Effect of Phytic Acid Etching and Airborne-Particle Abrasion Treatment on the Resin Bond Strength.

Objective: This study aimed to evaluate the bond strength of a universal adhesive to dentin (µTBS) using different time periods of airborne particle abrasion (APA) and two types of acid etching. Methods: Seventy-two human third molars were divided into 9 groups (n=8) according to dentin pretreatment: APA duration (0, 5, or 10s) and acid etching (no acid - NA, 37% phosphoric acid - PhoA, or 1% phytic acid - PhyA). APA was performed at a 0.5 cm distance and air pressure of 60 psi using 50 µm aluminum oxide particles. Afterwards, two coats of Single Bond Universal adhesive (3M) were applied to the dentin surface. Composite blocks were built using the incremental technique, sectioned into 1×1 mm slices and subjected to microtensile bond strength (µTBS) testing. Fracture patterns and surface topography of each dentinal pretreatment were evaluated using a Scanning electron microscope (SEM). Bond strength data were analyzed using two-way ANOVA and Bonferroni post-hoc tests. Results: The group that received pretreatment with 5s APA and PhoA presented higher µTBS values among all groups, which was statistically different when compared with the PhoA, 10APA+PhoA, and 5APA+PhyA groups. PhyA did not significantly influence the bond strength of the air-abraded groups. Finally, adhesive failure was considered the predominant failure in all groups. Conclusion: Dentin pretreated by airborne particle abrasion using aluminum oxide demonstrated an increase in bond strength when abraded for 5 seconds and conditioned with phosphoric acid in a universal adhesive system.

Influence of universal adhesives and silane coupling primer on bonding performance to CAD-CAM resin-based composites: A laboratory investigation.

OBJECTIVE: Obtaining strong resin bonds to computer-aided design and computer-aided manufacturing (CAD-CAM) resin-based composites with dispersed fillers (CCRBCs) poses a challenge. Therefore, this study aimed to assess the effect of three universal adhesives and a two-component silane coupling agent on the shear bond strength to three (CCRBCs). MATERIALS AND METHODS: Eight hundred and sixty-four specimens of Brilliant Crios, Lava Ultimate, and Tetric CAD were polished or grit blasted, bonded with Adhese Universal DC, One Coat 7 Universal (OC7), and Scotchbond Universal Plus Adhesive (SBU) with or without a silane primer. Shear bond strength was measured after 24 h and 10,000 thermocycles. Linear regressions were performed (α = 0.05). RESULTS: After thermocycling, bond strengths were similar for the universal adhesives on polished Brilliant Crios and Lava Ultimate (p ≥ 0.408). Grit blasted Tetric CAD showed no significant differences (p ≥ 0.096). The silane primer had minimal impact on grit blasted Tetric CAD (p ≥ 0.384). The silane primer increased the bond strength of OC7 to Brilliant Crios (p = 0.001) but decreased the adhesion of SBU to Brilliant Crios and Lava Ultimate (p ≤ 0.018). CONCLUSIONS: Bond strength of universal adhesives varied with CCRBC type. The two-component silane coupling agent showed mixed effects on adhesive performance. CLINICAL SIGNIFICANCE: Selecting universal adhesives from the same CCRBC product line does not always guarantee superior bond strength. The efficacy of silane coupling agents differs based on the bonding substrate.

Cerebral Air Embolism After Air-Powder Abrasive Dental Treatment: A Case Report.

Cerebral air embolism (CAE) occurs in various clinical situations such as surgery, angiography, and hemodialysis; most are iatrogenic. Here we report the case of a 57-year-old man who developed CAE immediately after air-powder abrasive treatment, which is commonly used in dentistry. The patient underwent air-powder abrasive treatment for peri-implantitis, and immediately after the treatment, cardiac arrest occurred and cardio- pulmonary resuscitation was performed. After resuscitation, brain computed tomography performed in the emergency room showed scattered dark density presumed to be air. The day after admission, the patient showed right hemiplegia and a multifocal cerebral infarction was observed on brain magnetic resonance imaging. Therefore, CAE was strongly suspected. After hyperbaric oxygen treatment (HBOT), which started 4 days after the incident, the patient regained consciousness and showed improvement in cognitive impairment, and only grade 4 muscle weakness was observed in the right lower extremity on the manual muscle test. This case highlights the importance of considering CAE as a possible cause of neurological symptoms occurring during clinical procedures involving air, and adds to the accumulation of evidence of therapeutic effects of delayed HBOT.

