Nailê Damé-Teixeira

Traumatic dental injury among 12-year-old South Brazilian schoolchildren: prevalence, severity, and risk indicators

An increasing prevalence of traumatic dental injury (TDI) has been reported in the last few decades. The aim of this study was to assess the prevalence and severity of TDI and its association with socio-demographics and physical characteristics in the anterior permanent teeth of 12-year-old Brazilian schoolchildren. A cross-sectional study was carried out in a population-based sample of 1528 subjects attending 33 public and nine private schools (response rate of 83.17%). A single calibrated examiner performed the clinical examinations at the schools and recorded the TDI index (Childrens Dental Health Survey criteria), overjet and lip coverage. Height and weight were measured to calculate the body mass index (BMI). Parents/legal guardians answered a questionnaire containing socio-demographic questions. The relationships among TDI, socio-demographic variables and physical characteristics were assessed by survey Poisson regression models. The prevalence of TDI was 34.79% (mild trauma = 24.37%; severe trauma = 10.43%). Male schoolchildren (RR = 1.41, 95% CI = 1.23-1.61, P = 0.002) and schoolchildren from low socioeconomic status (RR = 1.32, 95% CI = 1.07-1.64, P = 0.021) were more likely to present at least one tooth with TDI, whereas students attending 7th grade (advanced students) were less likely to experience TDI (RR = 0.59, 95% CI = 0.43-0.82, P = 0.012). Regarding the severity analysis, students of mid-high (RR = 1.46, 95% CI = 1.09-1.94, P = 0.022), mid-low (RR = 1.68, 95% CI = 1.01-2.77, P = 0.045) and low (RR = 1.78, 95% CI = 1.11-2.85, P = 0.027) socioeconomic status were more likely to have mild trauma when compared with schoolchildren of high socioeconomic status. No significant association between severe trauma and socioeconomic status was observed. In conclusion, this study showed a high prevalence of TDI in 12-year-old Brazilian schoolchildren. Socio-demographic data and school achievement were associated with TDI.

Traumatic dental injury with treatment needs negatively affects the quality of life of Brazilian schoolchildren

BACKGROUND Traumatic dental injury (TDI) has been considered a significant problem in youth, not only because of its consequences to the craniofacial structures but also for its potential impact on the quality of life of affected individuals. AIM The aim of this study was to investigate the impact of TDI with treatment needs on the oral health-related quality of life (OHRQoL) of South Brazilian schoolchildren. DESIGN A cross-sectional study was performed in Porto Alegre, Brazil, using a multistage probability sampling strategy. Of 1837 eligible 12-year-old schoolchildren attending public and private schools, 1528 were examined. OHRQoL was assessed by the Brazilian version of the Child Perceptions Questionnaire for 11-to 14-year-old children (CPQ11-14) - 16-item short form. Clinical examination was conducted to assess the presence of TDI in permanent incisors (Childrens Dental Health Survey criteria), malocclusion, and dental caries. Parents/legal guardians answered questions on socioeconomic status. Statistical analyses were performed using Poisson regression models. RESULTS The overall CPQ11-14 score was not associated with TDI. In the functional limitations domain, individuals presenting TDIs with treatment needs experienced significantly higher mean CPQ11-14 than individuals with no TDI or without treatment needs (RR = 1.21; 95% CI = 1.05-1.39), after adjusting for malocclusion, dental caries, gender, and socioeconomic status. No other domains were associated with TDI. CONCLUSIONS This study revealed that TDI with treatment needs negatively affects the OHRQoL in this population of 12-year-old schoolchildren and that this impact is related to oral functions.

Association among quality of life, dental caries treatment and intraoral distribution in 12-year-old South Brazilian schoolchildren.

