The Alcohol Harm Paradox in Periodontitis

Individuals of lower socioeconomic position (SEP) experience a greater rate of alcohol-related harms, yet they consume equal or lower amounts of alcohol than higher-SEP individuals. This phenomenon, called the "alcohol harm paradox" (AHP), gained attention recently, and different mechanisms have been proposed to explain it. Since both SEP and alcohol have been suggested to be associated with periodontitis risk, we conducted a secondary analysis using data from the National Health and Nutrition Examination Survey 2011 to 2012 and 2013 to 2014 cycles, aiming to examine 1) whether the association between alcohol consumption and periodontitis is modified by SEP and 2) the extent to which the effect of SEP inequalities on periodontitis is mediated by and/or interacts with alcohol consumption. We set educational attainment as the main SEP proxy and tested the poverty income ratio in subsequent sensitivity analyses. Effect measure modification analysis was employed, considering heavy drinking as exposure, and causal mediation analysis based on the potential outcome's framework decomposed the effect of SEP on periodontitis in proportions attributable to mediation and interaction. Models were fitted using binary logistic regression and adjusted for sex, ethnicity, age, body mass index, smoking status, diabetes, binge drinking, and regular preventive dental visits. The analytical sample comprised 4,057 participants. After adjusting for covariates, less educated heavy drinkers presented 175% (odds ratio, 2.75; 95% confidence interval [CI], 2.04-3.72) higher odds of periodontitis than their counterparts, and super-additive associations were found (relative excess risk due to interaction: 1.35; 95% CI, 0.49-2.20). Additionally, -69.5% (95% CI, -122.1% to -16.8%) of the effects of education on periodontitis were attributable to interaction with heavy drinking, consistent with the AHP. No contribution was found for the mechanism of mediation. Heavy drinking disproportionately impacts the occurrence of periodontitis in lower-SEP individuals. Lower-SEP individuals seem to experience differential effects of heavy drinking on periodontitis.

Effect of weight satisfaction on adolescent facial and dental satisfaction

PURPOSE

To investigate if facial and dental satisfaction is related to body fat percentage and body weight satisfaction.

METHODS

A self-administered questionnaire was applied to adolescents from a Private School in Southern Brazil containing sociodemographic (sex and age) and self-perception variables. Adolescents were asked about their perceptions concerning dental problems. Body fat percentage was collected using bioelectrical impedance analysis.

RESULTS

A total of 372 adolescents were examined. Most adolescents were satisfied with their dental (81.7%) and facial appearance (87.6%), while 39% of adolescents were satisfied with their body weight. Poisson regression model showed that adolescents who expressed satisfaction with their body weight (PR = 1.12, 95%CI 1.06-1.19) and were satisfied with their dental appearance (PR = 1.24, 95% CI 1.08-1.41) exhibited a positive association with facial satisfaction. Adolescents dissatisfied with dental color (PR = 0.88, 95%CI 0.80-0.97), those reporting dental pain (PR = 0.88, 95%CI 0.80-0.97), and individuals with obesity (PR = 0.91, 95%CI 0.83-0.99) demonstrated a decrease in facial satisfaction. Adolescents aged 16 to 19 years (PR = 1.08, 95% CI 1.01-1.15) and those satisfied with their facial appearance (PR = 1.20, 95%CI 1.01-1.43) exhibited a higher prevalence of dental satisfaction. Conversely, adolescents dissatisfied with dental color (PR = 0.74, 95% CI 0.66-0.82) and those with misaligned teeth (PR = 0.63, 95%CI 0.55-0.73) reported lower levels of dental satisfaction. Parametric g-formula analysis found that the association between body fat and facial satisfaction was mediated by body weight satisfaction (p = 0.001).

CONCLUSIONS

While dental satisfaction was not influenced by corporeal characteristics, facial satisfaction was influenced by dental and body weight satisfaction. Obese adolescents had low facial satisfaction.

Difficulties in the use of medications by elderly people followed up in a cohort study in Southern Brazil

OBJECTIVE

This study aimed to assess the need for help by elderly people to take their medications, the difficulties related to this activity, the frequency of forgotten doses, and factors associated.

METHODS

Cross-sectional study conducted with a cohort of elderly people (60 years and over - "COMO VAI?" [How do you do?] study), where the need for help to properly take medication and the difficulties faced in using them were evaluated. The Poisson regression model was used to estimate the crude and adjusted prevalence ratios (PR) of the outcomes and respective 95% confidence intervals according to the characteristics of the sample.

RESULTS

In total, 1,161 elderly people were followed up. The prevalence of participants who reported requiring help with medication was 15.5% (95%CI 13.5-17.8), and the oldest subjects, with lower educational levels, in worse economic situations, on four or more medications and in bad self-rated health were the ones who needed help the most. Continuous use of medication was reported by 83.0% (95%CI 80.7-85.1) of the sample and most participants (74.9%; 95%CI 72.0-77.5) never forgot to take their medications.

CONCLUSION

The need for help to use medications was shown to be influenced by social and economic determinants. Studies assessing the difficulties in medication use by the elderly are important to support policies and practices to improve adherence to treatment and the rational use of medications.

Prevalence of tooth wear and associated factors: A birth cohort study

OBJECTIVES

To investigate the prevalence of tooth wear and associated factors in adults from the 1982 Pelotas Birth Cohort.

METHODS

A subsample of the 5,914 individuals from the 1982 Pelotas Birth Cohort was randomly selected to be interviewed and clinically examined at the age of 31. Tooth wear was evaluated using a simplified version of the Tooth Wear Index (TWI), considering the absence or presence of tooth wear in dentin of first molars and anterior teeth (incisors and canines). Independent variables were socioeconomic, demographic, unhealthy behavior, and mental health. Crude and adjusted Poisson regression models were employed. A significant level of P ≤ 0.05 was adopted.

RESULTS

A total of 537 individuals were evaluated. A tooth wear prevalence of 61.6% was observed. Females presented a statistically significant lower tooth wear in dentin prevalence ratio (PR) compared to males in the adjusted analysis (PR 0.76; 95% CI: 0.67-0.86). Acid beverage consumption (PR 1.22; 95% CI: 1.01-1.49) and consumption of alcoholic beverages (PR 1.19; 95% CI: 1.04-1.35) were positively associated with tooth wear.

CONCLUSION

Almost 2/3 of the surveyed individuals presented tooth wear in dentin. Being a male, higher consumption of alcohol and acidic beverages were factors associated with tooth wear.

CLINICAL SIGNIFICANCE

There was a high prevalence of tooth wear in dentin in the adult population. Data has also shown the etiological complexity of tooth wear, reinforcing the importance of an early diagnosis and the establishment of preventive measures to decrease the potentially hazardous effect of tooth wear over time.

Difficulties in the use of medications by elderly people followed up in a cohort study in Southern Brazil

Objective:

This study aimed to assess the need for help by elderly people to take their medications, the difficulties related to this activity, the frequency of forgotten doses, and factors associated.

