plot (Analysis 2.3). No statistically significant difference was found for implant failures (OR 4.20, 95% CI 0.81 to 21.79). For both trials the additional cost was that of the bone substitute.
Comparing different bone substitutes (one trial with 11 participants)
One trial at high risk of bias (Lindgren 2012) and with 11 patients undertook this comparison at one year after loading. The following outcomes were reported and the data are given in Additional Table 1: prosthesis failure, implant failure, augmentation procedure failure, and complications at augmented site. None of these were significant.
Grafts with or without platelet‐rich plasma (PRP) (two trials with 62 participants)
Two split‐mouth trials provided data for this comparison. One trial (Raghoebar 2005) with five patients was at unclear risk of bias and compared a two‐stage sinus lift with autogenous bone together with buccal onlay grafts that were harvested from the iliac crest, one side with PRP and the other without. The other trial (Torres 2009) with 57 patients was at high risk of bias and compared one‐ or two‐stage sinus lift procedures using a lateral window technique and 100% granular Bio‐Oss with or without PRP. Both trials provided useable data on implant failures and complications and forest plots are shown (Analysis 2.4). There were no statistically significant differences between groups who received PRP and those who did not for implant failures and complications. For both trials the difference in cost and treatment time was due to the use of PRP.
Use or not of a resorbable barrier to seal the lateral window (one trial with 106 participants)
One trial at high risk of bias (Torres 2013) and with 106 patients undertook this comparison at one year after loading. The following outcomes were reported and the data are given in Additional Table 1: prosthesis failure and implant failure. None of these were significant.
One‐stage versus two‐stage augmentation procedures (one trial with 60 participants)
One trial at low risk of bias (Felice 2013) and with 60 patients undertook this comparison at one year after loading. The following outcomes were reported and the data are given in Additional Table 1: prosthesis failure, implant failure, and complications. None of these were significant.
One‐stage blocks versus two‐stage sinus lift with autogenous granular bone (one trial with 40 participants)
One trial at high risk of bias (Wannfors 2000) and with 40 patients undertook this comparison at three years after loading. The following outcomes were reported and the data are given in Additional Table 1: prosthesis failure, implant failure, and complications. None of these were significant.
Comparing lateral versus crestal sinus lift (one trial with 40 participants)
One trial at unclear risk of bias (Cannizzaro 2009) and with 40 patients undertook this comparison at five years after loading. The following outcomes were reported and the data are given in Additional Table 1: prosthesis failure, implant failure, graft failure, complications, and partial graft loss. There were no statistically significant differences. There was an additional cost of the bone substitute in the group with the lateral approach but treatment duration was the same.
Comparing different crestal sinus lift procedures (two trials with 55 participants)
(a) Osteotomes with mallet versus sites prepared with rotary instruments
One trial at high risk of bias compared sinus lifting procedures performed bilaterally and in the same surgical session: the Summers' technique (using osteotomes and a mallet) and the Cosci's technique (sites prepared only with rotary instruments), in 15 patients (Checchi 2010). The following outcomes were reported and the data are given in Additional Table 1: prosthetic failure, implant failure, and complications at three years after loading. There were no failures in either group, and no statistically significant differences for these outcomes. Five months after loading (one year after surgery) 13 out of 15 patients preferred the side treated with the Cosci technique (P value < 0.007). Treatment duration and costs were the same.
(b) One‐stage crestal sinus lifting procedures: osteotomes with a hand mallet versus an electric mallet without placing any bone grafts
One trial at high risk of bias (Crespi 2012) and with 40 patients per group undertook this comparison at three years. The following outcomes were reported and the data are given in Additional Table 1: prosthesis failure, implant failure, augmentation failure, complications at augmented site, and bone gain. None of these were statistically significant.
Discussion
Summary of main results
Seesummary of findings Table for the main comparison; summary of findings Table 2.
Four trials evaluated whether sinus lift procedures are indicated in patients having a residual crestal height between 4 to 9 mm. There was moderate quality evidence, which was insufficient to determine whether procedures with or without using a sinus lift led to more prosthesis or implant failures. However, there were more complications at the treated sites when using the sinus lift procedures.
Several trials compared different sinus lift procedures. Data for prosthetic failure were available for five comparisons but with only one small trial in each. There was insufficient evidence to conclude that one sinus lift procedure had more or fewer prosthetic failures than the other. Eight comparisons, including one or two small studies, presented data on implant failures. There was insufficient evidence to conclude that one sinus lift procedure led to more implant failures than the other.
Given the lack of evidence to support one sinus lift procedure over another, clinicians should use their clinical judgement and take patient preference into account when choosing between procedures.
Overall completeness and applicability of evidence
Most of the augmentation procedures evaluated in these trials were performed by experienced clinicians, therefore caution is recommended when extrapolating the results of the present review to other clinical settings, such as general practice. There were insufficient studies comparing the same interventions to enable robust conclusions to be made via meta‐analysis.
