Computer-aided design and computer-aided manufacturer indirect versus direct composite restorations: A randomized clinical trial.

OBJECTIVE: This study compared the clinical performance of large indirect restorations (IRs) versus direct restorations (DRs) in posterior teeth. METHODS: Thirty subjects received two class II restorations (n = 60), one fabricated from a precured composite block (Grandio Blocs, VOCO) for the indirect technique (IT) and the other with light-cured composite (GrandioSO, VOCO) for the direct technique (DT). For IT, the restoration was created using the computer-aided design and computer-aided manufacturer (CAD/CAM) system. For DT, the material was applied light-cured by using a layering technique. All restorations were evaluated by using the World Dental Federation criteria. RESULTS: Twenty-three subjects attended the 2-year recall, and 46 restorations were evaluated. No significant differences were detected between the techniques for most parameters analyzed (p > 0.05). For "color match" at 7 days and 6 months, better results were observed for the DT. In relation to the overall scores, all restorations were esthetically acceptable after 2 years, while 93.3% of DT and 90% of IT showed acceptable function. For biological scores, 96.67% of DRs and 100% of IRs was acceptable after 24 months. Considering all properties, the success rates were 93.3% for DRs and 90% for IRs. CONCLUSIONS: After 2 years, both restorations presented similar and good clinical behavior for all the properties analyzed. CLINICAL SIGNIFICANCE: Light-cured direct posterior composite restorations may perform similarly to indirect composite restorations made with precured CAD/CAM composite blocks up to 2 years.

Artificial Saliva Formulations versus Human Saliva Pretreatment in Dental Erosion Experiments.

The aim of this study was to evaluate the erosion-preventive effect of different artificial saliva formulations and human saliva in vitro compared to human saliva in situ. In the in vitro experiment, bovine enamel and dentin specimens were stored in artificial saliva (4 different formulations, each n = 20), deionized water (n = 20) or human saliva (n = 6 enamel and dentin specimens/volunteer) for 120 min. In the in situ experiment, each of the 6 enamel and dentin specimens was worn intraorally by 10 volunteers for 120 min. The specimens were then eroded (HCl, pH 2.6, 60 s). Half of the specimens were subjected to microhardness analysis (enamel) and the determination of calcium release into the acid (enamel and dentin), while the other half were again placed in the respective medium or worn intraorally, respectively, for 120 min before a second erosion was performed. Knoop microhardness of enamel and the calcium release of enamel and dentin into the acid were again determined. Statistical analysis was conducted by two-way repeated-measures ANOVA or two-way ANOVA (α = 0.05). Enamel microhardness was not significantly different between all test groups after the first and the second erosive challenge, respectively. Enamel calcium loss was significantly lower in situ compared to the in vitro experiment, where there was no significant difference between all test groups. Dentin calcium loss was significantly lower than deionized water only after the first and than all except one artificial saliva after the second erosion. Under the conditions of this experiment, the use of artificial saliva formulations and human saliva in vitro does not reflect the intraoral situation in dental erosion experiments adequately.

Adhesive Systems as an Alternative Material for Color Masking of White Spot Lesions: Do They Work?

PURPOSE: To evaluate the color masking effect of infiltration treatment of artificial white spot lesions (AWSL) using a dedicated resin in comparison to different adhesive systems. MATERIALS AND METHODS: Enamel/dentin specimens were obtained from bovine incisors and baseline color was assessed using a reflectance spectrophotometer, according to the CIE L*a*b* system. AWSL were produced using a buffered acid solution and a new color evaluation was performed. The specimens were divided into 8 groups: control: artificial saliva changed daily for 7 days; IC: infiltrating resin Icon; EC: EquiaCoat; FU: Futurabond U; SBU: Single Bond U; SBMP: Scotchbond MP; OB: OptibondFL; BF: Bioforty. After the treatments, the color was evaluated again and the values for the parameters ΔL (change in lightness), Δa (change in chroma), Δb (change in hue), and ΔE (general color difference) were calculated in relation to baseline. Data were analyzed by one-way ANOVA and Tukey's tests. RESULTS: After treatment, ANOVA showed significant differences for all parameters (p = 0.001). Tukey's test showed the greatest lightness reduction (ΔL) for the IC group, followed by EC, FU, and SBU. The SBMP, OB, and BF groups were similar to the control. For Δb values, all groups showed differences in relation to the control, with no differences between them. In relation to ΔE, all groups showed differences in relation to the control (ΔE = 5.24), with no significant differences between them. ΔE values after application of all resinous materials were lower than the threshold of 3.7, indicating effective color masking. CONCLUSIONS: The Icon infiltrant produced a greater lightness reduction of white lesions (ΔL). For general color difference (ΔE), all the resinous materials tested were able to color mask artificial AWSL.

