Repositório RCAAP

This study focused on adhesive interface morphologic characterization, nanoleakage expression and microtensile bond strength of two resin cements (RelyX ARC and RelyX U100) bonded to human dentin treated with Chlorhexidine. Forty non-carious third molars were ground flat to expose superficial dentine. Composite blocks were luted to the exposed dentine with/without chlorhexidine pre-treatment. Four experimental groups (n=10) were obtained: ARC, U100, ARC/CHX and U100/CHX. Control groups, ARC and U100, were not treated with chlorhexidine. Experimental groups, ARC/CHX and U100/CHX, were pre-treated with chlorhexidine prior to the luting process. After storage in water for 24h, the bonded teeth were sectioned into 0.9 x 0.9 mm cross sectional area sticks. Eight random sticks from each tooth were submitted to microtensile bond test at a crosshead speed of 0.05 mm/min until failure. Two sticks were prepared for hybrid layer evaluation by SEM analysis. Two sticks were immersed in silver nitrate for 24h for nanoleakage evaluation. Nanoleakage samples were carbon coated and examined using backscattered electron mode. Bond strength data were analyzed with analysis of variance (ANOVA) followed by Tukey Test (p<0,05): ARC (42.72 ±4.3)A, ARC/CHX (39.19 ±9.62)A, U100 (12.98 ±3.43)B, U100/CHX (11.97 ±2.6)B. An increase in nanoleakage was observed in groups treated with chlorhexidine for both resin cements. No well- established hybrid layer was identified in the U100 groups. Even though the use of chlorhexidine did not interfere on the bond strength values within each cement, its use along with self-adhesive cements adversely affects the resin-dentin bond morphology which in turn might compromise the resin-dentin bond stability over time.

The purpose of this study was to evaluate the effect of the topography parameters and hydrophobicity of restorative material used to restore non-carious cervical lesions on the biofilm formation. Four restorative materials were investigated: conventional glass ionomer cement (KF, Ketac Fill Plus, 3M ESPE), resin-modified glass ionomer cement (VT, Vitremer, 3M ESPE), nanofilled resin-modified glass ionomer (KN, Ketac Nano, 3M ESPE) nanofilled resin composite (FZ, Filtek Z350 XT, 3M ESPE). Forty disk specimens were prepared from each material, dived in four groups. Five samples were used for topography parameters analysis using a 3D profilometry. The amplitude parameters (Sa and Sq), spatial parameter (Sds) and hybrid parameter (Ssc) were extracted in area using cut off of 0.25mm. Hydrophobicity was determined by the contact angle measurement of deionized water on the surface. Biofilm was evaluated after 24 hours formation with each disk after stained with 1% fluorescein using confocal laser-scanning microscopy (CLSM). Data were analyzed using one-way ANOVA and Tukey test (α=.05), Pearson correlation was used to compare topography parameters with biofilm formation. Significant differences were found related amplitude parameters (Sa and Sq, FZ=KN˂VT˂KF). KN presented the highest hydrophobicity. FZ and KN presented the lowest thickness and biovolume of biofilm when compared with VT and KF. All topography parameters were significantly correlated with biofilm formation. FZ and KN, material with nanoparticles presented better performance related topography parameters and biofilm formation.

The aim of this study was to retrospectively analyze the clinical outcome of a of a complete fixed mandibular prosthesis supported by three implants with tilted distal implants and to evaluate the patient satisfaction. Materials and methods: Fifteen patients (10 women and 5 men) were included in a retrospective investigation with a mean of 11.2 months. Periapical radiographs were digitized to measure bone loss. To assess patient satisfaction with the prosthesis was applied a questionnaire composed of 4 questions about mastication, satisfaction, retention and aesthetic of the prostheses through the use of a visual analog scale (VAS). To verify the interference of treatment on quality of life of patients was used the questionnaire OHIP14br. Descriptive statistics and Mann-Whitney Test were used. Results: The survival rate of the implants was 97.77% and prosthesis survival rate was 93.33%. It was observed 9 loosening of screw torque. No other complications were observed. 73.33% of the prosthesis was immediately loaded and 36.66% of distal implants received angled abutments. The bone loss ranged from 0 to 2.89 mm with median 0.50 mm. Straight implants had a higher bone loss than the tilted implants (p<0.001).Mean bone loss was 1.64 ± 0.77 mm for the straight implants and 0.37 ± 0.56 mm for tilted implants. All patients reported contentment with the aesthetic and retention of the prosthesis. The masticatory ability was considered adequate by 86.67% and 93.34% of interviewed patients reported satisfaction with prosthesis. The result of applying the OHIP-14Br showed that treatment resulted in a compromised of patients quality of life next zero. Conclusions: A complete fixed mandibular prosthesis supported by three implants with tilted distal implants may be an alternative for implant treatment to an edentulous patient.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Conselho Nacional de Desenvolvimento Científico e Tecnológico

