GAND classification and volumetric assessment of unilateral cleft lip and palate malformations using cone beam computed tomography.

The aim of this study was to propose a classification for unilateral cleft lip and palate (UCLP) malformations based on cone beam computed tomography (CBCT) images, as well as to estimate the amount of bone necessary for grafting, and to evaluate the relationship of this volume with scores obtained using the classification. CBCT images of 33 subjects with UCLP were evaluated according to gap, arch, nasal, and dental parameters (GAND classification). Additionally, these defects were segmented and the amount of graft needed for alveolar bone grafting was estimated. The reproducibility of GAND classification was analyzed by weighted kappa test. The association of volume assessment with the classification (gap and nasal parameters) was verified using analysis of variance, while the intra-observer agreement was analyzed using the intra-class correlation coefficient. The intra-observer reproducibility of the classification ranged from 0.29 to 0.92 and the inter-observer agreement ranged from 0.29 to 0.91. There were no statistically significant values when evaluating the association of the volume with the classification (P>0.05). The GAND classification is a novel system that allows the quick estimation of the extent and complexity of the cleft. It is not possible to estimate the amount of bone needed for alveolar bone grafting based on the classification; individualized surgical planning should be done for each patient specifically.

Clinical care in craniofacial microsomia: a review of current management recommendations and opportunities to advance research.

Craniofacial microsomia (CFM) is a complex condition associated with microtia, mandibular hypoplasia, and preauricular tags. It is the second most common congenital facial condition treated in many craniofacial centers and requires longitudinal multidisciplinary patient care. The purpose of this article is to summarize current recommendations for clinical management and discuss opportunities to advance clinical research in CFM.

EDTA treatment improves resin-dentin bonds' resistance to degradation.

The existence of unprotected collagen fibrils within the hybrid layer compromises the longevity of restorations. This phenomenon may be avoided if solutions other than strong acids are used for dentin demineralization. The hypothesis to be tested is that bond durability may be improved by EDTA demineralization. Dentin surfaces (human and bovine) were bonded: (1) after phosphoric-acid-etching, and after EDTA demineralization with (2) a total-etch adhesive and (3) a self-etching adhesive. After the teeth were sectioned into beams, half of the specimens were immersed in NaOCl, while the other half was immersed in water. Beams were tested to failure in tension. ANOVA and multiple-comparisons tests were used (P < 0.05). No differences in bond strength were found among the 3 bonding procedures, although bonds made to human molars were 43-61% higher than those to bovine incisors. After NaOCl immersion, only specimens subjected to EDTA demineralization maintained the initial bond strength. We conclude that the collagen network is better-preserved after EDTA demineralization.

Effect of thermal and mechanical load cycling on microtensile bond strength of a total-etch adhesive system.

To evaluate the effect of thermal and mechanical cycles on dentin bond strength to cervical margins of Class II restorations, 80 box-type Class II cavities were prepared on the surfaces of bovine incisors. The cavities were restored with Single Bond (3M-ESPE) and Z-250 composite (3M-ESPE) according to manufacturer's instructions. The incisors were divided into four groups: G1-Control, G2- Thermal cycling (2,000 cycles, 5 degrees C-55 degrees C), G3- Mechanical cycling (100,000 cycles; 50N) and G4- Thermal and mechanical cycling (2,000 cycles 5 degrees C-55 degrees C/100,000 cycles; 50N). The restorations were sectioned perpendicular to the cervical bonded interface into 0.7 +/- 0.2 mm-thick slabs. The slabs were further trimmed at the interface to 1.4 +/- 0.2 mm with a fine diamond bur to produce a cross-sectional surface area of 1 mm2. All specimens were then subjected to microtensile bond testing. Means and standard deviations were expressed in MPa. The bond strength data were analyzed by one-way ANOVA and Fisher's PLSD test (p<0.05). Fracture mode analysis was performed using SEM. Bond strengths were significantly lower when thermal and mechanical cycling were performed [G4-2.41 (8.57)] when compared to the other groups [G1-28.15 (14.03); G2-27.60 (10.14); G3-27.59 (8.67)]. No differences were observed among Groups 1, 2 and 3. Interfacial fracture of the control (G1) and thermocycling (G2) groups mainly occurred between the deepest portion of the adhesive resin and the top layer of the demineralized dentin (Interphase). Mixed failure was predominant and increased when mechanical cycling was applied (G3 and G4).