OBJECTIVES To assess the association between dental caries treatment, intraoral distribution and oral health-related quality of life (OHRQoL) of 12-year-old South Brazilian schoolchildren. METHODS This crosssectional survey used a multistage probability sampling strategy to select a representative sample of schoolchildren from Porto Alegre, southern Brazil. Data were collected from September 2009 to December 2010, and 1528 of 1837 eligible schoolchildren attending public and private schools participated. Clinical examination was conducted to assess dental caries experience (DMFT). OHRQoL was assessed by a self-reported 16-item Child Perception Questionnaire (CPQ11–14). Parents/legal guardians answered questions on socio-economic status. Survey negative binomial regression models were used to assess the association between CPQ11–14 scores and caries treatment status (treated/untreated) and intraoral distribution (anterior/posterior). Estimates were controlled for gender and socioeconomic status. RESULTS Compared to schoolchildren without treatment needs, individuals with treated caries presented an improved OHRQoL (overall CPQ11 –14, adjusted RR = 0.90, 95%CI = 0.85–0.96; functional limitations, adjusted RR = 0.86, 95%CI = 0.75–0.99; emotional well-being, adjusted RR = 0.89, 95% CI = 0.80–0.99), whereas those with untreated caries presented a poorer OHRQoL (oral symptoms, adjusted RR = 1.06, 95%CI = 1.02–1.10; emotional well-being, adjusted RR = 1.09, 95%CI = 1.01–1.20). Individuals with caries in anterior teeth experienced greater negative impact on oral symptoms (adjusted RR = 1.11, 95%CI = 1.05–1.18) and social well-being (adjusted RR = 1.30; 95% CI = 1.14–1.47) domains than caries-free students. CONCLUSIONS Treated caries was positively associated with OHRQoL; untreated caries and caries affecting anterior teeth were negatively associated with OHRQoL of 12-year-old Brazilian schoolchildren.

Overweight and obesity are not associated with dental caries among 12-year-old South Brazilian schoolchildren

OBJECTIVES To assess the association between weight status and dental caries among 12-year-old Brazilian schoolchildren. METHODS This cross-sectional study was carried out in Porto Alegre using a multistage probability sampling strategy to draw a representative sample of schoolchildren attending public and private schools. Data on demographics, socioeconomic status, oral hygiene habits, anthropometrics, and dental caries were collected. Overweight and obesity were defined according to WHO categories for BMI (body mass index)-for-age Z-scores. Survey Poisson regression models were used to assess the association between weight status and dental caries. Estimates were adjusted for gender, socioeconomic status, and brushing frequency. Prevalence ratios (PR), rate ratios (RR) and 95% confidence intervals (95% CI) were reported. RESULTS One thousand five hundred and twenty-eight of 1837 eligible schoolchildren were examined. Prevalence of overweight and obesity were 22.15% (95% CI = 20.59-23.72) and 13.61% (95% CI = 11.44-15.78), respectively. Caries experience was observed in 55.23% (95% CI = 45.26-65.19) of children. Schoolchildren presented, on average, 1.39 (95% CI = 1.07-1.71) decayed, missing or filled teeth. No significant differences in caries experience or extent were observed among BMI groups. After adjusting for important cofactors, weight status was not associated with caries prevalence (overweight, PR = 0.99; 95% CI = 0.89-1.10; obese, PR = 1.00; 95% CI = 0.87-1.16) or caries extent (overweight, RR = 0.91; 95% CI = 0.74-1.12; obese, RR = 0.86; 95% CI = 0.72-1.04). CONCLUSIONS Our findings indicate that overweight and obese adolescents should not be regarded as at higher risk of dental caries in this population.

Dental erosion among 12-year-old schoolchildren: a population-based cross-sectional study in South Brazil.

OBJECTIVE To assess the epidemiology and risk indicators for dental erosion among 12-year-old schoolchildren in South Brazil. METHODS A population-based cross-sectional survey was conducted in Porto Alegre, Brazil, using a representative sample of 12-year-old schoolchildren (n = 1,528). Dental erosion was recorded according to the Basic Erosive Wear Examination (BEWE) index. Parents answered questions on socio-economic status, brushing frequency and general health. Schoolchildren answered questions on dietary habits. Anthropometric data were collected. Statistical analysis included logistic and Poisson regression models. RESULTS The prevalence of dental erosion was 15% [95% confidence interval (95% CI): 13.6-16.5], being mainly mild erosion. Boys [odds ratio (OR) = 1.57, 95% CI: 1.17-2.10], private school attendees (OR = 1.45, 95% CI: 1.01-2.06) and schoolchildren reporting the daily consumption of soft drinks (OR = 5.04, 95% CI: 1.17-21.71) were more likely to have at least one tooth with dental erosion. Gender [boys, rate ratio (RR) = 1.66, 95% CI: 1.28-2.17], type of school (private, RR = 1.89, 95% CI: 1.53-2.35), the consumption of soft drinks (sometimes: RR = 5.27, 95% CI: 1.46-19.05; daily: RR = 6.82, 95% CI: 1.39-33.50) and the daily consumption of lemon (RR = 1.49, 95% CI: 1.11-2.00) were significantly associated with the number of affected surfaces. CONCLUSIONS The present study found a moderate prevalence of dental erosion among young schoolchildren, with mild erosion being the most prevalent condition. Socio demographic variables and dietary habits were associated with dental erosion in this population.

