Calcium sulfate (CS) has been shown to be an effective resorbable biomaterial for guided tissue regeneration, sinus augmentation, and bone regeneration. However, consistent and predictable clinical outcomes are not always possible due to the rapid rate at which calcium sulfate resorbs in vivo. As a result, it has been hypothesized that the longevity of calcium sulfate can be increased utilizing poly L-lactic acid (PLLA), a resorbable polymer, as a barrier coating. Objectives: This in vitro study evaluated dissolution rates of calcium sulfate pellets treated with PLLA and untreated CS pellets. Methods: Calcium sulfate was prepared to yield low viscosity PLLA composite pellets, high viscosity PLLA composite pellets, and control CS pellets run in triplicate. Pellets were incubated in simulated body fluid (SBF) at 37°C for 75 days, and weight measurements and media change was performed twice per week. Additional high viscosity pellets were fabricated and incubated in SBF for 28 days for SEM and X-ray microprobe analysis. Results: Results demonstrated that control pellets experienced a more rapid mass loss compared to composite pellets. In addition, ANOVA testing indicated that by three weeks of incubation, there was a statistically significant difference between the high viscosity pellets compared to the control (p<0.05). This difference was maintained throughout the course of the study. SEM analysis indicated that by four weeks incubation, there was evidence of PLLA mineralization throughout the coating. X-ray microprobe analysis indicated that this mineralization contained a calcium phosphate precipitate. Conclusions: These preliminary results demonstrate the efficacy of PLLA-CS composite pellets in maintaining calcium sulfate mass in vitro. Future studies are necessary to determine the mechanism behind calcium phosphate mineralization and ideal PLLA coating thicknesses to achieve a more practical CS half-life.

Back to the Dental Materials: VIII - Others-Non-metallic Program
Back to the IADR/AADR/CADR 80th General Session (March 6-9, 2002)

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