Abstract in English:The objective of this study was to evaluate the flexural strength (σf) and hardness (H) of direct and indirect composites, testing the hypotheses that direct resin composites produce higher σf and H values than indirect composites and that these properties are positively related. Ten bar-shaped specimens (25 mm x 2 mm x 2 mm) were fabricated for each direct [D250 - Filtek Z250 (3M-Espe) and D350 - Filtek Z350 (3M-Espe)] and indirect [ISin - Sinfony (3M-Espe) and IVM - VitaVM LC (Vita Zahnfabrik)] materials, according to the manufacturer's instructions and ISO4049 specifications. The σf was tested in three-point bending using a universal testing machine (EMIC DL 2000) at a crosshead speed of 0.5 mm/min (ISO4049). Knoop hardness (H) was measured on the specimens' fragments resultant from the σf test and calculated as H = 14.2P/l², where P is the applied load (0.1 kg; dwell time = 15 s) and l is the longest diagonal of the diamond shaped indent (ASTM E384). The data were statistically analyzed using Anova and Tukey tests (α = 0.05). The mean σf and standard deviation values (MPa) and statistical grouping were: D250 - 135.4 ± 17.6a; D350 - 123.7 ± 11.1b; ISin - 98.4 ± 6.4c; IVM - 73.1 ± 4.9d. The mean H and standard deviation values (kg/mm²) and statistical grouping were: D250 - 98.12 ± 1.8a; D350 - 86.5 ± 1.9b; ISin - 28.3 ± 0.9c; IVM - 30.8 ± 1.0c. The direct composite systems examined produce higher mean σf and H values than the indirect composites, and the mean values of these properties were positively correlated (r = 0.91), confirming the study hypotheses.
Abstract in English:This study evaluated the effect of sterilization method on the bond strength of caries-affected dentin before artificial caries development and after restoration. Twelve bovine incisors were sectioned perpendicularly to their long axes at 7 mm from the amelodentinal junction. They were painted with acid-resistant nail varnish, except on an exposed coronal dentin area. Four groups were formed (n = 3) in accordance with the sterilization method used, before artificial caries development and after complete restoration: NE - no sterilization (control group); G - gamma-rays before and after; A - steam autoclave before and after; AG - steam autoclave before and gamma-rays after. For artificial caries development, dentin sections were immersed in BHI broth with S. mutans. After the soft carious tissue was removed, dentin was restored with Scotchbond Multi-Purpose and Filtek Z250. Next, the samples were sterilized in accordance with the methods described above and microtensile testing was performed. The data were analyzed by the Mann-Whitney test (p < 0.05). The G (22.7 MPa) and AG groups (16.3 MPa) were not statistically different from the NE group (17.5 MPa). Nevertheless, there were statistical differences between groups A (6.3 MPa) and NE, A and G, A and AG, G and AG. The bond strength of caries-affected dentin was not influenced by gamma-ray sterilization irrespective of whether the sterilization was performed before or after restoration.
Abstract in English:The aim of this in vitro study was to compare the time required for removal of intraradicular cast posts cemented with zinc phosphate (ZF) or glass ionomer cement (GIC), using two Brazilian ultrasound devices (BUD). Seventy two human inferior premolars with single root canals were sectioned transversally at the cementoenamel junction. In each specimen, the root canal was endodontically treated, the post space was prepared to a depth of 9 mm and the canal was molded to obtain a post impression. After the casting procedures, the posts were randomly distributed into 2 groups (n = 36) according to the luting material used: G1 - ZF and G2 - GIC. The tooth and luted post set was then embedded in an acrylic resin block. The groups were then divided into 3 subgroups (n = 12) according to the ultrasound device used: A - Enac (Osada Electric, Japan), used as a control group; B - Profi II Ceramic (Dabi Atlante, Brazil) and C - Jet Sonic Satelec (Gnatus, Brazil). The posts were submitted to the vibration process with maximum power set on all surrounding surfaces. Time of application was recorded with a chronometer until complete post dislodgment, and the data were analyzed by the ANOVA test (p < 0.05). The averages required for post removal in G1 and G2 were respectively 41.42 and 92.03 seconds, with significant statistical difference (p = 0.001). No statistical difference was observed among the three ultrasound devices (p = 0.088), and the BUD presented a performance similar to that of the international gold standard device (Enac). Moreover, the type of luting agent had a greater influence on the time required for post removal than the origin of the ultrasonic unit.
