Effect of CD146+ SHED on bone regeneration in a mouse calvaria defect model.

OBJECTIVE: Stem cells from human exfoliated deciduous teeth (SHED) have bone regeneration ability and potential therapeutic applications. CD146, a cell adhesion protein expressed by vascular endothelial cells, is involved in osteoblastic differentiation of stem cells. The effect of CD146 on SHED-mediated bone regeneration in vivo remains unknown. We aimed to establish efficient conditions for SHED transplantation. MATERIALS AND METHODS: SHED were isolated from the pulp of an extracted deciduous tooth and cultured; CD146-positive (CD146+ ) and CD146-negative (CD146- ) populations were sorted. Heterogeneous populations of SHED and CD146+ and CD146- cells were transplanted into bone defects generated in the skulls of immunodeficient mice. Micro-computed tomography was performed immediately and 4 and 8 weeks later. Histological and immunohistochemical assessments were performed 8 weeks later. RESULTS: Bone regeneration was observed upon transplantation with CD146+ and heterogeneous populations of SHED, with significantly higher bone regeneration observed with CD146+ cells. Bone regeneration was higher in the CD146- group than in the control group, but significantly lower than that in the other transplant groups at 4 and 8 weeks. Histological and immunohistochemical assessments revealed that CD146+ cells promoted bone regeneration and angiogenesis. CONCLUSION: Transplantation of CD146+ SHED into bone defects may be useful for bone regeneration.

High-frequency near-infrared semiconductor laser irradiation suppressed experimental tooth movement-induced inflammatory pain markers in the periodontal ligament tissues of rats.

High-frequency near-infrared (NIR) semiconductor laser-irradiation has an unclear effect on nociception in the compressed lateral periodontal ligament region, a peripheral nerve region. This study aimed to investigate the effects of NIR semiconductor laser irradiation, with a power of 120 J, on inflammatory pain markers and neuropeptides induced in the compressed lateral periodontal ligament area during ETM. A NIR semiconductor laser [910 nm wavelength, 45 W maximum output power, 300 mW average output power, 30 kHz frequency, and 200 ns pulse width (Lumix 2; Fisioline, Verduno, Italy)] was used. A nickel-titanium closed coil that generated a 50-g force was applied to the maxillary left-side first molars and incisors in 7-week-old Sprague-Dawley (280-300 g) rats to induce experimental tooth movement (ETM) for 24 h. Ten rats were divided into two groups (ETM + laser, n = 5; ETM, n = 5). The right side of the ETM group (i.e., the side without induced ETM) was evaluated as the untreated group. We performed immunofluorescent histochemistry analysis to quantify the interleukin (IL)-1ß, cyclooxygenase-2 (COX2), prostaglandin E2 (PGE2), and neuropeptide [calcitonin gene-related peptide (CGRP)] expression in the compressed region of the periodontal tissue. Post-hoc Tukey-Kramer tests were used to compare the groups. Compared with the ETM group, the ETM + laser group showed significant suppression in IL-1ß (176.2 ± 12.3 vs. 310.8 ± 29.5; P < 0.01), PGE2 (104.4 ± 14.34 vs. 329.6 ± 36.52; P < 0.01), and CGRP (36.8 ± 4.88 vs. 78.0 ± 7.13; P < 0.01) expression. High-frequency NIR semiconductor laser irradiation exerts significant effects on ETM-induced inflammation. High-frequency NIR semiconductor laser irradiation can reduce periodontal inflammation during orthodontic tooth movement.

Bone Differentiation Ability of CD146-Positive Stem Cells from Human Exfoliated Deciduous Teeth.

