Introduction: The Atraumatic Restorative Treatment (ART) is based on the indirect pulp capping technique. In these techniques, the infected dentine is removed and a glass ionomer cement (GIC) restoration is placed on remnant demineralized dentine to allow remineralization to occur. There is some evidence from in vitro and in vivo studies that fluoride and strontium diffuse into demineralized dentine (Kitasako, Nakajima et al. 2003); Smales 2005; Ngo 2006), and may contribute to remineralization. However, it is proposed that the mineral ions diffusing from dentinal tubular fluid also contribute. Shellis (1994) and Ozok (2004) recently demonstrated that infused surrogated dentinal fluid could decrease the depth of demineralization in dentine under an acidic challenge. Objectives: This study aimed to investigate the role of Simulated Dentine Tubule Fluid (SDTF) in remineralization of the remnant demineralized dentine using an in vitro model of the ART technique. Material and method: An apparatus was developed to achieve fluid flow into the pulp chambers of molar crowns, and thus into the dentine tubules at the same hydrostatic pressure as operates in vivo. A pilot study was carried out which demonstrated that the dye can diffuse into the dentine tubules when both artificial and natural caries are present, thus validating the method. A further pilot study demonstrated that SDTF could reduce the level of calcium lost in dentine under an acidic challenge, which agreed with Shellis and Ozok’s findings. Moreover, in the presence of the SDTF, the remineralization of demineralized dentine increased with exposure to a remineralizing solution. The main experiment of this study was to investigate whether SDTF can enhance remineralization of demineralized dentine using an in vitro ART simulation method. In this experiment, Class 1 cavities of similar dimension were cut in 18 extracted, intact third molar teeth. These teeth were painted with nail varnish leaving the dentine floors exposed for generation of artificial caries (6 teeth each for 7 days, 14 days and 21 days of demineralization). Half of the demineralized cavity floor was protected with nail varnish providing a control and test side. The cavity was restored in Fuji IX which enabled a direct contact between demineralized dentine on the test half of the cavity floor and Fuji IX. A reservoir of SDTF was connected to supply SDTF under prescribed hydrostatic pressure to each pulp chamber for 21 days during which ion exchange was proceeding between GIC and demineralized dentine as demonstrated by Ngo (2005). Teeth were then detached from the system, sectioned and prepared for analysis by Electron Probe to determine profiles of Ca, P, F and Sr across the demineralized dentine under the GIC restoration. The results from this experiment, while showing an increase in calcium in the test over control side of the lesion, also showed an increase of calcium levels on both test and control side. This suggested a need to modify the model to provide evidence of the increase in calcium and other elements above the baseline profiles originally present in the demineralized dentine. The modified model was developed which sectioned the teeth into halves. Each half of the tooth was treated as an individual sample in separated experiments where one was supplied with SDTF and the other with De-ionized Distilled Water. Based on the assumption that the mineral contents in two halves of the same tooth initially were similar, any increase in mineral contents in either half of the tooth could be considered as an indication of remineralization. Other experiments were carried out to investigate the interaction between the SDTF to calcium rich materials which were applied to the demineralized dentine, and to investigate the effect of longer exposure time on remineralization. In the first experiment, Ketac Molar was used as an alternative restorative material which is calcium based restorative material. In the second experiment, CPP-ACP was applied to the demineralized dentine before placement of composite resin or glass ionomer cement restorations. In the third experiment, the exposure time of demineralized dentine under Fuji IX restoration to SDTF was increased to six weeks to look at the effect of longer periods of exposure to SDTF on overall remineralization. Results: Both the initial and enhanced models showed the effectiveness of SDTF on remineralization in vitro under GIC restorations. The results provided evidence of an initial positive equilibrium gradient between SDTF and demineralized dentine. The placement of a GIC restoration provided an added gradient in terms of calcium concentration between SDTF and the adjacent GIC restoration. If the calcium level in the restoration was higher than that in the SDTF, as occurred with Ketac Molar, the diffusion of calcium into demineralized dentine was diminished. This also occurred in the presence of CPP-ACP. In the presence of CPPACP, the calcium/phosphorus ratios in the demineralized dentine (adjacent to the restoration) was reduced and nearer to the ratio in calcium deficient apatite. However, the longer exposure time of the demineralized dentine to GIC restoration in the presence of the SDTF increased remineralization. Conclusion: Dentinal tubule fluid contributes significantly to remineralization of the partially demineralized dentine in this model of the ART technique. However, the level of remineralization is very sensitive to factors affecting the concentration gradients between critical structural elements with the SDTF and the restoration. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1325244 / Thesis (Ph.D.) -- University of Adelaide, School of Dentistry, 2008

