The implication of integrating pediatric education into a pediatric dentistry course for undergraduate dental students.

Background/purpose: The separation of dentistry and medicine was initiated as a historical root. The purpose of this study was to evaluate the implication of integrating pediatric education into a pediatric dentistry course (so-called the integrated pediatric dentistry course in this study) for undergraduate dental students through students' perspectives. Materials and methods: A total of the 34 fifth-year dental students were invited to fill out the questionnaire for the integrated pediatric dentistry course survey after the class of integrated pediatric dentistry course. Results: Of the 34 dental students, all participated in the survey with a 100% valid response rate. The results showed that most of dental students found this integrated pediatric dentistry course to be helpful in improving their knowledge and clinical skills for pediatric dentistry, and knowledge about pediatrics related to dentistry. However, in comparison, the acquisition of clinical skills was less than that of knowledge for pediatric dentistry. Conclusion: We conclude that the integrated pediatric dentistry course improves dental students' knowledge and clinical skills about pediatric dentistry, and knowledge about pediatrics related to dentistry. Considering the effectiveness of this integrated pediatric dentistry course on students' knowledge and clinical skills, and positive attitude towards pediatric dentistry, this model shows promising for the further use in the dental education.

Correlation between dental professionally topical fluoride application and children's dental use for dental caries under the National Health Insurance system in Taiwan from 2008 to 2021.

Background/purpose: Dental caries is one of the most common oral diseases in children worldwide, especially in Taiwan. This study investigated dental professionally topical fluoride application (PTFA) and children's dental use for dental caries under the National Health Insurance (NHI) system in Taiwan from 2008 to 2021. Materials and methods: The population data and medical records of the NHI system were obtained from the websites of the Ministry of the Interior and the Ministry of Health and Welfare, respectively. The dental PTFA services and dental use indicators for dental caries were analyzed from 2008 to 2021. Results: The number of out-patient visits for dental PTFA services increased from 221,675 in 2008 to 1,078,099 in 2021. The total increase of the out-patient visits was 856,424 with a total increase rate of 386.34%. The one-year increase was 65,879 with a one-year increase rate of 29.72%. Among the 3 age groups of children, their dental use indicators almost presented decreasing trends from 2008 to 2021. Moreover, in general, the dental use indicators showed a negative correlation with the number of the overall out-patient visits for dental PTFA services from 2008 to 2021. Conclusion: In Taiwan, there is a negative correlation between the dental use indicators in NHI system and the number of the overall out-patient visits for dental PTFA services from 2008 to 2021. However, the problem of dental caries in children is still serious and there is still a space for improvement in the oral health education for child caregivers and children.

Concomitant hypo-hyperdontia: A rare entity.

BACKGROUND/PURPOSE: Concomitant hypo-hyperdontia (CHH) is a rare numeric dental anomaly characterized by congenital missing teeth and supernumerary teeth occurring in the same individual. Due to its rarity and sporadicity, the causes of CHH have been completely unknown. Detailed characterization and presentation of more CHH cases not only strengthen clinical diagnosis and treatment for the patients but facilitate the search for etiological factors of the disorder. MATERIALS AND METHODS: From a pedodontic patient population, 21 CHH subjects, with a mean age of 6 years 10 months, were identified and characterized. Dental records and radiographs were scrutinized and analyzed for the distribution and frequencies of involved teeth and concurrent dental anomalies. Through further literature review, 59 CHH cases with supernumeraries in the premaxillary region were retrieved for comparative analyses. RESULTS: The boys were affected twice as often as the girls. While most cases were unrelated and sporadic, two sisters and a pair of identical twins from two unrelated families were presented. Of all cases, only one was of syndromic CHH carrying Duchenne muscular dystrophy. Bimaxillay CHH, with anomalies involving two jaws, occurred more than 4 times as often as maxillary CHH. While all supernumeraries were found in premaxillary region, hypodontia frequently involved lateral incisors and premolars of both jaws. CONCLUSION: As genetic contribution to CHH is strongly suggested by its familial occurrence and syndromic cases, environmental factors seem to play certain roles in modifying disease phenotypes. Judicious use of radiographs during early mixed dentition stage enhances clinical diagnosis and treatment of CHH.

Role of ALK5/Smad2/3 and MEK1/ERK Signaling in Transforming Growth Factor Beta 1-modulated Growth, Collagen Turnover, and Differentiation of Stem Cells from Apical Papilla of Human Tooth.