Quality of the evidence
Four trials (102 participants) provided data for the first objective of the review, to compare interventions with and without a sinus lift procedure. These trials provided moderate quality evidence for prosthesis and implant failures, which was downgraded for imprecision.
Sample sizes were relatively small with only eight trials (Cannizzaro 2009; Felice 2009a; Checchi 2010; Felice 2011; Esposito 2012; Merli 2013; Si 2013; Torres 2013) reporting a sample size calculation and several of them were definitively underpowered to detect a clinically significant difference.
Potential biases in the review process
There were no events in some of the trial arms for some outcomes and we therefore used Peto odds ratios to undertake the meta‐analysis. This may lead to conservative estimates of the effect size.
Although two of these were split‐mouth studies, the prosthesis and implant failures, and complications were in different patients and so the data have been entered as though they are from parallel group studies for ease of analysis and interpretation. This is unlikely to have produced biased estimates.
Eleven of the 18 trials received funding from manufacturers of the interventions, however there was no evidence that this caused any bias in the assessment of the trials. This is not included in the risk of bias assessment in accord with Cochrane policy.
Agreements and disagreements with other studies or reviews
Several 'systematic' reviews have been published on the outcomes of sinus lifting procedures (Tong 1998; Wallace 2003; Del Fabbro 2004; Emmerich 2005; Aghaloo 2007; Pjetursson 2008; Tan 2008; Nkenke 2009; Del Fabbro 2013) however, since these findings were not based on the most reliable clinical studies, direct comparisons with our findings could be misleading and difficult to interpret.
Risk of bias summary: review authors' judgements about each risk of bias item for each included study.
Comparison 1 Long implants with sinus lift versus short implants without augmentation, Outcome 1 Prosthesis failures 1 year.
Comparison 1 Long implants with sinus lift versus short implants without augmentation, Outcome 2 Implant failures 1 year.
Comparison 1 Long implants with sinus lift versus short implants without augmentation, Outcome 3 Complications 1 year.
Comparison 2 Different sinus lift procedures, Outcome 1 Bone versus no bone graft.
Comparison 2 Different sinus lift procedures, Outcome 2 Bone versus no bone graft.
Comparison 2 Different sinus lift procedures, Outcome 3 Autogenous bone versus bone substitute.
Comparison 2 Different sinus lift procedures, Outcome 4 Autogenous bone or Bio‐Oss +/‐ PRP.
| Long implants with augmentation versus short implants without augmentation for replacing missing teeth: augmentation procedures of the maxillary sinus | ||||||
| Patient or population: patients with replacing missing teeth | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect | No of participants | Quality of the evidence | Comments | |
| Assumed risk | Corresponding risk | |||||
| Short implants | Long implants with sinus lift | |||||
| Prosthesis failures | Study population | OR 0.37 | 109 | ⊕⊕⊕⊝ | ||
| 55 per 1000 | 21 per 1000 | |||||
| Moderate | ||||||
| 50 per 1000 | 19 per 1000 | |||||
| Implant failures | Study population | OR 0.44 | 137 | ⊕⊕⊕⊝ | ||
| 71 per 1000 | 33 per 1000 | |||||
| Moderate | ||||||
| 50 per 1000 | 23 per 1000 | |||||
| Complications | Study population | OR 4.77 | 137 | ⊕⊕⊝⊝ | ||
| 43 per 1000 | 176 per 1000 | |||||
| Moderate | ||||||
| 50 per 1000 | 201 per 1000 | |||||
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI) | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded for imprecision (small number of events) | ||||||
| Comparison between different sinus lift procedures | |
| Patient or population: patients with insufficient bone below maxillary sinus Settings: dental practice Intervention: sinus lift procedure Comparison: sinus lift procedure | |
