Efficacy of Injectable Bone Fillers for Alveolar Ridge Preservation: A Histomorphometrical Analysis.

AIM To assess the efficacy of injectable bone fillers for alveolar ridge preservation (ARP). MATERIALS AND METHODS The mandibular premolars (P2, P3, P4) were bilaterally assigned to ARP in a total of n = 9 beagle dogs. Each P was decapitated and hemisected under preservation of the mesial (i.e., devitalization and filling with calcium hydroxide) and removal of the distal root. The resulting 6 extraction sockets were randomly allocated to a total of four injectable test materials (i.e., bovine bone particles + porcine collagen, lyophilized materials reconstituted with either blood or saline [T1, T2, T4]; or ready-to-use wet material [T3]) and one control material (collagenated bovine bone mineral) (C) as well as one negative control group (N). Primary wound closure was ensured in all test and C groups. At 12 weeks, dissected blocks were prepared for histomorphometrical analyses. Buccal bone height (BBH) was defined as a primary outcome. Lingual bone height (LBH), buccal and lingual bone wall width (BBW and LBW 1, 3 and 5 mm infracrestally), surface area of bone and particles, fibrous tissues, and bone marrows were defined as secondary outcomes. Between-group comparisons were assessed using ANOVA and Mann-Whitney tests. RESULTS After 12 weeks, all groups were associated with similar BBH values (BBH: 14.1, 14.0, 13.7, 13.8, 14.3 and 114.2 mm in the T1, T2, T3, T4, C and N groups, respectively; p > 0.05 for all between-group comparisons). The BBW and LBW measurements were comparable among the groups. ARP sites showed a trend towards higher area measurements of bone and particle surfaces compared with the N group (11.5, 11.6, 13.1, 12.5, 9.1 mm2 in T1, T2, T3, T4, C and N groups, respectively). C, T1, T2, T3 and T4 particles were associated with a similar marked grade of osteoconduction and osteointegration within the former extraction socket area. CONCLUSIONS Within its limitations, the present study has pointed to the similar efficacy of injectable bone fillers for ARP compared with the particulated bone substitute and negative control.