The economic and societal impact of periodontal and peri-implant diseases.

Periodontal and peri-implant diseases result from a chronic inflammatory response to dysbiotic microbial communities and are characterized by inflammation in the soft tissue and the ensuing progressive destruction of supporting bone, resulting in tooth or implant loss. These diseases' high prevalence, multifactorial etiology, extensive treatment costs, and significant detriment to patients' quality-of-life underscore their status as a critical public health burden. This review delineates the economic and sociocultural ramifications of periodontal and peri-implant diseases on patient welfare and healthcare economics. We delve into the implications of diagnosis, treatment, supportive care, and managing destructive tissue consequences, contrasting these aspects with healthy patients.

Impact of smoking on cost-effectiveness of 10-48 years of periodontal care.

The study aims were (1) to explore whether "periodontal treatment" consisting of surgical therapy (flap, resective, or regenerative) or scaling and root planing treatment with long-term periodontal maintenance treatment, is cost-effective in terms of preventing periodontitis-attributable tooth extraction and replacement by implant-supported crowns ("extraction/replacement"); (2) to assess the effect of cigarette smoking on this cost-effectiveness. Data for this observational retrospective study were collected from dental charts of patients who had received periodontal therapy and at least annual follow-up visits for >10 years were analyzed by linear regression generalized estimating equations and generalized linear models. Among 399 adults (199 males, 200 females), those with the least mean annual treatment cost experienced the greatest mean annual costs for extraction/replacement, indicating general cost-effectiveness. Cigarette smoking adversely impacted this cost-effectiveness, with current heavy smokers experiencing no cost-effectiveness. Former smokers with Grade C periodontitis benefitted most, whereas smoking did not influence cost-effectiveness for Grade B periodontitis. Assessed by mean annual costs of "extraction/replacement," periodontal treatment was cost-effective, which decreased in a dose-response manner by former and current smoking intensity. Cigarette smoking should be factored into treatment planning and cost-effective analyses of periodontal treatment. Smoking cessation should be encouraged.

Performance of three artificial intelligence (AI)-based large language models in standardized testing; implications for AI-assisted dental education.

INTRODUCTION: The emerging rise in novel computer technologies and automated data analytics has the potential to change the course of dental education. In line with our long-term goal of harnessing the power of AI to augment didactic teaching, the objective of this study was to quantify and compare the accuracy of responses provided by ChatGPT (GPT-4 and GPT-3.5) and Google Gemini, the three primary large language models (LLMs), to human graduate students (control group) to the annual in-service examination questions posed by the American Academy of Periodontology (AAP). METHODS: Under a comparative cross-sectional study design, a corpus of 1312 questions from the annual in-service examination of AAP administered between 2020 and 2023 were presented to the LLMs. Their responses were analyzed using chi-square tests, and the performance was juxtaposed to the scores of periodontal residents from corresponding years, as the human control group. Additionally, two sub-analyses were performed: one on the performance of the LLMs on each section of the exam; and in answering the most difficult questions. RESULTS: ChatGPT-4 (total average: 79.57%) outperformed all human control groups as well as GPT-3.5 and Google Gemini in all exam years (p < .001). This chatbot showed an accuracy range between 78.80% and 80.98% across the various exam years. Gemini consistently recorded superior performance with scores of 70.65% (p = .01), 73.29% (p = .02), 75.73% (p < .01), and 72.18% (p = .0008) for the exams from 2020 to 2023 compared to ChatGPT-3.5, which achieved 62.5%, 68.24%, 69.83%, and 59.27% respectively. Google Gemini (72.86%) surpassed the average scores achieved by first- (63.48% ± 31.67) and second-year residents (66.25% ± 31.61) when all exam years combined. However, it could not surpass that of third-year residents (69.06% ± 30.45). CONCLUSIONS: Within the confines of this analysis, ChatGPT-4 exhibited a robust capability in answering AAP in-service exam questions in terms of accuracy and reliability while Gemini and ChatGPT-3.5 showed a weaker performance. These findings underscore the potential of deploying LLMs as an educational tool in periodontics and oral implantology domains. However, the current limitations of these models such as inability to effectively process image-based inquiries, the propensity for generating inconsistent responses to the same prompts, and achieving high (80% by GPT-4) but not absolute accuracy rates should be considered. An objective comparison of their capability versus their capacity is required to further develop this field of study.

