Abstract: The purpose of this study was to assess bond strength of three self-etching and two total-etch adhesive systems bonded to primary tooth enamel and dentin. MATERIALS AND METHODS: Forty extracted primary human molars were selected and abraded in order to create flat buccal enamel and occlusal dentin surfaces. Teeth were assigned to one of the adhesive systems: Adper Scotch Bond Multi Purpose, Adper Single Bond 2, Adper Prompt L-Pop, Clearfil SE Bond and AdheSE. Immediately to adhesive application, a composite resin (Filtek Z250) block was built up. After 3 months of water storage, each sample was sequentially sectioned in order to obtain sticks with a square cross-sectional area of about 0.72 mm2. The specimens were fixed lengthways to a microtensile device and tested using a universal testing machine with a 50-N load cell at a crosshead speed of 0.5 mm/min. Microtensile bond strength values were recorded in MPa and compared by Analysis of Variance and the post hoc Tukey test (a = 0.05). RESULTS: In enamel, Clearfil SE Bond presented the highest values, followed by Adper Single Bond 2, AdheSE and Adper Scotch Bond Multi Purpose, without significant difference. The highest values in dentin were obtained with Adper Scotch Bond Multi Purpose and all other adhesives did not present significant different values from that, except Adper Prompt L-Pop that achieved the lowest bond strength in both substrates. Adper Scotch Bond Multi Purpose and Adper Single Bond 2 presented significantly lower values in enamel than in dentin although all other adhesives presented similar results in both substrates. CONCLUSIONS: contemporary adhesive systems present similar behaviors when bonded to primary teeth, with the exception of the one-step self-etching system; and self-etching systems can achieve bond strength values as good in enamel as in dentin of primary teeth.

Abstract: Abstract Objective: The purpose of this study was to evaluate the effect of different surface treatments on bond strength between In-Ceram Zirconia ceramic and Panavia Fluoro Cement. Background Data: Although several surface treatments have been used on In-Ceram Zirconia, no study has been conducted to investigate the effect of the Nd:YAG laser. Materials and Methods: Nine In-Ceram Zirconia blocks (10 x 10 x 6 mm) received three different surface treatments (n = 3 per group): group 1-Al(2)O(3) sandblasting + silane; group 2-Al(2)O(3) sandblasting + Rocatec Plus + silane; and group 3-Al(2)O(3) sandblasting + Nd:YAG laser + silane. Resin cement was applied and light-cured, followed by the application of composite resin. The blocks were sectioned to obtain square rods with a cross-sectional dimension of 1.0 mm(2) (n = 12 per group). Microtensile bond strength (muTBS) was recorded using a universal testing machine at a cross-head speed of 0.5 mm/min and expressed in megapascals (MPa). Results: All groups yielded statistically significantly different muTBS mean values: group 1 (11.81 +/- 3.12 MPa); group 2 (15.75 +/- 4.45 MPa); group 3 (18.70 +/- 5.14 MPa) (ANOVA and Tukey's test; alpha = 0.05). Conclusion: Nd:YAG laser irradiation is an effective surface treatment for bonding between In-Ceram Zirconia and Panavia Fluoro Cement.

Abstract: The aim of this study was to compare and evaluate strain distribution on dental implant, abutment, screw and crown virtual models in the posterior region. The analysis was performed by means of a 3D virtual model developed by the PRO-ENGINEER System (PRO-ENGINEER, PTC, Needham, MA, USA ) with an external butt joint (3i Implant Innovations, Palm Beach, Florida), square headed Gold Tite abutment retainer screw (3i Implant Innovations, Palm Beach, Florida), STA abutment (3i Implant Innovations, Palm Beach, Florida), metal infrastructure of Ag-Pd alloy and feldspatic ceramic. The standard load was 382N at 15 degree angle to the implant axis, applied at 6 mm from the implant center at different observation points on the implant-screw set. The data showed that on the implant virtual model, the highest strain concentration was found at the interface between the implant platform and the abutment, and in the middle point of the 1st screw thread internal diameter on the load application side.

