Histomorphometry of Three Graft Products for Ridge Preservation; Pilot Study

Objectives: After tooth extraction, the success of future treatment options is dependent on the status of the alveolar ridge. At this biologically and biomechanically active site, rapid integration of any graft material is imperative to avoid loss of the ridge. Good graft biocompatibility should yield active bone ingrowth and bone-graft integration. In this pilot study, we examined the short-term (<6wk) jaw histomorphometry resulting from the use of a particulate and two solid grafting materials in a canine model. Previously, we reported on qualitative histology for these specimens.
Methods: Under local IACUC approval, 12 adult dogs were anesthetized, and the left mandibular premolar 4 (PM4) was extracted and replaced with (a) hydroxyapatite particulate (current commercially used product), (b,c) two configurations of an experimental hydroxyapatite-PLGA 3-D printed construct, or (d) unfilled socket (negative control; 3dogs/treatment). 2 and 3 wks postoperatively, dogs were labeled with IV tetracycline. Dogs were sacrificed at 39d and the surgical and contralateral mandibular PM4 sites prepared for static and dynamic undecalcified histomorphometry at five anatomic sites around the socket (Apical, Buccal occlusal, Buccal middle depth, Lingual occlusal, Lingual middle depth). 2-way RM-ANOVAe were performed for each output parameter at each site, examining the effect of treatment (Particulate, each of two Solid Materials, or Empty Socket) and side (surgical or contralateral). Alpha=0.05 for main effects, 0.1 for interactions, and 0.05 for post-hoc Fisher tests.
Results: Biocompatibility was adequate to good for all treatments. Remodeling was active, and many histomorphometric parameters showed a significant treatment-side interaction, especially in buccal and apical sectors.
Conclusions: These data suggest a transfer of masticatory load to the non-surgical side that was dependent on the type of graft. In general, the solid materials appeared to allow for early use of the surgical site, with less contralateral remodeling, than either the particulate or the empty-socket options.