Ridge preservation in molar extraction sites comparing xenograft versus mineralized freeze-dried bone allograft: a randomized clinical trial

Abstract

Objectives: To compare the dimensional changes and the histological composition after the use of an allograft or xenograft and a resorbable membrane in ridge preservation in molar sites, to evaluate the influence of bone plates thickness on dimensional changes and the frequency of lateral sinus lift following ridge preservation. Material and methods: Twenty-four patients in need of maxillary or mandibular first or second molar extraction and subsequent implant placement were included and randomly assigned to a group; allograft or xenograft, plus a collagen membrane. Cone Beam Computed Tomographies were obtained after molar extraction and after five months. A bone sample was harvested at the time of implant placement and analysed by histomorphometry. Results: Bone ridge was reduced significantly. Major changes in width occurred at 1 mm from the bone crest (-2.93 ± 2.28 mm) (p = 0.0002), while in height, the greatest reduction occurred at the buccal area (-1.97 ± 2.21 mm) (p = 0.0006). However, differences between groups were not significant. The thickness of the buccal bone plate influenced dimensional changes. Histologically, both biomaterials showed similar results. The resulting available bone height in the implant site measured 7.30 ± 3.53 mm initially and 6.8 ± 3.61 mm after 5 months which allowed implant placement without the need of external sinus lift in all cases. Still, 55% of the preserved areas needed transcrestal crestal sinus lift. Conclusion: Ridge preservation in molar sites with the use of allograft or xenograft provide similar results dimensional and histomorphometrically after five months.