Effect of violet LED light on in-office bleaching protocols: a randomized controlled clinical trial

Abstract Objective This study evaluated the clinical effect of violet LED light on in-office bleaching used alone or combined with 37% carbamide peroxide (CP) or 35% hydrogen peroxide (HP). Methodology A total of 100 patients were divided into five groups (n=20): LED, LED/CP, CP, LED/HP and HP. Colorimetric evaluation was performed using a spectrophotometer (ΔE, ΔL, Δa, Δb) and a visual shade guide (ΔSGU). Calcium (Ca)/phosphorous (P) ratio was quantified in the enamel microbiopsies. Measurements were performed at baseline (T 0 ), after bleaching (T B ) and in the 14-day follow-up (T 14 ). At each bleaching session, a visual scale determined the absolute risk (AR) and intensity of tooth sensitivity (TS). Data were evaluated by one-way (ΔE, Δa, ΔL, Δb), two-way repeated measures ANOVA (Ca/P ratio), and Tukey post-hoc tests. ΔSGU and TS were evaluated by Kruskal-Wallis and Mann-Whitney, and AR by Chi-Squared tests (a=5%). Results LED produced the lowest ΔE (p<0.05), but LED/HP promoted greater ΔE, ΔSGU and Δb (T 14 ) than HP (p<0.05). No differences were observed in ΔE and ΔSGU for LED/CP and HP groups (p>0.05). ΔL and Δa were not influenced by LED activation. After bleaching, LED/CP exhibited greater Δb than CP (p>0.05), but no differences were found between these groups at T 14 (p>0.05). LED treatment promoted the lowest risk of TS (16%), while HP promoted the highest (94.4%) (p<0.05). No statistical differences of risk of TS were found for CP (44%), LED/CP (61%) and LED/HP (88%) groups (p>0.05). No differences were found in enamel Ca/P ratio among treatments, regardless of evaluation times. Conclusions Violet LED alone produced the lowest bleaching effect, but enhanced HP bleaching results. Patients treated with LED/CP reached the same efficacy of HP, with reduced risk and intensity of tooth sensitivity and none of the bleaching protocols adversely affected enamel mineral content.

Effects of the combination of Er: YAG laser and sandblasting on the shear bond strength between zirconia and resin cement

Aim: This study was conducted to determine the bond strength between zirconia ceramic and resin luting cement according to the type of surface treatment applied. Methods: Sixty zirconia cylinders measuring 4 x 4 mm were manufactured and distributed into five experimental groups and a control group (n = 10): G1 - sandblasting with 110 µm aluminum oxide; G2 - sandblasting with 30 µm Rocatec Soft®; G3 - Er:YAG laser irradiation at 400 mJ; G4 - Er:YAG laser combined with sandblasting with aluminum oxide; G5 - Er:YAG laser combined with sandblasting with Rocatec Soft®; G6 - no treatment (Control). The zirconia cylinders were bonded in the center of composite resin cylinders (6 mm diameter) using RelyX Ultimate® cement. Shear strength was measured after thermocycling (6000 cycles and 5-55° C). Data were analyzed using one-way ANOVA and Tukey's post-hoc with a 5% significance level. Results: Group 4 had a significantly higher shear strength than all the other groups, except Group 1. Group 3 had a significantly lower shear strength compared with Groups 1 and 4. Conclusion: Sandblasting with 110µm aluminum oxide particles after laser irradiation may be an effective zirconia surface treatment. The use of Er: YAG laser alone is not effective at increasing the bond between resin cement and zirconia

Do metal alloy primers increase the bond strength of orthodontic tubes?

