Effect of Ceramic Conditioners on Surface Morphology, Roughness, Contact Angle, Adhesion, Microstructure, and Composition of CAD/CAM Ceramics.

The objective of this study was to investigate the effect of surface treatments in maximum profile valley depth (Rv), surface roughness (Sa), contact angle (Ca), shear bond strength (SBS) of a light-cured resin cement, microstructure, and composition of two CAD/CAM ceramics: Cerec Blocs/Dentsply Sirona (feldspathic - FEL) and Empress CAD/Ivoclar Vivadent (leucite-reinforced - LEU). The ceramic specimens were submitted to six surface treatments: (1) 5% hydrofluoric acid (HF) - 20 seconds; (2) 5% HF - 60 seconds; (3) 10% HF - 20 seconds; (4) 10% HF - 60 seconds; (5) self-etching ceramic primer (MEP) - 20 seconds; and (6) MEP - 60 seconds. Specimens treated with HF received silane application for 1 minute. Rv and Sa were evaluated in a confocal laser microscope (n=10) and the Ca in a goniometer (n=6). For the SBS test, two resin cement cylinders were bonded to each specimen, one tested after 24 hours in distilled water storage (37°C) and the other after one year (n=10). The microstructures and compositions were analyzed by scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS) (n=4). Rv, Sa, and Ca data were analyzed by two-way ANOVA, and the SBS data by three-way ANOVA, all followed by post-hoc Tukey's test (α=0.05). Results: Surface treatments with HF always produced higher Rv and Sa, and lower Ca than MEP 60s for both ceramics. After 1-year water storage, FEL ceramic treated with MEP for 60 seconds produced higher SBS values than HF treatments, whereas for LEU ceramic there were no differences among treatments. Application of MEP for 20 or 60 seconds produced no difference in Rv, Sa, Ca, and SBS for both ceramics. Surface treatments produced considerable differences in ceramic topography, but subtle ones in composition, for both ceramics. Conclusions: The results indicated that for FEL ceramic, MEP application for 60 seconds yielded higher SBS compared with HF etching, while for LEU ceramic the surface treatments did not influence the SBS results.

In Vitro Evaluation of Surface Properties and Wear Resistance of Conventional and Bulk-fill Resin-based Composites After Brushing With a Dentifrice.

OBJECTIVES: This study evaluated the effect of toothbrushing with a dentifrice on gloss, roughness profile, surface roughness, and wear of conventional and bulk-fill resin-based composites. METHODS AND MATERIALS: Gloss and surface roughness of resin-based composites (RBCs; Admira Fusion X-tra, Aura Bulk Fill, Filtek Bulk Fill Flowable, Filtek Bulk Fill Posterior Restorative, Filtek Supreme Ultra, Herculite Ultra, Mosaic Enamel, SDR flow+, Sonic Fill 2, Tetric EvoFlow Bulk Fill and Tetric EvoCeram Bulk Fill) were analyzed before and after brushing; the roughness profile and wear were also determined after toothbrushing. Representative three-dimensional images of the surface loss and images comparing the unbrushed and brushed surfaces were also compared. Analysis of variance and Tukey post hoc tests were applied (α=0.05) to the gloss, surface roughness, roughness profile, and surface loss data. Pearson's correlation test was used to determine the correlation between gloss and surface roughness, surface loss and percentage of gloss decrease after brushing, and surface loss and surface roughness after brushing. RESULTS: For all RBCs tested after 20,000 brushing cycles, the gloss was reduced and the surface roughness increased (p<0.05). However, the roughness profile and the amount of surface loss were dependent on the RBC brand. Admira Fusion X-tra, Aura, Tetric EvoCeram Bulk Fill, and Tetric EvoFlow Bulk Fill showed the deepest areas of wear (p<0.05). A significant negative correlation was found between gloss and surface roughness, and a weak correlation was found between the decrease in gloss and the extent of surface loss, and any increase in surface roughness and the surface loss. CONCLUSIONS: Toothbrushing with a dentifrice reduced the gloss, increased the surface roughness, and caused loss at the surface of all the RBCs tested. Considering all the properties tested, Mosaic Enamel exhibited excellent gloss retention and a low roughness profile and wear, while Admira Fusion X-tra exhibited the greatest decrease in gloss, the highest roughness profile, and the most wear.

Wear profile of canal wall surfaces and bond strength of endodontic sealers after in situ acid challenge.

