Linear dimensional accuracy of stereolithographic surgical guide after chemistry and physics sterilization

OBJECTIVES

The purpose of this study was to evaluate the dimensional stability of prototyped surgical guides after autoclave and 2% glutaraldehyde sterilization processes.

MATERIAL AND METHODS

Twenty prototyped surgical guides were prepared and submitted to two sterilization processes (n = 10): Physics - sterilization by autoclave (saturated water vapor under pressure, temperature of 126 to 130 °C, pressure of 1,7 at 1.9 kgf/cm², 16 min); Chemistry - sterilization by 2% glutaraldehyde for 10 h. Six pre-established points were measured in the prototyped surgical guides, before and after sterilization, using a digital caliper rule. The comparisons were made using orthogonal contrasts using the linear model of mixed effects (random and fixed).

RESULTS

there are no significant differences between autoclave and glutaraldehyde 2% (p>0.05) there are significant differences after autoclave sterilization (p<0.05) and there are not significant differences after 2% glutaraldehyde sterilization (p>0.05).

CONCLUSION

autoclave promoted dimensional alteration of the prototyped surgical guides, and the chemical sterilization by glutaraldehyde 2% did not cause dimensional alteration of the prototype surgical guides, being a favorable choice for sterilization.

CLINICAL SIGNIFICANCE

the sterilization of surgical guides can be performed through the chemical process with 2% glutaraldehyde without changing the linear precision of the prototype surgical guides.

Influence of chlorhexidine, propolis, pulpal pressure simulation, and aging on dentin bond strength

The present study evaluated the bond strength (μTBS) of dentin treated with chlorhexidine and propolis subjected to simulated pulpal pressure (SPP) and thermocycle aging. One hundred and twenty healthy human molars were sectioned to obtain 2 mm of dentin thickness and were divided into two groups (n = 60): SPP (15 cm H₂ O) and no SPP (Control group). Dentin surfaces were conditioned with 37% phosphoric acid for 15 s and were divided according to the dentin treatment (n = 20): Control; Chlorhexidine gluconate (0.2% for 30 s) and Propolis (aqueous propolis extract for 30 s). Half of the specimens were submitted to 15,000 thermocycle aging (5 ± 2°C and 55 ± 2°C). The samples were sectioned into beams and submitted to μTBS. Data were analyzed by three-way ANOVA (SPP × Dentin treatment × Thermocycle aging) and the Tukey's tests (p < .001). With regard to the SPP, ANOVA revealed that the Control group (32.98 MPa) had significantly higher values of μTBS when compared to the SPP (29.19 MPa). With regard to Thermocycle aging, no aging (34.05 MPa) had significantly higher values of μTBS when compared to the aging (28.12 MPa). With regard to the dentin treatment, Propolis and Chlorhexidine did not statistically influence the results (p > .05). The SPP and thermocycle aging negatively influenced the bond strength between the dentin and resin; the 0.2% chlorhexidine digluconate and aqueous propolis extract solutions did not interfere in the bond strength between the resin and dentin. The use of chlorhexidine and propolis as a dental treatment may not influence the dentin bond strength, but SPP and thermocycle aging may damage the longitudinal dentin bond strength.

Adhesive systems effect over bond strength of resin-infiltrated and de/remineralized enamel

Background: The purpose of this study was to evaluate the effect of different bonding agents on bond-strength to demineralized enamel after remineralizing treatments and resin infiltration. Methods: Buccal enamel of 120 bovine incisors was polished and then were divided into five experimental groups: SE (sound enamel); DE (demineralized enamel); AS (demineralized enamel immersed in artificial saliva for eight weeks); NaF (demineralized enamel treated with 0.05% sodium fluoride solution (one minute) for eight weeks); Ic (demineralized enamel infiltrated with a low-viscosity resin (Icon-DGM). These groups were subdivided according to adhesive system used: self-etching adhesive Adper Easy One (3M/ESPE) and etch-and-rinse adhesive Single Bond (3M/ESPE). The composite resin blocks were fabricated using a Teflon matrix. A thermomechanical cycling machine was used to carry out the artificial aging of the specimens and thus were sectioned into sticks. The microtensile tests were performed using a universal testing machine at a cross-head speed of 1 mm/min. Data (in MPa) were subjected to two-way ANOVA and Tukey's tests (5%). Results: Significant differences were found for both factors tested and interactions (p<0.05). Tukey's test results of µTBS (mean ± SD) were: etch-and-rinse SE (28.79±3.93); DE (30.41±7.22); AS (29.03±3.33); NaF (29.81±4.06)a; Ic (29.47±5.5);  and self-etching SE (30.37±6.96); DE (14.62±4.47); AS (9.79±2.32); NaF (9.36±2.31); Ic (30.78±8.68).   Conclusions: Resin infiltration did not affect the bond strength of demineralized enamel for both adhesive systems tested. For etch-and-rinse adhesive, no differences were observed for the tested groups. For self-etching adhesive, only the resin-infiltrated group showed similar bond strength to sound enamel. Both etch-and-rinse and self-etching adhesive systems can be used in resin-infiltrated enamel, if a composite restoration needs to be further performed. In enamel that has undergone the de/remineralization process, the use of a total-etch adhesive might be preferable for the restorative procedure.

Mechanical-physicochemical properties and biocompatibility of catechin-incorporated adhesive resins

Several anti-proteolytic dentin therapies are being exhaustively studied in an attempt to reduce dentin bond degradation and improve clinical performance and longevity of adhesive restorations.

