Margareth Oda

Avaliação morfológica da união entre adesivo/resina composta e dentina irradiada com laser Er:YAG e laser Nd:YAG: estudo comparativo por microscopia de varredura

Since bonding systems were introduced in the restorative procedures carried out with esthetic materials, the treatment of dentin surfaces has been widely studied in order to establish the ideal technique. The application of 37% phosphoric acid on dentin is still the best known method. However, alternative methods for treating the dentin surface have been discussed in the literature, including the utilization of some kinds of laser irradiation. The purpose of this research was to morphologically evaluate the bond between adhesive materials and the dentin treated with Er:YAG and Nd:YAG lasers, in a comparative study by means of scanning electron microscopy (SEM). Irradiation either substituted acid etching, or was associated to it. Recently extracted bovine incisors were utilized. They received class V cavity preparations and were restored with a bonding system and a light-cured composite resin. Meanwhile, some of the teeth underwent irradiation with Er:YAG laser or Nd:YAG laser before the application of the bonding agent and the composite resin. The samples were selected, prepared for SEM and submitted to morphological analysis. Data were registered in photomicrographs. Based on the microscopic observations, we concluded that only in the dentin surfaces submitted to irradiation with Er:YAG laser and to acid conditioning there was penetration of resin into the dentine. With the Nd:YAG laser treatment, there was only visual superposition of resin over the dentin surface, which suggests that there was only occlusion of the tubules, with characteristics of fusion in the superficial dentine.

Long-term bond strength of adhesive systems applied to etched and deproteinized dentin

The aim of this study was to evaluate the early and 12-month bond strength of two adhesive systems (Single Bond-SB and One Step-OS) applied to demineralized dentin (WH) and demineralized/NaOCl-treated dentin (H). Twenty flat dentin surfaces were exposed, etched, rinsed and slightly dried. For the H groups, a solution of 10% NaOCl was applied for 60 s, rinsed (15 s) and slightly dried. The adhesives were applied according to the manufacturers instructions and composite resin crowns were incrementally constructed. After 24 h (water-37°C), the specimens was sectioned in order to obtain resin-dentin sticks (0.8 mm2). The specimens were tested in microtensile (0.5 mm/min) immediately (IM) or after 12 months of water storage (12M). The data (MPa) were subjected to ANOVA and Tukeys test (α=0.05). Only the main factors adhesive and time were significant (p=0.004 and p=0.003, respectively). SB (42.3±9.1) showed higher bond strengths than OS (33.6±11.6). The mean bond strength for IM-group (42.5±8.7) was statistically superior to 12M (33.3±11.8). The use of 10% NaOCl, after acid etching, did not improve the immediate and the long-term resin-dentin bond strength.

Avaliaçäo da rugosidade superficial de três resinas compostas submetidas a diferentes técnicas de polimento

In this study, the superficial roughness of two composite resins classified as condensable and of a traditional hybrid composite resin was analyzed after different polishing techniques. Test specimens were confected, immersed in distilled water for 24 hours and submitted to two different techniques of superficial treatment, in which disc systems (Sof-LexTM and Super Snap®) and silicon tips (Enhance®) were utilized. The results revealed the greater superficial roughness of AlertTM, when compared with Solitaire® and Degufill Mineral® - no statistically significant differences were observed between the last two materials. The superficial roughness of the specimens polished with Enhance® tips was greater than that of the specimens polished with discs and there were no statistically significant differences between both disc systems.In this study, the superficial roughness of two composite resins classified as condensable and of a traditional hybrid composite resin was analyzed after different polishing techniques. Test specimens were confected, immersed in distilled water for 24 hours and submitted to two different techniques of superficial treatment, in which disc systems (Sof-Lex and Super Snap) and silicon tips (Enhance) were utilized. The results revealed the greater superficial roughness of Alert, when compared with Solitaire and Degufill Mineral--no statistically significant differences were observed between the last two materials. The superficial roughness of the specimens polished with Enhance tips was greater than that of the specimens polished with discs and there were no statistically significant differences between both disc systems.

