Fresh extraction socket: Spontaneous healing vs. immediate implant placement

Aim: To evaluate the impact that immediate implant placement may have on bone remodelling in comparison with adjacent sockets left to heal spontaneously. Materials and methods: In a beagle dog model (N = 16 dogs), mandibular premolars were extracted, and implants were placed in each distal socket (test) with the corresponding mesial site left to heal undisturbed (control). Healing was assessed measuring both the vertical distance between buccal and lingual crest (B'L') and the width of buccal and lingual walls at different levels. Five healing periods were evaluated. Differences between means for each variable and for each healing period between test and control were compared (Kruskal-Wallis test; Friedman test). Results: At 2 and 8 weeks of healing, the B'L' distance revealed significant higher values at test compared to control sites, being this difference three times higher at the end of the study (P < 0.05). In the test group, the width of the crest was reduced between baseline (0.37 [0.04]) and 8 weeks healing (0.13 [0.64]), demonstrating a 62% reduction of the initial width. These differences were not observed in the control group. Conclusions: Immediate implant placement into fresh extraction sockets may jeopardize the vertical bone remodelling of the socket. Furthermore, a tendency towards greater buccal horizontal resorption was observed in the most coronal aspect of the buccal bone crest.