Methods:

Cross-sectional study conducted with a cohort of elderly people (60 years and over — “COMO VAI?” [How do you do?] study), where the need for help to properly take medication and the difficulties faced in using them were evaluated. The Poisson regression model was used to estimate the crude and adjusted prevalence ratios (PR) of the outcomes and respective 95% confidence intervals according to the characteristics of the sample.

Results:

In total, 1,161 elderly people were followed up. The prevalence of participants who reported requiring help with medication was 15.5% (95%CI 13.5–17.8), and the oldest subjects, with lower educational levels, in worse economic situations, on four or more medications and in bad self-rated health were the ones who needed help the most. Continuous use of medication was reported by 83.0% (95%CI 80.7–85.1) of the sample and most participants (74.9%; 95%CI 72.0–77.5) never forgot to take their medications.

Conclusion:

The need for help to use medications was shown to be influenced by social and economic determinants. Studies assessing the difficulties in medication use by the elderly are important to support policies and practices to improve adherence to treatment and the rational use of medications.

Trajectories of Sugar Consumption and Dental Caries in Early Childhood

This study verifies the association between the trajectory of sugar consumption and dental caries in the 2015 Pelotas Birth Cohort in Pelotas, Brazil. It was conducted with data from the follow-ups at 3, 12, 24, and 48 mo from the 2015 Birth Cohort, which included 4,275 children born alive in hospitals in Pelotas. Data collection included standardized questionnaires for first caregivers applied by trained interviewers at all follow-ups. Exposure was the trajectory of sugar consumption from 3 to 48 mo (always low, always intermediate, increasing, and always high), obtained by group-based trajectory modeling. The outcome of this study was dental caries, obtained through clinical examination performed by calibrated dentists at 48 mo of age. Socioeconomic conditions and oral health instruction from a health professional during the first 4 y of life were included in the analysis as potential confounders. Prevalence ratios and their 95% confidence intervals were provided from generalized estimating equations with a log-Poisson with robust variance specification. In total, 3,654 (91.1%) children participated in the survey at 48 mo, and 2,806 children had complete data for the analyzes performed. Of these, 1,012 (36.1%; 95% confidence interval [CI], 34.3-37.8) experienced caries, and 723 (25.8%; 95% CI, 24.2-27.4) had cavitated caries. Regarding cavitated caries, the prevalence was 1.48 times higher in the group with increasing sugar consumption than children with always low consumption. There is an association between the trajectory of sugar consumption and dental caries at 48 mo. Children with increasing and always high sugar consumption have the highest prevalence of caries.

Dentist’s preferences on vital and nonvital tooth bleaching

 Aim: The present study aimed to investigate if the Guatemalan dentist’s options on tooth bleaching could be influenced by their time in clinical practice, the level of specialization or their working place. Methods: A representative sample of dentists working in clinical practice in Guatemala was selected. Data were collected using a self-administered questionnaire with information related to gender, professional characteristics (time since graduation in years and working place) and preferences regarding vital (at-home or in-office; type and concentration of bleaching agent) and the nonvital tooth bleaching (bleaching agent used). The analysis was performed and the association between preference for bleaching technique and independent variables were investigated using Fisher’s exact test. Results: 200 dentists were interviewed. More than half of dentists were male (57.0%) with time since graduation between 11 and 20 years (n= 64; 32.3%). Dentists mostly (60.5%) preferred in-office technique for vital bleaching, with 10-20% Carbamide peroxide (CP) as the preferred agent (50%). For nonvital teeth, the preferred agent (46.8%) was 37% Hydrogen Peroxide (HP). About the associations, younger dentists (< 20 years of graduation) selected mostly in-office technique, while those with more than 20 years indicated more the at-home technique. Also, the dentists working in private practice chose more frequently in-office technique. Thus, the in-office technique was more popular among Guatemalan dentists, with 10-20% CP and 37% HP selected as favorite bleaching agents for vital and nonvital techniques, respectively. Conclusion: The time of clinical practice and working place influenced some choices.  

[Is oral health associated with the presence of depressive symptoms among the elderly?]

The scope of this study was to describe the prevalence of depressive symptoms measured by the Geriatric Depression Scale-EDG - 15 and test the association of oral health variables and depressive symptoms in a population of the elderly linked to eleven Family Health Units in the south of Brazil. It involved a cross-sectional study with 439 elderly individuals. A standardized questionnaire was used to obtain socio-economic and oral health variables of the study. The clinical variables of oral health were obtained by a qualified dentist. The symptoms of depression, which was the scope of the study, were obtained by the Geriatric Depression Scale-EDG -15. The prevalence of depressive symptoms was 18.3% (CI95% 14.6-21.8). Analyzing the exposure variables and depressive symptoms through adjusted Poisson regression analysis, individuals with 1 to 9 teeth (PR = 1.68; CI95% 1.06-2.64, p = 0.012), with a perception of dry mouth (PR = 2.23; CI95% 1.52-3.28, p < 0.001) and perception of pain in the mouth (PR = 2.11; CI95% 1.10-4.07, p = 0.036) have a higher prevalence of depressive symptoms. The study identified a significant prevalence of depressive symptoms and that oral health variables are associated with the presence of depressive symptoms in the elderly population.

The Controlled Direct Effect of Early-Life Socioeconomic Position on Periodontitis in a Birth Cohort

This study used data from the 1982 Pelotas Birth Cohort Study, Brazil, to estimate the controlled direct effect of early-life socioeconomic position (SEP) on periodontitis at age 31 years, controlling for adulthood income and education, smoking, and dental hygiene. Sex was included as a covariate. Early-life SEP was measured at participant birth based on income, health services payment mode, maternal education, height, and skin color (lower versus middle/higher SEP). Periodontitis was assessed through clinical examination at age 31 years (healthy, mild periodontitis, or moderate-to-severe disease). Adulthood behaviors (smoking, dental hygiene) were the mediators, and adulthood SEP (education and income) represented the exposure-induced mediator-outcome confounders. A regression-based approach was used to assess the controlled direct effect of early-life SEP on periodontitis. Multinomial regression models were used to estimate risk ratios and their 95% confidence intervals. The prevalences of mild and moderate-to-severe periodontitis were 23.0% and 14.3%, respectively (n = 539). Individuals from the lowest early-life SEP had a higher risk of moderate-to-severe periodontitis controlled for mediators and exposure-induced mediator-outcome confounders: risk ratio = 1.85 (95% confidence interval: 1.06, 3.24), E value 3.1. We found that early-life SEP was associated with the development of periodontitis in adulthood that was not mediated by adulthood SEP and behaviors.

