Scielo RSS <![CDATA[Brazilian Journal of Oral Sciences]]> vol. 15 num. 2 lang. pt <![CDATA[SciELO Logo]]> <![CDATA[<b>Comparison of the indentation strength and single-edge-v-notched beam methods for dental ceramic fracture toughness testing</b>]]> Aim: To study influence of the cooling rate after sintering a veneering porcelain (Vita VM9) on fracture toughness by indentation strength (IS) and single-edge-v-notched beam (SEVNB) methods. Methods: Vita VM9 bars were sintered according to the manufacturer's recommendation and cooled under three conditions: Slow (inside the furnace from sintering temperature to room temperature); Normal (inside the furnace from sintering temperature to 500 ºC and outside the furnace from 500 ºC to room temperature); and Fast (outside the furnace from sintering temperature to room temperature). Fracture toughness was measured by IS (n=10) and SEVNB (n=10) methods. Data were analyzed by two-way ANOVA (α=0.05). Results: The fracture toughness obtained from SEVNB (slow - 1.02±0.10; normal - 1.09±0.13; and fast - 1,02±0.18 MPa.m1/2 cooling techniques) was significantly lower than IS (slow - 1.19±0.13; normal - 1.17±0.07; and fast - 1.16±0.06 MPa. m1/2 cooling techniques). There was no significant influence of the cooling technique (p=0.012). Conclusion: The measurement technique influenced the fracture toughness values . IS method overestimated the fracture toughness values. Irrespective of the measuring method, cooling rate did not influence the Vita VM9 veneering porcelain fracture toughness. <![CDATA[<b>Effectiveness of a single-tuft toothbrush for control of newly formed dental biofilm</b>]]> Aim: To compare the effectiveness of a single-tuft toothbrush (STB) with conventional toothbrushes (CT) to control dental biofilm neoformation in the dentogingival area. Methods: For this cross-sectional prospective blind study, 20 periodontally healthy subjects were selected and randomly divided into 4 groups: STB; CT; CHX - chlorhexidine mouthwash (positive control) and PS - placebo mouthwash (negative control). The subjects were instructed to use only the assigned care method for 72 h with a 7-day washout period between experiments. The evaluated parameters were visible and disclosed plaque indices (PI and DPI), gingival bleeding index (GBI) at baseline (T-0) and at the end of each experimental period (T-72). Results: Data analysis demonstrated that at T-0 no difference was observed for any of the parameters (p&gt;0.05); after 72 h, CT, STB and CHX showed equivalent effectiveness at controlling biofilm. When the PI data were analyzed, between T-0 and T-72, STB was similar to CT and CHX (p<0.05), whereas for DPI, STB was significantly superior to the other methods. Except for PS, all methods yielded similar results for GBI (p<0.05). Conclusion:The tested STB was effective at controlling short-term dental biofilm neoformation on the dentogingival area. <![CDATA[<b>Prevalence of endodontic diseases: an epidemiological evaluation in a Brazilian subpopulation</b>]]> Aim: To determine the prevalence of pulp and periradicular diseases in a Brazilian subpopulation, correlating the prevalence with sex, age and most affected teeth. Methods: Data collected from medical records of patients treated at the Clinic of Specialization in Endodontics of the Federal University of Pernambuco between 2003 and 2010. The following variables were recorded for each patient: sex, age, affected teeth and diagnosed endodontic disease. Using Pearson's chi-square and Fisher's exact tests, the collected data analysis was set at a 5% significance level. Results: From all the treated teeth, 57% were diagnosed with pulp diseases, with the symptomatic irreversible pulpitis being the most prevalent (46.3%), while among the diagnosed periradicular diseases (43%), chronic apical periodontitis was the most prevalent (81%). Pulp diseases were detected in men and women in an unequal mode (p=0.008). Subjects under 40 years old had higher prevalence of pulp disease (p=0.286), and patients over 50 years were most affected by periradicular diseases (p=0.439). Maxillary incisors and mandibular first molars were the most affected teeth by endodontic diseases. Conclusion:In the evaluated subpopulation, the endodontic diseases were more prevalent in the maxillary incisive, affected indiscriminately individuals of different age