Evaluation of repair bond strength of a dental CAD/CAM resin composite after surface treatment with two Er,Cr:YSGG laser protocols following artificial aging.

The aim of the present study was to evaluate the impact of two Er,Cr:YSGG laser surface treatments on the repair bond strength of a dental CAD/CAM resin composite (Brilliant Crios) after artificial aging. Twenty-four resin-based CAD/CAM blocks were cut and 48 rectangular slabs (3 x 12 x 14 mm) were prepared. Preliminary SEM observations indicated the most favorable laser settings regarding surface modification of the tested restorative material. The CAD/CAM specimens were then divided into 4 groups (n=12) based on their surface pretreatment: no treatment, air abraded with 50-µm Al2O3 particles, and laser irradiated with two different protocols using Er,Cr:YSGG laser with average power 3.5 and 4.5 W, pulse repetition rate 35 and 50 Hz, and pulse energy 100 and 90 mJ, respectively. After surface treatments each group followed a bonding protocol with silane and a flowable resin composite was used to prepare 48 microrods. Half of the microrods of each group were subjected on shear bond strength (SBS) test (chisel-shaped blade, load cell of 500 N, crosshead speed of 1 mm/min) after 24 h, while the other half underwent artificial aging (15,000 cycles, 5-55 °C) and then SBS test. The debonded specimens were examined under an optical microscope to determine the failure mode. All specimens were also evaluated using SEM to assess the surface topography after the treatments. The results showed that SBS significantly decreased after thermocycling in all the experimental groups (p<0.05). Control group presented much lower SBS values than the other groups after both 24 h and thermocycling (p<0.05). The highest values of SBS exhibited air-abrasion group (p<0.05), followed by the two laser groups, which did not differ to each other (p>0.05). The results of the current study indicated that Er,Cr:YSGG laser irradiation can be an alternative treatment for repairing the tested resin-based CAD/CAM restorative material.

Comparison of shear bond strength of rebonded stainless steel brackets with three different enamel surface conditioning methods.

Background: During the orthodontic bonding process, the need for repositioning or rebonding of orthodontic brackets on the enamel surface occurs frequently. The aim of this study is to compare the shear bond strength (SBS) in rebonding orthodontic stainless steel brackets with three different methods of enamel surface conditioning methods. Materials and Methods: In this in vitro study, 80 human premolars that were extracted for orthodontic purposes were randomly divided into four groups and underwent orthodontic bonding procedure (N = 20). Except for the control group, three other groups underwent debonding and rebonding process in which after removing the remaining adhesive with tungsten-carbide bur, enamel surface conditioned by three different methods including re-etching with phosphoric acid, sandblasting + acid etching, and Erbium-doped Yttrium-Aluminum-Garnet laser. Then, the SBS of the bracket to the enamel surface was compared between different groups. Scanning Electron microscopy images were also obtained from a number of samples. Statistical analysis was performed by Kruskal-Wallis and Mann-Whitney tests. Results: The highest SBS was observed in the primary bond (control group) with an average of 29,440 MPa. There was a significant difference between the studied groups (P < 0.001) and only the group that was re-etched with phosphoric acid had no significant difference with the control group (P = 0.708) ∝ =0.05. Conclusion: Rebonding of brackets using phosphoric acid for reconditioning of the enamel surface creates bond strength comparable to the primary bond. Other groups had significantly lower SBS than the control group.

Surface roughness and characteristics of CAD/CAM zirconia and glass ceramics after combined treatment procedures.

