Radiation caries is a complication of radiotherapy characterized by enamel erosion and dentin exposure. The mechanisms of characteristic radiation caries formation are not well-understood. The aim of this study was to evaluate the direct radiation-induced effects on dental hard tissue and investigate their role in the formation of radiation caries. Sixty non-carious third molars were divided into three groups (n = 20), which would be exposed to 0 Gy, 30 Gy, and 60 Gy radiation, respectively. After radiation, microhardness and elastic modulus were measured at four depths by means of a Vickers microhardness tester and atomic force microscopy (AFM). The microstructure was observed by scanning electron microscopy (SEM). X-ray diffraction and Raman microspectroscopy were used to determine crystal properties and protein/mineral (2931/960 cm− 1) ratios. A statistically significant decrease in microhardness and elastic modulus values 50 μm from the dentino-enamel junction (DEJ) in enamel was revealed in the 30-Gy and 60-Gy groups. With the increasing dose, destruction of interprismatic substance and fissures at the DEJ-adjacent region were found. A greater reduction of crystallinity was revealed in enamel compared with dentin. Raman spectroscopic analysis showed a slight increase of the protein/mineral ratio for enamel following accumulated radiation, while the protein/mineral ratio for dentin was decreased. Radiation could directly alter the mechanical properties, micro-morphology, crystal properties, and chemical composition of dental hard tissue. The early destruction of DEJ-adjacent enamel, combined with decreased crystallinity of enamel under radiation exposure, may be related to the formation of characteristic radiation caries.

: Both X-linked hypohidrotic ectodermal dysplasia (XLHED) and non-syndromic tooth agenesis (NSTA) result in symptoms of congenital tooth loss. This study investigated genetic causes in two families with XLHED and four families with NSTA. We screened for mutations of WNT10A, EDA, EDAR, EDARADD, PAX9, MSX1, AXIN2, LRP6, and WNT10B through Sanger sequencing. Whole exome sequencing was performed for the proband of NSTA Family 4. Novel mutation c.1051G>T (p.Val351Phe) and the known mutation c.467G>A (p.Arg156His) of Ectodysplasin A (EDA) were identified in families with XLHED. Novel EDA receptor (EDAR) mutation c.73C>T (p.Arg25*), known EDA mutation c.491A>C (p.Glu164Ala), and known Wnt family member 10A (WNT10A) mutations c.511C>T (p.Arg171Cys) and c.742C>T (p.Arg248*) were identified in families with NSTA. The novel EDA and EDAR mutations were predicted as being pathogenic through bioinformatics analyses and structural modeling. Two variants of WNT10A, c.374G>A (p.Arg125Lys) and c.125A>G (p.Asn42Ser), were found in patients with NSTA. The two WNT10A variants were predicted to affect the splicing of message RNA, but minigene experiments showed normal splicing of mutated minigenes. This study uncovered the genetic foundations with respect to six families with XLHED or NSTA. We identified six mutations, of which two were novel mutations of EDA and EDAR. This is the first report of a nonsense EDAR mutation leading to NSTA.

Hypohidrotic ectodermal dysplasia (HED) is characterized by abnormal development of the teeth, hair, and sweat glands. Ectodysplasin A (EDA), Ectodysplasin A receptor (EDAR), and EDAR-associated death domain (EDARADD) are candidate genes for HED, but the relationship between WNT10A and HED has not yet been validated. In this study, we included patients who presented at least two of the three ectodermal dysplasia features. The four genes were analyzed in seven HED patients by PCR and Sanger sequencing. Five EDA and one EDAR heterozygous mutations were identified in families 1–6. Two WNT10A heterozygous mutations were identified in family 7 as a compound heterozygote. c.662G>A (p.Gly221Asp) in EDA and c.354T>G (p.Tyr118*) in WNT10A are novel mutations. Bioinformatics analyses results confirmed the pathogenicity of the two novel mutations. In family 7, we also identified two single-nucleotide polymorphisms (SNPs) that were predicted to affect the splicing of EDAR. Analysis of the patient’s total RNA revealed normal splicing of EDAR. This ascertained that the compound heterozygous WNT10A mutations are the genetic defects that led to the onset of HED. Our data revealed the genetic basis of seven HED patients and expended the mutational spectrum. Interestingly, we confirmed WNT10A as a candidate gene of HED and we propose WNT10A to be tested in EDA-negative HED patients.