Abstract in English:This prospective clinical study aimed to evaluate the benefits of the endoscope as an aid to root-end management, and to assess the treatment outcome during 2 years following surgery. Forty-three endodontic surgical procedures in 30 patients were performed with the aid of an endoscope and followed for a period of 2 years. Radiographic criteria and clinical evaluation were used to assess the outcome. All cases were evaluated in terms of healing and functionality. 91.1% and 90.7% of the teeth evaluated after 1 and 2 years, respectively, were classified as successful. We found no statistically significant differences for both healing and functionality between the 1- and 2-year evaluations. No difference related to tooth type or tooth location was found at the 2-year follow-up. Fisher's exact test was used to statistically assess the difference between successful and unsuccessful cases for each of the variables considered. The endoscope can be an aid for endodontic surgical procedures in terms of both periapical healing and functionality up to 2 years follow-up.
Abstract in English:This hospital-based, case-control study investigated the possible associations between family history of malformations, parental consanguinity, smoking and alcohol drinking and nonsyndromic orofacial cleft (OC, subdivided in 2 main groups: CL/P - cleft lip with or without cleft palate and CP - cleft palate alone). 274 cases were matched (age, sex and place of residence) to 548 controls. Odds ratios (OR) and 95% confidence intervals (95% CI) - adjusted for maternal age, schooling and smoking / alcohol use - were calculated by conditional logistic regression. The results demonstrated that the history of oral clefts either in the father's (CL/P: OR = 16.00, 5.64-69.23; CP: OR = 6.64, 1.48-33.75) or in the mother's family (CL/P: OR = 5.00, 2.31-10.99, CP: OR = 12.44, 1.33-294.87) was strongly associated with both types of clefts, but parental consanguinity was associated only with CL/P (OR = 3.8, 1.27-12.18). Prevalence of maternal smoking during the first trimester of pregnancy was higher among cases but the OR (1.13, 0.81-1.57) was not statistically significant. Maternal passive smoking (nonsmoking mothers) during pregnancy was associated with CL/P (1.39, 1.01-1.98) but not with CP. Maternal alcohol use during the 1st trimester increased odds for CL/P (OR = 2.08, 1.27-3.41) and CP (OR = 2.89, 1.25-8.30), and odds for OC tended to increase with dose. Neither smoking nor alcohol use by fathers increased risks for OC. This study provides further evidence of a possible role of maternal exposure to tobacco smoke and alcohol in the etiology of nonsyndromic oral clefts.
Abstract in English:The aim of this study was to investigate the prevalence of orofacial clefts in live newborns from 1998 to 2002 in Brazilian state capitals and correlate their occurrence with a number of relevant socioeconomic factors collected in the 2000 census. Data was obtained from the Public Health Hospital Information System (SIH-SUS), Information System of Live Hospital Births (SINASC) and Atlases of Human Development in Brazil. The results showed that the mean prevalence of orofacial clefts in Brazil was 0.36 per 1,000 live births. Using Pearson's correlation coefficient, the correlation between cleft rate and social factors was not statistically significant (p > 0.05). Our study suggests that there is no correlation between the municipal economic factors and the prevalence of orofacial clefts, which is likely influenced by underrecording problems in the less developed municipalities.
Abstract in English:Traumatic neuroma, neurofibroma, neurilemmoma, palisaded encapsulated neuroma and malignant peripheral nerve sheath tumor (MPNST) are peripheral nerve sheath tumors and present neural origin. The goal of this study was to describe the epidemiological data of oral peripheral nerve sheath tumors in a sample of the Brazilian population. Biopsies requested from the Oral Pathology Service, School of Dentistry, Federal University of Minas Gerais (MG, Brazil), between 1966 and 2006 were evaluated. Lesions diagnosed as peripheral nerve sheath tumors were submitted to morphologic and to immunohistochemical analyses. All cases were immunopositive to the S-100 protein. Thirty-five oral peripheral nerve sheath tumors were found, representing 0.16% of all lesions archived in the Oral Pathology Service. Traumatic neuroma (15 cases) most frequently affected the mental foramen. Solitary neurofibroma (10 cases) was more frequently observed in the palate. Neurofibroma associated with neurofibromatosis type I (2 cases) was observed in the gingival and alveolar mucosa. Neurilemmoma (4 cases) was more commonly observed in the buccal mucosa. Malignant peripheral nerve sheath tumors (3 cases) occurred in the mandible, palate, and tongue. Palisaded encapsulated neuroma (1 case) occurred in the buccal mucosa. The data confirmed that oral peripheral nerve sheath tumors are uncommon in the oral region, with some lesions presenting a predilection for a specific gender or site. This study may be useful in clinical dentistry and oral pathology practice and may be used as baseline data regarding oral peripheral nerve sheath tumors in other populations.