How Common is Dry Mouth? Systematic Review and Meta-Regression Analysis of Prevalence Estimates

The aim of this paper is to systematically review the literature to estimate the overall prevalence of xerostomia/hyposalivation in epidemiological studies. An electronic search was carried out up to February 2018 with no language restrictions. A total of 5760 titles were screened and just twenty-nine papers were included in review and the meta-analysis after a two independently reviewers applied the selection criteria. Data were extracted from PubMed and Web of Science databases. Eligibility criteria included original investigations from observational population-based studies that reported the prevalence of xerostomia or data that allowed the calculation of prevalence of xerostomia and/or hyposalivation. Studies conducted in samples with specific health conditions, literature reviews, case reports and anthropological studies, as conferences or comments were excluded. Sample size, geographic location of the study, study design, age of the studied population, diagnosis methods, and evaluation criteria used to determine xerostomia e/or hyposalivation were extracted for meta-analysis and meta-regression. Multivariate meta-regression analysis was performed to explore heterogeneity among studies. The overall estimated prevalence of dry mouth was 22.0% (95%CI 17.0-26.0%). Higher prevalence of xerostomia was observed in studies conducted only with elderly people. Despite diverse approaches to the condition's measurement, just over one in four people suffer from xerostomia, with higher rates observed among older people. Moreover, the measurement methods used currently may over- or underestimate xerostomia. These findings highlight the need for further work on existing and new clinical measure and will be useful to determine which one is more reliable in clinical and epidemiological perspectives.

Is depression associated with oral health outcomes in adults and elders? A systematic review and meta-analysis

OBJECTIVES

To systematically review the literature in order to investigate association between depression and oral diseases.

MATERIAL AND METHODS

Electronic searches were performed in five databases. Studies testing associations between depression and oral diseases as either exposure or outcome were included. Oral disease variable included any tooth loss or edentulism, periodontal disease, and dental caries.

RESULTS

A total of 2504 articles were identified in the electronic database search. Sixteen studies were included in this systematic review being 14 included in the meta-analyses. Eleven studies considered oral health as outcome, whereas three studies considered depression as an outcome variable. Depression was associated to dental caries, tooth loss, and edentulism. Pooled estimates showed that depression increased the odds of dental caries (OR 1.27; 95% CI 1.13-1.44), tooth loss (OR 1.31; 95% CI 1.24-1.37), and edentulism (OR 1.17; 95% CI 1.02-1.34), respectively. When the oral diseases were tested as independent variable and depression as outcome, associations with both edentulism (OR 1.28; 95% CI 1.06-1.55) and periodontal disease (HR 1.73; 95% CI 1.58-1.89) were found.

CONCLUSIONS

The results of our systematic review and meta-analyses show a positive association between depression and oral diseases, specifically dental caries, tooth loss, and edentulism, in adults and elders. More longitudinal studies are required to test causal and temporal relationship between depression and oral health status.

CLINICAL RELEVANCE

Mental and oral health are among the main disabilities worldwide. This article helps to understand more about the relationship between both conditions, highlighting the importance for both clinicians and policy makers of considering individual's psychological status in management of oral health.

The role of asthma in caries occurrence - meta-analysis and meta-regression

Objective: We aimed to conduct a systematic review of the literature regarding the association between asthma and caries, assess the effect of asthma on the occurrence of caries in primary and permanent dentitions, and determine factors that could affect the estimates of this association. Data source: We used the following databases: PubMed, Web of Science, SCOPUS, and LILACS/BVS, for the literature review. Study selection: We included observational studies that investigated the association between asthma and dental caries, excluding studies with syndromic patients, literature reviews, case reports, and in vitro and in situ studies. A meta-analysis was performed to estimate a pooled effect, and meta-regression was conducted to determine study factors that could affect the estimates. Results: From 674 studies initially identified, 40 fulfilled the inclusion criteria, and 36 of these were used in the meta-analysis. Odds ratio (OR) for the pooled effect was 1.45 (95% confidence interval (CI): 1.22-1.72; I², 71.8%; p < 0.001) and 1.52 (95% CI: 1.34-1.73; I², 83.1%; p < 0.001) for primary and permanent dentitions, respectively. In addition, a small proportion of the heterogeneity was attributed to included factors in the meta-regression (primary dentition, 10.7%; and permanent dentition, 3.1%). Conclusions: This study provides reliable and robust evidence that emphasizes the impact of asthma on the occurrence of dental caries in both, primary and permanent, dentitions. The findings provide useful data for recommending that dentists and physicians collaborate to establish the control for both diseases in a multidisciplinary manner.

Revascularization versus apical barrier technique with mineral trioxide aggregate plug: A systematic review

Aim: To compare the clinical and radiographic outcomes observed in Necrotic Immature Permanent Teeth (NIPT) after revascularization or apexification with MTA-apical plug. Methodology: PubMed/MEDLINE, Web of science and Scopus were the databases used, up to July 30th, 2017, for article research. Independent reviewers read the titles and abstracts of all reports that met inclusion/exclusion criteria: prospective or retrospective clinical studies comparing the revascularization of root canal and apexification. Clinical success of therapies, deposition and thickening of lateral dentinal walls (root width) and the continuation of root development (root length) were investigated. Bias risk of included studies was assessed using the Cochrane risk of bias. Results: From 1642 records, five papers fulfilled all inclusion criteria. Overall, 91 teeth were submitted to revascularization and 64 teeth to apexification with MTA. The mean follow-up was 23.2 months in revascularization and 21.8 in apexification. Clinical success rate was of 87.9% in the revascularization group and 90.6% in the apexification group. An increase on lateral dentinal walls thickening was observed in most revascularization cases (13%) while MTA as apical plug suggest a mild resorption of the root (1.3%). High bias risk was observed on included studies. Conclusions: Apexification with MTA-apical plug provides similar clinical success to revascularization. However, radiographic measurements showed an improvement in thickening of lateral dentinal walls in most of the revascularization cases in addition to a higher dental development. However, these results should be interpreted with caution.

Influence of maternal psychological traits on sleep bruxism in children

BACKGROUND

Sleep bruxism (SB) is a sleep disorder with high incidence in toddlers and may perpetuate to adulthood. The multifactorial etiology of bruxism includes pathophysiologic and psychological factors.

AIM

To investigate the relationship between depression, stressful events, and the presence of symptoms of anxiety and depression with SB in children of adolescent mothers.

DESIGN

This cross-sectional study nested in a cohort evaluated a sample of 536 mothers and their children aged 24-36 months. Interviews were conducted with mothers. Maternal report of SB was collected. Mother's major depressive disorder was assessed using the Mini International Neuropsychiatric Interview (MINI Plus); Life Events Scale assessed the stressful events; Beck Depression Inventory and Beck Anxiety Inventory investigated the symptoms of depression and anxiety. Poisson regression analysis was applied to assess the association of maternal psychological disorders and stressful events with SB on children.

RESULTS

Prevalence of SB was 25.93% (95% CI 22.2-29.7). After adjustments, maternal major depression disorder [PR 1.43 (95% CI 1.06-1.92)] and the presence of stressful events mainly environmental changes [PR 1.47 (95% CI 1.08-2.00)] showed significant association with bruxism in children.

CONCLUSION

This study showed a positive association between mother's psychological traits and SB development in their toddlers.

