Composition of supra- and subgingival biofilm of subjects with healthy and diseased implants

Objectives: The purpose of this study was to compare the microbial composition of supra‐ and subgingival biofilm in subjects with and without peri‐implantitis. Material and methods: Forty‐four subjects (mean age 48.9 ± 13.51 years) with at least one implant restored and functional for at least 2 years were assigned to two groups: a peri‐implantitis group (n=22), consisting of subjects presenting peri‐implant sites with radiographic defects >3 mm, bleeding on probing and/or suppuration; and a control group (n=22), consisting of subjects with healthy implants. The clinical parameters evaluated were plaque index, gingival bleeding, bleeding on probing, suppuration, probing depth and clinical attachment level. Supra‐ and subgingival biofilm samples were taken from the deepest sites of each implant and analyzed for the presence of 36 microorganisms by checkerboard DNA–DNA hybridization. Results: Higher mean counts of Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia were observed in the peri‐implantitis group, both supra‐ and subgingivally (P<0.05). The proportions of the pathogens from the red complex were elevated, while host‐compatible beneficial microbial complexes were reduced in diseased compared with healthy implants. The microbiological profiles of supra‐ and subgingival environments did not differ substantially within each group. Conclusion: Marked differences were observed in the composition of supra‐ and subgingival biofilm between healthy and diseased implants. The microbiota associated with peri‐implantitis was comprised of more periodontal pathogenic bacterial species, including the supragingival biofilm.     

Association of the composite IL-1 genotype with peri-implantitis: a systematic review

Objective: Cytokine gene polymorphisms may modulate the host response to the bacterial challenge and influence susceptibility to peri‐implantitis. Objective: To systematically review the evidence of an association between the interleukin‐1 (IL‐1) composite genotype, i.e. presence of the allele 2 in the gene clusters IL‐1A (?889) and in IL‐1B (+3953), and peri‐implantitis. Material and methods: An electronic search in the National Library of Medicine‐computerized bibliographic database MEDLINE and a manual search were performed. The search was conducted for longitudinal clinical trials comparing progression of peri‐implantitis in IL‐1 genotype positive (carrying allele 2) with IL‐1 genotype negative (not carrying allele 2) subjects. Selection of publications, extraction of data and validity assessment were made independently by two reviewers. Results: The search provided 44 titles of which two longitudinal publications were included. Conclusion: Based on the findings from this study, there is not enough evidence to support or refute an association between the IL‐1 genotype status and peri‐implantitis. Systematic genetic testing for the assessment of the risk of peri‐implantitis cannot be recommended as a standard of care at this time.     

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.     

A Novel Rat Model of Polymicrobial Peri‐Implantitis: A Preliminary Study

Background: Peri‐implantitis is a complex polymicrobial biofilm‐induced inflammatory osteolytic gingival infection that results in orofacial implant failures. To the best knowledge of the authors, there are no preclinical in vivo studies in implant dentistry that have investigated the inflammatory response to known microbial biofilms observed in humans. The aim of this study is to develop a novel peri‐implant rat model using an established model of polymicrobial periodontitis. Methods: Wistar rats were used for the study of experimental peri‐implantitis. One month after extraction of maxillary first molars, a titanium mini‐implant was inserted. Two months after implant healing, implants were uncovered, and abutment fixing was done using cyanoacrylate to prevent abutment loosening. Rats were separated into two groups (group A: polymicrobial‐infected and group B: sham‐infected). One week after healing of abutments, rats were infected with Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia for 12 weeks. Bacterial colonization, bone resorption, and implant inflammation were evaluated by polymerase chain reaction (PCR), microcomputed tomography, and histology, respectively. Results: Three rats with four implants in the infection group and two rats with three implants in the sham‐infection group were analyzed. PCR analysis revealed presence of bacterial genomic DNA, and infection elicited significant immunoglobulin (Ig)G and IgM antibody responses, indicating bacterial colonization/infection around implants. Infection induced an enhanced mean distance from implant platform to the first bone‐to‐implant contact, extensive peri‐implantitis with advanced bone resorption, and extensive inflammation with granulation tissue and polymorphonuclear leukocytes. Conclusions: To the best knowledge of the authors, this is the first study to develop a novel rat model of polymicrobial peri‐implantitis. With modifications to improve implant retention it could offer significant advantages for studies of initiation and progression of peri‐implantitis.     

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.     

Periodontal and peri‐implant diseases: identical or fraternal infections?