groups and chronic apical periodontitis was the most prevalent diagnosed disease. <![CDATA[<b>Absenteeism study in a steel industry of São José dos Campos, SP, Brazil</b>]]> Aim: To identify the factors involved in absenteeism in a steel industry in the city of São Jose dos Campos, São Paulo, Brazil. Methods: A cross-sectional study was carried out after obtaining permission from Institutional Ethics Committee in a steel industry. Worker's detailed information regarding absenteeism was obtained from the Health Department files, from January 2005 to December 2008. Specifical data were: sex, function, certificate type (medical or dental), the working sector, according to the Large Groups (LG) of Brazilian Classification of Occupations - 2002, working periods, duration of absenteeism (lost days), the main causes of absenteeism (International Classification of Diseases ICD-10). Results: A total of 570 workers were recorded. The majority of workers were males (97%), with medical certificate (97%), LG-7 workers in the production of industrial goods and services (62.09%), and operators of industrial machinery (68.3%) and the working period was Shift 4 - Monday to Friday from 8 am to 12 am and 1 pm to 5 pm (44.43 %). The total duration of absenteeism was 3,187 days, the main causes of diseases being problemas in the musculoskeletal system and connective tissue (18.48%), respiratory diseases (17.11%), injuries, poisoning and other external causes (11.24%), and diseases of the digestive tract (11.24%). Conclusion:It was concluded that there was under-reporting of absenteeism due to dental causes (41 events) during the study period. More studies in this field are required. <![CDATA[<b>Diagnostic performance of fractal dimension and radiomorphometric indices from digital panoramic radiographs for screening low bone mineral density</b>]]> A number of panoramic radiographic measurements have been associated with osteoporotic alterations. However, little is known about the differences in sensitivity and specificity among these measurements for screening low bone mineral density (BMD). Aim: To correlate and compare precision, sensitivity and specificity of panoramic radiomorphometric indices and fractal dimension (FD) for screening low BMD (i.e. osteopenia and osteoporosis). Methods: Sixty-eight female patients (42.78±15.59 years) were included in this study. Body mass index (BMI), mandibular cortical index (MCI), mandibular cortical width (MCW), FD and connectivity (C) were assessed. Low BMD was diagnosed by peripheral dual-energy X-ray absorptiometry (p-DXA). Non-parametric correlations were assessed among all variables. In addition, sensitivity and specificity of MCI, MCW and FD were estimated for screening low BMD. Results: Significant correlation was found between FD and BMI (p=0.013; r=0.269). In addition, FD was the most sensitive method for screening low BMD (70.8%, p=0.001). FD and MCI presented a significant and relatively high sensitivity, whereas MCW presented a high specificity for screening low systemic BMD. Conclusion:Among the analyzed methods, FD and MCI offer a significant and relatively high sensitivity, whereas MCW offers a high specificity for screening low BMD. <![CDATA[<b>Signs and symptoms of temporomandibular disorder and patients' satisfaction before and after orthognathic surgery</b>]]> Aim: To evaluate signs and symptoms of temporomandibular joint disorder and satisfaction in patients before and after orthognathic surgery. Methods: The sample consisted of 15 patients aged between 19 and 47 years old, indicated for orthodontic-surgical treatment. All patients answered an anamnesis questionnaire based on Helkimo Anamnestic Index to evaluate subjective symptoms and underwent a clinical evaluation based on Helkimo Disfunction Index, applied at three time points: before (T0), three (T1) and six months (T2) after surgery. Statistical models used were χ2 test (Chi-square), Tukey test, confidence interval and analysis of variance (ANOVA). Results: Statistical analysis revealed no significant difference in the incidence of joint sounds, maximum mouth opening, deviation of mouth opening and pain in the TMJ region (p&gt;0.05). No patient presented worsening of the symptomatology. As regards muscular pain, there was a statistically significant improvement with time (p<0.05) and 86.7% of patients