Etiology, pathogenesis and treatment of peri-implantitis: A European perspective.

Peri-implantitis is a plaque-associated pathological condition occurring in tissues around dental implants. It is characterized by inflammation in the peri-implant mucosa and progressive loss of supporting bone. Over the last 30 years, peri-implantitis has become a major disease burden in dentistry. An understanding of the diagnosis, etiology and pathogenesis, epidemiology, and treatment of peri-implantitis must be a central component in undergraduate and postgraduate training programs in dentistry. In view of the strong role of European research in periodontology and implant dentistry, the focus of this review was to address peri-implantitis from a European perspective. One component of the work was to summarize new and reliable data on patients with dental implants to underpin the relevance of peri-implantitis from a population perspective. The nature of the peri-implantitis lesion was evaluated through results presented in preclinical models and evaluations of human biopsy material together with an appraisal of the microbiological characteristics. An overview of strategies and outcomes presented in clinical studies on nonsurgical and surgical treatment of peri-implantitis is discussed with a particular focus on end points of therapy and recommendations presented in the S3 level Clinical Practice Guideline for the prevention and treatment of peri-implant diseases.

Long-term outcomes and prognostic factors of surgical treatment of peri-implantitis - A retrospective study.

AIM: To evaluate long-term outcomes and prognostic factors of non-reconstructive surgical treatment of peri-implantitis. MATERIALS AND METHODS: One hundred forty-nine patients (267 implants) were surgically treated for peri-implantitis and followed for an average of 7.0 (SD: 3.6) years. The primary outcome was implant loss. Additional bone loss and surgical retreatment were secondary outcomes. Patient/implant characteristics, as well as clinical and radiographic parameters collected prior to initial surgery, were evaluated as potential predictors of implant loss. Flexible parametric survival models using restricted cubic spline functions were used; 5- and 10-year predicted rates of implant loss were calculated according to different scenarios. RESULTS: Fifty-three implants (19.9%) in 35 patients (23.5%) were lost during the observation period. Implant loss occurred after a mean period of 4.4 (SD: 3.0) years and was predicted by implant surface characteristics (modified surface; HR 4.5), implant length (HR 0.8 by mm), suppuration at baseline (HR 2.7) and disease severity (baseline bone loss: HR 1.2 by mm). Estimates of 5- and 10-year implant loss ranged from 1% (best prognostic scenario; initial bone loss <40% of implant length, turned implant surface and absence of suppuration on probing (SoP)) to 63% (worst prognostic scenario; initial bone loss ≥60% of implant length, modified implant surface and SoP) and from 3% to 89%, respectively. Surgical retreatment was performed at 65 implants (24.3%) in 36 patients (24.2%) after a mean time period of 4.5 (3.1) years. In all, 59.5% of implants showed additional bone loss, were surgically retreated or lost. CONCLUSIONS: Recurrence of disease is common following surgical treatment of peri-implantitis. The strongest predictor for implant loss was implant surface characteristics. Implant length as well as suppuration and disease severity at baseline were also relevant factors.

Decontamination of biofilm-contaminated implant surfaces: An in vitro evaluation.

OBJECTIVES: The aim of the present study was to evaluate the cleaning efficacy of two mechanical and two chemical protocols in the decontamination of implant surfaces. METHODS: In total, 123 commercially available implants were mounted in plastic models mimicking peri-implant circumferential intra-bony defects. A multispecies biofilm was grown on implant surfaces. Mechanical (air-polishing (AP), rotating titanium brush (TiB)) and chemical decontamination (alkaline electrolyzed water, N-acetyl-L-cysteine) protocols were used. Cleaning efficacy in terms of residual biofilm area, chemical surface properties, and bacterial counts were analyzed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and quantitative polymerase chain reaction. RESULTS: Surface decontamination protocols including use of an AP device or a rotating TiB were superior in terms of biofilm removal and in reducing atomic% of Carbon on implant surfaces when compared to methods restricted to wiping with gauze. The use of chemical agents as adjuncts to the mechanical cleaning protocols provided no relevant overall benefit over saline. No treatment modality, however, resulted in complete biofilm removal. CONCLUSION: Air-polishing and rotating TiB were more effective implant surface decontamination protocols than wiping with gauzes. Use of chemical agents did not improve cleaning efficacy.