AIM: To evaluate the wear of root wall surfaces, the bond strength of sealers to dentine and the demineralization around root filling materials after canals were exposed to acid challenge in situ. METHODOLOGY: Eighty-seven roots of mandibular incisors were selected. Thirty-two were used in the laboratory bond strength study (n = 8), and 55 in the in situ study (n = 11). Root canals were prepared biomechanically and then filled with gutta-percha and AH Plus, MTA Fillapex, Sealapex or Endofill. For 14 days, 11 participants used intra-oral devices with five sterilized roots (four experimental and one control - only canal prepared). Drops of sucrose were dripped onto roots allowing the accumulation of biofilm on canal surfaces. Roots were removed, sectioned and analysed for the following: bond strength of filling material using a push-out test and also wear profile and dentine demineralization using confocal microscopy. Bond strength (MPa) was evaluated by two-way anova and Tukey test (α = 0.05), and wear profile was assessed by Kruskal-Wallis and t-tests (α = 0.05). RESULTS: AH Plus had the highest bond strength values. Intermediate results were found in roots with MTA Fillapex and Endofill, whilst Sealapex had inferior results (P < 0.05). No significant differences were found amongst root thirds (P > 0.05). For wear profile, samples were associated with degradation of the filling materials after exposure to the oral environment (P < 0.05). Roots had signs of demineralization around the filling material when Sealapex and Endofill were used. CONCLUSIONS: Sealers were not able to prevent degradation of the adhesive interface and dentine. AH Plus and MTA Fillapex had superior bond strength to dentine and less intense demineralization around the root filling.

Bond durability in erbium:yttrium-aluminum-garnet laser-irradiated enamel.

This study sought to evaluate the influence of thermocycling and water storage on the microtensile bond strength of composite resin bonded to erbium:yttrium-aluminum-garnet (Er:YAG)-irradiated and bur-prepared enamel. Eighty bovine incisors were selected and sectioned. Specimens were ground to produce a flat enamel surface. Samples were randomly assigned according to cavity preparation device: (I) Er:YAG laser and (II) high-speed turbine, and were subsequently restored with composite resin. They were subdivided according to the duration of water storage (WS)/number of thermocycles (TCs): 24 h WS/no TCs; 7 days WS/500 TCs; 1 month WS/2,000 TCs; 6 months WS/12,000 TCs. The teeth were sectioned into 1.0 mm(2)-thick slabs and subjected to tensile stress in a universal testing machine. Data were submitted to two-way analysis of variance (ANOVA) and Tukey's test at a 0.05 significance level. The different periods of water storage and thermocycling did not influence the microtensile bond strength (microTBS) values in the Er:YAG laser-prepared groups. In bur-prepared enamel, the group submitted to 12,000 TCs/6 months' WS (IID) showed a significant decrease in bond strength values when compared to the group stored in water for 24 h and not submitted to thermocycling (IIA), but values were statistically similar to those obtained in all Er:YAG laser groups and in the bur- prepared groups degraded with 500 TCs/1 week WS (IIB) or 2,000 TCs/1 month WS (IIC). It may be concluded that adhesion of an etch-and-rinse adhesive to Er:YAG laser-irradiated enamel was not affected by the methods used to simulate degradation of the adhesive interface and was similar to adhesion in the bur-prepared groups in all periods of water storage and thermocycling.

SEM analysis of enamel surface treated by Er:YAG laser: influence of irradiation distance.

BACKGROUND: Depending on the distance of laser tip to dental surface a specific morphological pattern should be expected. However, there have been limited reports that correlate the Er:YAG irradiation distance with dental morphology. PURPOSE: To assess the influence of Er:YAG laser irradiation distance on enamel morphology, by means of scanning electron microscopy (SEM). METHODS: Sixty human third molars were employed to obtain discs (approximately =1 mm thick) that were randomly assigned to six groups (n=10). Five groups received Er:YAG laser irradiation (80 mJ/2 Hz) for 20 s, according to the irradiation distance: 11, 12, 14, 16, or 17 mm and the control group was treated with 37% phosphoric acid for 15 s. The laser-irradiated discs were bisected. One hemi-disc was separated for superficial analysis without subsequent acid etching, and the other one, received the phosphoric acid for 15 s. Samples were prepared for SEM. RESULTS: Laser irradiation at 11 and 12 mm provided an evident ablation of enamel, with evident fissures and some fused areas. At 14, 16 and 17 mm the superficial topography was flatter than in the other distances. The subsequent acid etching on the lased-surface partially removed the disorganized tissue. CONCLUSIONS: Er:YAG laser in defocused mode promoted slight morphological alterations and seems more suitable for enamel conditioning than focused irradiation. The application of phosphoric acid on lased-enamel surface, regardless of the irradiation distance, decreased the superficial irregularities.

