Efeito do pré-tratamento da dentina sobre a engenharia de tecido pulpar humano

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde, Programa de Pós-Graduação em Odontologia, Florianópolis, 2016.No tratamento endodôntico de dentes permanentes imaturos despolpados o preparo mecânico do canal é desaconselhado para não fragilizar ainda mais a estrutura dental. A abordagem clássica permite a desinfecção do canal radicular pelo preparo químico com soluções antimicrobianas e medicação intracanal, mas não a retomada do processo de rizogênese para a complementação do canal radicular. A neoformação de tecido pulpar, por abordagem de engenharia tecidual, tem potencial para melhor resolver essas situações clínicas. Com o uso do Modelo de Fatia Dental/Arcabouço para Engenharia de Tecido Pulpar o objetivo deste trabalho foi desenvolver polpas dentais com morfologia e função semelhantes àquelas do tecido original, em dentinas submetidas a tratamentos com diferentes materiais endodônticos. Para tanto, após o acesso endodôntico e a aplicação dos protocolos de tratamento com hipoclorito de sódio, EDTA, pasta de hidróxido de cálcio ou triantibiótica, fatias de 1 mm de espessura foram obtidas da região cervical de molares, seguido pela produção de arcabouço sintético no espaço da câmara pulpar e semeadura de células-tronco de polpa de dentes permanentes humanos (DPSC). O conjunto fatia dental/arcabouço/células foi implantado em tecido subcutâneo de camundongos. Depois de 35 dias, os implantes foram removidos e processados para análise histo-morfológica, imuno-histoquímica, e microscopia eletrônica confocal. Os resultados das análises histológicas mostraram que houve formação tecidual em todos os grupos, com destaque para o grupo tratado pela pasta Triantibiótica. Da análise em microscopia confocal conclui-se que, mesmo quando tratada por soluções irrigadoras ou pastas antimicrobianas, a dentina apresentou condições de servir como substrato para a sobrevivência e a diferenciação das DPSC em odontoblastos funcionais, com capacidade de deposição de matriz dentinária.Abstract : In the endodontic treatment of immature permanent teeth, mechanical preparation of the root canal is not recommended to do not further weaken the tooth structure. The classical approach allows the disinfection of the root canal by chemical preparation with antimicrobial solutions and intracanal dressing, but not the resumption of the root formation process for the completion of root canal. The pulp tissue neoformation by tissue engineering approach has the potential of better solving these clinical situations. Using the Tooth Slice/Scaffold Model for Dental Pulp Tissue Engineering, the aim of this study was to develop dental pulps with similar morphology and function to those of the original tissue, in dentin subjected to treatments with different materials. For this purpose, after the endodontic access and application of the treatment protocols with sodium hypochlorite, EDTA, calcium hydroxide or triple antibiotic pastes, 1 mm slices from the cervical region of third molars were obtained, followed by the production of a synthetic polymeric scaffold within the pulp chamber and seeding of dental pulp stem cells from human permanent teeth (DPSC). Tooth slice/scaffold/cells sets were implanted subcutaneously in mice. After 35 days, the implants were retrieved and processed for histo-morphological, immunohistochemical, and confocal electron microscopy analyzes. The results of histological analyzes showed that there was tissue formation in all groups, especially the group treated by triple antibiotic paste. From the confocal microscopy analysis, it was concluded that even when treated by irrigating solutions or antimicrobial pastes, dentin is able to serve as substrate for survival and differentiation of DPSC in functional odontoblasts, with dentin matrix deposition capacity

Difusão de íons hidroxila através da dentina radicular nos casos de retratamento endodôntico: estudo ex vivo

