Genetic Comparison of Stemness of Human Umbilical Cord and Dental Pulp.

This study focuses on gene expression patterns and functions in human umbilical cord (UC) and dental pulp (DP) containing mesenchymal stem cells (MSCs). DP tissues were collected from 25 permanent premolars. UC tissue samples were obtained from three newborns.

Multiple teeth fractures in dentinogenesis imperfecta: a case report.

Dentinogenesis imperfecta (DGI) is a hereditary defect consisting of opalescent teeth composed of irregularly formed and hypomineralized dentin. This paper presents the multiple fractures of DGI-affected teeth and suggests the reason of low fracture resistance by observing the dentin microstructures directly using scanning electron microscope (SEM) and by measuring its surface hardness using the Vickers hardness test. SEM revealed that while the enamel microstructure was similar in the DGI-affected and normal teeth, the microstructure of the DGI-affected dentin was poorly woven and more loosely packed than that of the normal dentin.

Microscopic analysis of molar--incisor malformation.

Objective: Molar-incisor malformation (MIM) is a newly discovered type of dental anomaly that involves a characteristic root malformation of the permanent first molars. The aim of this study was to reveal the microstructure of MIM teeth in order to determine their origin.

Study Design: Four MIM teeth were extracted from a 9-year-old girl due to severe mobility.

The Rect-spring: a new device for treating ectopically erupting permanent molars.

The Rect-spring, a new device that simply and effectively resolves ectopically erupting molars, may be applied in cases where the ectopically erupted molar is entrapped by more than two mm. Its design, scientifically logical for changing the direction of force, delivers a continuous distalizing and uprighting force. The Rect-spring can be easily manufactured at chairside and delivered on the same day without the need to take impressions or perform laboratory procedures.

Distinctive genetic activity pattern of the human dental pulp between deciduous and permanent teeth.

Human deciduous and permanent teeth exhibit different developmental processes, morphologies, histological characteristics and life cycles. In addition, their pulp tissues react differently to external stimuli, such as the pulp sensitivity test, dental trauma and pulp therapy materials. These suggest differences in gene expression and regulation, and in this study we compared gene-expression profiles of the human dental pulp from deciduous and permanent teeth.

In vitro and in vivo characteristics of stem cells from human exfoliated deciduous teeth obtained by enzymatic disaggregation and outgrowth.

Objective: Stem cells from human exfoliated deciduous teeth (SHED) are a good source of dental tissue for regeneration therapy, and can be obtained using different primary culture methods. The aim of this study was to determine the differences in the in vitro and in vivo characteristics between SHED isolated via enzymatic disaggregation (e-SHED) and outgrowth (o-SHED) primary culture methods.

Design: Dental pulp stem cells were isolated from 14 exfoliated deciduous teeth by enzymatic disaggregation (n=7) and outgrowth (n=7).

Comparative gene-expression analysis of the dental follicle and periodontal ligament in humans.

The human dental follicle partially differentiates into the periodontal ligament (PDL), but their biological functions are different. The gene-expression profiles of the dental follicle and PDL were compared using the cDNA microarray technique. Microarray analysis identified 490 genes with a twofold or greater difference in expression, 365 and 125 of which were more abundant in the dental follicle and PDL, respectively.

Activation of G Proteins by Aluminum Fluoride Enhances RANKL-Mediated Osteoclastogenesis.

Receptor activator of NF-κB ligand (RANKL)-induced osteoclastogenesis is accompanied by intracellular Ca(2+) mobilization in a form of oscillations, which plays essential roles by activating sequentially Ca(2+)/calmodulin-dependent protein kinase, calcineurin and NFATc1, necessary in the osteoclast differentiation. However, it is not known whether Ca(2+) mobilization which is evoked in RANKL-independent way induces to differentiate into osteoclasts. In present study, we investigated Ca(2+) mobilization induced by aluminum fluoride (AlF4 (-)), a G-protein activator, with or without RANKL and the effects of AlF4 (-) on the osteoclastogenesis in primary cultured mouse bone marrow-derived macrophages (BMMs).