Analysis of the Color and Fluorescence Alterations of Enamel and Dentin Treated With Hydrogen Peroxide.

The aim of this study was to evaluate the effect of hydrogen peroxide whitening on fluorescence and color of bovine enamel and dentin. Twenty five dentin discs and 25 enamel discs, with 6 mm diameter and 1 mm thick, were obtained. Direct fluorescence (spectrofluorophotometry) and color (spectrophotometry) were assessed. After fluorescence and color baseline measurements, specimens were immersed in a 35% hydrogen peroxide (HP) solution for 1 h. This procedure was repeated after 7 days. Final fluorescence and color measurements were performed after the second immersion. Chemical characterization of 5 additional specimens was also performed. Data were submitted to repeated analysis of variance and Tukey's test for fluorescence and unpaired t-test for color and chemical components (p<0.05). Fluorescence decreased significantly in dentin specimens after whitening. Enamel presented lower fluorescence than dentin at baseline, but this parameter did not decrease after whitening. Color changes were observed for both substrates, with significantly greater whitening effect in dentin (ΔE=10.37) (p<0.001). Whitening by hydrogen peroxide induced significant decrease in fluorescence of tooth dentin and promoted significant color changes in dentin and enamel with more accentuated outcomes in dentin.

Effects of Different Surface Treatments on Composite Repairs.

PURPOSE: To evaluate the influence of different surface treatments on roughness and bond strength of composite repairs. MATERIALS AND METHODS: 120 truncated conical specimens were prepared with composite Grandio SO (VOCO) and submitted to 5000 thermal cycles. Specimens were divided into 12 groups (n = 10) regarding the surface treatments: negative control (NC), without treatment; medium-grit diamond bur (MGD); coarse-grit diamond bur (CGD); conventional carbide bur (ConC); crosscut carbide bur (CutC); chemical vapor deposition diamond bur (CVD); sandblasting with aluminum oxide (AlO); Er:YAG laser 200 mJ/10 Hz (Er200); Er:YAG laser 60 mJ/10 Hz (Er50); Nd:YAG laser 120 mJ/15 Hz (Nd120); Nd:YAG laser 60 mJ/ 15Hz (Nd60); air abrasion with 110-µm silica modified aluminum oxide (Rocatec Plus-3M) (SIL). After the surface treatments, the surface roughness (Ra) was measured using a profilometer, and then the adhesive system Admira Bond (VOCO) was applied. Another truncated conical restoration was built up with the same composite over the bonded area of each specimen. In order to evaluate the cohesive strength, double-cone specimens were made and considered as a control group (CoheC). The specimens were submitted to tensile bond strength testing and the obtained data (MPa) were evaluated by one-way ANOVA, Tukey's and correlation tests. RESULTS: ANOVA showed significant differences among experimental groups for roughness and adhesive strength (p < 0.00). The roughness values (Ra) were: NC (0.21 ± 0.19)(c); ConC (0.30 ± 0.08)(c); CutC (0.50 ± 0.22)(cd); CVD (0.74 ± 0.14)(bd); MGD (0.89 ± 0.39)(ab); Er50 (0.89 ± 0.14)(ab); AlO (0.90 ± 0.07)(ab); Nd60 (0.94 ± 0.33ab; SIL (0.98 ± 0.07)(ab); Nd120 (1.10 ± 0.19)(a); CGD (1.10 ± 0.32)(a); Er200 (1.12 ± 0.21)(a). The results of the tensile bond strength test in MPa were: CGD (11.58 ± 3.03)(a); MGD (12.66 ± 3.82)(ab); NC (13.51 ± 3.95(ab); Nd120 (14.11 ± 5.95)(ab); ConC (14.73 ± 6.12)(ab); Er200 (15.51 ± 1.45)(abc); CVD (15.61 ± 5.00(abc); Er50 (16.44 ± 2.75) (abc); CutC (16.79 ± 2.98)(abc); Nd60 (17.72 ± 2.45)(abcd); AlO (18.33 ± 3.19)(bcd); SIL (21.13 ± 4.48(cd); CoheC (23.50 ± 5.81)(d). The groups followed by the same letters were not statistically significantly different (Tukey's test). No correlation was found between bond strength and roughness (r = 0.007). CONCLUSION: Air abrasion with silica coating (Rocatec) was the only method which resulted in significantly higher bond strength in relation to the negative control group. The increase in laser energy produced a rougher surface, but reduced the bond strength.

