Comparison of Dehydrated Human Amnion-Chorion and Type 1 Bovine Collagen Membranes in Alveolar Ridge Preservation: A Clinical and Histological Study
Alveolar ridge preservation maintains ridge dimensions and bone quality for implant placement. The aim of this randomized controlled clinical study is to compare the use of a human amnion-chorion membrane to a collagen membrane in an exposed-barrier ridge preservation technique. Furthermore, this study will determine if intentional membrane exposure compromises ridge dimensions and bone vitality. Forty-three patients requiring extraction and delayed implant placement were randomly assigned into either the experimental or control group. Twenty-one participants received human amnion-chorion membrane (test) during ridge preservation while 22 participants received the collagen membrane (control). In both groups, demineralized freeze-dried bone allografts were used to graft the socket and primary closure was not achieved. The patients underwent implant placement after an average healing period of 19.5 weeks, and 2.7 × 8-mm core bone specimens were obtained for histomorphometric analyses. The clinical ridge dimensions were measured after extraction and at the time of delayed implant placement. No significant difference was observed in the mean vital bone formation between the experimental (51.72 ± 8.46%) and control (49.96 ± 8.31%; P > .05) groups. The bone height and width did not differ, as determined by clinical measurements (P > .05). Using either a human amnion-chorion membrane or type 1 bovine collagen as the open barrier did not change healing, compromise ridge dimensions, or affect bone vitality between the 2 groups.
Study flowchart.
(a through l) Ridge preservation and implant placement. No primary closure was achieved: (a–f) control group (collagen membrane); (g–l) experimental group (human amnion-chorion membrane). (m through t) Clinical measurements, implant positioning, and bone core site; control group (m) clinical height; (n) clinical width; (o) implant position; (p) bone core; experimental group: (q) clinical height; (r) clinical width; (s) implant position; (t) bone core.
(a) Bone core collagen group: Graft particles (GP) with empty lacunae devoid of nuclei (black arrow); vital bone (VB): osteocytes with nuclei in the lacunae (blue arrows); connective tissue (CT). (b) Bone core human amnion chorion group: GP with empty lacunae devoid of nuclei (black arrow); VB: osteocytes with nuclei in the lacunae (blue arrows); CT: loose fibrous tissue with fibroblasts; newly mineralizing bone (NMB): well-organized collagen fibrils within a dense active CT (yellow arrows).
(a through j) Site excluded from clinical measurements only: (a) buccal vertical defect >4 mm; (b–e) Ridge preservation performed similarly to the included sites; (f and g) reentry stage: ridge regeneration was evaluated; (h and i) implant and bone biopsy; (j) healing abutment placed after 4 months from implant placement.
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