Abstract in English:The purpose of this study was to evaluate the Shore A hardness and surface roughness of two silicones for maxillofacial prosthetic treatment, under the influence of chemical disinfection and storage. Twenty-eight specimens were obtained, half of which were made of Silastic MDX 4-4210 silicone and, the other half were made of Silastic 732 RTV silicone. The specimens were divided into four groups: Silastic 732 RTV and MDX 4-4210 with disinfection 3 times a week with Efferdent tablets and the same materials without disinfection. The hardness of the materials was analyzed with a Shore A Durometer. The surface roughness was established by a digital portable roughness tester, initially and 2 months after the confection of the specimens. A variance test was applied (2-way ANOVA), followed by Tukey test (the level of significance was set at 1%). The storage time factor statistically influenced (p < 0.01) the materials' properties of hardness and roughness. MDX 4-4210 (28.59 Shore A, 0.789 Ra) presented higher values than Silastic 732 RTV (18.08 Shore A, 0.656 Ra) for both properties. Regarding the disinfection period, there was no significant difference in any of the materials tested.
Abstract in English:This cross-sectional study aimed to determine the radiographic criteria used by final-year dental students when defining the need for restorative treatment for proximal caries, as well as investigating potentially associated factors in this therapeutic decision. A questionnaire with two schematic diagrams presenting five levels of proximal lesion penetration was administered to students attending the six private and three public dental schools in the state of Rio Grande do Sul, Southern Brazil. Absolute and relative frequencies were described and inferential statistics involving Chi-square and McNemar tests and simple logistic regression were carried out to assess variations in therapeutic decisions related to patient dentition (deciduous/permanent) and gender, age and dental school (public/private). Of the 346 dental students assessed, 28.6% (99/346) indicated restorative treatment for lesions restricted to the enamel in deciduous teeth and 38.2% (132/346) indicated the same for permanent teeth, revealing a statistically significant difference (p = 0.001). Student gender and age were not associated with the therapeutic decision; however, a significant difference between dental schools was found when comparing restorative criteria in deciduous (p < 0.001) and permanent molars (p < 0.001). The odds of restorative decision in permanent teeth when the caries lesion was restricted to the enamel was 72% higher for students graduating from private schools compared to public schools (Odds Ratio: 1.72; 95% Confidence Interval: 1.03-2.90). These data demonstrate a large variation between the therapeutic decisions regarding proximal caries reported by final-year dental students and suggest that deep reflection is needed on the part of faculty in order to provide an evidence-based education.
Abstract in English:The aim of this study was to evaluate the influence of diltiazem in combination with a sucrose-rich diet on gingival alterations in rats. One hundred and twenty male Holtzman rats were randomly assigned to 10 groups (n = 12), being 2 control groups treated with saline and 8 test groups treated with diltiazem in daily doses of 5, 25, 50 and 100 mg/kg during 40 or 60 days. Afterwards, the mandibles were removed for macroscopic, histologic and histometric analyses of the buccal gingiva of the mandibular right first molar. No macroscopic characteristic of gingival overgrowth was observed in any of the groups. The microscopic analysis showed characteristics of normality with inflammatory cells only adjacent to the crevicular epithelium in all groups for both periods. The histometric analysis showed significant differences only for the epithelial tissue area in the 40-day period (Kruskal-Wallis; P = 0.032). Comparing the periods, significant differences regarding the connective and epithelial tissue areas were observed only in the group treated with a 25 mg/kg dose (Mann-Whitney; P = 0.004 and P = 0.007, respectively). Oral administration of diltiazem in combination with a sucrose-rich diet did not induce gingival alterations in rats.