Changes in irradiance and energy density in relation to different curing distances.

The present study aimed to assess the influence of curing distance on the loss of irradiance and power density of four curing light devices. The behavior in terms of power density of four different dental curing devices was analyzed (Valo, Elipar 2, Radii-Cal, and Optilux-401) using three different distances of photopolymerization (0 mm, 4 mm, and 8 mm). All devices had their power density measured using a MARC simulator. Ten measurements were made per device at each distance. The total amount of energy delivered and the required curing time to achieve 16 J/cm(2) of energy was also calculated. Data were statistically analyzed with one-way analysis of variance and Tukey's tests (p < 0.05). The curing distance significantly interfered with the loss of power density for all curing light devices, with the farthest distance generating the lowest power density and consequently the longer time to achieve an energy density of 16 J/cm(2) (p < 0.01). Comparison of devices showed that Valo, in extra power mode, showed the best results at all distances, followed by Valo in high power mode, Valo in standard mode, Elipar 2, Radii-Cal, and Optilux-401 halogen lamp (p < 0.01). These findings indicate that all curing lights induced a significant loss of irradiance and total energy when the light was emitted farther from the probe. The Valo device in extra power mode showed the highest power density and the shortest time to achieve an energy density of 16 J/cm(2) at all curing distances.

Influence of whitening gel application protocol on dental color change.

OBJECTIVES: To evaluate the influence of different whitening protocols on the efficacy of 35% hydrogen peroxide (HP) tooth whitening and gel pH and concentration. MATERIAL AND METHODS: Eighty-four enamel/dentin discs from bovine incisors were used. The baseline color was measured with a spectrophotometer. Two sessions of in-office whitening with 35% HP were performed under different protocols: G1: 3 applications of HP (10 min each) per session; G2: 1 application of 30 min per session; G3: 1 application of 40 min per session, with no gel replenishment within session for groups 2 and 3. HP titration and pH evaluation at baseline, after 10, 30, and 40 min were also performed. The final color was measured 24 h after the 1st and 2nd whitening sessions. Data were submitted to Repeated Measures ANOVA and Tukey's test. RESULTS: For color evaluation, no differences were observed among groups after two sessions. HP titration showed no drop on concentration after 10, 30, or 40 min. The pH was 5.54 at baseline and 5.41 after 40 min. CONCLUSION: Replenishment or extended application time of in-office whitening gel does not affect gel pH and concentration, a fact that supports the similar effectiveness of whitening observed among the tested protocols.

Influence of Different Types and Concentrations of Chemical Catalysts on Dental Bleaching Efficiency.

The objective of this study was to evaluate the effects of different types and concentrations of chemical catalysts on the efficiency of 35% hydrogen peroxide gel on dental bleaching. Enamel-dentin disks were obtained from bovine incisors and the initial color was assessed. The groups were divided according to the type and concentration of catalyst added to an experimental gel: ferrous sulphate (FS) (0.001, 0.002 and 0.003%); ferrous gluconate (Fg) (0.01, 0.02 and 0.03%); ferric chloride (FC) (0.01, 0.02 and 0.03%); manganese gluconate (MG) (0.01, 0.02 and 0.03%); and manganese chloride (MC) (0.01, 0.02 and 0.03%). The positive control (PC) group received the bleaching gel without any catalyst, while in the negative control (NC) the specimens remained in artificial saliva. Three applications of the bleaching gels were performed for 10 minutes each, repeated after 7 days. Color assessments were performed 7 days after the first session and 7 days after the second. The specimens were stored in artificial saliva and assessed again after 1 year. The data were analyzed by parametric analysis of variance and Tukey's test. Some of the chemical catalysts tested were effective in reducing the yellowish color of the samples in relation to the positive control group after 1 and 2 applications and diminished the color relapse over time. After 1 year, the FS was the most effective catalyst tested. We concluded that some chemical catalysts increased the efficiency of dental bleaching.

Effect of Nd:YAG laser on the solvent evaporation of adhesive systems.

