No abstract

ABSTRACT:The purpose of this study was to measure mass loss and surface roughness changes of different brands of flowable resin composites after a simulated toothbrushing test. The null hypotheses were that there would be no differences in mass loss and no significant changes in surface roughness after this test and that there would be no correlation between the two variables. The tested materials were Aeliteflo (Bisco), Flow-It (Pentron), Flow-It LF (Pentron), Natural Flow (DFL) and Wave (SDI). Z100 (3M/ESPE) microhybrid and Silux Plus (3M/ESPE) microfilled resin composites were used as control materials. Twelve specimens (5 mm in diameter, 3 mm thick) of each material were prepared according to manufacturers' instructions. Toothbrushing abrasion was performed on all specimens from each of the materials using a simulator. The percentage mass loss and surface roughness were assessed before and after 100,000 brushstrokes, using a Sartorius analytical balance of 0.0001 g accuracy and a Hommel Tester T1000, respectively. The measurements of both properties were statistically compared by paired t-test and Tukey's test (p < 0.05). All materials presented a statistically significant mass loss comparing initial and final values, with the exception of Flow-It LF. However, no difference was revealed when comparing the mass loss of the different tested materials. All materials became rougher and Wave presented statistically higher roughness compared to the other resin composites. Flowable resin composites did not seem to be superior to the control groups, and they can be expected to wear by mass loss and to have an increased roughness of surface after toothbrushing action. The anticipated null hypotheses were partially accepted. DESCRIPTORS: Composite resins; Tooth abrasion; Surface properties; Toothbrushing. RESUMO:O objetivo deste estudo foi mensurar a perda de massa e as alterações de rugosidade superficial de diferentes marcas de resinas compostas "flow" após teste de escovação simulada. A hipótese nula testada foi de que não haveria diferença de massa e rugosidade de superfície após o teste e de que não haveria correlação entre essas variáveis. Os materiais testados foram: Aeliteflo (Bisco), Flow-It (Pentron), Flow-It LF (Pentron), Natural Flow (DFL) e Wave (SDI). As resinas compostas Z100 (3M/ESPE) e Silux Plus (3M/ESPE) foram utilizadas como controle. Doze espécimes (5 mm de diâmetro, 3 mm de espessura) de cada material foram confeccionados de acordo com as instruções do fabricante. O teste foi conduzido em uma máquina de escovação simulada, em todos os espécimes de todos os materiais, totalizando 100.000 ciclos. Antes e depois do teste, a massa e a rugosidade de cada material foram aferidas por uma balança analítica Sartorius de 0,0001 g de precisão e pelo equipamento Hommel Tester T1000, respectivamente. Os valores obtidos foram comparados pelos testes t-pareado e Tukey (p < 0,05). Todos os materiais apresentaram diferenças estatísticas de perda de massa entre os valores iniciais e finais, com exceção da resina F...

The aim of this study was to determine oxygen saturation levels in the dental pulp of maxillary premolars in different age groups. A total of 120 human maxillary premolars with normal dental pulps were selected covering the following age groups: 20-24, 25-29, 30-34, 35-39 and 40-44 years (n=24 each group). Oxygen saturation was assessed using pulse oximetry. Analysis of variance was used to assess differences in oxygen saturation levels and Tukey's test was used to identify the age groups that differed from each other. Significance was set at 0.05. Mean oxygen saturation of 120 premolars was 86.20% considering all age groups. Significantly reduced levels were found in the oldest group compared to the other groups: 40 to 44 years -80.00% vs. 89.71, 87.67, 88.71, and 84.80% for age groups 20-24, 25-29, 30-34, 35-39 years, respectively. The mean oxygen saturation levels were similar between 20 and 39 years of age (86.20%) in the whole sample, but reduced significantly in the 40-44-year age group, suggesting that older patients present lower oxygen saturation results even in the absence of pulp tissue injury.

Tooth bleaching is a technique of choice to obtain a harmonious smile, but bleaching agents may damage the dental pulp.Objective:This study evaluated the inflammatory responses of human dental pulp after the use of two bleaching techniques.Material and Methods:Pulp samples were collected from human third molars extracted for orthodontic reasons and divided into three groups: control - no tooth bleaching (CG) (n=7); at-home bleaching with 15% carbamide peroxide (AH) (n = 10), and in-office bleaching with 38% hydrogen peroxide (IO) (n=12). Pulps were removed and stained with hematoxylin-eosin for microscopic analysis of inflammation intensity, collagen degradation, and pulp tissue organization. Immunohistochemistry was used to detect mast cells (tryptase+), blood vessels (CD31+), and macrophages (CD68+). Chi-square, Kruskal-Wallis, and Mann Whitney tests were used for statistical analysis. The level of significance was set at p<.05.Results:The inflammation intensity and the number of macrophages were significantly greater in IO than in AH and CG (p<0.05). The results of CD31+ (blood vessels per mm2) were similar in CG (61.39±20.03), AH (52.29±27.62), and IO (57.43±8.69) groups (p>0.05). No mast cells were found in the pulp samples analyzed.Conclusion:In-office bleaching with 38% hydrogen peroxide resulted in more intense inflammation, higher macrophages migration, and greater pulp damage then at-home bleaching with 15% carbamide peroxide, however, these bleaching techniques did not induce migration of mast cells and increased the number of blood vessels.

