Successfully treating peri-implantitis – is that possible?

Implants have long established themselves as a standard procedure. Both patients and practitioners appreciate their value and the ability to reliably restore edentulous areas of the jaw. New implant surfaces allow for use even in compromised situations with shorter healing times. It seems that there is no risk. Survival rates significantly above 95% are taken for granted. Is it really that simple? Is the implant a low-risk means for treatment in everyday dentistry? Survival rates are not the same as success. Studies suggest that up to 65% of cases are affected by peri-implant mucositis and 47% by peri-implantitis. Early treatment of peri-implant mucositis and prevention of peri-implantitis is of utmost priority.

In recent years, the use, as well as patient demand for dental implants, has increased significantly. The ability to replace single missing teeth or solve difficult prosthetic situations has gained new dimensions through the use of implants. Today, implants are used as anchoring elements for fixed and removable dentures.

Biological complications of implants can be classified into peri-implant mucositis and peri-implantitis. Peri-implant mucositis is defined as inflammation without bone loss/reduced bone level. The existing inflammation affects the mucosa adjacent to the implant, whereas in the case of peri-implantitis, the inflammation is combined with bone loss.

Peri-implant diseases are similar in their definition and course to periodontal diseases. Here, a bacterial disease of the tooth bed (periodontium) with deep gum pockets and increasing bone loss ultimately leads to the loss of the tooth. Several possible risk factors are discussed for the development of peri-implantitis. These range from the absence of attached/keratinized gingiva and roughness of the implant surface to pre-existing periodontal diseases. A positive smoking history or the type of prosthetic restoration of the implants could also increase the risk of developing peri-implantitis.

The etiological factor is referred to as "plaque." Similar to gingivitis, which represents an inflammation of the marginal oral mucosa, plaque leads to mucositis. It is believed that some, but not all, mucosal changes progress to peri-implantitis.

Diagnostics

For the diagnosis of peri-implant mucositis and peri-implantitis, only a periodontal probe and a single tooth radiograph are necessary. Regular probing of the peri-implant probing depths after the healing phase is recommended. The pressure should not exceed 0.25 N. The concern of damaging the implant surface during the probing process is unfounded, so conventional measuring probes do not need to be replaced by special measuring probes. Early detection of peri-implant mucositis is important, as the transition to peri-implantitis is gradual, and currently, no available tools can determine the stage of the disease. In addition to probing depths, Bleeding on Probing (BoP) is a focus, which gives the practitioner an initial insight into the inflammatory condition of the mucosa. While a positive BoP indicates at least peri-implant mucositis, suppuration is a sign of existing peri-implantitis.

For bone loss, literature indicates thresholds between 0.4 and 5 mm at which peri-implantitis can be diagnosed. There are also cases reported where a bone loss of up to three screw threads was not considered peri-implantitis but still fell within the definition of peri-implant mucositis. These bony remodeling processes can only be recognized in X-rays and can be evaluated depending on the type of imaging taken. The single tooth film, which is taken in a right-angle technique, is generally recommended here. To better assess the remodeling processes, it is advised to obtain an X-ray image in addition to a probing finding at the time of the insertion of the dental prosthesis (DP). This allows for a better comparison of the initial situation with any resorption events that may occur later. Not every loss of bone around implants is equivalent to peri-implantitis. Rather, physiological remodeling processes after DP provision can also lead to bone loss.

Prevalence and Risk Factors

A systematic overview of the epidemiology of peri-implant health and diseases from 2015 dealt with post-implant complications. The prevalence of peri-implant mucositis and peri-implantitis ranged, depending on the case definitions used, from 19 to 65% and from 1 to 47%. In subsequent meta-analyses, the mean prevalence for peri-implant mucositis was estimated at 43% (CI: 32–54%) and for peri-implantitis at 22% (CI: 14–30%).

General Risk Factors

Since peri-implantitis is attributed to bacterial "plaque," the ability of plaque to adhere to the implant surface is of great importance. This varies depending on the surface characteristics. It has been demonstrated that less biofilm adheres to smooth implant surfaces. Furthermore, preclinical studies have shown that bone loss in implants with polished surfaces was significantly lower compared to rough surfaces.

