Spontaneous progression of experimental peri-implantitis at implants with different surface characteristics: An experimental study in dogs

Aim: To analyse spontaneous progression of ligature-induced peri-implantitis at implants with different surface characteristics. Material and Methods: Four implants with similar geometry and with two different surface characteristics (turned/TiUnite; Nobel Biocare AB) were placed pairwise in one side of the mandible in five dogs, 3 months after tooth extraction. Experimental peri-implantitis was initiated by placement of ligatures and plaque formation. The ligatures were removed when about 40% of the supporting bone was lost. After 6 months, block biopsies were obtained and prepared for histological analysis. Results: The amount of bone loss that occurred during the plaque accumulation period after ligature removal was significantly larger at implants with a TiUnite surface than at implants with a turned surface. The histological analysis revealed that the vertical dimensions of the lesion and the pocket epithelium and the apical extension of the biofilm were significantly larger at TiUnite implants than at turned implants. Conclusion: It is suggested that the implant surface characteristics influence progression of peri-implantitis.