Influence of chlorhexidine on longitudinal bond strength to dentin: in vitro study

Objective: This study evaluated the effect of 0.2% chlorhexidine gluconate solution used as an therapeutic primer on the long-term bond strength of etch-and-rinse adhesive to dentin. Material and Methods: Bovine incisors were worn to expose an area of dentin and were divided into 2 groups: Group C (Control) - acid etching with 37% phosphoric acid + Single Bond; Group CHX (0.2% CHX) - acid etching with 37% phosphoric acid + 0.2% CHX for 30 s + Single Bond. Blocks of composite were fabricated and stored for 24 h or 6 months, sectioned into beams and submitted to microtensile tests. Results were analyzed by two-way ANOVA and Tukey tests. Results: Mean (±SD) values (in MPa) were as follow: Group CHX/24h - 41.8(±2.62)A; Group C/24h - 40.8(±3.35)AB; Group CHX/6 months – 36.4(±3.52)B; Group CHX/6 months - 26.1(±1.54)C. Conclusion: CHX improve the imediatte bond strength of resin-dentin and significantly lowered the loss of bond strength after 6 months water storage as seen in the control bonds.KeywordsTensile bond strength; Dentin; Total-etch adhesives; Chlorhexidine gluconate.

Effect of Lining Materials on Shear Bond Strength for Composite Restorations In Vitro

This study evaluated the influence of liner agents placed under resin composite restorations on shear bond strength (SBS) to dentin. A total of 40 extracted bovine incisors were used. Enamel surfaces were ground to expose a flat dentin area of 7 mm in diameter. Teeth were divided into four groups according to tested liners: Group 1 (control) used no liner; Group 2 used a resin-modified glass-ionomer cement liner (Vitrebond Plus, 3M ESPE); Group 3 used a light-activated calcium hydroxide resin liner (Ultra-Blend Plus, Ultradent); and Group 4 used a polyacrylic acid surface treatment + conventional glass-ionomer cement liner (Vidrion F, SSWhite). All groups were subjected to bonding procedures with Single Bond (3M ESPE) and 4-mm-thick buildups of resin composite were fabricated. Artificial aging was performed, and the specimens were submitted to mechanical shear testing. One-way analysis of variance (ANOVA) revealed significant differences among liners (P = .00). Group 4 showed the highest SBS. Group 1 showed significantly higher mean SBS compared with Group 3. Results showed that SBS is improved when using polyacrylic acid surface treatment + conventional glass-ionomer cement and decreased when using light-activated calcium hydroxide when compared with no liner. Polyacrylic acid surface treatment + conventional glass-ionomer cement as a liner placed under adhesion surface can improve the shear bond strength between dentin and resin, while light-activated calcium hydroxide resin should be used restrictedly in very deep cavities, because they may reduce the bond strength of the restoration submitted to masticatory forces and temperature changes in the oral environment.

Effect of chlorhexidine, green tea and egcg as therapeutic primers to increase the durability of resin-dentin bond

Objective - This study evaluated the effect of 0.2% chlorhexidine gluconate solution (CHX), green tea and active epigallocatechin-gallate (EGCG) used as therapeutic primers on the long-term bond strength of etch-and-rinse adhesive to dentin. Material and Methods - Eighty bovine incisors were worn to expose an area of dentin, that were acid-etched (37% phosphoric acid) and rinsed.  The teeth were divided into 4 groups (n = 20): Group C (Control) - Single Bond; Group CHX - 0.2% CHX for 30s + Single Bond;  Group EGCG - active EGCG gel at 10 µM for 30 s + Single Bond;  Group GT - aqueous green tea for 30s + Single Bond. Blocks of composite were fabricated and stored for 24 h or 6  months, sectioned into beams  and  submitted  to  microtensile  tests. Results  were  analyzed  by  two-way  ANOVA  and Tukey’s test (5%).  Results - Mean (±SD) values (in MPa) were as follow: CHX (24 h) – 41.76 (±2.62); C (24 h) - 40.81 (±3.35); GT (24 h): 37.38(2.98); CHX (6 months) - 36.04 (±3.52); EGCG (24h) - 35.91 (±4.82); EGCG (6 months) - 35.75 (±4.44); GT (6 months) - 31.95 (±3.40); C (6 months): 30.05 (±1.54). Conclusion - EGCG produced resin-dentin bonds that did not change after 6 months water storage but it decreased the immediate bond strength when compared to control and chlorhexidine groups.Keywords: Tensile bond strength; Dentin; Total-etch adhesives; Chlorhexidine gluconate; Green tea.

CVD and diamond tips: can then influence the bond strength of a total-etch adhesive to dentin?

Data (MPa) were analyzed by two-way ANOVA (Surface treatment X Etching time) and Tukey's test (5%). Results and conclusions: Surface treatment with CVD tips (27.70 ± 4.04a) produced significantly higher bond strength values compared to diamond tips (23.96 ± 5.83b), and 5 second etching time on dentin produced similar bond strength values when compared to 10 and 15 second etching times. Objectives: Evaluate the microtensile bond strength of a total-etch adhesive to dentin, using a CVD tip and a diamond tip to use in dentin preparation and varying the etching time. Material and method: The dentin from the buccal face of sixty bovine teeth was exposed and prepared using two different methods (n=30): Group 1 (DT) – a diamond tip on a high-speed handpiece; and Group 2 (CVD) – a CVD tip on an ultrasonic handpiece. Each group used 37% phosphoric acid and was divided into three subgroups, according to the etching time (n=10): Subgroup 5 - 5 seconds; Subgroup 10 - 10 seconds; and Subgroup 15 - 15 seconds. The teeth were restored with Single Bond adhesive and the composite resin Herculite Classic. The specimens were subjected to thermomechanical wear (mechanical cycling/100.000 cycles, thermal cycling/1.000 cycles). Stick-like specimens were obtained and submitted to a microtensile test in a universal testing machine.

