Immediate Maxillary Restoration of Single-Tooth Implants Using Platform Switching for Crestal Bone Preservation: A 12-Month Study

Purpose: The aim of this prospective clinical study was to evaluate the survival rates at 12 months of a new implant design placed in the anterior and premolar areas of the maxilla and immediately restored with single crowns. Crestal bone loss was also assessed. Materials and Methods: Patients seeking replacement of at least one failing maxillary tooth were recruited to participate in the study. Exclusion criteria included compromised general health conditions, severe maxillomandibular skeletal discrepancies, severe parafunctional habits, drug or alcohol abuse, poor oral hygiene, and a need for bone augmentation. Implants incorporating the platform-switching concept were placed into fresh extraction sockets in the maxilla, with each patient receiving a provisional restoration immediately after implant placement. After 15 days, definitive restorations were inserted. Mesial and distal bone levels were evaluated with digital radiography on the day after implant placement, 15 days later, and 1, 2, 3, 6, 8, and 12 months later. Primary stability was measured with resonance frequency analysis (RFA). Analysis of variance for repeated measures and a binary logistic regression model were used to assess the data. Results: Sixty-one implants were placed into fresh extraction sites in 25 men and 25 women ranging in age from 29 to 51 years (mean, 39.64 ± 6.06 years). One of the implants failed, and one was lost to follow-up. The mean bone loss measured on the mesial was 0.08 mm (SD 0.53 mm). Mean distal bone loss was 0.09 mm (SD 0.65 mm). Over the course of 12 months, the mean RFA value between baseline and 12 months was 71.1 ± 6.2. Conclusions: The implants remained stable over the course of 12 months and had an overall survival rate of 96.7%. Minimal crestal bone loss was recorded around the surviving implants. Keywords: immediate provisionalization, platform switching, resonance frequency analysis