Comparative evaluation of a fissure sealant and a flowable composite: A 36-month split-mouth, randomized clinical study.

OBJECTIVES: The purpose of the present clinical evaluation was to investigate the effect of a fissure sealant and a flowable composite at fissures of permanent molars in terms of retention and caries-incidence rates over a 36-month period. METHODS: Thirty-four patients, ages varied from 16 to 22 years, diagnosed with at least 2 non-cavitated pit-and-fissure caries in the first and second molars were involved in the study. A total of 220 sealants, were placed in 117 upper molars and 103 lower molars. Teeth were sealed with either a flowable resin composite (Tetric Evo Flow) or a sealant material (Helioseal F)(n = 110). Each restoration was evaluated in terms of retention and caries incidence at 6, 12, 24 and 36 months according to their location as well. Data were analyzed using Mann-Whitney U, Friedman and 1-way ANOVA tests at p < 0.05. RESULTS: Tetric Evo Flow showed total retention with 95.5%, 93.8%, 88.5% and 80.2% at 6, 12, 24 and 36-month follow-ups respectively, while Helioseal F had retention rates of 95.5%, 94.8%, 85.4% and 80.2% respectively. After 36-months, there were 6 subjects totally lost in Helioseal F group, whereas 7 of the Tetric Evo Flow sunjects were totally lost. Caries development was firstly detected at 12-month evaluation for both of the materials however, no significant differences were observed among materials in retention rates or caries incidence after 36-month follow-ups (p > 0.05). SIGNIFICANCE: Using the flowable composite found as effective as the fissure sealant after 36-months regarding retention and caries incidence rates.

Effect of finishing and polishing systems on the surface roughness and color change of composite resins.

BACKGROUND: This study is to examine the surface roughness and color changes occurring on composite resins following the application of different finishing and polishing systems. MATERIAL AND METHODS: In our study, a total of 200 samples were prepared from composites resin (6×2 mm) containing supra-nano, submicron hybrid, nanohybrid, nano-ceramic and microhybrid filler. They were polished with diamond, aluminum oxide, silicon carbide finishing and polishing systems. The initial color values of composite samples were measured with a spectrophotometer and surface roughness values with a profilometer. After that, samples were immersed of coffee solution and color measurements were repeated on the 1st and 7th day. The differences between surface roughness (Ra) and color change values (∆Eab) were evaluated using two-way analysis of variance (ANOVA) test (p<0.05). RESULTS: Finishing and polishing systems produced a statistically significant difference between the surface roughness values of nano-ceramic, submicron hybrid and microhybrid composite resin samples (p<0.05). Supra nano composite, which showed the lowest surface roughness after all finishing and polishing systems, showed the least color change after 7 days compared to other composite groups (p<0.05). The microhybrid composite with the highest surface roughness was the most color changing composite group (p<0.5). CONCLUSIONS: The spiral finishing and polishing system containing diamond particles was the system to provide the least color difference on all composite groups. However, color differences of all composite resin groups were found to exceed the perceptibility threshold (PT) and acceptability threshold (AT). Key words:Composite resin, color stability, surface roughness.

Influence of Bleaching Regimen and Time Elapsed on Microtensile Bond Strength of Resin Composite to Enamel.

OBJECTIVES: The aim of this study was to evaluate the effects of time elapsed since bleaching and different bleaching regimens on the microtensile bond strength of resin composite to enamel. METHODOLOGY: Forty flattened buccal enamel surfaces were divided into four groups: An unbleached (control) group and three bleaching groups. Control group specimens were not subjected to a bleaching regimen (Group 1), while those in the bleaching groups were bleached as follows: opalescence 10% (Group 2), whiteness perfect 16% (Group 3), and whiteness hydrogen peroxide 35% (Group 4). Thereafter, the bleached specimens were divided into three subgroups (n = 4 teeth each) for restoration according to predetermined posttreatment time intervals (immediately, 1 week, and 2 weeks). Bonded specimens were then sectioned and subjected to µTBS testing. The data were analyzed using Kruskal-Wallis and Mann-Whitney U-tests at α = 0.05. RESULTS: There was a significant difference in the µTBS of the resin composite to enamel in groups that were bonded immediately after bleaching and in the control group (P < 0.05). Compared to the control group, the µTBS in Groups 2, 3, and 4 decreased significantly 1-week postbleaching (P < 0.05). No significant difference in µTBS was observed between the bleached and unbleached groups 2 weeks after treatment (P > 0.05). CONCLUSIONS: Adhesive restorative procedures could not be performed immediately or after 1 week irrespective of the type or concentration of bleaching system used. Composite restorations on bleached enamel surfaces should be performed after an interval of at least 2 weeks.