Smoking is considered a significantly influencing risk factor for the development of peri-implantitis. Many studies have investigated this factor and found a clear increase in the prevalence of peri-implantitis with a positive smoking history. In another study, such a correlation could not be observed. Accordingly, statements about prevalence-increasing factors depend on the patient cohorts studied. Nevertheless, a systematic literature review describes a significant correlation between smoking and peri-implant complication rates. Whether the absence or presence of attached/keratinized gingiva plays a role as another risk factor for the development of peri-implant diseases is scientifically controversially discussed. There is one study in which no significant association between attached gingiva and peri-implantitis could be demonstrated. In another study, however, an increased risk for both mucositis and peri-implantitis was found in the presence of attached/keratinized gingiva. However, there are currently no evidence-based data confirming a correlation between the absence of keratinized mucosa and peri-implant inflammation. The type of prosthetic implant restorations, whether fixed or removable, and the so-called prosthetic misfit or "faulty superstructure" could also have an additional influence on peri-implant diseases. There are currently no scientific results for both factors. Additionally, the ability to maintain hygiene is discussed. Serino and Ström (2009) found that implants with non-cleanable superstructures were more frequently affected by peri-implantitis. Furthermore, there is a lack of scientific work that would demonstrate a possible correlation between the gender of patients and peri-implantitis. There are also only a few scientific studies on the effects of implant duration on the development of peri-implantitis. Nevertheless, the systematic review by Derks and Tomasi (2015) described a positive correlation between "implant age" and peri-implantitis prevalence.

Periodontitis as a Risk Factor

There are studies that include a patient collective that was not selected based on periodontal criteria. In one of these studies, the investigation was conducted on subjects whose periodontal status was unknown, and thus no conclusions could be drawn about the prevalence of peri-implant diseases in patients with periodontal preconditions. A multitude of studies include the periodontal health status in their findings, allowing for possible associations between peri-implant diseases and periodontitis to be established.

Marrone et al. (2013) showed that patients with active periodontitis are susceptible to the occurrence of peri-implantitis (OR = 1.98). Consequently, patient education regarding risks and regular follow-up care is recommended. Hardt et al. analyzed the remodeling of bone levels over a 5-year period in patients who were already predisposed to periodontal bone loss in a retrospective study conducted in 2002. For this purpose, the patient collective was divided into “Perio-subjects” and “Non-Perio-subjects.” It was found that patients who already exhibited periodontal bone destructions also developed greater bone loss around implants.

In a study by Rinke et al. (2011), the prevalence of peri-implant diseases in patients with partially dentate jaws was determined. A patient collective was formed through different inclusion and exclusion criteria, which was divided into several subject groups.

The inclusion and exclusion criteria were partially adopted from other studies. Patients were classified as smokers if they had a positive smoking history during the examination period or if they had quit smoking less than 5 years ago. This classification of smokers was taken from a study by Lang and Tonetti (2003). Patients who received periodontal therapy within 5 years prior to implantation were classified as subjects with "periodontal history." There was another patient classification that was adopted from a study by Eickholz et al. (2008). Patients were classified as "regular prophylaxis/SPT" (SPT = Suppurative Periodontal Treatment) if they adhered to the recommended intervals. If the intervals were exceeded by more than 100% (e.g., recommended SPT interval = 6 months, re-evaluation after 13 months), they were classified as "irregular prophylaxis/SPT."

Patients who suffered from aggressive periodontitis or did not participate in any post-therapeutic measures were excluded as subjects. All subjects received follow-up care corresponding to their findings.

Rinke et al. examined not only the evaluations between the occurrence of peri-implant diseases and other possible influencing factors, such as "smoking" and "compliance," but also the prevalence of peri-implantitis in periodontitis patients.

Rinke et al. could not demonstrate a significant association between periodontal diseases and peri-implant inflammation. Rinke et al. pointed out no significant association between periodontal diseases and peri-implant inflammation. Ferreira et al. (2006a), Koldsland et al. (2011), and Marrone et al. (2013) found a positive correlation between the presence of a periodontal disease and peri-implantitis. Mir-Mari et al. showed that the prevalence of peri-implantitis in patients of a private practice with periodontal follow-up treatment is comparable to the prevalence of peri-implantitis determined from university clinic patients.

Due to the differing results of past studies, future studies should continue to address the relationships between periodontitis and peri-implantitis.

Therapy

The early detection and subsequent treatment of peri-implant mucositis should be the primary goal in the prevention of peri-implantitis. Although the treatment of peri-implant mucositis does not lead to complete healing in all cases, it is more effective and cost-efficient for the patient, but should be monitored at short intervals of 3 months. The recommended therapy is limited to regular, systematic, and professionally conducted plaque removal and improving home oral hygiene. Additional aids such as rinses, ointments with various ingredients, antibiotics, or lasers have no additional benefit in the treatment of peri-implant mucositis. The elimination of possible causes should take priority. Smoking should be discontinued if possible, and the dental prosthesis should be checked for proper fit and corrected if necessary.

The therapy for peri-implantitis is divided into (1) non-surgical therapy and (2) surgical therapy.