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / There is a general consensus that resin-dentin bonds created by contemporary hydrophilic dentin adhesives deteriorate over time. One way to predict how resin-dentin interface would behave over time is aging the specimens in vitro by immersion in different solutions. The objective of this study was to evaluate the effect of immersion in NaOCl solution on the bond interface created by different adhesive systems. For this, it was used 28 human third molars that had superficial dentin exposed and composite build-ups were built on its surface using one of those adhesives, etch-and-rinse: Scothbond Multi-purpose and Single Bond, or self-etch: Clearfil SE and Adper SE. Specimens were cut into nontrimming dentin-composite beams to microtensile testing. After a period of 24 h in distilled water, sticks from each tooth were divided equally into two groups: control or aged in 10% NaOCl for 1 h. Beams were pulled until failure at crosshead speed of 1 mm/min and bond strength was calculated. Fractured sticks were analyzed and classified in: mixed fracture, cohesive in dentin and cohesive in composite; and expressed in percentage. Data from ÂTBS test were statistically analyzed using Kruskal-Wallis and Games-Howell tests. For comparison between control and aging groups was used the Mann-Whitney test (α=0.05). Two specimens from each adhesive were used to investigate the effect of NaOCl on the interfacial morphological characteristics. For that, specimens were cut in only one direction, dentin-resin discs were fixed in a glass-holder and ground with SiC papers under running water. Slices were treated by Massonâs trichrome acid staining technique to evidence collagen exposed zones and analyzed by optical microscopy. ÂTBS results showed that NaOCl solution significantly reduced bond strength comparing with the control groups for all adhesives tested. Scothbond MP (control: 39,95Â12,72; aged: 26,45Â9,90 MPa) showed the highest values and Adper SE (control: 13,21Â3,15; aged 4,95Â2,49) the lowest in both control and aging groups. Clearfil SE (control : 27,02Â6,84; aged: 16,17Â3,79) and Single Bond (control : 26,66Â8,35; aged: 11,77Â4,28) showed no difference in control groups, but after aging, Clearfil SE showed better results. Microscopic images analysis showed that NaOCl acts efficiently on degradation of collagen fibrils for all adhesive systems. Conclusion: Aging in 10% NaOCl solution reduces bond strength and modifies the interfacial morphological characteristics of the adhesive systems tested. / Hà um consenso geral de que a uniÃo resina-dentina criada pelos adesivos dentinÃrios hidrofÃlicos contemporÃneos se deterioram com o tempo. Uma maneira de prever o comportamento da interface adesiva ao longo do tempo à atravÃs do envelhecimento in vitro por imersÃo em diferentes soluÃÃes. O objetivo deste trabalho foi avaliar o efeito da imersÃo em soluÃÃo de NaOCl na interface de uniÃo criada por diferentes sistemas adesivos. Para isso, foram usados 28 terceiros molares humanos que tiveram a dentina coronÃria exposta e um platà de resina composta confeccionado sobre sua superfÃcie apÃs a aplicaÃÃo de um dos seguintes sistemas adesivos, condicionamento total: Scothbond Multi-uso e Single Bond, ou autocondicionantes: Clearfil SE e Adper SE. Os espÃcimes foram cortados pela tÃcnica nontrimming de obtenÃÃo de palitos para o teste de microtraÃÃo. ApÃs um perÃodo de 24 horas em Ãgua destilada, os palitos de cada dente foram igualmente divididos em dois grupos: controle ou envelhecido em soluÃÃo de NaOCl a 10% por 1 hora. Os espÃcimes foram tracionados atà a ruptura da uniÃo a uma velocidade de 1 mm/min e sua forÃa de uniÃo mensurada. Os palitos fraturados foram analisados e classificados em: fratura mista, coesiva em dentina e coesiva em compÃsito, e os valores expressos em porcentagem. Os dados da resistÃncia de uniÃo foram estatisticamente analisados usando os testes Kruskal-Wallis e Games-Howell. Para comparaÃÃo entre os grupos controle e envelhecido foi usado o teste de Mann-Whitney (α=0.05). Dois espÃcimes de cada adesivo foram usados para investigar o efeito do NaOCl nas caracterÃsticas morfolÃgicas da interface de uniÃo. Para isso, espÃcimes foram cortados ao longo eixo em apenas uma direÃÃo e os discos de dentina-resina foram fixados em lÃmina de vidro e desgastados com lixas de SiC sob refrigeraÃÃo com Ãgua. As lÃminas foram tratadas pela tÃcnica de coloraÃÃo Ãcida de Masson para evidenciar as zonas de colÃgeno exposto e observadas atravÃs de microscopia Ãptica. Os resultados do teste de microtraÃÃo mostraram que a soluÃÃo de NaOCl reduziu significativamente a forÃa de uniÃo em comparaÃÃo aos grupos controle para todos os adesivos testados. Scothbond MU (controle: 39,95Â12,72; envelhecido: 26,45Â9,90 MPa) mostrou os maiores valores de uniÃo e Adper SE (controle: 13,21Â3,15; envelhecido 4,95Â2,49) os menores valores, tanto para o grupo controle quanto envelhecido. Clearfil SE (controle: 27,02Â6,84; envelhecido: 16,17Â3,79) e Single Bond (controle: 26,66Â8,35; envelhecido: 11,77Â4,28) nÃo mostraram diferenÃa estatÃstica nos grupos controle, mas apÃs envelhecimento, Clearfil SE mostrou melhores resultados. A anÃlise das imagens microscÃpicas mostrou que o NaOCl agiu efetivamente na degradaÃÃo das fibras de colÃgeno para todos os sistemas adesivos testados. ConclusÃo: O envelhecimento dos espÃcimes em soluÃÃo de NaOCl a 10% reduziu a resistÃncia de uniÃo e modificou as caracterÃsticas morfolÃgicas da interface adesiva para os sistemas adesivos testados.

