Preclinical comparison study of experimental peri-implantitis between alveolar ridge preservation and spontaneous healing sites in infected and noninfected tooth: a randomized blinded in vivo study.

Background: This study compared the progression of experimental peri-implantitis between alveolar ridge preservation (ARP) and spontaneous healing (SH) sites in infected (IT) and noninfected tooth (NIT).

Methods: Bilateral mandibular third or fourth premolars of six beagle dogs were randomly assigned to IT and NIT groups. Before extraction, chronic dehiscence defects were created at the mesial root of mid-buccal area in IT group. Four weeks later, the mesial roots of the third and fourth premolars were extracted in all groups.ARP procedure was randomly conducted on one side of the extraction sockets using collagenated bovine bone substitutes and resorbable collagen membrane, and contralateral side was allowded spontaneous healing. After 12 weeks of healing, bone-level implants (ϕ 3.6 × 8.0 mm) were placed at the extraction sockets. Three months of ligature induced peri-implantitis and three months of spontaneous progression were allowed, with radiographs taken at each phase. Biopsies were retrieved at the implant site for histomorphometric, immunohistochemical, and polarized light-microscopic analyses.

Results: Radiography demonstrated that the changes in the marginal bone level during the spontaneous progression period showed no significant differences between ARP and SH sites. Only small and/or nonsignificant differences in the progression of peri-implantitis were observed between ARP and SH sites in histomorphometric, immunohistochemical, and polarized light microscopic analyses. Additionally, the IT and NIT groups exhibited similar outcomes for most parameters.

Conclusion: ARP with xenogenic bone substitutes might provide similarly robust results as SH sites regarding the progression of experimental peri-implantitis, irrespective of the infected or noninfected nature of the site before tooth extraction.