Single-walled carbon nanotubes functionalized with sodium hyaluronate enhance bone mineralization.

The aim of this study was to evaluate the effects of sodium hyaluronate (HY), single-walled carbon nanotubes (SWCNTs) and HY-functionalized SWCNTs (HY-SWCNTs) on the behavior of primary osteoblasts, as well as to investigate the deposition of inorganic crystals on titanium surfaces coated with these biocomposites. Primary osteoblasts were obtained from the calvarial bones of male newborn Wistar rats (5 rats for each cell extraction). We assessed cell viability using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay and by double-staining with propidium iodide and Hoechst. We also assessed the formation of mineralized bone nodules by von Kossa staining, the mRNA expression of bone repair proteins, and the deposition of inorganic crystals on titanium surfaces coated with HY, SWCNTs, or HY-SWCNTs. The results showed that treatment with these biocomposites did not alter the viability of primary osteoblasts. Furthermore, deposition of mineralized bone nodules was significantly increased by cells treated with HY and HY-SWCNTs. This can be partly explained by an increase in the mRNA expression of type I and III collagen, osteocalcin, and bone morphogenetic proteins 2 and 4. Additionally, the titanium surface treated with HY-SWCNTs showed a significant increase in the deposition of inorganic crystals. Thus, our data indicate that HY, SWCNTs, and HY-SWCNTs are potentially useful for the development of new strategies for bone tissue engineering.

Single-walled carbon nanotubes functionalized with sodium hyaluronate enhance bone mineralization

The aim of this study was to evaluate the effects of sodium hyaluronate (HY), single-walled carbon nanotubes (SWCNTs) and HY-functionalized SWCNTs (HY-SWCNTs) on the behavior of primary osteoblasts, as well as to investigate the deposition of inorganic crystals on titanium surfaces coated with these biocomposites. Primary osteoblasts were obtained from the calvarial bones of male newborn Wistar rats (5 rats for each cell extraction). We assessed cell viability using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay and by double-staining with propidium iodide and Hoechst. We also assessed the formation of mineralized bone nodules by von Kossa staining, the mRNA expression of bone repair proteins, and the deposition of inorganic crystals on titanium surfaces coated with HY, SWCNTs, or HY-SWCNTs. The results showed that treatment with these biocomposites did not alter the viability of primary osteoblasts. Furthermore, deposition of mineralized bone nodules was significantly increased by cells treated with HY and HY-SWCNTs. This can be partly explained by an increase in the mRNA expression of type I and III collagen, osteocalcin, and bone morphogenetic proteins 2 and 4. Additionally, the titanium surface treated with HY-SWCNTs showed a significant increase in the deposition of inorganic crystals. Thus, our data indicate that HY, SWCNTs, and HY-SWCNTs are potentially useful for the development of new strategies for bone tissue engineering.

Malocclusion in preschool children: prevalence and determinant factors.

PURPOSE: To evaluate the prevalence of malocclusion and associated factors in the primary dentition of preschoolers in the city of Diamantina, Brazil. METHODS: A cross-sectional study was carried out with 381 children aged 3-5 years treated at the 10 basic health care units in the city during immunisation campaigns. The dependent variables (presence of malocclusion, open bite, crossbite and crowding) were evaluated through a clinical oral exam. The independent variables (gender, age, health problems, breastfeeding, bottle feeding, harmful oral habits, mother's schooling, household income and number of children in the home) were collected through interviews. Statistical analysis involved descriptive analysis, Chi square test and Poisson regression. RESULTS: The prevalence of malocclusion was 32.5%. Open bite was the most frequent type of malocclusion. Children with a history of bottle feeding (PR 1.74; 95% CI 1.24-2.44) and those with harmful oral habits (PR 1.49; 95% CI 1.23-1.99) had greater prevalence rates of malocclusion. Greater prevalence rates of open bite were also found in children with a history of bottle feeding (PR 5.00; 95% CI 1.99-12.5) and those with harmful oral habits (PR 2.90; 95% CI 1.59-5.29), whereas greater prevalence rates of crossbite were found in boys (PR 1.79; 95% CI 1.10-2.91) and were associated with mother's schooling (PR 1.91; 95% CI 1.20-3.06). CONCLUSION: A history of bottle feeding and the presence of harmful oral habits were identified as determinants for the occurrence of malocclusion in preschoolers.

Mothers' reports on systemic signs and symptoms associated with teething.

PURPOSE: The purpose of this study was to compare mothers' actual observations of signs and symptoms associated with the eruption of primary incisors in their infants with their own recollections of the same period after eruption was completed. METHODS: A comparative study was carried out with 45 non-institutionalized infants and their mothers. Oral clinical exams were performed daily for detection of tooth eruption. The mothers were also interviewed daily about signs and symptoms they thought were associated with teething in the previous 24 hours. One week after the data collection was done, the mothers answered the same questionnaire. Descriptive analysis and the McNemar test (P<.05) were performed. RESULTS: Statistically significant differences were found between the prospective and retrospective studies. Increased salivation (P<.04) and runny nose (P<.001) were reported less often and fever was reported more often (P<.001) in the retrospective evaluation. CONCLUSIONS: Mothers reported similar manifestations of sleep disturbance, diarrhea, loss of appetite, and irritability in the prospective and retrospective studies. Increased salivation and runny nose were more frequently reported in the prospective study, whereas fever was reported 5 times more often in the retrospective study.