Clinical, immunological and microbiological evaluation of experimental peri-implant mucositis and gingivitis in subjects with Grade C, stage III/IV periodontitis background.

AIM: To compare individuals with a periodontitis background (Grade C, stage III/IV-formerly generalized aggressive periodontitis) (H-GAP) with periodontally healthy subjects (H-Health) in terms of molecular changes (immunological/microbiological) accompanying experimental peri-implant mucositis and gingivitis. MATERIALS AND METHODS: H-GAP and control (H-Health) subjects were recruited, and experimental mucositis/gingivitis was induced around a single screw-retained implant and one contralateral tooth. Participants refrained from oral hygiene for 21 days in the selected areas, followed by professional prophylaxis and hygiene instructions for 21 days. Clinical parameters, immunological markers (multiplex analysis) and microbial data (16S rRNA gene sequencing) were collected at baseline, during induction (7, 14 and 21 days) and following remission (42 days). RESULTS: Clinically, no significant differences were observed between the groups (n = 10/each group) (H-GAP vs. H-Health) (p > .05, Mann-Whitney test) and the type of site (tooth vs. implant) (p > .05, Wilcoxon test) at the time of onset and resolution, or severity of gingival/mucosal inflammation. H-GAP displayed lower concentrations of the cytokines interleukin (IL)-1B, IL-4, IL-17, tumor necrosis factor-α and interferon-γ around implants than H-Health at baseline and during induction of mucositis (p < .05, Mann-Whitney test). In both groups, implants showed significantly higher inflammatory background at baseline and all subsequent visits when compared with teeth (p < .05, Wilcoxon test). Alpha and ß-diversity metrics showed a significant shift in the microbiome composition and abundances of core species during induction and resolution of peri-implant mucositis and gingivitis (p < .05, restricted maximum likelihood method of Shannon and Bray-Curtis indices, respectively). Differences were not significant for these parameters between the H-Health and H-GAP groups when the periodontal and peri-implant microbiomes were compared separately; however, at each time point, the peri-implant microbiome differed significantly from the periodontal microbiome. CONCLUSIONS: Within the limitations of this pilot study (e.g. low power), it can be concluded that different microbial shifts contribute to the onset and progression of inflammatory responses around teeth and implants and that history of periodontal disease experience plays an additional role in modulating the immune response of peri-implant and periodontal tissues to biofilm accumulation.

Residual vertical defects: risk of disease progression, retreatment rates, and cost: a retrospective analysis.

OBJECTIVES: This study aimed to explore the relationship between Radiographic Residual Vertical Defects (RVDs) and the progression of periodontitis in patients undergoing periodontal maintenance therapy (PMT). MATERIALS AND METHODS: Teeth with RVDs were compared to the same contralateral teeth in the same patient. The study investigated the effect of smoking, diabetes, compliance, disease Stage, and Grade, baseline probing depth (PD), periodontal risk score (PRS), baseline pocket closure (PC) (≤ 4 mm), and tooth mobility on disease progression. We calculated the need for retreatment during PMT and its associated cost. Generalized estimation equations and linear and multilevel logistic regression analyses were employed for data analysis. RESULTS: Each group had 139 teeth, accounting for 80 patients. Although the group with RVDs had similar PD reduction compared to the control teeth, the prevalence of PC at the last follow-up was reduced to half in the RVDs group (odds ratio OR = 0.5; p-value = 0.028), regardless of PC status at the baseline. RVDs were also significant predictors of tooth loss due to periodontitis (TLP), with an OR of 2.28 (p = 0.043). Patients with diabetes, Stage IV, higher mobility, and higher PRS scores had a higher risk of tooth loss due to periodontitis (OR = 4.71, 3.84, 3.64, and 5.97, respectively (P < 0.01). Incidences of sites requiring retreatment were similar in both groups, but the cost of treatment was 30% higher for teeth with RVDs. Grade C had the most significant influence on receiving retreatments (OR = 18.8, p = 0.005). CONCLUSION: Teeth with RVDs represent a risk indicator for tooth loss compared to identical contralateral teeth with similar PD in the same patient. Teeth with RVD had more risk of pocket opening during follow-up. CLINICAL RELEVANCE: While teeth with RVDs can be maintained long-term, they have twice the risk of pocket opening and tooth loss due to periodontitis during follow-up. Patients with systemic and local risk factors need to be monitored closely as they are at the highest risk of losing teeth with RVDs. The increased cost of retreatment for teeth with RVDs also has implications in terms of retention versus extraction and replacement.