Nd:YAG laser influence on the hybridization quality, employing total-etching or self-etching adhesives: sem analysis

Background: The application of Nd:YAG laser on dentin with the adhesive system non-polymerized can influenced the quality of hybrid layer formed. Objectives: The aim of this study is to assess through analysis by scanning electronic microscopy (SEM), the Nd:YAG laser influence on the hybridization quality, using conventional Adper Single Bond (SB) or self-etching Clearfil SE Bond-Kuraray (CSEB) adhesives. Methods: Nine bovine incisors were treated on their incisal with SB and with CSEB in their cervical portion. They were divided into 3 groups with 6 specimens in each and treated as follows; G1- adhesive system and polymerization; G2- adhesive system, laser (60mJ/pulse) and polymerization; G3- adhesive system, laser (140mJ/pulse) and polymerization. All samples were restored with composite resin (Filtek Z350-3M). The thickness, the presence of failures (gap/porosity) and tags/microtags in the hybrid layer were analyzed using the SEM. The data were submitted to ANOVA and Tukey statistical tests 5%. Results: The highest average of hybrid layer thickness (1.89±0.15) was observed for G3 and the smallest was observed for G1-CSEB (1.36±0.14). The multiple comparison of ratio test showed that the smallest prevalence of failures was for G3-CSEB and the best performance for the presence of tags/microtags was found for G2-SB. Conclusion: Independent of the adhesive system used, the Nd:YAG laser, according to the parameter applied, had a positive influence on the hybridization quality.

Can Nd:YAG laser irradiated on dentin with non-polymerized adhesives influence the durability of bond strength and micromorfology of hybrid layer?

Objective: This study evaluated the durability of bond strength to dentin using total-etch (Single Bond /SB) and self-etch (Clearfil SE Bond/CSEB) adhesives associated with Nd:YAG Laser irradiation through the unpolymerized adhesives. Also, this study evaluated micromorfological chances in hybryd layer after 12 months wter storage.Material and Methods: Bovine incisors were worn to expose a dentin area and were divided into 4 groups (n = 15):Group 1 (Control) – SB + photopolymerization; Group 2 (Control) – CSEB + photopolymerization; Group 3 (Experimental/Laser) - SB + Nd:YAG laser (149.28 J/cm2) + photopolymerization; Group 4 (Experimental/Laser) – CSEB + Nd:YAG (149.28 J/cm2) + photopolymerization.Composite blocks were fabricated; intact teeth were stored for 24 h or 12 months (12 m), sectioned into beams and submitted to microtensile bond strength tests.Two teeth from each group (n = 2) were prepared for SEM analysis. Results: Results were analyzed by three-way ANOVA (adhesive, Technique and storage time) and Tukey tests (0.05). Results: For interaction Adhesive X Technique X Storage time the mean values (MPa) were:SB/Control/24h = 34.05(±6.14)a; CSEB /Control/24h = 32.12(±5.26)a; SB/Laser/24h = 30.54(±5.94)a; CSEB/Laser/24h = 29.45(±5.11)a; SB/Control/12m = 29.36(±5.57)a; CSEB/Control/12m = 29.09(±8.84)a; SB/Laser/12m = 22.06(±3.77)b; CSEB/Laser/12m = 13.35(± 3.35)c. Conclusion: SEM showed evident areas of micromorphological alterations on lased samples after 12 months water storage with accelerated degradation of the hybrid layer.Bond strength decreased when dentin irradiated with the Nd:YAG laser through unpolymerized adhesives was stored in water for 12 months.Laser irradiation of dentin through unpolymerized self-etch adhesive significantly reduced bond strength when compare with total-etch adhesive after 12 months water storage. Keywords:Dental adhesives; Dentin bonding; Nd yag; Tensile strength.

Mechanical properties of the bond interface associated with nd:yag laser

ABSTRACTObjective:This study evaluated the hardness and modulus of elasticityof the dentin bond interface using total-etch (Single Bond /SB) and self-etch (Clearfil SE Bond/CSEB) adhesives associated with Nd:YAG Laser irradiation through the unpolymerized adhesives.Material and Methods: The occlusal surfaces of 12 human third molars were ground until superficial dentin was exposed. A standardized circular cavity was performed on the occlusal surface. Specimens were sectioned in the mesio-distal direction, and the 24 hemi-crowns were divided into four groups: Group SB/Control - SB + polymerization; Group SB/Laser - SB + Nd:YAG laser (174.16J/cm2/60s/non-contact) + polymerization; Group CSEB/Control – CSEB + polymerization; Group CSEB/Laser - CSEB + Nd:YAG laser (174.16J/cm2/cm2/60s/non-contact) + polymerization. Composite were placed in the cavities and polymerized. The specimens were immersed in distilled water and stored in an oven at 37ºC for 24h and then submitted to nanoindentation in a Nano Indenter® XP appliance. Results: The results were submitted to ANOVA, Tukey’s test and Student's-t test (p < 0.05). Conclusão: It was concluded that the application of the Nd:YAG laser in both adhesive systems did not changed the hybrid layer hardness; however, it increases the modulus of elasticity in the hybrid layer for both adhesives tested and it maybe preserves the integrity of the adhesive interface and its durability. Clinical relevance: The application of Nd:YAG laser prior to photopolymerization of adhesive systems can increase the modulus of elasticity in the hybrid layer and may contribute to stress distribution in the adhesive interface during the polymerization preserving the integrity of the adhesive interface and its durability.

What is the best protocol for bonding resin-modified glass ionomer cement to composite resin?

