Influence of healing time on the outcomes of alveolar ridge preservation using a collagenated bovine bone xenograft: A randomized clinical trial

AIM: To evaluate the healing outcomes in non‐molar post‐extraction sockets filled with deproteinized bovine bone mineral with collagen (DBBM‐C) as a function of time. MATERIALS AND METHODS: Patients in need of non‐molar tooth extraction were randomly allocated into one of three groups according to the total healing time (A—3 months; B—6 months; C—9 months). The effect of alveolar ridge preservation (ARP) therapy via socket filling using DBBM‐C and socket sealing with a porcine collagen matrix (CM) was assessed based on a panel of clinical, digital, histomorphometric, implant‐related, and patient‐reported outcomes. RESULTS: A total of 42 patients completed the study (n = 14 in each group). Histomorphometric analysis of bone core biopsies obtained at the time of implant placement showed a continuous increase in the proportion of mineralized tissue with respect to non‐mineralized tissue, and a decrease in the proportion of remaining xenograft material over time. All volumetric bone and soft tissue contour assessments revealed a dimensional reduction of the alveolar ridge overtime affecting mainly the facial aspect. Linear regression analyses indicated that baseline buccal bone thickness is a strong predictor of bone and soft tissue modelling. Ancillary bone augmentation at the time of implant placement was needed in 16.7% of the sites (A:2; B:1; C:4). Patient‐reported discomfort and wound healing index scores progressively decreased over time and was similar across groups. CONCLUSIONS: Healing time influences the proportion of tissue compartments in non‐molar post‐extraction sites filled with DBBM‐C and sealed with a CM. A variable degree of alveolar ridge atrophy, affecting mainly the facial aspect, occurs even after performing ARP therapy. These changes are more pronounced in sites exhibiting thin facial bone (≤1 mm) at baseline (Clinicaltrials.gov NCT03659617).