Calcium phosphate spheres as biomaterials have been attracting attention in recent years. Calcium phosphate occurs naturally in bone, and a hollow structure could be advantageous for drug loading and release. The combination of a calcium phosphate chemistry and a spherical-hollow structure could be an optimal strategy for specific biomaterial applications, e.g., certain dental and drug-delivery applications. The focus of this thesis is on the synthesis, formation mechanism and applications of hollow, spherical calcium phosphate particles. First, the thesis describes two methods for the synthesis of calcium phosphate (CaP) spherical particles. The first method involves synthesis of hollow calcium phosphate spherical particles via a supersaturated buffer solution based on a previous study. It was utilised to prepare spheres for applications in drug delivery and dentistry. The second method was developed to explain the mechanism of formation of hollow calcium phosphate spheres. It aimed at revealing the particular function of magnesium in the formation of spherical particles. With the use of this modified method, it could be concluded that the only ions active in the formation of CaP spherical particles are calcium ions, phosphate ions and magnesium ions. Compared with the thermodynamics of micellisation, a new model, called three ions virtual micelle effect, was developed to explain the mechanism of the Mg function. Following this mechanism, a series of spherical particles of other compositions were explored. These spherical particles included strontium phosphate, barium phosphate, calcium fluoride, strontium fluoride and barium fluoride. In this thesis, CaP spheres were studied for the controlled delivery of active ingredients and as active agent for tooth remineralisation. The first investigated application was to control the release of vancomycin from Poly(methyl methacrylate) (PMMA) cement via strontium-doped CaP spheres (SCPS). The results showed that incorporation of CaP spheres into PMMA could enhance antibiotic release while maintaining the mechanical strength. The second application was to control hydrogen peroxide (HP) release from two bleaching gel, in which CP-loaded CaP spheres were the active ingredient. One gel with low HP concentration was developed as an at-home bleaching gel, and one with high HP concentration was developed as an in-office bleaching gel. The results showed that CaP spheres would give a controlled release of peroxide and thus have a potential to increase the efficacy of the bleaching. The third application was to investigate the potential for an anti-sensitivity effect of the spheres, as active agents in toothpaste. We studied the tooth tubules occlusion and the remineralisation effect of CaP spheres. After 7 days of application, the open dentin tubules and surface were fully covered by a newly formed apatite layer, demonstrating the remineralisation potential of the spheres.

The purpose of this study was to compare the antimicrobial effect of MTAD, two of its components, doxycycline and citric acid, and NaOCl on E. faecalis in two in vitro models: the bovine tooth model and the agar diffusion model. In the tooth model, the lumens of thirty bovine dentin discs were standardized, autoclaved and infected with E. faecalis for 14 days. The infected dentin discs were treated with either MTAD, doxycycline 100mg/ml, 10% citric acid, 5.25% NaOCl or saline for 10 minutes. Dentinal shavings were collected using sterile 037 and 040 round burs. The number of bacteria in the shavings was enumerated by overnight CO2 culturing on TSA agar plates. For the agar diffusion model, E. faecalis was plated before placing paper discs wetted with three dilutions of each irrigant. The zone of inhibition was recorded after overnight culture. The data were analyzed with a two-way ANOVA and Tukey-Kramer post-hoc test. In the bovine tooth model, NaOCl and doxycycline were more effective than control in killing E. faecalis at the shallow bur depth but at the deeper bur depth, only NaOCl was significantly more effective (psE. faecalis.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Os sistemas adesivos atuais apresentam resultados satisfatÃrios no que concerne à adesÃo ao esmalte e à dentina, entretanto, a maior causa de falhas em restauraÃÃes estÃticas ainda à a ocorrÃncia de recidiva de cÃrie ao longo de suas margens. Desta forma, este estudo avaliou a aÃÃo de sistemas adesivos com flÃor e/ou com um novo monÃmero, brometo de metacriloiloxidodecilpiridinio (MDPB) na composiÃÃo microbiolÃgica do biofilme dental e no processo de desmineralizaÃÃo do esmalte adjacente à restauraÃÃo de resina composta, mediante um delineamento in situ, cruzado e duplo-cego. Durante duas fases de 14 dias, dez voluntÃrios utilizaram dispositivos palatinos, contendo, cada um, quatro blocos de esmalte dental humano, restaurados extra-oralmente com resina composta Z250 e um dos seguintes sistemas adesivos: Adperâ Single Bond 2 (condicionamento total, G1), All-Bond SEâ (autocondicionante, G2), One-Up Bond F Plus (autocondicionante com flÃor, G3) e Clearfil Protect Bond (autocondicionante com flÃor e MDPB, G4). Os voluntÃrios foram aleatoriamente divididos entre os grupos, sendo que os que receberam os sistemas adesivos referentes aos grupos G1 e G2, na 1 fase, receberam os tratamentos referentes aos grupos G3 e G4 na 2 fase e vice-versa. Todos os voluntÃrios foram instruÃdos a gotejar sobre os blocos, oito vezes por dia, uma soluÃÃo