Effects of different kinds of beers on the surface roughness of glazed and polished methacrylate and Silorane-based composites: a 1-month study.

BACKGROUND: The aim of this in vitro study was to evaluate the effect of different kind of beers on the surface roughness of glazed and polished methacrylate- and Silorane-based resin composites after different immersion periods. METHODS: Methacrylate-based resin composites (Tetric N-Ceram, Ceram-X) and a Silorane-based resin composite (Filtek Silorane) were tested in the study. A total of 126 specimens (n=42 for each composite) were fabricated using a cylindrical custom metal mould. Surface roughness measurement was performed using a profilometer at baseline and after a 1-week and 1-month immersion in different kind of beers or distilled water. The results were analysed using repeated measure ANOVA and Tukey's HSD test (α=0.05). RESULTS: Repeated measure ANOVA results revealed that immersion period was a significant factor in the surface roughness of the tested specimens (p<0.001). The lowest surface roughness values were obtained with the specimens' polished Optidisc+BisCover LV. Regardless of the polishing systems used, Tetric N-Ceram showed the statistically lowest surface roughness values (p<0.05), whereas Filtek Silorane showed the highest surface roughness (p<0.001). CONCLUSION: The surface roughness values of the tested resin composites were affected by the polishing procedure used, the exposure time in the solutions and the type of composite resin.

Prevalence of dental injuries and awareness regarding mouthguards among basketball players and coaches.

BACKGROUND: Dental injuries are frequently occurred by an impact to facial area among basketball players. In fact, mouthguards are able to absorb the power of impacts and protect teeth from excessive forces, it is crucial for players even at training to wear mouthguards. To determine the prevalence of dental injuries and investigate the awareness about the use of mouthguards among basketball players and coaches. METHODS: A 14-item questionnaire was designed and tested among licensed basketball players and coaches, all of whom were continuously exposed to the risk of dental injuries. The questions focused on the prevalence of dental injuries and attitudes and knowledge regarding the use of mouthguards among the players and coaches. Data were calculated using descriptive statistics and χ2 tests. RESULTS: A total of 53 coaches (18-69 years) and 351 players (12-38 years) participated. Of these, 124 players (35% of the total sample) had experienced oral injuries, including soft tissue lacerations (80.6%), fractures (17.7%) and avulsions (1.6%). Although the players had sustained dental injuries, 95% of them found mouthguards to be protective, and only 6.3% (N.=22) actually used a mouthguard. The rate of mouthguard use among players who had experienced an oral injury was significantly higher than that among players without any history of injury (P<0.05). Although 98% of the coaches believed that mouthguards could prevent dental injuries, only 47% of them suggested their use to their players. The most common reasons for not using a mouthguard were discomfort (37.7%) and difficulty in breathing (7.3%) or talking (6.4%). CONCLUSIONS: This study showed that the use of mouthguards among basketball players is very rare, with inadequate knowledge among the coaches. Consequently, more information is required through sports associations and dentists.

Effect of surface sealing on stain resistance of a nano-hybrid resin composite.

