Seunghye Kim

Characteristics of stem cells from human exfoliated deciduous teeth (SHED) from intact cryopreserved deciduous teeth

The aim of this study is to compare the characteristics of stem cells derived from human exfoliated deciduous teeth (SHED) from cryopreserved intact deciduous teeth with those of fresh SHED. In total, 20 exfoliated deciduous teeth were randomly divided into a fresh group (f-SHED; n = 11) and cryopreserved group (c-SHED; n = 9; stored for 1-8 months). Following thawing and separation of the pulp, the SHED cells were cultured, and the characteristics as mesenchymal stem cells were investigated using proliferation assays, cell-cycle analysis, colony-forming unit-fibroblast (CFU-F) assays, and flow cytometry analyses. Furthermore, differentiation into adipogenic and osteogenic lineages was investigated in vitro as well as in vivo via transplantation in mice. We found no significant differences between the two groups in the proliferation analyses, in the expression of mesenchymal stem cell markers, or in the adipogenic and osteogenic differentiation in vitro (p < 0.05). Furthermore, the in vivo transplantation results showed no significant differences in the quantity of bone tissue that formed or in histochemistry performance (p < 0.05). In conclusion, cryopreservation of intact exfoliated deciduous teeth appears to be a useful method for preserving SHED.

Comparative Gene Expression Analysis of the Coronal Pulp and Apical Pulp Complex in Human Immature Teeth

INTRODUCTION This study determined the gene expression profiles of the human coronal pulp (CP) and apical pulp complex (APC) with the aim of explaining differences in their functions. METHODS Total RNA was isolated from the CP and APC, and gene expression was analyzed using complementary DNA microarray technology. Gene ontology analysis was used to classify the biological function. Quantitative reverse-transcription polymerase chain reaction and immunohistochemical staining were performed to verify microarray data. RESULTS In the microarray analyses, expression increases of at least 2-fold were present in 125 genes in the APC and 139 genes in the CP out of a total of 33,297 genes. Gene ontology class processes found more genes related to immune responses, cell growth and maintenance, and cell adhesion in the APC, whereas transport and neurogenesis genes predominated in the CP. Quantitative reverse-transcription polymerase chain reaction and immunohistochemical staining confirmed the microarray results, with DMP1, CALB1, and GABRB1 strongly expressed in the CP, whereas SMOC2, SHH, BARX1, CX3CR1, SPP1, COL XII, and LAMC2 were strongly expressed in the APC. CONCLUSIONS The expression levels of genes related to dentin mineralization, neurogenesis, and neurotransmission are higher in the CP in human immature teeth, whereas those of immune-related and tooth development-related genes are higher in the APC.

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. In this case report, an impacted immature incisor toothgerm in complete inversion was surgically repositioned using a closed-flap technique in a boy who was 6 years 8 months old. Continued root formation and spontaneous eruption were observed after surgery over the 51-month follow-up period, without pulpal or periodontal complications.

A CASE OF DELAYED ERUPTION IN A CHILD WITH MONOSTOTIC FIBROUS DYSPLASIA

Fibrous dysplasia is a developmental tumor-like condition that is characterized by replacement of normal bone by an excessive proliferation of cellular fibrous connective tissue intermixed with irregular bony trabeculae. Craniofacial lesions may cause facial pain, headache, cranial asymmetry, facial deformity, tooth displacement and visual or auditory impairment. In this case, a 2-year-9-month old boy who was diagnosed as the fibrous dysplasia showed delayed eruption on affected area. Teeth of left lateral dentition group have erupted completely but teeth of right lateral dentition group are erupting slowly. Eruption and maturation of affected teeth are in progress, so continuous observation is required presently. If the eruption state stops, surgical opening or forced eruption of the impacted teeth will be considered.

Cytokine Expression of Stem Cells Originating from the Apical Complex and Coronal Pulp of Immature Teeth

Introduction: The aim of this study was to measure and compare the expression levels of cytokines from developing apical complex cells (DACCs) and dental pulp stem cells (DPSCs) of the immature tooth. Methods: DPSC‐conditioned medium (CM) and DACCs‐CM were obtained from human young teeth, and 174 cytokines secreted from each CM were identified and compared. A cytokine membrane array and enzyme‐linked immunosorbent assay were used to measure and compare the expression levels of the cytokines. Immunocytochemistry targeting insulin‐like growth factor‐1 and neurotrophin‐3 was additionally performed. Results: There were statistically significant differences in the expression levels of 25 cytokines: 22 and 3 were expressed more strongly in DPSCs‐CM and DACCs‐CM, respectively. Odontoblast differentiation‐related cytokines were more strongly expressed in DPSCs‐CM, while cell‐proliferation–related cytokines were more strongly expressed in DACCs‐CM. Proinflammatory and anti‐inflammatory cytokines were predominantly expressed in DPSCs‐CM and DACCs‐CM, respectively. Conclusions: DPSCs may exert a stronger paracrine effect than DACCs on regeneration of the dentin–pulp complex, in terms of odontoblast differentiation. HighlightsThis study compared the expression levels of different cytokines using a cytokine membrane array, with additional enzyme‐linked immunosorbent assay and immunocytochemistry (ICC) tests performed to elucidate the paracrine effects of DPSCs and DACCs.Cytokines associated with odontoblast differentiation (NT‐3, BMP‐4, TGF‐&bgr;1, and TGF‐&bgr;3) were expressed more strongly in DPSCs than in DACCs. It could be suggested that cytokines expressed in DPSCs provide a more suitable environment for odontoblast differentiation for the same epigenetic signals.The secretion level of cell‐proliferation–related cytokines was higher for DACCs than for DPSCs. The stronger expression of proliferation cytokines observed in this study corroborates the high proliferation activity of the DACCs found in previous in vitro studies. Thus, the developing apical complex of the young tooth acts as a growth center via the proliferation ability of cytokines expressed in the periphery.This study is the first to attempt to measure and compare the expression levels of cytokines from DACCs and DPSCs of immature teeth. The findings have demonstrated that DPSCs may exert a stronger paracrine effect than DACCs on regeneration of the dentin–pulp complex, in terms of odontoblast differentiation.

