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Previous issue date: 2014-11-03 / The presence of bacterial endotoxin (LPS) in the root canal system is related to the maintenance and evolution of the pulp and periapical diseases. So far, there is none technical or material that is completely effective in eliminating the LPS. Therefore, in order to enhance the disinfection process, and thereby, to increase the success rate of endodontic treatment, it has been sought alternatives to clinical protocols held nowa-days. The use of auxiliary equipments with principles of action based on electrofulguration and in the potential application of ozone gas appears as an alterna-tives. Thus, the first article of this thesis initially sought to verify the feasibility for the use of bovine teeth instead of human teeth, in in vitro experiments with contamination by LPS, because there are no studies in the literature using this methodology. For this, twenty bovine (B) central incisors and twenty single-rooted human (H) premolars had removed their dental crowns and standardized their root length to 16 mm. The root ca-nals were prepared until size 60 K-type instrument and subjected to sterilization by gamma irradiation with 60 cobalt. According to the two types of dental species, the teeth were randomly divided into two subgroups, positive (P) and negative (N). The root canals of the positive groups (HP and BP) were inoculated with Escherichia coli LPS (O55:B5). The root canals of negative groups (HN and BN) were exposed only to a py-rogenic water. After the teeth incubation in a 37?C atmospheric humidity during 24 hours, the samples of the solutions from the main root canals were collected with a py-rogenic absorbent paper points. The quantification of the levels of LPS was made by Limulus Amebosytes Lysate (LAL) and data were subjected to oneway ANOVA, fol-lowed by Tukey post hoc, with a 5% significance level. The results showed significant differences (P<0,001) between the two experimental models. The use of bovine teeth showed not to be the best option for LPS contamination studies. Following this result, a second article of the Thesis was performed in order to verify the effect of ozone gas (OZY? system) and high frequency electric pulses (Endox? System) in human root canals previously contaminated by LPS. Fifty single-rooted premolars received the same protocol for root canals preparation, as reported in the first article. Once ready, the specimens were divided into five groups (n=10), according to the disinfection protocol established: OZY? System, one 120-second-pulse (OZY 1p); OZY? System, four 24-second-pulses (OZY 4p); Endox? System (ENDOX). Contaminated and non-contaminated canals, exposed only to apyrogenic water, were used as positive (C+) and negative (C-) controls, respectively. The Escherichia coli LPS (O55:B5) was inoculated into the root canals, except in the C- group teeth. After performing the disinfection pro-tocols, fluid samples were collected from the canals using apyrogenic paper tips. The method for quantification of LPS levels and statistical analysis were the same as de-scribed in the first article. The results showed that the disinfection protocols were una-ble to reduce significantly the LPS levels. The use of ozone gas and high frequency electric pulses were not effective in the elimination of LPS in root canals. / A presen?a da endotoxina (LPS) bacteriana no sistema de canais radiculares est? relacionada com a manuten??o e evolu??o das doen?as pulpares e periapicais. At? o momento, n?o h? nenhuma t?cnica ou material que seja completamente eficaz na elimina??o do LPS. Logo, com objetivo de aprimorar o processo de desinfec??o e, consequentemente, aumentar as taxas de sucesso no tratamento endod?ntico, tem-se buscado alternativas aos protocolos cl?nicos realizados atualmente. A utiliza??o de equipamentos auxiliares com princ?pios de a??o baseados na eletrofulgura??o e no potencial de aplica??o do g?s oz?nio surge como alternativas. Sendo assim, o primeiro artigo desta tese buscou, inicialmente, verificar a viabilidade para utiliza??o de dentes bovinos ao inv?s de humanos, em experimentos in vitro com contamina??o por LPS, tendo em vista n?o haver estudos na literatura com essa metodologia. Para isso, vinte incisivos centrais bovinos (B) e vinte pr?-molares monorradiculares humanos (H) tive-ram suas coroas dent?rias removidas e comprimento radicular padronizado em 16 mm. Os canais radiculares foram preparados at? o instrumento tipo K n?. 60 e submetidos ? esteriliza??o por radia??o gama com cobalto 60. De acordo com os dois tipos de esp?-cies dent?rias, os dentes foram divididos aleatoriamente em dois subgrupos, positivo (P) e negativo (N). Os canais dos grupos positivos (HP e BP) foram inoculados com LPS de Escherichia coli (O55:B5). J? os canais dos grupos negativos (HN e BN) foram apenas expostos ? ?gua apirog?nica. Ap?s a incuba??o dos dentes, a 37?C, com umidade atmosf?rica durante 24 horas, amostras das solu??es do canal principal foram coletadas com pontas de papel absorvente apirog?nicas. A quantifica??o dos n?veis de LPS foi feita por Limulus Amebosytes Lisado (LAL) e os dados obtidos foram submetidos ? ANOVA de uma via, seguido de Post Hoc Tukey, com n?vel de signific?ncia de 5%. Os resultados demonstraram que houve diferen?a significativa (P<0,001) entre os dois modelos experimentais. A utiliza??o de dentes bovinos n?o apresentou ser a melhor op??o dent?ria para pesquisas laboratoriais com contamina??o por LPS. Foi realizado, ent?o, o segundo artigo da Tese a fim de verificar o efeito do g?s oz?nio (sistema OZY?) e de pulsos el?tricos de alta frequ?ncia (sistema Endox?) em canais radiculares humanos previamente contaminados com LPS. Cinquenta pr?-molares unirradiculares receberam o mesmo protocolo para preparo da amostra relatado no primeiro artigo. Depois de prontos, os esp?cimes foram divididos em cinco grupos (n=10), de acordo com o protocolo de desinfec??o institu?do: Sistema OZY?, um pulso de 120 segundos (OZY 1p); Sistema OZY?, quatro pulsos de 24 segundos (OZY 4p); Sistema Endox? (EN-DOX). Canais contaminados e n?o contaminados, apenas expostos ? ?gua apirog?nica, foram utilizados como controle positivo (C+) e negativo (C-), respectivamente. O LPS de Escherichia coli (O55:B5) foi inoculado nos canais radiculares, exceto nos dentes do grupo C-. Ap?s os protocolos de desinfec??o, amostras do flu?do foram coletadas dos canais com pontas de papel apirog?nicas. O m?todo para quantifica??o dos n?veis de LPS e a an?lise estat?stica empregada tamb?m foram os mesmos descritos no primeiro artigo. Os resultados mostraram que os protocolos de desinfec??o n?o foram capazes de reduzir significativamente os n?veis de LPS. O uso do g?s oz?nio e de pulsos el?tricos de alta frequ?ncia n?o foram eficazes na elimina??o do LPS em canais radiculares.
| Identifer | oai:union.ndltd.org:IBICT/oai:tede2.pucrs.br:tede/1277 |
| Date | 03 November 2014 |
| Creators | Melo, Tiago Andr? Fontoura de |
| Contributors | Figueiredo, Jos? Antonio Poli de |
| Publisher | Pontif?cia Universidade Cat?lica do Rio Grande do Sul, Programa de P?s-Gradua??o em Odontologia, PUCRS, BR, Faculdade de Odontologia |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da PUC_RS, instname:Pontifícia Universidade Católica do Rio Grande do Sul, instacron:PUC_RS |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | -8096554818733665164, 500, 600, 4673435736271820140 |
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