| Outcomes | Comments |
| Prosthesis failures (at 5 months to 5 years) | Data for prosthetic failures were present for 5 comparisons (all only including 1 small study). There is insufficient evidence to conclude that 1 sinus lift procedure leads to fewer prosthetic failures than another. The comparisons for this outcome were: bone graft versus no bone graft, 2 different bone substitutes, 1‐ versus 2‐stage lateral sinus lift, 2‐stage granular bone versus 1‐stage autogenous bone blocks, and crestal versus lateral sinus lift |
| Implant failures (at 5 months to 5 years) | Data for implant failures were present for 8 comparisons (including 1 or 2 small studies). There is insufficient evidence to conclude that 1 sinus lift procedure leads to fewer implant failures than another. The comparisons for this outcome were: bone graft versus no bone graft, autogenous bone versus bone substitute, bone graft with or without platelet‐rich plasma (PRP), 2 different bone substitutes, 1‐ versus 2‐stage lateral sinus lift, 2‐stage granular bone versus 1‐stage autogenous bone blocks, crestal versus lateral sinus lift, and hand versus electric malleting for crestal sinus lifting |
| Comparison | Outcome | Data | Effect estimate (95% CI) P value |
| Rotary instruments versus piezosurgery
(Rickert 2013)
Split‐mouth | Prosthesis failures | N = 36; none | N/A |
| Implant failures | N = 36; none | N/A | |
| Augmentation procedure failure | N = 36; none | N/A | |
| Complications at augmented site | N = 36; both = 2, rotary only = 6, piezosurgery only = 6, neither = 22 | OR 1.00 (0.27 to 3.74) P = 1.00 | |
| Complications at donor site | N = 36; none | N/A | |
| With versus without bone graft
(Felice 2009b)
Split‐mouth | Prosthesis failures | N = 9; none | N/A |
| Implant failures | N = 9; 1 failure for without | OR 3.35 (0.12 to 93.8) P = 0.48 | |
| Complications (1 year) | N =9; both = 1, without = 2, with = 1, none = 5 | OR 0.50 (0.01 to 9.60) P = 1.00 | |
| Bone gain at 6 months | N = 9 | MD 0.26 (‐0.91 to 1.43) P = 0.65 | |
| With versus without bone graft
(Si 2013)
Parallel group | Prosthesis failures (1 year) | With bone versus without bone 2/22 versus 3/22 | OR 0.63 (0.10 to 4.22) P = 0.64 |
| Implant failures (1 year) | 2/22 versus 3/22 | OR 0.63 (0.10 to 4.22) P = 0.64 | |
| Augmentation procedure failure (1 year) | 1/22 versus 2/22 | OR 0.48 (0.04 to 5.67) P = 0.56 | |
| Complications (1 year) | Not reported | N/A | |
| Bone gain at 6 months | Graft N = 21 5.66 (SD 0.99) versus no graft N = 20 2.06 (1.01) | MD 3.60 (2.99 to 4.21) P < 0.001 | |
| Bone gain at 18 months | Graft N = 20 3.02 (SD 0.48) versus no graft N = 19 3.12 (0.70) | MD ‐0.10 (‐0.47 to 0.27) P = 0.60 | |
| Bone gain at 30 months | Graft N = 20 3.17 (SD 1.95) versus no graft N = 19 3.07 (1.68) | MD 0.10 (‐1.04 to 1.24) P = 0.86 | |
| Autogenous bone versus bone substitute
(Hallman 2002)
Split‐mouth | Implant failures (abutment connection) | N = 11; 5/11 autogenous bone versus 2/11 80% Bio‐Oss. Assume not bilateral | OR 3.75 (0.54 to 26.04) P = 0.18 |
| Complications | N = 11; none | N/A | |
| Autogenous bone versus bone substitute
(Merli 2013)
Parallel group | Implant failures | 2/20 versus 0/20 | OR 5.54 (0.25 to 123.08) P = 0.28 |
| Complications | 2/20 versus 1/20 | OR 2.11 (0.18 to 25.35) P = 0.56 | |
| Autogenous bone versus bone substitute (Lindgren 2012) Split‐mouth | Prosthesis failures | 0/11 versus 0/11 | N/A |
| Implant failures | 1/11 versus 1/11 | OR 1.00 (0.05 to 18.30) P = 1.00 | |
| Augmentation procedure failure | 0/11 versus 0/11 | N/A | |
| Complications at augmented site | N = 11; both = 0, Bio‐Oss only = 1, different bone substitute only = 0, neither = 10 | OR 3.29 (0.12 to 89.8) P= 0.48 | |
| Autogenous bone ± PRP
(Raghoebar 2005)
Split‐mouth | Prosthetic failures | N = 5; none | N/A |
| Implant failures | N = 5; 1 failure in PRP | OR 3.67 (0.12 to 113.73) P = 0.46 | |
| Complications | N =5; 1 occurred in non‐PRP | OR 0.27 (0.01 to 8.46) P = 0.46 | |