OBJECTIVE: This study evaluated the influence of Nd:YAG laser on the evaporation degree (ED) of the solvent components in total-etch and self-etch adhesives. MATERIALS AND METHODS: The ED of Gluma Comfort Bond (Heraeus-Kulzer) one-step self-etch adhesive, and Adper Single Bond 2 (3M ESPE), and XP Bond (Dentsply) total-etch adhesives was determined by weight alterations using two techniques: Control--spontaneous evaporation of the solvent for 5 min; Experimental--Nd:YAG laser irradiation for 1 min, followed by spontaneous evaporation for 4 min. The weight loss due to evaporation of the volatile components was measured at baseline and after 10 s, 20 s, 30 s, 40 s, 50 s, 60 s, 70 s, 80 s, 90 s, 100 s, 110 s, 2 min, 3 min, 4 min, and 5 min. RESULTS: Evaporation of solvent components significantly increased with Nd:YAG laser irradiation for all adhesives investigated. Gluma Comfort Bond showed significantly higher evaporation of solvent components than Adper Single Bond 2 and XP Bond. All the adhesives lost weight quickly during the first min of Nd:YAG laser irradiation. CONCLUSION: The application of Nd:YAG laser on adhesives before light curing had a significant effect on the evaporation of the solvent components, and the ED of Gluma Comfort Bond one-step self-etch adhesive was significantly higher than with Adper Single Bond 2 and XP Bond total-etch adhesives. CLINICAL RELEVANCE: The use of the Nd:YAG laser on the uncured adhesive technique can promote a greater ED of solvents, optimizing the longevity of the adhesive restorations.

Effect of incorporation of remineralizing agents into bleaching gels on the microhardness of bovine enamel in situ.

AIM: This study evaluated the effect of adding calcium or fluoride to 35% hydrogen peroxide (HP) bleaching gel and the effect of human saliva on the microhardness of sound and demineralized enamel, using an in situ model. MATERIALS AND METHODS: Cylindrical bovine enamel specimens (3 × 2 mm) were divided into two groups (n = 30): sound enamel (SE) and demineralized enamel (DE). Each group was divided into three subgroups, according to the bleaching gel: 35% HP; 35% HP + calcium; 35% HP + fluoride. After bleaching therapy, the specimens were fixed to intraoral devices worn by 10 volunteers for 7 days. Surface enamel microhardness (SMH) was measured before and after bleaching procedures, and after 1 and 7 days of saliva exposure. Data were analyzed by Repeated Measures ANOVA (5%). RESULTS: The variable time resulted in significant differences for SE and DE groups (p = 0.001). For SE, significantly lower SMH was detected for control at post-bleaching period in comparison to the baseline and after 7 days. For DE, the lowest mean values were obtained before bleaching, and the addition of calcium to the peroxide significantly increased enamel SMH. The exposure to human saliva resulted in increased SMH. CONCLUSION: The addition of potential remineralizing agents into bleaching gels might play an important role in maintaining the microhardness of sound enamel and in inducing remineralization of artificially demineralized enamel right after bleaching, and the remineralizing action of human saliva might minimize the deleterious effects of bleaching gels on enamel. Clinical significance: The incorporation of calcium into HP bleaching gel might be beneficial for the initial phases of the bleaching procedure.

A split-mouth randomized clinical trial of conventional and heavy flowable composites in class II restorations.

OBJECTIVE: The aim of this study was to evaluate the 2-year clinical performance of class II restorations made with a composite resin with two different viscosities. METHODS: 47 patients received two class II restorations (n=94), one made with GrandioSO (conventional viscosity - CV), and the other with GrandioSO Heavy Flow (flowable viscosity - FV), subjecting both materials to the same clinical conditions. The self-etching adhesive Futurabond M was used for all restorations. The composites were inserted using the incremental technique. The restorations were evaluated using the modified USPHS criteria according to the periods: baseline, 6 months, 1 year and 2 years after restorative procedures. RESULTS: After 24 months, 40 patients attended the recall and 78 restorations were evaluated. In all periods, no secondary caries was observed. After 6 months, there were slightly overall changes of scores for most parameters. After 24 months, the higher number of changes from score Alfa to Bravo was observed for marginal discolouration (32.5% - CV and 39.5% - FV) and colour match (15% - CV and 31.6% - FV), followed by proximal contact (25% - CV and 23.7% - FV) and marginal adaptation (20% - CV and 21.1% - FV). For wear, surface texture and postoperative sensitivity the changes were very small. Just two restorations were lost during the 24-month follow up. Less than 5% of all restorations showed postoperative sensitivity. Chi-square test showed no significant differences between the two materials for all parameters analysed. CONCLUSION: After 2 years of clinical service, no significant differences were observed between GrandioSO conventional and GrandioSO Heavy Flow for the parameters analysed. Both materials provided acceptable clinical behaviour in class II restorations. CLINICAL SIGNIFICANCE: This study presents the possibility of using a flowable composite with high filler content, for performing class II restorations.

