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SUMMARY Purpose: This study aimed to characterize and analyze the number of voids and the percentage of void volume within and between the layers of class II composite restorations made using the bulk fill technique or the incremental technique by optical coherence tomography (OCT). Methods and Materials: Class II cavities (4×4×2 mm) were prepared in 48 human third molars (n=24 restorations per group, two class II cavities per tooth). Teeth were divided into four groups and restored as follows: group 1 (FOB), bulk filled in a single increment using Filtek One Bulk Fill (3M Oral Care); group 2 (FXT), incrementally filled using four oblique layers of Filtek Z350 XT (3M Oral Care); group 3 (FBF+FXT), bulk filled in a single increment using Filtek Bulk Fill Flowable Restorative (3M Oral Care) covered with two oblique layers of Filtek Z350 XT (3M Oral Care), and group 4 (FF+FXT), incrementally filled using Filtek Z350 XT Flow (3M Oral Care) covered with two oblique layers of Filtek Z350 XT (3M Oral Care). After the restorative procedure, specimens were immersed into distilled water and stored in a hot-air oven at 37°C. Forty-eight hours later, thermal cycling was conducted (5000 cycles, 5°C to 55°C). Afterward, OCT was used to detect the existence of voids and to calculate the number of voids and percentage of voids volume within each restoration. Data were submitted to chi-square and Kruskal-Wallis tests (α=0.05). Comparisons were made using the Dunn method. Results: Voids were detected in all groups, ranging from 0.000002 (FBF+FXT and FF+FXT) to 0.32 mm3 (FBF+FXT). FF + FXT presented voids in all of the restorations and had a significantly higher number of voids per restoration when compared to the other groups (p Conclusions: The use of flowable resin-based composites can result in an increased number of voids and percentage of voids volume in restorations, and this appears to be more related to voids present inside the syringe of the material than to the use of incremental or bulk fill restorative techniques.

SUMMARY Objectives: This study evaluated the effect of toothbrushing with a dentifrice on gloss, roughness profile, surface roughness, and wear of conventional and bulk-fill resin-based composites. Methods and Materials: Gloss and surface roughness of resin-based composites (RBCs; Admira Fusion X-tra, Aura Bulk Fill, Filtek Bulk Fill Flowable, Filtek Bulk Fill Posterior Restorative, Filtek Supreme Ultra, Herculite Ultra, Mosaic Enamel, SDR flow+, Sonic Fill 2, Tetric EvoFlow Bulk Fill and Tetric EvoCeram Bulk Fill) were analyzed before and after brushing; the roughness profile and wear were also determined after toothbrushing. Representative three-dimensional images of the surface loss and images comparing the unbrushed and brushed surfaces were also compared. Analysis of variance and Tukey post hoc tests were applied (α=0.05) to the gloss, surface roughness, roughness profile, and surface loss data. Pearson's correlation test was used to determine the correlation between gloss and surface roughness, surface loss and percentage of gloss decrease after brushing, and surface loss and surface roughness after brushing. Results: For all RBCs tested after 20,000 brushing cycles, the gloss was reduced and the surface roughness increased (p Conclusions: Toothbrushing with a dentifrice reduced the gloss, increased the surface roughness, and caused loss at the surface of all the RBCs tested. Considering all the properties tested, Mosaic Enamel exhibited excellent gloss retention and a low roughness profile and wear, while Admira Fusion X-tra exhibited the greatest decrease in gloss, the highest roughness profile, and the most wear.