Impact of Prolonged Breastfeeding on Dental Caries: A Population-Based Birth Cohort Study

BACKGROUND

Few studies have assessed the effect of breastfeeding, bottle feeding, and sugar consumption on children's dental caries. We investigated whether the duration of breastfeeding is a risk factor for dental caries in the primary dentition, independently of sugar consumption.

METHODS

An oral health study (n = 1303) nested in a birth cohort study was carried out in southern Brazil. The average number of decayed, missing, and filled primary tooth surfaces (dmfs) and severe early childhood caries (S-ECC: dmfs ≥6) were investigated at age 5 years. Breastfeeding was the main exposure collected at birth and at 3, 12, and 24 months of age. Data on sugar consumption were collected at 24, 48, and 60 months of age. Marginal structural modeling was used to estimate the controlled direct effect of breastfeeding (0-12, 13-23, and ≥24 months) on dmfs and on S-ECC.

RESULTS

The prevalence of S-ECC was 23.9%. The mean number of dmfs was 4.05. Children who were breastfed for ≥24 months had a higher number of dmfs (mean ratio: 1.9; 95% confidence interval: 1.5-2.4) and a 2.4 times higher risk of having S-ECC (risk ratio: 2.4; 95% confidence interval: 1.7-3.3) than those who were breastfed up to 12 months of age. Breastfeeding between 13 and 23 months had no effect on dental caries.

CONCLUSIONS

Prolonged breastfeeding increases the risk of having dental caries. Preventive interventions for dental caries should be established as early as possible because breastfeeding is beneficial for children's health. Mechanisms underlying this process should be investigated more deeply.

Restoration Survival: Revisiting Patients' Risk Factors Through a Systematic Literature Review

A literature review was conducted to investigate the influence of patient-related factors on restoration survival in posterior permanent teeth as well as to report the methods used to collect these factors. The selection of articles on longitudinal clinical studies investigating the survival of posterior restorations (except full crowns and temporary fillings) and including patient-related factors was performed by applying predefined criteria. The review was organized into two parts, the first describing how patient factors were assessed in the studies (n=45) and the second presenting the statistical significance (n=27) and size of the effect (n=11) of these factors on restoration survival. Patient-related factors mentioned in the studies included age; gender; caries risk; caries activity/severity; decayed, missing, filled teeth; number of restorations; oral hygiene; and bruxism, among others. Sixteen studies included the patient age or age range in the analysis, which was found to be significant in 47% of the studies. Regarding gender, four of 17 reports found a significant effect on survival, showing more failures for men in three studies. The caries risk profile or related variables were included in the analysis of 15 studies, and a significant effect on survival was reported for high-caries-risk individuals (or related variables) in 67% of these studies. Bruxism was also found to influence restoration survival in three of six studies where this variable was investigated. Some issues were found regarding the reporting of methods used to classify patients according to risk and were thoroughly discussed. In view of the information gathered in this review, the assessment of patient factors along with other variables should become part of clinical studies investigating restoration survival, since several of these factors were shown to influence the failure of restorations, regardless of the material type.

Is there a relationship between obesity and tooth loss and edentulism? A systematic review and meta-analysis

This study conducted a systematic review to assess the bi-directional association between tooth loss/edentulism and obesity. Electronic searches were performed in four different databases. Observational studies that tested associations between tooth loss/edentulism and obesity as either exposures or outcomes were included. Additionally, meta-analyses, funnel plots and sensitivity analyses were conducted to synthesize the evidence. A total of 549 articles were identified in the electronic database search. Out of which, 16 studies were included within the meta-analyses: 75% considered tooth loss/edentulism as exposure and obesity as outcome, whereas 25% alternatively considered obesity as exposure and tooth loss/edentulism as outcome. Pooled estimates showed that obese individuals had 1.49 (95%CI 1.20-1.86) and 1.25 (95%CI 1.10-1.42) times higher odds of having any tooth loss and edentulism, respectively. Alternatively, when tooth loss or edentulism were considered as exposures, individuals with any tooth loss had 1.41 (95%CI 1.11-1.79) times higher odds for obesity, while edentates had even higher odds (OR 1.60; 95%CI 1.29-2.00). The results indicate a bi-directional association between tooth loss and obesity. Considering that all selected studies were of cross-sectional study design limiting inferences on temporality, longitudinal prospective studies are required to test the causal relationship between tooth loss/edentulism and obesity or vice a versa. © 2016 World Obesity.

Sugar Consumption and Changes in Dental Caries from Childhood to Adolescence

There are no prospective studies investigating the effects of sugar-related feeding practices on changes in dental caries from early childhood to young adulthood. The aim of this study was to assess whether sugar-related feeding practices affect dental caries between the ages of 6 and 18 y. This birth cohort study was initiated in 1993 in Pelotas, Brazil. There were 3 dental clinical assessments; at ages 6 y (n = 359), 12 y (n = 339), and 18 y (n = 307). Sugar-related feeding practices were assessed at ages 4, 15, and 18 y. Covariates included sex and life course variables, such as family income, breast-feeding, mother's education, regularity of dental visit, and child's toothbrushing habits. Group-based trajectory analysis was performed to characterize trajectories of time-varying independent variables that had at least 3 time points. We fitted a generalized linear mixed model assuming negative binomial distribution with log link function on 3-time repeated dental caries assessments. One in 5 participants was classified as "high" sugar consumers, and nearly 40% were "upward consumers." "Low consumers" accounted for >40% of the sample. High and upward sugar consumers had higher dental caries prevalence and mean DMFT in all cohort waves when compared with low sugar consumers. Caries occurred at a relatively constant rate over the period of study, but in all sugar consumption groups, the increment of dental caries was slightly higher between ages 6 and 12 y than between 12 and 18 y. Adjusted analysis showed that dental caries increment ratio between ages 6 and 18 y was 20% and 66% higher in upward and high sugar consumer groups as compared with low consumers. The higher the sugar consumption along the life course, the higher the dental caries increment. Even the low level of sugar consumption was related to dental caries, despite the use of fluoride.

Tooth loss and associated factors in elders: results from a national survey in Uruguay

OBJECTIVES

This study evaluated the prevalence and severity of tooth loss in Uruguayan elders, assessing its association with demographic, socioeconomic, and behavioral factors; the use of health services; and self-reported dental treatment need.

METHODS

A population-based cross-sectional study was done among Uruguayan individuals of ages 65-74 years. Data were collected through questionnaires and clinical examinations. The dependent variable, tooth loss, was classified into three distinct outcomes: functional dentition (≥20 teeth), severe tooth loss (<9 teeth), and edentulism. The independent variables were: sex, socioeconomic status, use of health services, hypertension, diabetes mellitus, tobacco use, frequent consumption of alcohol, hygiene habits, and need for dental care.

RESULTS

The sample comprised 341 individuals, and the mean number of teeth present was 9.73 (95% confidence interval, 8.77-10.69) for each individual. After multivariate analysis, lack of a functional dentition, severe tooth loss, and edentulism were found to be associated with lower socioeconomic level, frequent consumption of alcohol, and receiving treatment from the public health system (P < 0.05). Individuals with self-reported dental treatment need had more severe tooth loss and presented a higher degree of edentulism (P < 0.05).