Factors influencing outcomes of surgical therapy of peri-implantitis: A secondary analysis of 1-year results from a randomized clinical study.

AIM: To identify predictors of treatment outcomes following surgical therapy of peri-implantitis. MATERIALS AND METHODS: We performed a secondary analysis of data from a randomized controlled trial (RCT) comparing access flap with or without bone replacement graft. Outcomes at 12 months were probing pocket depth (PPD), bleeding on probing (BOP), soft-tissue recession (REC) and marginal bone level (MBL) change. Multilevel regression analyses were used to identify predictors. We also built an explanatory model for residual signs of inflammation. RESULTS: Baseline PPD was the most relevant predictor, showing positive associations with final PPD, REC and MBL gain, and negative association with probability of pocket closure. Smokers presented higher residual PPD. Absence of keratinized mucosa at baseline increased the probability of BOP but was otherwise not indicative of outcomes. Plaque at 6 weeks was detrimental in terms of residual PPD and BOP. Treatment allocation had an effect on REC. Final BOP was explained by residual PPD ≥6 mm and plaque at more than two sites. CONCLUSIONS: Baseline PPD was the most relevant predictor of the outcomes of surgical therapy of peri-implantitis. Pocket closure should be a primary goal of treatment. Bone replacement grafts may be indicated in aesthetically demanding cases to reduce soft-tissue recession. The importance of smoking cessation and patient-performed plaque control is also underlined.

Prevention and treatment of peri-implant diseases-The EFP S3 level clinical practice guideline.

BACKGROUND: The recently published Clinical Practice Guidelines (CPGs) for the treatment of stages I-IV periodontitis provided evidence-based recommendations for treating periodontitis patients, defined according to the 2018 classification. Peri-implant diseases were also re-defined in the 2018 classification. It is well established that both peri-implant mucositis and peri-implantitis are highly prevalent. In addition, peri-implantitis is particularly challenging to manage and is accompanied by significant morbidity. AIM: To develop an S3 level CPG for the prevention and treatment of peri-implant diseases, focusing on the implementation of interdisciplinary approaches required to prevent the development of peri-implant diseases or their recurrence, and to treat/rehabilitate patients with dental implants following the development of peri-implant diseases. MATERIALS AND METHODS: This S3 level CPG was developed by the European Federation of Periodontology, following methodological guidance from the Association of Scientific Medical Societies in Germany and the Grading of Recommendations Assessment, Development and Evaluation process. A rigorous and transparent process included synthesis of relevant research in 13 specifically commissioned systematic reviews, evaluation of the quality and strength of evidence, formulation of specific recommendations, and a structured consensus process involving leading experts and a broad base of stakeholders. RESULTS: The S3 level CPG for the prevention and treatment of peri-implant diseases culminated in the recommendation for implementation of various different interventions before, during and after implant placement/loading. Prevention of peri-implant diseases should commence when dental implants are planned, surgically placed and prosthetically loaded. Once the implants are loaded and in function, a supportive peri-implant care programme should be structured, including periodical assessment of peri-implant tissue health. If peri-implant mucositis or peri-implantitis are detected, appropriate treatments for their management must be rendered. CONCLUSION: The present S3 level CPG informs clinical practice, health systems, policymakers and, indirectly, the public on the available and most effective modalities to maintain healthy peri-implant tissues, and to manage peri-implant diseases, according to the available evidence at the time of publication.

Reconstructive surgical therapy of peri-implantitis: A multicenter randomized controlled clinical trial.