de sacarose a 20%, simulando um desafio cariogÃnico, e a utilizar um dentifrÃcio fluoretado padronizado trÃs vezes por dia na higienizaÃÃo dentÃria. ApÃs o tÃrmino de cada fase o biofilme formado sobre cada bloco foi coletado e utilizado para a contagem de estreptococos totais, estreptococos mutans e lactobacilos. A perda de mineral foi analisada por meio do teste de microdureza em corte longitudinal do esmalte adjacente à restauraÃÃo. Aplicou-se a anÃlise de variÃncia, ANOVA, nÃo sendo observada diferenÃa estatisticamente significante para a composiÃÃo microbiolÃgica ou desmineralizaÃÃo do esmalte entre os adesivos estudados. Concluiu-se que a incorporaÃÃo de MDPB e/ou flÃor nos sistemas adesivos autocondicionantes nÃo foi capaz, nas condiÃÃes deste estudo, de prevenir a ocorrÃncia da cÃrie secundÃria. / Contemporary adhesives systems present satisfactory bonding to enamel and dentin. However, replacement of the restorations due to secondary caries formation is still a major problem and of great concern in Dentistry. Thus, this study assessed in situ the effects of adhesive systems containing or not fluoride and/or the antibacterial monomer 12-methacryloyloxydodecylpyridinium bromide (MDPB) on the microbiological composition of dental biofilm and on enamel demineralization. During two phases of 14 days each, ten volunteers wore palatal appliances containing four human enamel slabs, which were extra-orally restored using a resin composite (Z250 3M-ESPE) and one of the following adhesive systems: Adperâ Single Bond 2 (total etch, G1); All-Bond SEâ (self-etch, G2); One-Up Bond F Plus (self-etch containing fluoride G3) and Clearfil Protect Bond (self-etch containing fluoride and MDPB, G4). The volunteers were randomly allocated to treatments, and those who received G1 and G2 in the first phase received G3 and G4 in the second one, and vice versa. The volunteers were asked to drop a 20% sucrose solution onto the slabs eight times per day and to use fluoridated dentifrice 3 times per day. The biofilm formed on the slabs was analyzed with regard to total and mutans streptococci as well as lactobacilli counts. Demineralization was determined on enamel around the restorations by cross-sectional microhardness. The data were analyzed by analysis of variance, ANOVA. No differences were found for microbiological composition or enamel demineralization among the studied adhesive systems. It can be concluded that that fluoride or MDPB addition to adhesives systems presented no effect in controlling caries around resin restorations in this in situ model.

O objetivo do presente estudo foi avaliar a remoção da smear layer e a penetração intratubular do cimento obturador AH Plus utilizando diferentes protocolos de irrigação. Após aprovação do Comitê de Ética em Pesquisa da Faculdade de Odontologia de Ribeirão Preto - FORP/USP, noventa incisivos centrais superiores foram selecionados e fornecidos pelo banco de dentes da mesma instituição. Estes foram radiografados no sentido mésio - distal e vestíbulo - lingual para comprovar a presença de canais únicos, sem curvaturas abruptas, reabsorções ou tratamentos endodônticos prévios. Após a remoção da porção coronal para a obtenção de raízes com comprimentos padronizados de 15 milímetros, os diâmetros anatômicos foram determinados e as instrumentações realizadas por meio da técnica coroa ápice estabelecendo os diâmetros cirúrgicos utilizando 3 instrumentos acima dos anatômicos. Durante este processo, os espécimes foram divididos em seis grupos de acordo com os protocolos de irrigação: Grupo 1 (controle - n. 15) - 2,5ml de água destilada a cada troca de instrumentos e 2,5ml de água destilada por 3 minutos ao final da instrumentação; Grupo 2 (n. 15) - 2,5ml de hipoclorito de sódio a 2,5% a cada troca de instrumentos e 2,5ml de hipoclorito de sódio a 2,5% por 3 minutos ao final da instrumentação; Grupo 3 (n. 15) - 2,5ml de hipoclorito de sódio a 2,5% a cada troca de instrumentos e 2,5ml de EDTA a 17% por 3 minutos ao final da instrumentação; Grupo 4 (n. 15) - 2,5ml de hipoclorito de sódio a 2,5% e 2,5ml de EDTA a 17% a cada troca de instrumentos + 2,5ml de EDTA a 17% por 3 minutos ao final da instrumentação; Grupo 5 (n. 15) - 2,5ml de hipoclorito de sódio a 2,5% a cada troca de instrumentos e 2,5ml de ácido cítrico a 10% por 3 minutos ao final da instrumentação; Grupo 6 (n. 15) - 2,5ml de hipoclorito de sódio a 2,5% e 2,5ml de ácido cítrico a 10% a cada troca de instrumentos + 2,5ml de ácido cítrico a 10% por 3 minutos ao final da instrumentação. Após esta fase, cinco espécimes de cada grupo foram clivados no sentido mésio - distal para avaliação da remoção da smear layer em microscopia eletrônica de varredura por meio da análise de 3 imagens de cada terço em aumentos de 300, 1000 e 2000 vezes. Esta variável foi determinada por um score qualitativo estabelecido pelo consenso de 3 avaliadores calibrados. Os demais espécimes foram obturados pela técnica de condensação lateral com cones principais correspondentes ao último instrumento associados ao cimento AH Plus corado com Rodamina B, cones acessórios B8 e mantidos em ambiente com 100% de umidade por 7 dias. Em seguida, os espécimes foram seccionados transversalmente para obtenção de slices de aproximadamente 2mm de espessura em cada terço (cervical, médio e apical) e as faces cervicais submetidas a um tratamento metalográfico para análise da penetração intratubular do cimento obturador em microscopia confocal a laser. Os melhores índices de