Date on Master's Thesis/Doctoral Dissertation

12-2012

Document Type

Master's Thesis

Degree Name

M.S.

Department

Oral Biology

Committee Chair

Greenwell, Henry

Author's Keywords

Ridge preservation; papilla preservation; allograft; xenograft

Subject

Gums--Surgery; Bone-grafting; Dental implants

Abstract

Aim. The efficacy of ridge preservation procedures using grafting materials and barrier membranes has been well established in the literature. However, the loss of horizontal width even with the utilization of intrasocket only guided bone regeneration procedures can lead to loss of soft and hard tissue contour or even compromise implant placement. The primary aim of this study was to compare ridge preservation using an intrasocket mineralized particulate cancellous allograft to an intrasocket mineralized particulate cancellous allograft plus a facial overlay with a particulate bovine xenograft, both covered with a bioresorbable barrier membrane. Clinical and histologic data was used to assess the outcomes. Methods. Twelve positive controls received an intrasocket mineralized cancellous particulate allograft 500-800 flm (lntrasocket group) while twelve test patients received an intrasocket mineralized cancellous particulate allograft 500 to 800 flm plus a facial overlay with a particulate bovine xenograft 250-1000 flm (Overlay group). All sites included in the study were covered with a bioresorbable poly (D,L lactic) acid barrier membrane. Only non-molar sites were included bordered with at least one tooth mesially or distally. Following tooth extraction and at 4-month re-entry, horizontal ridge dimensions were measured with a digital caliper and vertical ridge changes were measured from a resin- fabricated 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 crestal ridge width at the crest for the Intrasocket group decreased from 8.7 ± 1.0 mm to 7.1 ± 1.5 mm for a mean loss of 1.6 ± 0.8 mm (p < 0.05) while the Overlay group decreased from 8.4 ± 1.4 mm to 8.1 ± 1.4 mm for a mean loss of 0.3 ± 0.9 mm (p > 0.05). The difference between the two groups was statistically significant (p < 0.05). The mean mid-buccal vertical change for the lntrasocket group was gain of 0.5 ± 2.9 mm (p > 0.05) vs. a gain of OJ ± 2.6 mm for the Overlay group (p > 0.05). There were no statistically significant differences between groups for vertical change (p > 0.05) except for the distal vertical change (p < 0.05). Histologic analysis revealed that the Intrasocket group had 35 ± 16% vital bone, 21 ± 13% non-vital bone, 44 ± 9% trabecular space, while the Overlay group had 40 ± 16% vital bone, 17 ± II % nonvital bone, and 43 ± 12% trabecular space. There were no statistically significant differences between groups for vital and non-vital 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 Overlay group, however, showed significantly better horizontal ridge dimensions compared to the Intrasocket group. The percentage of vital bone achieved was similar for both groups.

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