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Expert Panel Consensus Meeting on Monitoring, Diagnosis and Treatment of Peri-implant Disease

Report by: David Speechley

Dental implants have created new restorative possibilities, and treatment modalities only dreamt of two or three decades ago are now common place. Disease processes associated with dental implants makes the recognition and diagnosis of implant-related complications the responsibility of every clinician, whether actively engaged in placing or restoring implants or not.

Professor Nikos Donos

Professor Nikos Donos reminded us that peri-implant disease may be broken down into two distinct entities; the first, ‘mucositis’, an inflammatory response contained within the soft tissues (generally regarded as reversible), and the second, ‘peri-implantitis’, involving further tissue destruction and bone loss often proving less amenable to treatment.

Survival: proportion of implant still in place, even if it has no clinical value.

Success: focus on stability of marginal bone, but no single clear definition.

The lack of standardised and agreed definition of implant success produces conflicting and confusing results, making meta-analysis difficult if not impossible, thus limiting the power of high level systematic reviews. This is not only confusing for dental professionals, it leads to unrealistic patient expectations making implant therapy a potential minefield in terms of litigation and patient discontent.

The most common alleged negligence relates to failures in treatment planning, however failure to diagnose and treat peri-implant disease in a timely fashion appears to be highly represented in the litigation “league table” in third place. With increasing numbers of implants placed, the numbers of complications will inevitably rise. It is estimated that in Europe, based on figures from 2008, assuming a failure rate of 6.5% we should expect 67,000 implants to fail.

If we are to be able to measure and assess disease progression in our patients, then the recording of baseline data is imperative. In 2011 Lang and Berglundh proposed the time of prosthesis installation was the time to record baseline criteria, and should include:

  • A radiograph to determine alveolar bone levels.
  • After physiological remodelling peri-implant probing assessments should be performed.
  • When changes in clinical parameters indicate disease (BoP, increasing PPD) an x-ray should be taken.

Probing is a valid method of assessment as correlation exists between bone levels recorded and the radiographic probe penetration. (Quirynen et al 1991)

The diagnosis/assessment of peri-implantitis may be characterised by increased probing depths, BoP, suppuration and radiographic evaluation. Suppuration occurs more frequently in implants with than without “progressive” bone loss, particularly in smokers, and may be associated with episodes of active tissue destruction.

Restorative contours may make probing difficult, in addition to making oral hygiene measures ineffective. Implant design features such as platform switching may also make effective pocket depth probing difficult.

Bone loss around implants often occurs as a saucer defect. Which can be seen radiographically. Peri-implantitis associated with bone loss may occur in all positions of the jaws, with “end” positions not associated with extended risk. (Fransson et al 2009).

The pattern of bone varies between subjects, is non-linear in progression, and the rate of bone loss increases over time (Fransson et al 2010).

Since failing implants often demonstrate few if any patient perceptible signs or symptoms, it is the responsibility of the clinician to recognise disease, especially in the early and reversible stages. When clinical signs are overlooked for whatever reason by healthcare professionals, implant mobility may be the patient’s first perceived symptom, by which time all treatment options are gone, the implant has failed.

Risk Factors:
There is compelling evidence that poor oral hygiene, a history of periodontitis and cigarette smoking are major risk factors for the development of peri-implant disease. Limited evidence exists to link risk of peri-implant disease to alcohol consumption and diabetes, although the evidence linking diabetes and peri-implant disease would support the level of metabolic control of diabetes, which is itself an important factor in assessing risk. The evidence linking genetic traits and implant surfaces is limited and somewhat conflicting, although all the above may co-exist and their affects be synergistic.

Bacterial infection is the biggest risk factor for periodontal and peri-implant disease, colonisation occurs rapidly post placement, with a shift towards gram-negative proliferation and a thickening of biofilms in the progression of disease.