Regenerative therapy for tissues by mesenchymal stem cell (MSCs) transplantation has received much attention. The cluster of differentiation (CD)146 marker, a surface-antigen of stem cells, is crucial for angiogenic and osseous differentiation abilities. Bone regeneration is accelerated by the transplantation of CD146-positive deciduous dental pulp-derived mesenchymal stem cells contained in stem cells from human exfoliated deciduous teeth (SHED) into a living donor. However, the role of CD146 in SHED remains unclear. This study aimed to compare the effects of CD146 on cell proliferative and substrate metabolic abilities in a population of SHED. SHED was isolated from deciduous teeth, and flow cytometry was used to analyze the expression of MSCs markers. Cell sorting was performed to recover the CD146-positive cell population (CD146+) and CD146-negative cell population (CD146-). CD146 + SHED without cell sorting and CD146-SHED were examined and compared among three groups. To investigate the effect of CD146 on cell proliferation ability, an analysis of cell proliferation ability was performed using BrdU assay and MTS assay. The bone differentiation ability was evaluated using an alkaline phosphatase (ALP) stain after inducing bone differentiation, and the quality of ALP protein expressed was examined. We also performed Alizarin red staining and evaluated the calcified deposits. The gene expression of ALP, bone morphogenetic protein-2 (BMP-2), and osteocalcin (OCN) was analyzed using a real-time polymerase chain reaction. There was no significant difference in cell proliferation among the three groups. The expression of ALP stain, Alizarin red stain, ALP, BMP-2, and OCN was the highest in the CD146+ group. CD146 + SHED had higher osteogenic differentiation potential compared with SHED and CD146-SHED. CD146 contained in SHED may be a valuable population of cells for bone regeneration therapy.

Effects of high-frequency near infrared laser irradiation on experimental tooth movement-induced pain in rats.

Discomfort and dull pain are known side effects of orthodontic treatment. Pain is expected to be reduced by near-infrared (NIR) lasers; however, the mechanism underlying effects of short-pulse NIR lasers in the oral and maxillofacial area remains unclear. This study aimed to examine the effects of high-frequency NIR diode laser irradiation on pain during experimental tooth movement (ETM) on 120 J. NIR laser with 910 nm wavelength, 45 W maximum output power, 300 mW average output power, and 200 ns pulse width (Lumix 2; (Lumix 2; Fisioline, Verduno CN, Italy) was used for the experiment. A nickel-titanium-closed coil was used to apply a 50-gf force between the maxillary left-side first molar and incisor in 7-week-old Sprague-Dawley rats (280-300 g) to induce ETM. We measured facial-grooming frequency and vacuous chewing movement (VCM) period between laser-irradiation and ETM groups. We performed immunofluorescent histochemistry analysis to quantify levels of Iba-1, astrocytes, and c-fos protein-like immunoreactivity (Fos-IR) in the trigeminal spinal nucleus caudalis (Vc). Compared with the ETM group, the laser irradiation group had significantly decreased facial-grooming frequency (P = 0.0036), VCM period (P = 0.043), Fos-IR (P = 0.0028), Iba-1 levels (P = 0.0069), and glial fibrillary acidic protein (GFAP) levels (P = 0.0071). High-frequency NIR diode laser irradiation appears to have significant analgesic effects on ETM-induced pain, which involve inhibiting neuronal activity, microglia, and astrocytes, and it inhibits c-fos, Iba-1, and GFAP expression, reducing ETM-induced pain in rats. High-frequency NIR diode laser application could be applied to reduce pain during orthodontic tooth movement.

Masticatory Function Assessment of Adult Patients With Cleft Lip and Palate After Orthodontic Treatment.

OBJECTIVE: To determine whether orthodontically treated patients with cleft lip and palate (CLP) possess a different masticatory function than those of untreated patients with normal occlusion. DESIGN: Occlusal contact area, occlusal force, as well as masseter and anterior temporal muscular activity were measured during maximum voluntary clenching (MVC) tests. Mandibular left and right lateral movements during mastication were also assessed. To further elucidate the nature of masticatory function, especially to determine the rate of abnormal jaw movement patterns, a parametric error index (EI) was set. Finally, masticatory efficiency was evaluated with a glucose sensitive measuring device. PARTICIPANTS: Fifteen patients with CLP who had previously completed the orthodontic treatments required to achieve an acceptable and more harmonious occlusion accepted to volunteer in this study along with 21 untreated patients who already possessed a normal occlusion. RESULTS: Patients with CLP showed a significantly lower occlusal force, reduced occlusal contact area, and decreased masticatory efficiency as well as significantly higher EI value when compared with controls. However, there was no significant difference when analyzing muscle activity, although masticatory efficiency was significantly different between the 2 groups. Despite this result, the scores obtained by the patients with CLP in the masticatory efficiency tests were still in the normal range. CONCLUSIONS: Orthodontic treatment for adult patients with CLP provides a satisfactory result for the patients' masticatory ability albeit significantly less ideal compared with untreated patients with normal occlusion.

