A novel WNT10A variant impairs the homeostasis of alveolar bone mesenchymal stem cells.

OBJECTIVES: To explore the influence of a novel WNT10A variant on bone mineral density, proliferation, and osteogenic differentiation capacities of alveolar bone mesenchymal stem cells in humans. SUBJECTS AND METHODS: Whole-exome sequencing and Sanger sequencing were utilized to detect gene variants in a family with non-syndromic tooth agenesis (NSTA). The panoramic mandibular index was calculated on the proband with WNT10A variant and normal controls to evaluate bone mineral density. Alveolar bone mesenchymal stem cells from the proband with a novel WNT10A variant and normal controls were isolated and cultured, then proliferation and osteogenic differentiation capacities were evaluated and compared. RESULTS: We identified a novel WNT10A pathogenic missense variant (c.353A > G/p. Tyr118Cys) in a family with NSTA. The panoramic mandibular index of the proband implied a reduction in bone mineral density. Moreover, the proliferation and osteogenic differentiation capacities of alveolar bone mesenchymal stem cells from the proband with WNT10A Tyr118Cys variant were significantly decreased. CONCLUSIONS: Our findings broaden the spectrum of WNT10A variants in patients with non-syndromic oligodontia, suggest an association between WNT10A and the proliferation and osteogenic differentiation of alveolar bone mesenchymal stem cells, and demonstrate that WNT10A is involved in maintaining jaw bone homeostasis.

BMPR2 Variants Underlie Nonsyndromic Oligodontia.

Oligodontia manifests as a congenital reduction in the number of permanent teeth. Despite the major efforts that have been made, the genetic etiology of oligodontia remains largely unknown. Bone morphogenetic protein receptor type 2 (BMPR2) variants have been associated with pulmonary arterial hypertension (PAH). However, the genetic significance of BMPR2 in oligodontia has not been previously reported. In the present study, we identified a novel heterozygous variant (c.814C > T; p.Arg272Cys) of BMPR2 in a family with nonsyndromic oligodontia by performing whole-exome sequencing. In addition, we identified two additional heterozygous variants (c.1042G > A; p.Val348Ile and c.1429A > G; p.Lys477Glu) among a cohort of 130 unrelated individuals with nonsyndromic oligodontia by performing Sanger sequencing. Functional analysis demonstrated that the activities of phospho-SMAD1/5/8 were significantly inhibited in BMPR2-knockout 293T cells transfected with variant-expressing plasmids, and were significantly lower in BMPR2 heterozygosity simulation groups than in the wild-type group, indicating that haploinsufficiency may represent the genetic mechanism. RNAscope in situ hybridization revealed that BMPR2 transcripts were highly expressed in the dental papilla and adjacent inner enamel epithelium in mice tooth germs, suggesting that BMPR2 may play important roles in tooth development. Our findings broaden the genetic spectrum of oligodontia and provide clinical and genetic evidence supporting the importance of BMPR2 in nonsyndromic oligodontia.

A Novel CDH1 Variant Identified in a Chinese Family with Blepharocheilodontic Syndrome.

The goal of the current study was to identify the pathogenic gene variant in a Chinese family with Blepharocheilodontic (BCD) syndrome. Whole-exome sequencing (WES) and Sanger sequencing were used to identify the pathogenic gene variant. The harmfulness of the variant was predicted by bioinformatics. We identified a novel heterozygous missense variant c.1198G>A (p.Asp400Asn) in the CDH1 gene in the proband and his mother with BCD syndrome. The sequencing results of three healthy individuals in this family are wild type. This result is consistent with familial co-segregation. According to ReVe, REVEL, CADD, gnomAD, dbSNP, and the classification of pathogenic variants with the standards of the 2015 American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG), c.1198G>A (p.Asp400Asn) is predicted to be a likely pathogenic. We observed that variant c.1198G>A (p.Asp400Asn) was located in the extracellular cadherin-type repeats in CDH1. Amino acid sequence alignment of the CDH1 protein among multiple species showed that Asp400 was highly evolutionarily conserved. The conformational analysis showed that this variant might cause structural damage to the CDH1 protein. Phenotypic analysis revealed unique dental phenotypes in patients with BCD syndrome, such as oligodontia, conical-shaped teeth, and notching of the incisal edges. Our results broaden the variation spectrum of BCD syndrome and phenotype spectrum of CDH1, which can help with the clinical diagnosis, treatment, and genetic counseling in relation to BCD syndrome.