PURPOSE: This study investigated the influence of sealant application on stain resistance of a nanohybrid resin composite compared to the efficacy of a bonding agent used as a surface sealant on prolonging color stability of the resin composite. MATERIALS AND METHODS: 28 disc-shaped materials were prepared from a nano-hybrid resin composite Filtek Z550 and assigned to four groups: G1K: nonsealed; G2:Adper Single Bond; G3: Fortify ; G4: Biscover LV. After 24 h storage in distilled water at 37˚C, all specimens were subjected to thermocycling and immersed into coffee solution. Color measurements were performed using spectrophotometer (VITA Easyshade; Vident) according to CIEL*a*b* system. RESULTS: Color change values were significantly different among the groups in each evaluation period except for after thermocycling (p<0.05). For 7 days evaluation period, the difference between G3 and G4 group was statistically significant while G4 exhibited statistically significant differences (p<0.05 and p<0.0001 respectively) compared to control (G1) in 14 day whereas no significant difference was found between GI and GII in 28-day evaluation period. However, ΔE values of sealed specimens (GIII, GIV) differed significantly from non-sealed (GI) specimens after 28 days of immersion in coffee solution (p<0.05 and p<0.0001 respectively). CONCLUSION: It may be concluded that using a bonding agent as a surface sealant does not increase stain resistance of resin composites of the sealants evaluated. Biscover LV showed the highest efficacy to prolong color stability of the resin composite.

Clinical comparison of a flowable composite and fissure sealant: a 24-month split-mouth, randomized, and controlled study.

OBJECTIVES: The aim of this clinical study was to evaluate the retention rate and caries-prevention effect of a flowable composite compared to a conventional resin-based sealant in a young population over a 24-month period. METHODS: Thirty-four patients, ranging in age from 16 to 22 years, diagnosed with at least 2 non-cavitated pit-and-fissure caries in the first and second molars were selected for this randomized split-mouth design trial. A total of 220 sealants, were placed in 117 upper molars and 103 lower molars. The teeth were sealed with a flowable resin composite (Tetric Evo Flow) or a sealant material (Helioseal F). Each restoration was independently evaluated in terms of retention and the presence of caries at baseline and at 1, 6, 12, and 24 months. Data were analyzed using non-parametric Mann-Whitney U and Friedman 1-way ANOVA tests at p<0.05. RESULTS: Tetric Evo Flow showed complete retention with 100%, 95.5%, 93.8%, and 88.5% at 1, 6, 12, and 24-month evaluations, respectively, while Helioseal F retention rates were 98.1%, 95.5%, 94.8%, and 85.4%, respectively, for the same evaluation periods. At the 24-month recall, 4 (4.2%) total losses were observed in subjects treated with Tetric Evo Flow and 2 total losses (2.1%) for Helioseal F, respectively. No significant differences were observed between the materials in retention rates or caries incidence for each evaluation period (p>0.05). CONCLUSION: Placement of flowable composite as fissure sealants in the younger population seems to be as effective as conventional fluoride containing fissure sealants for the prevention of fissure caries. CLINICAL RELEVANCE: The use of a flowable composite as a fissure sealant material, in conjunction with a total-etch, single bottle adhesive, yielded better retention than did the conventional fluoride containing resin-based fissure sealant over a 24-month period in young patients.

Shear bond strength of a new self-adhering flowable composite resin for lithium disilicate-reinforced CAD/CAM ceramic material.

PURPOSE: The purpose of this study was to evaluate and compare the effects of different surface pretreatment techniques on the surface roughness and shear bond strength of a new self-adhering flowable composite resin for use with lithium disilicate-reinforced CAD/CAM ceramic material. MATERIALS AND METHODS: A total of one hundred thirty lithium disilicate CAD/CAM ceramic plates with dimensions of 6 mm × 4 mm and 3 mm thick were prepared. Specimens were then assigned into five groups (n=26) as follows: untreated control, coating with 30 µm silica oxide particles (Cojet™ Sand), 9.6% hydrofluoric acid etching, Er:YAG laser irradiation, and grinding with a high-speed fine diamond bur. A self-adhering flowable composite resin (Vertise Flow) was applied onto the pre-treated ceramic plates using the Ultradent shear bond Teflon mold system. Surface roughness was measured by atomic force microscopy. Shear bond strength test were performed using a universal testing machine at a crosshead speed of 1 mm/min. Surface roughness data were analyzed by one-way ANOVA and the Tukey HSD tests. Shear bond strength test values were analyzed by Kruskal-Wallis and Mann-Whitney U tests at α=.05. RESULTS: Hydrofluoric acid etching and grinding with high-speed fine diamond bur produced significantly higher surface roughness than the other pretreatment groups (P<.05). Hydrofluoric acid etching and silica coating yielded the highest shear bond strength values (P<.001). CONCLUSION: Self-adhering flowable composite resin used as repair composite resin exhibited very low bond strength irrespective of the surface pretreatments used.