Periodontitis is a highly prevalent oral disease characterized by irreversible bone resorption and tooth loss. The proliferation, migration and osteogenic differentiation of periodontal ligament stem cell (PDLSC) are crucial to the regeneration of periodontal bone defects. There is increasing evidence that small extracellular vesicle (sEV) derived from pulp stem cell, including human exfoliated deciduous teeth stem cell (SHED) and human dental pulp stem cell (DPSC), is a potential mediator for bone tissue regeneration. However, which one is more suitable for periodontal bone formation still remains to be studied. In this study, NTA and BCA were performed to compare the productivity of sEV derived from SHED (SHED-sEV) and sEV derived from DPSC (DPSC-sEV). CCK-8, transwell assay, alkaline phosphatase staining and activity assay, alizarin red staining, qRT-PCR, and western blotting were conducted to detect the proliferation, migration, and osteogenesis of PDLSCs coculturing with SHED-sEV or DPSC-sEV. The secretory efficiency of SHED-sEV was much higher than that of DPSC-sEV. The cellular uptake of sEVs could promote the proliferation, migration and osteogenesis of DPLSCs. Compared with DPSC-sEV, SHED-sEV showed better ability in such promotion. SHED-sEV showed higher productivity and better osteogenic induction ability than DPSC-sEV. Thus, SHED-sEV may be a more promising candidate for periodontal bone regeneration.

The dental health of preschool children with congenital heart disease (CHD) is usually poor, which may contribute to the development of infective endocarditis (IE). Primary care physicians play an important role in providing access to preventive dental services, particularly for preschool children. The object of this study was to provide epidemiologic evidence for the impact of primary care physicians’ (PCP’s) counseling role on early childhood caries in children with CHD in Guangzhou, China, which might guide future caries prevention to decrease the risk of IE in children with CHD. A hospital-based, case-control study was performed, which contained 100 children with newly diagnosed early childhood caries and 100 matched (sex and age) children without dental caries. All of the subjects were diagnosed with CHD at birth and recruited from Guangdong Cardiovascular Institute from 2012 through 2013. A conditional multivariate logistic-regression model was used to assess the associations between PCPs’ role and early childhood caries with a significance level of 5%. Our findings revealed that mother’s education level (OR = 0.36, CL = 0.14–0.92) and knowledge, being educated on the relationship between CHD and infective endocarditis (OR = 0.48, CL = 0.25–0.94) and the impact of oral health on infective endocarditis (OR = 0.37, CL = 0.18–0.79) by the PCP were associated with early childhood caries. PCPs played an important role in preventing early childhood caries among preschool children with CHD in Guangzhou, China.

Supernumerary tooth-derived pulp stem cells (SNTSCs) hold promise for endodontic regeneration, yet little is known about the similarities and diversities of SNTSCs relative to other dental-derived mesenchymal stem cells. Herein, we compare the biological characteristics of SNTSCs with dental pulp stem cells (DPSCs) and stem cells from human exfoliated deciduous teeth (SHED). Cell proliferation, migration, and odontogenic differentiation potential, as well as viability and aging-related phenotype after long-term storage, were evaluated. Additionally, gene expressions during induced odontogenic differentiation were profiled by transcriptome sequencing. Our findings indicated that the SNTSCs outperformed the DPSCs but were inferior to the SHED in cell proliferation. The SNTSCs exhibited comparable migratory capacity to the SHED and surpassed the DPSCs. Of particular interest, the odontogenic differentiation potential followed the pattern of SHED > SNTSCs > DPSCs. After two years of storage, the SNTSCs showed weakness in resistance to apoptosis induced by lipopolysaccharide, whereas difference between the SNTSCs and SHED in stemness and senescence was not obvious. Transcriptome analysis revealed that upregulated genes in the SNTSCs were particularly enriched in inflammatory signaling pathways compared to both the DPSCs and SHED. Collectively, SNTSCs share many satisfactory features in proliferation and differentiation with SHED, which may serve as a promising alternative cell source for endodontic regeneration.