This study quantified alterations in root dentin permeability after exposure to different acid beverages. Twenty-five third molars were sectioned below the cementoenamel junction, the root segment was collected, and the pulp tissue was removed. The root segments were connected to a hydraulic pressure apparatus to measure the permeability of root dentin after the following sequential steps, with 5 specimens in each: 1) phosphoric acid etching for 30 s (maximum permeability), 2) root planning to create new smear layer, 3) exposure to different acid substances for 5 min (orange, cola drink, vinegar, white wine, lemon juice), 4) toothbrushing with sonic toothbrush for 3 min, 5) toothbrushing with sonic toothbrush plus dentifrice for 3 min. Considering step I as 100%, the data were converted into percentage and each specimen was its own control. Data were analyzed statistically by Kruskal-Wallis and Dunn's post test at 5% significance level. All acidic substances increased dentin permeability significantly after scraping (p<0.05). Toothbrushing after exposure to acid substances decreased dentin permeability and the association with dentifrice accentuated the decrease (p<0.05), except for the specimens treated with cola drink. Thus, it may be concluded that all tested acid fruit juices increased dentin permeability, and toothbrushing with or without dentifrice can decrease root dentin permeability after dentin exposure to acid diet.

BackgroundConsidering the current high use of high fluoride toothpastes, the aim of the study was to quantify alterations in the root dentine permeability submitted to treatment with a high fluoride toothpaste and 8% arginine, calcium carbonate, sodium monofluorophosphate toothpaste as a preventive treatment for dentinal tubules exposure followed by acid challenge.MethodsThirty-third molars were sectioned below the cementoenamel. The root segments were connected to a hydraulic pressure apparatus to measure dentine permeability after the following sequential steps (n = 10 per group): I) Baseline; II) treatment with phosphoric acid for 30 s (maximum permeability); III) Toothbrushing (1 min) according to the experimental groups (G1- control; G2- 5000 ppm fluoride toothpaste; G3- 8% arginine-calcium carbonate toothpaste); IV) acid challenge for 5 min (orange juice). The data were converted into percentage, considering stage II as 100%.ResultsThe results have shown a statistically significant decreasing on dentine permeability after treatment with toothpaste (Friedman test and Dunn’s post hoc test). Comparison among groups demonstrated a high increasing on dentine permeability when acid challenge was performed after toothbrushing with distilled water (control group) (Kruskal-Wallis and Dunn’s post hoc test).ConclusionThe toothpaste treatment may provide sufficient resistance on dentine surface, preventing dentinal tubules exposure after acid challenge.

INTRODUCTION: Biomaterials such as bioactive glasses and glass-ceramics have been proposed for the treatment of dentinal hypersensitivity. OBJECTIVE: to evaluate by scanning electron microscopy (SEM), the dissolution of a novel bioactive glass-ceramic (Biosilicate® 1-20 µm particles) on dentin surface samples, with different application methods and different dilution medium used for applying Biosilicate®. MATERIAL AND METHOD: 280 dentin samples were randomly divided into four groups: (1) Biosilicate® plus fluoride gel applied with Robinson brush; (2) Biosilicate® plus fluoride gel applied with microbrush; (3) Biosilicate® plus distilled water applied with Robinson brush; (4) Biosilicate® plus distilled water applied with microbrush. After treatment, the samples were immersed in saliva at different periods (0, 15 and 30 minutes, 1, 2, 12 and 24 hours). Two photomicrographs were obtained from each sample and were further analyzed by a blind calibrated examiner according to a "Particle Dissolution Index" created for this study. RESULT: The data were analyzed using the Mann-Whitney, Kruskal-Wallis and Dunn's tests. There was no statistical difference among the degrees of dissolution between the 4 groups in any period. CONCLUSION: Biosilicate® can be incorporated in both substances without differences in the degree of dissolution of the particles in any of the evaluated periods and the application of dentine can be performed with both methods evaluated.

The purpose of this in vitro study was to quantify the alterations on human root dentin permeability after exposure to different acid fruit juices and to evaluate the effect of toothbrushing with electric or sonic toothbrush after acid exposure. The root dentin of 50 extracted third molars was exposed with a high speed bur. Crowns were sectioned above the cementoenamel junction and root fragments were used to prepare dentin specimens. Specimens were randomly assigned to 5 groups according to the fruit juice (kiwifruit, starfruit, green apple, pineapple and acerolla). Each specimen was connected to a hydraulic pressure apparatus to measure root dentin permeability using fluid filtration method after the following sequential steps: I) conditioning with 37% phosphoric acid for 30 s, II) root scaling, III) exposure to acid fruit juices for 5 min and IV) electric or sonic toothbrushing without dentifrice for 3 min. Data were analyzed statistically by the Wilcoxon and Mann-Whitney tests at 5% significance level. All fruit juices promoted a significant increase of dentin permeability while toothbrushing decreased it significantly (p<0.05). It may be concluded that all acid fruit juices increased root dentin permeability, while toothbrushing without dentifrice after acid exposure decreased the permeability. The toothbrush mechanism (electric or sonic) had no influence on the decrease of root dentin permeability.