Effect of different filling materials in combination with intraradicular posts on the resistance to fracture of weakened roots.

The preservation and restoration of severely weakened pulpless teeth is a difficult and relatively unpredictable procedure. This study evaluated the resistance to fracture of experimentally weakened bovine roots internally reconstructed with different filling materials in combination with prefabricated post compared with restored roots that were relatively intact. The roots of 75 mandibular bovine incisors with similar bulks were selected. Of these, 60 were internally prepared to standardized dimensions, thereby simulating weakness. All roots were filled with different restorative materials. The specimens were submitted to the fracture resistance testing with the application of a tangential compressive loading at an angle of 135 degrees in relation to the long axes of the roots. Results indicated statistically significant differences in relation to the root conditions. Weakened roots were less resistant to fracture than were controls. The roots restored with the resin cement demonstrated the lowest fracture resistance values, but statistically significant differences were observed only when compared with those restored by the resin-modified glass-ionomer cement. Resin-modified glass-ionomer cement, polyacid-modified resin composite and resin composite behaved similarly without statistically significant differences among them. None of the materials evaluated were capable of achieving the fracture resistance recorded for unweakened controls.

Effect of different filling materials in combination with intraradicular posts on the resistance to fracture of weakened roots / Efeito dos diferentes materiais obturados em combinação com pinos intra-radiculares na resistência da fratura de raízes frágeis

The preservation and restoration of severely weakened pulpless teeth is a difficult and relatively unpredictable procedure. This study evaluated the resistance to fracture of experimentally weakened bovine roots internally reconstructed with different filling materials in combination with prefabricated post compared with restored roots that were relatively intact. The roots of 75 mandibular bovine incisors with similar bulks were selected. Of these, 60 were internally prepared to standardized dimensions, thereby simulating weakness. All roots were filled with different restorative materials. The specimens were submitted to the fracture resistance testing with the application of a tangential compressive loading at an angle of 135 in relation to the long axes of the roots. Results indicated statistically significant differences in relation to the root conditions. Weakened roots were less resistant to fracture than were controls. The roots restored with the resin cement demonstrated the lowest fracture resistance values, but statistically significant differences were observed only when compared with those restored by the resin-modified glass-ionomer cement. Resin-modified glass-ionomer cement, polyacid-modified resin composite and resin composite behaved similarly without statistically significant differences among them. None of the materials evaluated were capable of achieving the fracture resistance recorded for unweakened controls

Effect of collagen removal on microleakage of resin composite restorations.

This study evaluated the effects of collagen removal on the microleakage of two single-bottle adhesive systems. Forty human third molars were selected and each received two root preparations. The roots were randomly assigned for restoration using Prime & Bond 2.1 (Dentsply Ltda, Petrópolis, RJ 90915, Brazil) or Single Bond (3M Dental Products, St Paul, MN 55144, USA). One root in each tooth was treated with 36% H3PO4 for 15 seconds and the other received an additional treatment with 10% NaOCl for 60 seconds to remove the collagen layer before adhesive was applied. All preparations were restored with Z100 restorative resin (3M Dental Products). The specimens were submitted to 5,000 thermal cycles (5-55 degrees C) and stored in 37 degrees C distilled water for one year. The specimens were then coated with a varnish except for 1 mm of tooth structure surrounding the restoration and immersed in 2% buffered methylene blue for four hours. After rinsing, the restorations were sectioned and two independent observers scored the microleakage at the interface between the restorative material and the tooth using an optical microscope at x45 magnification. The scores were submitted to Fisher's Exact Test and the results showed that collagen removal significantly reduced microleakage for Prime & Bond 2.1 and had no effect on microleakage for Single Bond.

Clinical evaluation of glass-ionomer/resin-based hybrid materials used as pit and fissure sealants.

OBJECTIVE: The objective of the present study was to clinically evaluate the hybrid materials Vitremer and Dyract when used as pit and fissure sealants. METHOD AND MATERIALS: The materials were applied in pairs on the mandibular permanent first molars of 100 children, 7 to 8 years old. RESULTS: After 12 months of sealing, the clinical evaluation presented rates of 95.9% and 85.7% of complete retention for Dyract and Vitremer, respectively, indicating a statistically significant difference. The hybrid materials presented a statistically significant protective effect against caries compared with the control group at 6 and 12 months. CONCLUSION: The hybrid materials were able to control occlusal caries.

