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Clinical Oral Investigations

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01-07-2016 | Original Article

Accounting for measurement reliability to improve the quality of inference in dental microhardness research: a worked example

Authors: Ivan Sever, Eva Klaric, Zrinka Tarle

Published in: Clinical Oral Investigations | Issue 6/2016

Abstract

Objectives

Dental microhardness experiments are influenced by unobserved factors related to the varying tooth characteristics that affect measurement reproducibility. This paper explores the appropriate analytical tools for modeling different sources of unobserved variability to reduce the biases encountered and increase the validity of microhardness studies.

Materials and methods

The enamel microhardness of human third molars was measured by Vickers diamond. The effects of five bleaching agents—10, 16, and 30 % carbamide peroxide, and 25 and 38 % hydrogen peroxide—were examined, as well as the effect of artificial saliva and amorphous calcium phosphate. To account for both between- and within-tooth heterogeneity in evaluating treatment effects, the statistical analysis was performed in the mixed-effects framework, which also included the appropriate weighting procedure to adjust for confounding. The results were compared to those of the standard ANOVA model usually applied.

Results

The weighted mixed-effects model produced the parameter estimates of different magnitude and significance than the standard ANOVA model. The results of the former model were more intuitive, with more precise estimates and better fit.

Conclusions

Confounding could seriously bias the study outcomes, highlighting the need for more robust statistical procedures in dental research that account for the measurement reliability. The presented framework is more flexible and informative than existing analytical techniques and may improve the quality of inference in dental research.

Clinical relevance

Reported results could be misleading if underlying heterogeneity of microhardness measurements is not taken into account. The confidence in treatment outcomes could be increased by applying the framework presented.

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Title: Accounting for measurement reliability to improve the quality of inference in dental microhardness research: a worked example
Authors: Ivan Sever
Eva Klaric
Zrinka Tarle
Publication date: 01-07-2016
Publisher: Springer Berlin Heidelberg
Published in: Clinical Oral Investigations / Issue 6/2016
Print ISSN: 1432-6981
Electronic ISSN: 1436-3771
DOI: https://doi.org/10.1007/s00784-015-1600-7

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Springer Medicine

Accounting for measurement reliability to improve the quality of inference in dental microhardness research: a worked example

Abstract

Objectives

Materials and methods

Results

Conclusions

Clinical relevance

Keynote webinar | Spotlight on medication adherence

Springer Medicine

Abstract

Objectives

Materials and methods

Results

Conclusions

Clinical relevance

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