Five-year clinical performance of the dentine deproteinization technique in non-carious cervical lesions.

OBJECTIVE: The aim of this study was to evaluate the 5-year clinical performance of composite restorations of non-carious cervical lesions (NCCL) using a total-etch adhesive system with or without collagen removal with 10% sodium hypochlorite (NaOCl). METHODS: In this study randomized controlled split-mouth clinical trial, one-hundred and thirty-eight NCCL were restored into 30 patients. Each patient received at least one pair of composite restorations (Filtek A110/3M ESPE), bonded either with 2 techniques: Conventional Technique--acid etching with 37% phosphoric acid+Prime & Bond NT (Denstply DeTrey); Deproteinization Technique--acid etching with 37% phosphoric acid+10% NaOCl for 1min+Prime & Bond NT. The two techniques were evaluated using the United States Public Health Service (USPHS) criteria at baseline, 18 months, 3 and 5 years. After five years, one-hundred and six restorations were evaluated in 24 patients. Data were analyzed using the Chi-Square test (p<0.05). RESULTS: There were no statistically significant differences between the two techniques regarding the evaluated parameters (p>0.05). CONCLUSION: After 5 years, the application of 10% NaOCl deproteinization on etched dentine did not affect the clinical performance of composite restorations placed in NCCL when compared to the conventional total-etch technique. CLINICAL SIGNIFICANCE: Clinical studies evaluating the performance of the Deproteinization Technique are scarce. In this study, this technique showed similar clinical performance at the end of 5 years when compared to a conventional total-etch technique.

Effect of remineralizing agents on the bleaching efficacy of gels.

Adding remineralizing agents to bleaching gels has been proposed to reduce the mineral loss of enamel and tooth sensitivity. This study sought to investigate the efficacy of hydrogen peroxide (HP) gel after the addition of calcium and fluoride. Ninety enamel-dentin discs were prepared from bovine incisors. The specimens were divided into 3 groups: a negative control group (nonbleached) and 2 experimental groups, 1 bleached with 7.5% HP (at-home bleaching) and the other with 35% HP (in-office bleaching). Each group was subdivided into 3 subgroups, according to the addition of remineralizing agents on gels: no remineralizing agents, addition of 2% calcium gluconate, and addition of 2% sodium fluoride. For 14 days, the gels were applied 1 hour/day for at-home bleaching and 50 minutes/week for in-office bleaching. Between bleaching, the specimens were immersed in artificial saliva. The results showed significant differences in all bleached groups compared to the nonbleached negative control group. No significant differences were observed for any parameters tested when the different treatments were compared using 2-way ANOVA. It was concluded that adding remineralizing agents to the gels did not interfere with their whitening effect and that both concentrations tested offered similar bleaching outcomes.

Bond strength of adhesive systems with different solvents to dry and wet dentin.

AIM: This study evaluates bond strength between dentin and composite using adhesives with different solvents to dry and wet dentin. MATERIALS AND METHODS: Ninety bovine incisors were used; the vestibular surfaces were worn by the exposure of an area with a diameter of 4 mm of dentin. The specimens were divided into 6 groups, according to the type of adhesive used and hydratation stals: Group SB-wet: Single Bond 2 in wet dentin, Group SBdry: Single Bond 2 in dry dentin, Group SL-wet: Solobond M in wet dentin, Group SL-dry: Solobond M in dentin dry. Group XPwet: XP Bond in wet dentin, Group XP-dry: XP Bond in dentin dry. They were cut to obtain specimens in the shape of stick with 1 × 1 mm and subjected to microtensile test in universal testing machine with a cross speed of 1mm/min. The data were analyzed with ANOVA and Tukey's tests (5%). RESULTS: ANOVA showed significant differences for surface treatment and interaction, but no difference was found for adhesive factor. The Tukey's test showed that the samples with wet dentin shown higher values of bond strength. CONCLUSION: The adhesive did not influence in the bond strength. The groups with wet dentin showed higher values of bond strength than groups with dry dentin.