In vitro microleakage of composite restorations after nonvital bleaching.

OBJECTIVE: After bleaching treatment, esthetic restorations often need to be replaced due to color changes. Some papers have shown alterations in the bond of adhesive restorations to bleached teeth. The purpose of this study was to evaluate tooth and resin composite adhesion when submitted to nonvital dental bleaching. METHOD AND MATERIALS: One hundred and twenty bovine teeth were assigned to 3 groups (n = 40); paste of sodium perborate and water; 37% carbamide peroxide gel; and no bleaching (control). After 3 weeks of continuous bleaching treatment, standardized Class V cavities were prepared at the cementoenamel junction and restored with Single Bond adhesive system and Z100 resin composite. The samples were thermocycled 1,500 times (5 +/- 1/55 +/- 1 degrees C) with a 1-minute dwell time. Then, they were immersed in a 2% methylene blue solution (pH 7) for 4 hours, sectioned, and analyzed by stereomicroscopy. Microleakage analyses were done, using scores from 0 to 4, considering leakage on the incisal wall (enamel) and the cervical wall (dentin). Data were analyzed by Kruskal-Wallis and Mann-Whitney tests (alpha = 0.05). RESULTS: The results showed that sodium perborate and carbamide peroxide gel significantly increase the microleakage in Class V resin composite restorations to dentin but not to enamel margins. CONCLUSION: The risk of microleakage in dentin margins is increased soon after bleaching treatment.

Influence of cross-head speed on resin-dentin shear bond strength.

OBJECTIVE: To evaluate the influence of different cross-head speeds on shear bond strength test on the dentin surface. METHODS: One hundred and twenty extracted bovine incisors were embedded in polystyrene resin. The specimens were prepared by wet grinding with 320-, 400- and 600-grit Al2O3 paper exposing dentin. After the application of the adhesive system Single Bond (3M) to etched dentin, the composite resin Z-100 (3M) was applied and light cured. The specimens were randomly assigned to four groups (n=30). The shear bond strength tests were performed with an EMIC DL 500 universal testing machine at four different cross-head speeds: 0.50 (A); 0.75 (B); 1.00 (C); and 5.00 mm/min (D). RESULTS: The mean values of shear bond strength in MPa (SD) were: A, 11.78 (3.91); B, 11.82 (4.78); C, 16.32 (6.45); D, 15.46 (5.94). The data were analyzed with one-way ANOVA and Tukey's test (alpha=0.05). The results indicated that A=B

Microleakage of hydrophilic adhesive systems in Class V composite restorations.

PURPOSE: To investigate the microleakage of four hydrophilic adhesive systems: one "multiple-bottles" (Scotchbond Multi-Purpose Plus); two "one-bottle" (Single Bond, Stae); and one self-etching (Etch & Prime 3.0). MATERIALS AND METHODS: 120 bovine incisor teeth were divided into four groups (n = 30) and Class V cavities were prepared at the cemento-enamel junction. The cavities were restored with the adhesive systems and with Z100 composite. The teeth were thermocycled 1,000 times between 5+/-2 degrees C and 55+/-2 degrees C with a dwell time of 1 min, and then placed in a 2% methylene blue dye (pH 7.0) for 4 hrs, washed and sectioned vertically through the center of the restorations. The qualitative evaluation was made by three examiners who distributed pre-established scores (0-4) for each tooth using a stereomicroscope at x30 magnification. RESULTS: In enamel margins little microleakage was observed and the Kruskal-Wallis analysis did not show differences. In dentin margins the Kruskal-Wallis and multiple comparison analyses were applied: microleakage was significantly greater with Stae (median 3) and Scotchbond MP Plus (median 4). Single Bond (median 1) and Etch & Prime 3.0 (median 2) showed the best results in dentin margins, and the statistical analysis did not demonstrate differences in microleakage among these groups.

Physical properties of resinous cements: an in vitro study.