CONCLUSIONS

There is a high and severe prevalence of tooth loss in elderly Uruguayans, especially among those from lower socioeconomic levels. Our findings highlight the importance of public health policies to prevent and treat tooth loss.

Randomized controlled clinical trial of the 24-months survival of composite resin restorations after one-step incomplete and complete excavation on primary teeth

OBJECTIVE

This randomized clinical trial aimed to compare the 24-months survival of composite restorations in primary molars after partial caries removal (PCR) and total caries removal (TCR).

METHODS

Forty-eight children aged 3-8 years with at least one molar with a deep carious lesion were included (PCR; n=66; TCR; n=54). For PCR, excavation was stopped when dentine with a leathery consistency was achieved; in the TCR group, total absence of carious tissue was confirmed using a blunt-tipped probe. Pulpotomy was performed in cases of pulp exposure. Success was assessed by modified USPHS criteria with Alpha and Bravo scores recorded as success.

RESULTS

Pulp exposure occurred in 1 and 15 of the teeth treated with PCR and TCR respectively (p<0.01). The restorations survival rate after 24 months was 66% (PCR) and 86% (TCR) (p=0.03). When teeth that received pulpotomy were analyzed separately, the survival rate was 92% (p=0.09). PCR performed in occlusoproximal restorations demonstrated the lowest success rate (p=0.002). PCR increases 2.90 times the probability of having a restorative failure compared to TCR (p=0.03), after adjusting for cavity type. When pulp exposure and restoration failure were considered as the outcome, there was no significant difference between the two groups (p=0.10) with success rates of 64% (PCR) and 61% (TCR).

CONCLUSION

Collectively, deciduous teeth submitted to PCR prevented pulp exposure and, consequently, more invasive treatments; otherwise, PCR yielded lower longevity for composite restoration compared to TCR, suggesting that PCR restorations need to be followed over time, especially when multi-surface restorations are involved.

CLINICAL SIGNIFICANCE

Composite restorations on carious remaining tissue require monitoring over time, especially those performed in more than one surface. Even if the restorations present shortcomings over the time, the majority of them are subject to repair, allowing more conservative approaches for teeth with deep caries lesions.

Stem cell-based pulp tissue engineering: variables enrolled in translation from the bench to the bedside, a systematic review of literature

Stem cell-based therapy (SC-BT) is emerging as an alternative for endodontic therapies. The interaction between stem cells and scaffolds plays a crucial role in the generation of a 'friendly cell' microenvironment. The aim of this systematic review was to explore techniques applied to regenerate the pulp-dentine complex tissue using SC-BT. An electronic search into the SciVerse Scopus (SS), ISI Web Science (IWS) and Entrez PubMed (EP) using specific keywords was performed. Specific inclusion and exclusion criteria were predetermined. The search yielded papers, out of which full-text papers were included in the final analyses. Data extraction pooled the results in four main topics: (a) influence of the chemical properties of the scaffolds over cell behaviour; (b) influence of the physical characteristics of scaffolds over cell behaviour; (c) strategies applied to improve the stem cell/scaffold interface; and (d) influence of cue microenvironment on stem cell differentiation towards odontoblast-like cells and pulp-like tissue formation. The relationship between the scaffolds, the environment and the growth factors released from dentine are critical for de novo pulp tissue regeneration. The preconditioning of dentine walls with ethylenediaminetetraacetic acid (EDTA) was imperative for successful pulp-dentine complex regeneration. An analyses of the grouped results revealed that pulp regeneration was an attainable goal.

Exclusive Breastfeeding and Risk of Dental Malocclusion

OBJECTIVES

The distinct effect of exclusive and predominant breastfeeding on primary dentition malocclusions is still unclear. We hypothesized that exclusive breastfeeding presents a higher protective effect against malocclusions than predominant breastfeeding and that the use of a pacifier modifies the association between breastfeeding and primary dentition malocclusions.

METHODS

An oral health study nested in a birth cohort study was conducted at age 5 years (N = 1303). The type of breastfeeding was recorded at birth and at 3, 12, and 24 months of age. Open bite (OB), crossbite, overjet (OJ), and moderate/severe malocclusion (MSM) were assessed. Poisson regression analyses were conducted by controlling for sociodemographic and anthropometric characteristics, sucking habits along the life course, dental caries, and dental treatment.

RESULTS

Predominant breastfeeding was associated with a lower prevalence of OB, OJ, and MSM, but pacifier use modified these associations. The same findings were noted between exclusive breastfeeding and OJ and between exclusive breastfeeding and crossbite. A lower prevalence of OB was found among children exposed to exclusive breastfeeding from 3 to 5.9 months (33%) and up to 6 months (44%) of age. Those who were exclusively breastfed from 3 to 5.9 months and up to 6 months of age exhibited 41% and 72% lower prevalence of MSM, respectively, than those who were never breastfed.

CONCLUSIONS

A common risk approach, promoting exclusive breastfeeding up to 6 months of age to prevent childhood diseases and disorders, should be an effective population strategy to prevent malocclusion.

Estimated prevalence of erosive tooth wear in permanent teeth of children and adolescents: an epidemiological systematic review and meta-regression analysis

OBJECTIVES

The main purpose of this systematic review was to estimate the prevalence of dental erosion in permanent teeth of children and adolescents.

METHODS

An electronic search was performed up to and including March 2014. Eligibility criteria included population-based studies in permanent teeth of children and adolescents aged 8-19-year-old reporting the prevalence or data that allowed the calculation of prevalence rates of tooth erosion. Data collection assessed information regarding geographic location, type of index used for clinical examination, sample size, year of publication, age, examined teeth and tissue exposure. The estimated prevalence of erosive wear was determined, followed by a meta-regression analysis.

RESULTS

Twenty-two papers were included in the systematic review. The overall estimated prevalence of tooth erosion was 30.4% (95%IC 23.8-37.0). In the multivariate meta-regression model use of the Tooth Wear Index for clinical examination, studies with sample smaller than 1000 subjects and those conducted in the Middle East and Africa remained associated with higher dental erosion prevalence rates.

CONCLUSIONS

Our results demonstrated that the estimated prevalence of erosive wear in permanent teeth of children and adolescents is 30.4% with high heterogeneity between studies. Additionally, the correct choice of a clinical index for dental erosion detection and the geographic location play an important role for the large variability of erosive tooth wear in permanent teeth of children and adolescents.

CLINICAL SIGNIFICANCE

The prevalence of tooth erosion observed in permanent teeth of children and adolescents was considerable high. Our results demonstrated that prevalence rate of erosive wear was influenced by methodological and diagnosis factors. When tooth erosion is assessed, the clinical index should be considered.

