Telomere Attrition Occurs during Ex Vivo Expansion of Human Dental Pulp Stem Cells

We provide a detailed characteristic of stem cells isolated and expanded from the human dental pulp. Dental pulp stem cells express mesenchymal cell markers STRO-1, vimentin, CD29, CD44, CD73, CD90, CD166, and stem cell markers Sox2, nestin, and nucleostemin. They are multipotent as shown by their osteogenic and chondrogenic potential. We measured relative telomere length in 11 dental pulp stem cell lines at different passages by quantitative real-time PCR. Despite their large proliferative capacity, stable viability, phenotype, and genotype over prolonged cultivation, human dental pulp stem cells suffer from progressive telomere shortening over time they replicate in vitro. Relative telomere length (T/S) was inversely correlated with cumulative doubling time. Our findings indicate that excessive ex vivo expansion of adult stem cells should be reduced at minimum to avoid detrimental effects on telomere maintenance and measurement of telomere length should become a standard when certificating the status and replicative age of stem cells prior therapeutic applications

Alimentary fluoride intake in preschool children

<p>Abstract</p> <p>Background</p> <p>The knowledge of background alimentary fluoride intake in preschool children is of utmost importance for introducing optimal and safe caries preventive measures for both individuals and communities. The aim of this study was to assess the daily fluoride intake analyzing duplicate samples of food and beverages. An attempt was made to calculate the daily intake of fluoride from food and swallowed toothpaste.</p> <p>Methods</p> <p>Daily alimentary fluoride intake was measured in a group of 36 children with an average age of 4.75 years and an average weight of 20.69 kg at baseline, by means of a double plate method. This was repeated after six months. Parents recorded their child's diet over 24 hours and collected duplicated portions of food and beverages received by children during this period. Pooled samples of food and beverages were weighed and solid food samples were homogenized. Fluoride was quantitatively extracted from solid food samples by a microdiffusion method using hexadecyldisiloxane and perchloric acid. The content of fluoride extracted from solid food samples, as well as fluoride in beverages, was measured potentiometrically by means of a fluoride ion selective electrode.</p> <p>Results</p> <p>Average daily fluoride intake at baseline was 0.389 (SD 0.054) mg per day. Six months later it was 0.378 (SD 0.084) mg per day which represents 0.020 (SD 0.010) and 0.018 (SD 0.008) mg of fluoride respectively calculated per kg bw/day.</p> <p>When adding the values of unwanted fluoride intake from the toothpaste shown in the literature (0.17-1.21 mg per day) the estimate of the total daily intake of fluoride amounted to 0.554-1.594 mg/day and recalculated to the child's body weight to 0.027-0.077 mg/kg bw/day.</p> <p>Conclusions</p> <p>In the children studied, observed daily fluoride intake reached the threshold for safe fluoride intake. When adding the potential fluoride intake from swallowed toothpaste, alimentary intake reached the optimum range for daily fluoride intake. These results showed that in preschool children, when trying to maximize the benefit of fluoride in caries prevention and to minimize its risk, caution should be exercised when giving advice on the fluoride containing components of child's diet or prescribing fluoride supplements.</p

The Association of Caries Increment Dynamics in Preschool Children with Risk Factors: The 3-Year Prospective Study

This prospective study monitored the dental status, the presence of plaque, and cariogenic microorganism levels of identical children over three years. The aim was to determine the dynamics of caries increment as well as the relationship between risk factors and caries prevalence. A total number of 125 children (72 boys and 53 girls) was included in the study, with an average age of 3.95 &plusmn; 0.06 years at the baseline. During the clinical examination at the nursery schools, the presence of dental plaque was recorded, and saliva samples were collected from the tongue of children for the DentoCult SM test providing easy detection of mutans streptococci from saliva samples. At baseline, 65.6% of the children had no caries, 4% had restored teeth with fillings or crowns or missing teeth due to caries, and 30.4% had at least one untreated caries. The percentages of intact teeth, restored or missing teeth, and untreated caries were 52.8%, 8.8%, 38.4% in the second year and 49.1%, 13.8%, and 31.1% in the third year. The dmft index value was 1.41 &plusmn; 0.24 in the first year, 2.29 &plusmn; 0.30 in the second year, and 2.33 &plusmn; 0.31 in the third year. There was a significant correlation between plaque presence and dt and dmft values (p &lt; 0.05; the statistical analyses were performed using the Kolmogorov-Smirnov test). This 3-year longitudinal study highlighted the importance of examining both the oral hygiene and the level of cariogenic microorganisms when undertaking the evaluation of caries risk evaluation in preschool children

