Bond strength of bulk fill composite to teeth prepared with Er: YAG laser

Aim: The present in vitro study aimed to evaluate the bond strength of a bulk fill composite on dentin surfaces prepared with the Er: YAG laser. Methods: Twenty-four permanent third molars were selected and divided into 2 groups: CP - Conventional preparation with high-speed handpiece (control) and LA (laser) - Preparation with Er: YAG laser. The occlusal surface was removed to expose coronal dentin, which was subsequently prepared with a high-speed handpiece or Er: YAG laser (350mJ, 4Hz, 1.5 ml/min water flow). Both groups were restored with Filtek One Bulk Fill (3M ESPE) composite resin. After 24 hours, the samples were evaluated for microtensile bond strength (µTBS), fracture pattern, and scanning electron microscopy (SEM). Results: The data obtained in the µTBS test were submitted to t-test (α=0.05). The results showed no difference in µTBS when the different types of cavity preparation were compared (ρ=0.091). Fracture patterns revealed the prevalence of cohesive fracture in composite resin in CP (83.3%) and adhesive fracture in LA (92.1%). In the SEM analysis, the LA group demonstrated the presence of gaps between the composite resin and the irradiated dentin surface. The hybrid layer exhibited more regularity with the presence of longer and uniform resin tags in the CP group. Conclusion: The type of cavity preparation did not influence the values of bulk fill composite resin µTBS to dentin. Fracture patterns and scanning electron microscopy analyses suggested less interference at the adhesive interface in preparations performed using CP

Substituição de restauração classe IV em resina composta: relato de caso clínico / Class IV restoration replacement in composite resin: clinical case report

Introdução: a estética é um fator decisivo para a substituição de restaurações anteriores que apresentam falhas, causadas principalmente por alterações na coloração ou fraturas. Objetivo: o presente relato de caso descreve a substituição de uma restauração classe IV insatisfatória, apresentando o protocolo clínico utilizado desde o planejamento até a reabilitação definitiva, com o propósito de difundir o conhecimento sobre a técnica adotada e auxiliar outros profissionais no seu cotidiano clínico. Relato do caso: paciente JPJ, 28 anos, sexo masculino, apresentou-se ao consultório odontológico queixando-se do aspecto estético de uma restauração em resina composta no seu dente anterior. Durante o exame físico intrabucal foi identificada a presença de uma restauração classe IV insatisfatória no elemento 21, apresentando degradação e manchamento superficial. Para uma análise estética completa e planejamento do caso, foram realizadas fotografias intrabucais e moldagem com alginato para confecção de modelos de gesso. Resultados: como tratamento, foi realizado profilaxia, isolamento absoluto e substituição da restauração do dente 21 pela técnica direta com o auxílio de uma guia de silicone. Foi utilizado um sistema adesivo convencional de 2 passos (Single Bond 2, 3M ESPE, St. Paul, MN, USA) e resinas compostas nanohíbridas (Empress Direct, Ivoclar-Vivadent, Barueri, SP, BRA), uma para reprodução do esmalte e outra para dentina. Por fim, foram realizados acabamento e polimento das restaurações. Conclusão: restaurações diretas com resinas compostas, quando bem indicadas e executadas, permitem a devolução da função de forma satisfatória e resultados altamente estéticos.

Introduction: aesthetics are a decisive factor in replacing anterior restorations that present failures, mainly caused by color changes or fractures. Objective: this case report describes the replacement of a class IV restoration with composite resin by the direct technique, presenting the clinical protocol used, from planning to definitive rehabilitation, with the purpose of spreading knowledge of the technique and helping other professionals in their daily clinical routine. Case report: patient JPJ, 28 years old, male, presented to the dental office complaining about the aesthetic aspect of a composite resin restoration on his anterior tooth. During the intraoral physical examination, the presence of a class IV restoration in element 21 was identified, which was unsatisfactory due to degradation and surface staining. For a complete and detailed esthetic analysis, intraoral photographs and molding with alginate were taken to make plaster models. Results: as a treatment, prophylaxis, absolute isolation and replacement of the restoration of tooth 21 were performed by the direct technique with the aid of a silicone guide. A conventional 2-step adhesive system (Single Bond 2, 3M ESPE, St. Paul, MN, USA) and nanohybrid composite resins (Empress Direct, Ivoclar-Vivadent, Barueri, SP, BRA) were used, one for enamel reproduction and another for dentine. Finally, finishing and polishing of the restorations were carried out. Conclusion: direct restorations with composite resins, when properly indicated and executed, allow the return of function in a satisfactory way and highly esthetic results.

