University of Southern Denmark Long-term radiographic assessment of titanium implants installed in maxillary areas grafted with autogenous bone blocks using two predefined sets of success criteria Fuglsig,

Purpose: Assess the radiographic peri-implant bone loss of implants installed in maxillary areas grafted with autogenous bone and classify the long-term (at least >4≤6 years) implant success according to two predefined sets of criteria. Material and methods: Sixty patients had full maxillary alveolar reconstructions using autogenous bone grafts (iliac crest), and 369 titanium implants were installed. The followup protocol was five (>4≤6) years; thereafter only patients, who presented significant periimplant bone loss were followed up to 12 years. Radiographic peri-implant bone level was assessed on panoramic radiographs in relation to the baseline, and used to classify the long-term success of the implants according to the predefined success criteria presented by Albrektsson and coworkers/ALB (1986) and the Pisa Consensus Conference/PCC (2007). Results: Fifteen implants were lost over the 12-year follow-up period (two up to >4≤6 years). Mean radiographic peri-implant bone loss was 2.7 mm at the >4≤6 years control, and 4.2 mm after >11≤12 years. Different success criteria resulted in different prevalences of implants classified as “failures”. At >4≤6 years, 48% of the implants would be “failures” This article is protected by copyright. All rights reserved. according to ALB, while according to the PCC, only 0.8% would be “failures”, and 18.1% would be classified as “compromised survival”, and 44.8% as “satisfactory survival”. Conclusions: Mean peri-implant bone loss of implants installed in maxillary areas grafted with autogenous bone blocks was 2.7 mm after >4≤6 years, and two implants were lost during this period. The use of different success criteria significantly altered the prevalence of implants classified as “failure”. Introduction Edentulism has for many decades been treated with teethor mucosa-supported prostheses, though in recent decades the use of implant-supported prostheses has become a more common and accessible solution. However, the fact that resorption of the dentoalveolar bone occurs following tooth loss may present an immediate challenge to the implant-supported rehabilitation. If bone resorption is pronounced, the lack of alveolar bone could complicate or make it impossible to anchor the implants. To overcome this challenge, various bone grafting procedures have been suggested in order to obtain an adequate bone volume for the installation of implants. The use of autogenous bone grafts (e.g. retrieved from the iliac bone) is well-established as the gold standard technique for grafting procedures due to their osteoconductive, osteoinductive, and osteogenic characteristics. Some drawbacks, however, are related to this technique: post-surgical pain, risk of paresthesia, and limitations in the quality and quantity of available bone. In any case, for major reconstruction procedures, the iliac bone has This article is protected by copyright. All rights reserved. been found to be a suitable donor site both from the anterior and posterior crista with relatively easy access to large amounts of cortico-cancellous bone. The success of implants placed in grafted areas has been a subject undergoing intense investigation for decades, however, as shown in recent systematic reviews the use of predefined success criteria is not an established routine in clinical studies on the topic. Success criteria have been proposed by various research teams, while the best established classification (and thus most commonly used) is that of Albrektsson and coworkers (ALB), which summarizes implant conditions in a dichotomous manner: “success” or “failure”. The ALB classification is based on the assessment of implant survival, implant mobility, presence of infection, presence of pain, and peri-implant bone loss (assessed by means of clinical probing and/or radiographic evaluation), considering the time in years after the implant was installed. Alternative criteria were presented by the Pisa Consensus Conference (PCC) in 2007, which focused on the same parameters, but defined the acceptable peri-implant bone loss as a parameter, which is not dependent on the number of years that an implant has been in function. The PCC criteria abandoned the dichotomous labeling of the implant condition and focused on a more “clinically feasible” situation, by classifying the implant as “successful”, “satisfactory survival”, “compromised survival”, or “failure”. However, at the moment this classification system is not well incorporated into the literature. Thus, the aim of this study was to assess the radiographic peri-implant bone loss of implants installed in maxillary areas grafted with autogenous bone blocks combined with maxillary sinus lift using particulate bone mixed with heterogeneous bone substitute material, in a two-stage procedure, up to 12 years after implant placement. Further, the This article is protected by copyright. All rights reserved. measurements of bone loss were used to classify the long-term (at least >4≤6 years) success of the implants according to the criteria defined by ALB and PCC. Materials and Methods