INTRODUCTION: Transforming growth factor ß1 (TGF-ß1) plays an important role in cell proliferation, matrix formation, and odontogenesis. This study investigated the effects of TGF-ß1 on stem cells from apical papilla (SCAPs) and its signaling by MEK/ERK and Smad2. METHODS: SCAPs were exposed to TGF-ß1 with/without pretreatment and coincubation by SB431542 (an ALK5/Smad 2/3 inhibitor) or U0126 (a MEK/ERK inhibitor). Cell growth was examined by 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide assay or direct counting of viable cells. Collagen content was determined by using the Sircol collagen assay (Biocolor Ltd, Newtownabbey, Northern Ireland). Cell differentiation was evaluated by measuring alkaline phosphatase (ALP) activity. Smad2 and ERK1/2 phosphorylation was analyzed by Western blotting or PathScan phospho-enzyme-linked immunosorbent assay (Cell Signaling Technology Inc, Danvers, MA). RESULTS: TGF-ß1 stimulated the growth and collagen content of cultured SCAPs. TGF-ß1 stimulated ERK1/2 and Smad2 phosphorylation within 60 minutes of exposure. Pretreatment by U0126 and SB431542 effectively prevented the TGF-ß1-induced cell growth and collagen content in SCAPs. TGF-ß1 stimulated ALP activity at lower concentrations (0.1-1 ng/mL) but down-regulated ALP at higher concentrations (>5 ng/mL). U0126 prevented 0.5 ng/mL TGF-ß1-induced ALP activity but showed little effect on 10 ng/mL TGF-ß1-induced decline of ALP in SCAPs. Interestingly, SB431542 attenuated both the stimulatory and inhibitory effects on ALP by TGF-ß1. CONCLUSIONS: TGF-ß1 may affect the proliferation, collagen turnover, and differentiation of SCAPs via differential activation of ALK5/Smad2 and MEK/ERK signaling. These results highlight the future use of TGF-ß1 and SCAP for engineering of pulpal regeneration and apexogenesis.

Erosive potential of soft drinks on human enamel: an in vitro study.

BACKGROUND/PURPOSE: Most soft drinks are acidic in nature. Regular consumption of these drinks may result in dental erosion. The aim of this in vitro study was to evaluate the erosive potential of different soft drinks in Taiwan by a novel multiple erosive method. METHODS: Four commercially available soft drinks in Taiwan were selected for this study. The properties of each product were analyzed to measure their pH, titratable acidity, and ion contents. The erosive potential of the soft drinks was measured based on the amount of loss of human enamel surface following its exposure to the soft drinks tested for different periods (20 minutes, 60 minutes, and 180 minutes). The enamel loss was measured using a confocal laser scanning microscope. RESULTS: The pH values of the soft drinks were below the critical pH value (5.5) for enamel demineralization, and ranged from 2.42 to 3.46. The drink with ingredients of citric acid and ascorbic acid had the highest titratable acidity (33.96 mmol OH(-)/L to pH 5.5 and 71.9 mmol OH(-)/L to pH 7). Exposure to all the soft drinks resulted in loss of human enamel surface (7.28-34.07 µm for 180-minute exposure). The beverage with the highest calcium content had the lowest erosive potential. CONCLUSION: All tested soft drinks were found to be erosive. Soft drinks with high calcium contents have significantly lower erosive potential. Low pH value and high citrate content may cause more surface enamel loss. As the erosive time increased, the titratable acidity to pH 7 may be a predictor of the erosive potential for acidic soft drinks. The erosive potential of the soft drinks may be predicted based on the types of acid content, pH value, titratable acidity, and ion concentration.

Cyclosporine A induces connective tissue growth factor expression in human gingival fibroblasts: suppression by epigallocatechin-3-gallate.