Aim: To evaluate the bond strength (BS) and failure mode of orthodontic tubes treated with different alloy primers at the interface among enamel, resin and orthodontic tubes. Methods: Orthodontic tubes were bonded to the enamel of 80 bovine incisors with the orthodontic resin (Transbond XT, 3M Unitek). Prior to bonding, the tubes were chemically treated with (n=20) Metal/Zirconia Primer (MZ, Ivoclar), Scothbond Universal (SB, 3M Espe); Orthoprimer (OP, Morelli) or left untreated (Control - C). Specimens were submitted to 5,000 thermal cycles (5 and 55o C) to age the bonded interface. A shear BS test and failure modes were conducted, and the results were analyzed using one-way analysis of variance and Fisher's exact test, respectively. Results: No differences were observed among groups regardless of the type of alloy primer used (p = 0.254). However, no differences were observed among the failure modes of the groups tested (p=0.694). The adhesive failure mode between the resin and enamel was the most prevalent failure (45%) for groups OP and C, whereas cohesive failure in the orthodontic resin was the most prevalent failure (40%) for groups SB and MZ. Conclusion: Alloy primers were unable to increase the BS of the orthodontic tubes to enamel

Influence of the ultrasonic activation of irrigating solutions on sealer penetration into lateral root canals / influência da ativação ultrassônica de soluções irrigadoras na penetração de cimento obturador em canais laterais

ABSTRACT Objective: This study analyzed the influence of the irrigating solutions ultrasonic activation on the obturator cement penetration into lateral root canals. Methods: Fifty maxillary molars (palatine root) were randomly assigned to 5 experimental groups (Group 1 (EDTA 17% + manual agitation for 5 minutes), Group 2 (EDTA 17% + ultrasonic activation for 15 seconds), Group 3 (NaOCl 1% + Ultrasonic activation for 15 seconds), Group 4 (EDTA 17% + ultrasonic activation for 15 seconds and NaOCl 1% + ultrasonic activation for 15 seconds) and Group 5 (negative control). The lateral root canals were made in the apical and middle third. The obturation occurred in a single session. The radiographic and microscopic analyzes were performed to evaluate the sealant cement penetration degree. Data were analyzed by the Mann-Whitney and Wilcoxon tests. Results: Apical and middle third radiographic analysis showed that Groups 2 and 4 presented better penetration of the sealant cement. In the microscopic analysis, Group 4 presented superior results in relation to the other groups in both thirds. In the apical third, radiographic and microscopic analyzes showed significant differences in the comparisons between Group 4 and Groups 5 (p = 0.019) and 3 (p = 0.023) and between Group 5 and Groups 2 (p = 0.012), 3 (P = 0.038) and 4 (p = 0.019), respectively. Conclusion: It was concluded that the ultrasonic activation of the NaOCl 1% + EDTA 17% irrigation solution provides greater penetration of the endodontic cement in lateral root canals.

RESUMO Objetivo: Este trabalho analisou a influência da ativação ultrassônica de soluções irrigadoras na penetração do cimento obturador em canais laterais. Métodos: Cinquenta molares superiores (raiz palatina) foram distribuídos aleatoriamente em 5 grupos experimentais (n=10): Grupo 1 (EDTA 17% + agitação manual por 5 minutos), Grupo 2 (EDTA 17% + ativação ultrassônica por 15 segundos), Grupo 3 (NaOCl 1% + ativação ultrassônica por 15 segundos), Grupo 4 (EDTA 17% + ativação ultrassônica por 15 segundos e NaOCl 1% + ativação ultrassônica por 15 segundos) e Grupo 5 (controle negativo). Os canais laterais foram confeccionados nos terços médio e apical. A obturação ocorreu em sessão única e foram realizadas análises radiográficas e microscópicas para avaliar o grau de penetração do cimento obturador. Os dados foram analisados pelos testes de Mann-Whitney e Wilcoxon. Resultados: A análise radiográfica do terço apical e médio mostrou que os Grupos 2 e 4 apresentaram melhor penetração do cimento obturador. Já na análise microscópica, o Grupo 4 apresentou resultados superiores em relação aos demais grupos em ambos os terços. No terço apical, as análises radiográfica e microscópica exibiram diferenças significativas nas comparações entre o Grupo 4 com os Grupos 5 (p = 0,019) e 3 (p = 0,023) e entre o Grupo 5 com os Grupos 2 (p = 0,012), 3 (p = 0,038) e 4 (p = 0,019), respectivamente. Conclusão: Conclui-se que a ativação ultrassônica da solução irrigadora NaOCl 1% + EDTA 17% proporciona maior penetração do cimento endodôntico em canais laterais.

