A Novel Treatment Decision Tree and Literature Review of Retrograde Peri‐Implantitis

Background: Although retrograde peri‐implantitis (RPI) is not a common sequela of dental implant surgery, its prevalence has been reported in the literature to be 0.26%. Incidence of RPI is reported to increase to 7.8% when teeth adjacent to the implant site have a previous history of root canal therapy, and it is correlated with distance between implant and adjacent tooth and/or with time from endodontic treatment of adjacent tooth to implant placement. Minimum 2 mm space between implant and adjacent tooth is needed to decrease incidence of apical RPI, with minimum 4 weeks between completion of endodontic treatment and actual implant placement. The purpose of this study is to compile all available treatment modalities and to provide a decision tree as a general guide for clinicians to aid in diagnosis and treatment of RPI. Methods: Literature search was performed for articles published in English on the topic of RPI. Articles selected were case reports with study populations ranging from 1 to 32 patients. Any case report or clinical trial that attempted to treat or rescue an implant diagnosed with RPI was included. Results: Predominant diagnostic presentation of a lesion was presence of sinus tract at buccal or facial abscess of apical portion of implant, and subsequent periapical radiographs taken demonstrated a radiolucent lesion. On the basis of case reports analyzed, RPI was diagnosed between 1 week and 4 years after implant placement. Twelve of 20 studies reported that RPI lesions were diagnosed within 6 months after implant placement. A step‐by‐step decision tree is provided to allow clinicians to triage and properly manage cases of RPI on the basis of recommendations and successful treatments provided in analyzed case reports. It is divided between symptomatic and asymptomatic implants and adjacent teeth with vital and necrotic pulps. Conclusions: Most common etiology of apical RPI is endodontic infection from neighboring teeth, which was diagnosed within 6 months after implant placement. Most common findings, radiographically and clinically, are lesions around implant apex and sinus tract. A small number of implants did not improve with treatment. Decision tree provides a path to diagnose and treat lesions to facilitate their management. Further studies are needed to focus on histologic data around periapical microbiota to establish specific etiology and differential diagnoses compared with marginal peri‐implantitis and other implant‐related conditions.     

Increased Levels of Dissolved Titanium Are Associated With Peri‐Implantitis – A Cross‐Sectional Study

Background: Peri‐implantitis represents a disruption of the biocompatible interface between the titanium dioxide layer of the implant surface and the peri‐implant tissues. Increasing preclinical data suggest that peri‐implantitis microbiota not only triggers an inflammatory immune response but also causes electrochemical alterations of the titanium surfaces, i.e., corrosion, that aggravate this inflammatory response. Thus, it was hypothesized that there is an association between dissolution of titanium from dental implants, which suggests corrosion, and peri‐implantitis in humans. The objective of this study is to compare levels of dissolved titanium in submucosal plaque collected from healthy implants and implants with peri‐implantitis. Methods: Submucosal plaque from 20 implants with peri‐implantitis and 20 healthy implants was collected with sterile curets from 30 participants. Levels of titanium were quantified using inductively coupled plasma mass spectrometry and normalized for mass of bacterial DNA per sample to exclude confounding by varying amounts of plaque per site. Statistical analysis was performed using generalized estimated equations to adjust for clustering of implants per participant. Results: Implants with peri‐implantitis harbored significantly higher mean levels of titanium (0.85 ± 2.47) versus healthy implants (0.07 ± 0.19) after adjusting for amount of plaque collected per site (P = 0.033). Conclusions: Greater levels of dissolved titanium were detected in submucosal plaque around implants with peri‐implantitis compared with healthy implants, indicating an association between titanium dissolution and peri‐implantitis. Factors triggering titanium dissolution, as well as the role of titanium corrosion in the peri‐implant inflammatory process, warrant further investigation.     