Stem cell-derived conditioned media from human exfoliated deciduous teeth promote bone regeneration.

OBJECTIVES: Cleft lip and palate (CL/P) are common congenital orofacial anomalies. Autogenous iliac bone grafting closes alveolar cleft defects but requires surgical intervention. Mesenchymal stem cell culture supernatant can regenerate tissues via paracrine activity. However, little is known about the bone-regenerative effects of stem cells from human exfoliated deciduous teeth (SHED) and conditioned media (CM). Our aim was to address this. MATERIALS AND METHODS: Stem cells were isolated from primary tooth pulp and cultured. Defects were made in calvariae of immunodeficient mice and implanted with stem cell- or CM-containing atelocollagen. Regenerated bone was analysed by microcomputed tomography, haematoxylin-eosin and Masson's trichrome staining. Vascular endothelial growth factor, CD31 and CD34 expression were confirmed by immunohistochemistry, and the presence of several proteins and growth factors was verified in SHED-CM. RESULTS: Bone regeneration was enhanced in defects treated with stem cells and CM compared to that in controls 8 weeks after transplantation. Mature bone formation and angiogenesis were confirmed with CM but not with stem cells or in controls. Secretome analysis using multiple cytokine assays revealed that SHED-CM contained tissue-regenerating factors with roles in angiogenesis and osteogenesis. CONCLUSION: CM non-invasively regenerate bone and might be effective to reconstruct alveolar clefts in CL/P patients.

Examination of the effect of combined use of Er:YAG laser irradiation and mechanical force loading on bone metabolism using primary human gingival fibroblasts.

Prolonged treatment and painful tooth movement are major problems for patients undergoing orthodontic treatment. Accelerating the movement of teeth leads to shortening of the treatment period, so various studies on the movement of teeth have been conducted in the field of orthodontics. In previous studies, we performed a fiber incision-like fiberotomy using an Er:YAG laser in rats and confirmed acceleration of tooth movement. Therefore, in this study, the effect of Er:YAG laser irradiation on human gingival fibroblasts was investigated in vitro. Human gingival fibroblasts (2.0 × 105 cells) were seeded in a 6-well plate and reached 80% confluence 24 h later. A control group not undergoing any irradiation and 3 groups undergoing laser irradiation at 0.6 W, 1.0 W, and 1.2 W were investigated. Laser irradiation was performed 24 h after cell seeding. The cells were then recovered 24 h later, and the cyclooxygenase-2 (COX-2), interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), bone morphogenetic protein-2 (BMP-2), and BMP-4 genes were confirmed by PCR. In addition, a control group not undergoing any procedures, a group undergoing only Er:YAG laser irradiation, a group undergoing only centrifugal loading, and a group undergoing both Er:YAG laser irradiation and centrifugal force loading were investigated. After 24 h, cells were collected and PCR was performed. Twenty-four hours after laser irradiation, gene expressions were examined by quantitative RT-PCR, which showed that the gene expressions of COX-2, IL-1ß, TNF-α, BMP-2, and BMP-4 increased depending on the amount of irradiation energy, with the largest value at 1.2 W. Gene expressions of COX-2, IL-1ß, TNF-α, BMP-2, and BMP-4 were significantly higher in the laser with centrifugal load group than in the load group. These results suggest that genes related to bone metabolism are activated in human gingival fibroblasts when mechanical stimulation and laser irradiation are combined. This helps to elucidate the effects of Er:YAG laser irradiation during tooth movement.

Bone Regeneration in a Canine Model of Artificial Jaw Cleft Using Bone Marrow-Derived Mesenchymal Stem Cells and Carbonate Hydroxyapatite Carrier.