reported that they were satisfied with the obtained results. Conclusion: Improvement of TMD after orthognathic surgery may not be the result of correcting malocclusion and satisfaction with the results can be a factor of TMD improvement. <![CDATA[<b>Influence of curing protocols on water sorption and solubility of a self-adhesive resin-cement</b>]]> Aim: To evaluate the effect of different activation protocols on the polymerization of a self-adhesive dual cured resin-based cement. Methods: Thirty disc-shaped specimens were prepared with the resin cement RelyX U200 (3M ESPE) and divided according to three protocols: immediate light-activation for 40 s, delayed light-activation (10 min after manipulation, for 40 s) or self-curing without light-activation. The specimens were desiccated, kept in water at 37 °C for 7 days and desiccated again to calculate water sorption, solubility and mass variation. Data were analyzed by Shapiro-Wilk Test and Wilcoxon tests (α=0.05). Images after the specimens' final desiccation were also made. Results: The Wilcoxon test revealed a significant difference for sorption and mass variation (p<0.05) and the highest value was observed in self-curing or chemical activation group (CA), followed by delayed light-activation (DL) and immediate light-activation (IL). Besides the water sorption parameters, there were also microvoids on the discs from the delayed and no light-activation groups. Conclusion: The light-activation immediately after manipulation is recommended for the evaluated resin cement. <![CDATA[<b>Effect of referral for dental service on dental-service utilization by primary school children aged 8 to 11 years in Enugu, Nigeria</b>]]> Aim: To determine how one dental education session and referral of study participants aged 8-11 years would affect utilization of oral-health care services. Methods: This descriptive prospective study recruited 1,406 pupils aged 8-11 years from randomly selected primary schools in Enugu metropolis. All pupils received one oral-health education and referral letters for treatment. Data were collected on the pupils' socio-demographic profile, family structure, and history of oral-health care utilization in the 12 months preceding the study and within 12 months of receipt of referral letter. The effect of these factors as predictors of past and recent dental service utilization was determined using logistic regression. Results: Only 4.3% of the study participants had ever used oral-health services in the 12 months prior to the study. Within 12 months of issuing the referral letters, 9.0% of pupils used the oral-health services. Children from middle (AOR: 0.46; CI: 0.29-0.73; p=0.001) and low socioeconomic strata (AOR: 0.21; CI: 0.11-0.39; p<0.001) and those living with relatives/guardians (AOR: 0.08, CI: 0.01-0.56; p=0.01) were still less likely to have utilized oral-health services. Conclusion: Referral of children for oral-health care increased the number of children who utilized oral health care services. <![CDATA[<b>Influence of different surface treatments of fiberglass posts on the bond strength to dentin</b>]]> Aim: To assess the influence of different fiberglass post surface treatments on the bond strength (BS) to root dentin. Methods: Thirty bovine root canals were endodontically treated and filled with gutta-percha and AH Plus sealer. At 24 h after the endodontic filling, the post spaces were prepared with Gates-Glidden drills and #3 drills of the DC White Post system, maintaining a 4 mm apical seal. The roots were randomly divided into three groups: S (fiberglass posts treated with silane), SA (fiberglass posts treated with silane and a hydrophobic adhesive system) and SHA (fiberglass posts treated with silane, followed by drying with hot air). The posts were cemented with a self-adhesive cement (RelyX U200). The specimens were stored in distilled water at 37 °C for 24 h and subjected to the push-out test (0.5 mm/min). Data were statistically analyzed using one-way ANOVA and Tukey's test (α=0.05). Results: SA and SHA groups showed the highest BS mean values (11.29 and 10.85 MPa, respectively), while the S group presented the lowest BS mean value (7.21 MPa). S group was significantly different from SA and SAH groups. Conclusion: The surface treatment of fiberglass posts influenced BS values. <![CDATA[<b>Tooth whitening recovers