OBJECTIVE: To evaluate the potential benefit of the use of a bone substitute material in the reconstructive surgical therapy of peri-implantitis. METHODS: In this multicenter randomized clinical trial, 138 patients (147 implants) with peri-implantitis were treated surgically, randomized by coin toss to either a control (access flap surgery) or a test group (reconstructive surgery using bone substitute material). Clinical assessments, including probing pocket depth (PPD), bleeding and suppuration on probing (BOP & SOP) as well as soft tissue recession (REC), were recorded at baseline, 6 and 12 months. Marginal bone levels (MBL), measured on intra-oral radiographs, and patient-reported outcomes (PROs) were recorded at baseline and 12 months. No blinding to group allocation was performed. The primary outcome at 12 months was a composite measure including (i) implant not lost, (ii) absence of BOP/SOP at all aspects, (iii) PPD ≤5 mm at all aspects and (iv) ≤1 mm recession of mucosal margin on the buccal aspect of the implant. Secondary outcomes included (i) changes of MBL, (ii) changes of PPD, BOP%, and buccal KM, (iii) buccal REC and (iv) patient-reported outcomes. RESULTS: During follow-up, four implants (one in the test group, three in the control group) in four patients were removed due to disease progression. At 12 months, a total of 69 implants in the test and 68 implants in the control group were examined. Thus, 16.4% and 13.5% of implants in the test and control group, respectively, met all predefined criteria of the composite outcome. PPD reduction and MBL gain were 3.7 mm and about 1.0 mm in both groups. Reduction in mean BOP% varied between 45% (test) and 50% (control), without significant differences between groups. Buccal REC was less pronounced in the test group (M = 0.7, SD = 0.9 mm) when compared to controls (M = 1.1, SD = 1.5 mm). PROs were favorable in both groups without significant differences. One case of allergic reaction to the antibiotic therapy was recorded. No other adverse events were noted. CONCLUSIONS: Surgical therapy of peri-implantitis effectively improved the clinical and radiographic status at 12 months. While the use of a bone substitute material did not improve reductions of PPD and BOP, buccal REC was less pronounced in the test group. Patient satisfaction was high in both groups.

Cellular expression of epigenetic markers and oxidative stress in periodontitis lesions of smokers and non-smokers.

OBJECTIVE: To evaluate differences in the cellular expression of epigenetic markers and oxidative stress in periodontitis lesions between current smokers and non-smokers. BACKGROUND: Tobacco smoking is recognized as one of the major risk factors for periodontitis. However, the mechanisms by which smoking affects the progression of the disease remain to be determined. METHODS: Twenty-five current smokers and 21 non-smokers with generalized severe periodontitis were included. From each patient, one soft tissue biopsy from a periodontitis site was harvested and prepared for histological analysis. The infiltrated connective tissue (ICT) was selected as the region of interest to assess the cellular expression of epigenetic markers and reactive oxygen/nitrogen species (RONS) by immunohistochemistry. RESULTS: Although the ICT of smokers and non-smokers did not differ in size or in the expression of markers for DNA damage or oxidative stress, current smokers presented with significantly lower area proportions and densities of cells positive for the epigenetic markers DNMT1 and AcH3. In addition, periodontitis lesions in current smokers presented with a diminished antimicrobial activity, as indicated by significantly lower densities and area proportions of NOX2- and iNOS-positive cells. CONCLUSIONS: Components of the host response and epigenetic mechanisms in periodontitis lesions in smokers are downregulated as opposed to lesions of non-smokers.

Accuracy of bone-level assessments following reconstructive surgical treatment of experimental peri-implantitis.