The cytotoxic evaluation of mineral trioxide aggregate and bioaggregate in the subcutaneous connective tissue of rats

Objectives: The purpose of this study was to evaluate and compare the cytotoxic effects of ProRoot MTA and DiaRoot BA, a bioceramic nanoparticulate cement, on subcutaneous rat tissue. Study Design: Fifty Sprouge Dawley rats were used in this study. Polyethylene tubes filled with ProRoot MTA and DiaRoot BioAggregate, along with a control group of empty, were implanted into dorsal connective tissue of rats for 7, 15, 30, 60, and 90 days. After estimated time intervals the rats were sacrificed. The specimens were fixed, stained with hematoxylin and eosin, and then evaluated under a light microscope for inflammatory reactions and mineralization. Results: All groups evoked a severe to moderate chronic inflammatory reaction at 7 and 15 days, which decreased with time. Both the MTA and BioAggregate groups showed similar inflammatory reactions, except at 90 days when MTA showed statistically significant greater inflammation (p>0.05). The MTA group showed foreign body reaction at all times. Compared to BioAggregate, MTA showed significantly more foreign body reaction at 60 and 90 days (p<0.0001). After 30 days foreign body reaction of BioAggregate decreased significantly. Both MTA and BioAggregate groups showed similar necrosis at 7 and 15 days (p=0.094 and p=0.186 respectively). No necrosis was observed after 15 days. Similarly there was no fibrosis after 30 days for both MTA and BioAggregate groups (p>0.05). Conclusions: Since DiaRoot BioAggregate showed significantly better results than MTA, we can conclude that it is more biocompatible. However, further studies are required to confirm this result (AU)

Surface hardness evaluation of different composite resin materials: influence of sports and energy drinks immersion after a short-term period.

OBJECTIVES: This study evaluated the effect of sports and energy drinks on the surface hardness of different composite resin restorative materials over a 1-month period. MATERIAL AND METHODS: A total of 168 specimens: Compoglass F, Filtek Z250, Filtek Supreme, and Premise were prepared using a customized cylindrical metal mould and they were divided into six groups (N=42; n=7 per group). For the control groups, the specimens were stored in distilled water for 24 hours at 37°C and the water was renewed daily. For the experimental groups, the specimens were immersed in 5 mL of one of the following test solutions: Powerade, Gatorade, X-IR, Burn, and Red Bull, for two minutes daily for up to a 1-month test period and all the solutions were refreshed daily. Surface hardness was measured using a Vickers hardness measuring instrument at baseline, after 1-week and 1-month. Data were statistically analyzed using Multivariate repeated measure ANOVA and Bonferroni's multiple comparison tests (α=0.05). RESULTS: Multivariate repeated measures ANOVA revealed that there were statistically significant differences in the hardness of the restorative materials in different immersion times (p<0.001) in different solutions (p<0.001). The effect of different solutions on the surface hardness values of the restorative materials was tested using Bonferroni's multiple comparison tests, and it was observed that specimens stored in distilled water demonstrated statistically significant lower mean surface hardness reductions when compared to the specimens immersed in sports and energy drinks after a 1-month evaluation period (p<0.001). The compomer was the most affected by an acidic environment, whereas the composite resin materials were the least affected materials. CONCLUSIONS: The effect of sports and energy drinks on the surface hardness of a restorative material depends on the duration of exposure time, and the composition of the material.

The cytotoxic evaluation of mineral trioxide aggregate and bioaggregate in the subcutaneous connective tissue of rats.