OBJECTIVE: Cleft lip and palate (CLP) is a common anomaly of the orofacial region. Mesenchymal stem cell (MSC) transplantation has been a focus of regenerative medicine, and its application to the repair of bone defects in patients with CLP is highly anticipated. This study investigated the potential for using MSCs to regenerate bone in a jaw cleft as well as the survival of transplanted MSCs using a canine model of CLP. DESIGN: Mesenchymal stem cells collected from the bone marrow of beagle dogs were transplanted along with carbonate hydroxyapatite into jaw clefts in beagle dogs. Mesenchymal stem cells labeled with fluorescent silica nanoparticles were also transplanted, and a histological analysis was performed 3 months later to evaluate MSC survival. RESULTS: Carbonate hydroxyapatite regeneration into bone was enhanced by cotransplantation of MSCs. The survival rate of MSCs transplanted after 3 months was 5.7%. CONCLUSIONS: Transplanted MSCs promote bone regeneration, although their survival rate is low.

Comparative characterization of stem cells from human exfoliated deciduous teeth, dental pulp, and bone marrow-derived mesenchymal stem cells.

OBJECTIVES: Mesenchymal stem cells (MSCs) are used clinically in tissue engineering and regenerative medicine. The proliferation and osteogenic differentiation potential of MSCs vary according to factors such as tissue source and cell population heterogeneity. Dental tissue has received attention as an easily accessible source of high-quality stem cells. In this study, we compared the in vitro characteristics of dental pulp stem cells from deciduous teeth (SHED), human dental pulp stem cells (hDPSCs), and human bone marrow mesenchymal stem cells (hBMSCs). MATERIALS AND METHODS: SEHD and hDPSCs were isolated from dental pulp and analyzed in comparison with human bone marrow (hBM)MSCs. Proliferative capacity of cultured cells was analyzed using a bromodeoxyuridine immunoassay and cell counting. Alkaline phosphatase (ALP) levels were monitored to assess osteogenic differentiation. Mineralization was evaluated by alizarin red staining. Levels of bone marker mRNA were examined by real-time PCR analysis. RESULTS: SHED were highly proliferative compared with hDPSCs and hBMSCs. SHED, hDPSCs, and hBMSCs exhibited dark alizarin red staining on day 21 after induction of osteogenic differentiation, and staining of hBMSCs was significantly higher than that of SHED and hDPSCs by spectrophotometry. ALP staining was stronger in hBMSCs compared with SHED and hDPSCs, and ALP activity was significantly higher in hBMSCs compared with SHED or hDPSCs. SHED showed significantly higher expression of the Runx2 and ALP genes compared with hBMSCs, based on real-time PCR analysis. In bFGF, SHED showed significantly higher expression of the basic fibroblast growth factor (bFGF) gene compared with hDPSCs and hBMSCs. CONCLUSION: SHED exhibited higher proliferative activity and levels of bFGF and BMP-2 gene expression compared with BMMSCs and DPSCs. The ease of harvesting cells and ability to avoid invasive surgical procedures suggest that SHED may be a useful cell source for application in bone regeneration treatments.

Comparison of the bone regeneration ability between stem cells from human exfoliated deciduous teeth, human dental pulp stem cells and human bone marrow mesenchymal stem cells.

Cleft lip and palate is the most common congenital anomaly in the orofacial region. Autogenous iliac bone graft, in general, has been employed for closing the bone defect at the alveolar cleft. However, such iliac bone graft provides patients with substantial surgical and psychological invasions. Consequently, development of a less invasive method has been highly anticipated. Stem cells from human exfoliated deciduous teeth (SHED) are a major candidate for playing a significant role in tissue engineering and regenerative medicine. The aim of this study was to elucidate the nature of bone regeneration by SHED as compared to that of human dental pulp stem cells (hDPSCs) and bone marrow mesenchymal stem cells (hBMSCs). The stems cells derived from pulp tissues and bone marrow were transplanted with a polylactic-coglycolic acid barrier membrane as a scaffold, for use in bone regeneration in an artificial bone defect of 4 mm in diameter in the calvaria of immunodeficient mice. Three-dimensional analysis using micro CT and histological evaluation were performed. Degree of bone regeneration with SHED relative to the bone defect was almost equivalent to that with hDPSCs and hBMSCs 12 weeks after transplantation. The ratio of new bone formation relative to the pre-created bone defect was not significantly different among groups with SHED, hDPSCs and hBMSCs. In addition, as a result of histological evaluation, SHED produced the largest osteoid and widely distributed collagen fibers compared to hDPSCs and hBMSCs groups. Thus, SHED transplantation exerted bone regeneration ability sufficient for the repair of bone defect. The present study has demonstrated that SHED is one of the best candidate as a cell source for the reconstruction of alveolar cleft due to the bone regeneration ability with less surgical invasion.

