Should the ossicle be denuded prior to the application of glass ionomer cement? An experimental study on rabbit

The objective of this study was to assess whether denudation of the auditory ossicle prior to the application of glass ionomer cement (GIC) durably strengthens the adhesion between bone and GIC. The tympanic bullas of 34 rabbits were opened bilaterally. The mucosa was removed from the lateral surface of the right-side incudi with a diamond burr, while the left-side incudi were left intact. GIC was then applied bilaterally to the lateral surface of the incudi of 30 of these rabbits which were subsequently killed 1, 3, 7, 14, 21, 30, 60, 90, 180 or 365 days postoperatively. The 4 sham-operated animals were killed on day 1, 7, 30 or 365. The incudi were removed and processed for histological evaluation. On exploration, the cement was visible on the incus within the tympanic bulla in all 30 GIC-treated animals. During surgical removal, the GIC was separated from the incus in 3 ears. Histological examination further revealed separation in 5 ears after processing. All 8 separations occurred in the right (not denuded) ears, and at least 60 days postoperatively. The difference between the two sides in the number of separations was significant (p < 0.05). The initial inflammatory reaction elicited by the surgical trauma to the right-side ossicles had substantially decreased by day 7. No foreign body reaction was observed and the GIC became overgrown with mucosa by day 60. In conclusion, the GIC proved biocompatible, and preliminary denudation of the ossicle resulted in stronger and more durable bone-GIC adhesion.