The flow rate capacity, hydrolytic degradation and radiopacity of three resin-based cements were tested and compared with zinc phosphate cement, when used in accordance with the manufacturer's instructions. There are no significant differences among the cements with regard to the flow rate. The zinc phosphate cement showed superior hydrolytic degradation compared with the other cements tested. The cements presented different radiopacities and the zinc phosphate cement was the most radiopaque. The results suggest that the development of resin-based materials associated with adhesive procedures can increase the effectiveness of indirect restorations.

Influence of collagen removal on shear bond strength of one-bottle adhesive systems in dentin.

PURPOSE: The aim of this study was to evaluate the influence of collagen removal on shear bond strength (SBS) of three hydrophilic one-bottle adhesive systems in dentin. MATERIALS AND METHODS: Test specimens were taken from one-hundred twenty bovine incisors. The specimens were debrided, polished with 320- to 600-grit Al2O3 paper, and randomly divided into 6 groups (n = 20): G1: acid/10% NaOCl + Bond 1 (B1H); G2: acid + Bond 1 applied according to manufacturer's instructions (B1); G3: acid/10% NaOCl + Optibond Solo (OSH); G4: acid + Optibond Solo used according to manufacturer's instructions (OS); G5: acid/10% NaOCl + Single Bond (SBH); G6: acid + Single Bond used according to manufacturer's instructions. In all groups, dentin was etched for 15 s, rinsed, and dried. In groups 1, 3, and 5, the 10% NaOCl was applied with a dwell time of 60 s, rinsed, and dried. In all groups, the adhesive systems were applied and light cured, and then a restorative composite resin (Z-100) was inserted in a teflon matrix and cured. The specimens were stored in humid conditions for 7 days at 37 degrees C. The SBS tests were performed in an EMIC universal testing machine with a crosshead speed of 0.5 mm/min. The mean bond strengths in MPa (+/- SD) were analyzed with two-way ANOVA and Tukey's test (alpha = 0.05). RESULTS: The application of NaOCl significantly increased the SBS values of all systems except Optibond Solo. The means (SD) for adhesive systems with 10% NaOCl treatment were: SBH = 14.28 (4.21)a; B1H = 14.39 (3.61)a; OSH = 10.35 (5.74)a; and values without 10% NaOCl were: SB = 10.35 (2.95)a; B1 = 9.38 (3.10)a; OS = 9.79 (3.48)b. Different superscripts indicate significant difference. CONCLUSION: The removal of collagen increased the strength of dentin bonding, depending on the adhesive system used.

Effect of collagen removal on shear bond strength of two single-bottle adhesive systems.

This study evaluated the effect of collagen removal on the shear bond strength for two single-bottle adhesive systems. The ultrastructure of the dentin after treatments and the dentin-resin interface were examined under SEM. The buccal and lingual surfaces of 80 extracted human third molars were ground to expose dentin. Teeth were randomly assigned to four groups and received the following treatments: Group 1(P&B 2.1), Prime & Bond 2.1 adhesive was applied according to the manufacturer's directions and Restorative Z100 composite resin was bonded to the dentin surface; Group 2 (P&B 2.1/NaOCl), the same procedures were followed as for Group 1 except that the surfaces were treated with 10% sodium hypochlorite (NaOCl) for one minute after acid conditioning; Group 3 (SB), Single Bond (3M) was applied according to the manufacturer's recommendations; Group 4 (SB/NaOCl), the same procedure was followed for Group 2, using Single Bond. The specimens were stored in humidity at 37 degrees C for 24 hours and tested in a shear mode at a crosshead speed of 0.5 mm/minute. The Kruskal-Wallis test and Multiple Comparisons were used for statistical analysis of the data. A one-minute exposure of dentin to 10% NaOCl following acid conditioning resulted in a significant increase of the dentin shear bond strength for Prime & Bond 2.1. The same treatment for Single Bond resulted in a significant reduction in bond strength. Groups 1 and 3 were not statistically different from each other. The presence of a collagen layer resulted in the formation of a hybrid layer and similar values of adhesion for both adhesive systems. The results may suggest that collagen removal improves the bond strength for this acetone-based adhesive system but several such systems would need to be investigated.

Shear bond strength of hydrophilic adhesive systems to enamel.