Effect of high-frequency near-infrared diode laser irradiation on periodontal tissues during experimental tooth movement in rats.

BACKGROUND AND OBJECTIVES: Tooth movement during orthodontic treatment is associated with bone neoplasticity and bone resorption on the tension and pressure sides. Previous clinical studies have suggested that low-power laser irradiation can accelerate tooth movement during orthodontic treatment, although the underlying mechanism remains unclear. In this study, we used a high-frequency near-infrared diode laser that generates less heat and examined the histologic changes in periodontal tissue during experimental tooth movement with laser irradiation. METHODS: A nickel-titanium closed coil was mounted between the maxillary left side first molar and incisor of rats to model experimental tooth movement. The laser-irradiation and the control groups were set, and the amount of movement of the first molar on 7th and 14th days after the start of pulling of the first molar tooth on the maxillary left was measured by three-dimensional analysis of µCT. After tooth movement, tissue samples from the mesial and tension sides were collected, and successive horizontal sections were prepared and examined using hematoxylin-eosin and TRAP staining and immunohistochemical staining for RANKL, OPG, ALP, and proliferating cell nuclear antigen (PCNA). Changes in tissue temperature following laser irradiation were also examined. RESULTS: Laser irradiation significantly increased tooth movement compared with non-irradiated controls. Histologic staining of the pressure-side mesial root in laser-irradiated rats revealed enhanced RANKL expression and increased numbers of TRAP-positive cells compared with controls. By contrast, on the tension side, laser irradiation led to increased expression of ALP and PCNA. These data indicate that high-frequency near-infrared diode laser irradiation on the pressure side upregulates RANKL expression and accelerates osteoclast differentiation, facilitating bone resorption, whereas bone formation is induced on the tension side. CONCLUSION: This study demonstrates that high-frequency near-infrared diode laser irradiation of periodontal tissue leads to metabolic activation, which ultimately increases the rate of tooth movement. Lasers Surg. Med. © 2018 Wiley Periodicals, Inc.

Orthodontic Treatment of a Patient With Non-Syndromic Oligodontia and a Skeletal Class â ¢ Relationship: A Case Report and Six Years' Follow-Up.

Partial edentulism, characterized by the congenital absence of six or more permanent teeth (oligodontia), excluding the third molars, manifests with variable maxillofacial skeletal morphologies and occlusions, depending on the site and number of missing teeth, complicating treatment planning for occlusion and gain of function. Herein, we describe the case of a patient with seven non-syndromic congenitally missing permanent teeth (four in the maxillary and three in the mandibular dentition, excluding the third molars), who underwent orthodontic treatment, restorative procedures, and long-term follow-up for six years. The patient was an 18-year-old man presenting with a chief complaint of congenital absence of some permanent teeth and dental malalignment on the first visit. The mandibular right central incisor, bilateral mandibular second premolars, bilateral maxillary lateral incisors, and bilateral maxillary canines were congenitally absent, while the deciduous maxillary lateral incisors, maxillary canines, and mandibular second molars were over-retained bilaterally. Since the persisting deciduous teeth were remarkably well preserved, the patient was willing to retain them as far as possible; thus, we chose orthodontic and restorative treatment to preserve the deciduous teeth. Occlusion was established after the initiation of dynamic orthodontic treatment; restorative treatment with resin-based materials was performed for the bilateral maxillary deciduous incisors, bilateral maxillary deciduous canines, and bilateral mandibular second primary molars after bracket removal, and the retention phase of orthodontic treatment was initiated. At present, six years after establishing retention, the patient exhibits a good occlusal relationship. It is difficult to achieve complete space closure using orthodontic treatment alone in cases with six or more congenitally missing permanent teeth. In addition to considerations for age, esthetic issues due to missing permanent teeth, and maxillofacial skeletal morphology, it is necessary to preserve the deciduous teeth as much as possible and ensure multidisciplinary medical cooperation, including the transition to prosthodontic treatment during long-term follow-up.