OBJECTIVES: The purpose of this study was to evaluate and compare the cytotoxic effects of ProRoot MTA and DiaRoot BA, a bioceramic nanoparticulate cement, on subcutaneous rat tissue. STUDY DESIGN: Fifty Sprouge Dawley rats were used in this study. Polyethylene tubes filled with ProRoot MTA and DiaRoot BioAggregate, along with a control group of empty, were implanted into dorsal connective tissue of rats for 7, 15, 30, 60, and 90 days. After estimated time intervals the rats were sacrificed. The specimens were fixed, stained with hematoxylin and eosin, and then evaluated under a light microscope for inflammatory reactions and mineralization. RESULTS: All groups evoked a severe to moderate chronic inflammatory reaction at 7 and 15 days, which decreased with time. Both the MTA and BioAggregate groups showed similar inflammatory reactions, except at 90 days when MTA showed statistically significant greater inflammation (p>0.05). The MTA group showed foreign body reaction at all times. Compared to BioAggregate, MTA showed significantly more foreign body reaction at 60 and 90 days (p<0.0001). After 30 days foreign body reaction of BioAggregate decreased significantly. Both MTA and BioAggregate groups showed similar necrosis at 7 and 15 days (p=0.094 and p=0.186 respectively). No necrosis was observed after 15 days. Similarly there was no fibrosis after 30 days for both MTA and BioAggregate groups (p>0.05). CONCLUSIONS: Since DiaRoot BioAggregate showed significantly better results than MTA, we can conclude that it is more biocompatible. However, further studies are required to confirm this result.

Surface hardness evaluation of different composite resin materials: influence of sports and energy drinks immersion after a short-term period

Objectives: This study evaluated the effect of sports and energy drinks on the surface hardness of different composite resin restorative materials over a 1-month period. Material and Methods: A total of 168 specimens: Compoglass F, Filtek Z250, Filtek Supreme, and Premise were prepared using a customized cylindrical metal mould and they were divided into six groups (N=42; n=7 per group). For the control groups, the specimens were stored in distilled water for 24 hours at 37°C and the water was renewed daily. For the experimental groups, the specimens were immersed in 5 mL of one of the following test solutions: Powerade, Gatorade, X-IR, Burn, and Red Bull, for two minutes daily for up to a 1-month test period and all the solutions were refreshed daily. Surface hardness was measured using a Vickers hardness measuring instrument at baseline, after 1-week and 1-month. Data were statistically analyzed using Multivariate repeated measure ANOVA and Bonferroni's multiple comparison tests (α=0.05). Results: Multivariate repeated measures ANOVA revealed that there were statistically significant differences in the hardness of the restorative materials in different immersion times (p<0.001) in different solutions (p<0.001). The effect of different solutions on the surface hardness values of the restorative materials was tested using Bonferroni's multiple comparison tests, and it was observed that specimens stored in distilled water demonstrated statistically significant lower mean surface hardness reductions when compared to the specimens immersed in sports and energy drinks after a 1-month evaluation period (p<0.001). The compomer was the most affected by an acidic environment, whereas the composite resin materials were the least affected materials. Conclusions: The effect of sports and energy drinks on the surface hardness of a restorative material depends on the duration of exposure time, and the composition of the material.

The long-term effect of calcium hydroxide application on dentin fracture strength of endodontically treated teeth.

OBJECTIVE: The aim of this in vitro study was to evaluate the long-term effect of calcium hydroxide (CH) on the microtensile fracture strength (MTFS) of endodontically treated human teeth. MATERIALS AND METHODS: A total of 105 caries-free extracted human mandibular incisors were used. The teeth were divided into seven experimental groups of 15 teeth each. The root canals of all the teeth were rotary instrumented. The teeth in the control group were immediately obturated and tested for MTFS. The rest of the teeth were vertically compacted with CH and a sterile saline solution mixture and sealed with temporary filling. The teeth were stored in a moist environment for 30, 90, 180, 270, 360, and 540 days. On scheduled dates, the root canals were obturated and then the teeth were tested for MTFS with an Instron testing machine. The Kruscal-Wallis test and a post hoc Dunn's multiple comparison test was utilized. The statistical significance level was established at P < 0.05. RESULTS: The introduction of CH into the root canals seems to decrease the MTFS of teeth statistically significantly through the 180th, 270th, 360th, and 540th days, respectively, compared with the control group. The results clearly indicated that there are statistically significant differences between group 2 and group 7 (P < 0.001) and between group 3 and group 7 (P < 0.05). There were no statistically significant differences between the rest of the groups (P > 0.05). CONCLUSIONS: The results indicate that long-term CH treatments can significantly reduce the strength of the teeth, causing an increase in fracture risk.

