Association of defects of enamel with polymorphisms in the vitamin D receptor and parathyroid hormone genes.

This cross-sectional study aimed to investigate the association between developmental defects of enamel (DDE) and single nucleotide polymorphisms (SNPs) in the genes encoding the vitamin D receptor (VDR) and parathyroid hormone (PTH). Orthodontic patients receiving treatment at a dental school were selected through convenience sampling. Intra-oral photographs were used to assess DDE, which were classified according to the criteria proposed by Ghanim et al. (2015) by a single calibrated examiner (Kappa>0.80). Enamel hypoplasia, molar-incisor hypomineralization (MIH), hypomimineralized second primary molar (HSPM), and non-MIH/HSPM demarcated opacities were considered for the analysis. Genomic DNA was extracted from buccal cells. The SNPs in VDR (rs7975232) and PHT (rs694, rs6256, and rs307247) were genotyped using real-time polymerase chain reactions (PCR). Statistical analyses were performed using the PLINK software (version 1.03, designed by Shaun Purcell, EUA). Chi-square or Fisher's exact tests were performed at a significance level of 5%. Ninety-one (n=91) patients (49 females and 42 males) (mean age of 14.1±5.8 years) were included. The frequency of DDE was 38.5% (35 patients). Genotype distributions were in Hardy-Weinberg equilibrium. No significant statistical association was found between DDE and the SNPs evaluated. A borderline association (p=0.09) was observed between DDE and the CC haplotype for SNP rs7975232 in VDR. In conclusion, the selected SNPs in VDR and PTH genes were not associated with DDE in the studied samples.

Influence of Er:YAG and ND:YAG laser irradiation and fluoride application on surface roughness and dentin surface wear after erosive challenge - An in vitro study.

Background: To evaluate the effectiveness of Er:YAG and Nd:YAG laser on dentin hypersensitivity prevention, associated or not to acidulated phosphate fluoride (APF) after erosive challenge. Material and Methods: 104 specimens were obtained from bovine dentine and divided into groups (n=13): G1: Er:YAG; G2: Er:YAG followed by application of APF; G3: application of APF followed by Er:YAG, simultaneously; G4: Nd:YAG; G5: Nd:YAG followed by application of APF; G6: application of APF followed by Nd:YAG, simultaneously; G7:application of APF; G8: untreated. The parameters for Er:YAG were:10s, distance of 4mm, water cooling flow of 2mL/min, 2Hz, 3.92J/cm2. For the Nd:YAG: 10s, distance of 1mm, without cooling, 10Hz, 70.7J/cm2. The erosive drink was a cola at 4°C, 3×/day for 1 minute, for 5 days. Roughness and wear analysis were done in confocal laser microscope. Data were statistically analyzed (α=0.05). Results: As regards roughness, there was no statistically difference among the groups. The groups irradiated with Er:YAG had a volume loss lower. G6 showed higher values than the groups irradiated with Er:YAG and lower than the other groups. The other groups irradiated with Nd:YAG showed similar wear results to the control. Conclusions: The Er:YAG laser showed the lowest volume loss from wear analysis, suggesting the increased the acid resistance of dentin. Key words:Dentine sensitivity, Lasers, Sodium fluoride.

Investigating the association between dental age and polymorphisms in genes encoding estrogen receptors.

BACKGROUND: Genetic polymorphisms have been shown to influence several physiological traits, including dental and craniofacial characteristics. Understanding the clinical relevance of genetic polymorphisms in dental practice is crucial to personalize treatment plans and improve treatment outcomes. OBJECTIVE: to evaluate the association between dental age and genetic polymorphisms in genes encoding estrogen receptors alpha and beta (ESR1 and ESR2, respectively) in a sample of Brazilian children. METHODOLOGY: This retrospective cross-sectional study was performed with children undergoing orthodontic treatment. Patients with syndromes, congenital anomalies, craniofacial deformities, under hormonal or systemic treatment, and with a previous history of facial trauma were excluded. Panoramic radiographs were used to assess dental age according to the Demirjian, Goldstein, and Tanner method. A delta [dental age-chronological age (DA-CA)] was obtained, which shows whether the patient tends to have a normal, delayed (negative values), or advanced (positive values) dental age. DNA isolated from buccal cells was used to genotype four genetic polymorphisms: rs9340799 (A>G) and rs2234693 (C>T), located in ESR1; and rs1256049 (C>T) and rs4986938 (C>T), located in ESR2. A statistical analysis was performed and values of p<0.05 indicated statistical difference. RESULTS: A total of 79 patients were included, 44 (55.70%) girls and 35 (44.30%) boys. The Demirjian, Goldstein, and Tanner method, in general, overestimated patients' age by 0.75 years. There was no difference in the delta of dental age between the sexes (p>0.05). Genetic polymorphisms in ESR1 and ESR2 were not associated with dental age (p>0.05). CONCLUSION: The studied genetic polymorphisms in ESR1 and ESR2 were not associated with dental age in Brazilian children.

