Cláudia Maria Coelho Alves

Effect of different polishing systems on the surface roughness of microhybrid composites

The use of composite resins in dentistry is well accepted for restoring anterior and posterior teeth. Many polishing protocols have been evaluated for their effect on the surface roughness of restorative materials. This study compared the effect of different polishing systems on the surface roughness of microhybrid composites. Thirty-six specimens were prepared for each composite [Charisma® (Heraeus Kulzer), Fill Magic® (Vigodent), TPH Spectrum® (Dentsply), Z100® (3M/ESPE) and Z250® (3M/ESPE)] and submitted to surface treatment with Enhance® and PoGo® (Dentsply) points, sequential Sof-Lex XT® aluminum oxide disks (3M/ESPE), and felt disks (TDV) combined with Excel® diamond polishing paste (TDV). Average surface roughness (Ra) was measured with a mechanical roughness tester. The data were analyzed by two-way ANOVA with repetition of the factorial design and the Tukey-Kramer test (p<0.01). The F-test result for treatments and resins was high (p<0.0001 for both), indicating that the effect of the treatment applied to the specimen surface and the effect of the type of resin on surface roughness was highly significant. Regarding the interaction between polishing system and type of resin used, a p value of 0.0002 was obtained, indicating a statistically significant difference. A Ra of 1.3663 was obtained for the Sof-Lex/TPH Spectrum interaction. In contrast, the Ra for the felt disk+paste/Z250 interactions was 0.1846. In conclusion, Sof-Lex polishing system produced a higher surface roughness on TPH Spectrum resin when compared to the other interactions.

Influence of human and bovine substrate on the microleakage of two adhesive systems

The aim of this study was to evaluate in vitro the marginal sealing of two adhesive systems and to analyze the influence of human and bovine substrates on marginal microleakage in enamel. Rectangular-shaped class V cavities (4 mm wide × 2 mm high × 2 mm deep) were made as follows: 8 cavities were prepared on the buccal and lingual surfaces of the human teeth with margins located on enamel and 16 cavities were prepared on the buccal surfaces of the bovine teeth. The cavities were randomly assigned to 4 groups of 8 cavities according to the adhesive system and substrate: G1 - Prime & Bond 2.1 (Dentsply)/human substrate; G2 - Adhese (Ivoclar/Vivadent)/human substrate; G3 - Prime & Bond 2.1 (Dentsply)/bovine substrate; G4 - Adhese (Ivoclar/Vivadent)/bovine substrate. The cavities were filled with microhybrid composite resin (Fillmagic) and after polishing/finishing procedures, the teeth were subjected to a thermocycling regimen of 500 cycles with 1-min immersions in water at 55° ±2°C and 5° ± 2°C. Next, the teeth were coated with two layers of nail polish to within 1 mm of the margin, submerged in a 50% silver nitrate solution for 2 h, rinsed thoroughly in running tap and immersed in developing solution for 8 h. The restorations were bisected resulting in 16 specimens. Microleakage was observed under a stereomicroscope at x25 and recorded using four-point (0-3) scoring system. The data were analyzed statistically by the Mann Whitney U-test at 5% significance level. Leakage was present in all specimens and there was statistically significant difference between the adhesive systems. Adhese self-etching system showed significantly more leakage in both substrates (human - p= 0.0001 and bovine - p= 0.0031). There was no statistically significant difference between human and bovine substrates for either of the adhesive systems based on different bonding mechanisms (Prime & Bond 2.1 - p= 0.6923 and Adhese - p= 0.6109). Neither of the adhesive systems was capable to completely prevent microleakage and the self-etching system was more susceptible to microleakage.

A protocol to identify non-classical risk factors for preterm births: the Brazilian Ribeirão Preto and São Luís prenatal cohort (BRISA)