Direct or indirect composite veneers in anterior teeth: which method causes higher tooth mass loss? An in vitro study

There is little information in the literature regarding the relationship between preparations made for direct and indirect veneers and the loss of tooth structure required for each technique. This in vitro study sought to quantify the different mass losses from preparation techniques used for direct and indirect veneers. Thirty artificial teeth were weighted using a digital balance and placed in a dental manikin in the position corresponding to the right maxillary central incisor. Five clinicians-all experts in esthetic dentistry-were asked to perform conventional preparations for both a direct composite resin veneer and an indirect ceramic veneer. After preparations, specimens were weighted again in the same digital balance. Teeth undergoing veneer preparations demonstrated a statistically significant mass loss compared to unprepared teeth. Indirect ceramic veneer preparations produced more mass loss than direct composite veneer preparations (P < 0.01).

A double-blind randomised clinical trial of two techniques for gingival displacement

Knowledge about security and the potential damage originated by the gingival displacement techniques has not been described through randomised clinical studies. This crossover, double-blind, randomised clinical trial evaluated clinical and immunological factors related to conventional and cordless gingival displacement (GD) techniques, and patients' perceptions in 12 subjects with the employment of 2 GD techniques: conventional (gingival cord + 25% AlCl3 astringent gel) and cordless (15% AlCl3 astringent-based paste). In each subject, two anterior teeth were treated and a 10-day wash-out period separated the two treatments. Periodontal indices were evaluated before (baseline) and 1 and 10 days after GD. Interleukin 1β, interleukin 6 and tumour necrosis factor α concentrations in gingival crevicular fluid were measured before and 1 day after GD. Subjective parameters (pain, unpleasant taste and stress) were also evaluated. Data were analysed by one-way repeated-measures analysis of variance and Tukey's test (immunological factors), the Friedman test (periodontal parameters) and Fisher's exact or chi-squared test (subjective parameters), with a significance level of 95%. Gingival bleeding index, probing depth and plaque index values did not differ significantly between groups at any timepoint. Neither technique resulted in worse periodontal indices. Both techniques yielded similar results for pain and unpleasant taste, but conventional GD was significantly more stressful than cordless GD for volunteers. Both treatments significantly increased mean concentrations of the three cytokines, with the conventional technique producing the highest cytokine levels. Cordless GD is less stressful for patients and results in lower post-treatment levels of inflammatory cytokines compared with conventional GD.

Oncogenic somatic events in tissue-specific stem cells: a role in cancer recurrence?

Tissue-specific stem cells (TSSCs) are a very unique cell type, with critical and well-defined roles for the homeostasis of high turnover tissues (such as the blood and the skin). Emerging evidence suggests that TSSCs are implicated in malignancies, with several theories being proposed and tested, including many attempts to identify the cells of origin and studies deigned to understand how TSSCs participate in age-related increase in cancer risk. A currently unexplored possibility in this respect is the plausible theory that an oncogenic event that arises at a TSSC would promote tissue replenishment by cells containing these mutations, with progressive propagation of such mutated TSSCs in the niche. Therefore, the effect of a somatic oncogenic event in a single TSSC may have more important implications than previously anticipated, resulting in sustained and progressively higher cancer risk. This model could have important implications for tumor recurrence, since in some cases the underlying cause might be the development of a new tumor originated from daughter cells of the TSSC that suffered the first oncogenic hit, rather than proliferation of residual cancer cells. In this review, we present and discuss approaches for testing the proposed theory of tumorigenesis and cancer risk, as well as practical implications for biomedical research and clinical practice.

Obesity and dental caries: systematic review

OBJECTIVE Identifying, through a systematic literature review, evidence of a possible association between obesity and dental caries. METHODS A search of articles published between 2005 and January 2012 was performed in the Medline/PubMed, LILACS and Web of Science databases. The quality of scientific evidence of the selected articles was assessed by the items proposed for observational studies in the Downs & Black instrument. RESULTS Initially, 537 references were found; after checking the titles and abstracts by two independent researchers, twenty-eight articles were selected for complete reading. Ten of them that assessed the primary and/or permanent dentition observed a positive association between obesity and dental caries and one study found an inverse association. According to the Downs & Black classification, thirteen articles with good scientific evidence were found. CONCLUSIONS The present review did not find sufficient evidence regarding the association between obesity and dental caries, and it did not clarify the possible role of diet and other possible effect modifiers on this association.

Tenascin and Fibronectin Expression after Pulp Capping with Different Hemostatic Agents: A Preliminary Study

This study investigated the expression of extracellular matrix glycoproteins tenascin (TN) and fibronectin (FN) in pulp repair after capping with calcium hydroxide (CH), following different hemostasis protocols. Class I cavities with a pulp exposure were prepared in 42 human third molars scheduled for extraction. Different hemostatic agents (0.9% saline solution, 5.25% sodium hypochlorite and 2% chlorhexidine digluconate) were used and pulps were capped with CH cement. After 7, 30 or 90 days, teeth were extracted, formalin-fixed, and prepared for immunohistochemical technique. Hemostatic agents did not influence the expression of TN and FN. Both glycoproteins were found in the entire the pulp tissue and around collagen fibers, but were absent in the mineralized tissues. In the predentin, TN showed positive immunostaining and FN had a variable expression. Within 7 days post-treatment, a slightly more pronounced immunostaining on the pulp exposure site was observed. Within 30 days, TN and FN demonstrated a positive expression around the dentin barrier and at 90 days, a thin and linear expression of TN and FN was delimitating the reparative dentin. In conclusion, hemostatic agents did not influence TN and FN expression. Immunostaining for TN and FN was seen in different regions and periods, demonstrating their role in pulp repair.

Influence of different photo-activation distances on cytotoxicity of a dental adhesive model resin

AIM

This study evaluated the cytotoxicity of a dental bonding model resin (DBMR) submitted to different photo-activation distances.

METHODS

A monomer mixture based on Bis-GMA and HEMA was used to assess the cytotoxicity in a mouse fibroblast-cell line. To promote different photo-activation distances glass slides were interposed between DBMR surface and halogen light curing unit (LCU) tip. Afterwards, the specimens were immersed in RPMI culture medium for 24 h to obtain extracts. The extracts were incubated in contact with the cells for 24 h. Finally, an MTT colorimetric assay was used to assess the cytotoxicity. The cell viability data (absorbance) were analyzed by one way ANOVA followed by Tukey's test (P<0.05).

RESULTS

The light output decreased according to the increase in the number of glass slides between the halogen LCU tip and DBMR surface. Yet, the distance between the tip of the curing light system and the specimens had significant influence on the cytotoxicity. All extracts produced by groups submitted to different photo-activation distances showed cytotoxic effect after 24h of incubation.

CONCLUSION

The photo-activation distance and the interposition of glass slides between LCU tip and DBMR was shown to play an important role in the cytotoxic effect.

Caries is the main cause for dental pain in childhood: findings from a birth cohort

AIM

The aim of the study was to evaluate the prevalence of dental pain in preschool children and its association with socioeconomic, demographic, clinical, and behavior variables.

SUBJECTS AND METHODS

The study was nested in a population-based birth cohort from Pelotas, Brazil, started in 2004. A sample of 1,129 children aged 5 years was dentally examined, and their mothers were interviewed. Exploratory variables included demographics, socioeconomic status, mothers' oral health status and associated behaviors, and caries in primary teeth. Data were analyzed using multivariable Poisson regression.