Background Immediate dentin sealing implies applying an adhesive system to dentin directly after tooth preparation, before impression. The technique is universal (inlays, onlays, veneers, crowns) and well documented clinically and experimentally. Different types of dentin bonding agents (DBAs) are available on the market. Major differences lie in the thickness of the hybrid layer and overlaying adhesive resin (filled vs. unfilled/lightly filled adhesives). Objective The objective of this work is to provide precise clinical instructions and present new experimental data about the bond strength of five DBAs (Optibond FL, Scotchbond MP, Single Bond Plus, Clearfil SE Bond, and Scotchbond Universal) used conventionally (dentin sealed at the time of restoration delivery) or with immediate dentin sealing, as well as with an additional flowable resin coating. Methods Seventy‐five human molars were selected, restored/tested according the microtensile bond strength method. Fifteen groups (n=5) were obtained from the combination of the five DBAs and three application modes: delayed dentin sealing, immediate dentin sealing and immediate dentin sealing with flowable resin coating. Results It appears that immediate dentin sealing was confirmed to significantly improve the bond strength of all tested adhesives. The use of a flowable resin coating reinforcement after immediate dentin sealing increased the microtensile bond strength of all unfilled/lightly filled adhesives (from 233% of increase for ScotchBond MP, up to 560% for Clearfil SE Bond) and maintained the performance of the 3‐step golden standard adhesive. Optibond FL used with (52.51 MPa) or without (54.75 MPa) additional flowable resin coating and Clearfil SE Bond (45.64 MPa) used with flowable resin coating provided the best results. Clinical Significance The original immediate dentin sealing (IDS) technique implies the use of a filled DBA. With unfilled/lightly filled adhesives, it is suggested to reinforce IDS with an additional flowable resin coating. This seems especially paramount to the performance of simplified adhesive systems to protect the thin bonding interface from oxygen inhibition and preserve IDS layer during predelivery cleaning of the preparation. The clinical reinforcement of unfilled/lightly filled IDS with flowable resin composite is encouraged for more predictable bonding.

No abstract

The purpose of this study was to evaluate the sorption and solubility of a composite resin (TPH3; Dentsply) cured with halogen light due to different storage media and curing modes. The methodology was based on the ISO 4049 standard. Two independent groups were established according to the storage time (7 days-G1; 60 days-G2). A stainless steel mould (2 mm x 8 mm ø) was used. The selected curing modes were: I (Conventional - C): 40s - 600 mW/cm2; II (Pulse I - PD): 3 s - 200 mW/cm2 + 2 min (delay) + 39 s - 600 mW/cm2; III (Pulse II): 10 s - 200 mW/cm2 + 2 min (delay) + 37 s - 600 mW/cm2; IV (Pulse III): 3 s- 600 mW/cm2 + 2 min (delay) + 37 s -600 mW/cm2. The media used were: distilled water, 75% ethanol and 100% chlorophorm. Five repetitions were made for each group. The specimens were placed in a desiccator at 37°C for 24 h and, after that, at 23°C for 1 h to be weighed until a constant mass (m1) was obtained. The discs were immersed separately into the 3 media for 7 days (G1) and 60 days (G2), and thereafter reweighed (m2). The reconditioning in the desiccator was done until a constant mass (m3) was obtained. Sorption and solubility were calculated and the data of G1 and the sorption data of G2 were subjected to two-way ANOVA and Tukey's tests (p=0.05). The solubility data of G2 were analyzed by Kruskal-Wallis test (p=0.05). For G1 and G2, no statistically significant differences were found in sorption among curing techniques (p>0.05). The solubility values were negative, which means that there was mass gain. Regarding the storage media, in G2 chlorophorm had the highest sorption values. It may be concluded that the curing modes (C and PD I, II and III) did not affect the sorption of the tested composite resin. However, different storage media influenced sorption behavior. The solubility test demonstrated negative data, masking the real solubility.

Try-in pastes correspond with their respective resin cements for most colors investigated. The color of the resin cement may influence the final color of laminate veneers. Thickness of the ceramic was the most relevant variable for color change.