BackgroundPreterm birth is the main cause of morbidity and mortality during the perinatal period. Classical risk factors are held responsible for only 1/3 of preterm births and no current intervention has produced an appreciable reduction of this event. It is necessary to explore new hypotheses and mechanisms of causality by using an integrated approach, collaboration among research groups and less fragmented theoretical-methodological approaches in order to detect new risk factors and to formulate more effective intervention strategies.MethodsThe study will be conducted on a convenience cohort of Brazilian pregnant women recruited at public and private prenatal health services. A total of 1500 pregnant women in São Luís, and 1500 in Ribeirão Preto, will be invited for an interview and for the collection of biological specimens from the 22nd to the 25th week of gestational age (GA). At the time of delivery they will be reinterviewed. GA will be determined using an algorithm based on two criteria: date of last menstruation (DLM) and obstetric ultrasound (OUS) performed at less than 20 weeks of GA. Illicit drug consumption during pregnancy will be determined using a self-applied questionnaire and the following instruments will be used: perceived stress scale, Beck anxiety scale, screening for depression of the Center of Epidemiological Studies (CES-D), experiences of racial discrimination, social network and social support scale of the Medical Outcomes Study and violence (Abuse Assessment Screening and violence questionnaire of the WHO). Bacterial vaginosis, urinary tract infection and periodontal disease will also be identified. Neuroendocrine, immunoinflammatory and medical intervention hypotheses will be tested. The occurrence of elective cesarean section in the absence of labor will be used as a marker of medical intervention.ConclusionPsychosocial, genetic and infectious mechanisms will be selected, since there are indications that they influence preterm birth (PTB). The studies will be conducted in two Brazilian cities with discrepant socioeconomic conditions. The expectation is to identify risk factors for PTB having a greater predictive power than classically studied factors. The final objective is to propose more effective interventions for the reduction of PTB, which, after being tested, might subsidize health policies.

The impact of post preparation on the residual dentin thickness of maxillary molars

STATEMENT OF PROBLEM The oval-shaped palatal roots of maxillary molars usually have smaller cross-sectional diameter in the buccolingual direction. However, the effect of parallel-sided post preparation on the remaining dentin thickness of root canal walls is unknown. PURPOSE The purpose of this study was to investigate, in vitro, the residual dentin thickness (RDT) of palatal roots in maxillary molars after various intracanal procedures for post placement, and to determine the risk of root canal perforation or weakening on different root canal walls at 2 levels, coronal and apical. MATERIAL AND METHODS Fifteen extracted first maxillary molars exhibiting radiographic mesiodistal root canal widths ranging from 3.8 to 4.2 mm, measured at 5 mm from the apex, were selected from a pool of teeth. The teeth were horizontally sectioned at 2 levels, coronal and apical, after being embedded in acrylic resin with the aid of a metal index, allowing identical repositioning of the sectioned parts throughout the study. Each sectioned surface was photographed with a digital camera coupled to a microscope. The palatal roots were subsequently prepared for post placement as follows: endodontic preparation up to file K50, Largo 3 and 4 drills, and ParaPost 4.5 and 5.0. Cross-sections were rephotographed after each step. Image J software was used to measure the RDT of each root wall at both levels, and data were further analyzed with a 3-way ANOVA/General Linear Model (GLM) for repeated measures. The post-hoc Tukeys range test was used to calculate differences in RDT among the 4 root walls at each root level (α=.05). RESULTS A significant difference was observed among the intracanal procedures (P<.001). At the apical level, RDT was significantly lower after ParaPost preparation than at the coronal level (P=.009). Buccal and palatal walls displayed significantly lower RDT than the mesial and distal walls at both levels (P=.004). CONCLUSIONS Intracanal preparation up to ParaPost 5.0 increased the risk of perforation or weakening of the buccal and palatal walls, especially at the apical level.

Association between osteoporosis and periodontal disease

PURPOSE to verify the association of osteoporosis with periodontal disease. METHODS the study has included 39 postmenopausal women divided in three groups according to bone mass categories, through evaluation of mineral bone density (MBD), measured by X-ray double emission absorbimetry in the lumbar area (L1-L4): ): normal bone; osteopenia and osteoporosis. In all the participants the Clinical Insertion Level (CIL) index has been determined at the research onset and after one year, by the same examiner. The periodontal situation data have been submitted to statistical analysis with the paired t-Student test. RESULTS the periodontal exam has shown that postmenopausal women in the osteopenia presented lower CIL at the initial periodontal clinical exam (2.1+/-1.1 mm), while the ones in the normal bone showed less teeth support tissue loss after one year (3.1+/-1.6 mm). The statistical analysis has shown that there was no significant difference for the periodontal situation in the normal bone, but there was significant statistical difference for the osteopenia and osteoporosis patients, when CIL values from both evaluation periods were compared. CONCLUSIONS it is concluded that postmenopausal osteoporosis may be a possible risk factor for periodontal disease.

