Influence of 2% chlorhexidine gel on pH, calcium release and ability of reducing endotoxin of calcium hydroxide

Orientadores: Rogerio de Castilho Jacinto, Brenda Paula Figueiredo de Almeida GomesDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: O presente estudo avaliou a influência da clorexidina 2% gel (CLX) sobre as propriedades químicas como pH e liberação de íons cálcio do hidróxido de cálcio, e sobre a capacidade de redução de endotoxinas desta medicação intracanal. A liberação do cálcio do Ca(OH)2 + soro ou associado a CLX foi verificada pela espectrofotometria por absorção atômica e o pH através do emprego de um peagâmetro. As mensurações foram realizadas nos períodos experimentais de 24 horas, 7, 15 e 30 dias. Para a quantificação de endotoxinas foram utilizados dentes humanos, previamente preparados, contaminados, preenchidos com as medicações. Os medicamentos foram inseridos dentro dos canais de 30 dentes (GI Ca(OH)2 + soro, GII Ca(OH)2 + CLX, GIII CLX), e após permanecerem por 14 dias foram removidos com irrigação abundante. Este lavado foi submetido à quantificação da endotoxina remanescente através do teste cromogênico quantitativo QLC-1000. Análise estatística foi realizada com os testes ANOVA e Tuckey (p0.05). Os maiores valores de pH foram observados após 30 dias para o Ca(OH)2 + soro. Os valores mais baixos de pH foram apresentados pela clorexidina 2% gel quando testada sozinha, em todos os períodos. Um aumento significativo no pH foi observado no intervalo de 24 horas e 7 dias, tanto para o Ca(OH)2 + soro quanto para Ca(OH)2 + CLX. A maior redução de endotoxinas foi observada no grupo da clorexidina 2% gel (91,63%), seguida de sua associação com o Ca(OH)2 (88,76%) e depois o Ca(OH)2 + soro fisiológico (82,13%). Não houve diferença estatística entre a clorexidina 2% gel e sua associação com o hidróxido de cálcio, quanto à redução da quantidade de endotoxinas dentro do canal radicular. Concluiu-se que a clorexidina 2% gel não interferiu no pH e liberação de íons cálcio do hidróxido de cálcio quando em associação com este. Além disso, melhorou a capacidade do hidróxido de cálcio em reduzir o conteúdo de endotoxinas dos canais radiculares in vitro.Abstract: The aim of the present study was to evaluate the influence of 2% chlorhexidine gel (CHX) on chemical properties of calcium hydroxide and on its ability of reducing endotoxic content of root canals when used as intracanal medicament. The amount of calcium released from the pastes was assessed by atomic absorbance spectophotometry and the pH was verified in pHmeter. The tested periods were 24 hours and 7, 15 and 30 days. For the endotoxin quantification assay, single rooted teeth were previously inoculated with endotoxins and then with intracanal medication. The medicaments were placed inside the root canal of 30 teeth, (GI - Ca(OH)2 + 0.9% saline solution, GII - Ca(OH)2 + CHX and GIII - CHX), and were removed after 14 days, with copiously irrigation. The removed solution was submitted to the chromogenic quantitative endotoxin test QCL-1000 Statistical analysis was performed with ANOVA and Tuckey Test (p0.05). The highest pH values were observed after 30 days for the association between Ca(OH)2 + saline solution. The lowest values of pH were observed for 2% chlorhexidine gel, in all periods. A higher increase of pH was stated between 24 h and 7 days for Ca(OH)2+ saline solution and Ca(OH)2+ CHX, and remained unaltered until the end of the experiment for both pastes. A higher reduction in the endotoxin content was observed in the CHX group (91.63%), followed by Ca(OH)2+ CHX (88,76%) and Ca(OH)2 + saline solution (82.13%). There were no statistical difference between 2% chlorhexidine gel and its association with calcium hydroxide over the endotoxin content reduction inside the root canal. According to the results, it can be concluded that 2% chlorhexidine gel did not interfere in the chemical properties of calcium hydroxide. Moreover, chlorhexidine was also able to improve calcium hydroxide properties for reducing the endotoxic content of root canals in vitro.MestradoEndodontiaMestre em Clínica Odontológic