Objective: The objective of this study was to evaluate the bond strength of resin-modified glass ionomer cement (RMGIC) to composite resin considering the use of conventional and self-etching adhesive systems. Material and Methods: 60 RMGIC blocks (Riva, SDI) measuring 4 x 4 x 4 mm. were constructed. On the blocks, the application of different protocols of adhesive systems (n = 10) was carried out: Group 1 (Control) - without application of adhesive agent; Group 2 - 37% phosphoric acid + conventional adhesive agent Single Bond 2; Group 3 - conventional adhesive agent Single Bond 2; Group 4 – conventional adhesive agent Scotch Bond Multi-Purpose; Group 5 - self-etching adhesive Clearfil SE Bond; Group 6: self-etching adhesive Optibond Allin-One. Next, resin composite blocks measuring 4 x 4 x 4 mm were constructed (Venus, Heraeus Kulzer). The specimens were cut to obtain sticks which were submitted to microtensile bond strength test in a universal testing machine. The data were submitted to ANOVA and Tukey test (5%). Results: ANOVA showed a value of p < 0.05, which indicated significant differences between the groups (in Mpa): Group 2 - 32.83; Group 5 - 31.2; Group 3 - 25,15b; Group 6 - 22.92; Group 4 - 22.15; Group 1 - 13.84. The analysis of fracture mode demonstrated that there was a predominance of adhesive and mixed fractures for all groups. Conclusion: The protocols of acid etching + conventional adhesive system Single Bond 2 (Group 2) or self-etching adhesive system Clearfil SE Bond (Group 5) increased the bond strength of RMGIC to the composite resin. The presence of an adhesive layer between the two materials tended to improve the bonding of RMGIC to composite resin.

Clinical performance of topical sodium fluoride when supplementing carbamide peroxide at-home bleaching gel

This clinical study evaluated the use of 0.11% topical sodium fluoride (SF) desensitizing agent to treat tooth sensitivity during a nightguard tooth whitening procedure. Thirty-two subjects bleached their teeth with 10% carbamide peroxide (CP) gel using an at-home bleaching technique with custom trays. During bleaching treatment, subjects were divided into 2 groups (n = 16). The subjects in Group 1 received a topical gel containing 0.11% SF; the subjects in Group 2 received a placebo gel (PG). Each subject was instructed to place the gel in his/her bleaching tray for 30 min every day following bleaching treatment. Results showed the use of SF did not affect the whitening efficacy of the 10% CP gel. Subjects who received the PG had significantly higher tooth sensitivity when compared with subjects who received SF (P < 0.00). The use of daily 0.11% SF after 10% CP bleaching gel reduced tooth sensitivity during the bleaching treatment.

Analysis of flexural strength of composite resins polymerized by 2nd and 3rd generation leds

Objective: This study aimed to investigate the mechanical properties of three composite resins using 2nd and 3rd generation LED-based light-curing devices. Material and Methods: Sixty specimens distributed according to the type of resin(Group Z350 - nanoparticle composite resin [Filtek Z350 / 3M ESPE]; Group AP - microhybrid composite Amelogen Plus/Ultradent; Group DF - Group composite resin Durafil l/Heraeus Kulzer), and the light-curing device(Group 2ndG - 2nd generation LED-based curing unit at power density of 500 mW / cm2; Group 3rdG - 3rd generation LED-based curing unit at power density of 1100 MW/cm2).The specimens were stored in a dark, dry container at 37 °C in an incubator for 24 h and submitted to the mini-flexural test on universal test machine (EMIC) to determine the elastic modulus and flexural strength using a three-point test.The data were submitted to two-way ANOVA (Resin Composite X LED) and Tukey test (5%).Results: Concerning to flexural strength (in MPa), ANOVA showed significant in Tukey test for the interaction between the factors: Group Z350/3rdG - 105.36a; Group AP/3rdG – 81.49ab; Group DF/3rdG – 66.43bc; Group AP/2ndG – 66.13bc; Group DF/2ndG: 60.61bc; Group Z350/2ndG: 47,19c. With regard to the modulus of elasticity (in GPa), the results obtained were: Factor resin composite - Group Z350 (8.85a) > Group AP (7.61b) > Group DF (1.94c); Factor LED - Group 3rdG (7.13a) > Group 2ndG (5.14b). Conclusion:It was concluded that the 3rd generation LED (1100 mw/cm2) significant increased the means of the flexural properties of composites. It was also concluded that the result of flexural properties of compositesdepends on the resin material tested. Keywords: Composite resin; Flexural strength; Modulus of elasticity.

Longitudinal Evaluation of Bond Strength to Enamel of Dental Adhesive Systems Associated with Nd:YAG Laser

OBJECTIVES

This study evaluated the durability of bond strength to enamel using total-etch (Single Bond/SB) and self-etch (Clearfil SE Bond/CSEB) adhesives associated with neodymium:yttrium-aluminu-garnet (Nd:YAG) laser irradiation through the uncured adhesives.

METHODS

Bovine incisors were worn to expose an area of enamel and were divided into four groups: group 1 (control) SB + polymerization; group 2 (control) CSEB + polymerization; group 3 (laser) - SB + Nd:YAG laser (174.16 J/cm(2)) + polymerization; and group 4 (laser) CSEB + Nd:YAG (174.16 J/cm(2)) + polymerization. Blocks of composite were fabricated and stored for 24 hours or 12 months, sectioned into beams, and submitted to microtensile tests. Results were analyzed by three-way analysis of variance (ANOVA) (adhesive, technique, and storage time) and Tukey tests.

RESULTS

ANOVA revealed significant differences for adhesive × technique and technique × storage time (p<0.05). The mean values (MPa) for interaction adhesive × technique (standard deviation) were as follows: SB/control = 35.78 (6.04)a; SB/laser = 26.40 (7.25)b, CSEB/control = 26.32 (5.71)b, CSEB/laser = 23.90 (7.49)b. For interaction technique × storage time the mean values were as follows: control/24 hours = 32.58 (6.49)a; control/12 months = 29.52 (8.38)a; laser/24 hours = 29.37 (5.71)a; laser/12 months = 20.92 (6.5)b. Groups with the same letters showed no statistically significant differences.

CONCLUSION

Scanning electron microscope analysis showed evident areas of micromorphological alterations in lased samples after 12 months of water storage. Nd:YAG laser irradiation of enamel through unpolymerized total-etch adhesive significantly reduced bond strength compared with the control. Bond strength decreased when enamel samples irradiated with Nd:YAG laser through unpolymerized adhesives were stored in water for 12 months.

