Microbiological dynamics of red complex bacteria following full-mouth air polishing in periodontally healthy subjects-a randomized clinical pilot study.

OBJECTIVES: Suppression of periodontal pathogens in the oral cavity of periodontally healthy individuals may lower the risk for periodontal or periimplant diseases. Therefore, the present study aimed to analyze the effect of supragingival debridement (SD) with adjunctive full mouth glycine powder air polishing (FM-GPAP) on the prevalence of periodontal pathogens in periodontally healthy individuals. MATERIALS AND METHODS: Eighty-seven systemically and periodontally healthy intraoral carriers of red complex bacteria, i.e., Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola or other periodontal pathogens including Aggregatibacter actinomycetemcomitans, Prevotella intermedia, and Eikenella corrodens were enrolled into the study and randomly assigned to receive SD with adjunctive FM-GPAP (test, n = 42) or SD alone (control, n = 45). In the first observation period, microbiological samples were obtained prior to, and 2, 5, and 9 days following intervention. If one of these periodontal pathogens could still not be identified, additional microbial sampling was performed after 6 and 12 weeks. RESULTS: The prevalence of red complex bacteria was significantly reduced in the test compared to the control group following treatment (p = 0.004) and at day 9 (p = 0.031). Intragroup comparison showed a significant (test, p < 0.001; control, p ≤ 0.01) reduction in the mean prevalence in both groups from BL through day 9 with an additional significant intergroup difference (p = 0.048) at day 9. However, the initial strong reduction returned to baseline values after 6 and 12 weeks. CONCLUSION: In periodontally healthy carriers of periodontal pathogens, FM-GPAP as an adjunct to SD transiently enhances the suppression of red complex bacteria. CLINICAL RELEVANCE: Whether the enhanced suppression of red complex bacteria by adjunctive FM-GPAP prevents the development of periodontitis in periodontally healthy carriers requires further investigations.

Periodontitis: Consensus report of workgroup 2 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions.

A new periodontitis classification scheme has been adopted, in which forms of the disease previously recognized as "chronic" or "aggressive" are now grouped under a single category ("periodontitis") and are further characterized based on a multi-dimensional staging and grading system. Staging is largely dependent upon the severity of disease at presentation as well as on the complexity of disease management, while grading provides supplemental information about biological features of the disease including a history-based analysis of the rate of periodontitis progression; assessment of the risk for further progression; analysis of possible poor outcomes of treatment; and assessment of the risk that the disease or its treatment may negatively affect the general health of the patient. Necrotizing periodontal diseases, whose characteristic clinical phenotype includes typical features (papilla necrosis, bleeding, and pain) and are associated with host immune response impairments, remain a distinct periodontitis category. Endodontic-periodontal lesions, defined by a pathological communication between the pulpal and periodontal tissues at a given tooth, occur in either an acute or a chronic form, and are classified according to signs and symptoms that have direct impact on their prognosis and treatment. Periodontal abscesses are defined as acute lesions characterized by localized accumulation of pus within the gingival wall of the periodontal pocket/sulcus, rapid tissue destruction and are associated with risk for systemic dissemination.

Periodontitis: Consensus report of workgroup 2 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions.

A new periodontitis classification scheme has been adopted, in which forms of the disease previously recognized as "chronic" or "aggressive" are now grouped under a single category ("periodontitis") and are further characterized based on a multi-dimensional staging and grading system. Staging is largely dependent upon the severity of disease at presentation as well as on the complexity of disease management, while grading provides supplemental information about biological features of the disease including a history-based analysis of the rate of periodontitis progression; assessment of the risk for further progression; analysis of possible poor outcomes of treatment; and assessment of the risk that the disease or its treatment may negatively affect the general health of the patient. Necrotizing periodontal diseases, whose characteristic clinical phenotype includes typical features (papilla necrosis, bleeding, and pain) and are associated with host immune response impairments, remain a distinct periodontitis category. Endodontic-periodontal lesions, defined by a pathological communication between the pulpal and periodontal tissues at a given tooth, occur in either an acute or a chronic form, and are classified according to signs and symptoms that have direct impact on their prognosis and treatment. Periodontal abscesses are defined as acute lesions characterized by localized accumulation of pus within the gingival wall of the periodontal pocket/sulcus, rapid tissue destruction and are associated with risk for systemic dissemination.