Estudo in vitro da microinfiltração marginal em cavidades submetidas ao tratamento com laser de Er:YAG e restauradas com materiais estéticos

The aim of this in vitro study was to evaluate marginal microleakage in class V preparations submitted to treatment with Er:YAG laser and restored with aesthetic materials. Sixty human molars were selected and class V cavities were prepared on the buccal and lingual aspects of their cervical thirds. The restorative technique followed the instructions of the manufacturers. The samples were divided in 3 groups of 20 teeth each: Group 1--control; Group 2--Er:YAG laser was applied on the enamel margin before the restoration was placed; Group 3--a thin layer of calcium hydroxide was applied on the axial wall before the restoration was placed. Each group was divided in 4 sub-groups and the teeth were restored with different aesthetic materials. All samples were submitted to thermocycling and stained with 50% silver nitrate. Based on the obtained results, we could conclude that there are statistically significant differences between the 12 experimental conditions tested. The samples which presented the greatest microleakage were those treated with Er:YAG laser and restored with light-cured glass ionomer cement, followed by those that received Er:YAG laser and the sandwich technique, the cavities restored with light-cured glass ionomer cement and those restored by means of the sandwich technique, in this order.The aim of this in vitro study was to evaluate marginal microleakage in class V preparations submitted to treatment with Er:YAG laser and restored with aesthetic materials. Sixty human molars were selected and class V cavities were prepared on the buccal and lingual aspects of their cervical thirds. The restorative technique followed the instructions of the manufacturers. The samples were divided in 3 groups of 20 teeth each: Group 1 - control; Group 2 - Er:YAG laser was applied on the enamel margin before the restoration was placed; Group 3 - a thin layer of calcium hydroxide was applied on the axial wall before the restoration was placed. Each group was divided in 4 sub-groups and the teeth were restored with different aesthetic materials. All samples were submitted to thermocycling and stained with 50% silver nitrate. Based on the obtained results, we could conclude that there are statistically significant differences between the 12 experimental conditions tested. The samples which presented the greatest microleakage were those treated with Er:YAG laser and restored with light-cured glass ionomer cement, followed by those that received Er:YAG laser and the sandwich technique, the cavities restored with light-cured glass ionomer cement and those restored by means of the sandwich technique, in this order.

Er:YAG‐laser and sodium hypochlorite influence on bond to dentin

The aim of this in vitro study was to verify the interference of previous application of sodium hypochlorite in the bond strength to dentin irradiated with Er:YAG laser (80 mJ, 2 Hz, 25 J/cm2), using two adhesive systems with different solvents (Adper Single Bond2 – 3M ESPE [SB] and Prime&Bond 2.1 – Dentsply [PB].

Estudo de resistência à tração de três sistemas adesivos associados a resina composta em superfícies dentinárias

The aim of this in vitro study was to compare the tensile bond strength of 3 different bonding systems, associated to composite resins, bonded to dentinal surfaces. Forty-four dentinal surfaces were obtained from recently extracted human molars. A standardized smear layer was obtained and the surfaces were divided in 3 groups: G1) self etch + microhybrid composite; G2) single-component adhesive + phosphoric acid + microhybrid composite and G3) conventional system (acid + primer + bond) + microhybrid composite. Specimens made of composite resin were constructed in the shape of an inverted truncated cone with 3 mm of diameter. Tensile bond strength test was performed at the speed of 0.5 mm/min, and the results were expressed in MPa. The analysis of variance ANOVA (p < 0.05) determined that the type of bonding system used influenced tensile bond strength. Tukeys test, however, showed that the results of the comparison between G2 and G3 were the only statistically significant ones, with G2 showing greater values of tensile bond strength.

Tensile bond strength of different adhesive systems to primary dentin treated by Er:YAG laser and conventional high-speed drill

The aim of this study was to evaluate the tensile strength of different adhesive systems to primary tooth dentin prepared by high-speed drill and Er:YAG laser (2.94μm). Buccal surfaces of 38 primary canines were ground and flattened with sand paper disks (#120-600 grit) and distributed into five groups (n=15): G1: diamond bur in high-speed drill (HD)+ 35% phosphoric acid (PA)+Single Bond (SB); G2: HD+self-etching One Up Bond F (OUB);G3: Er:YAG laser (KaVo 3- LELO-FOUSP)(4Hz, 80mJ, 25,72J/cm2) (L)+PA+SB, G4: L+SB, G5: L+OUB. The inverted truncated cone samples built with Z-100 composite resin after storage in water (37°C/24h) were submitted to tensile bond strength test on Mini Instron 4442 (0.5mm/min, 500N). The data were analyzed with ANOVA and Tukey Test (p<0.05). The mean (MPa) were: G1-3.18(±1.24); G2-1.79(±0.73); G3-3.17(±0.44); G4-8.29(±1.86); G5-7.11(±2.07). The data analyzed with ANOVA and Tukey Test showed that Laser associated with PA+SB, SB or OUB lead to increased bonding values when compared to HD+PA+SB and HD+OUB (p=0.000), L+SB showed higher values than L+PA+SB and L+OUB (p=0.0311). Er:YAG laser radiation promoted significant increase of bond strength of different adhesive systems evaluated in the dentin of primary teeth.