| Autogenous bone or Bio‐Oss ± PRP
(Torres 2009)
Split‐mouth | Implant failures | N = 57; both = 0, PRP only = 1, no PRP only = 2, neither = 54 | OR 0.50 (0.01 to 17.42) P = 0.71 |
| Complications | N = 57; both = 0, PRP only = 3, no PRP only = 2, neither = 52 | OR 1.49 (0.15 to 15.07) P = 1.00 | |
| Partial graft loss
| N = 57; both = 0, PRP only = 2, no PRP only = 3, neither = 52 | OR 1.5 (0.17 to 17.96) P = 1.00 (Stata exact OR) | |
| Membrane versus no membrane to seal the lateral window (Torres 2013) Parallel group | Prosthetic failures | 9/51 versus 4/53 | OR 2.63 (0.75 to 9.14) P = 0.13 |
| Implant failures | 9/51 versus 4/53 | OR 2.63 (0.75 to 9.14) P = 0.13 | |
| 1‐stage versus 2‐stage
(Felice 2013)
Parallel group | Prosthesis failures | 1‐stage versus 2‐stage 0/28 versus 1/30 | 0.35 (0.01 to 6.83) P = 0.52 |
| Implant failures (before loading) | 3/28 versus 1/30
| OR 3.48 (0.34 to 35.61) P = 0.29 | |
| Complications | 2/28 versus 1/30 | OR 2.23 (0.19 to 26.06) P = 0.52 | |
| 1‐stage block versus 2‐stage particulate bone
(Wannfors 2000)
Parallel group | Prosthetic failures | 1/20 versus 1/20 | OR 1.00 (0.06 to 17.18) P = 1.00 |
| Implant failures | 8/20 versus 6/20 | OR 1.56 (0.42 to 5.76) P = 0.51 | |
| Complications | 9/20 versus 10/20 | OR 0.82 (0.24 to 2.84) P = 0.75 | |
| Crestal versus lateral sinus lift
(Cannizzaro 2009)
Parallel group | Prosthetic failures | 1/20 versus 2/20 | OR 0.47 (0.04 to 5.69) P = 0.56 |
| Implant failures | 1/20 versus 3/20 | OR 0.30 (0.03 to 3.15) P = 0.31 | |
| Graft failures | 0/20 versus 2/20 | OR 0.18 (0.01 to 4.01) P = 0.28 | |
| Complications at treated and donor sites (1 year) | 1/20 versus 4/20 | OR 0.21 (0.02 to 2.08) P = 0.18 | |
| Partial graft loss
| 2/20 versus 3/20 | OR 0.63 (0.09 to 4.24) P = 0.63 | |
| Mallet versus rotary
(Checchi 2010)
Split‐mouth | Prosthetic failures | N = 12; none | N/A |
| Implant failures | N = 12; none | N/A | |
| Complications | N = 12; 5/12 versus 1/12 | OR 7.86 (0.75 to 82.13) P = 0.09 | |
| Preference 5 months after loading | N = 15; 13 preferred rotary technique | Binomial test P = 0.007 | |
| Hand mallet versus electric mallet (Crespi 2012)
Parallel group
Followed for 19 months after loading | Prosthesis failures | Hand mallet versus electric mallet 0/40 versus 0/40 | N/A |
| Implant failures (before loading) | 1/40 versus 1/40
| OR 1.00 (0.06 to 16.56) P = 1.00 | |
| Augmentation failures | 0/40 versus 0/40 | N/A | |
| Complications at augmented site | 3/40 versus 0/40 | OR 3.16 (0.31 to 31.78) P = 0.33 | |
| Bone gain | N = 40 4.17 (SD 1.70) versus N = 40 4.07 (SD 1.03) | MD 0.10 (‐0.52 to 0.72) P = 0.75 | |
| Data on patients who dropped out removed from the table. | |||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Prosthesis failures 1 year Show forest plot | 3 | 109 | Peto Odds Ratio (Peto, Fixed, 95% CI) | 0.37 [0.05, 2.68] |
| 2 Implant failures 1 year Show forest plot | 4 | 137 | Peto Odds Ratio (Peto, Fixed, 95% CI) | 0.44 [0.10, 1.99] |
| 3 Complications 1 year Show forest plot | 4 | 137 | Peto Odds Ratio (Peto, Fixed, 95% CI) | 4.77 [1.79, 12.71] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Bone versus no bone graft Show forest plot | 2 | Odds Ratio (Fixed, 95% CI) | Subtotals only | |
| 1.1 Implant failures (1 year) | 2 | Odds Ratio (Fixed, 95% CI) | 0.52 [0.10, 2.82] | |
| 2 Bone versus no bone graft Show forest plot | 2 | Mean Difference (Fixed, 95% CI) | 2.89 [2.35, 3.43] | |
| 2.1 Bone gain | 2 | Mean Difference (Fixed, 95% CI) | 2.89 [2.35, 3.43] | |
| 3 Autogenous bone versus bone substitute Show forest plot | 2 | Odds Ratio (Fixed, 95% CI) | Subtotals only | |
| 3.1 Implant failures | 2 | Odds Ratio (Fixed, 95% CI) | 4.20 [0.81, 21.79] | |
| 4 Autogenous bone or Bio‐Oss +/‐ PRP Show forest plot | 2 | Odds Ratio (Fixed, 95% CI) | Subtotals only | |
| 4.1 Implant failures | 2 | Odds Ratio (Fixed, 95% CI) | 1.40 [0.12, 16.52] | |
| 4.2 Complications | 2 | Odds Ratio (Fixed, 95% CI) | 0.88 [0.13, 6.09] | |