Peri‐implant diseases (peri‐implantitis and peri‐implant mucositis) are bacterially driven infections. Peri‐implantitis leads to aggressive bone resorption and eventual loss of the implant. Traditionally, peri‐implantitis was regarded as microbially similar to periodontitis, and translocation of periodontal pathogens into the peri‐implant crevice was considered as a critical factor in disease causation. However, evidence is emerging to suggest that the peri‐implant and periodontal ecosystems differ in many important ways. The purpose of this review is to examine the evidence supporting microbial congruence and discordance in these two communities. Current evidence suggests that osseointegrated implants truly create unique microenvironments that force microbial adaptation and selection. Further studies that revisit the “microbial reservoir” hypothesis and identify species that play an etiologic role in peri‐implant disease and examine their transmission from teeth are needed.     

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.     

Transmission of Periodontopathic Bacteria from Natural Teeth to Implants

Purpose: Prevention of peri‐implantitis is essential for the success of implant rehabilitation. Infection by periodontopathic bacteria is a major cause of peri‐implantitis. The aim of the present study was to identify the source of peri‐implant colonization by periodontopathic bacteria. Materials and Methods: Twenty‐one patients with implants were enrolled in the study. Subgingival plaque samples from the adjacent, occluding, and contralateral natural teeth were collected prior to second‐stage surgery. Samples from implant sulci were then obtained 2 weeks later. Detection of periodontopathic bacteria was performed by the polymerase chain reaction. Results: The detection rates for Aggregatibacter actinomycetemcomitans, Prevotella intermedia, Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, and Fusobacterium nucleatum in all subgingival samples from natural teeth were similar to that in the peri‐implant sulci. Multiple logistic regression analysis revealed an association between the detection of A. actinomycetemcomitans, Prevotella intermedia, Porphyromonas gingivalis, Treponema denticola, and F. nucleatum in the gingival crevices of adjacent teeth and that of the peri‐implant sulcus, but no association for Tannerella forsythia. Conclusions: The present findings suggest that colonization by A. actinomycetemcomitans, Prevotella intermedia, Porphyromonas gingivalis, Treponema denticola, and F. nucleatum at the implant sulcus was affected by these microorganisms in the gingival crevice of adjacent teeth rather than those on occluding and contralateral teeth.     

IL-1RN gene polymorphism is associated with peri-implantitis

Objectives: Interleukin (IL)‐1α, IL‐1β and their natural specific inhibitor IL‐1 receptor antagonist (IL‐1ra) play a key role in the regulation of the inflammatory response in periodontal tissues. Polymorphisms in the IL‐1 gene cluster have been associated with severe adult periodontitis. We aimed to investigate the IL‐1 gene cluster polymorphisms in patients with peri‐implantitis. Material and methods: The study included 120 North Caucasian individuals. A total of 71 patients (mean age 68 years, 76% smokers) demonstrating peri‐implantitis at one or more implants as evidenced by bleeding and/or pus on probing and bone loss amounting to >3 threads on Brånemark implants and 49 controls (mean age 66 years, 45% smokers) with clinical healthy mucosa and no bone loss around the implants were recruited for the study. The titanium implants, ad modum Brånemark, had been in function for at least 2 years. Mouthwash samples were collected and used for genotyping of the bi‐allelic polymorphisms IL‐1A^?889, IL‐1B⁺³⁹⁵³, IL‐1B^?511 and a variable number of tandem repeat IL‐1RN gene polymorphisms using PCR technique. Results: Significant differences were found in the carriage rate of allele 2 in the IL‐1RN gene between peri‐implantitis patients and controls (56.5% vs. 33.3%, respectively; odds ratios (OR) 2.6; 95% confidence interval (CI) 1.2–5.6; P=0.015). Logistic regression analysis taking smoking, gender and age into account confirmed the association between the IL‐1RN allele 2 carriers and peri‐implantitis (OR 3; 95% CI 1.2–7.6; P=0.02). Conclusions: Our results provide evidence that IL‐1RN gene polymorphism is associated with peri‐implantitis and may represent a risk factor for this disease.     

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.     