Effect of violet led associated with low-concentration hydrogen peroxide on enamel surface roughness

Aim: The present study aimed to assess in vitro the effect ofviolet LED in tooth bleaching techniques associated or not withlow-concentration hydrogen peroxide gel on enamel surfaceroughness. Methods: Fifty-two enamel fragments of bovineteeth were flattened and polished (4x4x3 mm) and dividedinto four groups according to bleaching treatment: VL- VioletLED; HP- 7.5% hydrogen peroxide; HP+VL- 7.5% hydrogenperoxide + violet LED; C- No bleaching (control). Before thetreatments, all specimens were immersed in 20 mL of blacktea for six days, changing solutions every 24 h to simulatethe staining of specimens. Forty fragments were used toanalyze surface roughness (n=10) and 12 fragments wereused for the morphological analysis (SEM) (n=3). Results:The data were submitted to one-way ANOVA and a post-hocTukey test. The lower roughness values was observed for thegroup that did not receive bleaching treatment (C), differingsignificantly only from the group bleached with 7.5% hydrogenperoxide + violet LED (HP+VL) (p=0.0077). The remaininggroups did not show significant differences in roughnessvalues (p>0.05). The scanning electron microscopy analysisshowed irregularities on the enamel surface regardless ofthe treatment received. Conclusion: The results showedthat bleaching treatments with violet LED associated withlow-concentration hydrogen peroxide gels (7.5%) increasethe surface roughness of tooth enamel

Effect of grape seed extract on bond strength of restorative material to bleached enamel

Objective: The aim of this study was to evaluate the effect of different concentrations of a natural antioxidant (grape seed extract) on the bond strength of the restorative material to the bleached enamel. Methods: Forty fragments of healthy bovine incisors were randomly divided into four groups (n = 10): Group I: no bleaching; Group II: Bleaching with 35% hydrogen peroxide (HP) and without post-treatment; Group III: Bleaching with 35% HP + 5% grape seed extract; and Group IV: Bleaching with 35% HP + 10% grape seed extract. The bond strength at the adhesive interface was evaluated using the shear test (MPa). The data were analyzed by the analysis of variance (ANOVA) and Tukey test ( =0.05%). The fracture types were also analyzed and classified into: adhesive, cohesive or mixed. Results: Only Group III (bleached + 5% grape seed extract) had a significant increase (p<0.001) in bond strength values when compared to Group II bleached, without post- reatment). All groups showed a predominance of the adhesive type of fracture. Conclusion: It could be concluded that tooth bleaching decreases the bond strength to bleached enamel and 5% grape seed extract applied after dental bleaching improves the bond strength between the restorative material and the bleached enamel.

Objetivo: Este trabalho teve por objetivo avaliar in vitro o efeito de um antioxidante natural (extrato de semente de uva) em diferentes concentrações, na resistência de união do material restaurador ao esmalte clareado. Métodos: Quarenta fragmentos de incisivos bovinos hígidos, foram divididos aleatoriamente em quatro grupos (n=10): Grupo I: sem clareamento; Grupo II: clareado com peróxido de hidrogênio 35% (PH) e sem pós-tratamento; GIII: clareado PH 35% + extrato de semente de uva 5%; e Grupo IV: clareado com PH 35% + extrato de semente de uva 10%. A resistência de união da interface esmalte/material restaurador foi avaliada por meio do teste de cisalhamento (MPa). Os dados foram analisados pela análise de variância (ANOVA) e testes de Tukey ( =0,05%). Os tipos de fratura também foram analisados e classificados em: adesiva, coesiva ou mista. Resultados: Apenas o Grupo III (clareado + extrato de semente de uva 5%) apresentou aumento estatisticamente significante (p<0,001). dos valores de resistência de união comparado ao Grupo II (clareado e sem pós-tratamento). Todos os grupos mostraram um predomínio do tipo de fratura adesiva. Conclusão: O clareamento dental diminui significativamente a força de adesão ao esmalte dental clareado, e o extrato de semente de uva 5% aplicado após o clareamento dental melhora a resistência de união entre o material restaurador e o esmalte clareado.

Non-contact profilometry of eroded and abraded enamel irradiated with an Er: YAG laser

Abstract Literature has reported positive results regarding the use of lasers in the control of erosive lesions; however, evaluating whether they are effective in the control of the progression of erosive/abrasive lesions is important. Objectives This study aimed to evaluate the effect of the Er:YAG laser irradiation in controlling the progression of erosion associated with abrasive lesions in enamel. Material and methods Bovine incisors were sectioned, flattened and polished. Forty-eight enamel slabs were subjected to treatment in an intraoral phase. Twelve volunteers used an intraoral appliance containing one slab that was irradiated with an Er:YAG laser (5.2 J/cm2, 85 mJ, 2 Hz) and another non-irradiated slab on each side of the appliance, during one phase of 5 d, under a split-mouth design. Devices were subjected to erosive challenges (1% citric acid, 5 min, 3 times a day) and abrasive challenges one h after (brushing force of 1.5 N for 15 s) randomly and independently on each side of the device. Measurements of enamel loss were performed via 3D optical profilometry (μm). We analyzed data using the Kruskal-Wallis and Mann-Whitney tests and morphological characteristics via scanning electron microscopy. Results Following erosive and abrasive challenges, the group that was irradiated with the Er:YAG laser presented less loss of structure than the non-irradiated group. The group that underwent erosion and irradiation did not exhibit a significant difference from the non-irradiated group. Conclusion Irradiation with the Er:YAG laser did not control the loss of structure of enamel subjected to erosion but did control abrasion after erosion.