Surface hardness of different restorative materials after long-term immersion in sports and energy drinks.

The purpose of this study was to evaluate the effect of sports and energy drinks on the surface hardness of different restorative materials over a 6-month period. Forty-two disk-shaped specimens were prepared for each of the four restorative materials tested: Compoglass F, Filtek Z250, Filtek Supreme, and Premise. Specimens were immersed for 2 min daily, up to 6 months, in six storage solutions (n=7 per material for each solution): distilled water, Powerade, Gatorade, X-IR, Burn, and Red Bull. Surface hardness was measured at baseline, after 1 week, 1 month, and 6 months. Data were analyzed statistically using repeated measures ANOVA followed by the Bonferroni test for multiple comparisons (α=0.05). Surface hardness of the restorative materials was significantly affected by both immersion solution and immersion period (p<0.001). All tested solutions induced significant reduction in surface hardness of the restorative materials over a 6-month immersion period.

Effects of sports drinks on color stability of nanofilled and microhybrid composites after long-term immersion.

OBJECTIVES: This study assessed the effects of three sports drinks on the color stability of two nanofilled and two microhybrid composite materials after 1-month and 6-month periods. MATERIALS AND METHODS: Twenty-eight disc-shaped specimens (diameter: 10mm and thickness: 2mm) each were made from four resin composites (Clearfil Majesty Posterior, Filtek Supreme, Clearfil APX, and Filtek Z250). All the specimens were stored in distilled water for 24h at 37°C. Then, the baseline color values (L*a*b*) of each specimen were measured using a spectrophotometer according to the CIEL*a*b* color scale. Seven randomly selected specimens from each composite material were then immersed in one of the three sports drinks (Powerade, Red Bull, and Burn) or distilled water (control) for 1 and 6 months. After each immersion, the color values of each specimen were remeasured, and the color change value (ΔE) was calculated. The data were evaluated using the Kruskal-Wallis and Mann-Whitney U-tests. RESULTS: The tested resin composites showed color changes over the 6-month evaluation periods. At 1 month, highest level of color changes was observed in the Clearfil APX specimens immersed in Burn (p<0.01). Clearfil Majesty Posterior showed less discoloration in all the composite materials tested after 6 months (p<0.001). Independent of the composite materials tested, Burn resulted in the highest level of discoloration after both immersion periods (p<0.01). CONCLUSION: All the test solutions used in the present study caused greater discoloration than the clinically acceptable level of threshold (ΔE<3.3) over the 6-month evaluation period except for Clearfil Majesty Posterior immersed in distilled water (2.91±0.28). The effect of each solution on the color stability of the composite materials depended on the type of solution, exposure time, and composition of the composite material. CLINICAL SIGNIFICANCE: The effect of a solution on color stability of composite materials depends on the type of solution, exposure time, and composition of the material. In clinical practice, patients should be aware of the staining effects and erosive potential of sports drinks if consumed a longer period of time.

The effect of one-step and multi-step polishing systems on the surface roughness and microhardness of novel resin composites.