Treatment Outcome in Patients With Peri‐Implantitis in a Periodontal Clinic: A Retrospective Study

Background: The number of placed implants has grown during the past decade, and the prevalence of peri‐implantitis has increased. The purpose of the present study is to investigate the treatment outcome of peri‐implantitis and to identify factors influencing the treatment success rate. Methods: The study was conducted as a retrospective longitudinal study on a referral population. The material included 382 implants with peri‐implantitis in 150 patients. Peri‐implantitis was defined as presence of pocket depths ≥5 mm, bleeding at probing and/or suppuration, and the presence of implant radiographic bone loss ≥3 mm or bone loss comprising at least three threads of the implant. Variance analyses, χ² analyses, and logistic regression analysis were used for data analyses. Results: The mean age of the participants at baseline was found to be 64 years (range: 22 to 87 years). The mean ± SD follow‐up time was 26 ± 20 months, and the mean time between implant installation and baseline was 6.4 years (range: 1 to 20 years). Periodontal flap surgery with osteoplasty was the most common type of therapy (47%), and regenerative surgery procedures with bone substitute materials were chosen in 20% of the cases. The mean success rate at patient level was 69%. The results of the logistic regression analyses showed that the success rate was significantly lower for individuals with the diagnosis of severe periodontitis, severe marginal bone loss around the implants, poor oral hygiene, and low compliance. Conclusion: The effectiveness of the peri‐implantitis therapy was impaired by severe periodontitis, severe marginal bone loss around the implants, poor oral hygiene, and low compliance.     

Preventing and Treating Peri‐Implantitis: A Cost‐Effectiveness Analysis

Background: A large number of treatments for peri‐implantitis are available, but their cost‐effectiveness remains uncertain. This study evaluates the cost‐effectiveness of preventing and treating peri‐implantitis. Methods: A Markov model was constructed that followed each implant over 20 years. Supportive implant therapy (SIT) for managing peri‐implant mucositis and preventing development of peri‐implantitis was either provided or not. Risk of peri‐implantitis was assumed to be affected by SIT and the patient's risk profile. If peri‐implantitis occurred, 11 treatment strategies (non‐surgical or surgical debridement alone or combined with adjunct therapies) were compared. Treatments and risk profiles determined disease progression. Modeling was performed based on systematically collected data. Primary outcomes were costs and proportion of lost implants, as assessed via Monte Carlo microsimulations. Results: Not providing SIT and performing only non‐surgical debridement was both least costly and least effective. The next best (more costly and effective) option was to provide SIT and perform surgical debridement (additional 0.89 euros per 1% fewer implants lost). The most effective option included bone grafts, membranes, and laser treatment (56 euros per 1%). For patients at high risk, the cost‐effectiveness of SIT increased, whereas in low‐risk groups, a cost‐optimized strategy was cost‐effective. Conclusions: Although clinical decision‐making will be guided mainly by clinical condition, cost‐effectiveness analyses might add another perspective. Based on these findings, an unambiguous comparative effectiveness ranking was not established. However, cost‐effectiveness was predominantly determined by provision of SIT and initial treatment costs. Transferability of these findings to other healthcare systems needs further confirmation.     

Clinical Outcomes of Using Lasers for Peri‐Implantitis Surface Detoxification: A Systematic Review and Meta‐Analysis

The aim of this systematic review is to compare the clinical outcomes of lasers with other commonly applied detoxification methods for treating peri‐implantitis. An electronic search of four databases and a hand search of peer‐reviewed journals for relevant articles were conducted. Comparative human clinical trials and case series with ≥6 months of follow‐up in ≥10 patients with peri‐implantitis treated with lasers were included. Additionally, animal studies applying lasers for treating peri‐implantitis were also included. The included studies had to report probing depth (PD) reduction after the therapy. Results: Seven human prospective clinical trials and two animal studies were included. In four and three human studies, lasers were accompanied with surgical and non‐surgical treatments, respectively. The meta‐analyses showed an overall weighted mean difference of 0.00 mm (95% confidence interval = ?0.18 to 0.19 mm) PD reduction between the laser and conventional treatment groups (P = 0.98) for non‐surgical intervention. In animal studies, laser‐treated rough‐surface implants had a higher percentage of bone‐to‐implant contact than smooth‐surface implants. In a short‐term follow‐up, lasers resulted in similar PD reduction when compared with conventional implant surface decontamination methods.     