BACKGROUND: The roughening of the inner surface of a fixed ceramic restoration is an important factor for the bonding process. The aim of this study is to investigate the effect of combined surface treatments (acid etching, air-abrasion and Er: YAG Laser) on surface roughness of CAD/CAM fabricated zirconia (ZrO2) and lithium-disilicate glass ceramics (LDS). METHODS: Sixty ZrO2 (Ceramill Zi) and LDS (IPS e.max CAD) specimens, (5 mm in width, 5 mm in length and 1.5 mm in height) were fabricated using CAD/CAM and sintered according to the manufacturer's instructions. All specimens subjected to three surface treatment combinations; etching with 4% hydrofluoric acide (HF), airborne-particle abrasion with 110-µm alumina (Al2O3) (AP) and Er:YAG laser (Er:YAG) (Group A-HF + AP; Group B-Er:YAG + AP, and Group C-Er:YAG + HF). Perthometer was used to measure the surface roughness of the specimens before and after the tretments. RESULTS: Group A presented the highest Ra (LDS 0.81 ± 0.27 and ZrO2 0.67 ± 0.21 after treatment) and Group C the lowest (LDS 0.45 ± 0.13 and ZrO2 0.26 ± 0.07, after treatment). Compared with before treatment, the Ra were significantly different only in Group A both ZrO2 and LDS after treatment (p < 0.05). Qualitative SEM images suggested the surface topography of the ZrO2 was smoother than the LDS. Less surface changes were observed in the Er:YAG combined procedures than HF + AP. CONCLUSIONS: HF + AP was significantly succesful in modifying the ceramic surface. Er:YAG did not sufficiently promote the surface topography, even if combined with any other treatments. Overall, surface tretments on ZrO2 not easier than LDS.

Influence of alumina air-abrasion for highly translucent partially stabilized zirconia on flexural strength, surface properties, and bond strength of resin cement

Abstract Objective This study aims to evaluate the influence of different air-abrasion pressures and subsequent heat treatment on the flexural strength, surface roughness, and crystallographic phases of highly translucent partially stabilized zirconia (Y-PSZ), and on the tensile bond strength of resin cement to Y-PSZ. Methodology Fully sintered zirconia specimens were ground with SiC paper (control) and/or air-abraded with 50 µm particles of alumina at 0.1, 0.15, 0.2, or 0.3 MPa or left as-sintered. After air-abrasion at 0.2 MPa (0.2AB), additional specimens were then heated to 1500°C, and held for one hour at this temperature (0.2AB+HT1h). Flexural strength and surface roughness were evaluated. Crystalline phase identification was also carried out using X-ray diffraction. Bonded zirconia specimens with self-adhesive resin cement were stored in distilled water at 37°C for 24 h, either with or without aging (thermal cycling 4-60°C/20000). Results were analyzed statistically by ANOVA and Tukey-Kramer tests. Results The flexural strength decreased with the increase in air-abrasion pressure, while in contrast, the surface roughness increased. The lowest flexural strength and the highest roughness value were found for the 0.2AB and 0.3AB groups, respectively. All groups contained cubic-, tetragonal ( t )-, and rhombohedral ( r )-ZrO2 phases with the exception of the as-sintered group. Upon increasing the air-abrasion pressure, the relative amount of the r -ZrO2 phase increased, with a significant amount of r -ZrO2 phase being detected for the 0.2AB and 0.3AB groups. The 0.2AB+HT1h group exhibited a similar flexural strength and t -ZrO2 phase content as the as-sintered group. However, the 0.2AB group showed a significantly higher tensile bond strength (p<0.05) than the 0.2AB+HT1h group before and after aging. Conclusion Micromechanical retention by alumina air-abrasion at 0.2 MPa, in combination with chemical bonding of a resin to highly translucent Y-PSZ using a MDP-containing resin cement may enable durable bonding.

A new approach for Y-TZP surface treatment: evaluations of roughness and bond strength to resin cemen