Effect of the Case for Carpule as a Visual Passive Distraction Tool on Dental Fear and Anxiety: A Pilot Study.

The present cross-over study aimed to evaluate the effect of a visual passive distraction tool, a case for carpule, in the management of fear and anxiety during invasive dental treatment. Children between the ages of 4 and 8 years that need at least two treatments with inferior alveolar nerve block were selected. All the included children received two treatments at different moments: in one treatment, local anesthesia was performed with a visual passive distraction tool, the crocodile case, for carpule (experimental); in the other treatment, local anesthesia was performed without the device (control). An evaluation of the anxiety levels was performed by measuring the heart rate and salivary cortisol levels. Wilcoxon's nonparametric test was used for a data analysis (p < 0.05). The mean heart rate with the visual passive distraction device fell from 81.8 to 78.1, while the control rose from 91.4 to 100 (p < 0.05). The mean salivary cortisol levels with the visual passive distraction device fell from 2.0 to 1.6, while in the control, they rose from 2.1 to 2.4 (p < 0.05). In conclusion, the crocodile case for carpule as a visual passive distraction device contributed positively to the management of fear and anxiety during inferior alveolar nerve block in children.

Geographic Information Systems (GIS) to Assess Dental Caries, Overweight and Obesity in Schoolchildren in the City of Alfenas, Brazil.

Childhood-related obesity and overweight are increasing concerns for the health and well-being of children. Dental caries (decay) is the most prevalent oral disease during childhood, and several studies have suggested that nutritional status and dental caries are associated in children. Therefore, this study aimed to determine the geographic distribution of childhood overweight/obesity and dental caries in a medium-sized Brazilian city. This cross-sectional study was conducted with 269 children of both genders enrolled in four public schools in the city of Alfenas. The children were clinically examined to assess cavitated dental caries and nutritional status (overweight and obesity). In addition, the GIS was used for the geospatial clustering analyses. A heat map was created by the Kemel method to estimate the concentration of the outcomes. The cavitated dental caries and overweight/obesity were also pointed out by dots on the map. However, of the 269 children, 118 were boys (43.87%) and 151 were girls (56.13%). One hundred fifty-seven children (58.4%) were classified as having "non-cavitated caries," while 112 (41.6%) were classified as having "cavitied caries." In the nutritional status assessment, 204 children (75.84%) were classified as "eutrophic," while 65 children (24.16%) were classified as "overweight/obesity," A geographical correlation of dental caries with overweight/obesity may exist in the northeast and southwest areas. In conclusion, a geographical concordance between the dental caries and the occurrence of overweight/obesity among the schoolchildren from Alfenas may exist in some areas. Future studies are necessary.

Investigating the association between dental age and polymorphisms in genes encoding estrogen receptors

Abstract Background Genetic polymorphisms have been shown to influence several physiological traits, including dental and craniofacial characteristics. Understanding the clinical relevance of genetic polymorphisms in dental practice is crucial to personalize treatment plans and improve treatment outcomes. Objective to evaluate the association between dental age and genetic polymorphisms in genes encoding estrogen receptors alpha and beta (ESR1 and ESR2, respectively) in a sample of Brazilian children. Methodology This retrospective cross-sectional study was performed with children undergoing orthodontic treatment. Patients with syndromes, congenital anomalies, craniofacial deformities, under hormonal or systemic treatment, and with a previous history of facial trauma were excluded. Panoramic radiographs were used to assess dental age according to the Demirjian, Goldstein, and Tanner method. A delta [dental age-chronological age (DA-CA)] was obtained, which shows whether the patient tends to have a normal, delayed (negative values), or advanced (positive values) dental age. DNA isolated from buccal cells was used to genotype four genetic polymorphisms: rs9340799 (A>G) and rs2234693 (C>T), located in ESR1; and rs1256049 (C>T) and rs4986938 (C>T), located in ESR2. A statistical analysis was performed and values of p<0.05 indicated statistical difference. Results A total of 79 patients were included, 44 (55.70%) girls and 35 (44.30%) boys. The Demirjian, Goldstein, and Tanner method, in general, overestimated patients' age by 0.75 years. There was no difference in the delta of dental age between the sexes (p>0.05). Genetic polymorphisms in ESR1 and ESR2 were not associated with dental age (p>0.05). Conclusion The studied genetic polymorphisms in ESR1 and ESR2 were not associated with dental age in Brazilian children.