AIMS: The purpose of this study was to evaluate the accuracy of bone-level assessments using either cone-beam computed tomography (CBCT), intra-oral peri-apical (PA) radiographs or histology following reconstructive treatment of experimental peri-implantitis. MATERIALS AND METHODS: Six Labrador dogs were used. Experimental peri-implantitis was induced 3 months after implant placement. Surgical treatment of peri-implantitis was performed and peri-implant defects were allocated to one of four treatment categories; no augmentation, bone graft materials with or without a barrier membrane. Six months later, intra-oral PA radiographs and block biopsies from all implants sites were obtained. Marginal bone levels (MBLs) were measured using PA radiographs, CBCT and histology. RESULTS: Significant correlations of MBL assessments were observed between the three methods. The measurements in PA radiographs consistently resulted in an overestimation of the bone level of about 0.3-0.4 mm. The agreement between the methods was not influenced by the use of bone substitute materials in the management of the osseous defects. CONCLUSIONS: Although MBL assessments obtained from PA radiographs showed an overestimation compared to MBL assessments on corresponding CBCT images and histological sections, PA radiographs can be considered a reliable technique for peri-implant bone-level evaluations following reconstructive surgical therapy of experimental peri-implantitis.

Surgical treatment of experimental peri-implantitis using mechanical and chemical decontamination procedures: A pre-clinical in vivo study.

AIM: To evaluate the effect of surgical treatment of experimental peri-implantitis at implants with different surface characteristics using mechanical and chemical decontamination methods. MATERIALS AND METHODS: Following extraction of mandibular premolars, four implants with two different surface characteristics (A, moderately rough and B, smooth) were placed in each side of the mandible of six dogs. Experimental peri-implantitis was induced. Surgical treatment of the peri-implantitis sites was carried out using four implant surface decontamination protocols: (i) deposition of a citric acid gel, (ii) mechanical cleaning using a rotating titanium brush, (iii) a combination of the mechanical and chemical procedures, and (iv) saline (control). Clinical and radiographic examinations were performed. Block biopsies were obtained 6 months after therapy and prepared for histological analysis. RESULTS: Irrespective of the treatment group, treatment resulted in 0.63 ± 0.92 and 0.65 ± 0.67 mm radiographic bone gain around implants A and B, respectively. Histological analyses revealed that persisting soft tissue inflammation as assessed using an infiltrated connective tissue (ICT) score was significantly lower at implant type B than at implant type A for all treatment groups. The test decontamination procedures did not demonstrate better results regarding resolution of peri-implantitis lesions, as indicated by the ICT scores, than the control procedure. The control treatment resulted in significantly superior outcomes of resolution of peri-implantitis lesions than the citric acid regimen. CONCLUSIONS: It is concluded that decontamination procedures including citric acid gel or rotating titanium brush did not improve outcomes following surgical treatment of experimental peri-implantitis. Results were, however, influenced by the implant surface characteristics.

Adopción/Adaptación para España de la Guía de Práctica Clínica de Nivel S3 de la Federación Europea de Periodoncia (EFP) - Tratamiento de la Periodontitis en Estadios I-III