BACKGROUND/PURPOSE: Transforming growth factor-ß (TGF-ß) plays an important role in the pathogenesis of cyclosporine A (CsA)-induced gingival overgrowth (GO). Connective tissue growth factor (CTGF/CCN2) acts as a cofactor with TGF-ß to induce the maximal profibrotic effects of TGF-ß. We investigated the effects of CsA on CCN2 expression in human gingival fibroblasts (HGFs) and the potential chemopreventive agent for CsA-induced GO. METHODS: Western blot analyses were used to examine the signaling pathways of CsA-induced CCN2 expression in HGFs and whether epigallocatechin-3-gallate (EGCG), curcumin, or lovastatin can inhibit CsA-induced CCN2 expression. RESULTS: CsA significantly stimulated CCN2 synthesis in HGFs. This effect can be inhibited by c-Jun NH(2)-terminal kinase (JNK) and Smad3 inhibitors but not by TGF-ß neutralizing antibody and TGF-ß type I receptor inhibitor. Furthermore, EGCG completely blocked CsA-induced CCN2 expression. CONCLUSION: CsA-induced CCN2 protein expression is mediated through JNK and Smad signaling. CsA may contribute to the pathogenesis of GO through upregulation of CCN2 expression in HGFs. EGCG could be an adjuvant for the prevention of CsA-induced GO.

Urethane dimethacrylate induces cytotoxicity and regulates cyclooxygenase-2, hemeoxygenase and carboxylesterase expression in human dental pulp cells.

The toxic effect of urethane dimethacrylate (UDMA), a major dental resin monomer, on human dental pulp is not fully clear. In this study, we investigated the influence of UDMA on the cytotoxicity, cell cycle distribution, apoptosis and related gene expression of dental pulp cells. The role of reactive oxygen species, hemeoxygenase-1 (HO-1) and carboxylesterase (CES) in UDMA cytotoxicity, was evaluated. UDMA induced morphological changes of pulp cells and decreased cell viability by 29-49% at concentrations of 0.1-0.35 mM. UDMA induced G0/G1, G2/M cell cycle arrest and apoptosis. The expression of cdc2, cyclinB1 and cdc25C was inhibited by UDMA. Moreover, UDMA stimulated COX-2, HO-1 and CES2 mRNA expression of pulp cells. The cytotoxicity of UDMA was attenuated by N-acetyl-l-cysteine, catalase and esterase, but was enhanced by Zn-protoporphyrin (HO-1 inhibitor), BNPP (CES inhibitor) and loperamide (CES2 inhibitor). Exposure of UDMA may potentially induce the inflammation and toxicity of dental pulp. These findings are important for understanding the clinical response of human pulp to resin monomers after operative restoration and pulp capping, and also provide clues for improvement of dental materials.

Retrospective survey of biopsied oral lesions in pediatric patients.

BACKGROUND/PURPOSE: Although the general profile of oral biopsies from Asian children has been reported, it was still worth examining whether there were racial and geographic variations in the categories and incidence of pediatric oral lesions. This retrospective study mainly evaluated the categories and incidence of biopsied oral lesions in Taiwanese pediatric patients. METHODS: Biopsy records of all oral lesions from pediatric patients, aged 0-14 years, in the files of the Department of Pathology, National Taiwan University Hospital from 1988 to 2007 were evaluated. The patients were divided into three age groups (0-5, 6-10, and 11-14 years), and the oral lesions were classified into four main categories: inflammatory and reactive, cystic, neoplastic, and other lesions. RESULTS: Of a total of 11,986 biopsied oral lesions, 797 (6.6%) were found in pediatric patients. The most common oral lesions were inflammatory and reactive (45.5%), followed by neoplastic (23.5%), cystic (22.2%), and other (8.8%) lesions. The majority of oral biopsies (47.3%) were taken from patients in the 11-14 years age group. Of the 187 oral neoplastic lesions, 178 (95%) were benign and nine (5%) were malignant, including two premalignant lesions. The maxilla (66 cases) and the mandible (61 cases) were the two most common sites for pediatric neoplastic lesions. The top five oral lesions in pediatric patients were mucous extravasation phenomenon (195 cases), dentigerous cyst (84 cases), odontoma (83 cases), radicular cyst (38 cases), and dental follicle (26 cases). CONCLUSION: The mucous extravasation phenomenon, odontoma, or dentigerous cyst was the most common inflammatory and reactive, neoplastic, or cystic lesion, respectively, in pediatric patients. The relatively high incidence of inflammatory and reactive lesions in pediatric patients implies the importance of stringent oral hygiene in children. Most oral neoplastic lesions in pediatric patients are benign, and malignant oral tumors rarely occur in pediatric patients.

Root fracture of immature permanent incisors--a case report.