Carbon nanotubes: directions and perspectives in oral regenerative medicine.

One of the main goals of bone tissue engineering is to identify and develop new biomaterials and scaffolds for structural support and controlled cell growth, which allow for formation or replacement of bone tissue. Recently, carbon nanotubes (CNT) have emerged as a potential candidate for bone tissue engineering. CNT present remarkable mechanical, thermal, and electrical properties with easy functionalization capability and biocompatibility. In oral regenerative medicine, bone reconstruction is an essential requirement for functional rehabilitation of the stomatognathic system. Autologous bone still represents the gold standard graft material for bone reconstruction. However, the small amounts of bone available in donor regions, together with the high costs of surgeries, are critical aspects that hinder the selection of this procedure. Thus, CNT alone or combined with biopolymers have promise to be used as novel potential biomaterials for the restoration of bone defects. Indeed, recent evidence demonstrates CNT to be a feasible material that can increase the formation of bone in tooth sockets of rats. The purpose of this review is to summarize the recent developments in bone repair/regeneration with CNT or CNT-based composites. We further provide an overview of bone tissue engineering and current applications of biomaterials, especially of CNT, to enhance bone regeneration.

Impact of early childhood caries on the oral health-related quality of life of preschool children and their parents.

The aim of the present population study was to evaluate the impact of early childhood caries (ECC) on the oral health-related quality of life (OHRQoL) of preschool children and their parents/caregivers. A random sample of 638 children (aged 2-5 years) underwent a clinical oral examination to assess ECC, and their parents were invited to answer two questionnaires: one on the OHRQoL of the child, the Early Childhood Oral Health Impact Scale, and another on the characteristics and sociodemographic conditions of the child. Descriptive analysis, χ(2) test, Mann-Whitney test, Kruskal-Wallis test, and hierarchically adjusted Poisson regression models were used. The prevalence of ECC was 52.2%. The number of teeth with decay ranged from 1 (n = 42; 6.6%) to 20 (n = 5; 0.8%), averaging 2.86 (SD = 4.04). There was a significant difference between the severity of ECC and OHRQoL in terms of the impact on both child and family (p < 0.001). An increase in the severity of ECC resulted in an increased negative impact on the quality of life of the child (rate ratio, RR = 5.32; 95% confidence interval, CI: 3.67-7.71). Greater age of the mother had a positive impact on the OHRQoL of preschool children (RR = 0.72; 95% CI: 0.54-0.97). Increased age resulted in an increased negative impact on the quality of life of the child (RR = 2.97; 95% CI: 1.61-5.47). ECC has a negative impact on the OHRQoL of children aged 2-5 years and their parents. Mothers aged 30 or older reported better OHRQoL, independent of the presence of ECC and the age of the child.

Untreated dental caries: impact on quality of life of children of low socioeconomic status.

PURPOSE: This study's purpose was to evaluate the impact of untreated dental caries on the oral health-related quality of life (OHRQoL) of children of low socioeconomic status. METHODS: One hundred twelve impoverished 8- to 10-year-olds from a city in southeastern Brazil were selected. OHRQoL was measured using the Child Perceptions Questionnaire (CPQ8-10; total and subscale scores) and its global question on oral health. The clinical examination recorded the prevalence of untreated dental caries (corresponding to a non-zero D or d component in the DMFT or dmft indices). The children were categorized as without untreated dental caries=0 or with untreated dental caries ≥1. Malocclusions and dental trauma were determined using the Dental Aesthetic Index and Andreasen and Andreasen (1994) classification, respectively. Descriptive analysis, Mann-Whitney, chi-square test, and hierarchically adjusted Poisson regression models were employed. RESULTS: Eighty-four children (75%) had 1 or more carious teeth. The relative risk of having a negative perception of oral health was greater among the children with untreated dental caries (RR-1:41; 95% confidence interval=1.13-1.75), regardless of gender or malocclusion. CONCLUSION: Eight- to 10-year-olds with untreated dental caries have a greater relative risk of having a negative perception of oral health status than those without dental caries.

Malocclusion: social, functional and emotional influence on children.

OBJECTIVES: To determine the association between types of malocclusion and quality of life in children between 8-10 years of age and establish correlations between the severity of the malocclusion and particular bio-psychosocial variables. STUDY DESIGN: The sample was made up of 102 schoolchildren aged 8-10 years. Clinical exams were performed using the criteria of the Dental Aesthetic Index (DAI) to determine the presence and severity of malocclusions. The impact on quality of life was assessed using the Child Perceptions Questionnaire (CPQ8-10). Statistical analysis involved the chi-square test, Fisher's exact test and Spearman's correlation analysis. RESULTS: Malocclusions affected 61% of the children examined. There was a positive correlation between total CPQ8-10 and DAI scores (P = 0.034). The following types of malocclusion had a significant effect on the quality of life of the children: upper anterior irregularity > or = 2 mm, anterior open bite > or = 2 mm and diastema > or = 2 mm. Children with malocclusion experienced a greater negative impact on quality of life in comparison to those without malocclusion. CONCLUSIONS: Malocclusions had a negative influence over the quality of life of children between 8-10 years of age. More severe malocclusions had a greater impact with regard to social, emotional and functional aspects.