The Current Weight of Evidence of the Microbiologic Profile Associated With Peri‐Implantitis: A Systematic Review

Background: There is currently no consensus regarding microorganisms that may be considered true peri‐implant pathogens. Therefore, the aim of this systematic review is to determine the weight of evidence for microorganisms related to peri‐implantitis based on results of association studies. Methods: This review was performed following the Preferred Reporting Items for Systematic Reviews and MetaAnalyses (PRISMA). Two independent researchers searched PubMed/Medline, Embase, and Cochrane Library databases up to August 4, 2015, for studies comparing microbiologic outcomes of subgingival biofilm samples from healthy implants and implants with peri‐implantitis. Results: A total of 799 titles was identified and 11 studies were included in this review. All data were extracted using a predefined form. Microorganisms found in increased count/abundance/frequency in peri‐implantitis belonged to Bacteria domain and viruses, and included a total of six bacterial phyla, 17 bacterial genera, 23 bacterial species, and two genera of viruses. The main bacterial species associated with peri‐implantitis are recognized as periodontal pathogens. Conclusion: Results of this systematic review suggest moderate evidence supporting association of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia and some evidence supporting association of Prevotella intermedia and Campylobacter rectus with the etiology of peri‐implantitis.     

The Peri‐Implantitis: Implant Surfaces,Microstructure, and Physicochemical Aspects

There are two ways of looking at secondary failures of osseointegration; one is to reflect on possible causes for the failure, the other focuses on the pathology per se. In the first case, background factors such as mechanical trauma (adverse loading) or inflammations/infections are being discussed as the cause of failure. Then peri‐implantitis is a term reserved for implant disturbance due to inflammation/infections only. However, irrespective of the original reason for the failure being adverse loading or inflammation/infection, the end result with bone resorption and inflammation may be very similar. Hence, in the present article, an alternative outlook has been chosen. Trigerring factors for peri‐implantitis are generally gathered under four categories: lesions of peri‐implant attachment, presence of aggressive bacteria, excessive mechanical stress, and corrosion. If only one of these factors would start a chain reaction leading to lesions, then the other factors may combine to worsen the condition. With other words, peri‐implantitis is a general term dependent on a synergy of several factors, irrespective of the precise reason for first triggering off symptoms.     

Patient‐Centered Perspectives and Understanding of Peri‐Implantitis

Background: Patients undergoing dental treatment have an uncertain understanding about dental implant therapy and its complications. Therefore, the aims of this study assess the following: 1) level of knowledge, awareness, and attitudes about peri‐implantitis; 2) information provided by dentists/specialists who perform the treatment; and 3) perceptions, level of satisfaction, and impact on patient quality of life (QoL). Methods: Patients with implant restorative therapy currently undergoing peri‐implant maintenance therapy were recruited. Participants completed an anonymous questionnaire that included general aspects of prognosis, including the following: 1) peri‐implantitis; 2) etiology; 3) awareness; 4) attitudes; 5) treatment; 6) prevention; 7) risk factors; 8) quality of information; 9) level of patient satisfaction; and 10) QoL. Associations among questionnaire data were identified using univariate and multivariate analyses. Results: Overall, 411 implants were included from 135 patients with implants. Frequency of peri‐implantitis in the survey was 17.8% at the participant level, with 70% of them reporting high level of post‐surgical satisfaction. Worry and concern were frequent findings among patients with peri‐implantitis (64%), and 32% reported that living with the disease was terrible. The vast majority of patients (74.1%) did not have knowledge about peri‐implant pathology. Patients with peri‐implantitis showed statistically significantly better understanding of implant therapy (P <0.001) and also higher average concern (P = 0.004). Conclusions: Patients generally have a poor understanding and perception of peri‐implantitis and its impact. QoL was impaired by the presence of peri‐implantitis with high level of concern and low level of therapeutic satisfaction. Therefore, it is important to develop standardized information brochures to educate patients on risk factors and indicators of the disease to assist in the prevention of peri‐implantitis.     

