Date on Master's Thesis/Doctoral Dissertation

12-2011

Document Type

Master's Thesis

Degree Name

M.S.

Department

Oral Biology

Committee Chair

Greenwell, Henry

Subject

Dental implants; Gums--Surgery; Bone-grafting

Abstract

Aim. Differences in the healing of demineralized and mineralized allografts have been reported but their significance has not been evaluated in ridge preservation studies. The primary aims of this study were to compare ridge preservation using a mineralized cancellous allograft to a demineralized cortical allograft plus a PTFE barrier using clinical and histologic data to assess the outcomes. Methods. Twelve positive controls received an intrasocket mineralized cancellous particulate allograft (500-800 µm, Cancellous group) while twelve test patients received an intrasocket demineralized particulate allograft (250 to 710 µm, Demineralized group). All sites included in the study were covered with a PTFE barrier. Only nonmolar sites were included. Following tooth extraction and 4 month re-entry, horizontal ridge dimensions were measured with a digital caliper and vertical ridge changes were measured from a stent. Each site was re-entered for implant placement at about 4 months. Prior to implant placement, a 2.7 X 6 mm trephine core was obtained and preserved in formalin for histologic analysis. Results. The mean horizontal ridge width at the crest for the Cancellous group decreased from 8.2 ± 1.5 mm to 6.9 ± 1.5 mm for a mean loss of 1.3 ± 1.4 mm (p < 0.05) while the Demineralized group decreased from 9.1 ± 1.4 mm to 6.7 ± 1.6 mm for a mean loss of 2.5 ± 1.7 mm (p < 0.05). There were no statistically significance differences between the two groups (p > 0.05). The mean mid-buccal vertical change for the Cancellous group was gain of 0.6 ± 2.3 mm (p > 0.05) vs. a loss of 0.8 ± 0.8 mm for the Demineralized group (p > 0.05). There were no statistically significant differences between groups for vertical change (p > 0.05). Histologic analysis revealed that the Cancellous group had 38 ± 14% vital bone, 29 ± 14% non-vital bone, 32 ± 10% trabecular space, while the Demineralized group had 40 ± 13% vital bone, 21 ± 14% non-vital bone, and 39 ± 11 % trabecular space. There were no statistically significant differences between groups for vital and novital bone or for trabecular space (p > 0.05). Conclusions. Both treatments were effective in the preservation of horizontal and vertical ridge dimensions at sites for future implant placement. The Demineralized group, however, healed with a high percentage of vital bone, despite previous reports to the contrary, and the percentage of vital bone was similar to the amount achieved by the Cancellous group.

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