Maxillofacial Morphology as a Predictive Factor for Caries Risk in Orthodontic Patients: A Cross-Sectional Study.

This cross-sectional study aimed to explore the correlation between maxillofacial morphology and caries risk, assessed using salivary tests, in orthodontic patients. Despite enhancing the oral health-related quality of life, orthodontic treatment may adversely affect oral hygiene and increase caries risk. This study included 1071 patients all of whom underwent orthodontic examinations and salivary tests before starting orthodontic treatment at a hospital. Salivary tests were performed to assess the secretion rate, pH, buffering capacity, and counts of cariogenic bacteria. The maxillofacial morphology was evaluated using cephalometric X-rays and dental models. Statistical analyses revealed significant correlations among salivary characteristics, bacterial scores, and maxillofacial morphology. Notably, the facial angle and Y-axis values were associated with salivary secretion (p < 0.001), pH (p < 0.001), buffering capacity (p < 0.05), and cariogenic bacterial scores (p < 0.01), respectably. In conclusion, assessing the maxillofacial morphology before orthodontic treatment may aid in predicting the risk of bacterial oral diseases, offering valuable insights into personalized preventive measures. These findings underscore the potential for comprehensive evaluations to enhance caries risk assessment in orthodontic patients.

Stem cells derived from human exfoliated deciduous teeth-based media in a rat root resorption model.

OBJECTIVE: Root resorption may occur during orthodontic treatment. Herein, we investigated the effect of a culture supernatant of stem cells derived from human exfoliated deciduous teeth on root resorption. DESIGN: Twelve 8-week-old male Sprague-Dawley rats were used, and their maxillary first molars were pulled with excessive orthodontic force to induce root resorption. On days 1 and 7 after traction initiation, stem cells derived from human exfoliated deciduous teeth and alpha minimum essential medium (control group) were administered. After 14 days, the maxillary bone was evaluated for tooth movement. The expression of osteoprotegerin, receptor activator of nuclear factor κB ligand, tumor necrosis factor α, interleukin 1ß, interleukin 6, and interleukin 17 was evaluated on the compression side and tension side. RESULTS: No significant difference in tooth movement was observed between the two groups. Root resorption decreased in the group administered the culture supernatant compared with in the control. Immunohistochemical staining revealed increased osteoprotegerin expression and decreased receptor activators for nuclear factor κB ligand, tumor necrosis factor α, interleukin 1ß, interleukin 6, and interleukin 17 on the compression side and tension side. CONCLUSIONS: Administration of stem cells derived from human exfoliated deciduous teeth affected the expression of osteoprotegerin, receptor activator of nuclear factor κB ligand, tumor necrosis factor α, interleukin 1ß, interleukin 6 and interleukin 17; hence, these stem cells may inhibit root resorption by regulating their expression.

Surgical Orthodontic Treatment for Skeletal Maxillary Protrusion in Sturge-Weber Syndrome: A Case Report and Review of the Literature.