Influence of a new method of sterilization on the morphology and physical properties of extracted human teeth / Influência de um novo método de esterilização na morfologia e propriedades físicas de dentes humanos extraídos

Introduction: Sterilization methods adopted in Human Teeth Bank can promote structural changes in enamel and dentin. Thus, the ideal method should combine the antimicrobial efficacy and preservation of the substrate biomechanical properties. Aim: Evaluated the morphology and physical properties of enamel and dentin of extracted human teeth, after being submitted to different sterilization methods. Method: Sixteen extracted third molars were sectioned in the following tooth regions: mesio-distal, vestibular-lingual and at the cement enamel junction. Forty specimens were selected according to values of microhardness and roughness initials, and distributed in four experimental groups (n = 10/group): Group 1 = Autoclave 121 °C (30 minutes); Group 2 = 2.5% Sodium hypochlorite (07 days); Group 3 = 5.25% Sodium hypochlorite (07 days); Group 4= 30% Acetic Acid (7 days). After sterilization, the microhardness, roughness and morphology of enamel and dentin were evaluated. Data were analyzed by paired t-test, Wilcoxon, Kruskal-Wallis and Analysis of Variance. A significance level of 5% was adopted. Result: All sterilization methods altered the microhardness and roughness of the dentine (p <0.05). Regarding to enamel, the microhardness was affected only by Autoclave and 2.5% Sodium hypochlorite treatment (p <0.05). A large aperture of the enamel pores and dentinal tubules was verified in the micrographs. Conclusion: The sterilization methods adopted altered the morphology and/or physical properties of enamel and dentine.

Introdução: Métodos de esterilização adotados em Banco de Dentes Humanos podem promover mudanças estruturais no esmalte e na dentina. Assim, o método ideal deve combinar a eficácia antimicrobiana e a preservação das propriedades biomecânicas do substrato. Objetivo: Avaliar a morfologia e propriedades físicas do esmalte e dentina dos dentes humanos extraídos, após serem submetidos a diferentes métodos de esterilização. Método: Dezesseis terceiros molares extraídos foram seccionados nas seguintes regiões dentárias: mesio-distal, vestibulo-lingual e na junção amelocementária. Quarenta espécimes foram selecionados de acordo com valores de microdureza e rugosidade iniciais, e distribuídos em quatro grupos experimentais (n = 10 / grupo): Grupo 1 = Autoclave 121 °C (30 minutos); Grupo 2 = 2,5% de hipoclorito de sódio (07 dias); Grupo 3 = 5,25% Hipoclorito de sódio (07 dias); Grupo 4 = ácido acético a 30% (7 dias). Após a esterilização, foi avaliada a microdureza, rugosidade e morfologia do esmalte e dentina. Os dados foram analisados ​​pelo teste t pareado, Wilcoxon, Kruskal-Wallis e Análise de Variância. Um nível de significância de 5% foi adotado. Resultado: Todos os métodos de esterilização alteraram a microdureza e a rugosidade da dentina (p <0,05). Em relação ao esmalte, a microdureza foi afetada apenas pela Autoclave e pelo tratamento com 2,5% de hipoclorito de sódio (p <0,05). Foi verificada nas micrografias, uma grande abertura dos poros do esmalte e dos túbulos dentinários. Conclusão: os métodos de esterilização adotados alteraram a morfologia e / ou propriedades físicas do esmalte e da dentina.

Effects of experimental bleaching agents on the mineral content of sound and demineralized enamels