Effect of Fluoride Varnish Combined with Er:YAG Laser on the Permeability of Eroded Dentin: An In Situ Study

This study evaluated the combined effect of fluoride varnish and Er:YAG laser on the permeability of eroded bovine root dentin. After initial erosive challenge followed by a remineralization period, the specimens were divided in two groups according to the treatment - fluoride varnish and non-fluoride varnish - and were subdivided according to the irradiation protocol: Er:YAG laser (100 mJ, 3 Hz, 12.8 J/cm2per pulse, non-contact and defocus mode) and non-irradiated. After a lead-in period, 7 volunteers wore a palatal device containing 4 specimens that were subjected to erosive challenges. At the first experimental phase, 4 volunteers used specimens treated with fluoride varnish and fluoride varnish+Er:YAG laser and 3 volunteers used specimens treated with non-fluoride varnish and non-fluoride varnish+Er:YAG laser. After a washout period, volunteers were crossed to treatments, characterizing a 2x2 crossover experiment. At the end of the experimental phase, the quantitative response variable was obtained by permeability analysis and the qualitative response by scanning electron microscopy (SEM). Two-way ANOVA and Tukey-Kramer's test revealed that specimens treated with fluoride varnish+Er:YAG laser showed the lowest permeability and a significant difference was found between this group and the others. When varnish (fluoride/non-fluoride) was applied in the absence of Er:YAG laser, higher permeability was found when compared to the laser-treated groups. SEM evaluations showed partially or completely obliterated dentinal tubules when specimens were treated with fluoride varnish+Er:YAG laser. It may be concluded that Er:YAG laser was able to control the permeability of eroded root dentin and the combination with fluoride varnish increased laser action.

Resumo Esse estudo avaliou o feito combinado do verniz fluoretado ao laser de Er:YAG na permeabilidade da dentina radicular erodida. Fragmentos de dentina radicular bovina, foram submetidos a um desafio erosivo inicial com ácido cítrico, que foi seguido por um período de remineralização. Posteriormente, os espécimes foram divididos em relação aos tratamentos: verniz (fluoretado e não fluoretado) e subdivididos de acordo com a irradiação: laser de Er:YAG (100 mJ, 3 Hz, 12.8 J/cm2 por pulso, sem contato e modo não focado) e não irradiado. Após um período de lead in, 7 voluntários utilizaram um dispositivo palatino contendo 4 espécimes que foram submetidos a desafios erosivos. Na primeira fase do experimento, 4 voluntários utilizaram dispositivos com fragmentos tratados com verniz fluoretado e verniz fluoretado+laser de Er:YAG e 3 voluntários utilizaram espécimes tratados com verniz não fluoretado e verniz não fluoretado+laser de Er:YAG. Depois de um período de wash-out, os voluntários foram cruzados em relação aos tratamentos, caracterizando um experimento cross-over 2x2. Ao final de cada fase experimental, a variável resposta quantitativa foi obtida através da análise de permeabilidade e a qualitativa por microscopia eletrônica de varredura (MEV). A ANOVA dois critérios e teste de Tukey-Kramer revelou que as amostras tratadas com verniz fluoretado+laser de Er:YAG mostraram menor permeabilidade e uma diferença significativa foi encontrada entre este grupo, quando comparado aos demais grupos. Quando o verniz (fluoretado/não fluoretado) foram aplicados na ausência do laser de Er:YAG maiores valores de permeabilidade foram encontrados quando comparados com os grupos irradiados com o laser. A MEV demostrou túbulos dentinários parcialmente ou completamente ocluídos quando as amostras foram tratadas com verniz fluoretado+laser de Er: YAG. Pode-se concluir que o laser de Er:YAG foi capaz de controlar a permeabilidade da dentina radicular erodida e essa ação é aumentada quando o laser está associado ao verniz fluoretado.

Laser de CO2 no controle da desmineralização do esmalte: uma análise crítica / CO2 laser in the control of enamel demineralization: a critical analysis

Frente à dificuldade de controlar processos de desmineralização do esmalte, novas tecnologias vêm sendo estudadas como o emprego da irradiação com laser de CO2. Assim, o objetivo deste trabalho foi apresentar uma revisão de literatura crítica do laser de CO2 no controle da desmineralização do esmalte, abordando seu mecanismo de ação em esmalte, parâmetros de utilização para a estrutura dental e sua associação a agentes fluoretados. O laser de CO2 parece ser um método promissor no controle da desmineralização do esmalte, porém, mais estudos são necessários para empregabilidade clínica. O efeito sinérgico com flúor, mesmo com diferentes agentes fluoretados, revelou resultados positivos no controle da desmineralização do esmalte.