Effects of Different Loading Protocols on the Bone Remodeling Volume of Immediate Maxillary Single Implants: A 2- to 3-year Follow-up

Purpose: The purpose of this study was to assess the effect of different loading protocols (immediate or delayed) on bone volume remodeling of an immediate implant-supported single crown in the maxilla with a follow-up from 2 to 3 years. Materials and Methods: Patients presenting a failing tooth were rehabilitated with implant-supported single crowns. Data of patients with a survey from 2 to 3 years after baseline surgery were retrospectively acquired. One implant per patient was randomly selected during data analysis and assigned to one of two predictor groups: the loading protocol, 9 immediate vs 13 delayed loading; and tooth position, 9 incisors vs 9 canines. Cumulative survival rates were recorded; loss of crestal bone volume was assessed with cone beam computed tomography (CBCT) by means of software that superimposed the preoperative and postoperative CBCT scan data (Matrix Laboratory) and by dentascan software. Results: Twenty-two patients were enrolled. No postoperative complications or implant failures were recorded. Bone volume loss from the 2- to 3-year follow-up period ranged between 19.1% and 22.0%, without significant differences between the two loading protocols. Irrespective of the tooth site, intragroup analyses revealed the presence of significant differences between preoperative and postoperative time evaluations for all the analyzed groups and subgroups. Volumes at baseline (ranging between 0.546 and 0.553 mL) recorded significant loss of approximately 110 mm3 (P values ≤ .0001) for both loading protocols. The volume at the postoperative evaluation ranged between 0.428 and 0.442 cm3. Considering tooth site in the analysis, the subgroups showed similar behaviors at the crestal bone level. However, bone loss at the apex of the implant appeared to be lower for incisors than canines. Conclusion: This study attested that the loss of crestal bone around an immediate implant-supported single crown depended on neither the loading protocol nor the tooth site. Keywords: cone beam computed tomography imaging, extraction socket, fixed implant prosthesis, immediate loading, immediate placement