Consensus Conference Findings on Supragingival and Subgingival Air Polishing.

A consensus conference was convened to evaluate and address issues of safety and efficacy when using glycine powder in an air-powder jet device for supra- and subgingival applications during dental prophylaxis and periodontal maintenance. The conference reported the following conclusions: 1) Supra- and subgingival air polishing using glycine powder is safe and effective for removal of biofilms from natural tooth structure and restorative materials; 2) there is no evidence of soft-tissue abrasion when using glycine powder in an air-polishing device; 3) in periodontal probing depths of 1 mm to 4 mm, glycine-powder air polishing, using a standard air-polishing nozzle, is more effective at removing subgingival biofilm than manual or ultrasonic instruments; and 4) at probing depths of 5 mm to 9 mm, using a subgingival nozzle, glycine powder air polishing is more effective at removing subgingival biofilm than manual or ultrasonic instrumentation. This conference statement, supported by an industry grant, was drafted by a panel of distinguished dental professionals.

Towards microbiome transplant as a therapy for periodontitis: an exploratory study of periodontitis microbial signature contrasted by oral health, caries and edentulism.

BACKGROUND: Conventional periodontal therapy aims at controlling supra- and subgingival biofilms. Although periodontal therapy was shown to improve periodontal health, it does not completely arrest the disease. Almost all subjects compliant with periodontal maintenance continue to experience progressive clinical attachment loss and a fraction of them loses teeth. An oral microbial transplant may be a new alternative for treating periodontitis (inspired by fecal transplant). First, it must be established that microbiomes of oral health and periodontitis are distinct. In that case, the health-associated microbiome could be introduced into the oral cavity of periodontitis patients. This relates to the goals of our study: (i) to assess if microbial communities of the entire oral cavity of subjects with periodontitis were different from or oral health contrasted by microbiotas of caries and edentulism patients; (ii) to test in vitro if safe concentration of sodium hypochlorite could be used for initial eradication of the original oral microbiota followed by a safe neutralization of the hypochlorite prior transplantation. METHODS: Sixteen systemically healthy white adults with clinical signs of one of the following oral conditions were enrolled: periodontitis, established caries, edentulism, and oral health. Oral biofilm samples were collected from sub- and supra-gingival sites, and oral mucosae. DNA was extracted and 16S rRNA genes were amplified. Amplicons from the same patient were pooled, sequenced and quantified. Volunteer's oral plaque was treated with saline, 16 mM NaOCl and NaOCl neutralized by ascorbate buffer followed by plating on blood agar. RESULTS: Ordination plots of rRNA gene abundances revealed distinct groupings for the oral microbiomes of subjects with periodontitis, edentulism, or oral health. The oral microbiome in subjects with periodontitis showed the greatest diversity harboring 29 bacterial species at significantly higher abundance compared to subjects with the other assessed conditions. Healthy subjects had significantly higher abundance in 10 microbial species compared to the other conditions. NaOCl showed strong antimicrobial properties; nontoxic ascorbate was capable of neutralizing the hypochlorite. CONCLUSIONS: Distinct oral microbial signatures were found in subjects with periodontitis, edentulism, or oral health. This finding opens up a potential for a new therapy, whereby a health-related entire oral microbial community would be transplanted to the diseased patient.

Interruption of Electrical Conductivity of Titanium Dental Implants Suggests a Path Towards Elimination Of Corrosion.