Prevalence of treponema Spp. in endodontic retreatment-resistant periapical lesions

This study investigated the presence of the Treponema species in longstanding endodontic retreatment-resistant lesions of teeth with apical periodontitis, the association of this species with clinical/radiographic features, and the association among the different target species. Microbial samples of apical lesions were collected from twenty-five adult patients referred to endodontic surgery after unsuccessful root canal retreatment. Nested-PCR and conventional PCR were used for Treponema detection. Twenty-three periradicular tissue samples showed detectable levels of bacterial DNA. Treponema species were detected in 28% (7/25) of the cases. The most frequently detected species were T. socranskii (6/25), followed by T. maltophilum (3/25), T. amylovorum (3/25), T. lecithinolyticum (3/25), T. denticola (3/25), T. pectinovorum (2/25) and T. medium (2/25). T. vicentii was not detected in any sample. Positive statistical association was found between T. socranskii and T. denticola, and between T. maltophilum and T. lecithinolyticum. No association was detected between the presence of any target microorganism and the clinical or radiographic features. Treponema spp. are present, in a low percentage, in longstanding apical lesions from teeth with endodontic retreatment failure291CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES302575/2009-0sem informaçã

Microbiological evaluation of chronic periapical lesions associated with unsuccessful endodontic retreatment