Sturge-Weber syndrome (SWS) is characterized by hemangiomas, glaucoma, and central nervous system disorders. Here, we report the case of a 15-year-old boy with SWS and upper-lip hypertrophy who underwent surgical orthodontic treatment for correction of a large overjet and deep overbite. In addition to the a large overjet and deep overbite, interdental spacing was observed in both the arches. The mandible was retrognathic and deviated to the right side. No maxillary occlusal canting or temporomandibular joint symptoms were observed. The patient was diagnosed with skeletal maxillary protrusion with spaced dentition and mandibular deviation to the right due to SWS. After presurgical orthodontic treatment using a multibracket appliance, we performed a sagittal split ramus osteotomy (SSRO) alone due to the presence of a hemangioma around the maxilla. No abnormal bleeding or cerebral hemorrhage due to increased blood pressure was observed during the SSRO. Postoperatively, the maxillary and mandibular arches were well-aligned, the deep overbite and excessive overjet improved, and bilateral angle class I molar and canine relationships were established. Furthermore, mandibular deviation improved, and the midlines of both arches approximately coincided with the facial midline. In conclusion, orthognathic surgery is feasible in patients with SWS after carefully evaluating the sites and sizes of the hemangiomas.

Inductive ability of human developing and differentiated dental mesenchyme.

The development of cell-based therapeutic strategies to bioengineer tooth tissue is a promising approach for the treatment of lost or damaged tooth tissue. The lack of a readily available cell source for human dental epithelial cells (ECs) severely constrains the progress of tooth bioengineering. Previous studies in model organisms have demonstrated that developing dental mesenchyme can instruct nondental epithelium to differentiate into enamel-forming epithelium. In this study, we characterized the ability of fetal and adult human dental mesenchyme to promote differentiation of human embryonic stem cell (hESC)-derived ECs (ES-ECs) into ameloblast-lineage cells. ES-ECs were co-cultured either with human fetal dental mesenchymal cells (FDMCs) or with adult dental mesenchymal cells (ADMCs) in either a three-dimensional culture system, or in the renal capsules of SCID mice. When co-cultured with FDMCs in vitro, ES-ECs polarized and expressed amelogenin. Tooth organ-like structures assembled with epithelium and encased mesenchyme and developing enamel-like structures could be detected in the complexes resulting from in vitro and ex vivo co-culture of ES-ECs and FDMCs. In contrast, co-cultured ES-ECs and ADMCs formed amorphous spherical structures and occasionally formed hair. Transcription factors were significantly upregulated in FDMCs compared to ADMCs including MSX1, GLI1, LHX6, LHX8,LEF1 and TBX1. In summary, FDMCs but not ADMCs had the capacity to induce differentiation of ES-ECs into ameloblast lineage cells. Further characterization of the functional differences between these two types of dental mesenchyme could enable reprogramming of ADMCs to enhance their odontogenic inductive competence.

Comparison of Orthodontic Tooth Movement of Regenerated Bone Induced by Carbonated Hydroxyapatite or Deproteinized Bovine Bone Mineral in Beagle Dogs.

Orthodontic treatments often involve tooth movement to improve dental alignment. In this study, we aimed to compare tooth movement in regenerated bone induced by two different bone fillers, carbonated hydroxyapatite (CAP) and deproteinized bovine bone mineral (DBBM). Four beagle dogs were used in this comparative study. The first, second, and fourth lower mandibular premolars (P1, P2, and P4) on both sides of the mouth were extracted, and CAP was implanted into the extraction site on the left side and DBBM into the right side. Following regenerative bone healing, orthodontic devices were attached to perform orthodontic tooth movement of the lower third mandibular premolar (P3) on both sides. X-ray examination, intraoral scan, and histological analysis were performed. The Mann-Whitney U test was used for statistical analysis, and p < 0.05 was considered significant. Bone regeneration and orthodontic tooth movement were observed in the CAP and DBBM groups. Histologically, normal periodontal tissue remodeling was observed on the compression and tension sides of CAP and DBBM. No statistical difference was observed in the number of osteoclasts around the periodontal ligament and the root resorption area. Orthodontic tooth movement of regenerated bone induced by CAP and DBBM was therefore achieved.

Effect of Er: YAG Laser Irradiation on Bone Metabolism-Related Factors Using Cultured Human Osteoblasts.