Abstract High concentrations of hydrogen peroxide can cause adverse effects on composition and structure of teeth. However, the addition of calcium and fluoride in bleaching agents may reduce enamel demineralization. Objective: To evaluate chemical changes of sound and demineralized enamels submitted to high concentrations of hydrogen peroxide containing fluoride (F) or calcium (Ca). Material and Methods: Enamel blocks of bovine incisors with standard dimensions were obtained and half of them were submitted to pH-cycling to promote initial enamel caries lesions. Sound and demineralized enamel samples were divided into (n=10): (C) Control (no whitening treatment); (HP) 35% hydrogen peroxide; and two experimental groups: (HPF) 35% HP+0.2% F and (HPC) 35% HP+0.2% Ca. Experimental groups were submitted to two in-office bleaching sessions and agents were applied 3 times for 15 min to each session. The control group was kept in remineralizing solution at 37°C during the bleaching treatment. The surface mineral content of sound and demineralized enamels was determined through Fourier Transform Raman spectroscopy (FT-Raman), Energy dispersive Micro X-ray fluorescence spectroscopy (μ-EDXRF); and the subsurface, through cross-sectional microhardness (CSMH). In addition, polarized light microscopy (PLM) images of enamel subsurface were observed. Results: According to three-way (FT-Raman and μ-EDXRF analyses) or two-way analysis of variance (ANOVA) (CSMH) and Tukey test (α=5%), the calcium or fluoride added to high-concentrated bleaching agents increased phosphate and carbonate concentrations on sound and demineralized enamels (p<0.05). However, HPC and HPF were unable to completely reverse the subsurface mineral loss promoted by bleaching on sound and demineralized enamels. The calcium/ phosphate (Ca/P) ratio of sound enamel decreased after HP treatment (p<0.001). Conclusion: Even though experimental bleaching agents with Ca or F reduced mineral loss for both sound and demineralized enamel surfaces, these agents were unable to reverse the enamel subsurface demineralization.

Tratamento endodôntico e cirúrgico em dens invaginatus tipo III: 3 anos de acompanhamento utilizando TCFC / Endodontic and surgical treatment in type III dens invaginatus: a 3-year follow-up with CBCT

Introdução: o defeito da morfologia nos dens invaginatus provoca falta de suprimento sanguíneo para a polpa e consequente necrose pulpar, culminando em lesão periapical. A intervenção com cirurgia paraendodôntica é comum nesses casos, em que o tratamento endodôntico conservador não é bem-sucedido, devido à complexa anatomia e inacessibilidade do tecido pulpar. Esse caso relata um tratamento endodôntico cirúrgico bem-sucedido, como evidenciado pela Tomogra a Computadorizada de Feixe Cônico (TCFC), em dens in dente tipo III com lesão periapical considerável. O tratamento endodôntico foi realizado em sessão única, seguido por apicectomia e retropreparo da cavidade, com auxílio de microscópio operatório e uso de pontas ultrassônicas, e obturação retrógrada com Agregado Trióxido Mineral (MTA). Osso bovino lio lizado e membrana de colágeno foram inseridos para preencher a cavidade. Após três anos de acompanhamento, radiogra as periapicais, TCFC e reconstrução 3D foram realizadas, apresentando resultados favoráveis no que diz respeito ao reparo da lesão.

Retratamento endodôntico em dens in dente com insertos ultrassônicos e iodofórmio: 2 anos de follow-up / Endodontic retreatment in dens in dente using ultrasonic tips and iodoform: a 2-year follow-up

Dens in dente (dens invaginatus) é uma anomalia de desenvolvimento que afeta a formados dentes. O órgão do esmalte é desorganizado e ocorre a invaginação da coroa do dente antes da fase de calcificação. O relato deste caso tem como objetivo apresentar o uso de inserto sultrassônicos e medicação intracanal com iodofórmio no retratamento endodôntico em dens indente tipo II com lesão periapical. O dente necessitou de retratamento endodôntico. O acesso coronário e a instrumentação dos canais radiculares foram realizados com auxílio de insetos ultrassônicos. Utilizou-se iodofórmio e hidróxido de cálcio como medicação intracanal em duas sessões. Na última sessão, a obturação foi realizada. Após dois anos de follow-up, observou-se sucesso no retratamento. O dente apresenta-se sem sintomatologia dolorosa e com redução da lesão periapical.

Dens in dente (dens invaginatus) is a developmental anomaly that affects the shape ofteeth. The enamel organ is disorganized and invagination of the tooth crown occurs before thecalcification stage. The aim of this case report is present the use of ultrasonic tips and intracanalmedication with iodoform in endodontic retreatment in dens in dente type II with periapicallesion. The tooth required endodontic retreatment. Coronal access and root canal instrumentationwere performed with the aid of ultrasonic tips. Iodoform and calcium hydroxide were usedas intracanal medication in two sessions. In the last session, filling was performed. After follow--up of 2 years, successful retreatment was observed. The tooth presented no painful symptomsand the periapical lesion was reduced.