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.

Influence of adhesive system in bond strength of fiber glass posts to radicular dentin using dual cure resin cement

The purpose of this study was to evaluate the bond strength between root dentin and glass fiber posts cemented with dual cure resinous cement associated with the conventional and self-etching adhesive systems. Twenty-four single-rooted human teeth were selected, and the crowns were removed at the cement enamel junction. The roots received biomechanical preparation and obturation followed by the intraradicular preparation compatible with a drill diameter of the glass fiber posts. The roots were divided into two groups, according to cementation protocol (n-12): Group 1 - etched with 37% phosphoric acid for 30 seconds, total-etch adhesive system Single Bond (3M ESPE)  and Enforce  resinous cement (Dentsply); Group 2 – self-etch adhesive system One Up Bond F (Tokuyama)  and Enforce  resinous cement (Dentsply). After the posts cementation, the roots were kept at 370 C for one week, and submitted to pull out test on the universal testing machine Emic to a traction speed of 1 mm/min. Data in MPa were submitted to the statistical t-test (5%). The t-test showed significant differences between the two groups (p=0.003). The average values in MPa (±standard-deviation) were: Group 1: 5.28(±3.25), Group 2: 10.05(±3.78). Enforce associated with the self-etch adhesive system One Up Bond F showed significantly higher bond strength values than Group 1 - Enforce associated with the total-etch adhesive system Single Bond.

Surface roughness of indirect composites using different polishing systems

<p><strong>Objective: </strong>The aim of this study was to evaluatethe surface roughness of indirect composites afterpolishing with aluminum oxide (Al2O3) discs. <strong>Materialand Methods</strong>: One-hundred and eighty specimenswere confectioned with 6 indirect composites using aprefabricated matrix, resulting in six groups (n-30):Group SO - Solidex, Group SI - Signum, Group SF- Sinfony, Group OP - Opallis; Group RE - Resilab,Group EP - Epricord, Group AD - Adoro. Each groupwas divided into three subgroups according to thepolishing (n-10): Subgroup C (Control) - withoutpolishing (polyester strip); Subgroup S - polishingwith Sof-Lex discs; Subgroup T - polishing with TDVdiscs. The surface roughness was measured with aprofilometer. <strong>Results: </strong>The results were analyzed byANOVA and Tukey tests (5%), resulting in p = 0.00.The mean values (±standard-deviation) measured inRa (μm) for each Group/Subgroup were: RE/C - 0.14(± 0.14) a; EP/C - 0.18 (± 0.46) ab; SO/C - 0.24 (±0.22) abc; SF/S - 0.24 (± 0.17) abc; SF/C - 0.26 (±2.54)abc; SI/C - 0.30 (± 0.34)abcd; SO/T - 0.33(±0.42) abcd; AD/S - 0.34(± 0.88)abcd; AD/C - 0.37(±0.60)ab; SI/S - 0.37(± 1.39)bcd; SO/S - 0.43(± 0.26)cd; EP/S – 0.44 (± 1.02) cd; RE/S - 0.54(±2.02) de;SI/T - 0.65(± 0.88)ef; RE/T - 0.83 (± 0.54) fg; SF/T- 0.85 (± 0.21) fg; AD/T - 0.88 (± 1.74) fg; EP/T- 0.91(± 0.89) g. <strong>Conclusion: </strong>It is concluded thatpolyester strip resulted in significantly lowest surfaceroughness; polishing with TDV discs resulted insignificantly higher surface roughness compared toSof-Lex discs and that the surface roughness resultsdepend on the composite tested.</p><p>Keywords<br />Composite resins; Dental polishing; Biofilms.</p>

Microtensile test in dental research. controversial aspects in statistical analysis (experimental unit and premature failures)

Aims: The aim of this study was to present the controversial aspects in performing inferential statistical analysis with regard to selection of the experimental unit and procedures adopted in the case of pre-test failures.Material and Method: Eighty-seven dissertations and theses in the field of dentistry were evaluated, in which microtensile testing available at three public Universities in the State of São Paulo were performed, namely:  School of Dentistry, USP; School of Dentistry, Unesp (Araraquara and São José dos Campos) and the Piracicaba School of Dentistry (Unicamp).Results: As regards the experimental unit, 34 (39.08%) theses and/or dissertations used the “stick” and 53 (60.91%) the “tooth/block” type. With regard to pre-test failures, 9 (10.34%) theses and/or dissertations  attributed the value “0”, 6 (6.89%) disregarded the sticks,  2 (2.29%) attributed the minimum value of 2 MPa, 1 (1,14%) the minimum value of 4 MPa, 1 (1.14%) attributed half the minimum value of the group and 68 (78.16%) did not mention the occurrence of pre-test failures.Conclusion: As regards the experimental unit, at present the experimental unit is considered the tooth (or ceramic bloc) and not the stick. With regard to pre-test failures, the following are considered: Attribution of a minimum bond strength value under the experimental condition or in the group considered; expressing the number and percentage of cases of failures under each experimental condition; which failures were included in the statistical analysis and making a comparison between the analysis with exclusion of the sticks and analysis without inclusion of the sticks.

Influence of Nd:YAG laser on the bond strength of self-etching and conventional adhesive systems to dental hard tissues

PURPOSE

The aim of this study was to investigate the influence of Nd:YAG laser on the shear bond strength to enamel and dentin of total and self-etch adhesives when the laser was applied over the adhesives, before they were photopolymerized, in an attempt to create a new bonding layer by dentin-adhesive melting.