Polyethylene terephthalate clamps: Optimization in endodontic and restorative practices.

Background: There is a growing search for innovations in dental materials and instruments and, therefore, an increase need to optimize the instruments used in the absolute isolation. The gold standard procedure contributes significantly to the quality of restorative and endodontic procedures. Thus, the aim of the present study was to evaluate the radiopacity of polyethylene terephthalate polymer clamps and compare them to conventional metal clamps. Material and Methods: The polyethylene terephthalate clamp was developed at the University of Uberaba (Patent application #PI0901719-4, Uberaba, MG, Brazil). Five polyethylene terephthalate clamps and five conventional metal clamps were used. The clamps were positioned, next to an aluminum scale, under the same phosphor plate to perform 3 radiographs. The locator cylinder was set perpendicular to the radiographic films at a focal length of 20 cm and set to 60 kVp and 0.06 seconds. After image processing, optical density values were read using DBWin 5.0.4 software. The mean of the 3 readings taken on each clamp was adopted as the radiodensity of the specimen. The differences between the groups were compared using Student's t-test (p<0.05). Results: Polyethylene terephthalate clamps demonstrated significantly lower radiopacity than conventional metal clamps (p<0.05). Conclusions: Polyethylene terephthalate clamps have lower radiopacity when compared to conventional metal clamps. Key words:Rubber Dams, Dentistry, Operative, Endodontics.

Parathyroid Hormone Gene and Genes Involved in the Maintenance of Vitamin D Levels Association with Mandibular Retrognathism.

In this study we evaluated whether single nucleotide polymorphisms (SNPs) in the genes encoding PTH, VDR, CYP24A1, and CYP27B1 were associated with mandibular retrognathism (MR). Samples from biologically-unrelated Brazilian patients receiving orthodontic treatment were included in this study. Pre-orthodontic lateral cephalograms were used to determine the phenotype. Patients with a retrognathic mandible were selected as cases and those with an orthognathic mandible were selected as controls. Genomic DNA was used for genotyping analysis of SNPs in PTH (rs694, rs6256, and rs307247), VDR (rs7975232), CYP24A1 (rs464653), and CYP27B1 (rs927650). Chi-squared or Fisher's tests were used to compare genotype and allele distribution among groups. Haplotype analysis was performed for the SNPs in PTH. The established alpha was p < 0.05. Multifactor dimensionality reduction (MDR) was used to identify SNP-SNP interactions. A total of 48 (22 males and 26 females) MR and 43 (17 males and 26 females) controls were included. The linear mandibular and the angular measurements were statistically different between MR and controls (p < 0.05). In the genotype and allele distribution analysis, the SNPs rs694, rs307247, and rs464653 were associated with MR (p < 0.05). MDR analyses predicted the best interaction model for MR was rs694-rs927650, followed by rs307247-rs464653-rs927650. Some haplotypes in the PTH gene presented statistical significance. Our results suggest that SNPs in PTH, VDR, CYP24A1, and CYP27B1 genes are associated with the presence of mandibular retrognathism.

Influence of Er,Cr:YSGG laser on root dentin submitted to erosive and/or abrasive challenges.