Resumen Antecedentes: La clasificación de la periodontitis recientemente introducida en el World Workshop de 2017, que incorpora estadios y grados de la enfermedad, tiene por objeto vincular la clasificación de la enfermedad con los enfoques preventivos y terapéuticos, ya que no solo describe su gravedad y el alcance, sino también el grado de complejidad y el riesgo de un individuo. Por lo tanto, es necesario contar con directrices clínicas basadas en la evidencia que ofrezcan recomendaciones para tratar la periodontitis. Objetivo: El objetivo del presente proyecto fue desarrollar una Guía de Práctica Clínica (CPG, por sus siglas en inglés, clinical practice guideline) de nivel S3 para el tratamiento de la periodontitis en los estadios I-III. Material y métodos: Estas CPG S3 se elaboraron bajo los auspicios de la Federación Europea de Periodoncia (EFP), siguiendo la orientación metodológica de la Asociación de Sociedades Médico-Científicas de Alemania y la estructura Grading of Recommendations Assessment, Development and Evaluation (GRADE). El proceso, riguroso y transparente, incluyó la síntesis de las investigaciones relevantes en 15 revisiones sistemáticas encargadas de manera específica, la evaluación de la calidad y la solidez de la evidencia, la formulación de recomendaciones específicas, así como lograr un acuerdo, sobre esas recomendaciones, por parte de expertos destacados y una amplia base de partes interesadas. Resultados: Estas CPG S3 abordan el tratamiento de la periodontitis (estadios I, II y III) utilizando un enfoque gradual preestablecido del tratamiento que, según el estadio de la enfermedad, debe ser incremental, incluyendo en cada caso diferentes intervenciones. Se llegó a un acuerdo sobre las recomendaciones relativas a las diferentes intervenciones, dirigidas a: i) cambios de comportamiento, control de biofilm supragingival, inflamación gingival y factores de riesgo; ii) instrumentación supragingival y subgingival, con y sin tratamientos coadyuvantes; iii) diferentes tipos de intervenciones quirúrgicas periodontales; y iv) el mantenimiento periodontal necesario para extender los beneficios a lo largo del tiempo. Conclusión: Esta Guía S3 informa a los clínicos, a los sistemas de salud, a los encargados de formular políticas sanitarias e, indirectamente, al público, sobre las modalidades disponibles y más eficaces para tratar la periodontitis y mantener una dentición sana durante toda la vida, de acuerdo con la evidencia disponible en el momento de su publicación.

In vitro evaluation of chemical decontamination of titanium discs.

Peri-implant diseases are caused by bacterial biofilm colonizing implant surfaces. Prevention and management of peri-implant mucositis and peri-implantitis rely on effective biofilm removal. This study aimed to evaluate biofilm removal and cytocompatibility following chemo-mechanical surface decontamination of biofilm-coated titanium discs. Biofilm-coated (Streptococcus gordonii) discs, with either non-modified (smooth) or modified (rough) surfaces, were instrumented using a sterile gauze soaked in one out of four solutions: saline (NaCl), alkaline electrized water (AEW), citric acid (CA) or N-acetyl-L-cysteine (NAC). Non-contaminated, untreated titanium discs served as controls (C). Residual deposits (bacteria and gauze fibers) and cytocompatibility for osteoblast-like cells were evaluated using SEM and immunofluorescence. Cytotoxicity was assessed using WST-8 assay and immunofluorescence. All protocols were equally effective in removing bacteria from smooth surfaces, while AEW and CA were found to be superior at rough surfaces. AEW and NAC were superior in promoting cytocompatibility over NaCl. NAC and CA had a strong cytotoxic effect on osteoblast-like and fibroblast cells. In conclusion, AEW may be beneficial in the decontamination of implant surfaces, effectively removing bacterial biofilm and restoring cytocompatibility.

Effect of biofilm formation on implant abutments with an anti-bacterial coating: A pre-clinical in vivo study.

OBJECTIVES: To analyse the long-term effect of plaque formation on implant abutments with an antibacterial coating and the ensuing host response in peri-implant tissues. MATERIALS AND METHODS: Four implants were installed in each mandibular premolar region following tooth extraction in six dogs. Three months later, two test abutments with a titanium-bismuth-gallium (Ti-Bi-Ga) coating and two control titanium abutments were connected to the implants on each side of the mandible. After 2 months, ligatures were placed around the implants in one side of the mandible and plaque formation was allowed until the end of the experiment. The ligatures were removed after 4 weeks. Radiographs and microbiological samples were obtained from each implant site during the plaque formation period. Biopsies were obtained 8 months after abutment connection and prepared for histological analysis. RESULTS: The analysis did not reveal any statistically significant differences in bone loss, bacterial growth and size of inflammatory lesions between implant units with and without the Ti-Bi-Ga coating. Implant sites exposed to the short period of ligature-induced breakdown demonstrated more pronounced bone loss and bacterial growth than non-ligature sites. CONCLUSIONS: It is suggested that a Ti-Bi-Ga coating does not prevent biofilm formation on the implant device and does not influence the ensuing host response in the adjacent peri-implant mucosa.