remoção de smear layer e as maiores porcentagens de penetração intratubular do cimento foram obtidos pelos grupos onde as soluções quelantes foram utilizadas (G3, G4, G5 e G6) com diferenças estatisticamente significantes (p<0,05) em relação aos grupos onde utilizou - se somente a água destilada (G1) e o hipoclorito de sódio a 2,5% (G2) durante o processo de instrumentação. Não foram observadas vantagens em relação ao uso associado do EDTA a 17% e do ácido cítrico a 10% ao hipoclorito de sódio pela ausência de diferenças estatísticas significantes entre os grupos 3 e 4 e 5 e 6, respectivamente. / The aim of this study was to evaluate the smear layer removal and tubular dentine sealer penetration of AH Plus after different irrigation protocols. After approval of the study by the Ethics Committee of the Ribeirão Preto Dental School - FORP/USP, ninety maxillary central incisors were selected and supplied by the tooth bank of the same institution. The teeth were radiographed in the mesiodistal and buccolingual directions to verify the presence of single canals, without abrupt curvatures, resorption or previous endodontic treatment. The coronal portion was removed and roots lengths were standardized at 15 mm. The anatomic diameters were then determined and instrumentations were carried out by the crown-down technique, using 3 higher-diameter instruments to establish the surgical diameters. During this process, the specimens were divided into six groups, according to the following irrigation protocols: Group 1 (control - n. 15) - 2.5ml of distilled water at each change of instruments + 2.5ml of distilled water for 3 minutes at the end of the instrumentation; Group 2 (n. 15) - 2.5ml of 2.5% sodium hypochlorite at each change of instruments + 2.5 ml of 2.5% sodium hypochlorite for 3 minutes at the end of the instrumentation; Group 3 (n. 15) - 2.5ml of 2.5% sodium hypochlorite at each change of instruments + 2.5ml of 17% EDTA for 3 minutes at the end of the instrumentation; Group 4 (n. 15) - 2.5ml of 2.5% sodium hypochlorite and 2.5ml of 17% EDTA at each change of instruments + 2.5ml of 17% EDTA for 3 minutes at the end of the instrumentation; Group 5 (n. 15) - 2.5ml of 2.5% sodium hypochlorite at each change of instruments + 2.5ml of 10% citric acid for 3 minutes at the end of the instrumentation; Group 6 (n. 15) - 2.5ml of 2.5% sodium hypochlorite and 2.5 ml of 10% citric acid at each change of instruments + 2.5 ml of 10% citric acid for 3 minutes at the end of the instrumentation. Following this phase, five specimens from each group were cleaved in the mesiodistal direction to evaluate the smear layer removal by scanning electron microscopy. Evaluation was performed by analyzing 3 images of each third at 300, 1000 and 2000X. This variable was determined by a qualitative score established by the consensus of 3 calibrated examiners. The remaining specimens were filled using lateral condensation with AH Plus sealer labeled with Rhodamine B and kept in an environment with 100% humidity for 7 days. Then, the specimens were sectioned to obtain approximately 2 mm thick slices of each third (cervical, middle and apical). The cervical surfaces were subjected to metallographic treatment for analysis of the tubular dentine sealer penetration by confocal laser microscopy. The highest smear layer removal rates and tubular dentine sealer penetration percentages were obtained by the groups that used chelating solutions (G3, G4, G5 and G6). These showed statistically significant differences (p<0.05) compared with the groups that used just distilled water (G1) and 2.5% sodium hypochlorite (G2) during instrumentation. No benefits were observed for the combined use of 17% EDTA or 10% citric acid with 2.5% sodium hypochlorite, considering that there were no statistically significant differences between groups 3 and 4, and between 5 and 6, respectively.

The present research had the objective to analyze qualitatively though histobacteriology, the remaining dentine of upper human premolars after removal of clinically decayed tissue, according to presence, location and distribution of microorganisms in dental tubules in different degrees of depth of carious lesion. It was selected representative histological blades of histological cut in series, obtained during the research of Biffi et al (1982), extracted from patients of both genera and age from 20 to 40 years old. The teeth should present proximal caries and/ or occlusal caries and the removal of decayed tissue would be done in vitro. The three faces (dental, mesial and occusal) were clinically classified according to the depth of the caries in degrees 0, 1, 2, 3, 4 or 5 and microscopically assessed. The blades were tinged using the technique of Hematoxylin and Eosine, Trichrome of Masson and histobacteriological of Gram, modified by Brown and Brenn. The interpretation of histological cuts was realized with the use of a trinocular and photomicroscope. In the descriptive analysis it was possible to check the bacterial penetration in a superficial way and/ or in a deep way in the dentinal tubules both in the pulpal floor or in the amelodentinal junction, as well as the presence of bacterial niches in the cavity preparation. The contaminated tubules showed morphologically inaltered, and in pulp exposure during the removal of deep caries it was verified the introduction of a contaminated dentinal fragment in the pulp tissue. In order to have a statistical analysis of the number of microorganisms, it