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde. Programa de Pós-Graduação em OdontologiaO objetivo desta pesquisa foi avaliar a difusão, através da dentina radicular, de íons hidroxila provenientes da pasta de hidróxido de cálcio (HC) colocada no canal radicular antes da obturação, efetuada com diferentes materiais, e após a remoção do material obturador e reinstrumentação endodôntica. Sessenta canais radiculares foram modelados pela técnica escalonada sob irrigação com hipoclorito de sódio 1% (HS). No final da instrumentação, os canais foram irrigados com ácido etilenodiaminotetracético (EDTA) 17% e HS para a remoção da smear layer. A camada de cemento foi removida, a superfície radicular foi lavada com EDTA e os 3 mm apicais de cada raiz foram cobertos com um adesivo de presa rápida. Os canais foram preenchidos com HC e, após o selamento das cavidades de acesso, os dentes foram lavados e colocados em frascos individuais contendo 10 mL de água destilada, que teve seu pH medido após 7, 14, 21 e 28 dias (HC1). Após a remoção da pasta de HC, os canais foram divididos em cinco grupos iguais e obturados com Resilon/Real Seal (G1), guta-percha e cimento Endofill (G2), Sealapex (G3), AH Plus (G4) e MTA Fillapex (G5). Depois do armazenamento por 7 dias a 37°C em 100% de umidade relativa, o material obturador foi removido, os canais reinstrumentados, irrigados com EDTA e HS, e secos. A pasta de HC foi novamente inserida no canal e, depois do selamento, os dentes foram colocados em frascos contendo novos 10 mL de água destilada. Novamente o pH da água foi medido aos 7, 14, 21 e 28 dias (HC2). As leituras de pH inicial e final (HC1 e HC2) foram comparadas pelos testes ANOVA, ANOVA2 e Tuckey (p < 0,05). Os resultados revelaram que tanto as medidas HC1, como as HC2, aumentaram com o tempo; as medidas obtidas após a reinstrumentação (HC2) foram significativamente superiores às obtidas antes da obturação (HC1), exceto nas amostras dos canais obturados com Sealapex. Foi concluído que os íons hidroxila são capazes de se difundir pela dentina radicular; independentemente do cimento empregado, foi possível restabelecer a permeabilidade dentinária à difusão iônica após a reinstrumentação dos canais; o tempo influiu positivamente na difusão iônica.The aim of this research was to evaluate the diffusion through radicular dentine of hydroxyl ions from calcium hydroxide paste (CHP) placed in root canal before root canal filling by different materials and after the removal of the filling material and re-instrumentation. Sixty root canals were prepared by step-back technique, 1 mm short of the apical foramen under irrigation with sodium hypochlorite 1% (SH). At the end of instrumentation, the root canals were irrigated with ethylenediaminetetraacetic acid (EDTA) 17% and SH for smear layer removal. The cementum layer was removed, the root surface was washed with EDTA, and the apical 3 mm of each root were covered with a fast-setting adhesive. The canals were filled with CHP, and after sealing the access openings, the teeth were washed and placed in individual vials containing 10 mL of distilled water, which had its pH measured after 7, 14, 21 and 28 days (CH1). After removal of CHP, the root canals were divided into five equal groups and filled with Resilon/Real Seal (G1), gutta-percha and Endofill (G2), Sealapex (G3), AH Plus (G4) and MTA Fillapex (G5) sealers. After storage for 7 days at 37°C in 100% relative humidity, the root canal filling was removed and the root canals were re-instrumented. After the final irrigation with EDTA and SH, the CHP was again inserted into the canals, the teeth sealed, washed and placed in new vials containing 10 mL of distilled water. Again the pH of water was measured at 7, 14, 21 and 28 days (CH2). The initial and final pH readings (CH1 and CH2) were compared by ANOVA, ANOVA2 e Tuckey tests (p < 0.05). The results showed that the CH1 and CH2 measurements increased with time; the measurements obtained after re-instrumentation (CH2) were significantly higher than those obtained before root canal filling (CH1), except for the canals filled with Sealapex. It was concluded that hydroxyl ions are able to diffuse through radicular dentine; regardless of the filling material, it was possible to re-establish dentin permeability to ionic diffusion after re-instrumentation; the time had a positive influence on the ionic diffusion

Crown discoloration promoted by materials used in regenerative endodontic procedures and effect of dental bleaching: spectrophotometric analysis

Regenerative endodontic procedure (REP) has been proposed as a new approach to treat immature permanent teeth. However, materials used in REP for root canal disinfection or cervical sealing may induce tooth discoloration. Objectives To assess tooth crown’s color after intracanal treatment with triple antibiotic paste (TAP) or calcium hydroxide (CH); cervical sealing with glass ionomer cement (GIC) or mineral trioxide aggregate (MTA); and bleaching with carbamide peroxide. Material and Methods After pulp removal and color spectrophotometer measurement, 50 bovine incisors were divided into 4 experimental groups and one control (untreated). Experiments were performed in phases (Ph). Ph1: TAP (ciprofloxacin, metronidazole, minocycline), TAPM (ciprofloxacin, metronidazole, amoxicillin), DAP (ciprofloxacin, metronidazole), or CH treatment groups. After 1 and 3 days (d); 1, 2, 3 weeks (w); and 1, 2, 3 and 4 months (m), color was measured and medications were removed. Ph2: GIC or MTA cervical sealing, each using half of the specimens from each group. Color was assessed after 1d, 3d; 1w, 2w, 3w; 1m and 2m. Ph3: Two bleaching sessions, each followed by color measurement. Data were analyzed with ANOVA and post-hoc Holm-Sidak method. Results Ph1: Specimens of TAP group presented higher color alteration (ΔE) mean than those of TAPM group. No significant difference was found among TAP or TAPM and CH, DAP or Control groups. Ph2: cervical sealing materials showed no influence on color alteration. Ph3: Different ΔE means (from different groups), prior to bleaching, became equivalent after one bleaching session. Conclusions TAP induces higher color alteration than TAPM; color alteration increases over time; cervical sealing material has no influence on color alteration; and, dental bleaching was able to recover, at least partially, the tooth crown’s color

É possível alcançarmos a blindagem coronária em dentes tratados endodonticamente? – revisão de literatura Is it possible to achieve coronary shielding in endodontically treated teeth? – literature review