Peri-implantitis is an inflammatory disease that results in the destruction of soft tissue and bone around the implant. Titanium implant corrosion has been attributed to the implant failure and cytotoxic effects to the alveolar bone. We have documented the extent of titanium release into surrounding plaque in patients with and without peri-implantitis. An in vitro model was designed to represent the actual environment of an implant in a patient's mouth. The model uses actual oral microbiota from a volunteer, allows monitoring electrochemical processes generated by biofilms growing on implants and permits control of biocorrosion electrical current. As determined by next generation DNA sequencing, microbial compositions in experiments with the in vitro model were comparable with the compositions found in patients with implants. It was determined that the electrical conductivity of titanium implants was the key factor responsible for the biocorrosion process. The interruption of the biocorrosion current resulted in a 4-5 fold reduction of corrosion. We propose a new design of dental implant that combines titanium in zero oxidation state for osseointegration and strength, interlaid with a nonconductive ceramic. In addition, we propose electrotherapy for manipulation of microbial biofilms and to induce bone healing in peri-implantitis patients.

EAO consensus conference: economic evaluation of implant-supported prostheses.

OBJECTIVE: There are various alternatives for the management of oral conditions that may lead to or already have lead to partial or full edentulism. Economic evaluations measure the efficiency of alternative healthcare interventions and provide useful information for decision-making and the allocation of scarce resources. MATERIAL AND METHODS: The current English literature dealing with "cost-effectiveness" of dental implant therapy versus different alternative treatment modalities, that is, complete and fixed partial dentures, root canal, and periodontal treatment, has been included in this narrative review. Due to the high heterogeneity within the literature, a meta-analysis could not be conducted. RESULTS: The available evidence from economic evaluations indicated that for the treatment of central incisors with irreversible pulpitis and coronal lesions, root canal treatments were most cost-effective initial treatment options. When initial root canal treatments failed, orthograde retreatments were most cost-effective. When root canal retreatments failed, extractions and replacement with single implant-supported crowns were more cost-effective compared to fixed or removable partial dentures. In the treatment of periodontitis in molars with Class I furcation invasion, non-surgical periodontal therapy was more effective and costed less than implant-supported single crowns. For the replacement of single missing teeth, two evaluations indicated that implant-supported single crowns provided better outcomes in terms of greater quality-adjusted tooth years or survival rates at lower costs compared to fixed partial prostheses. Another economic evaluation found that implant-supported crowns costed more, but provided greater survival rates compared to fixed partial dentures. For the restoration of edentulous mandibles, two evaluations indicated that overdentures retained by two or four implants improved oral health-related quality of life outcomes, but costed more than complete dentures. CONCLUSIONS: To better assess the efficiency of implant-supported prostheses in various clinical conditions, more economic evaluations are needed that follow well-established methodologies in health economics.

Periodontitis associated with plasminogen deficiency: a case report.

BACKGROUND: Plasminogen deficiency is a rare autosomal recessive disease, which is associated with aggressive periodontitis and gingival enlargement. Previously described treatments of plasminogen deficiency associated periodontitis have shown limited success. This is the first case report indicating a successful therapy approach consisting of a non-surgical supra- and subgingival debridement in combination with an adjunctive systemic antibiotic therapy and a strict supportive periodontal regimen over an observation period of 4 years. CASE PRESENTATION: The intraoral examination of a 17-year-old Turkish female with severe plasminogen deficiency revealed generalized increased pocket probing depths ranging from 6 to 9 mm, bleeding on probing over 30%, generalized tooth mobility, and gingival hyperplasia. Alveolar bone loss ranged from 30% to 50%. Clinical attachment loss corresponded to pocket probing depths. Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Treponema denticola, Prevotella intermedia, Prevotella nigrescens and Eikenella corrodens have been detected by realtime polymerase chain reaction. Periodontal treatment consisted of full mouth disinfection and adjunctive systemic administration of amoxicillin (500 mg tid) and metronidazole (400 mg tid). A strict supportive periodontal therapy regimen every three month in terms of supra- and subgingival debridement was rendered. The reported therapy has significantly improved periodontal health and arrested disease progression. Intraoral examination at the end of the observation period 3.5 years after non-surgical periodontal therapy showed generalized decreased pocket probing depths ranging from 1 to 6 mm, bleeding on probing lower 30%, and tooth mobility class I and II. Furthermore, microbiological analysis shows the absence of Porphyromonas gingivalis, Prevotella intermedia and Treponema denticola after therapy. CONCLUSION: Adjunctive antibiotic treatment may alter the oral microbiome and thus, the inflammatory response of periodontal disease associated to plasminogen deficiency and diminishes the risk of pseudomembrane formation and progressive attachment loss. This case report indicates that patients with plasminogen deficiency may benefit from non-surgical periodontal treatment in combination with an adjunctive antibiotic therapy and a strict supportive periodontal therapy regimen.