Validity and reproducibility of different combinations of methods for occlusal caries detection: an in vitro comparison.

This study assessed the validity and reproducibility of different combinations of occlusal caries detection methods: visual examination (VE), laser fluorescence (LF) and radiographic examination (RE). Intra- and interexaminer reproducibilities were also assessed. Forty-seven extracted human molars were used and 121 sites, either suspected or not to be carious, were chosen. Occlusal surfaces were examined by 8 volunteers, assigned to three groups according to their level of knowledge and clinical experience on dental practice: group I, undergraduate students; group II, postgraduate students; group III, professors. Three combinations of methods were tested: A: VE+LF, B: VE+RE, C: VE+LF+RE. The examiners scored the sites using ranking scales and chose a final score based on their clinical experience. The gold standard was determined by histological examination of the sites. In general, LF and RE yielded poorer results than the combinations of methods. For combination A, group III showed the highest sensitivity, while group II showed the highest specificity. For combination B, group II showed moderate sensitivity whereas groups I and III exhibited low sensitivities; all groups of examiners reached substantial specificity. For combination C, all groups exhibited moderate sensitivity and substantial specificity. Interexaminer reproducibility ranged from fair to moderate for combinations A and C, while for combination B kappa values indicated moderate interexaminer reproducibility. It may be concluded that individual exams presented inferior performance than the conjunction of them. Combination C (VE+LF+RE) resulted in the best accuracy for all groups. The knowledge background of the examiners influenced their ability to detect caries lesions and affected interexaminer reproducibility.

Randomized, controlled trial comparing the retention of a flowable restorative system with a conventional resin sealant: one-year follow up.

UNLABELLED: This clinical trial evaluated the retention rate of a flowable restorative system (Bond 1 + Flow-It!) used as a pit-and-fissure sealant compared with a conventional filled resin sealant (Fluroshield) over a 1-year period. METHOD: Using a half-mouth design, 160 sealants (80 in primary and 80 in permanent teeth) were placed on sound first/second primary molars and first permanent molars of 40 children aged between 4 and 7 years. For both primary and permanent dentitions, half the teeth (n = 40) were sealed with Fluroshield and half (n = 40) with Bond 1 + Flow-It! Teeth were evaluated at baseline, 6- and 12-month intervals. RESULTS: For both materials, there was no total loss of sealants placed on either the primary or permanent molars over 1 year. From Fluroshield sealants placed on primary teeth, 33 were completely intact after 6 months and 31 after 1 year. From those placed on permanent molars, no loss of material was observed after 6 months, while partial loss was noticed on 5% of teeth at 1-year recall. For Flow-It! resin applied on primary molars, partial loss of material was observed in only 1 sealant after 6 months and in 2 sealants after 1 year. On permanent teeth, 100% retention rate was observed over a 1-year follow up. There was a statistically significant difference (P < 0.01) between the sealing materials on primary but not permanent teeth, and, overall, Flow-It! sealants presented a higher retention rate at both 6-month and 1-year evaluations. Significant differences (P < 0.01) between baseline and the other evaluation periods were also observed. CONCLUSION: It may be concluded that the flowable restorative system yielded optimal retention on both primary and permanent molars. Its retention rate was significantly higher than that of the conventional pit-and-fissure sealant on primary teeth.

Indirect aesthetic adhesive restoration with fibre-reinforced composite resin.

This paper describes the restoration of an endodontically treated upper first molar with a fibre-reinforced onlay indirect composite resin restoration. The clinical and radiographic examination confirmed that the tooth had suffered considerable loss of structure. Therefore, an indirect restoration was indicated. First, a core was built with resin-modified glass ionomer cement, followed by onlay preparation, mechanical/chemical gingival retraction and impression with addition-cured silicone. After the laboratory phase, the onlay was tried in, followed by adhesive bonding and occlusal adjustment. It can be concluded that fibre-reinforced aesthetic indirect composite resin restoration represented, in the present clinical case, an aesthetic and conservative treatment option. However, the use of fibres should be more extensively studied to verify the real improvement in physical and mechanical properties.