Epidemiology and risk factors of peri‐implantitis: A systematic review

The purpose of this systematic review and meta‐analysis was to assess the prevalence, incidence and risk factors of peri‐implantitis in the current literature. An electronic search was performed to identify publications from January 1980 until March 2016 on 9 databases. The prevalence and incidence of peri‐implantitis were assessed in different subgroups of patients and the prevalences were adjusted for sample size (SSA) of studies. For 12 of 111 identified putative risk factors and risk indicators, forest plots were created. Heterogeneity analysis and random effect meta‐analysis were performed for selected potential risk factors of peri‐implantitis. The search retrieved 8357 potentially relevant studies. Fifty‐seven studies were included in the systematic review. Overall, the prevalence of peri‐implantitis on implant level ranged from 1.1% to 85.0% and the incidence from 0.4% within 3 years, to 43.9% within 5 years, respectively. The median prevalence of peri‐implantitis was 9.0% (SSA 10.9%) for regular participants of a prophylaxis program, 18.8% (SSA 8.8%) for patients without regular preventive maintenance, 11.0% (SSA 7.4%) for non‐smokers, 7.0% (SSA 7.0%) among patients representing the general population, 9.6% (SSA 9.6%) for patients provided with fixed partial dentures, 14.3% (SSA 9.8%) for subjects with a history of periodontitis, 26.0% (SSA 28.8%) for patients with implant function time ≥5 years and 21.2% (SSA 38.4%) for ≥10 years. On a medium and medium‐high level of evidence, smoking (effect summary OR 1.7, 95% CI 1.25‐2.3), diabetes mellitus (effect summary OR 2.5; 95% CI 1.4‐4.5), lack of prophylaxis and history or presence of periodontitis were identified as risk factors of peri‐implantitis. There is medium‐high evidence that patient’s age (effect summary OR 1.0, 95% CI 0.87‐1.16), gender and maxillary implants are not related to peri‐implantitis. Currently, there is no convincing or low evidence available that identifies osteoporosis, absence of keratinized mucosa, implant surface characteristics or edentulism as risk factors for peri‐implantitis. Based on the data analyzed in this systematic review, insufficient high‐quality evidence is available to the research question. Future studies of prospective, randomized and controlled type including sufficient sample sizes are needed. The application of consistent diagnostic criteria (eg, according to the latest definition by the European Workshop on Periodontology) is particularly important. Very few studies evaluated the incidence of peri‐implantitis; however, this study design may contribute to examine further the potential risk factors.     

The Frequency of Peri‐Implant Diseases: A Systematic Review and Meta‐Analysis

Background: The peri‐implant diseases, namely peri‐implant mucositis and peri‐implantitis, have been extensively studied. However, little is known about the true magnitude of the problem, owing mainly to the lack of consistent and definite diagnostic criteria used to describe the condition. The objective of the present review is to systematically estimate the overall frequency of peri‐implant diseases in general and high‐risk patients. Methods: The systematic review is prepared according to the Meta‐analysis of Observational Studies in Epidemiology statement. Studies were searched in four electronic databases, complemented by manual searching. The quality of the studies was assessed according to Strengthening the Reporting of Observational Studies in Epidemiology, and the data were analyzed using statistical software. Results: Of 504 studies identified, nine studies with 1,497 participants and 6,283 implants were included. The summary estimates for the frequency of peri‐implant mucositis were 63.4% of participants and 30.7% of implants, and those of peri‐implantitis were 18.8% of participants and 9.6% of implants. A higher frequency of occurrence of peri‐implant diseases was recorded for smokers, with a summary estimate of 36.3%. Supportive periodontal therapy seemed to reduce the rate of occurrence of peri‐implant diseases. Conclusions: Peri‐implant diseases are not uncommon following implant therapy. Long‐term maintenance care for high‐risk groups is essential to reduce the risk of peri‐implantitis. Informed consent for patients receiving implant treatment must include the need for such maintenance therapy.     

The evaluation of peri‐implant sulcus fluid osteocalcin,osteopontin, and osteonectin levels in peri‐implant diseases

1 Background

Peri‐implant mucositis is an inflammation of the soft tissues surrounding an implant. Peri‐implantitis refers to a process characterized by peri‐implant bone loss along with an inflammation of the soft tissues. Osteocalcin, osteopontin, and osteonectin proteins are related to bone remodeling. The aim of the present study was to investigate peri‐implant sulcus fluid (PISF) osteocalcin, osteopontin, and osteonectin levels in peri‐implant mucositis and peri‐implantitis.

2 Methods

Fifty‐two implants with peri‐implantitis, 46 implants with peri‐implant mucositis, and 47 control implants were included in the study. Clinical parameters including probing depth, modified sulcus bleeding index and modified plaque index were recorded. PISF osteocalcin, osteopontin, and osteonectin levels were analyzed by ELISA kits.