the color of pre-stained composites</b>]]> Aim: To assess the effect of home-whitening on aged and stained composite. Methods: Fifteen disc-shaped specimens (10 mm diameter x 2 mm thick) of Filtek Z350XT, shade A2E were fabricated, polished and embedded in wax, leaving exposed the top surface. The specimens were allocated to three groups (n=5): A - the specimens remained dry; B - conditioning in distilled water and; C - conditioning in distilled water and coffee. They were next subjected to whitening with 10% carbamide peroxide (Whiteness Perfect) for 4 h daily for 1, 2 and 4 weeks. Shade was measured with a spectrophotometer Easyshade and expressed based on the CIE L*a*b* system (ΔE*). Surface roughness was measured with a roughness meter (Ra-μm). Data were analyzed with two-way ANOVA and Tukey's test (α=0.05). Results: Conditioning, grouping and the interaction between both, influenced the ΔE* (p<0.0001), which exceeded the 3.3 threshold for visible color change after conditioning of Group C in black coffee. Whitening for 1 week significantly reduced ΔE* in this group. There were no significant changes in surface roughness. Conclusion: Home-whitening did not alter significantly the color of the nanocomposite, except when it was previously stained. One-week whitening was sufficient to recover color change to an acceptable level. <![CDATA[<b>Parental age is related to the occurrence of cleft lip and palate in Brazilian populations</b>]]> Aim: To evaluate the association of environmental risk factors, particularly paternal and maternal age, with gender and type of oral cleft in newborn with nonsyndromic cleft lip with or without cleft palate (NSCL/P). Methods:This study included 1,346 children with NSCL/P of two Brazilian Services for treatment of craniofacial deformities. Parental ages were classified into the following groups: maternal age <35, 36-39, and ≥40 years; paternal age <39 and ≥40 years. The data was analyzed with chi-square test and multinomial logistic regression analysis. The odds ratios were estimated with a 95% confidence interval. Results: Of the 1,346 children included in this study, CLP was the type of NSCL/P with highest prevalence, followed by, respectively, CL and CP. There was a greater occurrence of NSCL/P in males compared to females (55.8% versus 44.2%). CLP was more common in men, while the CL and CP were more prevalent in women (p=0.000). No association between maternal age and clefts was observed (p=0.747). However, there was evidence of association between father's aged ≥40 years old and NSCL/P (p=0.031). When patients with CP were analyzed separately, no association between the father's age and the child's gender (p=0.728) was observed, i.e. the female gender prevails among patients with CP, regardless of the father's age. Conclusion: This study showed that there were differences in the distribution of the non-syndromic cleft lip and/or palate and the gender, and fathers aged ≥40 years old may have increased risk of oral cleft. Further studies involving different populations are needed for a better understanding of the effect of maternal and paternal ages as a risk factor for the occurrence of oral clefts. <![CDATA[<b>Socioeconomic level and the parents' perception of the impact of oral diseases on their children's quality of life</b>]]> Aim: To analyze how parents of different socioeconomic levels perceive the impact of oral diseases on their children's quality of life. Methods:All parents or guardians of students aged 11 to 14 years old, regularly enrolled in fundamental schooling at public schools of two towns in the northwestern region of the State of São Paulo, Brazil, were enrolled in the study. The questionnaire of "Socioeconomic Assessment Tool" was used to classify the families with regards to socioeconomic class and the "Parental-Caregiver Perceptions Questionnaire (P-CPQ)" was used to verify the parents' perception of the impact of oral diseases on their children's quality of life. Results: 172 (41.8%) individuals answered the survey. Among them, most belonged to the Upper Low Class (61%). 