Salivary IgA and periodontal treatment needs in diabetic patients

Salivary IgA can serve as a first line of defense against pathogens that colonize and invade mucosal surfaces and may be protective against periodontal disease. The aim of this study was to assess salivary immunoglobulin A levels in diabetic and non-diabetic patients with different periodontal treatment needs. The Periodontal Screening & Recording (PSR) system was used to evaluate the periodontal treatment needs of 41 diabetic and 42 non-diabetic patients. Unstimulated whole saliva was collected from each patient immediately before clinical examination and stored at -20 °C until analysis. Salivary immunoglobulin A (s-IgA) levels were determined using an enzyme-linked immunosorbent assay, and values were expressed as optical density. Diabetic and non-diabetic patients were compared using clinical and laboratory data. PSR data indicated that periodontal disease was more frequent and more severe in diabetic patients. A higher prevalence of codes 3 and 4 was observed in diabetics as compared with non-diabetics (odds ratio = 2, P < 0.05). Furthermore, non-diabetic patients had more healthy sextants (code 0) than did diabetic patients. Over half of diabetic patients (∼54%) presented with s-IgA levels that were lower than the normal range (optical density from 0.4 nm to 0.6 nm; P < 0.05). In addition, diabetic patients showed a higher variability in s-IgA levels as compared with non-diabetic patients. In conclusion, diabetic individuals had lower s-IgA levels, more-frequent and more-severe periodontal disease, and a greater need for periodontal treatment as compared with non-diabetic patients.

The effect of iron on Streptococcus mutans biofilm and on enamel demineralization

Iron (Fe) may have an anticaries effect by specific inhibition of glycosyltransferase (GTF) enzymes of Streptococcus mutans, but this hypothesis has not yet been clarified. In this study, S. mutans biofilms were formed on blocks of bovine dental enamel of a predetermined surface hardness (SH). These biofilms were exposed eight times/day to 10% sucrose, and two times/day they were subjected to one of the following treatments: G1, 0.9% NaCl as a negative control; G2, 0.12% chlorhexidine digluconate (CHX) as a positive antibacterial control; G3, 0.05% NaF (225 ppm F) as a positive anticaries control; G4, G5, and G6, ferrous sulfate (Fe2+) at concentrations of 1.0, 10.0, and 100.0 µg Fe/mL, respectively. The experiment was performed in triplicate and was repeated three times (n = 9). The pH of the culture medium was determined every 24 h as an indicator of the biofilms acidogenicity. The biofilm formed on each block was collected for determination of the viable bacteria and concentration of extracellular polysaccharides (EPS). Enamel SH was again determined and the percentage of SH loss (%SHL) was calculated as an indicator of demineralization. Iron treatment reduced the number of viable bacteria formed in the S. mutans biofilm (p = 0.04), in a dose-dependent manner, and also reduced the enamels %SHL (p = 0.005). At 100 µg/mL, Fe reduced enamel demineralization as effectively as CHX and NaF (p < 0.05), but it did not inhibit EPS production. In conclusion, the data suggest that the anticaries mechanism of action of Fe may not involve the oxidative inhibition of GTFs.

Avaliação da fluoretação da água do sistema de abastecimento público na Ilha de São Luís, Maranhão, Brasil

The aim of the present study was to evaluate the fluoride levels in public water supply in Sao Luis island, Maranhao State, Brazil, during the month of October of 2006. A stratification sampling was applied, considering the water treatment station (06) and the different districts (46). For fluoride analysis it was used a specific ion electrode. The fluoride concentration varied for 0.05 to 0.84 ppm. Only one water treatment station (Italuis) presented an ideal concentration of fluoride. It was concluded that the fluoride levels need adjustments, evidencing that it is essential an external control for monitoring of those levels in public water supply of Sao Luis.

Factors underlying the polarization of early childhood caries within a high-risk population

BackgroundEarly childhood caries (ECC) are particularly prevalent in disadvantaged populations, and socioeconomic factors are associated with the polarization of disease. A previous study showed that even within a homogenous low-income population disease is polarized, indicating that other factors apart from income may contribute to disease susceptibility.MethodsThis study used a hierarchical approach to identify factors associated with polarization of ECC in low-income subjects. This cross-sectional study was conducted retrospectively using a cohort of 244 children (aged 48–72 months) with family incomes not exceeding double the minimum wage (U.S.

DENSIDADE MINERAL ÓSSEA SISTÊMICA VS SITUAÇÃO CLÍNICA PERIODONTAL: ESTUDO TRANSVERSAL EM MULHERES NA PÓS-MENOPAUSA

8,208.00/year), living in neighborhoods on the outskirts of São Luís, Maranhão, Brazil. The sample was divided into three groups based on the Significant Caries (SiC) Index: no caries group, few caries group (mean 1.38 lesions), and a high caries group (mean 3.82 lesions). Hierarchical multinomial logistic regression analyses were performed based on a theoretical model.ResultsTwenty-eight (11.5%) of the 244 children presented with high caries. Age (p = 0.026; prevalence ratio (PR) = 1.10; 95% confidence interval (CI) 1.01–1.20) and frequency of sucrose consumption - p = 0.001; PR 4.65 (95% CI 1.83–11.84) were associated with increased risk of ECC.ConclusionsIn the high caries group, greater consumption of sucrose between main meals may explain why, in a group of children with homogenous social and health conditions, some had more caries than others.