This study evaluated how Er,Cr:YSGG laser, associated or not with 5% fluoride varnish, influences the surface roughness and volume loss of bovine root dentin submitted to erosive and/or abrasive wear. One hundred and twenty dentin specimens were divided into the groups: without preventive treatment (WPT), 5% fluoride varnish (FV); Er,Cr:YSGG laser irradiation (L), and varnish combined with laser (FV + L). The specimens (n = 10) were subdivided into: 1 = erosion (E); 2 = abrasion (A); and 3 = erosion followed by abrasion (E + A). The erosive solution used was a soft-drink (pH = 2.42 at 4ºC) applied in 5-min cycles twice a day for 10d. Abrasive wear involved brushing for 60s with an electric brush (1,600-oscillations/s) at a load of 2.0N. Surface roughness and volume loss were evaluated using a laser scanning confocal microscope. Roughness data were submitted to one-way ANOVA and Tukey post-hoc test. For volume loss, the Kruskal-Wallis and Dunn's post-hoc tests were used (α = 5%). The lowest values of roughness were found in the control areas of all subgroups (p > 0.05). In the experimental area, the [(WPT) + (E+A)] subgroup had a significantly higher roughness (5.712 ± 0.163 µm 2 ) than the other subgroups (p < 0.05). The L and (FV + L) groups had statistically similar roughness, regardless of the type of wear. The (FV + L) group had the lowest volume loss, regardless of the type of wear performed: [(FV + L) + (E)] = 7.5%, [(FV + L) + (A) = 7.3%, and [(FV + L) + (E + A)] = 8.1%. The subgroup [(WPT) + (E + A)] had the highest volume loss (52.3%). The proposed treatments were effective in controlling dentin roughness. Laser irradiation can be an effective method to increase root dentin resistance after challenges and limit problems related to non-carious lesions.

Influence of Er, Cr: YSGG laser on root dentin submitted to erosive and/or abrasive challenges

Abstract This study evaluated how Er,Cr:YSGG laser, associated or not with 5% fluoride varnish, influences the surface roughness and volume loss of bovine root dentin submitted to erosive and/or abrasive wear. One hundred and twenty dentin specimens were divided into the groups: without preventive treatment (WPT), 5% fluoride varnish (FV); Er,Cr:YSGG laser irradiation (L), and varnish combined with laser (FV + L). The specimens (n = 10) were subdivided into: 1 = erosion (E); 2 = abrasion (A); and 3 = erosion followed by abrasion (E + A). The erosive solution used was a soft-drink (pH = 2.42 at 4ºC) applied in 5-min cycles twice a day for 10d. Abrasive wear involved brushing for 60s with an electric brush (1,600-oscillations/s) at a load of 2.0N. Surface roughness and volume loss were evaluated using a laser scanning confocal microscope. Roughness data were submitted to one-way ANOVA and Tukey post-hoc test. For volume loss, the Kruskal-Wallis and Dunn's post-hoc tests were used (α = 5%). The lowest values of roughness were found in the control areas of all subgroups (p > 0.05). In the experimental area, the [(WPT) + (E+A)] subgroup had a significantly higher roughness (5.712 ± 0.163 μm 2 ) than the other subgroups (p < 0.05). The L and (FV + L) groups had statistically similar roughness, regardless of the type of wear. The (FV + L) group had the lowest volume loss, regardless of the type of wear performed: [(FV + L) + (E)] = 7.5%, [(FV + L) + (A) = 7.3%, and [(FV + L) + (E + A)] = 8.1%. The subgroup [(WPT) + (E + A)] had the highest volume loss (52.3%). The proposed treatments were effective in controlling dentin roughness. Laser irradiation can be an effective method to increase root dentin resistance after challenges and limit problems related to non-carious lesions.

A Utilização da Laserterapia para o Tratamento da Hipersensibilidade Dentinária: Revisão da Literatura / Laser Therapy in the Treatment of Dentin Hypersensitivity: Literature Review

