Clinical and radiographic performance of delayed-immediate single-tooth implant placement associated with peri-implant bone defects. A 2-year prospective, controlled, randomized follow-up report

Objectives: The aim of the present study was to compare the delayed‐immediate (Im) and the delayed (De) protocols for placement of single‐tooth implants. Material and methods: After allocation to the Im and De groups by random, 46 patients were treated with a single‐tooth implant with acid etched surfaces (Osseotite^®) in the anterior or pre‐molar region of the maxilla or the mandible on average 10 days (Im) or 3 months (De) following tooth extraction, respectively. Forty‐one patients attended a follow‐up visit 2 years after implant placement corresponding to 1½ years of loading of the implant restorations. Peri‐implant and prosthetic parameters were evaluated clinically and marginal bone levels measured on radiographs. Results: Three implants were lost, all before mounting of the crown. None of the implant restorations had failed after 1½ years of function. Probing pocket depths were reduced by up to 1.4 mm on average from the time of loading to the 2‐year follow‐up and at that time, no significant difference between the Im and De groups was found (4.2 versus 4.1 mm). A statistically significant radiographic marginal bone loss had occurred in the Im group (mean=0.8 mm) as well as in the De group (mean=0.7 mm) in the follow‐up period. However, a mean marginal bone level of approx. 1.5 mm in both groups measured from the implant–abutment junction was found to be acceptable. It was demonstrated that probing pocket depths and marginal bone levels after 1½ years of loading of the implant‐retained crowns were not influenced by the presence of peri‐implant bone defects immediately after implant placement. Furthermore, no severe prosthodontic complications, such as screw loosening or porcelain fractures, arose in this study material. Conclusion: High success rates of single‐tooth implants after 1½ years of function were achieved using the delayed‐immediate and delayed implant placement techniques.