Early intervention of peri‐implantitis and periodontitis using a mouse model

1 Background

Peri‐implantitis is an inflammatory response to bacterial biofilm resulting in bone loss and can ultimately lead to implant failure. Because of the lack of predictable treatments available, a thorough understanding of peri‐implantitis's pathogenesis is essential. The objective of this study is to evaluate and compare the response of acute induced peri‐implantitis and periodontitis lesions after insult removal.

2 Methods

Implants were placed in one‐month‐old C57BL/6J male mice eight weeks post extraction of their left maxillary molars. Once osseointegrated, ligatures were placed around the implants and contralateral second molars of the experimental groups. Controls did not receive ligatures. After one week, half of the ligatures were removed, creating the ligature‐retained and ligature‐removed groups. Mice were sacrificed at two time points, 5 and 14 days, from ligature removal. The specimens were analyzed via micro‐computed tomography and histology.

3 Results

By 5 and 14 days after ligature removal, the periodontitis group experienced significant bone gain, whereas the peri‐implantitis group did not. Histologically, all implant groups exhibited higher levels of cellular infiltrate than any of the tooth groups. Osteoclast numbers increased in peri‐implantitis and periodontitis ligature‐retained groups and decreased following insult removal. Collagen was overall more disorganized in peri‐implantitis than periodontitis for all groups. Peri‐implantitis experimental groups revealed greater matrix metalloproteinase‐8 and NF‐kB levels than periodontitis.

4 Conclusions

Implants respond slower and less favorably to insult removal than teeth. Future research is needed to characterize detailed peri‐implantitis disease pathophysiology.     

Epidemiology and risk factors of peri‐implantitis: A systematic review

The purpose of this systematic review and meta‐analysis was to assess the prevalence, incidence and risk factors of peri‐implantitis in the current literature. An electronic search was performed to identify publications from January 1980 until March 2016 on 9 databases. The prevalence and incidence of peri‐implantitis were assessed in different subgroups of patients and the prevalences were adjusted for sample size (SSA) of studies. For 12 of 111 identified putative risk factors and risk indicators, forest plots were created. Heterogeneity analysis and random effect meta‐analysis were performed for selected potential risk factors of peri‐implantitis. The search retrieved 8357 potentially relevant studies. Fifty‐seven studies were included in the systematic review. Overall, the prevalence of peri‐implantitis on implant level ranged from 1.1% to 85.0% and the incidence from 0.4% within 3 years, to 43.9% within 5 years, respectively. The median prevalence of peri‐implantitis was 9.0% (SSA 10.9%) for regular participants of a prophylaxis program, 18.8% (SSA 8.8%) for patients without regular preventive maintenance, 11.0% (SSA 7.4%) for non‐smokers, 7.0% (SSA 7.0%) among patients representing the general population, 9.6% (SSA 9.6%) for patients provided with fixed partial dentures, 14.3% (SSA 9.8%) for subjects with a history of periodontitis, 26.0% (SSA 28.8%) for patients with implant function time ≥5 years and 21.2% (SSA 38.4%) for ≥10 years. On a medium and medium‐high level of evidence, smoking (effect summary OR 1.7, 95% CI 1.25‐2.3), diabetes mellitus (effect summary OR 2.5; 95% CI 1.4‐4.5), lack of prophylaxis and history or presence of periodontitis were identified as risk factors of peri‐implantitis. There is medium‐high evidence that patient’s age (effect summary OR 1.0, 95% CI 0.87‐1.16), gender and maxillary implants are not related to peri‐implantitis. Currently, there is no convincing or low evidence available that identifies osteoporosis, absence of keratinized mucosa, implant surface characteristics or edentulism as risk factors for peri‐implantitis. Based on the data analyzed in this systematic review, insufficient high‐quality evidence is available to the research question. Future studies of prospective, randomized and controlled type including sufficient sample sizes are needed. The application of consistent diagnostic criteria (eg, according to the latest definition by the European Workshop on Periodontology) is particularly important. Very few studies evaluated the incidence of peri‐implantitis; however, this study design may contribute to examine further the potential risk factors.