Orientadores: Rogério de Castilho Jacinto, Brenda Paula Figueiredo de Almeida GomesTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: O conhecimento do perfil microbiano envolvido na periodontite apical persistente pode auxiliar no estabelecimento de protocolos mais eficazes na conduta endodôntica. Através de um relato de caso clínico e da avaliação de 20 casos de periodontite apical persistente após retratamento endodôntico, foram objetivos deste trabalho: identificar bactérias viáveis em lesões periapicais persistentes e correlacionar os achados microbiológicos com o diagnóstico histopatológico da lesão. Métodos: No relato de caso o dente foi submetido ao retratamento endodôntico através da técnica de crown-down com o uso de substância química auxiliar (clorexidina 2% gel), patência e alargamento foraminal e obturação dos canais em sessão única. Após persistência da fístula foi indicada apicectomia, que foi realizada sob magnificação e retro-obturação com MTA. O fragmento apical da raiz distal foi observado por microscopia eletrônica de varredura e foi realizada cultura microbiana da lesão curetada (capítulo 1). Foram selecionados 20 pacientes com necessidade de cirurgia parendodôntica, submetidos à coleta durante a curetagem do tecido periapical. As amostras foram processadas microbiologicamente por técnicas de cultura microbiana e enviadas para diagnóstico histológico (capítulo 2). Resultados: No capítulo 1 as seguintes espécies foram encontradas: Actinomyces naeslundii e Actinomyces meyeri, Propionibacterium propionicum, Clostridium botullinum, Parvimonas micra e Bacteroides ureolyticus; a análise em microscopia eletrônica de varredura revelou biofilme bacteriano circundante ao forame apical e superfície radicular externa. O trespasse de guta-percha no zip apical causado durante o primeiro tratamento também foi observado. A proservação radiográfica após seis meses mostrou reparo periapical aparente, o qual foi confirmado após 24 meses. No capítulo 2 foram encontrados mais cistos (13/20) do que granulomas (7/20). A cultura microbiológica e testes bioquímicos específicos puderam identificar 83 bactérias cultiváveis divididas em 33 espécies bacterianas distintas. As lesões demonstraram uma infecção de caráter misto, composta em sua maior parte por microrganismos anaeróbios estritos (80,4% em cistos e 65% em granulomas) e Gram-positivos (70,6% em cistos e 84,4% em granulomas). Embora se tenha isolado até sete espécies bacterianas em uma única lesão (granuloma), na maioria dos casos, quatro (25%) ou cinco (35%) espécies foram encontradas simultaneamente. Os dados foram analisados estatisticamente através do teste exato de Fisher e chi-quadrado de Pearson (P<.05). Conclusões: Bactérias Gram-positivas anaeróbias estritas e o biofilme extrarradicular parecem participar da etiologia do insucesso do tratamento endodôntico. O retratamento endodôntico seguido de microcirurgia periapical constitui uma alternativa de sucesso na resolução de infecções extrarradiculares persistentes (capítulo 1). Embora os cistos tenham sido mais frequentes que granulomas nos casos de insucesso do retratamento endodôntico, bactérias foram isoladas em ambos os tipos de lesão, com uma predominância de espécies gram-positivas, sugerindo que as mesmas são capazes de sobreviver fora do canal radicular e podem estar relacionadas com a persistência do processo patológico, mesmo após um retratamento endodôntico acurado (capítulo 2)Abstract: The knowledge of the microbial profile of persistent apical periodontitis allows the development of more efficient endodontic therapy. Through the evaluation of a case report and 20 cases of persistent apical periodontitis after endodontic retreatment, the objectives of this study were: to identify viable bacteria in persistent periapical lesions and correlate microbiological findings with histopathological diagnosis. Methods: In the case report, the tooth had undergone endodontic retreatment by the crown-down technique with the use of auxiliary chemical substance (2% chlorhexidine gel), foraminal patency and enlargement and filling of root canals in a single session. After persistence of sinus tract apicoectomy was indicated, which was performed under magnification and retro-filled with MTA. Apical fragment of the distal root was observed by scanning electron microscopy and excised tissue processed for microbial identification (Chapter 1). Twenty patients requiring endodontic surgery were selected. The samples were processed by microbiological techniques from microbial culture and sent for histological diagnosis (Chapter 2). Results: In chapter 1 the following species were found: Actinomyces naeslundii and Actinomyces meyeri, Propionibacterium propionicum, botullinum Clostridium, Parvimonas micra and Bacteroides ureolyticus; SEM analysis of the root end showed bacterial biofilm surrounding the apical foramen and external root surface. Gutta-percha in the apical zip caused during the first treatment was also observed. Six months follow-up showed apparent periapical repair, which was confirmed after 24 months. In chapter 2 more cysts (13/20) than granulomas (7/20) were found. Culture tests were able to identify 83 specific cultivable bacteria divided into 33 different bacterial species. The microbial characterization showed a mixed infection, composed mostly by strict anaerobes (80.4% in cysts and granulomas in 65%) and gram-positive (70.6% in cysts and granulomas in 84.4%). Although up to seven bacterial species in a single lesion (granuloma) has been isolated, in most cases, four (25%) or five (35%) species have been found. Data were statistically analyzed using Fisher's exact test and Pearson chi-square test (P<.05). Conclusions: Gram-positive bacteria and extra-radicular biofilms seem to participate in the etiology of endodontic retreatment failure. The endodontic retreatment followed by micro-periapical surgery proved to be a successful alternative in the resolution of extra-root persistent infections (Chapter 1). Although cysts were more frequent than granulomas in cases of failure of the endodontic retreatment, bacteria were isolated from both types of lesions, with a predominance of gram-positive species, suggesting that these species can survive outside the root canal and might be related with the persistence of the pathological process even after accurate endodontic retreatment (Chapter 2)DoutoradoEndodontiaDoutora em Clínica Odontológic

Prevalence of Treponema spp. in endodontic retreatment-resistant periapical lesions

This study investigated the presence of the Treponema species in longstanding endodontic retreatment-resistant lesions of teeth with apical periodontitis, the association of this species with clinical/radiographic features, and the association among the different target species. Microbial samples of apical lesions were collected from twenty-five adult patients referred to endodontic surgery after unsuccessful root canal retreatment. Nested-PCR and conventional PCR were used for Treponema detection. Twenty-three periradicular tissue samples showed detectable levels of bacterial DNA. Treponema species were detected in 28% (7/25) of the cases. The most frequently detected species were T. socranskii (6/25), followed by T. maltophilum (3/25), T. amylovorum (3/25), T. lecithinolyticum (3/25), T. denticola (3/25), T. pectinovorum (2/25) and T. medium (2/25). T. vicentii was not detected in any sample. Positive statistical association was found between T. socranskii and T. denticola, and between T. maltophilum and T. lecithinolyticum. No association was detected between the presence of any target microorganism and the clinical or radiographic features. Treponema spp. are present, in a low percentage, in longstanding apical lesions from teeth with endodontic retreatment failure