MATERIAL AND METHODS

One-hundred twenty bovine incisors were ground to obtain flat surfaces. Specimens were divided into two substrate groups (n=60): substrate E (enamel) and substrate D (dentin). Each substrate group was subdivided into four groups (n=15), according to the surface treatment accomplished: X (Xeno III self-etching adhesive, control), XL (Xeno III + laser Nd:YAG irradiation at 140 mJ/10 Hz for 60 seconds + photopolymerization, experimental), S (acid etching + Single Bond conventional adhesive, Control), and SL (acid etching + Single Bond + laser Nd:YAG at 140 mJ/10 Hz for 60 seconds + photopolymerization, experimental). The bonding area was delimited with 3-mm-diameter adhesive tape for the bonding procedures. Cylinders of composite were fabricated on the bonding area using a Teflon matrix. The teeth were stored in water at 37°C/48 h and submitted to shear testing at a crosshead speed of 0.5 mm/min in a universal testing machine. Results were analyzed with three-way analysis of variance (ANOVA; substrate, adhesive, and treatment) and Tukey tests (α=0.05). ANOVA revealed significant differences for the substrate, adhesive system, and type of treatment: lased or unlased (p<0.05). The mean shear bond strength values (MPa) for the enamel groups were X=20.2 ± 5.61, XL=23.6 ± 4.92, S=20.8 ± 4.55, SL=22.1 ± 5.14 and for the dentin groups were X=14.1 ± 7.51, XL=22.2 ± 6.45, S=11.2 ± 5.77, SL=15.9 ± 3.61. For dentin, Xeno III self-etch adhesive showed significantly higher shear bond strength compared with Single Bond total-etch adhesive; Nd:YAG laser irradiation showed significantly higher shear bond strength compared with control (unlased).

CONCLUSION

Nd:YAG laser application prior to photopolymerization of adhesive systems significantly increased the bond strength to dentin.

A comparison of methods used to determine chewing side preference in deciduous, mixed and permanent dentitions

Objective: The purpose of this study was to determine whether ‘chewing side preference’ (CSP) is correlated to ‘chewing side preference during the first chewing cycle’ (CSP1ºC) in the deciduous, mixed and permanent dentitions.Methods: Three-hundred subjects were divided in 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 McDonnell et al. (2004). 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. CSP1ºC was determined using a method developed by Hoogmartens and Caubergh (1987). Subjects were given five pieces of gum and the position of the chewing gum at first chewing cycle was recorded as right or left. For each subject, an index (I) was performed. The Chi-square (X2) and phi correlation (r) tests were used to investigate signi?cant correlations between CSP and CSP1ºC. Results: There was a strong positive and significant correlation between CSP and CSP1ºC for primary dentition (p=0.000; r=0.82), for mixed dentition (p=0.000; r=0.81) and a very strong positive and significant correlation for permanent dentition (p=0.000; r=0.90). Conclusion: CSP can be significantly correlated to CSP1ºC for primary dentition, mixed dentition and permanent dentition, and these are strong positive relationships for primary and mixed dentitions and very strong positive relationship for permanent dentition.

Two-year Clinical Performance of Self-etching Adhesive Systems in Composite Restorations of Anterior Teeth

Objective

The aim of this study was to evaluate the two-year clinical performance of Class III, IV, and V composite restorations using a two-step etch-and-rinse adhesive system (2-ERA) and three one-step self-etching adhesive systems (1-SEAs).

Material and Methods

Two hundred Class III, IV, and V composite restorations were placed into 50 patients. Each patient received four composite restorations (Amaris, Voco), and these restorations were bonded with one of three 1-SEAs (Futurabond M, Voco; Clearfil S3 Bond, Kuraray; and Optibond All-in-One, Kerr) or one 2-ERA (Adper Single Bond 2/3M ESPE). The four adhesive systems were evaluated at baseline and after 24 months using the following criteria: restoration retention, marginal integrity, marginal discoloration, caries occurrence, postoperative sensitivity and preservation of tooth vitality. After two years, 162 restorations were evaluated in 41 patients. Data were analyzed using the χ2 test (p&lt;0.05).

Results

There were no statistically significant differences between the 2-ERA and the 1-SEAs regarding the evaluated parameters (p&gt;0.05).

Conclusion

The 1-SEAs showed good clinical performance at the end of 24 months.

Oral Health Longitudinal Evaluation of students from a public school after guidance and implementaion of preventitive measures

Objective: To assess longitudinally the DMFT, plaque and gingival rates of children and teenagers from a public school in São José dos Campos, Brazil, after performing a preventive and motivational program through the University Extension program of School of Dentistry of Institute of Science and Technology of São José dos Campos – UNESP. Materials and Methods: 300 students were randomly selected and divided into three groups, Group 1: 100 children from 2nd to 5th grade of elementary school, Group 2: 100 children from 6th to 9th grade of elementary school; Group 3: 100 teenagers from first to third year of high school. A questionnaire was used to evaluate knowledge about oral habits and general oral health of students. Clinical examinations were performed to assess the gingival, DMFT and plaque index in the initial time (t0), 1 year (t1) and 2 years (t2). The questionnaire and clinical examination results led to implementation of a scheme to promote oral health throughout the school years. The collected data were statistically analyzed. Results: Mean values for DMFT were: Group 1: t0 = 2.3 / t1 = 2.28 / t2 = 1.88, group 2: t0 = 1.81 / t1 = 1.56 / t2 = 1.51 and Group 3: t0 = 1.92 / t1 = 2.61/ t2 = 1.86; for dental plaque index: group 1: t0 = 3.83/ t1 = 2.62/ t2 = 2.30, group 2: t0 = 2.06 / t1 = 3.24 / t2 = 1.39; Group 3: t0 = 2.27 / t1 = 0.94 / t2 = 0.8, and the gingival index: group 1: t0 = 1.31 / t1 = 0.79 / t2 = 0.96, group 2: t0 = 1.27 / t1 = 0.84 / t2 = 0.38; group 3: t0 = 1.21 / t1 = 0.82 / t2 = 0.23. Conclusion: There was a significant decrease in all evaluated indexes after 2 years of program, confirming thus the importance of systematic implementation of preventive measures.