Relief of Upper Airway Obstruction Using a Cervical Splint for Young Patients with Cerebral Palsy

13-year old boy with spastic quadriplegia cerebral palsy visited dental clinic with chief complaints of mouth breathing and malocclusion. His mouth was constantly open at the resting position, with his mandible and tongue displaced downward. He breathed through his mouth, making a constant gurgling sound, a sign of upper airway obstruction. To enhance his mandible position, vertical chin cap was first considered, but it was not sufficient to reduce the gurgling sound or ease breathing. Then, cervical splint was considered, which effectively decreased the gurgling sound by repositioning his mandible to the anterior-superior position. Oxygen saturation was increased when the cervical splint was used. Cervical splint can effectively assist breathing in patients with cerebral palsy, but it should be carefully applied as long-term use can result in unexpected complications. Under instruction by a physician regarding proper usage, a cervical splint can be applied to assist breathing in patients with cerebral palsy.

Irritation Fibroma Associated with Ectopic Eruption of the Maxillary Incisor

Irritation fibroma is a common hyperplastic lesion of the oral mucosa that can occur in response to chronic irritation or trauma. This report presents an unusual case of irritation fibroma associated with ectopic eruption of the maxillary left central incisor in a patient with Angelman syndrome. Considering the patient`s medical history and cooperative ability, excisional biopsy under intramuscular sedation using midazolam was performed. The patient exhibited successful healing without lesion recurrence. It is important to perform histopathological examination followed by excisional biopsy, because other benign or malignant tumors may mimic the clinical appearance of an irritation fibroma.

SPONTANEOUS ERUPTION OF ECTOPIC IMPACTED TOOTH BY INTENTIONAL EXTRACTION OF DECIDUOUS TOOTH

When many factors involved in the eruption of the teeth act as negative effects, they can cause eruption disturbance. Periodic observation, space acquirement, surgical exposure, orthodontic traction, orthodontic traction accompanied with surgical exposure, and surgical repositioning are considered as the treatment options of an impacted tooth, which is a form of eruption disturbance. In the first case, a male patient, age 9, visited Yonsei University Dental Hospital (YUDH) with a chief complaint of ectopic impaction of the upper left lateral incisor. We extracted the upper left primary lateral incisor and primary canine, and 5 months later, a window opening procedure was executed. Eight months later, the upper left lateral incisor partially erupted, and 18 months after the extraction, the axis of the tooth improved and the tooth erupted spontaneously. In the second case, a male patient, age 10, visited YUDH with a chief complaint of ectopic impaction of the upper right first premolar. We extracted the upper right first primary molar. Ten months later, the upper right first premolar erupted partially, and 19 months after the extraction, the upper right first premolar erupted spontaneously. We reported two cases in which improvement of eruption path and spontaneous eruption of an ectopic impacted tooth was achieved by extracting the deciduous tooth which interfered with the proper eruption of it.

MARSUPIALIZATION OF RANULA

Ranula is a mucosal cyst that occurs in the mouth floor. This is a pseudo cyst caused by mucous retention within the tissue due to the rupture of catheter in the salivary gland. Ranula occurs mainly in a unilateral form and is characterized by painless bluish transparent swelling, with a increasing mass size. If the size is large, it can cause discomfort during swallowing, pronounciation, and mastication, but external swelling and infection is rare. Treatments include observation for spontaneous resolution, simple incision and drainage, marsupialization and excision. Marsupialization done by removing parts of the cyst wall and connecting it to the oral mucosa. It is a conservative procedure and recommended for children. It has advantages such as maintaining outline of oral tissue and less risk of damaging anatomic structure. Recurrence is common, mostly occurring within 4 months after surgery. This case is about a eight-year-old girl with ranula on the right mouth floor. This patient was treated with marsupialization that is one of treatment for ranula, and recurrence was not observed.

ROOT MALFORMATION OF PERMANENT INCISORS BY ALVEOLAR BONE FRACTURE

During tooth formation, tooth development can be affected by physical action or metabolic changes around dental follicle. Especially trauma to primary dentition is the most representative physical factor that can cause development disorders of succedaneous tooth. Enamel hypoplasia and crown discoloration of succedaneous tooth are common complications of trauma. And impaction, ectopic eruption, arrest of root formation and root dilaceration of succedaneous tooth are rare. In this case, a 6-year and 5-month-old female patient visited for dental evaluation after trauma. She was diagnosed with alveolar bone fracture near upper front teeth, extrusion of the upper right and left primary central incisors, intrusion of the upper right primary lateral incisor, and palatal luxation of the upper left primary lateral incisor. Upper right and left primary central incisors with severe mobility were extracted, with gingival suture on the day of the visit. During 24 months check up, root dilacerations were found near the cemento enamel junction in the upper lateral incisors and arrests of root formation were found on the coronal 1/3 of the root in the upper central incisors. Although alveolar bone fracture is rare type of trauma in children, a thorough examination of alveolar bone is essential for prognosis and following treatment in patients with trauma.