This thesis is focused on (I) the outcome of reconstructive treatment of peri-implant defects and (II) risk factors for the development of peri-implantitis.

Background

An increasing number of individuals have dental implant-supported reconstructions. The long-time survival rate of dental implants is good, but complications do occur. Accumulation of bacteria on oral implants and the development of a pathogenic biofilm at the mucosal margin will result in inflammatory responses diagnosed as peri-implant mucositis(PiM). Furthermore, PiM may progress to peri-implantitis (Pi) involving the implant-supporting bone and potentially result in a severe inflammatory process resulting in alveolar bone destruction and consequently implantloss. Currently, Pi is a common clinical complication following implant therapy.The prevalence of peri-implantitis has been reported to be around 20 %. Susceptibility to infections and a history of periodontitis are considered as important risk indicators for peri-implantitis. It seems logical that a past history of periodontitis is linked to an increased risk of peri-implantitis. It is possible that other patient-associated factors such as a smoking habit, and presence of general diseases may also be linked to a higher risk for developing peri-implantitis.Treatment of peri-implantitis is difficult. Non-surgical treatment modalities may not be sufficient to resolve the inflammatory process to obtain healthy conditions.Surgical treatment of peri-implantitis has commonly been employed in clinical practice to obtain access to the implant surface thereby increasing the possibility to effectively decontaminate the implant surfaces.The effectiveness and long-term outcomes of reconstructive surgical treatments of peri-implantitis has been debated. The scientific evidence suggests that regular supportive care is an essential component in order to maintain and secure long-term results following treatment of peri-implantitis.

Aims

1. To assess the short-term efficacy of reconstructive surgical treatmentof peri-implantitis  (Study I).

2. To analyse risk factors related to the occurrence of peri-implantitis(Study II).

3. To assess the importance of defect configuration on the healing response after reconstructive surgical therapy of peri-implantitis (Study III).

4. To assess the long-term efficacy of reconstructive surgical treatmentof peri-implantitis (Study IV).

MethodsFour studies were designed to fulfil the aims:

- A single-blinded prospective randomised controlled longitudinal human clinical trial evaluating the clinical and radiographic results of reconstructive surgical treatment of peri-implantitis defects usingeither AB or BDX.

- A retrospective analysis of individuals with either peri-implantitis, or presenting with either peri-implant health, or peri-implant mucositis assessing the likelihood that peri-implantitis was associated with a history of systemic disease, a history of periodontitis, and smoking.

- A prospective study evaluating if the alveolar bone defect configuration at dental implants diagnosed with peri-implantitisis related to clinical parameters at the time of surgical intervention and if the short- and long-term outcome of surgical intervention of peri-implantitis is dependent on defect configuration at the time of treatment.

- A prospective 5-year follow-up of patients treated either with AB or BDX.

Results

- The success for both surgical reconstructive procedures was limited. Nevertheless, bovine xenograft provided evidence of more radiographic bone fill than AB. Improvements in PD, BOP, and SUP were observed for both treatment modalities

-In relation to a diagnosis of peri-implantitis, a high likelihood of comorbidity was expressed in the presence of a history of periodontitis and a medical history of cardiovascular disease

- The buccal-lingual width of the alveolar bone crest was explanatory to defect configuration

- 4-wall defects and deeper defects demonstrated more radiographic evidence of defect fill

- Reconstructive surgical treatment of peri-implant defects may result in successful clinical outcomes, that can be maintained over at least five years

- The use of BDX is more predictable than use of harvested bone from the patient (AB)

Conclusions

The study results suggest that a bovine xenograft provides better radiographic evidence of defect fill than the use of autogenous bone harvested from cortical autologous bone grafts.Treatment with bone grafts to obtain radiographic evidence of defect fill is more predictable at 3- and 4-wall defects than at peri-implantitis bone defects with fewer bone walls.In relation to a diagnosis of peri-implantitis, a high likelihood of comorbidity was found for a history of periodontitis and a history of cardiovascular disease.