Abstract Objective This study aims to evaluate the effect of sonochemical treatment on the surface of yttria-stabilized tetragonal zirconia (Y-TZP) before and after the final sintering. Material and Methods Twenty-eight Y-TZP discs were divided into four groups (n=7), according to surface treatment: PRE: pre-sintering sonication with 30% nominal power for 15 min; POS: post-sintering sonication with 30% nominal power for 15 min; JAT: air abrasion with 50-μm alumina particles; and CON: control group with no treatment. The POS and JAT groups were sintered before sonication and the PRE group after sonication. Surface roughness was analyzed using confocal microscopy, after which resin cement cylinders were placed on the surface of the Y-TZP discs and subjected to mechanical microshear bond strength test until fracture. Surface roughness and microshear bond strength values underwent ANOVA and the Tukey tests. Results The surface roughness values for the PRE group (299.91 nm) and the POS group (291.23 nm) were not significantly different (p≥0.05), statistically, and the surface roughness value of the JAT group (925.21 nm) was higher than those of PRE and POS (p=0.007) groups. The mechanical microshear bond strength test showed that there was no statistically significant difference between the groups (p=0.08). Conclusions Therefore, the results showed that sonochemical treatment modifies the Y-TZP surface and is similar to the well-established sandblasting surface treatment regarding the strength of the bond with the resin cement.

Dentin pretreatment and adhesive temperature as affecting factors on bond strength of a universal adhesive system

Abstract Objectives: To evaluate the effects of dentin pretreatment and temperature on the bond strength of a universal adhesive system to dentin. Material and Methods: Ninety-six extracted non-carious human third molars were randomly divided into 12 groups (n=8) according to Scotchbond Universal Adhesive (SbU) applied in self-etch (SE) and etch-and-rinse (ER) mode, adhesive temperature (20°C or 37°C) and sodium bicarbonate or aluminum oxide air abrasion. After composite build up, bonded sticks with cross-sectional area of 1 mm2 were obtained to evaluate the microtensile bond strength (μTBS). The specimens were tested at a crosshead speed of 0.5 mm/min on a testing machine until failure. Fractured specimens were analyzed under stereomicroscope to determine the failure patterns in adhesive, cohesive (dentin or resin) and mixed fractures. The microtensile bond strength data was analyzed using two-way ANOVA and Tukey's test (α=5%). Results: Interaction between treatment and temperature was statistically significant for SbU applied in self-etch technique. Both dentin treatments showed higher bond strength for ER mode, regardless of adhesive temperature. When compared to control group, sodium bicarbonate increased bond strength of SbU in SE technique. Adhesive temperature did not significantly affect the μTBS of tested groups. Predominantly, adhesive failure was observed for all groups. Conclusions: Dentin surface treatment with sodium bicarbonate air abrasion improves bond strength of SbU, irrespective of adhesive application mode, which makes this approach an alternative to increase adhesive performance of Scotchbond Universal Adhesive to dentin.

Effect of different surface treatments on the shear bond strength of nanofilled composite repairs.

Background. Repairing aged composite resin is a challenging process. Many surface treatment options have been proposed to this end. This study evaluated the effect of different surface treatments on the shear bond strength (SBS) of nano-filled composite resin repairs. Methods. Seventy-five cylindrical specimens of a Filtek Z350XT composite resin were fabricated and stored in 37°C distilled water for 24 hours. After thermocycling, the specimens were divided into 5 groups according to the following surface treatments: no treatment (group 1); air abrasion with 50-µm aluminum oxide particles (group 2); irradiation with Er:YAG laser beams (group 3); roughening with coarse-grit diamond bur + 35% phosphoric acid (group 4); and etching with 9% hydrofluoric acid for 120 s (group 5). Another group of Filtek Z350XT composite resin samples (4×6 mm) was fabricated for the measurement of cohesive strength (group 6). A silane coupling agent and an adhesive system were applied after each surface treatment. The specimens were restored with the same composite resin and thermocycled again. A shearing force was applied to the interface in a universal testing machine. Data were analyzed using one-way ANOVA and post hoc Tukey tests (P < 0.05). Results. One-way ANOVA indicated significant differences between the groups (P < 0.05). SBS of controls was significantly lower than the other groups; differences between groups 2, 3, 4, 5 and 6 were not significant. Surface treatment with diamond bur + 35% phosphoric acid resulted in the highest bond strength. Conclusion. All the surface treatments used in this study improved the shear bond strength of nanofilled composite resin used.

