Peri-Implant Diseases

Peri-implant diseases are inflammatory conditions that affect the soft and hard supporting tissues around implant fixtures.

Peri-implant mucositis usually responds to oral hygiene instructions, scaling and prophylaxis, but peri-implantitis, which involves bone resorption, has less predictable treatment outcomes following non-surgical management. Adjunctive treatment for decontaminating sites may include the use of antimicrobials and resistant cases may sometimes be managed with a surgical approach.

As dental implant-retained prostheses become more popular the prevalence of peri-implant complications will also increase. Dental practitioners and care professionals should appreciate their potential roles in the management of these conditions.

Dental implants, like natural teeth, are susceptible to inflammatory diseases that are predominantly driven by

the accumulation of dental plaque. These conditions are categorized into those that are limited to the peri-implant soft tissues (peri-implant mucositis) and those that also affect the alveolar bone support (periimplantitis).

Peri-implant mucositis: 

Peri-implant mucositis is a reversible, inflammatory lesion affecting the marginal soft tissues that surround

osseointegrated dental implants but does not involve the resorption of the supporting bone. This condition

corresponds to gingivitis around natural teeth and presents as redness and swelling of the soft tissues. Bleeding on probing is the clinical sign that confirms diagnosis. As with chronic gingivitis,

a necrotizing ulcerative condition may develop when risk factors such as smoking are present.

Peri-implantitis:

Peri-implantitis is an inflammatory lesion that affects the supporting bone as well as the surrounding

soft tissues of a functioning implant.4-6 This condition broadly corresponds to periodontitis around the natural teeth. In addition to bleeding on probing, affected sites may exude pus and are

always accompanied by marginal bone loss. To distinguish pathological bone resorption from physiological remodelling of the alveolar crest the loss of bone height should involve ≥ 3 threads ofthe implant fixture (1.8 mm) following the first year in function

Identifying patients at risk:

For patients with periodontal diseases it is crucial that associated risk factors are identified, modified or

eliminated if the benefit of treatment is to be maximized. The same strategy applies to patients with peri-implant diseases and, although it might be anticipated that risk factors are addressed adequately before the

placement of implants, this may not always be the case. Patients who are unable to achieve a good standard of plaque control are at increased risk of peri-implant disease with an odds ratio of 2.9 for peri-implant

mucositis and 14.3 for peri-implantitis, and the association between plaque and disease is ‘dose-dependent’. The ability of patients to clean effectively around implant fixtures, however, may not be assumed

from their ability to achieve a high standard of plaque control around the natural dentition. Therefore careful instruction in plaque control measures around implants in the immediate post-placement period is

essential.

There is also an increased prevalence of peri-implantitis in patients with a history of periodontitis

when compared to non-periodontitis patients, although the extent to which this might impact on overall implant survival in the long-term is unclear. A history of periodontitis does not preclude the placement of implants, but the disease should be stabilized with high level maintenance to minimize the opportunity for periodontal pathogens from periodontally-active sites to colonize peri-implant tissues. It is important to

appreciate, however, that the risk for peri-implant infection is still present even when implants are placed in edentulous patients; an implant will still provide a favourable ecological niche for colonization

by commensal oral bacteria  Indeed, a number of bacterial species such as Peptostreptococcus stomatitis, Mycoplasma salivarium and Pseudoramibacter alactolyticus, that are not linked with healthy implant sites or periodontal disease, have been identified at sites of periimplantitis

Smoking is a known risk factor for periodontal diseases and there is a substantial evidence base of long-term

studies that implicate the habit as a risk factor for peri-mucositis, peri-implantitis and total implant failure.These associations have been substantiated unequivocally by systematic review and meta-analysis20 and, whilst there are few data to suggest otherwise, it must be assumed that cigarette smoking will impact

negatively on attempts both to prevent and manage peri-implant disease in the longterm.

Diagnosis of peri-implant

disease:

• Clinical assessment

Visual assessment alone will reveal an inflamed gingival cuff, although scar reactions in the soft tissues, for

example after bone grafting and tissue manipulation, may mask inflammatory reactions of the mucosa. Probing is essential and may be undertaken circumferentially or at four sites around an implant fixture. A

plastic (TPS or WHO 621) probe has greater flexibility than a metal counterpart, may cause less contamination and damage to the implant surface, and is potentially more accurate as it can adapt more readily to the abutment-suprastructure junction. A light probing force of around0.15–0.2N is recommended; the absence of gingival connective tissue fibres attached to the implant surface means that there

is minimal resistance to probing. In the presence of peri-implantitis there is an extensive, unencapsulated neutrophil infiltrate and the periodontal probe is likely to penetrate the entire depth of the

Bleeding following gentle probing is the characteristic sign for peri-implant mucositis and suppuration

following probing is indicative of periimplantitis. Probing depth may be influenced by the implant system and the suprastructure used: a gingival cuff with a probing depth of 5 mm but with no bleeding on probing may be consistent with health. If initial probing depths are recorded about one month after implant placement, then future measurements, recorded for example on an annual basis, can be compared to the baseline record.

Any mobility within a year of placing an implant and/or its suprastructure is more likely to be a sign of lack of

osseointegration, fracture of the implant or mobility and fracture of the suprastructure

rather than an early sign of peri-implantitis. The only reliable method for assessing mobility (other than for a single tooth implant) is to dismantle the suprastructure so that the implant fixture(s) can be assessed independently. Late mobility of a successfully integrated implant, however, may be an additional sign of advanced or progressing peri-implantitis.