Abstract: BACKGROUND: Many post systems are available to clinicians, yet no consensus exists about which one is better in restoring endodontically treated teeth. PURPOSE: This study evaluated the fracture strength of teeth with flared canals and restored with two fiber-reinforced resin systems (glass fiber: FRC Postec [Ivoclar Vivadent, Schaan, Liechtenstein]; quartz fiber: D.T. Light-Post [Bisco Dental Products, Schaumburg, IL, USA]), and one custom cast base metal (Ni-Cr) post and core system. METHODS: Thirty anterior teeth had their crowns removed below the cemento-enamel junction and were endodontically treated. The canals were prepared for post fixation, and the canal walls were flared using a taper diamond bur. The prepared roots were randomly divided into three groups according to the post system. All posts were cemented with an adhesive resin cement. For the fiber-reinforced resin posts, cores were built up using microhybrid composite. Metallic crowns were luted using zinc phosphate cement. Specimens were loaded at 45 degrees in a universal testing machine at a crosshead speed of 0.5 mm/min until failure. The mode of failure was classified as repairable or nonrepairable. RESULTS: Teeth restored with cast posts had fracture strength twice that of teeth restored with resin posts. Fiber-reinforced resin posts failed at a compressive force comparable to clinical conditions, but all failures were repairable. CONCLUSION: Fracture strength and mode of failure in anterior teeth with flared canals varied according to the type of post used to support a crown. CLINICAL SIGNIFICANCE: Under the conditions of this study, cast posts are preferable to restore endodontically treated teeth with flared canals and no ferrule.

Abstract: This study evaluated the fracture pattern of four composites for indirect dental restoration relating to three-point flexural strength, compressive strength and modulus of elasticity (Solidex, Artglass, belleGlass, and Targis). Ten specimens of each composite were tested in a universal testing machine at 0.5 mm/min crosshead speed for flexural strength and 1mm/min for compressive strength. Fracture pattern was classified as complete or partial fracture. Modulus of elasticity was calculated from flexural strength data. Composites polymerized under high temperatures (belleGlass and Targis) had higher flexural strength and elastic modulus values than composites polymerized by light (Artglass and Solidex). However, they failed earlier under compression because they were more rigid and showed partial fracture in the material bulk.

Abstract: OBJECTIVE: To evaluate the effect of the activation mode of adhesive cementation on push-out bond strength of fiber-reinforced resin posts to root canal dentin. METHOD AND MATERIALS: Forty mandibular premolars were endodontically treated and randomly divided into 4 equal groups. In groups G-1, G-2, and G-3, Single Bond (3M Espe) was applied and light polymerized for 20 seconds; in group G-4, Scotchbond Multi-Purpose Plus (3M Espe) was used as an autopolymerized adhesive. The dual-cure resin cement Rely X ARC (3M Espe) was light polymerized in G-2 and G-3 but not in G-1 and G-4. The translucent post Light-Post (Bisco) was used in G-3 and the opaque post Aestheti-Plus (Bisco) in the other groups. The roots were sectioned in 3 parts (cervical, middle, apical); each slice was submitted to the push-out test at a crosshead speed of 0.5 mm/min. Data were analyzed by analysis of variance and Tukey test (a = .05). RESULTS: Light polymerization of both the adhesive and resin cement in G-2 led to significantly higher bond strength than in G-1, where only the adhesive was light polymerized. No difference was found between G-2 (opaque post) and G-3 (translucent post). The autopolymerized adhesive showed the highest bond strength in all root regions. The middle and apical post/root regions had similar bond strength, but it was significantly lower than that in the cervical region (P <.001). CONCLUSION: Bond strength to root dentin varied as a function of the activation mode of post adhesive cementation and post/root regions.