A hipersensibilidade dentinária - HD é caracterizada por uma dor aguda, de curta duração, causada pela movimentação de fluidos no interior de túbulos dentinários expostos ao meio bucal. Recentemente, a utilização dos lasers de alta e baixa intensidade foi proposta como uma alternativa para o tratamento da HD. Este trabalho realizou uma revisão da literatura baseada em artigos publicados entre 2009 e 2016 sobre os efeitos dos lasers de baixa e alta intensidade para o tratamento da HD. A base de dados utilizada foi o PubMed utilizando-se os descritores: Dentin hypersensitivity, laser, Nd:YAG, Er:YAG, GaAlAs, Er,Cr:YSGG, CO2 , HeNe, e hydrodinamic theory. Foi observado que o tratamento da HD com lasers é um método biocompatível, não-invasivo e eficiente. Os lasers de baixa intensidade (HeNe e GaAlAs) estimulam as células nervosas do tecido pulpar, interferindo na polaridade das membranas celulares, pelo aumento da amplitude do potencial de ação. Esta ação leva ao bloqueio da transmissão do estímulo ao sistema nervoso central e estimula os odontoblastos a produzirem dentina reparadora, o que diminui a permeabilidade da dentina e interrompe a movimentação de fluidos nos túbulos dentinários. Os lasers em alta intensidade (Nd:YAG, Er:YAG, Er,Cr:YSGG e CO2) têm o objetivo de obliterar a embocadura dos túbulos dentinários, através da irradiação direta da dentina exposta ao meio bucal, promovendo a dissolução e a ressolidificação dos cristais de hidroxiapatita da dentina, levando à eliminação da sensibilidade dolorosa por um tempo prolongado. Pode-se concluir que os lasers de alta e baixa intensidade são efetivos para o tratamento da hipersensibilidade dentinária cervical.

Dentin hypersensitivity - DH is characterized by an acute and short-duration pain caused by the movement of fluids into the dentinal tubules that are exposed to the oral environment. Recently, the use of lasers has been proposed as an alternative for the treatment of DH. This study conducted a literature review based on papers published between 2009 and 2016 about the use of low and high intensity lasers for the treatment of HD. The database PubMed was consulted, using the following keywords: dentin hypersensitivity, laser, Nd : YAG, Er:YAG, GaAlAs, Er, Cr:YSGG, CO2 , HeNe, and hydrodinamic theory. It was observed that the treatment of DH with lasers can be a biocompatible, non-invasive, and efficient method. The low-intensity lasers (HeNe and GaAlAs) stimulate nerve cells in the pulp tissue, interfering with the polarity of the cell membranes by increasing the amplitude of the action potential, that inhibits the transmission of stimuli to the central nervous system. It stimulates the odontoblasts to produce reparative dentine, which decreases dentin permeability and impairs the movement of fluids into the dentinal tubules. The high-intensity lasers (Nd:YAG, Er:YAG, Er,Cr:YSGG and CO2) obliterate the dentinal tubules by direct irradiation of dentin that is exposed to the oral environment, promoting the dissolution and resolidification of hydroxyapatite crystals, leading to elimination of pain sensitivity for a long period. It can be concluded that the high and low intensity lasers are effective for the treatment of cervical dentine hypersensitivity

Evaluation of bond strength and thickness of adhesive layer according to the techniques of applying adhesives in composite resin restorations.

Adhesive restorations have increasingly been used in dentistry, and the adhesive system application technique may determine the success of the restorative procedure. The aim of this study was to evaluate the influence of the application technique of two adhesive systems (Clearfil SE Bond and Adper Scotchbond MultiPurpose) on the bond strength and adhesive layer of composite resin restorations. Eight human third molars were selected and prepared with Class I occlusal cavities. The teeth were restored with composite using various application techniques for both adhesives, according to the following groups (n = 10): group 1 (control), systems were applied and adhesive was immediately light activated for 20 seconds without removing excesses; group 2, excess adhesive was removed with a gentle jet of air for 5 seconds; group 3, excess was removed with a dry microbrushtype device; and group 4, a gentle jet of air was applied after the microbrush and then light activation was performed. After this, the teeth were submitted to microtensile testing. For the two systems tested, no statistical differences were observed between groups 1 and 2. Groups 3 and 4 presented higher bond strength values compared with the other studied groups, allowing the conclusion that excess adhesive removal with a dry microbrush could improve bond strength in composite restorations. Predominance of adhesive fracture and thicker adhesive layer were observed via scanning electron microscopy (SEM) in groups 1 and 2. For groups 3 and 4, a mixed failure pattern and thinner adhesive layer were verified. Clinicians should be aware that excess adhesive may negatively affect bond strength, whereas a thin, uniform adhesive layer appears to be favorable.

Surface and subsurface erosion of primary enamel by acid beverages over time.