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.

Influence of Different Surface Treatments on Bond Strength of Resin Composite Using the Intrinsic Characterization Technique

Objective: This study evaluated the influence of different surface treatments on the resin bond strength/light-cured characterizing materials (LCCMs), using the intrinsic characterization technique. The intrinsic technique is characterized by the use of LCCMs between the increments of resin composite (resin/thin film of LCCM/external layer of resin covering the LCCM).

Materials and Methods: Using a silicone matrix, 240 blocks of composite (Z350/3M ESPE) were fabricated. The surfaces received different surface treatments, totaling four groups (n=60): Group C (control group), no surface treatment was used; Group PA, 37% phosphoric acid for one minute and washing the surface for two minutes; Group RD, roughening with diamond tip; and Group AO, aluminum oxide. Each group was divided into four subgroups (n=15), according to the LCCMs used: Subgroup WT, White Tetric Color pigment (Ivoclar/Vivadent) LCCM; Subgroup BT, Black Tetric Color pigment (Ivoclar/Vivadent) LCCM; Subgroup WK, White Kolor Plus pigment (Kerr) LCCM; Subgroup BK, Brown Kolor Plus pigment (Kerr) LCCM. All materials were used according to the manufacturer's instructions. After this, block composites were fabricated over the LCCMs. Specimens were sectioned and submitted to microtensile testing to evaluate the bond strength at the interface. Data were submitted to two-way analysis of variance (ANOVA) (surface treatment and LCCMs) and Tukey tests.

Results: ANOVA presented a value of p&lt;0.05. The mean values (±SD) for the factor surface treatment were as follows: Group C, 30.05 MPa (±5.88)a; Group PA, 23.46 MPa (±5.45)b; Group RD, 21.39 MPa (±6.36)b; Group AO, 15.05 MPa (±4.57)c. Groups followed by the same letters do not present significant statistical differences. The control group presented significantly higher bond strength values than the other groups. The group that received surface treatment with aluminum oxide presented significantly lower bond strength values than the other groups.

Conclusion: Surface treatments of composite with phosphoric acid, diamond tip, and aluminum oxide significantly diminished the bond strength between composite and the LCCMs.

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.

Prevalence of chewing side preference in the deciduous, mixed and permanent dentitions

AIM

This study evaluated the prevalence of the chewing side preference (CSP) in the deciduous, mixed and permanent dentitions.

MATERIALS AND METHODS

Three-hundred subjects were divided in three groups (n = 100): Group 1 - children with deciduous dentition; group 2-children with mixed dentition; group 3 - subjects with permanent dentition. The CSP was determined using a direct method (visual observation) developed by McDonnell et al. (2004). Descriptive statistic was used to observe the prevalence of CSP. The Pearson's Chi-square was used to investigate signicant associations between gender, presence of CSP and preferred side (right/left).

RESULTS AND CONCLUSION

Eighty-seven percent of group 1 had a CSP. Eighty-two percent of group 2 had a CSP. Seventy-six percent of group 3 had a CSP. There was no statistically significant association between presence of CSP and gender in all groups. There was no statistically significant association between preferred side (right/left) and gender in all groups.

CLINICAL SIGNIFICANCE

There is a higher prevalence of subjects in deciduous, mixed and permanent dentition that presented chewing side preference. The early diagnosis of the presence of chewing side preference can prevent the unilateral chewing pattern with prophylactic therapy applied to the first teeth (deciduous).

The Influence of Chemical Activation on Tooth Bleaching Using 10% Carbamide Peroxide

If a chemical agent were able to accelerate the effects of bleaching agents on tooth structure, one could reduce treatment time or diminish the daily time spent on the bleaching procedures.

pH-changes during intracoronal bleaching: an in vivo study

OBJECTIVES

This study aimed to measure pH changes during 14 days intracoronal bleaching with hydrogen peroxide/sodium perborate and carbamide peroxide/sodium perborate.

MATERIALS AND METHODS

Twenty patients presenting endodontically treated central maxillary incisors with color alterations were divided in two groups (n = 10): Group CP + SP: 37% carbamide peroxide + sodium perborate paste; Group HP + SP: 30% hydrogen peroxide + sodium perborate paste. The pH values were measured using a digital microprocessor at different times: Baseline, 2, 7 and 14 days. Data were analyzed with two-way ANOVA followed by Tukey's test (α = 0.05).

RESULTS

ANOVA showed p < 0.00 which indicated significant difference between the groups. The mean values (± sd) and the results of the Tukey´s test were: HP + SP/14 days-7.98 (±0.58)a; HP + SP/7 days-8.59 (±0.18)b; HP + SP/2 days- 8.83 (±0.32)bc; HP + SP/Baseline-8.83 (±0.01)bc; CP + SP/ Baseline-8.89 (±0.01)bc; CP + SP/14 days-9.11 (±0.58)cd; CP + SP/7 days-9.54 (±0.16)de; CP + SP/2 days-9.66 (±0.08) de. The group HP + SP resulted in significantly lower pH values compared with group CP + SP.

CONCLUSION

It can be concluded that both associations showed alkaline pH values; however, there was significant reduction in the pH values of the 30% hydrogen peroxide associated with sodium perborate after 14 days.

CLINICAL SIGNIFICANCE

The association of hydrogen peroxide and carbamide peroxide with sodium perborate paste presented alkaline characteristics during the 14-day evaluated period. Thus, regarding pH changes, both associations can be considered safe as intracoronal bleaching agents.