Risk for recurrence of disease following surgical therapy of peri-implantitis-A prospective longitudinal study.

OBJECTIVES: The aim of the present prospective study was to assess the risk for disease recurrence following surgical therapy of peri-implantitis. MATERIAL & METHODS: 73 patients (130 implants) treated surgically for peri-implantitis were examined at 1 and 5 years after therapy. The primary outcome was recurrence/progression of disease defined as any of the following events: (a) bone loss >1.0 mm, (b) surgical retreatment, (c) implant removal/loss after year 1. Patient- and implant-related parameters as well as 1-year outcomes were evaluated as potential predictors through multiple logistic regression analysis. RESULTS: 57 implants (44%) displayed recurrence/progression of peri-implantitis during follow-up. Among these, 27 implants were removed. Residual deep probing pocket depth (≥6 mm; odds ratio 7.4; 95% confidence interval 2.8-19.3) and reduced marginal bone level (OR 1.4; 95%CI 1.1-1.7) at 1 year after surgery constituted risk factors for recurrence/progression of disease. Furthermore, implants with modified surfaces were at higher risk than implants with non-modified surfaces (OR 5.1; 95%CI 1.6-16.5). CONCLUSION: Implants with (a) residual deep probing pocket depth, (b) reduced marginal bone level, or (c) modified surfaces following surgical therapy of peri-implantitis present with increased risk for recurrence/progression.

Cellular expression of DNA damage/repair and reactive oxygen/nitrogen species in human periodontitis and peri-implantitis lesions.

AIM OF THE STUDY: To evaluate differences in the cellular expression of DNA damage/repair and reactive oxygen/nitrogen species between human periodontitis and peri-implantitis lesions. MATERIAL AND METHODS: 40 patients presenting with generalized severe periodontitis and 40 patients with severe peri-implantitis were included. Soft tissue biopsies were collected from diseased sites in conjunction with surgical therapy and prepared for histological analysis. Four regions of interest were identified: the pocket epithelium (PE), the infiltrated connective tissue (ICT), which was divided into one inner area facing the PE (ICT-1) and one outer area (ICT-2). A non-infiltrated connective tissue area (NCT) lateral of the ICT was also selected. RESULTS: It was demonstrated that the ICT of peri-implantitis specimens was considerably larger and contained significantly larger area proportions and densities of CD68-, MPO- and iNOS-positive cells than that of periodontitis samples. Cellular densities were overall higher in the inner ICT zone lateral of the PE (ICT-1) than in the outer ICT compartment (ICT-2). While the NCT area lateral of the ICT comprised significantly larger proportions and densities of y-H2AX-, iNOS-, NOX2-, MPO- and PAD4/MPO-positive cells in peri-implantitis than in periodontitis sites, a reverse difference was noted for the area proportion and density of 8-OHdG-positive cells in the PE. CONCLUSIONS: It is suggested that peri-implantitis lesions are associated with an enhanced and upregulated host response and contain larger numbers of neutrophils, macrophages and iNOS-positive cells than periodontitis lesions.

Periodontitis lesions in smokers and non-smokers.

Differences in the progression of periodontitis have been observed between smokers and non-smokers. The aim of the present study was to compare vascular and inflammatory cell densities in periodontitis lesions from smokers and non-smokers to gain further understanding of the influence of smoking on histopathological characteristics of the disease. Two groups of patients with generalized severe periodontitis were recruited. One group consisted of 25 current smokers, aged 33-69 yr, while the second group comprised 21 non-smokers, aged 35-76 yr. From each patient, gingival biopsies were harvested from one periodontitis site (probing pocket depth ≥6 mm and bleeding on probing) and one site without clinical signs of gingival inflammation (reference site). Immunohistochemical analyses were performed to assess the density of vessels and inflammatory cells. Small differences existed between smokers and non-smokers regarding the size, proportion, number, and density of cells in periodontitis lesions. However, the vascular density in periodontitis lesions was significantly higher in non-smokers than in smokers. In clinically healthy reference sites, lesions were considerably smaller than in periodontitis sites and presented with similar vascular densities in smokers and non-smokers.