Percepção dos responsáveis sobre fatores preditores do medo odontológico infantil e aceitação do uso da abrasão a ar / Caregivers'perceptions of predictors of children's dental fear and acceptance of the use of air abrasion

O objetivo deste artigo é avaliar a percepção de responsáveis sobre fatores preditores do medo odontológico e aceitação do uso de uma nova tecnologia para remoção do tecido cariado em suas crianças. Entrevista a partir de um questionário semiestruturado com 105 responsáveis por crianças, de 2 a 12 anos, atendidas na Clínica de Odontopediatria, a respeito do nível de medo/apreensão, conhecimento e importância de novos estudos e autorização para utilização de novas tecnologias. Os dados foram analisados descritivamente e utilizando o teste Exato de Fisher (p<0,05). Embora os responsáveis tenham poucas informações sobre os métodos alternativos de remoção de cárie, eles são receptivos ao uso dos mesmos em seus filhos.

The purpose this article is to evaluate the caregivers'perception of predictors of dental fear and acceptance of use a new technology for removal of caries in their children. Interview using a semi-structured questionnaire with 105 caregivers for children 2 to 12 years attending at Clinic of Pediatric Dentistry. The data were about dental fear/ apprehension; knowledge and importance of new studies and permission to use new technologies. Data were analyzed descriptive and using the Fisher’s Exact test (p <0.05). A lthough t he c aregivers have little information about alternative methods of caries removal, they are receptive to use them in their children.

Influence of air abrasion tips and operation modes on enamel-cutting characteristics.

OBJECTIVE: To assess the influence of air abrasion tips and system operation modes on enamel cutting. METHODS: Forty bovine teeth were abraded with the air abrasion system Mach 4.1 for 10 and 15 seconds, employing conventional and sonic tips of 0.45-mm inner diameter and a 90° angle, and 27.5-µm aluminum oxide at 5.51 bar air pressure in continuous and pulsed modes. The width and depth of the resulting cuts were measured in SEM. RESULTS: The multivariate analysis of variances revealed that, compared to the sonic tip, the conventional tip produced shallower cuts independent of the operation mode and the application period. CONCLUSIONS: The cutting patterns observed in this study suggest that the pulsed mode produced deeper cuts when both the conventional and sonic tips were used, and that the sonic tip cut more dental tissue than the conventional one.

Effect of Air Abrasion and Erbium-Doped Yttrium Aluminum Garnet (Er: YAG) laser preparation on Shear Bond Strength of Composite to Dentin.

INTRODUCTION: The aim of this study was to assess shear bond strength of composite to dentin after air abrasion and laser treatment. METHODS: 40 human extracted molars divided into 4 groups (n=10) received the following treatments. Group 1: carbide bur, Group 2: air abrasion with aluminum oxide 50 µm, Group 3: irradiated with Erbium-Doped Yttrium Aluminum Garnet (Er: YAG) laser (150 mJ/20Hz), Group 4: irradiated with Er:YAG laser (150 mJ/20Hz)+ air. Specimens in all groups were chemically etched with phosphoric acid 37% and treated with bonding agent (single bond 3M). Then, composite build-up was performed by tygon tube. After storage in distilled water at 37°c for one week, all specimens were subjected to a shear bond strength test with universal testing machine. Data were analyzed with ANOVA and T-Test. RESULTS: The mean and standard deviation of shear bond strength of the 4 groups were 20.8±6.76, 14.98±3.98, 11.43±4.36 and 14.95± 3.18 MPa, respectively. CONCLUSION: Air abrasion after laser treatment improved the shear bond strength.

Microleakage in conservative cavities varying the preparation method and surface treatment

OBJECTIVE: To assess microleakage in conservative class V cavities prepared with aluminum-oxide air abrasion or turbine and restored with self-etching or etch-and-rinse adhesive systems. Materials and Methods: Forty premolars were randomly assigned to 4 groups (I and II: air abrasion; III and IV: turbine) and class V cavities were prepared on the buccal surfaces. Conditioning approaches were: groups I/III - 37 percent phosphoric acid; groups II/IV - self-priming etchant (Tyrian-SPE). Cavities were restored with One Step Plus/Filtek Z250. After finishing, specimens were thermocycled, immersed in 50 percent silver nitrate, and serially sectioned. Microleakage at the occlusal and cervical interfaces was measured in mm and calculated by a software. Data were subjected to ANOVA and Tukey's test (α=0.05). RESULTS: Marginal seal provided by air abrasion was similar to high-speed handpiece, except for group I. There was SIGNIFICANT difference between enamel and dentin/cementum margins for to group I and II: air abrasion. The etch-and-rinse adhesive system promoted a better marginal seal. At enamel and dentin/cementum margins, the highest microleakage values were found in cavities treated with the self-etching adhesive system. At dentin/cementum margins, high-speed handpiece preparations associated with etch-and-rinse system provided the least dye penetration. CONCLUSION: Marginal seal of cavities prepared with aluminum-oxide air abrasion was different from that of conventionally prepared cavities, and the etch-and-rinse system promoted higher marginal seal at both enamel and dentin margins.