Dose Dependence Effect in Biallelic WNT10A Variant-Associated Tooth Agenesis Phenotype.

The goal of this study was to identify the pathogenic gene variants in patients with odonto-onycho-dermal dysplasia syndrome (OODD) or nonsyndromic tooth agenesis. Four unrelated individuals with tooth agenesis and their available family members were recruited. Peripheral blood was collected from four probands and five family members. Whole-exome sequencing (WES) and Sanger sequencing were used to identify the pathogenic gene variants. The harmfulness of these variations was predicted by bioinformatics. We identified four biallelic variants of the WNT10A gene in four patients, respectively: the proband#660: c.1176C > A (p.Cys392*) and c.812G > A (p.Cys271Tyr); the proband#681: c.637G > A (p.Gly213Ser) and c.985C > T (p.Arg329*); the proband#829: c.511C > T (p.Arg171Cys) and c.637G > A (p.Gly213Ser); and the proband#338: c.926A> G (p.Gln309Arg) and c.511C > T (p.Arg171Cys). Among them, two variants (c.812G > A; p.Cys271Tyr and c.985C > T; p.Arg329*) were previously unreported. Bioinformatics analysis showed that the pathogenicity of these six variants was different. Tertiary structure analysis showed that these variants were predicted to cause structural damage to the WNT10A protein. Genotype−phenotype analysis showed that the biallelic variants with more harmful effects, such as nonsense variants, caused OODD syndrome (#660 Ⅱ-1) or severe nonsyndromic tooth agenesis (NSTA) (#681 Ⅱ-1); the biallelic variants with less harmful effects, such as missense variants, caused a mild form of NSTA (#829 Ⅱ-2 and #338 Ⅱ-1). Individuals with a heterozygous variant presented a mild form of NSTA or a normal state. Our results further suggest the existence of the dose dependence of WNT10A pathogenicity on the tooth agenesis pattern, which broadens the variation spectrum and phenotype spectrum of WNT10A and could help with clinical diagnosis, treatment, and genetic counseling.

Comparison of indirect pulp treatment and iRoot BP Plus pulpotomy in primary teeth with extremely deep caries: a prospective randomized trial.

OBJECTIVES: The purpose of this randomized controlled trial was to compare the 24-month success rates of indirect pulp treatment (IPT) and iRoot BP Plus pulpotomy of primary molars with extremely deep caries. MATERIALS AND METHODS: Generally healthy children aged 3-7 years requiring general anesthesia for treating primary molars with extremely deep caries or reversible pulpitis were recruited. Patients with systemic disease, mental health problems, or manifestations of irreversible pulpitis were excluded. In total, 175 molars were randomized and blinded for either IPT (n = 87) or iRoot BP Plus pulpotomy (n = 88). All teeth were restored with stainless steel crowns and evaluated after 6, 12, 18, and 24 months by two blinded calibrated investigators. Kaplan-Meier survival curves were used to compare the survival rates between the groups. The correlations between success rate and patient characteristics were explored with the Cox proportional hazards model. RESULTS: A total of 168 primary molars in 67 patients (average age: 3.83 years) were evaluated. The cumulative survival probability at 24 months was not significantly different between the IPT (93.8%) and pulpotomy (97.7%) groups (P = 0.238). IPT treatment success was significantly associated with age (odds ratio = 2.347; 95% CI: 1.068-5.156; P = 0.034) and preoperative sensitivity (odds ratio = 9.742; 95% CI: 1.079-87.970; P = 0.043). CONCLUSIONS: The 24-month success rates of IPT and iRoot BP Plus pulpotomy performed in primary molars with extremely deep caries were not significantly different. Increasing age and preoperative sensitivity were found to be associated with the cumulative survival probability in IPT-treated primary molars with extremely deep caries. Primary teeth with extremely deep carious lesions without signs of irreversible pulpitis can be treated successfully by either indirect pulp capping or iRoot BP Plus pulpotomy. TRIAL REGISTRATION: ChiCTR2000032462.