Actinomyces spp. gene expression in root caries lesions

Background The studies of the distribution of Actinomyces spp. on carious and non-carious root surfaces have not been able to confirm the association of these bacteria with root caries, although they were extensively implicated as a prime suspect in root caries. Objective The aim of this study was to observe the gene expression of Actinomyces spp. in the microbiota of root surfaces with and without caries. Design The oral biofilms from exposed sound root surface (SRS; n=10) and active root caries (RC; n=30) samples were collected. The total bacterial RNA was extracted, and the mRNA was isolated. Samples with low RNA concentration were pooled, yielding a final sample size of SRS=10 and RC=9. Complementary DNA (cDNA) libraries were prepared and sequenced on an Illumina® HiSeq 2500 system. Sequence reads were mapped to eight Actinomyces genomes. Count data were normalized using DESeq2 to analyse differential gene expression applying the Benjamini-Hochberg correction (false discovery rate [FDR]<0.001). Results Actinomyces spp. had similar numbers of reads (Mann-Whitney U-test; p>0.05), except for Actinomyces OT178 (p=0.001) and Actinomyces gerencseriae (p=0.004), which had higher read counts in the SRS. Genes that code for stress proteins (clp, dnaK, and groEL), enzymes of glycolysis pathways (including enolase and phosphoenolpyruvate carboxykinase), adhesion (Type-2 fimbrial and collagen-binding protein), and cell growth (EF-Tu) were highly – but not differentially (p>0.001) – expressed in both groups. Genes with the most significant upregulation in RC were those coding for hypothetical proteins and uracil DNA glycosylase (p=2.61E-17). The gene with the most significant upregulation in SRS was a peptide ABC transporter substrate-binding protein (log2FC=−6.00, FDR=2.37E-05). Conclusion There were similar levels of Actinomyces gene expression in both sound and carious root biofilms. These bacteria can be commensal in root surface sites but may be cariogenic due to survival mechanisms that allow them to exist in acid environments and to metabolize sugars, saving energy.

Genotypic diversity and virulence traits of Streptococcus mutans isolated from carious dentin after partial caries removal and sealing

The aim of this study was to compare the genotypic diversity and virulence traits of Streptococcus mutans isolated from carious dentin before and after partial dentin caries removal (PDR) and sealing. Carious dentin samples were obtained three months before and after the PDR and cavity sealing. Up to seven isolates of each morphological type of S. mutans were selected and strain identity was confirmed using gtfB primer. Genotyping was performed by arbitrary primer-PCR (AP-PCR). Acidogenesis and acidurance of the genotypes were evaluated as virulence traits. A paired t-test and a Wilcoxon test were used to compare the virulence of genotypes. A total of 48 representative S. mutans isolates were genotyped (31 before and 17 after the sealing). At least one of the genotypes found before the sealing was also found on dentin after the sealing. The number of genotypes found before the sealing ranged from 2 to 3 and after the sealing from 1 to 2 genotypes. No difference was observed in the acidogenesis and acidurance between genotypes isolated before and after the sealing. In conclusion, genotypic diversity of S. mutans decreased after the PDR and sealing, but the virulence traits of S. mutans remained unchangeable.