Bond strength of a composite resin to an adhesive luting cement

This study evaluated the influence of surface treatment on the shear bond strength of a composite resin (CR), previously submitted to the application of a temporary cement (TC), to an adhesive luting cement. Eight-four CR cylinders (5 mm diameter and 3 mm high) were fabricated and embedded in acrylic resin. The sets were divided into 6 groups (G1 to G6) (n=12). Groups 2 to 6 received a coat of TC. After 24 h, TC was removed and the CR surfaces received the following treatments: G2: ethanol; G3: rotary brush and pumice; G4: air-abrasion; G5: air-abrasion and adhesive system; G6: air-abrasion, acid etching and adhesive system. G1 (control) did not receive TC or any surface treatment. The sets were adapted to a matrix and received an increment of an adhesive luting cement. The specimens were subjected to the shear bond strength test. ANOVA and Tukeyʼs tests showed that G3 (8.53 MPa) and G4 (8.63 MPa) differed significantly (p=0.001) from G1 (13.34 MPa). The highest mean shear bond strength values were found in G5 (14.78 MPa) and G6 (15.86 MPa). Air-abrasion of CR surface associated with an adhesive system provided an effective bond of the CR to the adhesive luting cement, regardless the pre-treatment with the phosphoric acid.

A influência do tratamento de superfície sobre a resistência adesiva entre uma resina composta (RC), previamente submetida à aplicação de um cimento temporário (CT), e um cimento resinoso foi avaliada. Oitenta e quatro cilindros de RC (5 mm de diâmetro e 3 mm de altura) foram confeccionados e incluídos em resina acrílica. Os conjuntos foram divididos em 6 grupos (G1 a G6) (n=12). Os grupos de 2 a 6 receberam uma camada do CT. Após 24 h, o CT foi removido e as superfícies de RC receberam os seguintes tratamentos: G2: limpeza com etanol; G3: limpeza com escova rotatória e pedra pomes; G4: jateamento ; G5: jateamento e aplicação de adesivo; G6: jateamento, condicionamento ácido e adesivo. O G1(controle) não recebeu CT ou nenhum tratamento de superfície. Os conjuntos foram adaptados à matriz e receberam incremento de cimento resinoso. Os corpos de prova foram submetidos ao ensaio de cisalhamento. Os testes ANOVA e Tukey (p=0,001), demonstraram que os grupos G3 (8,53 MPa) e G4 (8,63 MPa) diferiram estatisticamente do grupo G1 (13,34 MPa). As maiores valores médios de resistência ao cisalhamento foram encontradas nos grupos G5 (14,78 MPa) e G6 (15,86 MPa). O jateamento da superfície da resina composta associado a um sistema adesivo, independente do pré-tratamento com o ácido fosfórico, proporcionou uma efetiva união ao cimento resinoso.

Métodos de reparo em resina composta: uma revisão / Methods of repair in composed resin: a revision

Apesar de a resina composta ser amplamente conhecida e utilizada com sucesso na confecção das restaurações, em alguns casos há necessidade de reparos, os quais exigem menos desgastes dentário em comparação à substituição total das restaurações. Dessa forma, o presente trabalho tem como objetivo revisar os principais procedimentos e materiais utilizados na confecção dos reparos de resina composta, assim como os testes que avaliam a força de adesão de tais procedimentos. Meios químicos e mecânicos, isolados ou associados, tem sido propostos para analisar a força de adesão ao reparo, como a utilização do ácido fluorídrico, ácido fosfórico, jateamento de óxido de alumínio, pontas diamantadas, adesivos e silano. Com base na literatura revisada, observou-se a importância do tratamento da superfície da resina a ser reparada e concluiu-se que o jateamento com óxido de alumínio, seguido da aplicação do ácido fosfórico e do adesivo foi o modo mais eficaz de seconseguir sucesso nos reparos de resina composta.