3 Results

There were no significant differences in PISF osteocalcin, osteopontin, and osteonectin total amounts between healthy controls, peri‐implant mucositis and peri‐implantitis groups (P > 0.05). Probing depths were not correlated with PISF osteocalcin, osteopontin, and osteonectin levels in the study groups (P > 0.05).

4 Conclusions

Soft tissue inflammation around dental implants does not cause a change in osteocalcin, osteopontin, and osteonectin levels in PISF. Also, peri‐implantitis does not seem to give rise to an increase in PISF levels of osteocalcin, osteopontin, and osteonectin.     

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.     

Outcome of surgical treatment of peri-implantitis: results from a 2-year prospective clinical study in humans

Aim: The aim of the present study was to evaluate the outcome of a surgical procedure based on pocket elimination and bone re‐contouring for the treatment of peri‐implantitis. Material and methods: The 31 subjects involved in this study presented clinical signs of peri‐implantitis at one or more dental implants (i.e. ≥6 mm pockets, bleeding on probing and/or suppuration and radiographic evidence of ≥2 mm bone loss). The patients were treated with a surgical procedure based on pocket elimination and bone re‐contouring and plaque control before and following the surgery. At the time of surgery, the amount of bone loss at implants was recorded. Results: Two years following treatment, 15 (48%) subjects had no signs of peri‐implant disease; 24 patients (77%) had no implants with a probing pocket depth of ≥6 mm associated with bleeding and/or suppuration following probing. A total of 36 implants (42%) out of the 86 with initial diagnosis of peri‐implantitis presented peri‐implant disease despite treatment. The proportion of implants that became healthy following treatment was higher for those with minor initial bone loss (2–4 mm bone loss as assessed during surgery) compared with the implants with a bone loss of ≥5 mm (74% vs. 40%). Among the 18 implants with bone loss of ≥7 mm, seven were extracted. Between the 6‐month and the 2‐year examination, healthy implants following treatment tended to remain stable, while deepening of pockets was observed for those implants with residual pockets. Conclusion: The results of this study indicated that a surgical procedure based on pocket elimination and bone re‐contouring and plaque control before and following surgery was an effective therapy for treatment of peri‐implantitis for the majority of subjects and implants. However, complete disease resolution at the site level seems to depend on the initial bone loss at implants. Implants with no signs of peri‐implantitis following treatment tended to remain healthy during the 2‐year period, while a tendency for disease progression was observed for the implants that still showed signs of peri‐implant disease following treatment. To cite this article:
Serino G, Turri A. Outcome of surgical treatment of peri‐implantitis: results from a 2‐year prospective clinical study in humans.
Clin. Oral Impl. Res. 22 , 2011; 1214–1220.
doi: 10.1111/j.1600‐0501.2010.02098.x     

Peri-implantitis in partially edentulous patients: association with inadequate plaque control

Objective: The aim of the present study was to describe some clinical periodontal features of partially edentulous patients referred for the treatment of peri‐implantitis. Material and methods: The 23 subjects involved in this study were selected from consecutive patients referred to the department of Periodontology Södra Älvsborgs Hospital, Borås, Sweden, for treatment of peri‐implantitis during 2006. The patients had clinical signs of peri‐implantitis around one or more dental implants (i.e.≥6 mm pockets, bleeding on pockets and/or pus and radiographic images of bone loss to≥3 threads of the implants) and remaining teeth in the same and/or opposite jaw. The following clinical variables were recorded: Plaque Index (PI), Gingival Bleeding Index (GBI) Probing Pocket Depth (PPD), Access/capability to oral hygiene at implant site (yes/no), Function Time. The patients were categorized in the following sub‐groups: Periodontitis/No periodontitis, Bone loss/No bone loss at teeth, Smoker/Non‐smokers. Results: Out of the 23 patients, the majority (13) had minimal bone loss at teeth and no current periodontitis; 5 had bone loss at teeth exceeding 1/3 of the length of the root but not current periodontitis and only 5 had current periodontitis. Six patients were smokers (i.e. smoking more than 10 cig/day). The site level analysis showed that only 17 (6%) of the 281 teeth present had ≥1 pocket of ≥6mm, compared to 58 (53%) of the total 109 implants (28 ITI^® and 81 Brånemark^®); 74% of the implants had no accessibility to proper oral hygiene. High proportion of implants with diagnosis of peri‐implantitis were associated with no accessibility/capability for appropriate oral hygiene measures, while accessibility/capability was rarely associated with peri‐implantitis. Indeed 48% of the implants presenting peri‐implantitis were those with no accessibility/capability for proper oral hygiene (65% positive predict value) with respect to 4% of the implants with accessibility/capability (82% negative predict value). Conclusion: The results of the study indicate that local factors such as accessibility for oral hygiene at the implant sites seems to be related to the presence or absence of peri‐implantitis. Peri‐implantitis was a frequent finding in subjects having signs of minimal loss of supporting bone around the remaining natural dentition and no signs of presence of periodontitis (i.e. presence of periodontal pockets of ≥6 mm at natural teeth). Only 6 of the examinated subjects were smokers. In view of these results we should like to stress the importance of giving proper oral hygiene instructions to the patients who are rehabilitated with dental implant and of proper prosthetic constructions that allow accessibility for oral hygiene around implants.     

