Peri-Implant Infection – A modern Phenomenon or a Long-Ignored Problem?

by Dr. Hendrik Doering, DDS

Replacing lost teeth by artificial tooth roots (implants) in combination with artificial dental crowns has become part of mainstream dentistry and is now regarded as a routine procedure with predictable results. Over the past 30 years, the number of implants placed in the jaws constantly increased promoting development of new materials and techniques based on collective clinical experience and higher expectations of our patients. Nowadays survival rates of more than 95% are routinely achieved.1-4 Nevertheless, with the number of implants inserted and practitioners who place them, we are witnessing a number of complications of concern. Only recently did the scientific community pay more attention to peri-implant diseases. In 2000, only 26 articles under the keyword of “peri-implantitis” were identified by search with PUBMED. This number rose to 192 in 2012, suggesting a heightened interest in the field. Most of the studies identified the maintenance of implant surrounding soft tissues as an important preventive factor.5,6 Similar to dental caries, gingivitis and periodontal diseases, the primary goal in preserving peri-implant health is the regular and systematic removal of bacterial plaque/biofilm. Furthermore, the data has shown that peri-implant infections are often responsible for late failures. Therefore, early detection and timely treatment is an important part of routine monitoring of implants. A distinction is made between “peri-implant mucositis” and “peri-implantitis”.7 The first refers to a completely reversible inflammation of the peri-implant soft tissues. Progressive accumulation of plaque and sustained submarginal inflammation leads to progressive bone loss around the implant and is referred to as peri-implantitis. The development of peri-implantitis does not inevitably leads to implant failure.

It appears that the main causative factors of peri-implant diseases are bacterial infections, biomechanical overload or a combination of both. Plaques forming bacteria or their constituents are the cause of bacterial infections. The infection may originate from extra-oral sources (transition from contacts or the environment) or more often is derived from existing periodontal pockets, saliva, surface of the tongue, tonsils or oral mucosa.8 The remaining teeth and their periodontal condition must be regarded as the most important source of pathogenic bacteria in the peri-implant microflora. It is very likely that individuals susceptible to chronic periodontitis are at higher risk of peri-implantitis. Hence, pre-existing periodontal disease and poor oral hygiene clearly put patients at higher risk of peri-implant disease. A combination of active smoking and poor oral hygiene has emerged as the most important factor for peri-implant bone loss.8

Only few studies provide data about the prevalence of peri-implant diseases. Two major studies showed the occurrence of prei-implant mucositis in 80 percent of the subjects and in 50 percent of the implant sites. Peri-implantitis was identified in 28 percent of the subjects and in 12 percent of implant sites.7 The high prevalence underscores dentists’ duty to take precautions for reducing the know risk factors before implant treatment and educate the patient about the possible risks of peri-implant infections.

Similar to periodontal diseases, the successful treatments of peri-implant diseases are less labour intensive and more predictable in the early stages. Hence early and accurate diagnosis is of importance.9 Early detection of irreversible peri-implantitis is accomplished by means of regular and long-term follow-up and charting. Peri-implant soft tissue inflammation (mucositis) is an indication of insufficient hygiene. This is characterized by a combination of redness, edematous change, bleeding with gentle probing and slightly increased probing depth.9 At this stage there is no significant increase in probing depth or peri-implant attachment loss. With progressive inflammation a loss of attachment and radiographically detectable bone loss occurs. Clinical symptoms, such as increased probing depth (relative to baseline), bleeding on gentle probing, pus discharge from the pockets and often dull deep set pain can be regarded as alarming symptoms of peri-implantitis.9,10 The radiological evaluation of peri-implant bone levels is an important diagnostic tool to detect a peri-implant bone loss and its progression by comparing serial films. A microbiological analysis of submarginal microflora before and after antimicrobial therapy might help to assess the success or end point of various treatment modalities.

Various treatment options have been proposed, evaluated and assessed for efficacy in the specialty literature. So far no universally accepted modality has emerged. Hence, each case has to be evaluated individually. Non-surgical therapy shows promising results in early states of an inflammation, especially the mechanical cleaning of the infected site in combination with antimicrobial mouth rinses (e.g. Chlorhexidine).11,12 For later stages of the inflammation with progressive bone loss, the non-surgical therapy proved to be ineffective. Surgical therapy was addressed in various studies.13 Unfortunately, to date, these studies lack in design and power and failed to give us clear treatment directions. Clearly the exposure of the implant surface is an undesirable consequence of peri-implant disease. The decontamination of this plaque-attracting surface is a central goal of the treatment. It is clear that the lack of effective methods for decontamination of often three-dimensional surfaces is crucial to create conditions for soft tissue reattachment or peri-implant bone regeneration (chemical agents, topically applied antibiotics, air abrasives and lasers have all been tired). Recently a number of rotating brushes have been developed to increase the efficacy of debridement efforts of the exposed implant surfaces (TiBrush Strauman®PeriBrush™ Tigran Technologies AB; i-Brush, Hubermed; RotoBrush-Salvin). Their efficacy remains to be proven. Also it is not know if the use of systemically administered antibiotics have a positive and essential effect on the outcome of treatment. The term of “re-osseointegration” has been widely discussed as well and should be differentiated from regeneration of lost peri-implant bone around integrated implants. So far there is little evidence to support “reosseointegration” as a viable treatment outcome.

Recent literature has shown that peri-implant diseases are not just a “modern phenomenon” but an aspect that was ignored due to the relative “blindness” created by the novelty of and high predictability of dental implants. Although our knowledge of the etiology of the peri-implant diseases and the modalities of treatment can be best characterized by “work in progress” we know far more about the predisposing risk factors. Therefore it is crucial that dentists as well as hygienists concentrate on reducing the known risk factors before placement of implants and are aware of the early indicators of an ongoing inflammation. Diagnostic acumen will lead to a much-preferred early intervention. What is still unclear is the rate of progression and the determinants of the peri-implant diseases. Such knowledge may prove to be crucial in telling us when to initiate treatment and at what level of complexity.

The education and instruction of patients in implant maintenance and daily homecare are of paramount importance for a successful implant treatment.14

Researchers as well as the implant manufacturing industry often react first to promising results with new materials, new implants and abutment designs.15 The field of peri-implant diseases has become a focus in research. Our unde
rstanding of etiology and relationships between the different peri-implant tissues is likely to improve in the near future. Although our understanding of the peri-implant diseases is improving it still remains a considerable challenge for our everyday practice.OH

1. Department of Oral and Maxillofacial Surgery, University Hospital Erlangen, Erlangen, Germany

2. Department of Periodontology, Faculty of Dentistry, University of Toronto, ON. Canada

Oral Health welcomes this original article.

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