Although the composites being widely known and used with success in the restorations, in some cases repairs are necessary, which demand less dental waste in comparison with the total substitution of the restorations. In that way, the aim of this work was to review the main procedures and materials used in repairs of composites, as well as the explaining of the tests that evaluated the bond strength of such procedures. A number of techniques have been proposed to improve bond strength of composite repair through roughening, etching the substrate surface with acidulated phosphate fluoride, HF acid gel, air-borne particle abrasion or using adhesive resins. Based on the reviewed bibliography, the importance of the treatment of the surface was observed from the resin to be repaired, and it was concluded that the air-borne particle abrasion was the most effective way for composites, followed by the application of the HF acid gel and adhesive resins.

Sucção de alta potência no controle das partículas emitidas pelo sistema de abrasão a ar em consultório odontológico / Control of particles emitted by air-abrasion system with high-power suction in a dental office

O estudo, de desenho transversal, teve como objetivo levantar a prevalência de sobrepeso e obesidade em trabalhadores de cozinhas (n = 200) de oito hospitais públicos localizados na grande Florianópolis, Santa Catarina, verificando se há algum fator de risco específico relacionado às condições de trabalho. Utilizaram-se, como grupo de comparação, trabalhadores das lavanderias (n =178) dos mesmos hospitais. Os dados foram coletados através de questionário estruturado e levantamento de medidas de peso e estatura. A prevalência de sobrepeso e obesidade (IMC 25 kg/m2) foi maior entre os trabalhadores de cozinhas, encontrando-se associação positiva entre as mulheres (RP = 1,3; IC 95% = 1,1 a 1,5). A variável beliscar alimentos no local de trabalho mostrou se condição específica dos trabalhadores de cozinhas independentemente do sexo, sendo que os homens e as mulheres das cozinhas beliscam alimentos freqüentemente no trabalho 5,7 e 3,9 vezes mais que os homens e mulheres das lavanderias, respectivamente. Sendo assim, o acesso ao alimento pode estar relacionado à manutenção do excesso de peso e a maiores médias de peso entre as mulheres.

The aim of this study is to check the prevalence of overweight and/or obesity in kitchen workers and to observe if there is any specific risk factor related to their working conditions. It is a cross-sectional study with all the kitchen (n =200) and laundry (n = 178) workers of eight public hospitals in Florianópolis, Santa Catarina, a state located in the South of Brazil. Collecting of data included checking their weighs and measures and their answers to a questionnaire. The prevalence of overweight and obesity (BM I? 25 kg/m2) was higher among kitchen workers; a positive association was found for females only (Prevalence Rate Ratio = 1,3; 95% CI; 1,1; 1,5). The variable food snacking in the workplace was found to be typical for kitchen workers, either male or female. It was also found that both male and female kitchen workers frequently snack 5.7 and 3.9 more in the workplace than laundry workers. The easy access to food may be the reason for the highest weight levels among women

The effect of air abrasion on dentin-resin adhesive system / 实用口腔医学杂志

Objectives:To evaluate the adhesive effect of resin and dentin perpared by air abrasion. Methods:Dentin of 48 permanent molars was exposed and treated with ① air sand blasting+whole acid corrosion+Estet. X TM,② air sand blasting+SE BOND,③ air sand blasting+Esthet. X TM,④Turbine+whole acid corrosion+Esthet.X TM respectively with 12 samples in each group. Then resin adhesive was applied.Microtensile testing was used to examine the microtensile bond strength. SEM was used to observe the change of resin jags. Results:The microtensile bonding strength in group ①,②,③ and ④ was 27.96?1.42, 29.84?2.56,14.48?2.45 and 27.73?1.48 respectively (① vs ③,② vs ③ and ③ vs ④ P