Assessment of color fidelity of several composite resins compared to their Vita Classical shade registration

This study compared the color fidelity of different composite resins with their registration in the Vita Classical Shade Guide. Using a prefabricated Teflon mold, 120 specimens were divided into four groups (n = 30), according to the resin tested. Three subgroups (n = 10) were prepared for each resin group; these subgroups tested enamel shade, dentin shade, and enamel and dentin shade. Three measurements were performed to verify whether the tooth shade matched that of the Vita Classical Shade Guide. The color was evaluated and the shade variations were calculated. The data were submitted to a three-way ANOVA test (time, color match, and composite type), followed by Tukey's test. It was concluded that all composite resins showed color differences in relation to the Vita Classical Shade Guide.

Effect of carbamide peroxide bleaching gel concentration on the bond strength of dental substrates and resin composite

PURPOSE

This study evaluated the effect of bleaching gel containing 10%, 15% and 20% carbamide peroxide (CP) on the bond strength of dental enamel or dentin and resin composite restorations.

METHODS

The buccal surfaces of 12 bovine tooth crowns were conditioned with 37% phosphoric acid, and the adhesive resin Single Bond 2 and the resin composite Filtek Z350 were used to perform the restorations. The blocks were sectioned to obtain bar specimens. Each specimen group (enamel-E, dentin-D) was divided into four subgroups (n=15): S-artificial saliva; 10-10% CP bleaching; 15-15% CP bleaching; 20-20% CP bleaching. CP was applied for six hours daily for two weeks. The specimens were submitted to the sigma test in a universal testing machine. The data were analyzed by one-way ANOVA and the Tukey post-hoc test and a correlation analysis (r) was performed.

RESULTS

For Group E, the mean value (+/- standard-deviation) was 21.86 (+/- 6.03)a, 18.91 (+/- 8.31)ab, 15.43 (+/- 7.44)b and 10.6 (+/- 4.94)c for ES, E10, E15 and E20, respectively. For Group D, the a values were 34.73 (+/- 4.68)a, 35.12 (+/- 13.43)a, 29.67 (+/- 6.84)ab and 24.56 (+/- 6.54)b for DS, D10, D15 and D20, respectively. A negative correlation between the CP concentration and mean values was observed for both the enamel (r=-0.95) and dentin (r=-0.85) groups.

CONCLUSION

In the current study, the bond strength of the restoration to enamel and the restoration to dentin were influenced by the application of CP and was dependent on the CP concentration in the bleaching gel.

Clinical evaluation of two packable resin-based composite restorations: a three-year report

This randomized clinical trial sought to evaluate the performance of two packable composites over a period of 36 months. A total of 39 Class I and II restorations were placed in the permanent teeth of 20 patients. Using United States Public Health Services criteria, two investigators evaluated the restorations immediately after placement and again after 12 and 36 months, examining color match, marginal discoloration, marginal integrity, recurrent caries, proximal contact, anatomical shape, surface texture, and postoperative sensitivity. It was concluded that the packable composites evaluated showed satisfactory clinical performance after three years.

Longitudinal bond strength evaluation using the deproteinized dentin technique

This study evaluated bond strength to dentin as a result of storage time for conventional adhesive systems (with or without collagen) that had been deproteinized with 10% sodium hypochlorite (NaOCl). For this study, 72 human molars were sectioned in a mesiodistal axial plane and embedded in acrylic resin; at that point, the vestibular and lingual surfaces were worn down with abrasive paper. Acid etching was performed for 15 seconds (using 37% phosphoric acid) and the specimens were divided into 12 groups (n = 6), depending on the adhesive system used, the dentin treatment performed, and the length of evaluation (24 hours or six months). A resin composite was inserted over the prepared area with the aid of a metal matrix. Following a mechanical shear test, fractured surfaces were analyzed by stereomicroscope and the data were submitted to ANOVA and Tukey's test. It was concluded that the dentin deproteinization treatment with 10% NaOCl improved the bond strength in five of the six groups. The bond strength after 24 hours was significantly higher than the bond strength measured after six months. Of the three adhesive systems tested in this study, DenTASTIC UNO demonstrated the lowest bond strength.

Effects of resinous monomers used in restorative dental modeling on the cohesive strength of composite resin

PURPOSE

The purpose of this study was to evaluate the cohesive strength of the composite using different resinous monomers to lubricate instruments used in the Restorative Dental Modeling Insertion Technique (RDMIT).

MATERIALS AND METHODS

The composite specimens were made by usinga prefabricated Teflon device. Different resinous monomers were used at the interface to lubricate the instruments, for a total of 72 specimens divided into 6 groups: (1) control group, no resinous monomer was used; (2) Composite Wetting Resin; (3) C & B Liquid; (4) Scotchbond Multi-Purpose Adhesive; (5) Adper Single Bond Adhesive; (6) Prime & Bond NT. Specimens were submitted to the circular area tensile test to evaluate the cohesive strength at the composite interfaces. Data were analyzed using ANOVA and Tukey's test (alpha = 0.05).

RESULTS

ANOVA showed a value of p < 0.0001, which indicated thatthere were significant differences amongthe groups. The means (SD) for the different groups were: Adper Single Bond Adhesive: 26 (12) a; control group: 28 (3) ab; Prime & Bond NT: 32 (12) ab; Composite Wetting Resin: 36 (9) abc; C&B Liquid: 38 (7) bc; Scotchbond Multi-Purpose Adhesive: 46 (10) c. Groups denoted with the same letters were not significantly different. Only Scotchbond Multi-Purpose Adhesive, used for direct restorations, had a statistically significantly higher bond strength than the control group, Adper Single Bond Adhesive, and Prime & Bond NT. Adper Single Bond with Adhesive showed a statistically significantly lower mean value than C & B Liquid.

CONCLUSION

The results of this study indicate that the resinous monomers used for lubricating the instruments in the RDMIT did not alter the mechanical properties of the composite, and therefore did not reduce the cohesive bond strength at the composite interfaces.