The Key Points of Maintenance Therapy for Dental Implants: A Literature Review

The use of dental implants has revolutionized dental treatment and has proven to be a successful and predictable solution for treatment of partial or full edentulism.¹ The placement of dental implants in patients with partial edentulism represents an efficacious therapy for replacing natural teeth.² The commonly accepted criteria for the assessment of implant success, proposed by Albretksson,³ included identifying clinical and radiograph evidence of the successful osseointegration and survival of the implant. Implant success has been described by using biologic factors (presence of inflamed soft tissues surrounding dental implants and radiographic changes in the crestal bone levels) and mechanical factors (stability of the implant fixture and implant supported restoration, etc).^3-9 A compiled list of the updated implant success criteria currently used is summarized in Table 1.

Despite the high survival and success rates of dental implants (survival rates greater than 95% at 5-year follow-up¹⁰ to even 100%, and overall treatment success rate of 86.7%¹¹), it is clear that osseointegrated implants are susceptible to diseases that may eventually lead to dental implant loss.¹² Most implant failures are initiated by incipient stages of inflammatory processes, which lead to peri-mucositis and peri-implantitis.^13-17 However, some authors reveal a critical role played by the mechanical overload in the etiology of implant failure.^13,18,19 Several factors provide a risk for peri-implant complications, such as biologic issues (colonization of the peri-implant sulcus with specific pathogenic microorganisms), systemic conditions (uncontrolled or poorly controlled diabetes mellitus, osteoporosis, etc), mechanical problems (residual cement, bacterial microleakage between the implant abutment interface, implant surface characteristics, type of the prosthetic suprastructure, etc), and lifestyle habits (smoking).^13,20

One of the main reasons implant complications are gaining more attention is that more dental implants are placed every year. Initially, oral surgeons and periodontists inserted most dental implants; however, more general dentists are performing the procedures. As the popularity of the dental implants grows, so do the number of products available on the market. Some products are supported by short-term studies of the clinical success. Market estimates showed more than 900,000 dental implant procedures were performed annually in Europe,²¹ and more than 3 million people in the United States have implants and this number is growing by 500,000 a year according to the American Academy of Implant Dentistry.²²

The etiology of implant failure is complex, and future studies are required to reach an expert consensus. Some authors indicate complications can occur in early stages. Most agree that problems can be caused by osteonecrosis during the preparation of the osteotomy, improper asepsis during the surgical procedure, and compromised primary stability by immediate loading with implant supported provisional restorations. Peri-implantitis occurs only when the implant has been restored and in function with the prosthetic component.¹³ Only a small number of studies are available addressing the risk indicators/factors in peri-implant mucositis.

Some patients are unaware that implants require a thorough oral hygiene protocol similar to normal teeth. Poor oral hygiene is a significant risk factor for the development of peri-implant mucositis, which can be reversible if treated in the early stages.²³ In clinical situations in which peri-implant mucositis has not been diagnosed and treated appropriately, the inflammatory process can advance and lead to the loss in crestal bone levels, identified as peri-implantitis.^21,24,25 The literature reports peri-implantitis affects 7.8% to 43.3% of all dental implants.²⁶

Several clinical studies have revealed the importance of supportive recare sessions in maintaining the periodontal health.^21,27-36 In a position paper published by the American Academy of Periodontology,^21,37 supportive periodontal therapy (SPT) after placement of dental implants is essential. The procedures for maintenance of implants are modified from SPT. The examination of the implant health include the probing depths, bleeding on probing, prosthesis/abutment components, implant stability, occlusion, and signs of disease activity (eg, pain, suppuration).³⁷ Several factors are evaluated at the maintenance visits and presented in Table 2.

In 2000, Lang designed a protocol of therapeutic measures to arrest the development of peri-implant lesions. Called the cumulative interceptive supportive therapy (CIST), the process is cumulative and includes four steps (A through D) that should be followed as a sequence of therapeutic procedures with increasing antibacterial potential depending on the severity of the lesion. First, sequences are mechanical, antiseptic, and antibiotic to control any ongoing infection. Following this, peri-implant bony lesions can be corrected by regenerative or respective surgical procedures.²⁴ Several cohort studies consider CIST as a viable option to manage and control various implant conditions.^21,38-40

Numerous studies have demonstrated the efficiency of SPT and have shown recurrent periodontitis can be prevented or limited by optimal plaque control regimen or through periodic SPT. Patients who maintain regular recare visits have less attachment loss and lose fewer teeth than patients who do not respect the maintenance protocol.³⁷ The evidence regarding the value of maintenance protocol regarding implants is sparse compared with the one for teeth. Many of the cited references focus on surgical technique for placing implants, and most corporate investments are financing development of new implant surfaces rather than new efficient maintenance strategies. According to recent published studies, the cost of the maintenance for the implants is almost 5 times more expensive compared to the maintenance of the teeth.⁴¹ Given the high prevalence of the disease and costs associated with the implant therapy and subsequent prosthetic restoration, a good maintenance protocol should be established and followed. The aim of the study is to review and identify the significance of maintenance protocols.