[Degradation evaluation and success of pulpectomy with a modified primary root canal filling in primary molars].

OBJECTIVE: To compare clinical and radiographic success rates of a modified primary root canal filling (ingredients: zinc oxide-eugenol, iodoform and calcium hydroxide, MPRCF) vs. zinc oxide-eugenol cement (ZOE) and calcium hydroxide/iodoform paste (Vitapex) in pulpectomized primary molars at the end of 6 and 12 months, and to evaluate the degradation of materials in the root canals and in apical area. METHODS: In the study, 160 primary molars from 155 children (the average age: 5.88±1.27 years) that met the inclusion criteria were allocated to one of the three materials via block randomization. A two-visit pulpectomy was performed by an investigator. The clinical and radiographic diagnoses were blindly assessed by other two investigators. RESULTS: At the end of 6 and 12 months, the ZOE and MPRCF success rates were 100% both in clinical and radiographic evaluation. The Vitapex group showed the clinical success of 100% at the end of 6 months and 94.5% at the end of 12 months. Radiographic evaluation for the Vitapex group showed 80.4% success at the end of 6 months and 60.7% at the end of 12 months. No statistically significant differences were noted at the end of 6 months in the three groups both in clinical and radiographic evaluation. The success rates in clinical and radiographic evaluation at the end of 12 months for ZOE and MPRCF groups were not significantly different, and better than those for Vitapex group with statistically significant difference. The completely resorb rate of excess extruded extraradicularly were 14.3%, 100% and 71.4% for ZOE, Vitapex and MPRCF at the end of 12 months. The rates of resorption of material at the same rate of the root were 5.8%, 7.2% and 40.9% for ZOE, Vitapex and MPRCF at the end of 12 months. CONCLUSION: MPRCF, a mixture of zinc oxide eugenol and iodoform with calcium hydroxide can be used as a root canal filling material in primary teeth, taking account of the success rate and resorbing at a similar rate with the roots of the primary teeth.

Effects of zinc oxide-eugenol and calcium hydroxide/ iodoform on delaying root resorption in primary molars without successors.

The purpose of this study was to compare the effects of zinc oxide-eugenol (ZOE) and calcium hydroxide/iodoform paste (Vitapex), as root canal filling materials in pulpectomy, on delaying the root resorption of primary molars without permanent successors. Animal models without permanent successors were surgically established in beagle dogs. Root resorption was observed via periapical radiographs. The onset of root resorption of primary mandibular molars without successors occurred later (p<0.05) than physiologic resorption. ZOE pulpectomy clearly delayed the root resorption of primary molars without permanent successors (p<0.05), whereas resorption of primary molars with Vitapex pulpectomy started at almost the same time as physiologic resorption. Compared with Vitapex, ZOE was a more effective root canal filling material in delaying the root resorption of primary molars.

Cyclin D1 polymorphism and oral cancer: a meta-analysis.

Cyclin D1 (CCND1) plays a critical role in the G1 to S-phase cell cycle transition. Data on the association between the CCND1 A870G polymorphism and oral cancer are conflicting. To assess the relationship between the CCND1 A870G genotype and the risk of developing oral cancer, we performed a meta-analysis. We searched PubMed to December 1, 2011, for studies on this topic that had been published in the English. For each study, we calculated odds ratios (ORs) and 95 % confidence intervals (CIs), assuming the frequency of allele comparison, homozygote comparison, recessive and dominant genetic models. We then calculated pooled ORs and 95 % CIs. Seven studies were included in the meta-analysis. The CCND1 G allele was not associated with oral cancer in the frequency of allele comparison (G vs. A: OR = 0.882; 95 % CI = 0.684-1.137; p = 0.001 for heterogeneity). In the subgroup analysis, the CCND1 G allele was associated with a borderline significantly decreased risk of developing oral cancer in Asians in the frequency of allele comparison (G vs. A: OR = 0.800; 95 % CI = 0.636-1.006; p = 0.089 for heterogeneity), and the association between the GG genotype and oral cancer was significant in Asians with respect to both the homozygote comparison (GG vs. AA: OR = 0.644; 95 % CI = 0.491-0.843; p = 0.186 for heterogeneity) and the dominant genetic model (GG + AG vs. AA: OR = 0.713; 95 % CI = 0.584-0.870; p = 0.293 for heterogeneity). Our analysis provides evidence that genotypes for the CCND1 A870G polymorphism may be associated with an increased risk of developing oral cancer in the Asian population.