AimTo assess the influence of artefacts generated by metal posts on the detection of simulated internal root resorption (IRR) in adjacent teeth using cone‐beam computed tomography (CBCT) and to verify the impact of metal artefact reduction (MAR) on these cases.MethodologyCBCT images of 14 premolar teeth were acquired before and after IRR simulation using chemical and mechanical procedures, in an OP300 Maxio unit, with and without MAR. Each tooth was placed in the socket of a human mandible and scanned under three different conditions: (i) without adjacent teeth – control group; (ii) distal adjacent tooth restored with metal post; and (iii) with both adjacent teeth restored with metal post. Five oral radiologists scored the IRR detection using a 5‐point scale. Diagnostic values were obtained for the tested groups and compared using two‐way analysis of variance (α = 0.05).ResultsThe presence of a single adjacent tooth restored with metal post did not significantly influence the diagnostic values for IRR detection (P > 0.05). The presence of both adjacent teeth with metal posts, without MAR application, was associated with a significantly lower area under the ROC curve (Az) compared to the control (P = 0.0182). In this case, the application of MAR increased Az, leading to nonsignificant differences from the control group and the group with one adjacent restored tooth (P > 0.05). Sensitivity decreased significantly when two adjacent restored teeth were present, regardless of MAR application (P = 0.0379). Specificity was not affected by the conditions tested (P > 0.05).ConclusionCBCT detection of IRR was impaired by artefacts only when both adjacent teeth restored with metal posts were present. In such cases, activation of MAR improved the performance on this diagnostic task.

AGRADECIMENTOSAo Prof. Dr. José Eduardo Cezar Sampaio, por ter acreditado em mim e com muita paciência ter me orientado durante esses dois anos. Obrigada pelo carinho e apoio! As minhas queridas amigas Andressa, Telma, Chaine, Shelon e Samia por terem me acompanhado durante esses dois anos com tanto carinho.Vocês tornaram tudo muito mais fácil e divertido. Amigas que vou levar pra sempre dentro do meu coração. Amo vocês.Aos amigos Guilherme e Lucas por terem me ajudado tanto no inicio quando não pude freqüentar as aulas, serei sempre grata a vocês.A todos os alunos de mestrado e doutorado pela companhia e a todos os professores da disciplina de Periodontia pelos ensinamentos.A queridíssima Zezé que ilumina nossos dias com sua alegria.A Dona Maria, que colaborou tanto com este trabalho.A Regina Lúcia sempre muito prestativa.Ao amigo Rodrigo Cavassim pela colaboração não só com este trabalho mas durante todo o mestrado.A Beatriz Valério pela colaboração e ajuda nessa etapa final do trabalho.. 9A minha sogra Margareth Bressa por me ajudar tanto nesses últimos anos, me dando apoio e me ajudando muito com a minha filhinha, mas principalmente por sempre acreditar que sempre dá pra fazer tudo.Aos meus cunhados André, Talita, Mariana, e Mauricio pelo carinho e pelos cuidados comigo e com minha filha.A minha irmãzinha Ana Carolina Toledo, por fazer parte da minha vida de forma tão carinhosa. Eu te amo irmãzinha.Enfim, a todos que contribuíram não só para a execução deste trabalho mas também durante toda a minha caminhada. RESUMOO tratamento da hipersensibilidade dentinária cervical ainda é tema de diversos estudos em odontologia, pois um resultado permanente e satisfatório para essa sintomatologia dolorosa ainda não foi encontrado. Uma possibilidade nova de tratamento pode ser a utilização de vidros bioativos, que podem formar hidroxicarbonatoapatita sobre a superfície dentinária e obliterar os túbulos dentinários, no entanto, as formulações disponíveis deste material apresentam inconvenientes que dificultam sua aplicação sobre a superfície dentinária.Este estudo buscou avaliar a dissolução das partículas de uma vitrocerâmica modificado, denominado Biosilicato®, sobre a superfície dentinária, em diferentes veículos de preparo e formas de aplicação. Foram obtidos espécimes de dentina para a aplicação do produto testado e divididos em grupos que variavam quanto à forma de aplicação do Biosilicato® (escova de Robinson ou microbrush) e veiculo utilizado para a aplicação do produto (água ou flúor). Após a aplicação do produto sobre os espécimes estes foram imersos em saliva artificial e deixados em repouso em diferentes tempos: 0 minuto; 15 minutos; 30 17 minutos; 1 hora; 2 horas; 12 horas e 24 horas e depois levados para secar antes de serem analisadas no microscópio eletrônico de varredura. Após a obtenção das fotomicrografias, estas foram examinadas por um examinador calibrado e cego que atribuiu a elas um escore que variou de 1 a 3, segundo um "Índice de Dissolução de Partículas". A análise estatística não mostrou difer...