Influence of defect morphology on the therapeutic outcomes of peri-implantitis

Peri-implant bone defect morphology is widely regarded as clinically relevant in the management of peri-implantitis, but its actual influence on treatment outcomes remains unclear. The aim of this review was to assess how peri-implant defect morphology has been defined, assessed, and analyzed in relation to the clinical, radiographic, and disease resolution outcomes following peri-implantitis treatment.

A systematic review was performed including human clinical studies on nonsurgical and/or surgical peri-implantitis treatment that reported peri-implant defect morphology, included at least 10 treated implants, evaluated outcomes at a minimum of two time points, and presented at least 12 months of follow-up. Extracted data focused on morphology definitions and assessment methods, treatment characteristics, and morphology-related analyses of treatment outcomes. The primary outcome was the influence of peri-implant defect morphology on clinical, radiographic, and disease-resolution outcomes following peri-implantitis treatment.

Thirty-five studies were included in the qualitative synthesis. Marked heterogeneity was observed across study design, peri-implantitis definitions, morphology descriptions, therapeutic protocols, and outcome measures. Morphology was assessed mainly by periapical radiographs and intra-surgical evaluation, whereas three-dimensional imaging was uncommon and rarely used for baseline defect characterization. Although all included studies reported morphology to a degree sufficient for eligibility, only a minority incorporated it into analytical models, subgroup comparisons, regression analyses, or morphology-stratified outcome interpretation. When morphology was analyzed and reported, the approaches were inconsistent in describing the features of the peri-implantitis-related bone defects and included formal classifications, wall configuration, intrabony component, defect depth, defect width, defect angle, and/or number and location of missing walls. Some studies suggested more favorable outcomes in contained or circumferential defects and in narrower-angle defects, particularly for radiographic fill or bone gain when non-resective measures were carried out, but these findings were not consistent across investigations and were less evident for disease resolution.

Defect morphology represents a key driver in selecting the therapeutic modality to manage peri-implantitis and in anticipating the degree of therapeutic response. However, the available evidence is limited by substantial heterogeneity in peri-implantitis definitions, morphology assessment methods, treatment protocols, outcome measures, and disease-resolution criteria, and only a minority of studies incorporated morphology into analytical models or subgroup comparisons capable of clarifying whether it truly modifies prognosis or treatment response. In general, the literature fails in assigning accurately morphological features to peri-implantitis-related bone defects, other than the number of residual walls.

Peri-implantitis-related bone configuration deserves careful consideration as part of the overall assessment of peri-implantitis lesions, but current evidence does not yet support its use as a robust independent prognostic or treatment-modifying variable.