Interventions for replacing missing teeth: treatment of perimplantitis

Background One of the key factors for the long-term success of oral implants is the maintenance of healthy tissues around them. Bacterial plaque accumulation induces inflammatory changes in the soft tissues surrounding oral implants and it may lead to their progressive destruction (perimplantitis) and ultimately to implant failure. Different treatment strategies for perimplantitis have been suggested, however it is unclear which are the most effective. Objectives To identify the most effective interventions for treating perimplantitis around osseointegrated dental implants. Search strategy We searched the Cochrane Oral Health Group's Trials Register, CENTRAL, MEDLINE and EMBASE. Handsearching included several dental journals. We checked the bibliographies of the identified randomised controlled trials (RCTs) and relevant review articles for studies outside the handsearched journals. We wrote to authors of all identified RCTs, to more than 55 dental implant manufacturers and an Internet discussion group to find unpublished or ongoing RCTs. No language restrictions were applied. The last electronic search was conducted on 7th January 2010. Selection criteria All RCTs comparing agents or interventions for treating perimplantitis around dental implants. Data collection and analysis Screening of eligible studies, assessment of the methodological quality of the trials and data extraction were conducted in duplicate and independently by two review authors. We contacted the authors for missing information. Results were expressed as random-effects models using mean differences for continuous outcomes and risk ratios for dichotomous outcomes with 95% confidence intervals (CI). Heterogeneity was to be investigated including both clinical and methodological factors. Main results Twelve eligible trials were identified, but five were excluded. The following procedures were tested: (1) use of local antibiotics versus ultrasonic debridement; (2) benefits of adjunctive local antibiotics to debridement; (3) different techniques of subgingival debridement; (4) laser versus manual debridement and chlorhexidine irrigation/gel; (5) systemic antibiotics plus resective surgery plus two different local antibiotics with and without implant surface smoothening; and (6) nanocrystalline hydroxyapatite versus Bio-Oss and resorbable barriers. Follow-up ranged from 3 months to 4 years. The only statistically significant differences were observed in two trials judged to be at high risk of bias. After 4 months, adjunctive local antibiotics to manual debridement in patients who lost at least 50% of the bone around implants showed improved mean probing attachment levels (PAL) of 0.61 mm and reduced probing pockets depths (PPD) of 0.59 mm. After 4 years, patients with perimplant infrabony defects > 3 mm treated with Bio-Oss and resorbable barriers gained 1.4 mm more PAL and PPD than patients treated with a nanocrystalline hydroxyapatite. Author's conclusions There is very little reliable evidence suggesting which could be the most effective interventions for treating perimplantitis. This is not to say that currently used interventions are not effective. The use of local antibiotics in addition to manual subgingival debridement was associated with a 0.6 mm additional improvement for PAL and PPD over a 4-month period in patients affected by severe forms of perimplantitis. After 4 years, improved PAL and PPD of about 1.4 mm were obtained when using Bio-Oss with resorbable barriers compared to a nanocrystalline hydroxyapatite in perimplant infrabony defects. In four trials, the control therapy which basically consisted of a simple subgingival mechanical debridement seemed to be sufficient to achieve similar results to the more complex and expensive therapies. Follow-up longer than 1 year suggested recurrence of perimplantitis up to 100% of the treated cases for some of the tested interventions. Sample sizes were very small and follow-up too short, therefore these findings have to be considered with great caution. Larger well-designed RCTs with follow-up longer than 1 year are needed.