Comparison of a Hydroxyapatite-Coated and an Anodic Oxidized Titanium Implant for Experimentally Induced Peri-Implantitis: Macroscopic and Novel Radiographic Evaluations in a Canine Model

Abstract

This study aimed to compare the response of peri-implant tissue surrounding hydroxyapatite-coated titanium (HA) implants and anodic oxidized titanium (AnO) implants, as well as associated ligature-induced peri-implantitis. The third and fourth premolars (P3, P4) of the mandible were extracted in five beagle dogs. After 2 months, 10 dental implants with different surfaces (HA/AnO) were inserted into the mandible in five beagle dogs. A plaque control program was maintained until the second-stage surgery. Three months after implantation, a healing-cap connection was performed, and silk ligatures were placed in the submarginal position around the neck of the implants to induce peri-implantitis. Macroscopic evaluations including modified plaque index (mPI), modified gingival index (mGI), and probing depth (PD), and radiographic evaluations including dental radiography and multislice computed tomography (MSCT) were conducted for 24 weeks following ligature placement. Bone loss around the implant was evaluated according to the radiolucent area on dental radiographic images and the hyperpermeability area on MSCT images. All macroscopic parameters except PD exhibited a consistent increase for all implants. Over the course of the study, bone loss associated with the HA implant was greater than losses with the AnO implant. Following evaluation of dental radiographs at 20 and 24 weeks after ligature placement, a significant difference was detected between the HA and AnO implants (P < 0.05). The results suggested that the resistance of the HA implant to peri-implantitis was inferior to that of the AnO implant.