• Radiographic assessment

High quality, long cone periapical radiographs are the films of choice for assessing implant fixtures. The

ideal exposure will reveal the external configuration of the implant and the thread profile is likely to be visible unless there is a vertical discrepancy of ≥ 15° from the perpendicular between the beam and the

film surface.23 The normal bone density around osseointegrated fixtures was described originally as having perifixtural trabeculations radiating from the implant surface24 and radiographic evidence of

a bone trough extending apically to the first thread may be consistent with health being a manifestation of bone remodelling and re-establishment of the biologic width of peri-implant tissues. A radiographic

observation of bone resorption mesial and distal to the implant of ≥ 3 threads will confirm a diagnosis of peri-implantitis.7 If a ‘baseline’ radiograph is taken at the time of placement of the suprastructure, then

further films can be exposed at 6 and 12 months at the time of greatest remodelling of bone and when complications are most prevalent, and then at 2-3 year intervals thereafter. More frequent exposures on

an annual basis are indicated when there are persistent clinical signs of peri-implant disease and when there is an increased risk of complications, such as when implants are placed in a patient with a history of

periodontal disease. It must, however always be remembered that this type of radiography is purely two dimensional and therefore gives no indication as to any potential buccal bone loss that may have occurred.

Treatment of peri-implant

disease:

Comprehensive reviews of the treatment of peri-implant diseases have made important conclusions:

•  That mechanical, non-surgical therapy

may be effective in the treatment of periimplant mucositis and that the adjunctive use of antimicrobial mouthrinses may enhance the clinical outcomes;

•  That non-surgical therapy for periimplantitis

is not a predictable treatment even with adjunctive chlorhexidine mouthrinse. Adjunctive local or systemic

antibiotics , however, may be effective in reducing probing depths and resolving bleeding on probing;

•  Adjunctive Listerine mouthrinse can

reduce dental plaque and marginal bleeding and may provide some benefit in the management of peri-implant mucositis. The relatively superficial nature of peri-implant mucositis is the most likely reason that this condition responds favourably to intensive oral hygiene instruction, scaling, prophylaxis and mouthrinsing with chlorhexidine. As lesions develop, however, their local anatomy, the complex morphology of

the exposed fixture and the profile of suprastructure-implant fixture design will inevitably compromise the ability of the clinician to debride the site effectively and the ability of the patient to maintain the area free from dental biofilm .

Mechanical, non-surgical treatment (using specifically designed titanium curettes and the Vector ultrasonic system with tips designed for treatment around dental implants) is effective in reducing dental plaque deposits and soft tissue bleeding,

although the effects on probing depths and the pathogenic subgingival microflora are limited. Titanium curettes are less likely than conventional instruments to alter or damage the implant surface, but their

restricted ability to ‘work’ horizontally and circumferentially between the threads on the part of a fixture exposed through periimplantitis will limit effectiveness. Similarly,

plastic manual instruments which may be useful for scaling in the supragingival environment may be less effective when attempting to remove deposits from between the threads .

Because of the problem with access to the affected part of the fixture, the Implantic Debrider™ has been recently introduced . This rotatory instrument cleans down to the titaniumsurface between the threads of the exposed fixture at 400 rpm with copious water cooling, but the suprastructure must be dismantled to allow access .

Er-YAG Lasers have also been used for decontaminating peri-implantitis affected implant surfaces, but again,access has proven challenging and the outcome data from relatively small studies

have yet to demonstrate significant benefit when compared to conventional

mechanical therapy.

 Ultrasonic instruments with plastic tips (SoftTip™, Dentsply PA, USA) are also conceptually attractive for use on implant surfaces and, although their efficacy in removing deposits from affected surfaces has yet

to be determined, there is evidence to suggest that they inflict far less damage on

the titanium surface than do conventional metal ultrasonic instruments .

The objective of treatment of peri-implantitis is to reduce or eliminate the bacterial load and so allow healing to occur.

When there is evidence of bone cratering and thread exposure, and when mechanical therapy alone may be effective, then adjunctive antimicrobial therapy may be an option. Minocycline microspheres (Arestin®,

Orapharma, Johnson and Johnson) adhere to the walls of peri-implant pockets and are

retained in high enough concentrations to be effective against biofilm. They appear

to be a valuable adjunct to mechanical debridement in patients with periimplantitis

When peri-implantitis sites appear to be unresponsive to non-surgical management, pockets continue to bleed or suppurate and there is bone loss of ≥2mm (involving 3 or more threads of the

implant fixture), then referral to a specialist may be indicated for consideration of a surgical approach to achieve better access for decontamination, and perhaps consider regenerative procedures in the longer term.

Peri-implant supportive care:

It is crucial that any patient with an implant-retained prosthesis is enrolled into an individually-tailored programme of supportive care, with the emphasis being on a preventive approach to potential

peri-implant problems and early diagnosis of developing peri-implant disease.

Risk assessment should be ongoing, for example to establish smoking status (has an ex-smoker relapsed?) and the overall maintenance of patients who have a history of periodontal disease. The design of suprastructures should facilitate oral hygiene practices and the use of soft bristle toothbrushes (manual or powered) should be reviewed. Single-tufted, interspace brushes, and interdental tape and brushes with plastic-coated wire hubs are essential for cleaning around fixtures and beneath the suprastructure. Scaling and prophylaxis should be undertaken with plastic manual or ultrasonic instruments with a view

to minimizing the deposit of calculus, disrupting and removing biofilm and ensuring an environment that is consistent with peri-implant health.

Conclusion:

Peri-implant diseases are likely to become more prevalent as the popularity of implant-retained prostheses

continues to increase. Prevention is the optimal strategy but early identification of peri-implant complications is essential if inflammation in the supporting soft tissues is to be resolved. Peri-implantitis, however,

is a more challenging condition and treatment success may be unpredictable.

Nevertheless, a conventional, non-surgical approach should be attempted.