Histological assessment and gene expression analysis of intra-oral soft tissue graft donor sites.

AIM: To determine the structural and gene expression features of different intra-oral soft tissue donor sites (i.e., anterior palate, posterior palate, maxillary tuberosity and retromolar pad). MATERIALS AND METHODS: Standardized mucosal tissue punch biopsies were collected from at least one donor site per subject. Histological processing was performed to determine tissue morphometry and quantify collagen composition. Site-specific gene distribution was mapped using targeted gene expression analysis and validated using real time polymerase chain reaction (qPCR). RESULTS: A total of 50 samples from 37 subjects were harvested. Epithelial thickness did not differ between sites. However, lamina propria was thicker in the maxillary tuberosity (2.55 ± 0.92 mm) and retromolar pad (1.98 ± 0.71 mm) than in the lateral palate. Type I collagen was the predominant structural protein in the lamina propria (75.06%-80.21%). Genes involving collagen maturation and extracellular matrix regulation were highly expressed in the maxillary tuberosity and retromolar pad, while lipogenesis-associated genes were markedly expressed in the lateral palate. The retromolar pad showed the most distinct gene expression profile, and the anterior and posterior palate displayed similar transcription profiles. CONCLUSIONS: Tissue samples harvested from the anterior and posterior palate differed morphologically from those from the maxillary tuberosity and retromolar pad. Each intra-oral site showed a unique gene expression profile, which might impact their biological behaviour and outcomes of soft tissue augmentation procedures.

Parents with periodontitis drive the early acquisition of dysbiotic microbiomes in their offspring.

AIM: To evaluate the microbial colonization in different dentition phases on individuals from 0 to 18 years of age belonging to families with a history of periodontitis compared to descendants of periodontally healthy parents. MATERIALS AND METHODS: The offspring of subjects with periodontitis ('Perio' group) and the offspring of periodontally healthy subjects ('Healthy' group), matched for gender and age, were included in this cross-sectional study and divided according to the dentition phase: pre-dentate, primary, mixed and permanent. The patients were clinically assessed, and their saliva was collected. DNA was extracted, and V1-V3 and V4-V5 regions of the 16S rRNA gene were sequenced. RESULTS: Fifty children of parents with periodontitis and 50 from healthy parents were included in the study and divided according to the dentition phase: pre-dentate (n = 5/group), primary dentition (n = 15/group), mixed dentition (n = 15/group) and permanent dentition (n = 15/group) in each group. The microbiome composition was different between dentitions for both groups. Children of the Perio group presented a microbial diversity different from that of the Healthy group in mixed and permanent dentitions. The more intense shift in the community occurred between primary and mixed dentition in the Perio group, while the transition between mixed and permanent dentition was the period with greater changes in the microbiome for the Healthy group. Furthermore, a pathogen-rich environment-higher prevalence and abundance of periodontitis-associated species such as Prevotella spp., Selenomonas spp., Leptotrichia spp., Filifactor alocis, Prevotella intermedia, Treponema denticola and Tannerella forsythia- was observed in the Perio group. CONCLUSIONS: The parents' periodontal status significantly affects the microbiome composition of their offspring from an early age. The mixed dentition was the phase associated with establishing a dysbiotic and pathogen-rich microbiome in descendants of parents with periodontitis.

A commercial SnF2 toothpaste formulation reduces simulated human plaque biofilm in a dynamic typodont model.