OBJECTIVES: The objective of this in vitro study was to evaluate the surface roughness and micro-hardness of three novel resin composites containing nanoparticles after polishing with one-step and conventional multi-step polishing systems. METHODS: A total of 126 specimens (10 X 2 mm) were prepared in a metal mold using three nano-composites (Filtek Supreme XT, Ceram-X, and Grandio), 21 specimens of each resin composite for both tests (n=63 for each test). Following light curing, seven specimens from each group received no polishing treatment and served as controls for both tests. The specimens were randomly polished using PoGo and Sof-Lex systems for 30 seconds after being wet-ground with 1200-grit silicon carbide paper. The mean surface roughness of each polished specimen was determined with a profilometer. The microhardness was determined using a Vickers hardness measuring instrument with a 200-g load and 15 seconds dwell time. The data were analyzed using the Kruskal-Wallis test and the post hoc Dunn's multiple comparison tests at a significance level of .05. RESULTS: Among all materials, the smoothest surfaces were obtained under a matrix strip (control) (P<.05). There were no statistically significant differences among polishing systems in the resin composites for surface roughness (P>.05). The lowest hardness values for the three resin composites were obtained with a matrix strip, and there was a statistically significant difference compared with other polishing systems (P<.05) whereas no statistically significant differences were observed between the polishing systems (P>.05). CONCLUSION: The current one-step polishing system appears to be as effective as multi-step systems and may be preferable for polishing resin composite restorations.

An in vitro comparison of different adhesive strategies on the micropush-out bond strength of a glass fiber post

Objectives: To evaluate in vitro the push-out bond strengths of a glass fiber post adhesively luted with self-etchingresin based and self-adhesive luting cements, as well as modified application procedure of self-adhesive lutingcements in combination with single step self-etch adhesives.Materials and methods: Fifty single-rooted human maxillary central incisor teeth were endodontically treated anddivided into five groups (n=10). Glass fiber posts (RelyX Fiber Post) were cemented with the following materials:group 1: ED Primer II/Panavia F 2.0 (PAN); group 2: RelyX Unicem (RU); group 3: Maxcem (MC); group 4:Adper Prompt L-Pop (PLP)/RelyX Unicem; group 5: Optibond all-in-one (OB)/Maxcem. Bonded specimens werecut (1-mm-thick sections) and push-out tests were performed (crosshead-speed, 0.5 mm/min). Data were analyzedby one-way ANOVA followed by the Tukey-HSD test for post hoc comparisons at á = 0.05.Results: The highest bond strength was recorded for groups 4 and 2, with no statistically significant differencesamong them (p>0.05). Group 4 showed significantly higher bond strength than group 1 (p<0.001), group 3(p<0.0001) and group 5 (p<0.0001). Group 1 showed significantly higher bond strength than the group 3 (p<0.05).No statistically significant differences were observed among group 1 and group 2, group 1 and group 5, group 3and group 5. Group 3 showed significantly lower push-out bond strength than the all other luting strategies exceptfor the group 5.Conclusions: The push-out bond strength values of modified application procedure of self-adhesive luting cements(RU and MC) in combination with single step self-etch dentin adhesives (PLP and OB) did not improve the pushoutbond strength of fiber post when compared with those where the conventional use of self-adhesive cements (AU)

Effects of Er:YAG laser and air abrasion on the microleakage of a resin-based fissure sealant material.

OBJECTIVES: The aim of the present study was to evaluate the effects of different surface pre-treatment techniques on the microleakage of a resin-based fissure sealant material. METHODS: Thirty-five molars were divided into the following seven groups based on the surface pre-treatment technique used: (a) Erbium: Yttrium Aluminium Garnet (Er:YAG) laser (7 W); (b) Er:YAG laser (7 W)+acid etching (with 37% phosphoric acid); (c) Er:YAG laser (5.5 W); (d) Er:YAG laser (5.5 W)+acid etching; (e) air abrasion+acid etching; (f) air abrasion; and (g) conventional acid etching. The sealant was placed according to the manufacturers' instructions and light-cured for 20 sec. The sealed teeth were thermocycled for 10,000 cycles (5°-55°C), then immersed in 5% methylene blue for 24 h and sectioned mesiodistally. Each section was analyzed and photographed using a light microscope. Microleakage was assessed quantitatively by the degree of dye penetration and also qualitatively, scored on a three-point rating scale. Data were analyzed by one-way analysis of variance (ANOVA) and the Kruskal-Wallis test. The level of significance was set at p < 0.05. RESULTS: Regardless of the fissure morphology and penetration depth, enamel surfaces conditioned with Er:YAG laser irradiation exhibited significantly higher microleakage than those conditioned with air abrasion followed by acid etching, and those conditioned with conventional acid etching (p < 0.05). Air abrasion followed by acid etching, as well as conventional acid etching, provided a sufficient seal, whereas laser irradiation alone or in combination with acid etching exhibited higher microleakage than did the other groups. CONCLUSIONS: Conventional acid etching remains the most effective and the simplest technique.