21.5% of the individuals answered that they considered their children's oral health "regular or bad" and 71.5% answered that their child's general well-being was not or was little affected by the condition of his/her teeth, lips, jaws or mouth. There was an association between the quality of life sub-scales, especially "oral symptoms", with all socioeconomic classes. Conclusion: There is a relationship between parents' socioeconomic class and the perception of the impact of oral disease on their children's quality of life. <![CDATA[<b>Influence of adhesive and thermal cycling on the bond strength of ceramic brackets to dental ceramic</b>]]> Aim: This in vitro study investigated the effect of the application of an adhesive, silane and thermal cycling (TC) on the shear bond strength (SBS) of ceramic brackets to feldspathic ceramic. Methods: 16 cylinders of feldspathic ceramic were etched with hydrofluoric acid and divided into four groups (n=4): G1 - silane, without TC; G2 - silane, with TC; G3 - adhesive, without TC; G4 - adhesive, with TC. One layer of silane was applied on the surface of cylinders in G1 and G2 e one layer of photo-activated adhesive Single Bond Universal was used in G3 and G4. Ceramic brackets were bonded using Transbond XT. The SBS data were subjected to two-way ANOVA and Tukey's post hoc test (α=0.05). The Adhesive Remnant Index (ARI) was evaluated at 40× magnification. Results: Silane was more effective than adhesive on the SBS of the brackets to ceramic (p<0.05). TC decreased significantly the SBS values compared with the groups without TC (p<0.05). The ARI results showed predominance of score 0. Conclusion: Groups with silane showed higher SBS than groups with adhesive. TC influence significantly on the bond strength. Regarding ARI, score 0 predominated in all groups. <![CDATA[<b>Incisor proclination and gingival recessions: is there a relationship?</b>]]> Aim: To test the hypothesis that there is no relationship between the amount of vestibular inclination of mandibular incisors and the appearance of gingival recession in this region. Methods: This study included 20 patients selected in accordance with the following inclusion criteria: 1. adult patients without gingival recession in the mandibular incisors before treatment (T0), 2. no previous orthodontic treatment, 3. treated without tooth extraction in the mandibular arch, 4. bonded mandibular splinting from one canine to another after the active stage of orthodontic treatment (T1), 5. no visible wear of the incisal edge of the mandibular incisors, 6. Pre- and post-treatment teleradiography and plaster casts, and plaster casts 3 years post-treatment (T2). Depending on the amount of inclination of the mandibular incisors after treatment, the sample was divided into two groups: Group 1- 10 individuals (IMPA T1-T0 ≤ 5˚) and Group 2- 10 individuals (IMPA T1-T0 > 5˚). The measurement of length of the clinical crown (LCC) of the four mandibular incisors, distance between the incisal edge and vestibular marginal gingiva were made in plaster casts at T0, T1 and T2. Results: In spite of Group 1 presenting a reduction in LCC at T2, there was no statistically significant difference in LCC in the 3 time intervals evaluated in the two groups. Conclusion: The null hypothesis was accepted. The variation in the amount of vestibular inclination of the mandibular incisors during orthodontic treatment and 3 years after conclusion of treatment did not promote the appearance of gingival recessions in this group of patients. <![CDATA[<b>Perception of dental care among children</b>]]> Children that come to dental offices with fear and anxiety usually tend to resist conditioning mechanisms. Aim: To evaluate children's perception of dental treatment and to identify the factors influencing this perception. Methods: For this study, we selected a random sample of 100 children of both genders aged 3 to 12, treated at the Department of Dentistry of a University (Group I) and at a Children's Hospital (Group II). A structured questionnaire about the child's perception about dental care was applied and the children were asked to draw a picture of this topic. Results: This positive perception was more accentuated in Group I (94%) and in children aged 3 to 5 years (100%), particularly in girls (78%). The main cause of fear was the use of needles (42.4%). Many children (24.2%) reported to prefer the noninvasive procedures. Conclusion: A positive perception of dental treatment was observed in most children. Therefore, dental pediatricians must be aware of the children's perception for establishing a better conditioning.