Influence of CVD diamond tips and Er:YAG laser irradiation on bonding of different adhesive systems to dentin.

AIM: The aim of this study was to compare the microtensile bond strength of three adhesive systems, using different methods of dentin preparation. MATERIALS AND METHODS: A hundred and eight bovine teeth were used. The dentin from buccal face was exposed and prepared with three different methods, divided in 3 groups: Group 1 (DT)- diamond tip on a high-speed handpiece; Group 2 (CVD)-CVD tip on a ultrasonic handpiece; Group 3 (LA)-Er: YAG laser. The teeth were divided into 3 subgroups, according adhesive systems used: Subgroup 1-Adper Single Bond Plus/3M ESPE (SB) total-etch adhesive; Subgroup 2-Adper Scotchbond SE/3M ESPE (AS) selfetching adhesive; Subgroup 3-Clearfil SE Bond/Kuraray (CS) selfetching adhesive. Blocks of composite (Filtek Z250-3M ESPE) 4 mm high were built up and specimens were stored in deionized water for 24 hours at 37°C. Serial mesiodistal and buccolingual cuts were made and stick-like specimens were obtained, with transversal section of 1.0 mm(2). The samples were submitted to microtensile test at 1 mm/min and load of 10 kg in a universal testing machine. Data (MPa) were subjected to ANOVA and Tukey's tests (p < 0.05). RESULTS AND CONCLUSION: Surface treatment with Diamond or CVD tips associated with Clearfil SE Bond adhesive produced significantly lower bond strength values compared to other groups. Surface treatment with Er: YAG laser associated with Single Bond Plus or Clearfil SE Bond adhesives and surface treatment with CVD tip associated with Adper Scotchbond SE adhesive produced significantly lower bond strength values compared to surface treatment with diamond or CVD tips associated with Single Bond Plus or Adper Scotchbond SE adhesives. CLINICAL SIGNIFICANCE: Interactions between laser and the CVD tip technologies and the different adhesive systems can produce a satisfactory bonding strength result, so that these associations may be beneficial and enhance the clinical outcomes.

Dentine microhardness after different methods for detection and removal of carious dentine tissue.

UNLABELLED: There are several methods for identifying carious dentinal tissue aiming to avoid removal of healthy dentinal tissue. OBJECTIVES: The purpose of this study was to test different methods for the detection of carious dentinal tissue regarding the amount of carious tissue removed and the remaining dentin microhardness after caries removal. MATERIAL AND METHODS: The dentin surfaces of 20 bovine teeth were exposed and half of the surface was protected with nail polish. Cariogenic challenge was performed by immersion in a demineralizing solution for 14 days. After transverse cross-section of the crown, the specimens were divided into four groups (n=10), according to the method used to identify and remove the carious tissue: "Papacárie", Caries-detector dye, DIAGNOdent and Tactile method. After caries removal, the cross-sectional surface was included in acrylic resin and polished. In a microhardness tester, the removed dentin thickness and the Vickers microhardness of the following regions were evaluated: remaining dentin after caries removal and superficial and deep healthy dentin. RESULTS: ANOVA and Tukey's test (α=0.05) were performed, except for DIAGNOdent, which did not detect the presence of caries. Results for removed dentin thickness were: "Papacárie" (424.7 ± 105.0; a), Caries-detector dye (370.5 ± 78.3; ab), Tactile method (322.8 ± 51.5; bc). Results for the remaining dentin microhardness were: "Papacárie" (42.2 ± 10.5; bc), Caries-detector dye (44.6 ± 11.8; abc), Tactile method (24.3 ± 9.0; d). CONCLUSIONS: DIAGNOdent did not detect the presence of carious tissue; Tactile method and "Papacárie" resulted in the least and the most dentinal thickness removal, respectively; Tactile method differed significantly from "Papacárie" and Caries-detector dye in terms of the remaining dentin microhardness, and Tactile method was the one which presented the lowest microhardness values.

The effectiveness of low-intensity red laser for activating a bleaching gel and its effect in temperature of the bleaching gel and the dental pulp.

