AbstractINTERLEUKIN-6 LEVELS IN GENERALIZED AND LOCALIZED AGGRESSIVE PERIODONTITIS PATIENTSBy Bindu Reddy, D.D.S.A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science at the Virginia Commonwealth UniversityVirginia Commonwealth University, 2004Major Director: Joseph V. Califano, D.D.S., Ph.D.Associate Professor, Department of Periodontics Periodontitis is an inflammatory disease involving the supporting structures of the dentition. Many studies have shown that there is a relationship between periodontal disease, the presence of pro-inflammatory cytokines, and systemic disease such as cardiovascular disease and diabetes mellitus. The purpose of this study was to measure serum Interleukin-6 levels in generalized and localized aggressive periodontitis and non-periodontitis patients and look for relationships with measures of disease severity. We also examined variables known to have a relationship with IL-6. A total of 172 subjects, comprising three periodontal subgroups, non-periodontitis (NP=61), generalized aggressive periodontitis (GAP=77), and localized aggressive periodontitis (LAP= 34), had serum samples evaluated for IL-6 levels using a highly sensitive ELISA test. The IL-6 levels were compared with clinical and demographic data including age, race, gender, number of teeth, probing depth, attachment loss, bleeding index, plaque index, gingival index, cotinine levels, smoking status, and CRP levels. Using multiple regression analysis, smoking status (p=0.0015) was the only variable found to have a significant relationship with IL-6 levels for all three groups.

Fatores microbianos, mecânicos e intrínsecos ao hospedeiro são os responsáveis pelo insucesso endodôntico e necessidade de reintervenção. Polimorfismos genéticos são diferenças na sequência do DNA humano que influenciam na susceptibilidade do organismo frente a doenças e nas suas respostas ao meio ambiente. O objetivo do presente estudo foi investigar o envolvimento de aspectos moleculares e clínicos na resposta do hospedeiro frente ao tratamento endodôntico, por meio da análise da expressão e frequência de polimorfismos dos genes reguladores do processo de remodelação óssea em pacientes submetidos ao tratamento endodôntico. Pacientes que apresentaram necrose pulpar e lesão periapical instalada no momento do tratamento endodôntico foram chamados para consulta de acompanhamento. Foram incluídos no presente estudo 150 pacientes, que apresentaram tratamento concluído há no mínimo um ano antes da consulta de acompanhamento. Desse total, 64 pacientes apresentaram sinais e sintomas clínicos/radiográficos indicativos de lesões periapicais persistentes, e 86 indivíduos apresentaram reparação da lesão. No momento do acompanhamento, foram coletas amostras de saliva dos pacientes como fonte de DNA genômico, o qual foi extraído a partir do pellet de células sedimentado e genotipado para RANK (rs3826620), RANKL (rs9594738) e OPG (rs2073618) por PCR em tempo real. A frequência dos genótipos e alelos foi avaliada por meio da razão de chance (odds ratio), teste do qui-quadrado ou teste exato de Fisher, utilizando os softwares Epi Info 3.5.2 e Graphpad Prism. O tempo de acompanhamento após o tratamento foi utilizado como covariável na análise de regressão logística múltipla para cada um dos polimorfismos. O nível de significância estabelecido foi de 5%. Foi observada associação na distribuição dos alelos do polimorfismo em RANK entre os grupos (p=0,04). No polimorfismo em RANKL, a distribuição dos genótipos apresentou diferença estatisticamente significante entre os grupos (p=0,05). O tempo de acompanhamento esteve associado aos casos de lesões periapicais persistentes para cada um dos polimorfismos analisados (p<0,05), sendo que na análise ajustada pelo tempo como covariável, os polimorfismos rs3826620 em RANK (p=0.02) e rs9594738 em RANKL (p=0.03) continuaram associados a lesões periapicais persistentes. O polimorfismo rs2073618 em OPG não foi associado a distribuição dos grupos em nenhuma das análises (p>0,05). Conclui-se que polimorfismos em RANK e RANKL estão associados ao risco do desenvolvimento de lesões periapicais persistentes / Microbial, mechanical and related to host response factors are responsible for endodontic failure and requirement for reintervention. Genetic polymorphisms are differences in the sequence of human DNA that influence in the susceptibility to diseases and host response to the environment. The aim of this study was to evaluate the association between molecular and clinical aspects in the host response to root canal therapy (RCT), by analyzing the expression and frequency of polymorphisms of genes regulating the bone remodeling process in patients submitted to endodontic treatment. Patients that presented pulp necrosis and apical periodontitis at the time of RCT, with at least 1 year of follow-up after RCT were recalled. Sixty-four subjects with signs/symptoms of PAP and 86 subjects with root canaltreated teeth exhibiting healthy perirradicular tissues (healed) were included. At the time of follow-up visit, saliva samples from patients were collected as a source of genomic DNA, which was extracted from the pellet of sedimented cells and used for RANK (rs3826620), RANKL (rs9594738) and OPG (rs2073618) genotyping by real-time PCR. Genotype and allele frequencies were compared by chi-square test or Fishers exact tests and odds ratio was implemented, using Epi Info 3.5.2 and Graphpad Prism. A logistic regression analysis was also performed using time of follow-up as co-variate. All tests were performed with an established alpha of 0.05. An association between allele distribution and the polymorphism in RANK was observed. Subjects that carry the allele T had a lower risk to have PAP (p=0.04). In RANKL polymorphism, the genotype distribution was statistically significant different between PAP and healed groups (p=0.05). Time of follow-up was associated with PAP (p<0.05). In the logistic regression analysis using time as a co-variant, RANK rs3826620 (p=0.02) and RANKL rs9594738 (p=0.03) were associated with PAP. The polymorphism rs2073618 in OPG was not associated with PAP (p>0.05). We conclude that polymorphisms in RANK and RANKL are associated with the risk of developing persistent periapical lesions