OBJECTIVE To evaluate coating materials regarding color and roughness changes when applied over a composite resin. MATERIALS AND METHODS Specimens were made using Filtek Supreme Ultra. Coating materials were applied over the specimens' surface: Control (CTRL); Adper Single Bond Plus (SB); Scotchbond Universal (US); Clearfil SE (CL); Ambar APS (APS); Bioforty (BF); Fortify (FF); PermaSeal (PS); G-CoatPlus (GC). Specimens were evaluated regarding color changes (∆E00 ) using spectrophotometer (n = 10); surface roughness (Ra), using optical profilometer (n = 10); surface topography, using scanning electron microscopy (n = 1); and thickness of material, using optical microscopy (n = 1). Analyses were made before and after 24, 72, and 168 hours of storage in wine, used as a staining solution. Data was statistically analyzed using analysis of variance, Tukey and Pearson tests (α:.05). RESULTS None of the materials presented color stability. ∆E00 increased with increasing storage time at red wine, until 72 hours. BF, FF, PS, SB, and CTRL presented the lowest ∆E00 after 24 hours. APS presented the highest ∆E00 (32.59; P

To determine the potential effect of four different light curing units (LCUs) on the curing profile of two bulk fill resin-based composites (RBCs).Four LCUs (Bluephase 20i, Celalux 3, Elipar DeepCure-S and Valo Grand) were used to light cure two RBCs (Filtek Bulk Fill Posterior Restorative and Tetric EvoCeram Bulk Fill). The effective tip diameter, radiant power, radiant emittance, emission spectrum and light beam profile of the LCUs were measured. Knoop microhardness was measured at the top and bottom surfaces of RBC specimens that were 12-mm in diameter and 4-mm deep (n=5). The distribution of the spectral radiant power that was delivered to the surface of the specimen and the light transmission through the 4-mm thick specimens was measured using an integrating sphere. Two-way ANOVA and Tukey tests (α=0.05) were applied.The Valo Grand produced the most homogeneous microhardness across the surfaces of the RBCs (p0.05). When the Celalux 3, Bluephase 20i and Elipar DeepCure-S lights were used, the center of the specimens achieved greater hardness values compared to their outer regions (p0.05). Approximately 10% of the radiant power delivered to the top reached the bottom of the specimen, although almost no violet light passed through 4mm of either RBC. A positive correlation was observed between the radiant exposure and microhardness.The characteristics of the LCUs influenced the photoactivation of the RBCs. The use of a wide tip with a homogeneous light distribution is preferred when light curing RBCs using a bulk curing technique.

Objectives To determine the effects of tooth brushing on five bulk-fill resin based composites (RBCs). Method Ten samples of Filtek Supreme Enamel (control), Filtek One Bulk Fill, Tetric EvoCeram Bulk Fill, SonicFill 2, SDR flow+, and Admira Fusion X-tra were light cured for 20 seconds using the Valo Grand curing light. After 24 hours storage in air at 37°C, specimens were brushed in a random order using Colgate OpticWhite dentifrice and a soft toothbrush. Surface gloss was measured prior to brushing, after 5,000, 10,000 and 15,000 back and forth brushing cycles. Surface roughness was measured after 15,000 brushing cycles using atomic force microscopy (AFM) and selected scanning electron microscope (SEM) images were taken. The data was examined using ANOVA and pair-wise comparisons using Scheffe's post-hoc multiple comparison tests (α = 0.05). Results Surface gloss decreased and the surface roughness increased after brushing. Two-way ANOVA showed that both the RBC and the number of brushing cycles had a significant negative effect on the gloss. One-way ANOVA showed that the RBC had a significant effect on the roughness after 15,000 brushing cycles. For both gloss and roughness, brushing had the least effect on the nano-filled control and nano-filled bulk-fill RBC, and the greatest negative effect on Admira Fusion X-tra. The SEM images provided visual agreement. There was an excellent linear correlation (R2 = 0.98) between the logarithm of the gloss and roughness. Conclusion After brushing, the bulk-fill RBCs were all rougher than the control nano-filled RBC. The nano-filled bulk-fill RBC was the least affected by brushing. Clinical significance Bulk-fill RBCs lose their gloss faster and become rougher than the nanofilled conventional RBC, Filtek Supreme Ultra. The nanofilled bulk-fill RBC was the least affected by tooth brushing.

