Clinical assessment of bone quality of human extraction sockets after conversion with growth factors.

PURPOSE: The study was conducted to evaluate the effect of mineralized freeze-dried bone allograft (FDBA), alone or in combination with growth factors in extraction sockets, on subjective assessment of bone quality during implant placement. MATERIALS AND METHODS: Forty-one patients whose treatment plan involved extraction of anterior or premolar teeth were randomized into four groups: Group 1, collagen plug (control); Group 2, FDBA/ß-tricalcium phosphate (ß-TCP)/collagen plug; Group 3, FDBA/ß-TCP/platelet-rich plasma (PRP)/collagen plug; Group 4, FDBA/ß-TCP/recombinant human platelet-derived growth factor BB (rhPDGF-BB)/collagen plug. After 8 weeks of healing, implants were placed. The clinicians assessed bone quality according to the Misch classification. A benchtop calibration exercise test was conducted to evaluate agreement and accuracy of operators in recognizing different bone qualities. Differences were analyzed using one-way analysis of variance (ANOVA) or chi-square tests for continuous and categorical data. Pairwise comparisons were tested using least squares means (LS means). Spearman correlation coefficients were used to evaluate the relationship of bone growth with potential confounders. P < .05 was considered statistically significant. A simple (not weighted) kappa statistic was used to assess the agreement between raters. To assess accuracy in identifying bone quality, a chi-square test was used to compare the percent correct for each rater. RESULTS: The benchtop calibration exercise test demonstrated agreement among clinicians (0.75 and 0.92 between raters 1 and 2 and raters 1 and 3, respectively). Raters were more likely to identify the correct bone quality (P > .05). Inclusion of bone grafting is associated with a shift from D4 quality to D3 quality bone. Inclusion of PRP in bone grafting eliminates the incidence of D4 bone, establishing D3 and D2 quality bone as prevalent (56% vs. 42%, respectively). Inclusion of rhPDGF-BB and ß-TCP in combination with the bone grafting has the same effect, although D2 quality is less prevalent. When compared to sockets grafted with FDBA/ß-TCP/collagen plug alone, the sockets with growth factors demonstrated fewer residual bone graft particles. CONCLUSION: (1) Inclusion of bone grafting enhanced bone quality as assessed during implant placement. (2) Overall inclusion of PRP and rhPDGF-BB enhanced subjective bone quality, eliminating incidence of D4 quality in human extraction sockets. (3) The use of PRP or rhPDGF-BB may enhance healing within extraction sockets and decrease the healing time prior to dental implant placement.

Clinical and histologic assessment of lateral alveolar ridge augmentation using a synthetic long-term bioabsorbable membrane and an allograft.

BACKGROUND: Guided bone regeneration (GBR) is a widely used procedure for augmenting alveolar ridge width prior to placement of endosseous implants. Various graft materials and barrier membranes (non-resorbable and bioabsorbable) have been used in GBR. The aim of this study was to assess the performance of a new bioabsorbable, synthetic polyglycolic acid/trimethylene carbonate (PGA/TMC) barrier membrane with an increased absorption time in conjunction with a combination of assayed demineralized bone matrix and cortical cancellous chips uniformly dispersed in a thermoplastic biologic carrier. METHODS: At 72 potential implant sites in 38 subjects, ridge width at the crest and 4 mm apical to the crest was measured before and 6 months after a GBR procedure using the long-term (LT) PGA/TMC membrane and an allograft in a thermoplastic carrier. Before placement of endosseous implants, 48 biopsy specimens were obtained from the augmentation sites and analyzed histomorphometrically. RESULTS: The GBR procedure increased the mean ridge width at the crest from 2.4 to 5.2 mm. This 216% change from baseline was significant (P <0.001). The mean width 4 mm apical to the crest increased from 4.4 to 7.5 mm, a significant (P <0.001) 174% change. The histomorphometric analysis showed that the biopsy specimens consisted, on average, of 57% bone (36% graft material and 21% new bone) and 43% soft tissue and space. CONCLUSION: Our findings suggest that the LT PGA/TMC barrier membrane, used in conjunction with an allograft, provides lateral alveolar ridge augmentation comparable to that achieved with other materials without the necessity for bone-graft harvesting or a second procedure to remove the barrier membrane.