was applied the Pearson s correlation coefficient, respectively among the different degrees of caries and localization in the amelodentinal junction and pulp floor. It was brought to a conclusion that, in 56,7% of the decayed faces the microorganisms were placed in dentine considered clinically healthy, in which they lodged in dentinal tubules morphologically inaltered; the localization and the distribution of microorganisms in the tubules were variable and independent of the depth of the caries. / A presente pesquisa teve como objetivo realizar analise histobacteriológica da dentina remanescente de pré-molares humanos após a remoção do tecido cariado, quanto à presença, localização e distribuição dos microrganismos nos túbulos dentinários em diferentes graus de profundidade da lesão cariosa. Foram selecionadas lâminas histológicas representativas de cortes histológicos seriados de 20 dentes, obtidos durante a pesquisa de Biffi et al. (1982), extraídos de pacientes de ambos os gêneros e faixa etária entre 20 a 40 anos. Estes dentes apresentaram cárie proximal e/ou oclusal e a remoção do tecido cariado foi realizada in vitro. As três faces do dente (mesial, distal e oclusal) foram clinicamente classificadas quanto à profundidade de cárie em graus 0, 1, 2, 3, 4 ou 5 e microscopicamente avaliadas. As lâminas foram coradas pela técnica Hematoxilina e Eosina, Tricrômico de Masson e histobacteriológico de Gram, modificado por Brown e Brenn. A analise dos cortes histológicos foi realizada utilizando o microscópio de luz. Na análise histológica foi observada a presença bacteriana superficial e/ou profunda nos túbulos dentinários tanto no assoalho pulpar quanto na junção amelo-dentinária, bem como a presença de nichos bacterianos no preparo cavitário. Os túbulos contaminados apresentavam-se morfologicamente inalterados e na exposição pulpar, durante a remoção profunda da cárie, constatou-se a introdução de fragmento dentinário contaminado no tecido pulpar. Para análise estatística do número de microrganismos, foi aplicado o coeficiente de correlação de Pearson, respectivamente entre os diferentes graus de cárie e localização na junção amelo-dentinária e assoalho pulpar. Conclui-se que, em 56,7% das faces cariadas os microrganismos encontravam-se situados na dentina considerada clinicamente como sadia, os quais alojavam-se em túbulos dentinários morfologicamente inalterados; a localização e a distribuição dos microrganismos nos túbulos foi variável e independente da profundidade da cárie. / Mestre em Odontologia

A radiopacidade dos materiais restauradores deve permitir distinguí-los da estrutura dental. Os adesivos dentinários normalmente, não possuem radiopacidade satisfatória a qual pode ser buscada com o acréscimo de substâncias que apresentem essa característica. Entretanto, esses materiais não devem interferir negativamente nas propriedades do polímero formado. O objetivo deste estudo foi avaliar a influência da adição de substâncias radiopacificantes em uma resina adesiva experimental nas propriedades do polímero. Uma resina adesiva experimental foi formulada com 50 % de Bis- GMA, 25 % TEGDMA, e 25 % HEMA, em peso, acrescido de Canforoquinona e EDAB (1% /mol). Para formar os grupos experimentais seis substâncias foram adicionadas à resina base: dióxido de titânio, óxido de bismuto, sulfato de bário, quartzo, dióxido de zircônio e trifluoreto de itérbio, em diferentes concentrações. A radiopacidade foi avaliada utilizando um sistema digital com placas de fósforo VistaScan (Dürr Dental GmbH & CO. KG, Bietigheim- Bissingen, Alemanha) sendo analisadas através do software DBSWIN 4.5, quanto a densidade radiográfica. As demais propriedades avaliadas foram: grau de conversão através de FTIR; resistência à flexão, baseada na normatização da ISO 4049/2010. Radiopacidade de resinas adesivas experimentais com ao menos 30% sulfato de bário ou óxido de bismuto ou 40% de zircônia apresentaram radiopacidade semelhante a 2mm de alumínio. Resinas adesivas com ao menos 20% de fluoreto de itérbio apresentaram radiopacidade satisfatória (2mm de Al) sem influenciar outras propriedades. / The radiopacity of restorative materials should be sufficient to allow the clinician to distinguish the material from normal and demineralized tissues. It is recognized that unfilled resin adhesives are radiolucent which could be reached with radiopaquing agents’ addition. The aim of this study is to evaluate, in an experimental adhesive resin, the influence of radiopaquing agents at polymer properties. A model adhesive resin was formulated with 50% of Bis-GMA, 25% of TEGDMA, 25% of HEMA in weight, and camphorquinone and EDAB (1%mol). The experimental groups were formed with addition of six radiopaquing agents: titanium dioxide, bismuth oxide, barium sulfate, quartz, zirconium, and ytterbium trifluoride at different concentration. The radiopacity was evaluated using an aluminum step-wedge and VistaScan (Dürr Dental GmbH & CO. KG, Bietigheim-Bissingen, Alemanha) phosphorous plates radiographs digital system and DBSWIN 4.5 software. The other properties evaluated were degree of conversion with FTIR and flexural strength, based at ISO 4049/2010. Radiopacity of model adhesive resins with at least 30% of barium sulfate or bismuth oxide or 40% of zircon showed no significant differences to 2mm of aluminum. Adhesive resin with at least 20% addition of ytterbium trifluoride presented satisfactory radiopacity (Al 2mm) without influencing other properties.