The objective of this study was to evaluate the root surfaces modifications after the application of different chemicals agents, and their influence on the attachment of a fibrin network and fibroblasts. From 96 anterior mandibular human incisor teeth, extracted due to severe periodontal disease, were obtained 192 dentin blocks (3x3x1 mm) of buccal and lingual surface and randomly divided into 6 groups: Control- control group, which received no treatment; Root surface scaling and root planing (SRP) - root surface was scaling and root planning with Gracey curetes; Citric acid - SRP + 30% citric acid 5 min; EDTA (ethylenediaminetetraacetic acid) - SRP + 24% EDTA gel for 1 min; Tetracycline capsule - SRP + for 3 min with a solution obtained by dissolving one 500 mg capsule of tetracycline in 2 mL of saline solution; Tetracycline gel - SRP + 50 g/mL tetracycline gel for 1 min. After dentin treatment the specimens were analyzed using 4 methodologies: 1- the demineralization level and residues of the product (n = 9); 2- the adhesion of blood components after 20 min of surface treatment (n = 9); 3- the fibroblast attachment after 24h (n = 9), were analyzed by scanning electron microscopy (SEM); and 4- the cell metabolism after 4h (n = 5) the methyltetrazolium (MTT) assay was used. Citric acid, EDTA and Tetracycline gel removed completely smear layer and smear plug on root surface, resulted in adequate demineralization .Tetracycline capsule produced great tetracycline residues with several demineralization areas on root dentin surface. Tetracycline gel and EDTA groups had more fibroblast fixation than other experimental groups. The highest mean blood clot adhesion score was observed in roots treated with a tetracycline gel, whereas, the least score was observed in roots treated with tetracycline capsule. These results demonstrated that EDTA and Tetracycline gel surface demineralization removed the smear layer over dentin surface and promoted adhesion of a fibrin network and fibroblast cells attachment. The Tetracycline capsule demonstrated less effective performance in all parameters tested.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

A fine-needle aspiration (FNA) is a technique used in the diagnosis of salivary glands tumors (SGT) for decades in various institutions in different countries. The aim of this study was to evaluate the diagnostic performance of FNA in SGT in a referral university oncology center in Brazil and compare the results between the anatomical sites of major salivary glands. The retrospective period of analysis reviewed 32.502 cytopathology exams, which 1.793 of head and neck, and of these 183 from major salivary glands. Eighty-one exams of SGT contained subsequent histopathologic exams. Posteriorly, the conclusions cytological and histopathological from these exams were then compared statistically to estimate the ability of FNA in identifying neoplastic or malignant nature of the SGT. The results regarding the ability of FNA in identifying neoplastic nature in parotid tumors for sensitivity and accuracy was 100%, while for submandibular tumors was 92.8% and 93.3% respectively, and 100% for specificity. The ability of FNA in identify the malignant nature in parotid tumors the results was 93.3% for sensitivity, 90% specificity and 92.5% accuracy, and in the submandibular the values was 100% for all variables. There was a high frequency of nondiagnostic FNA, especially in identifying neoplastic nature in submandibular. FNA showed high values of diagnostic performance in identifying neoplastic lesions and malignant lesions for parotid and submandibular, supporting its usefulness in the diagnosis of SGT, and highlights, in special, the importance of consider the greater frequency of non-neoplastic lesions in submandibular gland and neoplastic lesions in parotid.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