Patients with a past history of chronic periodontitis who have been stabilised have five-year survival figures not significantly lower than for populations never having been affected. However the longer term may be less positive, with significantly reduced success and survival at 10 years. Recent work suggests that patients with residual probing depths of 5 mm or more at the end of periodontal therapy run a higher risk of peri-implantitis and implant loss than patients with lower values. (Pjetursson et al 2012). Aggressive periodontitis is much rarer than chronic forms, but a significant risk factor for dental implant therapy, with significantly lower implant survival. (Mengel & Flores-de-Jacoby 2005)

Recommendations for clinical practice:

  • History of periodontitis and smoking lower survival rates and higher level of peri-implantitis. Must be identified and monitored.
  • Proper diagnosis of aggressive periodontal disease and close monitoring of those patients.
  • Peri-implant infections occur to a significant percentage of patients if supportive therapies are not provided, irrespective of previous periodontal health.
  • Complete treatment of periodontal disease and elimination of risk factors. Individual supportive therapy regimes for both natural teeth and implants should be devised and patient compliance are of paramount importance.
  • Dental implants do not surpass the longevity of successfully treated natural teeth (Holm-Pedersen et al 2007)

Professor Tord Berglundh

Professor Tord Berglundh  posed the question “Are peri-implant lesions different from periodontal lesions?” The evidence suggests that although the two-disease process appear clinically similar, there are significant and critical histopathological differences. (Berglundh, Zitman and Donati 2011).


Natural tooth showing inflammatory change within the gingival crevice.


Implant showing inflammatory change within the gingival crevice, noting the differences especially apically.

The mechanism for soft tissue attachment is fundamentally different around teeth compared with implants, the tooth having collagenous fibres attached to the cementum of the tooth, in a horizontal fashion, whilst the attachment in the case of the implant is by simple tissue repair process, forming a weaker (hemi-desmosomal) attachment.

Bacterial challenge may induce inflammatory change around teeth and implants, however not all cases of gingivitis or mucositis progress to become periodontitis or peri-implantitis. Early diagnosis renders treatment more likely to succeed, however peri-implantitis diagnosis and management is frequently complicated by elaborate superstructures or poorly designed crown work.

Once the soft tissue has broken down around an implant, then it is very vulnerable to peri-implantitis. It is therefore essential to make oral hygiene measures simple and effective. Calculus formation, suppuration and fistula formation are all easy to recognise, however early signs of disease may be far harder to recognise, and disease progression may be insipient.

In periodontitis the inflammatory process is contained and encapsulated within the pocket, progression being by ulceration of the pocket epithelium, however the base of the pocket in the case of peri-implantitis does not have an epithelial component, hence the disease progresses apically more rapidly. The absence of a periodontal ligament also means the inflammatory reaction is intimately associated with the implant surface and bone, with no protective element.

The prevalence of adult periodontitis has been estimated at over 47% in the USA (Eke et al 2012),  8.7% classed as mild, 30% as moderate, and 8.5% severe, although increasing age demonstrated a rise in disease severity. Figures for the incidence of peri-implantitis have been recorded in the literature ranging from as high as 56% to less than 1%, depending on definitions utilised. Looking at case definitions of peri-implantitis, variation in the diagnosis of disease between 27.8% to less than 1%  were recorded.  (Tomasi and Derks 2012).

Risk factors for peri-implantitis include host susceptibility to periodontitis, prosthetic design and implant surface-roughness-modification. Since host susceptibility cannot be changed, suitable prosthetic design is crucial, along with supportive therapy strategies, careful maintenance and rigorous monitoring.

Both human and animal studies have demonstrated disease progression around implants depending on the surface characteristics of the implant.

Spontaneous progression of experimentally-induced peri-implantitis is more pronounced than experimentally-induced periodontitis. There are significant histopathological differences existing between peri-implantitis and periodontitis lesions, with increased inflammatory cell infiltrate, proportions of polymorphonuclear cells and osteoclasts in cases of peri-implantitis.

Infection control can bring about resolution of both peri-implant mucositis and incipient peri-implantitis, however surface characteristics have a major influence, smooth surfaces being more amenable to successful treatment than roughened surfaces, with variation from manufacturer to manufacturer.

The goal of therapy must be to bring about resolution of peri-implant lesions and arrest further loss of supporting structures.

Pocket formation, loss of supporting tissue, with active destructive disease processes.

Following infection control the situation is now stable, with pocket closure and absence of bleeding on probing.

Dr Simon Wright

Dr Simon Wright presented the results of his study; the aim of this presentation was to establish current attitudes and protocols of UK implantologists towards the maintenance of dental implants and the treatment of peri-implant disease

Incidence and Re-occurrence
The results clearly demonstrate a wide diversity in maintenance protocols indicating that there is need for clear guidance and research. The perceived incidence in this study is consistent with a recent study where almost all respondents reported a prevalence less than 25%. 

Respondents recorded bacterial plaque and retained cement as the most common aetiological factor.  This presentation demonstrated the reversible nature of mucositis, however a significant number of respondents thought that peri-implantitis was not fully treatable.