O objetivo do presente estudo foi avaliar a remoção da smear layer e a penetração intratubular do cimento obturador AH Plus utilizando diferentes protocolos de irrigação. Após aprovação do Comitê de Ética em Pesquisa da Faculdade de Odontologia de Ribeirão Preto - FORP/USP, noventa incisivos centrais superiores foram selecionados e fornecidos pelo banco de dentes da mesma instituição. Estes foram radiografados no sentido mésio - distal e vestíbulo - lingual para comprovar a presença de canais únicos, sem curvaturas abruptas, reabsorções ou tratamentos endodônticos prévios. Após a remoção da porção coronal para a obtenção de raízes com comprimentos padronizados de 15 milímetros, os diâmetros anatômicos foram determinados e as instrumentações realizadas por meio da técnica coroa ápice estabelecendo os diâmetros cirúrgicos utilizando 3 instrumentos acima dos anatômicos. Durante este processo, os espécimes foram divididos em seis grupos de acordo com os protocolos de irrigação: Grupo 1 (controle - n. 15) - 2,5ml de água destilada a cada troca de instrumentos e 2,5ml de água destilada por 3 minutos ao final da instrumentação; Grupo 2 (n. 15) - 2,5ml de hipoclorito de sódio a 2,5% a cada troca de instrumentos e 2,5ml de hipoclorito de sódio a 2,5% por 3 minutos ao final da instrumentação; Grupo 3 (n. 15) - 2,5ml de hipoclorito de sódio a 2,5% a cada troca de instrumentos e 2,5ml de EDTA a 17% por 3 minutos ao final da instrumentação; Grupo 4 (n. 15) - 2,5ml de hipoclorito de sódio a 2,5% e 2,5ml de EDTA a 17% a cada troca de instrumentos + 2,5ml de EDTA a 17% por 3 minutos ao final da instrumentação; Grupo 5 (n. 15) - 2,5ml de hipoclorito de sódio a 2,5% a cada troca de instrumentos e 2,5ml de ácido cítrico a 10% por 3 minutos ao final da instrumentação; Grupo 6 (n. 15) - 2,5ml de hipoclorito de sódio a 2,5% e 2,5ml de ácido cítrico a 10% a cada troca de instrumentos + 2,5ml de ácido cítrico a 10% por 3 minutos ao final da instrumentação. Após esta fase, cinco espécimes de cada grupo foram clivados no sentido mésio - distal para avaliação da remoção da smear layer em microscopia eletrônica de varredura por meio da análise de 3 imagens de cada terço em aumentos de 300, 1000 e 2000 vezes. Esta variável foi determinada por um score qualitativo estabelecido pelo consenso de 3 avaliadores calibrados. Os demais espécimes foram obturados pela técnica de condensação lateral com cones principais correspondentes ao último instrumento associados ao cimento AH Plus corado com Rodamina B, cones acessórios B8 e mantidos em ambiente com 100% de umidade por 7 dias. Em seguida, os espécimes foram seccionados transversalmente para obtenção de slices de aproximadamente 2mm de espessura em cada terço (cervical, médio e apical) e as faces cervicais submetidas a um tratamento metalográfico para análise da penetração intratubular do cimento obturador em microscopia confocal a laser. Os melhores índices de remoção de smear layer e as maiores porcentagens de penetração intratubular do cimento foram obtidos pelos grupos onde as soluções quelantes foram utilizadas (G3, G4, G5 e G6) com diferenças estatisticamente significantes (p<0,05) em relação aos grupos onde utilizou - se somente a água destilada (G1) e o hipoclorito de sódio a 2,5% (G2) durante o processo de instrumentação. Não foram observadas vantagens em relação ao uso associado do EDTA a 17% e do ácido cítrico a 10% ao hipoclorito de sódio pela ausência de diferenças estatísticas significantes entre os grupos 3 e 4 e 5 e 6, respectivamente. / The aim of this study was to evaluate the smear layer removal and tubular dentine sealer penetration of AH Plus after different irrigation protocols. After approval of the study by the Ethics Committee of the Ribeirão Preto Dental School - FORP/USP, ninety maxillary central incisors were selected and supplied by the tooth bank of the same institution. The teeth were radiographed in the mesiodistal and buccolingual directions to verify the presence of single canals, without abrupt curvatures, resorption or previous endodontic treatment. The coronal portion was removed and roots lengths were standardized at 15 mm. The anatomic diameters were then determined and instrumentations were carried out by the crown-down technique, using 3 higher-diameter instruments to establish the surgical diameters. During this process, the specimens were divided into six groups, according to the following irrigation protocols: Group 1 (control - n. 15) - 2.5ml of distilled water at each change of instruments + 2.5ml of distilled water for 3 minutes at the end of the instrumentation; Group 2 (n. 15) - 2.5ml of 2.5% sodium hypochlorite at each change of instruments + 2.5 ml of 2.5% sodium hypochlorite for 3 minutes at the end of the instrumentation; Group 3 (n. 15) - 2.5ml of 2.5% sodium hypochlorite at each change of instruments + 2.5ml of 17% EDTA for 3 minutes at the end of the instrumentation; Group 4 (n. 15) - 2.5ml of 2.5% sodium hypochlorite and 2.5ml of 17% EDTA at each change of instruments + 2.5ml of 17% EDTA for 3 minutes at the end of the instrumentation; Group 5 (n. 15) - 2.5ml of 2.5% sodium hypochlorite at each change of instruments + 2.5ml of 10% citric acid for 3 minutes at the end of the instrumentation; Group 6 (n. 15) - 2.5ml of 2.5% sodium hypochlorite and 2.5 ml of 10% citric acid at each change of instruments + 2.5 ml of 10% citric acid for 3 minutes at the end of the instrumentation. Following this phase, five specimens from each group were cleaved in the mesiodistal direction to evaluate the smear layer removal by scanning electron microscopy. Evaluation was performed by