While adjunctive measures have not provided additional benefits for peri-implant mucositis, they should be applied for the non-surgical therapy of peri-implantitis. In addition to the recommendation of powder-water jet devices with glycine powder, the Er:YAG laser also shows advantages regarding treatment success. Local antibiotics (doxycycline) and CHX chips can also be recommended as adjuncts. Even in the presence of peri-implantitis, the reduction of risk factors (inappropriate prosthetic restoration, smoking) should not be overlooked. If there is already bone destruction of more than 7 mm, stopping the progression (stable result for more than 6 months) through purely non-surgical therapy is unlikely. In these cases, early surgical therapy should be preferred. The importance of early detection and subsequent treatment of peri-implant mucositis is evident in the recommendations for surgical therapy of peri-implantitis. None of the examined surgical therapy approaches showed an advantage in direct comparison. There is consensus only that the granulation tissue should be completely removed and that cleaning the implant surface plays a central role. Whether mechanical or chemical cleaning should be preferred cannot yet be definitively stated at the current time. The defects that arise after cleaning can be filled with bone substitute material. Recessions are still very likely. The therapy makes it clear how important early detection and also the rapid treatment of peri-implant mucositis or already beginning peri-implantitis is. Progression can still be halted up to 7 mm of bone loss. Beyond 7 mm, the chances decrease significantly.

Outlook

Research in recent years clearly shows how differently the topics of peri-implant mucositis and peri-implantitis are defined and observed. However, it cannot be said that there is an uncontrollable wave of peri-implantitis, and fortunately, the concerns of previous years have not been confirmed. To provide more clarity for practitioners and to give them better protocols for the treatment of peri-implant mucositis and peri-implantitis, there is still a great need for research. Likewise, understanding related to implants and the surrounding inflammation must increase. Implantation is promoted as a simple and safe method to quickly provide edentulous jaw areas with fixed teeth. This is indeed the case; however, the conditions must be right to minimize subsequent interventions. Compared to other treatment methods, implants are still a relatively young field in dentistry. The change in materials, surface characteristics, the type of implant (single-piece, multi-piece), the abutment connection, whether the prosthesis is cemented or screwed, the prosthesis itself, the patient (smoker, diabetes, oral hygiene, etc.), and last but not least, the practitioner all influence the likelihood of peri-implantitis. We will have to wait and see whether newer ceramic implants or the treatment of peri-implant inflammation with probiotics will lead to a significant reduction in risk. It remains exciting.

Conclusion

Peri-implant mucositis is defined as inflammation without bone loss/reduced bone level. The present inflammation affects the mucosa adjacent to the implant, whereas in the case of peri-implantitis, the inflammation is combined with bone loss. The etiological factor is referred to as "plaque." Similar to gingivitis, which represents inflammation of the marginal oral mucosa, plaque leads to mucositis. It is assumed that some, but not all, mucosal changes may progress to peri-implantitis.

Diagnosis is made using a periodontal probe and an X-ray. Regular probing of the peri-implant probing depths after the healing phase is recommended. The pressure should not exceed 0.25 N. Furthermore, the Bleeding on Probing (BoP) should be assessed.

The prevalence of peri-implant mucositis and peri-implantitis reaches values in studies, depending on the case definitions used, ranging from 19 to 65% and from 1 to 47%. In subsequent meta-analyses, the mean prevalence for peri-implant mucositis was estimated at 43% (CI: 32–54%) and for peri-implantitis at 22% (CI: 14–30%).

It has been demonstrated that less biofilm adheres to smooth implant surfaces. A systematic literature review found a significant association between smoking and peri-implant complications. Whether the absence of attached/keratinized gingiva is a possible risk factor for the development of peri-implant diseases is scientifically controversially discussed. There are both studies that found no correlation between periodontitis and peri-implantitis, as well as studies that show a significant association between the two diseases. It is recommended to inform patients with periodontitis about the possible increased risk of developing peri-implantitis.

The early detection and subsequent treatment of peri-implant mucositis is the primary goal in the prevention of peri-implantitis. The recommended treatment for peri-implant mucositis is limited to regular, systematic, and professionally conducted plaque removal and improving home oral hygiene. While adjunctive measures have not provided additional benefits for peri-implant mucositis, they should be applied for the non-surgical treatment of peri-implantitis. In addition to the recommendation of powder-water jet devices with glycine powder, the Er:YAG laser or local antibiotics (doxycycline) and CHX chips also show advantages regarding treatment success. If there is already bone destruction of more than 7 mm, stopping the progression (stable result for more than 6 months) through purely non-surgical therapy is unlikely. In these cases, early surgical therapy should be preferred. Regardless of the various surgical methods, there is consensus that granulation tissue should be completely removed and the cleaning of the implant surface plays a central role. Both in the treatment of peri-implant mucositis and peri-implantitis, the reduction of risk factors should not be overlooked.

There is still a great need for research in the future to continuously reduce the prevalence rates of peri-implantitis, to identify the negative impact of risk factors on peri-implant health, and to develop new therapeutic approaches for the treatment of peri-implant mucositis and peri-implantitis.

This article was published in DENTALZEITUNG 3/2017.