General and oral health status of preterm one-year-old very low and extremely low birthweight infants (a cross - sectional study)

Aims. The aim of the present study was to evaluate the general and oral health status of a group of preterm one-year-old very low (VLBW) and extremely low birthweight (ELBW) infants and make a comparison with full-term one-year-old normal birthweight infants (NBW). Methods. A cross-sectional study was conducted in 102 one-year-old preterm VLBW and ELBW infants, and the data obtained were compared to 87 one-year-old full-term NBW infants. The infants' medical histories were obtained from hospital records and interviews with the mothers. The oral cavities of all infants were examined under the same conditions. The chi-square test, Pearson's chi-square test of independence and Mann-Whitney test were used for the statistical evaluation, with P &lt; 0.05 considered statistically significant. Relative risk (RR) and 95% confidence interval (CI) estimates for variables significantly associated with oral findings were calculated. Results. Both perinatal variables (gestational age, mode of delivery, birthweight, Apgar score, resuscitation, orotracheal intubation and presence of intraoral pathology) and neonatal variables (antibiotic treatment and infections) had a significant association with prematurity, VLBW and ELBW. The one-year-old preterm VLBW and ELBW infants frequently suffered from general diseases, frequently received regular medication and had fewer erupted primary teeth; they also had a higher prevalence of developmental defects of the enamel and deformations of the hard palate. Conclusion. This study confirmed anamnestic, medical and oral differences between one-year-old preterm VLBW and ELBW and full-term NBW infants

The Analysis of Dental Treatment under General Anaesthesia in Medically Compromised and Healthy Children

Dental care under general anaesthesia (GA) is an option when normal treatment cannot be accomplished due to un-cooperation and systemic or cognitive/intellectual disabilities. The purpose of this retrospective cohort study was to analyse the dental treatment under GA in medically compromised and healthy children. The data were collected from the medical records of children who received their dental treatment under GA. The data regarding patient age, sex, general health, and type of treatment were analysed. This clinical trial included 229 study subjects (138 males, 91 females) with an average age of 8.34 (SD 3.78). Counts and relative counts were used for description of qualitative data. The association between the variables was analysed using contingency tables. The significance of the findings was tested by the chi-square test. Most of the children were older pre-school 63 (27.51%) and young school children 102 (44.54%). Medical disability (systemic or intellectual) was diagnosed in 142 children (62.01%); the remaining 87 (37.99%) were healthy children. Dental treatment of primary teeth was more commonly performed in healthy children (65.52%) compared to medically compromised children (58.45%) (p = 0.287). The total number of medically compromised children and the total number of healthy children were both considered to be 100% for the purpose of the following calculations. In terms of permanent dentition, medically compromised children required more extractions and fillings (38.03%, 57.04%) compared to healthy children (14.94%, 17.24%, respectively). The results of this study revealed that dental treatment under GA was more commonly performed in medically compromised children in permanent teeth only in comparison to healthy children. Based on these findings, both health professionals and state authorities should focus more on preventive care in medically compromised children in order to improve their oral health

The Effects of Cryogenic Storage on Human Dental Pulp Stem Cells

Dental pulp stem cells (DPSCs) are a type of easily accessible adult mesenchymal stem cell. Due to their ease of access, DPSCs show great promise in regenerative medicine. However, the tooth extractions from which DPSCs can be obtained are usually performed at a period of life when donors would have no therapeutic need of them. For this reason, it is imperative that successful stem cell storage techniques are employed so that these cells remain viable for future use. Any such techniques must result in high post-thaw stem cell recovery without compromising stemness, proliferation, or multipotency. Uncontrolled-rate freezing is not a technically or financially demanding technique compared to expensive and laborious controlled-rate freezing techniques. This study was aimed at observing the effect of uncontrolled-rate freezing on DPSCs stored for 6 and 12 months. Dimethyl sulfoxide at a concentration of 10% was used as a cryoprotective agent. Various features such as shape, proliferation capacity, phenotype, and multipotency were studied after DPSC thawing. The DPSCs did not compromise their stemness, viability, proliferation, or differentiating capabilities, even after one year of cryopreservation at −80 °C. After thawing, they retained their stemness markers and low-level expression of hematopoietic markers. We observed a size reduction in recovery DPSCs after one year of storage. This observation indicates that DPSCs can be successfully used in potential clinical applications, even after a year of uncontrolled cryopreservation