analyzing 3 images of each third at 300, 1000 and 2000X. This variable was determined by a qualitative score established by the consensus of 3 calibrated examiners. The remaining specimens were filled using lateral condensation with AH Plus sealer labeled with Rhodamine B and kept in an environment with 100% humidity for 7 days. Then, the specimens were sectioned to obtain approximately 2 mm thick slices of each third (cervical, middle and apical). The cervical surfaces were subjected to metallographic treatment for analysis of the tubular dentine sealer penetration by confocal laser microscopy. The highest smear layer removal rates and tubular dentine sealer penetration percentages were obtained by the groups that used chelating solutions (G3, G4, G5 and G6). These showed statistically significant differences (p<0.05) compared with the groups that used just distilled water (G1) and 2.5% sodium hypochlorite (G2) during instrumentation. No benefits were observed for the combined use of 17% EDTA or 10% citric acid with 2.5% sodium hypochlorite, considering that there were no statistically significant differences between groups 3 and 4, and between 5 and 6, respectively.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Dentinal defects are characterized by cracks in the root dentin that can develop into a vertical root fractures (VRF), thus leading to tooth loss. Endodontic procedures may generate these defects and between these steps, the biomechanical preparations with NiTi rotary instruments are associated with the incidence of these amendments dentinal. A new concept in minimally invasive preparation was introduced, along with a new reciprocating movement, using a single instrument for root canal instrumentation. This allows less root dentin is removed, thus avoiding the weakening of tooth structure. The aim of this study was evaluate the incidence of dentinal defects after root canal preparation by three single-file systems. One hundred forty mesial roots of mandibular molars were selected and randomly assigned to 4 groups (n= 35 mesial roots per group). One group was left unprepared as control. In two groups, the root canals were instrumented by using the reciprocating single-file systems WaveOne (Dentsply-Maillefer) and Reciproc (VDW), while other group was prepared with single-file of continuous rotation One Shape (Micro-Mega). The specimens were sectioned in 03, 06 and 09 mm from the apex with a low-speed saw under water cooling (IsoMet 1000 Precision Saw) and observed through a stereomicroscope (Zeiss Stemi SV6, Carl Zeiss) at a magnification of 20×. The pictures were recorded and evaluated by two blinded calibrated observers. The slices were categorized in: 0- No defects; 1- Others defects and 2 vertical root fracture. The dates were statistically analyzed with a significance level set at α = 0.05. The chi-square and Fisher exact tests were used to assess the differences between groups. No defects were observed in control group. All the experimental groups showed dentinal defects. The reciprocating files were associated with more defects than the continuous rotary file and control group (P < 0.05), but no significant difference between them (P = .115). VRF was observed only in the One Shape group. The results of this study suggest that the biomechanical preparation could cause damage in the root dentin and that the continuous rotary has a tendency to result in fewer defects compared to reciprocating files. / Defeitos dentinários são caracterizados por trincas na dentina radicular que podem evoluir para uma Fratura Vertical da Raiz (FVR), levando assim a perda do elemento dentário. O preparo biomecânico com o uso de sistemas rotatórios está associado com a incidência dessas alterações dentinárias. Atualmente, o uso de um único instrumento para a instrumentação dos canais radiculares juntamente com uma cinemática reciprocante tem sido introduzido. Desse modo, o objetivo desse estudo foi avaliar a incidência de defeitos dentinários causado por três sistemas de instrumento único. Cento e quarenta raízes mesiais de molares inferiores foram selecionadas e aleatoriamente divididas em quatro grupos (n= 35 por grupo). Um grupo não sofreu intervenção e serviu como controle. As demais raízes foram preparadas pelos instrumentos reciprocantes WaveOne (Dentsply-Maillefer) e Reciproc (VDW) e por um instrumento de rotação contínua One Shape (Micro-Mega). As raízes foram seccionadas horizontalmente com auxílio de uma máquina de corte de precisão (IsoMet 1000 Precision Saw) em 03, 06 e 09 mm a partir do ápice e observadas em um estereomicroscópio (Zeiss Stemi SV6, Carl Zeiss) sob um aumento de 20×. Imagens das fatias foram gravadas e avaliadas por dois observadores cegos, previamente calibrados. As fatias foram categorizadas em: 0 - Ausência de defeitos; 1- Outros defeitos; 2- Fratura Vertical da Raiz. Os resultados obtidos foram submetidos à análise estatística com nível de significância fixado em α= 0.05. Os testes Qui-quadrado e Exato de Fisher foram utilizados para analisar e comparar as diferenças entre os grupos. O grupo controle não apresentou defeito. Todos os grupos experimentais apresentaram defeitos dentinários e foram diferentes estatisticamente do grupo controle (P < 0.05). Os grupos reciprocantes foram associados à presença de mais defeitos do que o grupo One Shape, mas não houve diferença significante entre eles (P = .115). O grupo One Shape foi o único que apresentou FVR. Os resultados obtidos nesse estudo sugerem que o preparo biomecânico com instrumentos rotatórios e/ou de reciprocidade podem causar danos na dentina radicular.