In the past few years, frameworks for multiple implants have been sectioned and welded for a passive fit. However, the welding process itself may lead to misalignments. The objective of this study was to evaluate the stress generated on splinted implants by three different designs of Ti (Ti-6Al-4V) prefabricated frameworks welded with two different techniques. Three frameworks were welded with Laser or TIG (tungsten inert gas) to implants 3, 4 and 5, forming (G3L, G3T), (G4L, G4T), and (G5L, G5T), groups. Stress was measured by quantitative photoelastic analysis. Results: There was higher concentration of stress with TIG in groups G5T and G5L, and with Laser in groups G3T and G3L (p <0.05). The statistical analysis used the Fisher Anova test. In G4T and G4L groups, no significant difference was observed (p> 0.05). On the second analysis, the stress of the implants on each framework was analyzed on implants 1 and 5, since they are present on the three frameworks. No significant differences were observed in the analysis of implant 1 (p> 0.05). On implant 5 of the Laser group, G3L was significantly different, with higher values than those of G4L and G5L. On implant 5 of the TIG group, only G5T was significantly different, with higher values than those of G3T and G4T. The statistical analysis used the Fisher Anova test and Tukey-S-B test. Conclusion: results were better for TIG on frameworks with fewer implants, and for Laser on frameworks with more implants.

The aim of this study was to evaluate in vivo, using beagle dog model, the effect of incorporation of biossilicato (highly bioactive glass) on the process of osteogenesis through the bone-implant contact and evaluate in vitro using model cell culture, the influence of the incorporation of biossilicato the rough surface on titanium discs adhesion and cell viability. The implants used for the in vivo study (n = 32) were 10 mm long and 3.5 mm in diameter and having surface treated with double etching. Half of these implants (n = 16) received the incorporation of biossilicato on its surface roughened (Group AA + BIO), while the other half only with rough surfaces (n = 16) was used as control group (group AA). The in vitro assays used commercially pure titanium disks grade IV 8.0 mm diameter by 4.0 mm in height with the same characteristics of implants used in in vivo tests. The assessment from scanning electron microscopy revealed that about 25% of the implant surface was covered by highly bioactive glass so homogeneous. Surface double etching associated biossilicato (AA + BIO) also showed a lower contact angle (α10s = 5.3 ± 1.7 °) compared with the AA surface. The adhesion test used to verify the stability of highly bioactive glass particles embedded on both disks as implants, demonstrate adequate stability, with no disruption of the interface bond between the particle and the surface of titanium. The results of in vitro through cell culture, showed that the percentage of viable cells adhered to the roughened surface covered with biossilicato (AA + BIO) was significantly lower (p <0.001) than the group with surface - AA (P = 0.004). The cell viability test showed that there were no statistically significant differences between groups AA and AA + BIO in any of the periods analyzed. The histomorphological results suggest that the initial repair is not affected by surface AA + BIO compared with the surface only with double etching.