Eruption Stage of Permanent Molars and Occlusal Caries Activity/Arrest

This study assessed the association between the eruption stage of permanent second molars and occlusal caries activity among 12-year-old schoolchildren from South Brazil. A cross-sectional study was performed in Porto Alegre using a multistage probability sampling strategy to select a representative sample. Clinical examination was conducted to assess the eruption stage of permanent molars, Gingival Bleeding Index, and, after tooth cleaning and drying, caries experience (noncavitated and cavitated lesions, including caries activity assessment). Data were collected on sex, socioeconomic status, mother’s education, brushing frequency, and consumption of soft drinks. Generalized estimating equations were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Overall, 983 schoolchildren with 3,071 second molars were available for analysis. Whereas active caries was observed in 6.6% of fully erupted permanent second molars, caries affected 26.2%, 29.6%, and 18.2% of erupting molars classified as stages 1, 2, and 3, respectively: stage 1, partially erupted occlusal surface; stage 2, fully erupted occlusal surface, <1/2 crown exposed; and stage 3, fully erupted occlusal surface, >1/2 crown exposed. After adjusting for socioeconomic and behavioral variables, partially erupted molars were significantly more likely to present active caries lesions than molars in full occlusion: stage 1, OR = 4.99 (95% CI = 3.38, 7.38); stage 2, OR = 5.18 (95% CI = 3.14, 8.53); stage 3, OR = 3.20 (95% CI = 2.21, 4.64). Similar results were found when clinical variables were included in the adjusted model. In conclusion, most occlusal caries lesions tend to arrest/revert when teeth reach the occlusal plan; however, an important proportion of these lesions remains active and in need of proper management. Children at risk should be targeted with preventive and minimally invasive strategies.

Root Surface Biofilms and Caries

Following gingival recession, which increases with age, the root surface becomes exposed, creating new environments for microbial colonization and biofilm formation. The formation of root surface biofilms is influenced by the availability and composition of saliva and gingival crevicular fluid; they provide components for the conditioning film (acquired root surface pellicle) and also act as a source of nutrients. The early bacterial colonizers of the root surface are similar to those found on the enamel, and Gram-positive species such as Streptococcus sanguinis, S. oralis, S. mitis, and Actinomyces species predominate. The root surface has a lower mineral and higher organic content than enamel, and so is more vulnerable to demineralization. The characterization of the microbiota associated with root surface lesions is still ongoing. Traditional culture-based studies have implicated species such as mutans streptococci, lactobacilli, bifidobacteria, and Actinomyces species, while molecular-based studies have provided evidence for a more complex microbiota with many Gram-negative and anaerobic bacteria being detected in addition to the more conventional cariogenic organisms. Ecological concepts have been applied to explain the microbial etiology of root caries. The acidic environment generated from the fermentation of dietary sugars selects saccharolytic bacteria that can preferentially grow and metabolize under low pH conditions, and then proteolytic Gram-negative species are selected when the dentin is exposed and collagen and other proteins become accessible to be catabolized. These species act in concert to degrade the inorganic and organic components of the dental tissues.

Gene expression of bacterial collagenolytic proteases in root caries

ABSTRACT Objective: It is unknown whether bacteria play a role in the collagen matrix degradation that occurs during caries progression. Our aim was to characterize the expression level of genes involved in bacterial collagenolytic proteases in root biofilms with and without caries. Method: we collected samples from active cavitated root caries lesions (RC, n = 30) and from sound root surfaces (SRS, n = 10). Total microbial RNA was isolated and cDNA sequenced on the Illumina Hi-Seq2500. Reads were mapped to 162 oral bacterial reference genomes. Genes encoding putative bacterial collagenolytic proteases were identified. Normalization and differential expression analysis was performed on all metatranscriptomes (FDR<10-3). Result: Genes encoding collagenases were identified in 113 bacterial species the majority were peptidase U32. In RC, Streptococcus mutans and Veillonella parvula expressed the most collagenases. Organisms that overexpressed collagenolytic protease genes in RC (Log2FoldChange>8) but none in SRS were Pseudoramibacter alactolyticus [HMPREF0721_RS02020; HMPREF0721_RS04640], Scardovia inopinata [SCIP_RS02440] and Olsenella uli DSM7084 [OLSU_RS02990]. Conclusion: Our findings suggest that the U32 proteases may be related to carious dentine. The contribution of a small number of species to dentine degradation should be further investigated. These proteases may have potential in future biotechnological and medical applications, serving as targets for the development of therapeutic agents.