Investigation of the Association Between Cement Retention and Prevalent Peri‐Implant Diseases: A Cross‐Sectional Study

Background: The aim of this study is to examine the association between retention type (cement‐retained versus screw‐retained restorations) and prevalence of peri‐implant diseases in a German university‐treated population. Methods: Data were analyzed from individuals that underwent clinical and radiographic peri‐implant examinations as part of a university‐based cross‐sectional study from September 2011 to October 2012. Results: Data from 139 individuals (mean age: 57.59 years) having 394 implants were analyzed: 192 implants supporting single crowns and 202 fixed partial dentures. Overall, 11.9% of the participants had peri‐implantitis, whereas 68.9% had peri‐implant mucositis. Crude odds ratios (95% confidence intervals) for peri‐implantitis and peri‐implant mucositis for cement‐ versus screw‐retained restorations were 1.43 (0.45, 4.60) and 0.89 (0.53, 1.48), respectively. Results remained non‐significant in multivariable models adjusting for type of restoration and smoking (all P values >0.50). There was also no effect of splinting restorations on disease prevalence in adjusted analyses (P values >0.32). Conclusions: In this university‐treated sample, there is no association between the type of prosthesis retention and peri‐implant diseases. Current findings show that, when appropriate selection and removal of cement is performed, cement retention is not a risk indicator for peri‐implant diseases.     

rgpA DNA Vaccine Induces Antibody Response and Prevents Alveolar Bone Loss in Experimental Peri‐Implantitis

Background: Peri‐implantitis is one of many reasons for dental implant failure. This study is designed to prevent experimental peri‐implantitis by arginine‐specific gingipain A (rgpA) DNA vaccine. Methods: The bilateral mandibular second and third premolars from 15 male beagle dogs were extracted, and 60 implants were immediately implanted. Three months after implantation, the animals were randomly divided into groups A, B, and C and immunized with plasmid vector–rgpA, heat‐killed Porphyromonas gingivalis, and plasmid vector, respectively. Cotton ligatures infiltrated with P. gingivalis were placed in the submarginal position around the neck of the implants to induce peri‐implantitis. Clinical measurements, including probing depth (PD) and bleeding on probing, were recorded every 2 weeks postoperatively, and P. gingivalis–specific immunoglobulin G (IgG) in serum and secretory IgA (sIgA) in saliva were quantitatively analyzed by enzyme‐linked immunosorbent assay at the same time. Animals were sacrificed after 6 weeks, 50‐μm undecalcified histologic sections were prepared using methylene blue dye, and bone loss around implants was measured. Results: Higher levels of IgG in serum and sIgA in saliva could be measured in groups A and B but not in group C after immunization. There were statistical differences (P <0.05) between, before, and after immunization, but no difference was found between groups A and B (P >0.05). Both peri‐implant PD and bone loss in group A were significantly less than in groups B and C. Conclusions: IgG and sIgA could be generated by immunization with rgpA DNA vaccine, which could significantly slow down bone loss in the experimental peri‐implantitis canine model.     

Microbial Characteristics of Peri‐Implantitis: A Case‐Control Study

Background: The aim of this case‐control study is to compare oral microbiologic characteristics of patients with healthy peri‐implant conditions and patients with peri‐implantitis and to explore the influence of various patient‐ and implant‐related factors on microbiologic characteristics. Methods: Peri‐implant submucosal microbial samples were collected from 85 patients with peri‐implantitis (cases) and from 69 patients with only implants with healthy peri‐implant conditions (controls). Samples were analyzed using culturing techniques. Multivariable logistic regression was used to explore the association of disease status and various patient‐ and implant‐related factors (sex, patient age, smoking, number of remaining teeth, percentage of teeth with bone loss, implant function time, implant surface, and presence of plaque) with microbiologic characteristics. Results: Peri‐implant disease status was significantly associated with the submucosal presence of Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Tannerella forsythia (Tf), and Fusobacterium nucleatum (Fn). The association with disease status was most obvious for Pi (odds ratio [OR]: 15.1; 95% confidence interval [CI]: 5.1 to 45.3) and Tf (OR: 13.3; 95% CI: 5.4 to 32.5). The prevalence of Aggregatibacter actinomycetemcomitans and Staphylococcus species was very low. Conclusions: The periodontal pathogens Pg, Pi, Tf, and Fn are associated with peri‐implantitis. A. actinomycetemcomitans and Staphylococcus species do not seem to play an important role in peri‐implantitis.     