This study evaluated the influence of a cola-type soft drink and a soy-based orange juice on the surface and subsurface erosion of primary enamel, as a function of the exposure time. Seventy-five primary incisors were divided for microhardness test (n=45) or scanning electron microscopy (SEM) analysis (n=30). The specimens were randomly assigned to 3 groups: 1 - artificial saliva (control); 2 - cola-type soft drink; and 3 - soy-based orange juice. Immersion cycles in the beverages were undertaken under agitation for 5 min, 3 times a day, during 60 days. Surface microhardness was measured at 7, 15, 30, 45 and 60 days. After 60 days, specimens were bisected and subsurface microhardness was measured at 30, 60, 90, 120, 150 and 200 µm from the surface exposed. Data were analyzed by ANOVA and Tukey's test (a=0.05). Groups 2 and 3 presented similar decrease of surface microhardness. Regarding subsurface microhardness, group 2 presented the lowest values. SEM images revealed that after 60 days the surfaces clearly exhibited structural loss, unlike those immersed in artificial saliva. It may be concluded that erosion of the surfaces exposed to the cola-type soft drink was more accentuated and directly proportional to the exposure time.

Surface and subsurface erosion of primary enamel by acid beverages over time

This study evaluated the influence of a cola-type soft drink and a soy-based orange juice on the surface and subsurface erosion of primary enamel, as a function of the exposure time. Seventy-five primary incisors were divided for microhardness test (n=45) or scanning electron microscopy (SEM) analysis (n=30). The specimens were randomly assigned to 3 groups: 1 - artificial saliva (control); 2 - cola-type soft drink; and 3 - soy-based orange juice. Immersion cycles in the beverages were undertaken under agitation for 5 min, 3 times a day, during 60 days. Surface microhardness was measured at 7, 15, 30, 45 and 60 days. After 60 days, specimens were bisected and subsurface microhardness was measured at 30, 60, 90, 120, 150 and 200 µm from the surface exposed. Data were analyzed by ANOVA and Tukey’s test (a=0.05). Groups 2 and 3 presented similar decrease of surface microhardness. Regarding subsurface microhardness, group 2 presented the lowest values. SEM images revealed that after 60 days the surfaces clearly exhibited structural loss, unlike those immersed in artificial saliva. It may be concluded that erosion of the surfaces exposed to the cola-type soft drink was more accentuated and directly proportional to the exposure time.

Este estudo avaliou a influência de um refrigerante a base de cola e um suco de laranja a base de soja na erosão da superfície e subsuperfície do esmalte do dente decíduo, em função do tempo de exposição. Setenta e cinco incisivos decíduos foram divididos para o teste de microdureza (n=45) ou para a análise em microscópio eletrônico de varredura (MEV) (n=30). Os espécimes foram alocados aleatoriamente em 3 grupos: I - saliva artificial (controle); II - refrigerante a base de cola; e III - suco de laranja a base de soja. Ciclos de imersão nas bebidas foram realizados sob agitação durante 5 min, 3 vezes ao dia, durante 60 dias. A microdureza superficial foi mensurada aos 7, 15, 30, 45 e 60 dias. Após 60 dias, os espécimes foram seccionados e a microdureza subsuperficial foi mensurada aos 30, 60, 90, 120, 150 e 200 μm. Os dados foram analisados pelos testes ANOVA e Tukey (α=5 por cento). Os grupos II e III apresentam uma diminuição similar da microdureza superficial. O grupo II apresentou menores valores de microdureza subsuperficial. As imagens de MEV revelaram que após 60 dias as superficies mostraram perdas de estruturas claramentes identificadas, diferentemente das superfícies imersas em saliva artificial. Pode-se concluir que a erosão das superficies expostas ao refrigerante a base de cola foi mais acentuada e diretamente proporcional ao tempo de exposição à bebida.