Introduction: The coronary shield, known as the intra-orifice barrier, is defined as a placement of a restorative material at the entrance of the root canal orifice after 3mm of gutta-percha and aiming to increase the resistance of the tooth to the fracture in addition to preventing coronary infiltration. Objective: to report and discuss the existing data in the dental literature regarding the materials available to perform the intra-orifice barrier in endodontically treated teethand to indicate if the desired coronary shield is really achievable. Literature review: The materials analyzed were composite resin, glass ionomer cement (CIV), zinc oxide based materials, silver amalgam and mineral trioxide aggregate (MTA). Results: composites of resin and bulkfill / flow in their results when compared with other materials like MTA. Silver amalgam, zinc oxide-based materials, and CIV do not result in terms of intra-orifice barrier. MTA was favorable in relation to microleakage, but did not reinforce a root structure. Conclusion: No material restorer is able to completely protect the infiltrations.However, as conventional composite resins and bulk-fill flow are the materials with the best properties associated with satisfactory results, however, the need for scientific studies comparing the materials used as an intra-orifice barrier.Introduction: The coronary shield, known as the intra-orifice barrier, is defined as a placement of a restorative material at the entrance of the root canal orifice after 3mm of gutta-percha and aiming to increase the resistance of the tooth to the fracture in addition to preventing coronary infiltration. Objective: to report and discuss the existing data in the dental literature regarding the materials available to perform the intra-orifice barrier in endodontically treated teethand to indicate if the desired coronary shield is really achievable. Literature review: The materials analyzed were composite resin, glass ionomer cement (CIV), zinc oxide based materials, silver amalgam and mineral trioxide aggregate (MTA). Results: composites of resin and bulkfill / flow in their results when compared with other materials like MTA. Silver amalgam, zinc oxide-based materials, and CIV do not result in terms of intra-orifice barrier. MTA was favorable in relation to microleakage, but did not reinforce a root structure. Conclusion: No material restorer is able to completely protect the infiltrations.However, as conventional composite resins and bulk-fill flow are the materials with the best properties associated with satisfactory results, however, the need for scientific studies comparing the materials used as an intra-orifice barrier

Crown discoloration promoted by materials used in regenerative endodontic procedures and effect of dental bleaching: spectrophotometric analysis

Abstract Regenerative endodontic procedure (REP) has been proposed as a new approach to treat immature permanent teeth. However, materials used in REP for root canal disinfection or cervical sealing may induce tooth discoloration. Objectives To assess tooth crown’s color after intracanal treatment with triple antibiotic paste (TAP) or calcium hydroxide (CH); cervical sealing with glass ionomer cement (GIC) or mineral trioxide aggregate (MTA); and bleaching with carbamide peroxide. Material and Methods After pulp removal and color spectrophotometer measurement, 50 bovine incisors were divided into 4 experimental groups and one control (untreated). Experiments were performed in phases (Ph). Ph1: TAP (ciprofloxacin, metronidazole, minocycline), TAPM (ciprofloxacin, metronidazole, amoxicillin), DAP (ciprofloxacin, metronidazole), or CH treatment groups. After 1 and 3 days (d); 1, 2, 3 weeks (w); and 1, 2, 3 and 4 months (m), color was measured and medications were removed. Ph2: GIC or MTA cervical sealing, each using half of the specimens from each group. Color was assessed after 1d, 3d; 1w, 2w, 3w; 1m and 2m. Ph3: Two bleaching sessions, each followed by color measurement. Data were analyzed with ANOVA and post-hoc Holm-Sidak method. Results Ph1: Specimens of TAP group presented higher color alteration (ΔE) mean than those of TAPM group. No significant difference was found among TAP or TAPM and CH, DAP or Control groups. Ph2: cervical sealing materials showed no influence on color alteration. Ph3: Different ΔE means (from different groups), prior to bleaching, became equivalent after one bleaching session. Conclusions TAP induces higher color alteration than TAPM; color alteration increases over time; cervical sealing material has no influence on color alteration; and, dental bleaching was able to recover, at least partially, the tooth crown’s color

Effect of Milk Renewal on Cell Viability In Vitro at Different Time Frames

<div><p>Abstract The purpose of this study was to evaluate if the renewal of milk as a storage medium, every 12, 24 and 48 h, is able to increase its ability to maintain human periodontal ligament fibroblasts (PDLF) viability over time. PDLF were soaked in Minimum Essential Medium at 37 °C (MEM-37) (positive control), tap water (Water) (negative control) and in skimmed milk (44 wells) at 5 °C and 20 °C. The skimmed milk was renewed every 12 h (Milk-12), 24 h (Milk-24) and 48 h (Milk-48) in 11 wells of each plate, and the milk in the remaining 11 wells of each plate was maintained in situ (not renewed milk) (NRM). After 24, 48, 72, 96 and 120 h, cell viability was determined by the tetrazolium salt-based colorimetric (MTT) assay. Data were statistically analyzed by Kruskal-Wallis, Scheffé and Mann-Whitney tests (a=5%). At 5 °C, only Milk-48 was significantly better than NRM. At 20 °C, NRM was more effective than Milk-12 and Milk-24 in all time periods. In relation to the temperature (5 °C or 20 °C), renewal of milk at 5 °C was better in maintaining cell viability than the renewal at 20 °C. In conclusion, the renewal of milk was able to increase its ability to maintain cell viability only when performed every 48 h in milk maintained at 5 °C.</p></div