STATEMENT OF THE PROBLEM: The effectiveness of low-intensity red laser for activating a bleaching gel and its effect in pulp temperature was not investigated in dental literature. PURPOSE: The objective of this study was to assess the effectiveness of low-intensity red laser for activating a bleaching gel, as well as its effect in temperature of the bleaching gel and the dental pulp. MATERIALS AND METHODS: Forty extracted bovine teeth were immersed in a solution of coffee 14 days for darkening. The initial colors were recorded by spectrophotometric analysis. The specimens were randomly distributed into two groups (N = 20): the control, which did not receive light and the experimental group that received light from an appliance fitted with three red light-emitting laser diodes (λ = 660 nm). A green-colored, 35% H(2) O(2) -based bleaching gel was applied for 30 minutes, and changed three times. After bleaching, the colors were again measured to obtain the L*a*b* values. Color variation was calculated (ΔE) and the data submitted to the non-paired t-test (5%). To assess temperature, 10 human incisors were prepared, in which one thermocouple was placed on the bleaching gel applied on the surface of the teeth and another inside the pulp chamber. RESULTS: There was a significant difference between the groups (p = 0.016), and the experimental group presented a significantly higher mean variation (7.21 ± 2.76) in comparison with the control group (5.37 ± 1.76). There was an increase in pulp temperature, but it was not sufficient to cause damage to the pulp. CONCLUSION: Bleaching gel activation with low-intensity red laser was capable of increasing the effectiveness of bleaching treatment and did not increase pulp temperature to levels deleterious to the pulp.

Absence or weak correlation between chewing side preference and lateralities in primary, mixed and permanent dentition.

OBJECTIVES: To determine whether chewing side preference (CSP) is correlated to lateralities (handedness, footedness, eyedness and earedness) in primary, mixed and permanent dentitions. DESIGN: Three-hundred subjects were divided into 3 groups: Group 1--100 children 3-5 years old, primary dentition; Group 2--100 children 6-12 years old, mixed dentition; Group 3--100 subjects 18-47 years old, permanent dentition. CSP was determined using a method developed by Mc Donnell et al. Subjects were given a piece of gum and the position of the chewing gum was recorded 7 times as right or left. Subjects were classified as 'observed preferred chewing side' (OPCS) when they performed 5/7, 6/7 or 7/7 strokes on the same side. OPCS corresponded to the CSP. Laterality tests were performed for handedness, footedness, eyedness and earedness tasks. The Chi-square (χ(2)) and phi correlation (r) tests were used to investigate significant correlations between CSP and sidedness. RESULTS: There was a significant correlation between chewing and earedness (p=0.00), although there was weak positive correlation (r=0.30) for primary dentition. There were significant correlations between chewing and handedness (p=0.02; r=0.25) and chewing and footedness (p=0.02; r=0.26), however, there were weak positive correlations for mixed dentition; there were significant correlations between chewing and handedness (p=0.02; r=0.26); chewing and footedness (p=0.00; r=0.33) and chewing and earedness (p=0.01; r=0.29); however, there were weak positive correlations for permanent dentition. CONCLUSION: It may be concluded that CSP can be significantly correlated with: earedness for primary dentition; handedness and footedness for mixed dentition; handedness, footedness and earedness for permanent dentition, but these are weak positive relationships. Future work on larger samples of left- and right-sided individuals is required to validate the findings.

Effect of dental surface treatment with Nd:YAG and Er:YAG lasers on bond strength of resin composite to recently bleached enamel.

The aim of this work is to evaluate the effect of surface treatment with Er:YAG and Nd:YAG lasers on resin composite bond strength to recently bleached enamel. In this study, 120 bovine incisors were distributed into two groups: group C: without bleaching treatment; group B: bleached with 35% hydrogen peroxide. Each group was divided into three subgroups: subgroup N: without laser treatment; subgroup Nd: irradiation with Nd:YAG laser; subgroup Er: irradiation with Er:YAG laser. The adhesive system (Adper Single Bond 2) was then applied and composite buildups were constructed with Filtek Supreme composite. The teeth were sectioned to obtain enamel-resin sticks (1 × 1 mm) and submitted to microtensile bond testing. The data were statistically analyzed by the ANOVA and Tukey tests. The bond strength values in the bleached control group (5.57 MPa) presented a significant difference in comparison to the group bleached and irradiated with Er:YAG laser (13.18 MPa) or Nd:YAG (25.67 MPa). The non-bleached control group presented mean values of 30.92 MPa, with statistical difference of all the others groups. The use of Nd:YAG and Er:YAG lasers on bleached specimens was able to improve the bond strengths of them.