Economics of periodontal care: market trends, competitive forces and incentives.

The adoption of new technologies for the treatment of periodontitis and the replacement of teeth has changed the delivery of periodontal care. The objective of this review was to conduct an economic analysis of a mature periodontal service market with a well-developed workforce, including general dentists, dental hygienists and periodontists. Publicly available information about the delivery of periodontal care in the USA was used. A strong trend toward increased utilization of nonsurgical therapy and decreased utilization of surgical periodontal therapy was observed. Although periodontal surgery remained the domain of periodontists, general dentists had taken over most of the nonsurgical periodontal care. The decline in surgical periodontal therapy was associated with an increased utilization of implant-supported prosthesis. Approximately equal numbers of implants were surgically placed by periodontists, oral and maxillofacial surgeons, and general dentists. Porter's framework of the forces driving industry competition was used to analyze the role of patients, dental insurances, general dentists, competitors, entrants, substitutes and suppliers in the periodontal service market. Estimates of out-of-pocket payments of self-pay and insured patients, reimbursement by dental insurances and providers' earnings for various periodontal procedures and alternative treatments were calculated. Economic incentives for providers may explain some of the observed shifts in the periodontal service market. Given the inherent uncertainty about treatment outcomes in dentistry, which makes clinical judgment critical, providers may yield to economic incentives without jeopardizing their ethical standards and professional norms. Although the economic analysis pertains to the USA, some considerations may also apply to other periodontal service markets.

A paradigm shift in mechanical biofilm management? Subgingival air polishing: a new way to improve mechanical biofilm management in the dental practice.

In the past few years indications for the use of the air polishing technology have been expanded from supragingival use (airflow) to subgingival air polishing (perioflow) by the development of new low-abrasive glycine-based powders and devices with a subgingival nozzle. Several studies on the subgingival use of air polishing have been completed. On 7 June 2012, during the Europerio 7 Congress in Vienna, a consensus conference on mechanical biofilm management took place aiming to review the current evidence from the literature on the clinical relevance of the subgingival use of air polishing and to make practical recommendations for the clinician. Bernita Bush (Bern), Prof Johannes Einwag (Stuttgart), Prof Thomas Flemmig (Seattle), Carmen Lanoway (Munich), Prof Ursula Platzer (Hamburg), Prof Petra Schmage (Hamburg), Brigitte Schoeneich (Zurich), Prof Anton Sculean (Bern), Dr Clemens Walter (Basel), and Prof Jan Wennström (Gothenburg) discussed under the moderation of Klaus-Dieter Bastendorf and Christian Becker (both ADIC Association for Dental Infection Control) the available clinical studies to reach a consensus on available clinical evidence. This paper summarizes the main conclusions of the consensus conference and points to the clinical relevance of the findings for the dental practitioner.

Non-surgical therapy for the management of peri-implantitis: a systematic review.