An in vitro comparison of different adhesive strategies on the micro push-out bond strength of a glass fiber post.

OBJECTIVES: To evaluate in vitro the push-out bond strengths of a glass fiber post adhesively luted with self-etching resin based and self-adhesive luting cements, as well as modified application procedure of self-adhesive luting cements in combination with single step self-etch adhesives. MATERIALS AND METHODS: Fifty single-rooted human maxillary central incisor teeth were endodontically treated and divided into five groups (n=10). Glass fiber posts (RelyX Fiber Post) were cemented with the following materials: group 1: ED Primer II/Panavia F 2.0 (PAN); group 2: RelyX Unicem (RU); group 3: Maxcem (MC); group 4: Adper Prompt L-Pop (PLP)/RelyX Unicem; group 5: Optibond all-in-one (OB)/Maxcem. Bonded specimens were cut (1-mm-thick sections) and push-out tests were performed (crosshead-speed, 0.5 mm/min). Data were analyzed by one-way ANOVA followed by the Tukey-HSD test for post hoc comparisons at a = 0.05. RESULTS: The highest bond strength was recorded for groups 4 and 2, with no statistically significant differences among them (p >0.05). Group 4 showed significantly higher bond strength than group 1 (p <0.001), group 3 (p <0.0001) and group 5 (p <0.0001). Group 1 showed significantly higher bond strength than the group 3 (p <0.05). No statistically significant differences were observed among group 1 and group 2, group 1 and group 5, group 3 and group 5. Group 3 showed significantly lower push-out bond strength than the all other luting strategies except for the group 5. CONCLUSIONS: The push-out bond strength values of modified application procedure of self-adhesive luting cements (RU and MC) in combination with single step self-etch dentin adhesives (PLP and OB) did not improve the push-out bond strength of fiber post when compared with those where the conventional use of self-adhesive cements.

Micro push-out bond strengths of 2 fiber post types luted using different adhesive strategies.

OBJECTIVE: The objective of this study was to evaluate the push-out bond strengths of carbon and glass fiber posts adhesively luted with Panavia F 2.0 and RelyX Unicem luting cements, as well as a modified application procedure using RelyX Unicem cement in combination with a single-bottle total-etch adhesive in 3 segments of teeth. STUDY DESIGN: Sixty single-rooted human maxillary central incisors and canines were sectioned below the cementoenamel junction, and the roots were endodontically treated. The roots were divided into 2 fiber-post groups, and then divided into 3 subgroups of 10 specimens each to test different luting strategies. Bonded specimens were cut (1-mm-thick sections) and push-out tests were performed (crosshead-speed, 0.5 mm/min). Failure modes were evaluated using a stereomicroscope at original magnification ×40. RESULTS: Micro push-out bond strengths were significantly affected by the type of luting agent and the type of post (P < .05). In all root sections, the push-out bond strength values of glass fiber posts were significantly higher than that of carbon fiber posts (P < .05). Moreover, the highest push-out bond strengths were measured for Panavia F 2.0 and RelyX Unicem cements. These values were significantly higher than that of modified application procedure in the medium section for both glass- and carbon-fiber posts, and in the apical root sections only for glass-fiber post (P < .05). In each region, the modified application procedure showed the lowest bond strength values. Adhesive failure between dentin and cement was the most frequent type of failure. CONCLUSIONS: In all root segments, the glass fiber post provided significantly increased post retention compared with the carbon fiber post, regardless of the luting strategy used.