Long Term Comparison of Ultrasonic and Hand Instrumentation in the Maintenance of Peri-implant Tissues: A Randomized Clinical Trial

Nowadays, dental implants are a very attractive and affordable treatment option for patients. According to the American Society of Implant Dentistry the dental implant market in the U.S is projected to reach $1.3 billion by 20101. Despite the high success rates of dental implants, it is clear that osseointegrated implants are susceptible to diseases. The prevalence of dental implant complications are rising as the number of individuals that are receiving implant treatment is also increasing. One of these peri-implant complications is an inflammatory condition known as peri-implant mucositis that occurs in 64.6% to 80% of the implant population.

The lack of preventive maintenance therapy in subjects with peri-implant mucositis is associated with a high incidence of peri-implantitis, which eventually may lead to implant loss. One important method in the prevention of peri-implant mucositis is the reduction in plaque accumulation, through individual oral hygiene procedures and regular peri-implant professional maintenance. It is highly important that patients be educated about the importance of developing good oral hygiene habits and to attend regular periodontal maintenance appointments. The clinicians have to recognize the significance of monitoring and maintaining peri-implant health.

Unfortunately, it is unclear which of the different maintenance regimens and treatments strategies for peri-implant mucositis and peri-implantitis are more effective. There is lack of information about which peri-implant maintenance protocol offers the best outcome in terms of reduction of inflammation and improved patient comfort. According to Grusovin et al, "there is only low quality evidence for which are the most effective interventions for maintaining or recovering health of peri-implant soft tissues and there is no reliable evidence as to which regimens are most effective for long term maintenance". Moreover, current approaches to implant maintenance are somewhat haphazard and not standardized.

It is assumed that what is appropriate for teeth is also beneficial for implants; as stated by Persson et al, 2010 "therapies proposed for the management of peri-implant diseases are currently based on the evidence available from the treatment of periodontitis". Two conventionally used methods of biofilm and calculus removal from teeth in North America are hand instruments (curettes and scalers) and ultrasonics. In teeth these two modalities of treatment have been studied extensively; conversely, there are fewer studies on dental implants. Renvert et al, 2008 concluded that mechanical non-surgical treatment might be effective to treat peri-implant mucositis but not peri-implantitis; however, the data supporting this literature review was scarce. The same research group compared ultrasonic instrumentation with specific-implant tips to titanium curettes in the treatment of peri-implantitis founding no group differences in the treatment outcomes with improvements in plaque and bleeding scores but no effects on probing depths. In addition, both methods failed to eliminate or reduce bacterial counts and no group differences were found in the ability to reduce the microbiota in a six months period.

One of the main concerns for dental implants is that metal scalers and ultrasonics generate a roughened surface on the implant, which in turn facilitates plaque accumulation and therefore makes maintenance of plaque free surfaces more difficult. It was observed in a recent study that special coated scalers and ultrasonic tips have been shown in vitro to be compatible with implant surfaces, however this has not been confirmed in vivo. The previous finding is in agreement with a current study, which demonstrated that the roughness values of the titanium surface of implants treated with piezoelectric ultrasonic scalers with a newly developed metallic tip and plastic hand curettes, are equal to the surface's roughness of untreated implants. Mann et al, 2012 showed in an in vitro study that plastic-coated scalers cause minimal damage to the implant surface but leave plastic deposits behind on the implant surface, suggesting further research is needed to evaluate the use of such plastic tips in the debridement of implants.

An additional factor, in evaluating the efficacy of different instrumentation in peri-implant maintenance, which needs to be taken into consideration, is patient perception. There is currently no data evaluating patient perception of comfort in regards to hand vs. ultrasonic instrumentation. This information is very important because should both methods of debridement be considered of equal efficacy, patient preference may play a role in the practitioner's selection of instrumentation. Knowing that patient comfort will increase the patient's compliance to the maintenance therapy, further evaluation of this factor is necessary.