Effect of surface treatment and storage on the bond strength of different ceramic systems

Aim: The aim of this study was to evaluate the micro shear bond strength of different ceramic systems – IPS Empress 2, Cergogold, In-Ceram Alumina and Cercon - and a dual luting agent. Methods: Twelve specimens of each ceramic were fabricated and divided according different surface treatments: Group 1: No additional treatment was applied to the ceramic surface; Group 2: Ceramics were etched with 9.5% hydrofluoric acid; Group 3: specimens treated with airborne particle abrasion for each ceramic system in accordance with manufacturer’s instructions (n=20). The tests were performed after 24 h or after water storage for 6 months. Data were then assessed statistically using the 3-way ANOVA and the Tukey’s test (P<0.05). Results: For Cergogold and IPS Empress 2 systems, the treatments performed with airborne particle abrasion and hydrofluoric acid showed no significant differences from each other, and both were superior to the groups without treatment. For Cercon and In-Ceram ceramics, no differences were found among the groups (P<0.05). When the surface was treated with hydrofluoric acid, the highest bond strength was found to IPS Empress 2 in the 6-month storage period (P<0.05). Conclusion: Lower bond strength values were only observed with IPS Empress 2 ceramic for the control group in the 6-month storage (P<0.05).

O condicionamento ácido prévio ainda é indispensável para a odontologia adesiva? / Is previous total etching still indispensable for the adhesive dentistry?

O objetivo deste trabalho foi avaliar as características dos sistemas adesivos disponíveis atualmente considerando a aplicação ou não do condicionamento prévio com ácido fosfórico. O conhecimento das estruturas e o tratamento adequado do substrato dental são fundamentais para utilização dos adesivos convencionais. Os sistemas adesivos autocondicionantes possuem técnica simplificada dispensando o condicionamento ácido prévio. O profissional deverá ter conhecimento dos mecanismos de adesão ao substrato dental, experiência clínica e domínio da técnica de aplicação do adesivo escolhido. O condicionamento ácido prévio não deve ser considerado indispensável na Odontologia adesiva atual.

Bond strength of a pit-and-fissure sealant associated to etch-and-rinse and self-etching adhesive systems to saliva-contaminated enamel: individual vs. simultaneous light curing.

This study evaluated in vitro the shear bond strength (SBS) of a resin-based pit-and-fissure sealant [Fluroshield (F), Dentsply/Caulk] associated with either an etch-and-rinse [Adper Single Bond 2 (SB), 3M/ESPE] or a self-etching adhesive system [Clearfil S3 Bond (S3), Kuraray Co., Ltd.] to saliva-contaminated enamel, comparing two curing protocols: individual light curing of the adhesive system and the sealant or simultaneous curing of both materials. Mesial and distal enamel surfaces from 45 sound third molars were randomly assigned to 6 groups (n=15), according to the bonding technique: I - F was applied to 37% phosphoric acid etched enamel. The other groups were contaminated with fresh human saliva (0.01 mL; 10 s) after acid etching: II - SB and F were light cured separately; III - SB and F were light cured together; IV - S3 and F were light cured separately; V - S3 and F were light cured simultaneously; VI - F was applied to saliva-contaminated, acid-etched enamel without an intermediate bonding agent layer. SBS was tested to failure in a universal testing machine at 0.5 mm/min. Data were analyzed by one-way ANOVA and Fisher's test (alpha=0.05).The debonded specimens were examined with a stereomicroscope to assess the failure modes. Three representative specimens from each group were observed under scanning electron microscopy for a qualitative analysis. Mean SBS in MPa were: I-12.28 (+/-4.29); II-8.57 (+/-3.19); III-7.97 (+/-2.16); IV-12.56 (+/-3.11); V-11.45 (+/-3.77); and VI-7.47 (+/-1.99). In conclusion, individual or simultaneous curing of the intermediate bonding agent layer and the resin sealant did not seem to affect bond strength to saliva-contaminated enamel. S3/F presented significantly higher SBS than the that of the groups treated with SB etch-and-rinse adhesive system and similar SBS to that of the control group, in which the sealant was applied under ideal dry, noncontaminated conditions.

Bond strength of a pit-and-fissure sealant associated to etch-and-rinse and self-etching adhesive systems to saliva-contaminated enamel: individual vs. simultaneous light curing