kgp,rgpA, and rgpB DNA Vaccines Induce Antibody Responses in Experimental Peri‐Implantitis

Background: Peri‐implantitis is the key factor for implant failure. This study aims to evaluate kgp, rgpA, and rgpB DNA vaccines to induce an immune response and prevent peri‐implantitis. Methods: The kgp, rgpA, and rgpB genes were amplified by polymerase chain reaction (PCR) from Porphyromonas gingivalis (Pg) ATCC 33277 and cloned into the pVAX1 vector. Titanium implants were placed into the mandibular bone of dogs. Three months later, the animals were divided into four groups, immunized with pVAX1‐kgp, pVAX1‐rgpA, pVAX1‐rgpB, or pVAX1. Cotton ligatures infiltrated with Pg were tied around the neck of the implants. Immunoglobulin (Ig)G and IgA antibodies were detected by enzyme‐linked immunosorbent assay before and after immunization. Results: The kgp, rgpA, and rgpB genes were successfully cloned into the pVAX1 plasmid. Animals immunized with pVAX1‐kgp and pVAX1‐rgpA showed higher titers of IgG and IgA antibodies compared to those before immunization (P <0.05) and compared to those that were immunized with pVAX1 and pVAX1‐rgpB, whereas there were no significant differences in the animals treated with pVAX1 and pVAX1‐rgpB. Furthermore, among these, the kgp DNA vaccine was more effective. The bone losses of the groups with pVAX1‐kgp and pVAX1‐rgpA were significantly attenuated. Conclusion: pVAX1‐kgp and pVAX1‐rgpA DNA vaccines enhanced immunity responses and significantly retarded bone loss in experimental peri‐implantitis animal models, whereas pVAX1‐rgpB was ineffective.     

Prevalence,Etiology and Treatment of Peri‐Implant Mucositis and Peri‐Implantitis: A Survey of Periodontists in the United States

Background: Currently, information available on the exact prevalence and standard therapeutic protocol of peri‐implant diseases is insufficient. The aim of this survey was to investigate the perceived prevalence, etiology, and management of peri‐implant mucositis and peri‐implantitis by periodontists in the United States. Methods: A twenty‐question survey was developed. Periodontists currently practicing in the United States were contacted by an e‐mail that contained a link to access the survey. Results: Two hundred eighty periodontists (79.3% males; 62.9% with >10 years in practice, 75.7% in private practice) completed the survey. Most (96.1%) of the participants were placing implants (58.3% for >10 years and 32.4% >150 implants/year). The majority reported that the prevalence of peri‐implant mucositis and peri‐implantitis in their practices is up to 25% but is higher in the general US population and that up to 10% of implants must be removed due to peri‐implantitis. There was agreement among contributing etiologic factors such as: 1) plaque; 2) smoking; 3) adverse loading; 4) oral hygiene; 5) use of antimicrobial gel/mouthrinse; 6) non‐surgical debridement; 7) use of systemic antibiotics; and 8) 3‐month supportive care for treatment of peri‐implantitis. Significant heterogeneity was recorded in relation to the instruments used for debridement, use and type of surgical treatment, and materials used for regeneration. Only 5.1% believed that treatment is very effective. Conclusions: This survey indicates that peri‐implant diseases are a frequently encountered problem in periodontal practices and that the absence of a standard therapeutic protocol results in significant empirical use of therapeutic modalities and a moderately effective treatment outcome.