Abstract: The purpose of this study was to evaluate and compare the mechanical behavior of five nanofilled composites with dentin and enamel shades trough diametral tensile strength and knoop microhardness. 4 Seasons (Ivoclar Vivadent), Esthet X improved (Dentsply), Filtek Supreme (3M), Grandio (Voco) and Palfique Estelite (Tokuyama Dental Corp.) were used in this research. Twenty samples (6 mm diameter and 3 mm thickness) of each material were used. Ten samples were submitted to knoop microhardness and the others to diametral tensile strength examinations. The results were submitted to ANOVA and Tukey statistical tests (a=0.05). There were significant differences between the tested groups (p<0.05). The diametral tensile strength ranged from 36.08 (4 Seansons dentin) to 49.24 (Grandio enamel). The knoop microhardness ranged from 54.45 (Esthet X improved enamel) to 123.90 (Grandio dentin). A great variability in the mechanical behavior of the nanofilled composites was observed. However it was not recorded with dentin and enamel shades with the exception of Grandio.

Abstract: OBJECTIVE: The purpose of this study was to investigate the influence of Nd:YAG on microtensile bond strength (microTBS) of different adhesive systems for human dentin. BACKGROUND DATA: Lasers have been widely used in dentistry. New adhesive systems with different chemical compositions are introduced every year, and it is important to investigate the bonding of new adhesive systems to dentin irradiated with laser. METHODS: The occlusal surfaces of third molars were removed to obtain flat dentin surfaces. The teeth were randomly divided into six groups. Each adhesive system was applied, according to manufacturers' instructions, to surface dentine with and without Nd:YAG laser irradiation (0.9 W, 15 Hz, 60 mJ per pulse). A block of composite resin was built over the adhesive layer. The specimens were sectioned to obtain 0.70 x 0.70 mm of transversal section. Twenty test specimens were selected for each group, and were then submitted to microTBS on a universal testing machine. RESULTS: According to Student's t-test, for Single Bond, there was no statistically significant difference without (49.32 MPa) and with (47.34 MPa) laser application (p = 0.60). For the Tyrian SPE/One Step Plus, microTBS value with laser (27.09 MPa) was statistically higher than without laser (19.13 MPa), as well as for Adper Prompt L-Pop (22.85 and 13.78 Mpa; p < or = 0.01). CONCLUSION: The application of Nd:YAG laser to dentin provided an increase in the bond strength values for the Tyrian SPE/One Step Plus and Adper Prompt L-Pop adhesive systems, but did not influence the bond strength values of the Single Bond adhesive system.

Abstract: OBJECTIVE: The aim of this study was to evaluate the effect of different surface treatments on bond strength between In-Ceram Alumina (VITA) and Panavia Fluoro Cement (Kuraray), and to verify the association between bond strength values and the percentage of remaining cement on the ceramic surface. BACKGROUND DATA: Although several conventional surface treatments have been used on aluminous ceramic, no study investigated the effect of the Nd:YAG laser. METHODS: Nine In-Ceram Alumina blocks (10 x 10 x 6 mm) received three surface treatments: group 1, Al(2)O(3) sandblasting + silane; group 2, Al(2)O(3) sandblasting + Rocatec Plus + silane; and group 3, Al(2)O(3) sandblasting + Nd:YAG Laser + silane. Resin cement was applied and light cured, followed by the application of composite. Blocks were sectioned to obtain sticks with a cross-sectional area of 1.0 mm(2). Microtensile bond strength (microTBS) was recorded in a universal testing machine at a crosshead speed of 0.5 mm/min. Scanning electron microscopy images of the fractured areas were used to calculate the amount of remaining cement on the ceramic substrate. RESULTS: All treatments yielded statistically different microTBS values (MPa): group 1, 14.38(A); group 2, 20.09(B); and group 3, 23.21(C) (ANOVAand Tukey's test, alpha = 0.05). Pearson's correlation coefficient for microTBS x percentage of remaining cement was r = 0.92 (p < 0.05). CONCLUSIONS: The Nd:YAG laser was the most effective surface treatment, followed by Rocatec and Al(2)O(3) sandblasting. A strong positive association was found between bond strength values and percentage of remaining cement.