Characterization of macrophage polarization in periodontal disease.

AIM: To explore the M1/M2 status of macrophage polarization from healthy, gingivitis, and periodontitis patient samples. MATERIALS AND METHODS: Gingival biopsies were collected from 42 individuals (14 gingivitis, 18 periodontitis, and 10 healthy samples) receiving periodontal therapy. Histomorphology analysis was performed with haematoxylin and eosin staining. Immunofluorescence was performed using a combination of CD68 (macrophages), iNOS (M1), and CD206 (M2) in order to acquire changes in macrophage polarization at a single-cell resolution. Macrophages were quantified under microscopy using narrow wavelength filters to detect Alexa 488, Alexa 568, Alexa 633 fluorophores, and Hoechst 33342 to identify cellular DNA content. RESULTS: Gingivitis and periodontitis samples showed higher levels of macrophages compared with healthy samples. Unexpectedly, periodontitis samples displayed lower levels of macrophages dispersed in the stromal tissues compared with gingivitis samples; however, it remained higher than healthy tissues. The polarization of macrophages appears to be reduced in periodontitis and showed similar levels to those observed in healthy tissues. CONCLUSIONS: Our study found that gingivitis and periodontitis differ from each other by the levels of macrophage infiltrate, but not by changes in macrophage polarization.

Re-osseointegration following reconstructive surgical therapy of experimental peri-implantitis. A pre-clinical in vivo study.

OBJECTIVE: To evaluate the effect of bone substitute materials on hard and soft tissue healing in reconstructive surgical therapy of experimental peri-implantitis at implants with different surface characteristics. MATERIAL AND METHODS: Six female, Labrador dogs were used. 3 months after tooth extraction, four implants with two different surface characteristics (A and B) were installed on each side of the mandible. Experimental peri-implantitis was induced 3 months later. During surgical treatment of peri-implantitis, the implants were cleaned with curettes and cotton pellets soaked in saline. The implant sites were allocated to one of four treatment categories; (a) Group C; no augmentation, (b) Group T1; bone defect filled with deproteinized bovine bone mineral (c) Group T2; bone defect filled with a biphasic bone graft material, (d) Group T3; bone defect filled as T1 and covered with a collagen membrane. Clinical and radiological examinations were performed, and biopsies were obtained and prepared for histological analysis 6 months after peri-implantitis surgery. RESULTS: Implant B (smooth surface) sites showed significantly (a) larger radiographic bone level gain, (b) enhanced resolution of peri-implantitis lesions, and (c) larger frequency of re-osseointegration than implant A (moderately rough surface) sites. Implant B sites also showed superior preservation of the mucosal margin. Differences between bone substitute materials and control procedures were overall small with limited advantages for T1 and T2 sites. CONCLUSION: Healing following reconstructive surgical treatment of experimental peri-implantitis was superior around implants with a smooth surface than implants with a moderately rough surface. Benefits of using bone substitute materials during surgical therapy were overall small.

Peri-implantitis and its prevention.

This perspective article on peri-implantitis and its prevention was produced as a supplement to a 3-D, computer-animated film aiming at presenting key characteristics of peri-implant health, the build-up of a biofilm and the ensuing host-response resulting in peri-implant mucositis and, subsequently, peri-implantitis. Treatment concepts for peri-implantitis were briefly reviewed, and prevention of the condition was brought to attention as a priority in implant dentistry. The overview also highlighted the 2017 World Workshop on Classification of Periodontal and Peri-implant diseases and Conditions, in which new disease definitions and case definitions were presented for peri-implant health, peri-implant mucositis, and peri-implantitis.