Introduction: A variety of laser treatments have been applied in numerous medical fields. In dentistry, laser treatments are used for caries, root canals, and periodontal disease, as well as surgical resection. Numerous reports have recently been published on the use of lasers for bone regeneration. If laser irradiation is found to promote the activation of bone metabolism, it might also be effective for periodontal treatment, peri-implantitis, and bone regeneration. Therefore, the present in vitro study aimed to elucidate the mechanisms underlying the effects of erbium-doped yttrium aluminum garnet (Er: YAG) laser irradiation on the bone using osteoblast-like cells. Methods: Osteoblast-like Saos 2 cells (5.0×104 cells) were seeded in 24-well plates. 24 hours after being seeded, the cells were subjected to 0.3 W, 0.6 W, and 2.0 W Er: YAG laser irradiation and then allowed to recover for 48 hours. The expression levels of bone metabolism-related factors alkaline phosphatase (ALP), bone sialoprotein (BSP), and osteoprotegerin (OPG) were then evaluated using reverse transcription-quantitative polymerase chain reaction and western blot analyses. Results: Saos 2 cells subjected to Er: YAG laser irradiation at 0.3 W, 0.6 W, and 2.0 W showed normal growth. When the Er: YAG laser irradiation and control groups were compared after 48 hours, increases were observed in ALP, BSP, and OPG gene and protein expression in the 2.0 W group. Similar results were obtained in the western blot analysis. Conclusion: These findings suggest that the Er: YAG laser irradiation of osteoblast-like cells is effective for activating bone metabolism factors.

Changes in airway patency and sleep-breathing in healthy skeletal Class II children undergoing functional activator therapy.

Purpose: Several studies agree that an abnormal maxilla-mandible relationship correlates better as an Obstructive Sleep Apnea (OSA) predictor, rather than obesity. One of the orthodontic therapies recommended for this kind of craniofacial deformity is to advance the mandible forward with an orthodontic activator, therefore, the aim of this study is to determine if healthy children that use this appliance experience a widening of the upper airway as well as an improvement in their sleep-breathing patterns. Materials and methods: 39 healthy children, 20 for activator group (10 boys and 10 girls, 4 mean age 10.9 + 0.9; BMI 16.2 + 1.4), 19 for control group (13 boys and 6 girls, mean age 5 9.8 + 1.4; BMI 17.6 + 2.1) participated in this study. They were required to submit 2 lateral cephalometric radiographs both at initial and final stages of evaluation, and finally three at- home sleep-breathing monitoring results for the activator group and one for the control group. Results: After radiographic evaluation, it was found that children in the activator group experienced an increase in all measured variables. After evaluation with the sleep monitor, an improvement of sleep-breathing was found in children from the activator group (p<0.05). Conclusion: The activator not only provides a harmonious occlusion and proper development of the mandible, but it also helps improve the quality of sleep-breathing through widening of the upper airway and reducing the number of disordered breathing events in children that undergo this therapy.

Dental and Occlusal Changes during Mandibular Advancement Device Therapy in Japanese Patients with Obstructive Sleep Apnea: Four Years Follow-Up.

Dentoskeletal changes caused by the long-term use of mandibular advancement devices (MADs) for obstructive sleep apnea (OSA) have rarely been investigated in Japan. We assessed the long-term dentofacial morphological changes in 15 Japanese patients with OSA who used two-piece MADs for an average of 4 years. Lateral cephalography analyses were performed initially and 4 years later (T1). The dental assessment included overjet, overbite, upper anterior facial height, lower anterior facial height (LAFH), total anterior facial height (TAFH), and anterior facial height ratio. Dental casts were digitized and analyzed using a 3D scanner. Changes in the apnea hypopnea index (AHI) and other sleep-assessment indices were assessed using polysomnography and out-of-center sleep testing. Radiography revealed lingual inclination of the maxillary central incisors, labial inclination of the mandibular central incisors, clockwise rotation of the mandible, and an increase in the TAFH and LAFH at T1. In the dental cast analysis, the diameter width and palatal depth tended to decrease and increase, respectively. There was a significant decrease in the AHI and other sleep assessment indices after using the MADs for approximately 4 years. However, these findings do not provide a strong basis and should be interpreted cautiously. Future studies should have a larger sample size and should further investigate the long-term occlusal and dental changes caused by the original MADs in Japanese patients with OSA.