Abstract in English:The aim of this study was to evaluate the following acrylic resins: Clássico®, QC-20® and Lucitone®, recommended specifically for thermal polymerization, and Acron MC® and VIPI-WAVE®, made for polymerization by microwave energy. The resins were evaluated regarding their surface nanohardness and modulus of elasticity, while varying the polymerization time recommended by the manufacturer. They were also compared as to the presence of water absorbed by the samples. The technique used was nanoindentation, using the Nano Indenter XP®, MTS. According to an intra-group analysis, when using the polymerization time recommended by the manufacturer, a variation of 0.14 to 0.23 GPa for nanohardness and 2.61 to 3.73 GPa for modulus of elasticity was observed for the thermally polymerized resins. The variation for the resins made for polymerization by microwave energy was 0.15 to 0.22 GPa for nanohardness and 2.94 to 3.73 GPa for modulus of elasticity. The conclusion was that the Classico® resin presented higher nanohardness and higher modulus of elasticity values when compared to those of the same group, while Acron MC® presented the highest values for the same characteristics when compared to those of the same group. The water absorption evaluation showed that all the thermal polymerization resins, except for Lucitone®, presented significant nanohardness differences when submitted to dehydration or rehydration, while only Acron MC® presented no significant differences when submitted to a double polymerization time. Regarding the modulus of elasticity, it was observed that all the tested materials and products, except for Lucitone®, showed a significant increase in modulus of elasticity when submitted to a lack of hydration.
Abstract in English:The aim of this study was to assess the impact of oral status on the daily performances of civil servants from the Public Works and Waste Management Department of the city of Porto Alegre, located in Southern Brazil. A cross-sectional study was conducted on a representative sample composed of 276 civil servants with ages ranging from 35 to 44 years. The Oral Impacts on Daily Performances index developed was employed to measure impacts caused by oral clinical conditions. Oral examinations were performed after the interviews. Multinomial Logistic Regression Analysis was used. After adjusting for sex and educational level, the results showed that the subjects with high DMFT scores were 5.8 times (95% CI = 2.1-16.1) more likely to have high impacts on their everyday life than those with low DMFT scores. Subjects that presented some coronal caries were 4.3 times (95% CI = 1.9-9.8) more likely to have high impacts on their everyday life than those with no coronal caries. Dental status assessed through the DMFT index and coronal caries are important indicators of impacts on the everyday life of the studied population.
Abstract in English:Systemic sclerosis (SS) is an autoimmune disease with great repercussions on the hard and soft tissues of the orofacial region. The aim of this study was to investigate the relationship between mandibular osteolysis and mouth opening measurements, duration of disease and presence/absence of teeth. Twenty-five subjects were selected: 15 diagnosed with systemic sclerosis and 10 healthy controls. The SS patients were grouped according to the presence (group I) or absence (group II) of mandibular osteolysis. The healthy subjects served as the control group (III). All of them underwent panoramic radiography on Ortophos® equipment (Siemens) and were clinically examined, with mouth opening measurement. We observed that group I had a longer duration of the disease than group II (p = 0.003). Groups I and II presented the same mean mouth opening. There was an increasing correlation between mouth opening and duration of the disease in group I (p = 0.095), but this was not observed in group II (p = 0.596). There was no correlation between presence/absence of teeth and osteolysis (p > 0.999), or between presence/absence of teeth and side of osteolysis (p = 0.143). We could conclude that osteolysis seemed to develop in patients with a longer duration of the disease, but did not modify the degree of mouth opening in relation to patients without osteolysis, and the presence/absence of teeth was not significant. On the other hand, in the osteolysis cases, the longer the duration of the disease, the greater the opening of the mouth.
Abstract in English:This study analyzed the effects of the unilateral removal and dissection of the masseter muscle on the facial growth of young rats. A total of 30 one-month-old Wistar rats were used. Unilateral complete removal of the masseter muscle was performed in the removal group, and detachment followed by repositioning of the masseter muscle was performed in the dissection group, while only surgical access was performed in the sham-operated group. The animals were sacrificed at three months of age. Axial radiographic projections of the skulls and lateral projections of the hemimandibles were taken. Cephalometric evaluations were made and the values obtained were submitted to statistical analyses. In the removal group, there were contour alterations of the angular process, and a significant homolateral difference in the length of the maxilla and a significant bilateral difference in the height of the mandibular body and the length of the mandible were observed. Comparison among groups revealed significance only in the removal group. It was concluded that the experimental removal of the masseter muscle during the growing period in rats induced atrophic changes in the angular process, as well as asymmetry of the maxilla and shortening of the whole mandible.