PURPOSE: To compare the enamel shear bond strength of four hydrophilic adhesive systems: one multiple-bottle (Scotchbond Multi-Purpose Plus), two one-bottle (Stae, Single Bond) and one self-etching (Etch & Prime). MATERIALS AND METHODS: 120 bovine incisor teeth were obtained, embedded in polyester resin, polished to 600 grit to form standardized enamel surfaces, and randomly assigned to four groups (n = 30). Each adhesive system was used on enamel according to the manufacturer's instructions, and resin-based composite (Z100) cylinders with 3 mm diameter and 5 mm height were bonded. Specimens were stored in humid environment for 1 week, and bond strength was determined using a universal testing machine, at a crosshead speed of 0.5 mm/minute. RESULTS: The mean shear bond strength values (MPa +/- SD) were: Single Bond: 24.28 +/- 5.27 (a); Scotchbond Multi-Purpose Plus: 21.18 +/- 4.35 (ab); Stae: 19.56 +/- 4.71 (b); Etch & Prime 3.0: 15.13 +/- 4.92 (c). ANOVA revealed significant difference in means (P < 0.01) and Tukey's test showed the statistical differences that are expressed by different letters for each group. It could be concluded that the self-etching adhesive system did not provide as good a bond to enamel surface, as did the one- and multiple-bottle systems.

Quantitative microleakage evaluation around amalgam restorations with different treatments on cavity walls.

The purpose of this in vitro study was to evaluate the dye penetration around amalgam restorations in dentin cavities by a quantitative test. Standardized circular cavities were prepared on the facial surface of 75 extracted human single-rooted teeth, and restored with dental amalgam. Different bonding/sealing treatments were used on the cavity walls before the restorations were placed. The specimens were thermo-cycled between 5 +/- 2 degrees C and 55 +/- 2 degrees C for 500 cycles with 1-minute dwell times, followed by immersion in a 2% methylene blue solution for 12 hours at 37 degrees C. The quantitative microleakage was evaluated by spectrophotometry and was expressed by microgram dye per tooth structure. The results showed that the use of bonded amalgam restorations was more effective in reducing microleakage.

Nonvital tooth bleaching: a 2-year case report.

A discolored, nonvital maxillary right central incisor was bleached with sodium perborate and water, used as a "walking" bleach. An excellent result was obtained, proving the efficiency of both the intracoronal bleaching technique and the materials employed. A clinical evaluation performed 2 years later revealed that the tooth was slightly stained but esthetically satisfactory.

Inhibition of demineralization in vitro around amalgam restorations.

OBJECTIVE: The purpose of this in vitro study was to evaluate some forms of preventing or avoiding demineralization within enamel cavity walls adjacent to amalgam restorations. METHODS AND MATERIALS: Third molar teeth were sectioned to obtain 72 specimens, divided into one control and five experimental groups: amalgam only; varnish plus amalgam; acidulated phosphate fluoride plus amalgam; adhesive amalgam; glass-ionomer cement plus amalgam; control (amalgam only, not subjected to a demineralization challenge). The experimental groups were subjected to PH and thermal cycling and then submitted to enamel hardness determinations. RESULTS: Significant differences between the treatment groups revealed that the bonded amalgam technique offered the best resistance to demineralization. The use of cavity varnish resulted in greater mineral loss than amalgam placed alone. CONCLUSION: The use of an adhesive system, glass-ionomer cement, or acidulated phosphate fluoride under amalgam restorations may interfere with development of secondary caries.

Secondary caries around amalgam restorations.

Secondary caries is one of the greatest causes for replacement of amalgam restorations. This study verified whether marginal defects in class I restorations could be a determining factor in the development of secondary caries. Fifty-five extracted premolars and molars whose occlusal surfaces were already restored with amalgam were selected. A macroscopic examination of these teeth was carried out to see whether there was a difference in the prevalence of caries beneath ditched and nonditched margins. To assess the presence of caries, a section was ground in each tooth so that the cut passed through a ditched margin and a better margin. This permitted assessment of the two types of margins that had been exposed to the same oral environment. Macroscopic examination revealed caries in 3.6% of the nonditched margins and caries in 20% of the ditched margins. Microscopic examination revealed caries in 47.06% of the nonditched margins and caries in 58.82% of the ditched margins. Statistical analysis supports the conclusion that the marginal defect itself is insufficient to determine the presence of secondary caries that surround the amalgam restoration on the occlusal surface.