UNLABELLED: Peri-implantitis is characterized by mucosal inflammation and loss of supporting peri-implant bone. OBJECTIVE: The objective of this systematic review was to evaluate the efficacy and safety of non-surgical treatment of peri-implantitis. MATERIALS AND METHODS: MEDLINE, Embase, and Web of Science were searched to identify randomized clinical trial studies that assessed non-surgical treatment of peri-implantitis with a minimum follow-up period of 3 months. RESULTS: From a total of 29 abstracts, nine trials were included in this systematic review. Adjunctive local delivery of antibiotics, submucosal glycine powder air polishing, or Er:YAG laser treatment resulted in greater reduction in bleeding on probing compared with submucosal debridement using curettes with adjunctive irrigation with chlorhexidine. In addition, greater reductions in probing depths were found following adjunctive local delivery of antibiotics. The evidence neither supported nor refuted the clinical efficacy of submucosal debridement using curettes or ultrasonic scalers alone. No progressive bone loss was found following any of the assessed treatments over a maximum observation period of 12 months. Only two studies reported implant survival rates, which were 100% over 6 months. CONCLUSIONS: The available evidence suggested that submucosal debridement with adjunctive local delivery of antibiotics, submucosal glycine powder air polishing, or Er:YAG laser treatment may reduce clinical signs of peri-implant mucosal inflammation to a greater extent relative to submucosal debridement using curettes with adjunctive irrigation with chlorhexidine. Long-term randomized controlled trials are needed to assess the efficacy of non-surgical therapy on progressing bone loss, implant survival rates, and measures of oral health-related quality of life.

Randomized controlled trial assessing efficacy and safety of glycine powder air polishing in moderate-to-deep periodontal pockets.

BACKGROUND: Supragingivally applied glycine powder air polishing (SupraGPAP) has been shown to remove biofilms in shallow periodontal pockets. This study assesses efficacy and safety of subgingivally applied glycine powder air polishing (SubGPAP) in moderate-to-deep periodontal pockets. METHODS: Patients with chronic periodontitis and intraoral Porphyromonas gingivalis (P. gingivalis) and Tannerella forsythia who completed initial therapy were randomly assigned to receive SubGPAP in periodontal pockets with probing depths of 4 to 9 mm, SupraGPAP in all other shallow periodontal sites, and at mucous membranes followed by removal of calculus using curets (full-mouth GPAP) or scaling and root planing followed by coronal polishing (SRP). Patients rinsed with 0.12% chlorhexidine gluconate after debridement, and twice daily, for 2 weeks. RESULTS: All 30 patients enrolled completed the baseline, day 10, and day 90 visits. SubGPAP resulted in significantly lower total viable bacterial counts in moderate-to-deep pockets when compared to SRP immediately after debridement and at day 10 (P <0.05). Total P. gingivalis counts in the oral cavity were significantly reduced after full-mouth GPAP compared to SRP at day 90 (P <0.05). Patients' comfort levels were high for both treatments. There were no adverse events related to full-mouth GPAP. CONCLUSIONS: The results indicate that SubGPAP is more efficacious in removing subgingival biofilm in moderate-to-deep periodontal pockets than SRP. Furthermore, full-mouth GPAP may result in a beneficial shift of the oral microbiota and appears to be well tolerated.

Efficacy and safety of adjunctive local moxifloxacin delivery in the treatment of periodontitis.

