Influence of Zirconia Abutments on Peri-Implant Tissues in Single-Tooth Restorations

Objectives: To compare the influence of pre-fabricated titanium abutments and customized milled zirconia abutments on implant biocompatibility and the peri-implant region, as well as on radiographic bone loss and oral health-related quality of life. Detailed Methodology: This study is a randomized controlled clinical trial designed to evaluate the biological and clinical behavior of standardized titanium abutments compared with customized anatomical zirconia abutments in single implant-supported posterior restorations. The present investigation represents the prosthetic phase of a previously conducted randomized clinical trial that evaluated dimensional changes following different alveolar preservation protocols in posterior regions (CAAE: 59208422.8.0000.5418). In the previous phase, participants underwent tooth extraction and alveolar preservation procedures, followed by implant placement with Morse Taper (CM) implants (Biomorse XP, Bionnovation Biomedical) after a six-month healing period. After implant osseointegration, participants eligible for prosthetic rehabilitation will be randomly allocated to one of two parallel groups using a computer-generated randomization sequence (Sealedenvelope.com). The allocation ratio will be 1:1. Sample size calculation was performed using GPower software to ensure adequate statistical power. The intervention consists of prosthetic rehabilitation with either standardized titanium abutments (TiB group) or customized anatomical zirconia abutments (ZiT group), both supporting single zirconia crowns in posterior regions. All prosthetic and laboratory procedures will follow standardized clinical protocols. Clinical and laboratory assessments will be conducted at prosthesis delivery (baseline) and at 1-, 3-, 6-, and 12-month follow-up visits. Data collection will include peri-implant crevicular fluid (PICF) and biofilm sampling for biomolecular analysis, comprehensive periodontal clinical parameters, measurement of keratinized mucosa thickness, standardized periapical radiographs for marginal bone level assessment, and intraoral digital scanning for volumetric and soft tissue analysis. The primary objective is to compare peri-implant tissue stability and biological response between titanium and zirconia abutments. Secondary outcomes include clinical parameters, marginal bone level changes, and soft tissue dimensional stability over a 12-month follow-up period. This study aims to contribute to the understanding of how abutment material and design may influence peri-implant health and long-term tissue stability in posterior implant-supported restorations.