AIMS: We present a dynamic typodont biofilm model (DTBM) incorporating (1) human dentition anatomy, (2) fluid flow over intermittently fluid bathed tooth surfaces and (3) an oxic headspace to allow aerobic and anaerobic niches to develop naturally, as a screening tool to assess the effect of stannous fluoride (SnF2 ) toothpaste against a simulated human plaque biofilm (SPB). METHODS AND RESULTS: First, hydroxyapatite (HA) coupons were inoculated with human saliva/plaque and cultured at 37°C under air. Selected species representative of common commensal and anaerobic pathogens were quantified for relative abundance changes over 4 days by PCR densitometry to confirm the culture conditions allowed the proliferation of these species. A continuous culture DTBM reactor on a rocker table was inoculated with saliva/plaque and incubated at 37°C for 24 h. Tooth shear stress was estimated by particle tracking. A SnF2 toothpaste solution, or a sham rise was administered twice daily for 3 days to mimic routine oral hygiene. SPB biomass was assessed by total bacterial DNA and methylene blue (MB) staining. Early colonizer aerobes and late colonizer anaerobes species were detected in the HA and DTBM, and the trends in changing abundance were consistent with those seen clinically. CONCLUSIONS: Treatment with the SnF2 solution showed significant reductions of 53.05% and 54.4% in the SPB by MB staining and DNA, respectively. SIGNIFICANCE AND IMPACT OF STUDY: The model has potential for assessing dentition anatomy and fluid flow on the efficacy of antimicrobial efficacy against localized SPB and may be amenable to the plaque index clinical evaluation.

Microbiomics: Were we all wrong before?

Periodontal microbiology has historically been based on an "us against them" paradigm, one that focuses mainly on identifying microbes and viruses that cause disease. However, such a bottom-up approach limits our appreciation of the incredible diversity of this ecosystem and the essential ways in which microbial interactions contribute to health and homeostasis of the subgingival niche. Microbiomics-the science of collectively characterizing and quantifying molecules responsible for the structure, function, and dynamics of a microbial community-has enabled us to study these communities in their natural habitat, thereby revolutionizing our knowledge of host-associated microbes and reconceptualizing our definition of "human." When this systems-biology approach is combined with ecologic principles, it explicates the complex relationship that exist between microbiota and between them and us, the human. In this volume of Periodontology 2000, a group of 12 female scientists take the lead in investigating how metagenomics, genomics, metatranscriptomics, proteomics, metaproteomics, and metabolomics have achieved the following: (a) widened our view of the periodontal microbiome; (b) expanded our understanding of the evolution of the human oral microbiome; (c) shone a light on not just bacteria, but also other prokaryotic and eukaryotic members of the community; (d) elucidated the effects of anthropogenic behavior and systemic diseases on shaping these communities; and (e) influenced traditional patterns of periodontal therapeutics.

Probing periodontal microbial dark matter using metataxonomics and metagenomics.

Our view of the periodontal microbial community has been shaped by a century or more of cultivation-based and microscopic investigations. While these studies firmly established the infection-mediated etiology of periodontal diseases, it was apparent from the very early days that periodontal microbiology suffered from what Staley and Konopka described as the "great plate count anomaly", in that these culturable bacteria were only a minor part of what was visible under the microscope. For nearly a century, much effort has been devoted to finding the right tools to investigate this uncultivated majority, also known as "microbial dark matter". The discovery that DNA was an effective tool to "see" microbial dark matter was a significant breakthrough in environmental microbiology, and oral microbiologists were among the earliest to capitalize on these advances. By identifying the order in which nucleotides are arranged in a stretch of DNA (DNA sequencing) and creating a repository of these sequences, sequence databases were created. Computational tools that used probability-driven analysis of these sequences enabled the discovery of new and unsuspected species and ascribed novel functions to these species. This review will trace the development of DNA sequencing as a quantitative, open-ended, comprehensive approach to characterize microbial communities in their native environments, and explore how this technology has shifted traditional dogmas on how the oral microbiome promotes health and its role in disease causation and perpetuation.

Interventions to prevent periodontal disease in tobacco-, alcohol-, and drug-dependent individuals.