BACKGROUND: Moxifloxacin exerts excellent antibacterial activity against most putative periodontal pathogens and has been shown to kill bacteria in biofilm and host cells. METHODS: Patients with chronic periodontitis were randomly assigned to receive a single subgingival application of a 0.125%, 0.4%, or 1.25% moxifloxacin gel or placebo gel immediately after full-mouth scaling and root planing (SRP). Clinical efficacy measurements were assessed in sites with baseline probing depth (PD) of ≥5.4 mm at 6 weeks and 3 months and any adverse events were determined. In addition, putative periodontal pathogens and resistance of subgingival bacteria against moxifloxacin were assessed. RESULTS: Data of 57 patients were included in the statistical analysis. In all treatment groups, the PD decreased from baseline to 3 months, with the greatest reduction seen in patients treated with moxifloxacin 0.4% (1.5 ± 0.6 mm; P = 0.023 compared to placebo), followed by patients receiving moxifloxacin 1.25% (1.2 ± 0.4), moxifloxacin 0.125% (1.1 ± 1.1), and placebo (1.0 ± 0.6). No linear trend for PD reduction with increasing moxifloxacin concentrations was found. Porphyromonas gingivalis showed the greatest reduction in prevalence among the assessed pathogens, without any significant intergroup differences. No correlation or systematic relationship between adverse events, including bacterial resistance against moxifloxacin, and the investigational gels was found. CONCLUSIONS: In periodontal pockets with PD of ≥5.4 mm, a single subgingival administration of a 0.4% moxifloxacin gel as an adjunct to SRP may result in additional PD reduction compared to SRP alone. In addition, the investigated moxifloxacin gels seem to be safe.

Tissue augmentation and esthetics (Working Group 3).

INTRODUCTION: The remit of this working group was to update the existing knowledge base regarding bone augmentation for implant site development and soft-tissue grafting for esthetic outcomes. Four reviews from the working group formed the basis of this update. Moreover, clinical applications as well as suggestions for further research have been formulated. MATERIALS AND METHODS: The papers in the working group critically reviewed the literature. Four manuscripts were produced assessing (a) the outcomes of correcting dehiscence and fenestration defects at implant sites using various graft materials, (b) the outcomes of sinus floor augmentation at maxillary posterior sites with 6 mm or less residual bone height using various graft materials, (c) the association of the horizontal dimensions of buccal and interproximal bone with esthetic outcomes of implant-supported restorations, and (d) the outcomes of soft-tissue augmentations. RESULTS: The results and conclusions of the review process are presented in the following papers. The group's consensus statements, clinical implications, and directions for future research are presented in this article.

Role of fibroblast populations in peri-implantitis.

PURPOSE: To understand the contribution of stromal cells, such as granulation tissue fibroblasts, to peri-implantitis with regard to (1) the secretion of constitutive factors promoting migration/survival of infiltrates into osseointegrated sites; and (2) the effect of exogenous infiltrate cytokines on the cells' secretion. MATERIALS AND METHODS: Fibroblasts were cultured from eight peri-implantitis sites. Multiplexed enzyme-linked immunosorbent assay was used to quantify factors secreted by the cells either unstimulated or stimulated with gamma interferon (IFN gamma), interleukin 4 (IL4), or tumor necrosis factor alpha (TNF alpha). Controls consisted of fibroblasts cultured from healthy gingival and chronic periodontitis granulation tissues. RESULTS: Peri-implantitis fibroblasts differed significantly from periodontitis fibroblasts in their reduced secretion of the collagen inducer transforming growth factor beta-1 (TGF beta 1) and tissue inhibitor of metalloproteinase-1. The cells exhibited enhanced secretion of angiogenic factor vascular endothelial growth factor (VEGF) and collagenolytic matrix metalloproteinase 1 (MMP1) compared to both healthy and periodontitis fibroblasts. Fibroblasts from both periodontitis and peri-implantitis sites exhibited a pronounced proinflammatory profile compared to normal gingival fibroblasts with respect to secretion of chemokines IL6, IL8, and monocyte chemoattractant protein 1 (MCP1). Fibroblasts stimulated with TNF alpha showed increased levels of IL6, IL8, MCP1; neutrophil chemokine growth-related oncogene alpha stimulation with IFN gamma increased MCP1; and stimulation with IL4 increased VEGF. CONCLUSION: The results indicate that peri-implantitis fibroblasts represent a distinct stromal population. The cells might participate in the pathogenesis of peri-implantitis by up-regulating both vascularity and matrix breakdown, thus promoting migration/maintenance of infiltrates into the site. Cytokines produced by infiltrates could enhance the inflammatory nature of the cells in a self-feeding loop.