The current review provides compiled information of the published implant maintenance protocols available. The comprehensive data is a good start in identifying and assessing the key parameters that long-term clinical trials should consider. Clinical trials are the most appropriate study designs to evaluate the best practices in maintaining successful long-term outcomes for dental implants.

The maintenance appointment should be similar to the one of supportive appointment with the time frame of an hour and should be divided in four phases.^24,42 It should consist of examination, reevaluation, and diagnosis; motivation and reinforcements of the oral hygiene instructions; debridement (prophylaxis and instrumentation); treatment of infected sites; and polishing and determining recall interval.

The recall hour generally consists of 10 to 15 minutes of diagnostic procedures (examination, reevaluation, and diagnosis) followed by 30 to 40 minutes of motivation, reinstruction, and instrumentation, with the instrumentation concentrated on the sites diagnosed with persistent inflammation. The recall hour is normally concluded with polishing of the entire dentition, and another assessment of the situation, including the determination for the frequency of future visits.⁴³

In the first 10 to 15 minutes, an update on general health issues is appropriate. All extraoral and intraoral soft tissues should be examined to detect any abnormalities and for screening for oral cancer. The information gathered at each maintenance visit for patients with implants should include evaluation of the oral hygiene techniques and the level of plaque control; probing depth, mobility, and bleeding on probing; assessment of the development of any mucogingival deformities; monitoring the occlusion; accurate baseline and follow-up radiographs examination; and early intervention for patients with peri-implant disease.⁴⁴

The amount of time available for this part is fairly short, so it should be well organized and done in the same protocol every time to avoid any mistakes.

Motivation, reinstruction, and instrumentation take the most time in the maintenance visit. However, it is a crucial part of a visit and its importance should not be overlooked. Good plaque control habits and regular visits should be stressed, and reinforcing the value of appropriate plaque control methods should be showed and explained again.⁴³ This should include brushing technique (either manual or electric/sonic), interproximal cleaning (flossing, interproximal brushes), and optionally water irrigation.⁴⁵

The other part of the visit should be focused on infected sites and debridement according to the current standards, and the recall schedule should be modified according to the patient’s needs. A dental hygienist can perform the debridement. When the disease is more severe and bone loss is evident, it should be referred to a specialist.⁴³

In the first year after the implant has been placed, changes in the crestal bone levels occur due to bone remodeling. To monitor any clinical changes that might occur, the patient should be seen every 4 months during the first year after the implant has been restored and problems should be identified by the presence of probing depth, bleeding on probing, suppuration, etc.⁴³

The most common signs for peri-implant mucositis are color changes and bleeding on probing.⁴⁴ Nonsurgical treatment usually includes debridement with curettes or via air abrasion; these can be with antibiotic or anti-infective therapy.⁴⁶ For the latter, chlorhexidine rinses or deposits or erbium:yttrium-aluminum-garnet (Er: YAG) laser application are used.^47-49 Sparse and controversial literature is available regarding the role of instrumentation on implant surfaces.^37,50-53 However, no clinical data support the hypothesized relationship between implant maintenance technique and implant failure.³⁷ Different materials for scaling instruments are commercially available. It has been reported that standard steel instruments (curettes and ultrasonic tips) scratch the titanium surface of the implant, while plastic instruments produce no significant changes.⁵⁰ Another option is using golden-tipped curettes. Because gold is softer than titanium, it is less likely to scratch the titanium surface of the implants.³⁷

Some in the dental community do not agree on the key features that should make up the maintenance visit; the recommended implant maintenance protocols are highlighted in Table 2. However, most authors have a few parameters in common, which are: plaque evaluation, bleeding assessment, measuring of probing depth, bleeding of probing, and radiographic interpretation. Different authors use various systems for the evaluation, which brings confusion when comparing the results.

A decision tree (Figure 1) is proposed in terms of assessing the implants at the recare visits and the step-by-step process that should follow according to the clinical, radiographic, and patient factors.

The evidence regarding the value of maintenance protocol regarding implants is sparse compared with the one for teeth. Many cited references focus on surgical technique for placing implants, and most corporate investments are financing new implant surfaces rather than new efficient maintenance strategies. Numerous protocols are commonly used, and most evaluate the same parameters but with different systems. For instance for plaque assessment, some authors use a modified plaque index and some full mouth plaque score. Many criteria are available that some count as important factors for evaluation of the implant health, such as subjective symptoms, and mobility. The value of maintenance of the implants should be emphasized and patients should be encouraged to return regularly to the office after the implant has been placed and restored.

Miha Pirc, DMD
General Dentist
Vocational Training Program
University Hospital Ljubljana Dental Hospital
Ljubljana, Slovenia

Irina F. Dragan, DDS, MS
Assistant Professor
Department of Periodontology
Tufts University School of Dental Medicine
Boston, MA