Microbial Colonization of the Peri‐Implant Sulcus and Implant Connection of Implants Restored With Cemented Versus Screw‐Retained Superstructures: A Cross‐Sectional Study

Background: The aim of this study is to investigate peri‐implant and intraconnection microflora of healthy implants restored with cemented and screwed superstructures. Methods: Patients with two to three implants restored with cemented or screwed restorations and 5 years of follow‐up were recruited. Samples were taken from peri‐implant sulci, adjacent teeth, and the inner portion of connections. Prevalence of positive sites and bacterial loads for 10 microorganisms were obtained with quantitative real‐time polymerase chain reaction. Implant connection permeability to the studied microorganisms was estimated using a standardized bacterial contamination index. Statistical analysis was performed using a generalized estimating equations model, Wald χ² test, and the least significant difference test. Results: The final sample consisted of 18 patients (55 implants) in the cemented group and 22 patients (46 implants) in the screw‐retained group. Regarding prevalence of positive sites, significant differences between groups were only found for Tannerella forsythia, which was 8.7 times more frequent at peri‐implant sulci of cemented than screw‐retained prostheses. Bacterial loads of Porphyromonas gingivalis, T. forsythia, Parvimonas micra, and total bacterial load were significantly higher at peri‐implant sulci for the cemented group; at the inner portion of connections, values were significantly higher for P. micra and Fusobacterium nucleatum for the screw‐retained group. Contamination index values demonstrated higher permeability to most microbes in the cemented group. Conclusions: Internal implant surfaces were microbiologically contaminated for both cemented and screw‐retained superstructures. Differences were found between the two methods of prosthetic retention: the cemented group presented significantly higher bacterial loads in the peri‐implant sulcus but significantly lower bacterial loads at the inner portion of the implant connection.     

Tenascin-C and matrix metalloproteinase-9 levels in crevicular fluid of teeth and implants

Background: The role of and interaction between bacterial infection and biomechanical impact in the development of peri‐implant inflammatory processes is not clear. Objective: To determine the amount and concentration of tenascin‐C (TNC) in gingival crevicular fluid (GCF) around teeth and in peri‐implant sulcus fluid from healthy implants and implants with peri‐implantitis, and to correlate it with matrix metalloproteinase‐9 (MMP‐9) levels. Materials and Methods: Seven control individuals and 18 patients with 41 implants with/without peri‐implantitis were included. GCF was collected with filter strips and volumes were measured with a Periotron device. The amount of serum albumin per sample was quantified by densitometric analysis of Coomassie‐stained sodium dodecyl sulfate–polyacrylamide gel electrophoresis. Relative activity of MMP‐9 was determined from the densitometry of zymograms. Amounts and concentrations of TNC were evaluated by ELISA. Results: Relative MMP‐9 activity was increased in peri‐implantitis. A tendency was observed to measure higher TNC concentrations at teeth than at implants. The amount of TNC in GCF collected from healthy implant sites and the peri‐implantitis sites was significantly different. Based on immunoblotting, TNC in GCF seemed degraded. In contrast to TNC, MMP‐9 was significantly related to the PD and the volume of GCF. Conclusion: TNC is known to be induced in inflammation. The increase found in peri‐implantitis was less than expected. In the context of peri‐implantitis, TNC might be a marker of bone remodelling rather than inflammation and infection. A possible proteolytic degradation of TNC during peri‐implantitis needs to be studied.