Are putative periodontal pathogens reliable diagnostic markers?

Periodontitis is one of the most common chronic inflammatory diseases. A number of putative bacterial pathogens have been associated with the disease and are used as diagnostic markers. In the present study, we compared the prevalence of oral bacterial species in the subgingival biofilm of generalized aggressive periodontitis (GAP) (n = 44) and chronic periodontitis (CP) (n = 46) patients with that of a periodontitis-resistant control group (PR) (n = 21). The control group consisted of subjects at least 65 years of age with only minimal or no periodontitis and no history of periodontal treatment. A total of 555 samples from 111 subjects were included in this study. The samples were analyzed by PCR of 16S rRNA gene fragments and subsequent dot blot hybridization using oligonucleotide probes specific for Aggregatibacter (Actinobacillus) actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, a Treponema denticola-like phylogroup (Treponema phylogroup II), Treponema lecithinolyticum, Campylobacter rectus, Fusobacterium spp., and Fusobacterium nucleatum, as well as Capnocytophaga ochracea. Our data confirm a high prevalence of the putative periodontal pathogens P. gingivalis, P. intermedia, and T. forsythia in the periodontitis groups. However, these species were also frequently detected in the PR group. For most of the species tested, the prevalence was more associated with increased probing depth than with the subject group. T. lecithinolyticum was the only periodontopathogenic species showing significant differences both between GAP and CP patients and between GAP patients and PR subjects. C. ochracea was associated with the PR subjects, regardless of the probing depth. These results indicate that T. lecithinolyticum may be a diagnostic marker for GAP and C. ochracea for periodontal health. They also suggest that current presumptions of the association of specific bacteria with periodontal health and disease require further evaluation.

Gene expression in periodontal tissues following treatment.

BACKGROUND: In periodontitis, treatment aimed at controlling the periodontal biofilm infection results in a resolution of the clinical and histological signs of inflammation. Although the cell types found in periodontal tissues following treatment have been well described, information on gene expression is limited to few candidate genes. Therefore, the aim of the study was to determine the expression profiles of immune and inflammatory genes in periodontal tissues from sites with severe chronic periodontitis following periodontal therapy in order to identify genes involved in tissue homeostasis.Gingival biopsies from 12 patients with severe chronic periodontitis were taken six to eight weeks following non-surgical periodontal therapy, and from 11 healthy controls. As internal standard, RNA of an immortalized human keratinocyte line (HaCaT) was used. Total RNA was subjected to gene expression profiling using a commercially available microarray system focusing on inflammation-related genes. Post-hoc confirmation of selected genes was done by Realtime-PCR. RESULTS: Out of the 136 genes analyzed, the 5% most strongly expressed genes compared to healthy controls were Interleukin-12A (IL-12A), Versican (CSPG-2), Matrixmetalloproteinase-1 (MMP-1), Down syndrome critical region protein-1 (DSCR-1), Macrophage inflammatory protein-2beta (Cxcl-3), Inhibitor of apoptosis protein-1 (BIRC-1), Cluster of differentiation antigen 38 (CD38), Regulator of G-protein signalling-1 (RGS-1), and Finkel-Biskis-Jinkins murine osteosarcoma virus oncogene (C-FOS); the 5% least strongly expressed genes were Receptor-interacting Serine/Threonine Kinase-2 (RIP-2), Complement component 3 (C3), Prostaglandin-endoperoxide synthase-2 (COX-2), Interleukin-8 (IL-8), Endothelin-1 (EDN-1), Plasminogen activator inhibitor type-2 (PAI-2), Matrix-metalloproteinase-14 (MMP-14), and Interferon regulating factor-7 (IRF-7). CONCLUSION: Gene expression profiles found in periodontal tissues following therapy indicate activation of pathways that regulate tissue damage and repair.