Abstract: OBJECTIVE: This in vitro study evaluated the tensile bond strength of Single Bond adhesive system to indirect composite surfaces treated with Er:YAG laser, fluoridric acid, or air abrasion. BACKGROUND DATA: Application of adhesive techniques is well established in restorative dentistry, yet the influence of surface treatments on the bond strength of adhesive systems to indirect composite restorations prior to luting or repair procedures remains unclear. METHODS: Two hundred and ten samples made of three indirect composites (BelleGlass, Sculpture, and Targis) were divided into 21 groups (n = 10) and treated with (1) control (no treatment); (2) silane (RelyX 3M ceramic primer); (3) 10% fluoridric acid; (4) Er:YAG laser; (5) Er:YAG laser + 10% fluoridric acid; (6) air abrasion; and (7) air abrasion + 10% fluoridric acid. Afterwards, silane and Single Bond adhesive system were applied on each treated surface, and a direct composite resin (Z250) cone was built. The prepared specimens were submitted to tensile bond strength test and stereoscopy evaluation to determine the type of failure after rupture. RESULTS: Bond strength mean values were statistically different in function of indirect composite and surface treatment. BelleGlass treated with Er:YAG laser had the highest mean value (22.92 MPa), and Sculpture conditioned with fluoridric acid had the lowest mean (11.88 MPa). Stereoscopy showed a predominant cohesive failure in Targis resin and mixed type for Sculpture and BelleGlass. CONCLUSIONS: These results suggest that Single Bond tensile bond strength improves with Er:YAG laser as a surface treatment compared to fluoridric acid or air abrasion.

Abstract: OBJECTIVES: The purpose of this study was to evaluate, in vitro, the tensile bond strength of the Single Bond (3M) adhesive system placed over dentin surfaces treated with air turbine, Er:YAG laser without contact and in focused or air abrasion. SUMMARY BACKGROUND DATA: The use of dentin adhesives is a well-established clinical routine among the dentists. However, there have been few reports comparing the influence of the Er:YAG laser, air abrasion, and air turbine on the Single Bond tensile bond strength of adhesives systems to dentin fact that could influence which tools dentists select for use in cavity preparations. METHODS: Twenty-three extracted retained human molars were used in this study. The coronal portion was divided in two parts and fixed in acrylic resin; the occlusal surface was abraded to a 2-mm width with a mechanic lathe until the dentin surface was completely exposed. The dental portions were divided into three groups of 15 each and treated with Er:YAG laser, air abrasion, or air turbine. A 3 mm hole in the center of each tooth was marked off using contact paper. Single Bond (3M) adhesive system was applied after acid phosphoric at 35% application for 15 sec over dentin surfaces. A resin composite cone was built into the delimited area to accomplish the tensile bond strength test on the EMIC universal test machine. The specimens were then evaluated by stereoscopy to determine the type of failures into the dentin-adhesive-resin composite surface. RESULTS: The tensile test was performed using the universal testing machine EMIC DL-2000 at a cross-head speed of 0.5 mm/min. The average results were: air turbine (17.52 MPa), Er:YAG laser (16.65 MPa) and air abrasion (15.83 MPa). Statistical treatment by ANOVA and Tukey's test (p < 0.01) showed no significant differences between the groups tested. The tensile bond strength test to the dentin showed no significant difference among the three groups when the Single Bond was used after the 35% phosphoric-acid conditioning. The stereoscopy showed a predominant adhesive failure in all groups. CONCLUSION: These results suggest that Single Bond tensile bond strength is the same as dentin prepared by Er:YAG laser, air abrasion, or air turbine.