Viability of pulp stromal cells in cryopreserved deciduous teeth.

The cryopreservation of exfoliated deciduous teeth and harvesting of stem cells from them as required would reduce the costs and efforts associated with banking stem cells from primary teeth. The aim of this study was determine whether the viability of pulp stromal cells from deciduous teeth was influenced by the cryopreservation process itself or the period of cryopreservation. In total, 126 deciduous teeth were divided into three groups: (1) fresh, (2) cryopreserved for <3 months (cryo<3), and (3) cryopreserved for 3-9 months (cryo3-9).

Comparative gene expression analysis of the human periodontal ligament in deciduous and permanent teeth.

There are histological and functional differences between human deciduous and permanent periodontal ligament (PDL) tissues. The aim of this study was to determine the differences between these two types of tissue at the molecular level by comparing their gene expression patterns. PDL samples were obtained from permanent premolars (n = 38) and anterior deciduous teeth (n = 31) extracted from 40 healthy persons.

Continued root development of a surgically repositioned human incisor tooth germ.

Conventional orthodontic traction may not be the treatment of choice in cases of inverted impaction of a maxillary incisor, especially when located near the alveolar crest. Poor prognosis is associated with the limited space for proper root development, resulting in a root too short for normal function and/or a severely dilacerated root interrupting the force-induced positioning. The surgical repositioning of ectopic impacted toothgerm before the development of root could be a valuable alternative choice of treatment before the decision of extraction.

Shh signaling is essential for rugae morphogenesis in mice.

Palatal ridges, or rugae palatinae, are corrugated structures observed in the hard palate region. They are found in most mammalian species, but their number and arrangement are species-specific. Nine palatal rugae are found in the mouse secondary palate.

Physical properties of resin-reinforced glass ionomer cement modified with micro and nano-hydroxyapatite.

Hydroxyapatite is a biologically compatible material and a major component of dental enamel and bone tissue. Because of its biocompatibility and structural similarity to human teeth and the skeletal system, a number of dental studies have evaluated its application as a bone substitute or dental restorative material. This study was to evaluate the differences in bonding strength and resistance to demineralization between micro-hydroxyapatite and nano-hydroxyapatite added to self-cured resin-reinforced/modified glass ionomer cement.

Incidence and relationship of an additional root in the mandibular first permanent molar and primary molars.

Objectives: The mandibular first permanent and primary molars occasionally have an additional root located distolingually. This study aimed to determine the incidences of an additional root in these molars and their relationship.

Study Design: This study involved 4050 children for whom periapical radiographs of the mandibular molar area were available.

Oral manifestations of a child with chronic vomiting.

Perimolysis is a type of intrinsic erosion--an irreversible dental demineralization linked to chronic regurgitation--which causes teeth to be more susceptible to dental caries. The purpose of this case report was to study a 35-month-old chronic vomiting child who visited the Department of Pediatric Dentistry in Yonsei Dental Hospital, Seoul, South Korea, for an evaluation of and treatment for the loss of tooth structure of his primary teeth. To prevent further destruction of the teeth and maintain occlusal height, all the posterior teeth were restored with stainless steel crowns and all the anterior teeth were restored with resin veneer crowns after pulpal treatment under general anesthesia.

Oral self-mutilation in the Lesch-Nyhan syndrome.

Lesch-Nyhan Syndrome is a disorder caused by congenital absence of a purine metabolic enzyme, hypoxanthine-guanine phosphoribosyl transferase (HPRT). This syndrome is characterized clinically by mental retardation, chorea, athetosis, hyperuricemia, uricosuria and self-mutilation. This report is of two children, who are cousins, both of whom have Lesch-Nyhan syndrome and presented with severe self-mutilation wounds on their lip(s).