RESULTS

The prevalence of dental pain was 16.5% (95% CI: 14.4-18.8). Multivariate analysis showed that dark-skinned children (prevalence ratio, PR = 1.6, 95% CI: 1.1-2.4) from low socioeconomic level (PR 1.9, 1.2-3.0) whose mothers had less than 4 years of education (PR 1.9, 1.0-3.6), from mothers with less than 10 teeth in at least one arch (PR 1.7, 1.2-2.5) and less than 10 in two arches (PR 1.6, 1.0-2.6), and those with high caries prevalence at the age of 5 years (PR 4.8, 3.3-7.1) were more likely to experience dental pain.

CONCLUSIONS

Unrestored caries is the main factor associated with dental pain in childhood. Socioeconomic aspects and family context in which dental pain occurs should also be taken into account when dental pain preventive measures are implemented.

Odontoblast RNA stability in different temperature-based protocols for tooth storage

AIM

To evaluate the effect of four tooth storage temperature-based methods on quality of RNA obtained from cells retrieved from human dental pulps and human pre-dentine.

METHODOLOGY

RNA was isolated from dental pulp tissue and from cells retrieved by scraping the pre-dentine of freshly extracted human third molars (n = 15) using TRIzol(®) reagent. Teeth were randomly assigned to the following temperature conditions: immediate RNA isolation after tooth extraction, liquid nitrogen (24 h), -80 °C (24 h), 20 °C (24 h) and 4 °C (6 h). RNA integrity was checked by the density of 28S and 18S ribosomal RNA. RT-PCR was used to analyse the expression of odontoblast makers (DSPP, DMP1 and MEPE) and the housekeeping gene GAPDH.

RESULTS

All experimental conditions evaluated preserved RNA integrity. The three odontoblastic markers were amplified from the pulp tissue and from the cells associated with pre-dentine.

CONCLUSION

The four storage options allowed RNA isolation for RT-PCR analysis. These findings may facilitate the use of clinically derived human dental pulp and odontoblasts for endodontic research.

Influence of maternal dental anxiety on the child's dental caries experience

This study assessed the influence of maternal dental anxiety-related behavior on the child's caries experience. A cross-sectional study with 608 mother-child dyads during the Children's National Immunization Campaign in Pelotas, Brazil was performed. Mothers were asked to answer a questionnaire and dental examination of the children was performed (dmft). The association assessment used Poisson regression. Children from anxious mothers were more likely to present untreated caries even after covariate adjustment. Boys, older children and low-income family children presented a higher dmft mean. Preventive strategies should focus not only on child and family characteristics, but also on maternal dental anxiety-related behaviors.

Survey on the occurrence of dental trauma and preventive strategies among Brazilian professional soccer players

Objectives

The aims of this study were to verify the occurrence of dental injuries in professional Brazilian soccer players, the level of knowledge of the teams' medical departments about mouthguards, and the conducts adopted in cases of dental trauma during the match.

Material and methods

Closed questionnaires were sent to the physicians in charge of the medical departments of the 40 teams enrolled in the first and second divisions of the Brazilian professional soccer league in 2007. The data obtained were subjected to descriptive analysis to determine absolute and relative frequencies of answers for each one of the questions.

Results

Physicians from 38 (95%) of the 40 teams in the first and second divisions answered the questionnaires and 71.1% reported the occurrence of some type of dental injury during soccer practice, dental fractures (74.1%) and avulsions (59.3%) being the most prevalent ones. Regarding emergency conducts, approximately 50% answered that a successful replantation could be obtained in periods from 6 to 24 h after injury, and 27.8% were not able to answer this question. Regarding mouthguard use, 48.6% of the physicians did not know about mouthguards, and only 21.6% usually recommended their use by the soccer players. Among the physicians who do not recommend the use of mouthguards, 50% justified that it was not necessary. Almost 50% of the medical departments do not have a dentist as part of the health professional staff.

Conclusions

It was possible to conclude that dental injuries are common during professional soccer practice and that there is a lack of information in the medical departments related to the emergency conducts and prevention of dental trauma.

Oral health studies in the 1982 Pelotas (Brazil) birth cohort: methodology and principal results at 15 and 24 years of age

The aim of this study was to describe the methodology and results of oral health studies nested in a birth cohort in Pelotas, Southern Brazil. For the oral health studies a sub-sample (n = 900) was selected from the cohort and dental examinations and interviews were performed at ages 15 (n = 888) and 24 years (n = 720; 81.1%). Data collection included dental outcomes, dental care, oral health behaviors, and use of dental services. Mean DMF-T varied from 5.1 (SD = 3.8) to 5.6 (SD = 4.1) in the study period. The proportion of individuals with at least one filled tooth increased from 51.9% to more than 70%. Individuals who had always been poor used dental services less and had fewer healthy teeth on average than those who had never been poor. Individuals with decreasing or increasing family income trajectories showed intermediate values. An increase was seen in the number of healthy teeth from age 15 to 24 only among those who had never been poor. A history of at least one experience with poverty had a negative impact on oral health in adulthood.

Histologic Response and Tenascin and Fibronectin Expression After Pulp Capping in Pig Primary Teeth With Mineral Trioxide Aggregate or Calcium Hydroxide

Mineral trioxide aggregate produces a lower initial inflammatory response than calcium hydroxide. However, both capping materials produce dentin barriers after seventy days.

Effect of radiotherapy on the hardness and surface roughness of two composite resins

The knowledge about the potential adverse effects of radiotherapy compared to dental composites is a useful information for the clinician's decision regarding adoption of repairs or replacement of dental restorations during oral cancer treatment. This study evaluated the effects of irradiation on microhardness and surface roughness of a microfilled and a packable composite resin. The microfilled composite resin demonstrated significantly lower microhardness and a smoother surface compared to the packable composite resin (p < 0.05). Although irradiation significantly reduced the microhardness for both composite resins (P < 0.05), increasing the x-ray doses did not cause an additional significant decrease in surface hardness (P > 0.05). Meanwhile, irradiation did not produce a significantly rougher surface (P > 0.05), but specimens submitted to abrasion exhibited a significant increase in surface roughness for both composite resins (P < 0.05). It was concluded that while irradiation can adversely affect the hardness of tested composite resins, it does not interfere with surface roughness.

Comparative analysis of two colorimetric assays in dental pulp cell density

AIM

To compare and contrast two colorimetric assays used for the measurement of proliferation using two dental pulp cell types: dental pulp stem cells (DPSC) and human dental pulp fibroblasts (HDPF).

METHODOLOGY

Dental pulp stem cells or HDPF were seeded at 0.25×10(4) cells per well in 96-well plates. Cell proliferation was evaluated after 24-72h. At the end of the experimental period, the sulforhodamine B (SRB) assay or a water-soluble tetrazolium salt (WST-1) assay was performed. Optical densities were determined in a microplate reader (Genius; TECAN). Data were analysed by Student's t-test (comparison between cell types) and one-way anova followed by Tukey test (time-point intervals). Pearson' correlation tests were performed to compare the two assays for each cell line.