Maintenance and Review
The best available evidence suggests that as a minimum base line, bleeding on probing, probing depths and radiographic bone levels should be recorded. This study found that there is a low level of recording of these key parameters.

The recall interval is very patient-specific, the majority of respondents reviewed the implant every six months.
This study also found that those in the ‘specialist’ and ‘most experienced’ groups used instruments that were effective in debridement – the Titanium hand scaler.  They were less concerned about damaging/scratching the implant surface, whereas the ‘less experienced’ group preferred the plastic scaler.  This is surprising as the literature states the ineffective nature of this instrument.

Treatment

  1. Supplemental Treatment:
    This study found universally across all the groups that oral hygiene instruction is fundamental in the management of peri-implant disease.  This finding is consistent with other similar studies in the literature.
    The majority of respondents considered oral rinses to be an essential adjunct in the treatment of mucositis and peri-implantitis.
  2. Systemic Antibiotics:
    This study found that 57% of the ‘most experienced’ and 67% of GDP’s placing implants prescribed systemic antibiotics for 2mm of bone loss, whereas only 40% of specialists used systemic antibiotics. 
    A wide selection of antibiotics were prescribed, and with the exception of the ‘most experienced’ for mucositis, who prescribed Metronidazole, the most commonly prescribed antibiotics, across all groups and all severities of disease, were Amoxycillin and Metronidazole in combination. 
  3. Non-surgical:
    Our study found that the majority of respondents agreed that mucositis may be treated without surgery, however 40% of ‘specialists’ and 30% of the ‘most experienced’ still felt it necessary to raise a flap.  This was almost always associated with effectively disinfecting and debriding the implant surface. 
  4. Surgical:
    The majority of respondents carried out surgery to disinfect the implant surface.  The more severe the lesion became the more respondents elected to carry out surgery.  Interestingly, although the literature suggests that regeneration of the tissue is also a key objective, relatively few grafted the implant (only 20% of the ‘specialists’, and 30% of the GDP’s grafted the even the most severe cases). 

The literature is consistent in that the prognosis of the peri-implant lesion is directly affected by early detection, and therefore prevention of disease and the long-term maintenance of our implants is fundamental. This makes the under-recording of key parameters a significant finding.

Sally Simpson

Sally Simpson reminded us that implant dentistry is a teamwork discipline, and summarised the role of dental hygienists and therapists. With the passage of time, hygienists and therapists are gaining patient acceptance and confidence, and have now become a vital part of long-term care and the maintenance team.

It is essential all that clinicians know and understand the scope of practice of the roles of the hygienist and therapist, and recognise any further post-registration qualifications which may extend possible duties further.

Currently the scope of practice for a dental hygienist includes dental examination, charting of teeth, periodontal charting and recording periodontal indexes, along with provisions of dental hygiene care, the delivery of care to improve and maintain periodontal health with manual and powered devices including ultrasonic scalers, air polishers for subgingival debridement using water/air/glycine based prophylaxis powder and topical application of antimicrobials as recommended by the referring practitioner in order to improve gingival condition.

Hygienists may also take impressions, take and develop radiographs, administer local anaesthetics, and the list goes on, all of which should prove invaluable to the busy implant dental clinic. Dental therapists may undertake additional duties, including removal of sutures under the direction of a dentist. To review the scope of practice go to http://www.gdc-uk.org/gdccalendar/consultations/pages/review-of-scope-of-practice.aspx

The role of the therapist fits into all aspects of the long-term care of patients, including pre-implant placement, during and post-surgical stages, long-term care and maintenance.

Dr Maria Retzepi

Dr Maria Retzepi reminded us that non-surgical treatment of periodontitis encompasses a variety of therapeutic modalities, which are performed without deliberately injuring the epithelial mucosa and which are characterised by an infection control strategy. It should be noted that peri-implant diseases are polymicrobial anaerobic infections and the disruption of the bacterial biofilm from the implant surface constitutes a basic element for the treatment of peri-implant diseases. Furthermore, it is advocated that the instruments used for surface decontamination should not make the surface more biofilm-retentive but they should aim to minimize de novo biofilm formation.

In vitro studies have reported that the use of metal instruments increases the titanium surface roughness. Titanium curettes, non-metal instruments, rubber cups and air abrasives seem to be the instruments of choice for the treatment of a smooth or rough implant surface, especially if the preservation of surface integrity is the primary goal.