This 7-year-old girl experienced pain in her upper central incisors following a fall to the ground. Radiographic examination revealed immature upper central incisors with mid-root oblique and horizontal root fractures. Splinting was performed. When at 3 months, an electric pulp test was positive for both injured teeth, and after 5 months, the fracture lines had disappeared on the radiographs, the splint removed. After 2 years, clinical examination showed normal tooth color and position, with a positive response to the pulp test. Radiographs demonstrated continuous root development, although root canal narrowing was noted at the healed fracture sites.

Dental anomalies in two patients with incontinentia pigmenti.

Incontinentia pigmenti (IP) is a rare X-linked dominant inherited disorder which has a variety of ectodermal aberrations. Skin hyperpigmentation is the most characteristic feature of IP. However, extracutaneous anomalies involving dentition, hair, eyes, and central nervous system are also found. The dental anomalies reported include peg-shaped or malformed teeth, hypodontia, delayed eruption, and impacted tooth. This report describes the dental anomalies in 2 IP patients who had the characteristic features of skin hyperpigmentation. One was a 13-year-old girl who had slender cone-shaped permanent anterior teeth, hypodontia, and delayed eruption of teeth which are characteristic dental anomalies in an IP patient. The other was a 10-year-old girl who only had 2 tulip-shaped maxillary permanent central incisors with shorter tapering roots but no congenital missing teeth or delayed eruption of teeth. Our findings suggest that IP may present a broad variation of dental anomalies individually. However, the characteristic finding of permanent anterior teeth with a longer crown and a shorter root found in both of our IP patients may be worthy of consideration in the differential diagnosis of IP.

Stimulation of glutathione depletion, ROS production and cell cycle arrest of dental pulp cells and gingival epithelial cells by HEMA.

2-Hydroxy-ethyl methacrylate (HEMA) is the major component released from resin-modified glass ionomer cements and dental adhesives. Human tissues mainly affected by HEMA are oral epithelium and dental pulp. We treated human gingival epithelial S-G cells and pulp fibroblasts (HPF) with various concentrations of HEMA, to evaluate its effects on cell growth, cell cycle progression, intracellular glutathione (GSH) level and reactive oxygen species (ROS) production. HEMA-induced growth inhibition in HPF and S-G cells in a dose-dependent manner, which may be partially explained by induction of cell cycle perturbation. G(2)/M phase arrest was noted after exposure of HPF to 5 and 10mm of HEMA, concomitant with glutathione depletion and ROS production. S-phase arrest occurred in S-G cells when treated with 2.5 and 5mm, while at 10mm a sub-G(0)/G(1) peak was noted, indicating the potential induction of apoptosis. GSH depletion was marked in S-G cells only at concentrations of 5 and 10mm, but excessive ROS production was noted at concentration of 1mm and rose with dose increase between 1 and 5mm, then lessened at 10mm. This suggested that the increase of ROS in S-G cells was not mainly caused by GSH depletion. These results helped to define the mechanism of the cytotoxicity caused by HEMA.

A continuous flow system for assessing fluoride release/uptake of fluoride-containing restorative materials.

OBJECTIVES: The aim of this study was to develop a continuous flow system to mimic the kinetics of salivary flow in the mouth and to study the fluoride (F) release/uptake characteristics of both a conventional (Fuji IX) and a resin-modified glass ionomer (Vitremer) in such system. METHODS: Five discs were made for each material. The disc was suspended in a drip chamber sustaining 2 ml of deionized water. The flow rate was controlled at 20 ml/h by an infusion pump. The F release in the drip chamber was assessed at designated time points for up to 6 days. The discs were subjected to 1 min exposures of 0.2% sodium fluoride (NaF); the F re-release was assessed for another 12 h. RESULTS: Following a brief initial burst of F release, the rate decreased rapidly. Vitremer reached a steady low after 8 h, while Fuji IX reached a steady low after 90 min. Cumulative F release was measured from both the effluence and the drip chamber and showed that Vitremer released and took up more F than Fuji IX, both before and after F treatment. Cumulative amounts of fluoride in the drip chamber were much less than that in the effluence. The daily release rate patterns from the two materials were parallel. However, the hourly release rate of Vitremer decreased more gradually than Fuji IX. After sodium fluoride (NaF) treatment, F can be recharged easily and re-released rapidly within 90 min. CONCLUSION: This study indicates that the continuous flow method can be used to assess F release/uptake of the material. This method may represent a closer model to in vivo conditions.