Clinical performance of a resin-modified glass-ionomer and two polyacid-modified resin composites in cervical lesions restorations: 1-year follow-up.

The aim of this study was to assess the clinical performance of a resin-modified glass-ionomer cement (Vitremer) and two polyacid-modified resin composites (F2000 and Freedom) over 1 year. Nineteen patients with at least three cervical lesions were selected, providing an initial sample size of 87 restorations (29 per material), being 78 to non-carious and nine to carious lesions. Restorations were evaluated at baseline, 6 months and 1 year after placement, using modified US Public Health Service criteria: colour match, marginal discoloration, caries, anatomical form, marginal integrity and surface texture. At baseline, restorations were considered as acceptable for all criteria. At 1-year recall, 21 restorations per material were re-examined. Freedom was rated Bravo or Charlie for all the examined criteria and Vitremer earned an Alfa rating solely for the criterion caries. On the contrary, F2000 showed the best overall results, although presenting significant alteration in colour match. Statistical analysis of data was performed using chi-square and Mc Nemar tests. As to the evaluated periods, significant difference was observed solely between baseline and 1-year recall. Freedom and Vitremer were statistically different (P < 0.01) as to anatomical form and surface texture. For F2000, significant difference (P < 0.05) was noticed as to colour match and anatomical form. After 1-year follow-up, F2000 showed the most acceptable results as to the analysed criteria.

Clinical evaluation of low-level laser therapy and fluoride varnish for treating cervical dentinal hypersensitivity.

The aim of this study was to evaluate in vivo the use of low-level galium-aluminium-arsenide (GaAlAs) (BDP 600) laser and sodium fluoride varnish (Duraphat) in the treatment of cervical dentine hypersensitivity. Twelve patients, with at least two sensitive teeth were selected. A total of 60 teeth were included in the trial. Prior to desensitizing treatment, dentine hypersensitivity was assessed by a thermal stimulus and patients' response to the examination was considered to be a control. The GaAlAs laser (15 mW, 4 J/cm2) was irradiated on contact mode and fluoride varnish was applied at cervical region. The efficiency of the treatments was assessed at three examination periods: immediately after first application, 15 and 30 days after the first application. The degree of sensitivity was determined following predefined criteria. Data were submitted to analysis and no statistically significant difference was observed between fluoride varnish and laser. Considering the treatments separately, there was no significant difference for the fluoride varnish at the three examination periods, and for laser therapy, significant difference (P < 0.05) was found solely between the values obtained before the treatment and 30 days after the first application. It may be concluded that both treatments may be effective in decreasing cervical dentinal hypersensitivity. Moreover, the low-level GaAlAs laser showed improved results for treating teeth with higher degree of sensitivity.

Assessing microleakage of different class V restorations after Er:YAG laser and bur preparation.

This study assessed in vitro marginal leakage of class V cavities prepared by turbine and Er:YAG laser and restored with different materials. Sixty cavities with enamel and dentine margins were prepared and assigned to six groups: I, II, III by turbine and IV, V, VI by Er:YAG laser. The following restorative systems were used: groups I and IV: Bond 1 + Alert; II and V: Fuji II LC; III and VI: SBMP + Dispersalloy. After finishing, specimens were thermocycled for 8 h and 45 min (500 cycles), isolated, immersed in a 0.2% Rhodamine B solution, sectioned oro-facially and analysed for leakage. The dye penetration means (%) were: occlusal I: 10.09 (+/- 21.28), II: 3.25 (+/- 10.27), III: 0, IV: 41.77 (+/- 42.48), V: 23.37 (+/- 33.79), VI: 12.66 (+/- 24.06); cervical I: 16.49 (+/- 26.67), II: 4.34 (+/- 13.71), III: 0, IV: 37.71 (+/- 30.47), V: 39.56 (+/- 43.35) and VI: 72.53 (+/- 37.79). The use of Er:YAG laser for cavity preparation yielded higher degree of marginal leakage, as compared with the use of conventional air-turbine. The enamel interface provided better marginal sealing, comparing with dentine/cementum margin. As to the cavity preparation device (i.e. laser or bur), the analysis of the results showed that bonded amalgam and Fuji II LC provided less infiltration, than Alert. On the other hand, for lased cavities, Alert provided the best results, similar to those of Fuji II LC and superior to those reached by bonded amalgam.