Substance abuse affects more than one sixth of the world's population. More importantly, the nature of the abuse and the type of addictive substances available to individuals is increasing exponentially. All substances with abusive potential impact both the human immuno-inflammatory system and oral microbial communities, and therefore play a critical role in the etiopathogenesis of periodontal diseases. Evidence strongly supports the efficacy of professionally delivered cessation counseling. Dentists, dental therapists, and hygienists are ideally placed to deliver this therapy, and to spearhead efforts to provide behavioral and pharmacologic support for cessation. The purpose of this review is to examine the biologic mechanisms underlying their role in disease causation, to understand the pharmacologic and behavioral basis for their habituation, and to investigate the efficacy of population-based and personalized interventions in prevention of periodontal disease.

Use of an oxygen planar optode to assess the effect of high velocity microsprays on oxygen penetration in a human dental biofilms in-vitro.

BACKGROUND: Dental plaque biofilms are the causative agents of caries, gingivitis and periodontitis. Both mechanical and chemical strategies are used in routine oral hygiene strategies to reduce plaque build-up. If allowed to mature biofilms can create anoxic microenvironments leading to communities which harbor pathogenic Gram-negative anaerobes. When subjected to high velocity fluid jets and sprays biofilms can be fluidized which disrupts the biofilm structure and allows the more efficient delivery of antimicrobial agents. METHODS: To investigate how such jets may disrupt anoxic niches in the biofilm, we used planar optodes to measure the dissolved oxygen (DO) concentration at the base of in-vitro biofilms grown from human saliva and dental plaque. These biofilms were subject to "shooting" treatments with a commercial high velocity microspray (HVM) device. RESULTS: HVM treatment resulted in removal of much of the biofilm and a concurrent rapid shift from anoxic to oxic conditions at the base of the surrounding biofilm. We also assessed the impact of HVM treatment on the microbial community by tracking 7 target species by qPCR. There was a general reduction in copy numbers of the universal 16S RNA by approximately 95%, and changes of individual species in the target region ranged from approximately 1 to 4 log reductions. CONCLUSION: We concluded that high velocity microsprays removed a sufficient amount of biofilm to disrupt the anoxic region at the biofilm-surface interface.

Correction to: Use of an oxygen planar optode to assess the effect of high velocity microsprays on oxygen penetration in a human dental biofilms in-vitro.

An amendment to this paper has been published and can be accessed via the original article.

Influenza A virus neuraminidase protein interacts with Hsp90, to stabilize itself and enhance cell survival.

Neuraminidase protein (NA) of influenza A virus (IAV) is popularly known for its sialidase function to assist in the release of progeny virus. However, involvement of NA in other stages of the IAV life cycle also indicates its multifunctional nature and necessity to interact with other host proteins. Here, we report a host protein-heat shock protein 90 (Hsp90), as a novel interacting partner of IAV NA. A classical yeast two-hybrid screen was conducted to identify a new host interacting partner for NA and the interaction was further validated by coimmunoprecipitation from cells, transiently expressing both proteins and also from IAV-infected cells. Confocal imaging showed that both proteins colocalized in the cytoplasm in transfected host cells. Interestingly, increased levels of NA in the presence of Hsp90 was observed, which tends to decrease if adenosine triphosphatase activity of Hsp90 is inhibited using 17-N-allylamino-17-demethoxygeldanamycin (17AAG). This establishes viral NA as a client protein of host chaperone Hsp90 contributing toward NA's stability via the NA-Hsp90 interaction. This is the first report showing the interaction of NA with Hsp90 and its role in stabilizing viral NA thus preventing it from degradation. Enhanced cell survival in the presence of this interaction was also observed, thus suggesting the requirement of stable viral NA, post-IAV infection, for efficient virus production in infected mammalian cells.

Systemic Risk Factors for the Development of Periimplant Diseases.

PURPOSE: Although periimplantitis results from the tissue destructive effects of a dysbiotic periimplant microbiome, several factors may either contribute to the dysbiosis or influence the host response to this bacterial challenge and thereby increase the risk of disease. The goal of this narrative review is examine extrinsic factors that might increase the risk at both subject and site levels. MATERIALS AND METHODS: The PubMed (MEDLINE) database was searched for articles examining the influence of systemic conditions on periimplantitis or implant failure. Key search terms included "systemic," "medications," "periodontitis," "dental implant," "periimplantitis," "implant failure" and related terms. Manual searches were also performed for the following journals: Clinical Oral Implants Research, International Journal of Periodontics and Restorative Dentistry, Journal of Clinical Periodontology, International Journal of Oral and Maxillofacial Implants, Implant Dentistry, and Journal of Periodontology. The inclusion criteria were cohort studies and case-control studies with at least 10 participants per group and with at least 6 months of follow-up. RESULTS: Certain systemic diseases, medications, radiotherapy, and behavioral factors, such as oral hygiene and compliance with periodontal maintenance therapy, appear to significantly increase the risk of disease.

