Influence of different treatment approaches on non-submerged and submerged healing of ligature induced peri-implantitis lesions: an experimental study in dogs

Objective: The aim of the present study was to evaluate non-submerged and submerged healing of ligature induced peri-implantitis in dogs. Material and Methods: Peri-implantitis was induced by ligature placement in five beagle dogs (n=30 implants). The defects were randomly and equally allocated in a split-mouth design to either closed treatment+non-submerged healing (CNS), or open treatment+submerged healing (OS) using an Er:YAG laser (ERL), an ultrasonic device (VUS), or plastic curettes+local application of metronidazole gel (PCM), respectively. The animals were sacrificed after 3 months. Clinical, radiological and histological (e.g. new bone-to-implant contact (BIC)) parameters were assessed. Results: All treatment procedures resulted in statistically significant improvements of all clinical parameters at both CNS and OS implants. Radiological improvements were merely observed at OS implants. Histomorphometrical analysis revealed that all CNS implants exhibited comparable low amounts of new BIC (1.0-1.2%), while mean BIC was statistically significant higher in the respective OS groups [ERL (44.8%), PCM (14.8%), VUS (8.7%)]. Conclusion: Within the limits of the present study, it was concluded that (i) OS improved the outcome of treatment in comparison with CNS and (ii) ERL seemed to be more suitable to promote re-osseointegration than PCM and VUS.