Air abrasion, Er:YAG irradiation and photodynamic treatment have also demonstrated efficiency in removing plaque biofilms from both smooth and rough titanium surfaces. The presence of the suprastructure, the implant design and the implant surface characteristics may limit access to infected sites and as a result the non-surgical therapy may be rendered ineffective.

For the treatment of peri-mucositis, significant reduction in terms of bleeding on probing and probing depth values can be achieved following mechanical debridement, whereas no additional benefits from the adjunctive application of chlorhexidine gel or systemic antibiotic delivery have been shown.

In the presence of peri-implantitis, submucosal mechanical debridement alone may have limited efficacy especially in deeper lesions. Minor additional beneficial effects have been reported for Er:YAG therapy and for air-abrasive therapy with the application of amino acid glycine powder. The delivery of local antibiotics, i.e. doxycycline polymer device, minocycline microspheres and chlorhexidine gluconate chips, presents additional beneficial effects when used adjunctively to submucosal mechanical debridement.

A regular maintenance programme is needed for the long-term management of peri-implantitis lesions.

Professor Mariano Sanz

Professor Mariano Sanz commented that although the evidence is limited and somewhat confusing on the surgical management of peri-implantitis, people present on a regular basis with peri-implantitis-related problems and it is our responsibility to treat these people in the most appropriate manner, with many procedures based on those employed in the treatment of periodontitis.

The primary aim of initial therapy is the reduction of inflammatory response, reduction of risk factors and local non-surgical measures. Surgical periodontal therapy should only be initiated following careful and intense initial therapy which must include debridement, and decontamination of the implant surface, along with local or systemic antibiotics.

The consensus is that if non-surgical mechanical therapy and adjunct antimicrobials do not resolve the lesion, then access flap surgery is recommended.

Access flap surgery, removal of granulation tissue and implant surface decontamination may decrease plaque indexes, BOP, suppuration and probing depths. Such measures may cause further bone loss to be arrested in up to 58% of implant sites over 5 years (Renvert S., Polyzois I, Claffey N).  The evidence suggested that reconstruction using bone and other grafting materials may be beneficial in producing defect infill, however neither membranes nor adjunct use of lasers has shown to be beneficial. The use of membranes without grafting materials also appears to be of no benefit.

Access Flap and Debridement

One week post-operative

 

One year post surgery

Once roughened surfaces have become exposed, therefore contaminated, it is likely that smoothing the surface may reduce plaque retention, and in combination with resective surgery aid the resolution of peri-implantitis (Romeo et al 2007). Care must be taken to limit heat production on the smoothing of the titanium surface; also attempts should be made to limit the scatter of debris particles. The degree of disease resolution would seem dependant on the initial bone loss around the implants. (Serino and Turri 2011).

The evidence relating to the importance of keratinised mucosa is conflicting, however most researchers conclude that a band of keratinised mucosa will help prevent the penetration of microbes, and is especially important where there may be an attached frenum liable to cause mucosal pulling. 

The incidence of peri-implantitis is greater around cement restorations than screw-retained restorations. Removal of any excess cement at the time of placement may be difficult and hampered by complicated superstructure design, or deep implant placement. When treating peri-implant lesions it is always beneficial to remove the superstructure to allow optimal access to what is a circumferential lesion.

Approximately half the cases of peri-implantitis when treated surgically do not have successful outcomes. Smoking and early onset of disease are risk factors, whilst bone recontouring and antibiotics during the surgical stages, along with excellent oral hygiene regimes seem to be associated with increased rates of success. (Charalampakis G. et al 2011).

The distal SLA surface Straumann implant may be seen to display the typical saucer shaped defect associated with peri-implantitis, with marked bone loss.

Following flap surgery, debridement with adjunct use of YAS laser, and bone grafting, regeneration occurred and was stable at one year post surgery.

The use of antibiotics seems to be generally agreed to be beneficial in these cases, but since almost no papers on the surgical treatment of peri-implantitis have been carried out without the use of antibiotics, it is impossible to quantify their effect.

Conclusions

  1. Early diagnosis and control of infection are key factors influencing the outcome of peri-implantitis
  2. Thorough debridement of the area, and the implant surface in particular, is a pre-requisite to the successful management of peri-implantitis
  3. Modification of the surface may be beneficial to make it non-plaque retentive
  4. Plaque control by the patient is crucial if successful outcomes are to be achieved
  5. There is a possibility that regeneration may occur
  6. It is necessary to understand the patho-biology of the lesion and to implement appropriate focused therapies

 

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