The impacts of oral health symptoms, hygiene, and diet on the development and severity of psoriasis.

Numerous studies have suggested a correlation between oral health, the oral microbiome, and various dermatologic conditions, particularly psoriasis. In this study, we utilize a specially designed questionnaire administered to 265 patients at The Ohio State University's dermatology clinics to explore the relationship between psoriasis and a combination of factors that included dietary habits, oral health, and oral hygiene practices. Age, family history of psoriasis, previous diagnosis of strep throat or rheumatoid arthritis, and oral pain or discomfort experienced within the last 12 months were all found to be significant predictors of psoriasis. Additionally, higher body mass index scores, poor gum health, and speech difficulties related to dental problems were all correlated with more severe psoriasis symptoms. Conversely, patients who reported consuming fresh fruit at least once a day experienced milder symptoms. Our goal is to develop a better understanding of how and why psoriasis incidence is correlated with some of the oral health factors under review.

Site-level risk predictors of peri-implantitis: A retrospective analysis.

AIM: The goal of the present investigation was to identify site-level factors that might allow prognostication of individual implants in partially dentate patients with multiple non-splinted restorations. METHODS: We analysed clinical and radiographic characteristics of 222 non-splinted single implants in function for at least 5 years in 86 partially dentate individuals at the time of functional loading and at follow-up, with the outcome variable being peri-implantitis. Principal component analysis identified factors contributing to greatest variability and linear discriminant analysis coupled with Random Forest Classifier used to identify risk predictors. RESULTS: After controlling for patient-level factors, the following characteristics were associated with significantly increased risk for peri-implantitis: Periodontal disease on adjoining teeth at the time of restoration (Odds Ratio (OR): 8.0), implant placement at a depth of 6 mm or more in relation to the CEJ of adjacent tooth (OR: 8.5), asymmetric prosthesis (OR: 4.3), history of tooth loss due to periodontitis (OR: 2.4) and a mean baseline plaque index of 1.6 or more (OR: 7.9). CONCLUSIONS: Our findings suggest that a system that incorporates both subject level and implant-level factors is required to effectively prognosticate the success of individual implants.

Glycaemic status affects the subgingival microbiome of diabetic patients.

AIM: Periodontitis is correlated with type 2 diabetes mellitus (T2DM), but little is known about glycaemic status effect on subgingival microbiota associated with periodontitis. This study evaluated if periodontal microbiome of T2DM patients is affected by glycaemic status. MATERIALS AND METHODS: Twenty-one T2DM non-smoking patients with chronic periodontitis and body mass index ≤40 kg/m2 were allocated into two groups according to systemic glycaemic status: inadequate (DMI- HbA1c ≥ 8%) and adequate (DMA- HbA1c <7.8%). Subgingival biofilm was collected from sites with moderate (PD = 4-6 mm) and severe disease (PD ≥ 7 mm) in two quadrants. The V5-V6 hypervariable region of the 16SrRNA was sequenced using the GS-FLX-454 Titanium platform. Sequences were compared with HOMD database using QIIME and PhyloToAST pipelines. Statistical comparisons were made using two-sample t-tests. RESULTS: DMA microbiome presented higher diversity than DMI. Inadequate glycaemic control favoured fermenting species, especially those associated with propionate/succinate production, whereas those forming butyrate/pyruvate was decreased in DMI. Higher abundances of anginosus group and Streptococcus agalactiae in DMI may indicate that subgingival sites can be reservoir of potentially invasive pathogens. Altered subgingival microbiome in DMI may represent an additional challenge in the periodontal treatment of these patients and in the prevention of more invasive infections. CONCLUSION: Glycaemic status in T2DM patients seems to modulate subgingival biofilm composition.

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.