This study evaluated in vitro the shear bond strength (SBS) of a resin-based pit-and-fissure sealant [Fluroshield (F), Dentsply/Caulk] associated with either an etch-and-rinse [Adper Single Bond 2 (SB), 3M/ESPE] or a self-etching adhesive system [Clearfil S3 Bond (S3), Kuraray Co., Ltd.] to saliva-contaminated enamel, comparing two curing protocols: individual light curing of the adhesive system and the sealant or simultaneous curing of both materials. Mesial and distal enamel surfaces from 45 sound third molars were randomly assigned to 6 groups (n=15), according to the bonding technique: I - F was applied to 37 percent phosphoric acid etched enamel. The other groups were contaminated with fresh human saliva (0.01 mL; 10 s) after acid etching: II - SB and F were light cured separately; III - SB and F were light cured together; IV - S3 and F were light cured separately; V - S3 and F were light cured simultaneously; VI - F was applied to saliva-contaminated, acid-etched enamel without an intermediate bonding agent layer. SBS was tested to failure in a universal testing machine at 0.5 mm/min. Data were analyzed by one-way ANOVA and Fisher's test (α=0.05).The debonded specimens were examined with a stereomicroscope to assess the failure modes. Three representative specimens from each group were observed under scanning electron microscopy for a qualitative analysis. Mean SBS in MPa were: I-12.28 (±4.29); II-8.57 (±3.19); III-7.97 (±2.16); IV-12.56 (±3.11); V-11.45 (±3.77); and VI-7.47 (±1.99). In conclusion, individual or simultaneous curing of the intermediate bonding agent layer and the resin sealant did not seem to affect bond strength to saliva-contaminated enamel. S3/F presented significantly higher SBS than the that of the groups treated with SB etch-and-rinse adhesive system and similar SBS to that of the control group, in which the sealant was applied under ideal dry, noncontaminated conditions.

Este estudo avaliou in vitro a resistência ao cisalhamento (RC) de um selante resinoso [Fluroshield (F), Dentsply/Caulk] em associação com um sistema adesivo de condicionamento total [Adper Single Bond 2 (SB), 3M/ESPE] ou auto-condicionante [Clearfil S3 Bond (S3), Kuraray Co., Ltd.] após contaminação salivar do esmalte, comparando dois protocolos: fotopolimerização individual do sistema adesivo e do selante ou simultânea de ambos os materiais. Superfícies mesiais e distais de esmalte de 45 terceiros molares hígidos foram aleatoriamente alocadas em 6 grupos (n=15), de acordo com a técnica adesiva empregada: I - F foi aplicado sobre o esmalte condicionado com ácido fosfórico a 37 por cento. Os demais grupos foram contaminados com saliva (0,01 mL por 10 s) após o condicionamento ácido. II - SB e F foram fotopolimerizados separadamente; III - SB e F foram fotopolimerizados simultaneamente; IV - S3 e F foram fotopolimerizados separadamente; V - S3 e F foram fotopolimerizados simultaneamente; VI - F foi aplicado sobre o esmalte condicionado e contaminado sem sistema adesivo. RC foi testada em uma máquina universal de ensaios (0,5 mm/min; 50 kgf) e os dados analisados por ANOVA a 1 fator e teste exato de Fisher (α=0,05). As interfaces adesivas foram analisadas quanto ao padrão de fraturas em estereomicroscópio. Três espécimes de cada grupo foram analisados qualitativamente em microscópio eletrônico de varredura. As médias de RC em MPa foram: I-12,28 (±4,29); II-8,57 (±3,19); III-7,97 (±2,16); IV-12,56 (±3,11); V-11,45 (±3,77); e VI-7,47 (±1,99). Conclui-se que a fotopolimerização individual ou simultânea do sistema adesivo e do selante não afetou os valores de RC ao esmalte contaminado. S3/F apresentou RC estatisticamente maior do que os grupos tratados com o sistema adesivo etch-and-rinse SB e estatisticamente semelhante ao grupo controle, no qual o selante foi aplicado em condições ideais, na ausência de contaminação salivar.

Técnicas alternativas para amenizar os efeitos gerados durante a contração da resina composta / Alternative technique to minimize the effects caused by the shrinkage of the composite resin

O objetivo deste trabalho foi aplicar técnicas alternativas de inserção e fotoativação de resina com o intuito de amenizar os efeitos da contração de polimerização, avaliando a infiltração marginal. Foram confeccionadas cavidades de classe V, com margem cervical em dentina, restauradas com o sistema restaurador Single Bond/Z250. Os dentes foram divididos em quatro grupos, de acordo com a técnica de inserção da resina (incremental ou em incremento único) e formas de fotoativação (máxima intensidade ou gradual). As técnicas de inserção incremental e fotoativação gradual, quando associadas, diminuíram os efeitos gerados durante a contração de polimerização da resina