RESULTS

Both assays showed that DPSC had higher proliferation rates than HDPF. A positive significant correlation between the two colorimetric assays tested for both cell types DPSC (Pearson's correlation coefficient=0.847; P<0.05) and HDPF (Pearson's correlation coefficient=0.775; P<0.05).

CONCLUSION

Both tests demonstrated similar trends of cell proliferation, and thus are both appropriate for the evaluation of DPSC and HDPF. The choice of assay is therefore one of the practical applications. SRB stained plates can be dried and stored so may have utility in laboratories where data may require review or when access to analytical equipment is limited. WST-1 assays have the benefit of both ease and speed and may have utility in laboratories requiring either high throughput or rapid analyses.

A double-blind randomized clinical trial of two carbamide peroxide tooth bleaching agents: 2-year follow-up

OBJECTIVES

This double-blind randomized clinical trial aimed to evaluate the whitening effect of two at-home tooth bleaching agents and the effect of dietary habits after 2 years. The patients' view about bleaching longevity was also investigated.

METHODS

Ninety-two subjects with mean shade of C1 or darker for the six maxillary anterior teeth were randomized into two groups (n=46) according to the carbamide peroxide (CP) concentration: 10% (CP10) or 16% (CP16). The treatment was performed using the whitening agent in a tray for 2h/day during 3 weeks. Shade evaluations were done with a shade guide and a spectrophotometer at baseline, 1-month, 6-month, 1-year and 2-year post-bleaching.

RESULTS

Eighty-one (88%) of the original 92 subjects enrolled in the study were recalled at 2-year follow-up and, the tooth shade remained significantly lighter than at baseline, in both treatment groups, considering the tooth shade median values (p<0.001) or the color parameters: L*a* (p<0.001) for CP10 and, L*b* for CP16 group (p<0.001). Subjects from CP10 and CP16 reported a consumption of beverage and food stains as high as at 6-month and 1-year recalls and, more than 66% of the participants from each group reported a tooth shade relapse from mild to moderate (p=0.6).

SIGNIFICANCE

At 2-year post-bleaching, tooth shade remained lighter than at baseline for both CP concentrations tested. Tooth shade relapse associated to increasing of a* and b* color parameters were observed for both groups when compared to the end of the treatment (CEP # 37/05).

Factors influencing the microhardness of a microhybrid composite

This study investigated how different photocuring units, exposure times, and ethanol storage affected the depth of cure in a microhybrid composite. Forty composite specimens (each with a depth of 4 mm) were prepared and divided randomly into four groups (n = 10) to receive treatment from a quartz-tungstenhalogen (QTH) curing unit (400 mW/cm2) or a light-emitting-diode (LED) curing unit (180 mW/cm2). The specimens were photocured for either 20 or 40 seconds and stored in the dark for 24 hours at room temperature. Knoop hardness was measured by making three indentations at each depth interval of 1 mm (up to 4 mm) with a 50 g load for 30 seconds. The specimens were stored in ethanol for 24 hours; at that time, hardness was measured again. Data were submitted to three-way ANOVA, Tukey's test, and Student's t-test (p < 0.05). Statistical analysis revealed that hardness was significantly affected by depth, exposure time, and storage in ethanol (p < 0.001). No differences were observed between the curing units tested.

Effect of additional acid etching on bond strength and structural reliability of adhesive systems applied to caries-affected dentin

PURPOSE

To evaluate the effect of additional acid etching on the microtensile bond strength (μTBS) and Weibull modulus (m) of two adhesive systems applied to caries-affected dentin.

MATERIALS AND METHODS

Ninety human molars with coronal carious lesions were sectioned to produce flat coronal surfaces containing caries-affected (CAD) and sound dentin (SD). The teeth were allocated to 6 groups: SB-CT: Control - Single Bond applied according to the manufacturer's instructions; SB+15: Single Bond with additional 35% phosphoric acid etching for 15 s; SB+30: Single Bond with additional etching for 30 s; CF-CT: Control - Clearfil SE Bond applied according to the manufacturer's instructions; CF+15: Clearfil SE Bond with additional 35% phosphoric acid etching for 15 s; CF+30: Clearfil SE Bond with additional etching for 30 s. Composite crowns were incrementally built up. The teeth were sectioned after 24 h in order to produce 2 to 3 slices involving each dentin substrate. The slices were trimmed into hourglass-shaped specimens (n = 30) and tested in tension at a crosshead speed of 1 mm/min. Data were analyzed by three-way ANOVA, Tukey's test (p < 0.05) and Weibull statistics.

RESULTS

The μTBS to CAD was lower than to SD, except for SB+30. The additional etching increased the μTBS to CAD. The μTBS to SD increased with CF, but decreased with SB. CAD produced lower values of m with both adhesive systems. SB resulted in lower m in sound dentin than CF. The additional etching did not affect the m.

CONCLUSION

The additional etching increases the μTBS to CAD, but not enough to reach the μTBS values obtained in SD. The structural reliability of the bond to CAD is not affected by the additional etching.

Nonvital tooth bleaching with halogen light-activated agents: case reports and discussion

Esthetic dentistry has received increased attention in recent years, as people are more aware of the esthetic appearance of their teeth, including alignment and whiteness. This development, combined with a decrease in the incidence and severity of caries, has directed some clinicians toward conservative and non-invasive treatments such as tooth bleaching. A number of methods for nonvital tooth bleaching are described in the literature; these procedures rely on the bleaching agent used, the agent's concentration, product format, and the source of light activation. This article presents two case reports in which dental bleaching with halogen light-activated agents was used to treat a nonvital discolored incisor. The advantages and disadvantages of the technique are discussed.

Resin bond strength to a zirconia-reinforced ceramic after different surface treatments

This study evaluated the microtensile bond strength between a composite resin and a zirconia-reinforced alumina-based glass-infiltrated ceramic after different ceramic surface treatments. Blocks (12 mm x 10 mm x 5 mm3) of a ceramic containing zirconia were fabricated, polished, and divided at random into seven groups, with each group receiving a different surface treatment. The adhesive system and composite resin were applied to the treated ceramic; these composite-ceramic blocks were stored in distilled water (37 degrees C) for seven days. At that point, they were cut along two axes to produce specimens with a cross-sectional area of 1.0 (+/- 0.1) mm2. The specimens (n = 20) were loaded in tension in a universal testing machine with a cross-head speed of 0.5 mm/minute. The microtensile bond strength values were calculated and statistically analyzed using ANOVA and Tukey's test (alpha = 0.05). Among the seven groups, specimens with both a silica coating and a silane coupling agent showed the highest mean microtensile bond strength values. All specimens treated with 9.5% hydrofluoric acid failed during the cutting procedure; among all specimens, the majority of the failures were cohesive. A positive correlation was observed between the fracture type and the microtensile bond strength (r = 0.63).