Light Curing Units (LCUs) are used daily in almost every dental office to photocure resins, but because the light is so bright, the user is unable to tell visually if there are any differences between different LCUs. This study evaluated the light output from six dental LCUs: Elipar Deep Cure-S (3M ESPE), Bluephase G2 (Ivoclar Vivadent), Translux 2Wave (Heraeus Kulzer), Optilight Prime (Gnatus), Slim Blast (First Medica) and Led.B (Guilin Woodpecker) with a fully charged battery, after 50, and again after 100, 20second light exposures. For each situation, the radiant power was measured 10 times with a laboratory-grade power meter. Then, the emission spectrum was measured using a fiber-optic spectrometer followed by an analysis of the light beam profile. It was found there were significant differences in the LCU power and the irradiance values between the LCUs (p

Objetivo: avaliar a dureza de uma resina composta fotoativada com dois métodos diferentes, contínuo e soft-start, por meio da variação da distância entre a ponta fotoativadora e a resina composta (7 mm e 0 mm). Materiais e métodos: Foram confeccionados 20 corpos-de-prova, nos quais a superfície irradiada e a oposta foram analisadas, totalizando 40 superfícies divididas em quatro grupos (n = 10): Grupo 1, método contínuo + superfície irradiada; Grupo 2, método contínuo + superfície oposta; Grupo 3, método soft-start + superfície irradiada; Grupo 4, método soft-start + superfície oposta. Os corpos-de-prova foram confeccionados com o auxílio de matrizes pretas de polipropileno, com 4 mm de diâmetro e 2 mm de espessura, utilizando a resina composta Z350 (3M ESPE) na cor AO3 e o fotoativador Elipar Freelight 2 (3M ESPE). Os corpos-de-prova foram submetidos ao teste de microdureza Vickers, no microdurômetro HMV- 2000 (Shimadzu). Foram realizados cinco entalhes por superfície, com carga de 50 gf por 45 segundos. Para a análise estatística, foram realizados os testes de ANOVA e Tukey. Resultados: Não foi encontrada diferença estatisticamente significante entre os métodos avaliados nas superfícies irradiadas. Entretanto, nas superfícies opostas, houve diferença entre os protocolos, sendo que o soft-start obteve menores valores de dureza. Quando comparadas as diferentes profundidades, houve redução nos valores de dureza para ambos os métodos de fotoativação, de forma que a porcentagem de dureza máxima de 80% não foi atingida na superfície oposta à irradiada. Relevância: O cirurgião-dentista, em sua prática clínica, deve atentar para o método de fotoativação de suas restaurações, visto que este pode prejudicar a qualidade da polimerização de resinas compostas, especialmente na profundidade de 2 mm em resinas opacas. Objective: to evaluate the hardness of a composite resin polymerized with two different methods, continuous and soft-start, by varying the distance between the activator tip and the composite resin (7 mm and 0 mm). Materials and Methods: Twenty test specimens were fabricated, in which the irradiated and the opposite surfaces were analyzed, totaling 40 surfaces divided into 4 groups (n = 10): Group 1, continuous method + irradiated surface; Group 2, continuous method + opposite surface; Group 3, soft-start method + irradiated surface; Group 4, soft-start method + opposite surface. The test specimens were prepared using black polypropylene matrices, with a diameter of 4 mm and thickness of 2 mm, Z350 composite resin (3M ESPE), shade AO3, and the Elipar Freelight 2 curing unit (3M ESPE). The test specimens were subjected to the Vickers hardness test in an HMV-2000 microhardness tester (Shimadzu). Five indentations were made per surface with a load of 50 gf for 45 seconds. The ANOVA and Tukey tests were used for the statistical analysis. Results: No statistically signifi cant difference between the evaluated methods was found in the irradiated surfaces; however, in the opposite surfaces, there were differences between protocols, in that the soft-start protocol achieved the lowest hardness values. When comparing the different depths, there was a reduction in hardness values for both activation methods, so that the maximum hardness percentage of 80% was not achieved in the opposite surface. Relevance: The dentist should be knowledgeable of the photoactivation method applied to his/her restorations, since it may reduce the polymerization quality, especially in depths of 2 mm when using opaque resins.