Prolonged pacifier use during infancy and smoking initiation in adolescence: evidence from a historical cohort study.

AIM: To investigate the association between prolonged pacifier use during childhood and smoking in adolescence and early adulthood. METHODS: A historical cohort study including patients from a dental private office was designed. Dental records were used, which contained complete data about sucking habits from 314 children (2-10 years of age) who had attended a private dental office from 1988 to 1994 in Ibiá, Brazil. Then, we collected data about the smoking habits from 261 subjects who were successfully contacted again from 2004 to 2006. Our outcome variable was smoking, and subjects who had smoked more than 100 cigarettes during their lifetime were classified as smokers. Poisson regression analysis matched the association between oral habits and smoking. Incidence rate ratios (IRR) and 95% confidence intervals (95% CI) were calculated. The level of significance was set at 5%. RESULTS: We observed a statistically significant association between prolonged pacifier use (more than 24 months) and smoking (IRR = 4.48; 95% CI 2.32-8.65). Breastfeeding, in contrast, was a protective factor (IRR = 0.64; 95% CI 0.42-0.96). CONCLUSIONS: Prolonged pacifier use during childhood is positively associated with smoking initiation in adolescence and early adulthood.

Detection and quantification of periodontal pathogens in smokers and never-smokers with chronic periodontitis by real-time polymerase chain reaction.

BACKGROUND: The purpose of the present investigation is to compare the presence and number of periodontal pathogens in the subgingival microbiota of smokers versus never-smokers with chronic periodontitis and matched probing depths (PDs) using real-time polymerase chain reaction (RT-PCR). METHODS: Forty current smokers and 40 never-smokers, matched for age, sex, and mean PD of sampling site, were included in this investigation. A full-mouth periodontal examination was performed, and a pooled subgingival plaque sample was collected from the deepest site in each quadrant of each participant. To confirm smoking status, expired carbon monoxide (CO) concentrations were measured with a CO monitor. The presence and quantification of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola were determined using RT-PCR. RESULTS: Smokers had greater overall mean PD (P = 0.001) and attachment loss (P = 0.006) and fewer bleeding on probing sites (P = 0.001). An association was observed between smoking status and the presence of A. actinomycetemcomitans (P <0.001). The counts of A. actinomycetemcomitans (P <0.001), P. gingivalis (P = 0.042), and T. forsythia (P <0.001) were significantly higher in smokers. CONCLUSIONS: Smokers showed significantly greater amounts of P. gingivalis, A. actinomycetemcomitans, and T. forsythia than never-smokers. There was a significant association between smoking and the presence of A. actinomycetemcomitans.

A method to investigate the shrinkage stress developed by resin-composites bonded to a single flat surface.

OBJECTIVES: To purpose a method for predicting the shrinkage stress development in the adhesive layer of resin-composite cylinders that shrink bonded to a single flat surface, by measuring the deflection of a glass coverslip caused by the shrinkage of the bonded cylinders. The correlation between the volume of the bonded resin-composite and the stress-peak was also investigated. METHODS: A glass coverslip deflection caused by the shrinkage of a bonded resin-composite cylinder (diameter: d=8 mm, 4 mm, or 2 mm, height: h=4 mm, 2 mm, 1 mm, or 0.5 mm) was measured, and the same set-up was simulated by finite element analysis (3D-FEA). Stresses generated in the adhesive layer were plotted versus two geometric variables of the resin-composite cylinder (C-Factor and volume) to verify the existence of correlations between them and stresses. RESULTS: The FEA models were validated. A significant correlation (p<0.01, Pearson's test) between the stress-peak and the coverslip deflection when the resin-composites were grouped by diameter was found for diameters of 2 and 4 mm. The stress-peak of the whole set of data showed a logarithmic correlation with the bonded resin-composite volume (p<0.001, Pearson's test), but did not correlate with the C-Factor. SIGNIFICANCE: The described method should be considered for standardizing the stress generated by the shrinkage of resin-composite blocks bonded to a single flat surface.

Avaliação crítica de ensaios clínicos / Critical evaluation of clinical trials

A maioria dos cirurgiões-dentistas que não estão envolvidos com ensino e pesquisa não está acostumada a ler e interpretar artigos científicos, não se sentindo assim qualificados para avaliar criticamente esta literatura. Ensaio clínico aleatório (ECA) é o tipo de estudo que fornece o mais alto nível de evidência científica em relação à eficácia e segurança de intervenções. Quando executado de forma correta, possibilita a produção de resultados com menor possibilidade de vieses. São vários os critérios adotados para classificar os diversos tipos de ECAs, e os clínicos devem conhecer as normas que norteiam a condução deste tipo de estudo, para que possam avaliá-lo criticamente. Esta revisão tem como objetivo fornecer algumas informações sobre aspectos metodológicos de ECAs, que podem auxiliar na interpretação deste tipo de estudo.

Most dentists who are not involved with teaching and research are not used to read critically scientific papers, and do not fell qualified to evaluate this sort of literature. Randomized clinical trial (RCT) is the type of study that provides the highest level of scientific evidence on efficacy and safety of a specific intervention. When correctly conduced, it is able to produce results with less possibility of bias. There are several criteria used to classify different types of RCTs, and clinicians should know the guidelines about the conduction of this type of study. This review aims to provide some information on methodological aspects of RCTs, which may assist in interpreting this type of study.