Removing filling material from root canal is directly related to endodontics retreatment success. This study aimed to assess efficiency in removing filling material from root canals by using manual and rotary techniques with stainless steel and nickel titanium ProTaper Retreatment system respectively, and extrusion of debris through the apical foramen. Thirty human lower incisors were instrumented and filled with gutta percha and sealer by using lateral condensation technique. The extrusion of debris was quantified by waxing the apex which allowed shelter debris. The samples were divided in two groups (n=15): Group I (Rotary) were filling removal was performed by ProTaper Retreatment system completed by ProTaper Universal files; Group II (Manual) were filling removal was performed by using Gates Glidden burs, Kerr and Hedstrem files associated to organic solvent Eucaliptol. Samples were scanned by micro tomography after filling and after filling removal to quantify remaining filling material in root canal and extruded debris in these two steps. Remaining filling material percentage was obtained by difference between the filling volume before and after filling removal. Statistical analyses were performed by Mann-Whitney test for remaining filling material in full root canal and by Wilcoxon test in each third (cervical, medium and apical). The significance level was established in 5%. Descriptive analyses were performed to extruded debris assessment. There was no difference between the techniques in the total remaining filling material in root canals (p = 0.689) and in the thirds (p>0.05). Cervical third showed the lowest values for remaining filling material when compared to medium (p=0.001) and apical (p=0) thirds. Seven samples showed extruded debris, five from Rotary Group (30%) and two from Manual Group (13%). According to the results it can be concluded that both techniques showed similar performance in filling material removal considering the whole root canal. Cervical third showed the lowest remaining filling material amount in the two groups. Samples in which extruded debris were observed were insufficient to show which technique produced the event in higher or lower proportion. Neither technique tested removed filling material from root canal completely.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Primary stability has been regarded as a key factor to assure uneventful osseointegration of dental implants. Such stability is often achieved by placing implants in undersized drilled bone. This study evaluated the effect of drilling dimensions in insertion torque and early implant integration in a beagle dog model. Six beagle dogs were acquired and subjected to bilateral surgeries in the radius 1 and 3 weeks prior to euthanization. During surgery, three implants of 4 mm in diameter by 10 mm length were placed in bone sites drilled to 3.2mm, 3.5mm and 3.8mm in diameter. The insertion torque value was recorded for all samples. Following sacrifice, the implants in bone were non decalcified processed and morphologically and morphometrically (bone-to-implant contact (BIC), and bone area fraction occupancy (BAFO) evaluated. Statistical analyses were performed by Kruskal-Wallis followed by Dunn s post hoc for multiple comparisons at 95% level of significance. The insertion torque values obtained were inversely proportional to the drilling dimension, where a significant difference was detected between the 3.2mm and 3.8mm groups (p=0.003). Despite a significant increase in BIC over time in vivo for all groups (p=0.007), no effect of drilling dimension was observed. Additionally no effect of drilling dimension and time was observed for the BAFO parameter (p=0.31). Initial healing pathways differed between implants placed in bone drilled to different dimensions. While different degrees of torque were observed due to drilling dimensions and these resulted in different healing patterns, no differences in histometrically evaluated parameters were observed.

The aim of this study was to test the hypothesis that photo-activation protocol and resin cement affect the mechanical properties and bond strength of fiber glass posts to root dentin at different depths. Hundred fifty six bovine teeth were selected, sectioned to 15 mm long and instrumented with Kerr files and drills Gattes-Gliden. After endodontic instrumentation roots were prepared with a length of 10 mm to receive fiberglass post Exact no. 3(Angelus). RelyXU100 (3M-ESPE), BisCem (Bisco), Panavia F 2.0 (Kuraray) and RelyX ARC (3MESPE) resin cements were used to cement fiber glass posts in association with one of the three photo-activation protocols: light-curing immediate, 3 minutes and 5 minutes after to cement Exacto Fiber Post (Angelus). The root canal were stored at 37 ° C for 24 hours, after that time were carried tests push- out and hardness test In each group 10 posted root were used for push-out test obtaining 2 slices for each region for each root region cervical, middle and apical. For indentation test, the other 3 roots per group were sectioned longitudinally through the post included in cold resin inlay and polished. This samples were used by determinate modulus of elasticity (E) and Vicker s (VHN) hardness with load progressive of 0 to 500 mN in 20 seconds. E and VHN were determinate of the cement layer were assessed for each root depth. Resin cements RelyXU100 and BisCem showed significantly higher bond strengths than RelyX ARC and Panavia F. The delayed photo-activation protocol increased bond strengths for all resin cements evaluated. Bond strengths decreased significantly from coronal to apical root canal regions.Multiple linear regression determined that the bond streng this associated with the protocol photo activation (p <0.001) and root region (p <0.001) for all cements with R2 ranging between 0.594 and 0.643. The mean values for E and VHN increased significantly with the delayed photo-activation protocol for resin cements RelyX U100 and BisCem and decreased from coronal to apical root thirds for all resin cements. For the E and VHN, the multiple linear regression showed a direct relationship with the protocol of photo activation (p <0.001) and an indirect relationship with the depth to the cements tested (p <0.001) with high coefficients of determination (R2 from 0.721 to 0.908), but the time factor was more important for self-adhesive resin cements The delayed photo-activation protocol increased the bond strength and mechanical properties of self-adhesive resin cements used to lute fiber posts. The root canal region is a critical factor for the bond strength and mechanical properties of dual-cure resin cements photo-activated using different protocols.