Identification of multipotent stem cells from adult dog periodontal ligament.

Periodontal diseases, which are characterized by destruction of the connective tissues responsible for restraining the teeth within the jaw, are the main cause of tooth loss. Periodontal regeneration mediated by human periodontal ligament stem cells (hPDLSCs) may offer an alternative strategy for the treatment of periodontal disease. Dogs are a widely used large-animal model for the study of periodontal-disease progression, tissue regeneration, and dental implants, but little attention has been paid to the identification of the cells involved in this species. This study aimed to characterize stem cells isolated from canine periodontal ligament (cPDLSCs). The cPDLSCs, like hPDLSCs, showed clonogenic capability and expressed the mesenchymal stem cell markers STRO-1, CD146, and CD105, but not CD34. After induction of osteogenesis, cPDLSCs showed calcium accumulation in vitro. Moreover, cPDLSCs also showed both adipogenic and chondrogenic potential. Compared with cell-free controls, more cementum/periodontal ligament-like structures were observed in CB-17/SCID mice into which cPDLSCs had been transplanted. These results suggest that cPDLSCs are clonogenic, highly proliferative, and have multidifferentiation potential, and that they could be used as a new cellular therapeutic approach to facilitate successful and more predictable regeneration of periodontal tissue using a canine model of periodontal disease.

Root resorption of primary molars without successor teeth. An experimental study in the beagle dog.

Tooth agenesis is a common craniofacial congenital malformation in humans, but little is known about the mechanisms of root resorption in this condition. The purpose of this study was to investigate the mechanisms of root resorption in primary molars without successors. An animal model without permanent tooth germs was established by surgery in beagles. The times of onset of primary molar root resorption, with and without successors, were compared. The distribution of immune cells, odontoclasts, and their activating factors were determined by histochemistry and immunohistochemistry. Root resorption of primary mandibular molars without successors began later than physiological resorption. In primary molars without permanent germs, odontoclasts and immune cells were present mainly in the apical pulp at the start of root resorption, whereas in control teeth receptor activator of nuclear factor-κB ligand (RANKL)-positive cells were found mainly in the region of the periodontal ligament. CD14(+) and CD3(+) cells were found in both the pulp and the periodontal ligament region. These results suggest that the dental pulp of primary molars, as well as immune cells, may play an important role in root resorption in primary molars without permanent tooth germs.

[The role of pulp in the root resorption of primary teeth without permanent tooth germs].

OBJECTIVE: To investigate the role of pulp in the root resorption of primary teeth without permanent tooth germs. METHODS: The animal model without permanent tooth germs was established by surgery in Beagle dog. The root resorption was observed by taking periapical radiographs periodically. The samples of mandibular bone and pulp at different resorption stages were collected. The distribution of odontoclasts and the activating factor was analyzed by histological staining and semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR). The role of pulp in the root resorption of primary teeth was tested by early pulpectomy. RESULTS: In the root resorption of primary molars without permanent teeth germs, a large number of odontoclasts were present on the pulpal surface of the root canal. Semi-quantification RT-PCR showed that the ratios of the expression of receptor activator of NF-κB ligand (RANKL) mRNA and ß-actin in the pulp of permanent teeth and primary teeth without permanent teeth germ during different periods of root resorption are 0.1314, 0.1901, 0.2111 and 0.6058 (P > 0.05). The root resorption of primary teeth without permanent teeth germs in test groups was about 5 weeks later than that of control group. CONCLUSIONS: The pulp of primary tooth played an important role in the root resorption of primary tooth without permanent tooth germ.