Interleukin-17-producing T cells and interleukin-17 mRNA expression in periodontitis and long-standing gingivitis lesions.

BACKGROUND: T helper17 cells (Th17) are key targets in the evaluation of differences between "destructive" and "non-destructive" periodontal lesions. The aim of the present study was to analyze the density of interleukin-17 (IL-17) producing T cells and IL-17 mRNA expression in lesions representing severe periodontitis and longstanding gingivitis. METHODS: Two groups of patients were recruited. The gingivitis group consisted of 28 patients, 41-70 years old, with evident signs of gingival inflammation but no attachment loss. The periodontitis group consisted of 36 patients, 33-67 years of age. A gingival biopsy was obtained from one selected diseased site from each patient and prepared for immunohistochemical and reverse transcription, quantitative polymerase chain reaction (RT-qPCR) analysis. RESULTS: Although the density of CD3 positive cells (T cells) did not differ between the two types of lesions, the total number and density of cells positive for CD3+CD161 (IL-17-producing T-cells) were larger in periodontitis than in long-standing gingivitis lesions. About 30% of CD3-cells in periodontitis lesions were also positive for CD161. The corresponding figure for gingivitis samples was 15%. Analysis of covariance (ANCOVA) analysis revealed that differences between periodontitis and gingivitis samples remained after adjusting for smoking, age, and gender. In addition, males had larger proportions of IL-17 producing T cells than females in both groups. The IL-17 mRNA expression was higher in periodontitis than in gingivitis samples. CONCLUSION: It is suggested that IL-17 producing T cells represent a significant feature in the detection of differences between destructive and non-destructive lesions.

A new classification scheme for periodontal and peri-implant diseases and conditions - Introduction and key changes from the 1999 classification.

A classification scheme for periodontal and peri-implant diseases and conditions is necessary for clinicians to properly diagnose and treat patients as well as for scientists to investigate etiology, pathogenesis, natural history, and treatment of the diseases and conditions. This paper summarizes the proceedings of the World Workshop on the Classification of Periodontal and Peri-implant Diseases and Conditions. The workshop was co-sponsored by the American Academy of Periodontology (AAP) and the European Federation of Periodontology (EFP) and included expert participants from all over the world. Planning for the conference, which was held in Chicago on November 9 to 11, 2017, began in early 2015. An organizing committee from the AAP and EFP commissioned 19 review papers and four consensus reports covering relevant areas in periodontology and implant dentistry. The authors were charged with updating the 1999 classification of periodontal diseases and conditions and developing a similar scheme for peri-implant diseases and conditions. Reviewers and workgroups were also asked to establish pertinent case definitions and to provide diagnostic criteria to aid clinicians in the use of the new classification. All findings and recommendations of the workshop were agreed to by consensus. This introductory paper presents an overview for the new classification of periodontal and peri-implant diseases and conditions, along with a condensed scheme for each of four workgroup sections, but readers are directed to the pertinent consensus reports and review papers for a thorough discussion of the rationale, criteria, and interpretation of the proposed classification. Changes to the 1999 classification are highlighted and discussed. Although the intent of the workshop was to base classification on the strongest available scientific evidence, lower level evidence and expert opinion were inevitably used whenever sufficient research data were unavailable. The scope of this workshop was to align and update the classification scheme to the current understanding of periodontal and peri-implant diseases and conditions. This introductory overview presents the schematic tables for the new classification of periodontal and peri-implant diseases and conditions and briefly highlights changes made to the 1999 classification. It cannot present the wealth of information included in the reviews, case definition papers, and consensus reports that has guided the development of the new classification, and reference to the consensus and case definition papers is necessary to provide a thorough understanding of its use for either case management or scientific investigation. Therefore, it is strongly recommended that the reader use this overview as an introduction to these subjects. Accessing this publication online will allow the reader to use the links in this overview and the tables to view the source papers (Table ).