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.

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.

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.

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.

Effects of Human Deciduous Dental Pulp-Derived Mesenchymal Stem Cell-Derived Conditioned Medium on the Metabolism of HUVECs, Osteoblasts, and BMSCs.

In this study, we assessed the effects of human deciduous dental pulp-derived mesenchymal stem cell-derived conditioned medium (SHED-CM) on the properties of various cell types. The effects of vascular endothelial growth factor (VEGF) in SHED-CM on the luminal architecture, proliferative ability, and angiogenic potential of human umbilical vein endothelial cells (HUVECs) were determined. We also investigated the effects of SHED-CM on the proliferation of human-bone-marrow mesenchymal stem cells (hBMSCs) and mouse calvarial osteoblastic cells (MC3T3-E1) as well as the expression of ALP, OCN, and RUNX2. The protein levels of ALP were examined using Western blot analysis. VEGF blockade in SHED-CM suppressed the proliferative ability and angiogenic potential of HUVECs, indicating that VEGF in SHED-CM contributes to angiogenesis. The culturing of hBMSCs and MC3T3-E1 cells with SHED-CM accelerated cell growth and enhanced mRNA expression of bone differentiation markers. The addition of SHED-CM enhanced ALP protein expression in hBMSCs and MT3T3-E1 cells compared with that of the 0% FBS group. Furthermore, SHED-CM promoted the metabolism of HUVECs, MC3T3-E1 cells, and hBMSCs. These findings indicate the potential benefits of SHED-CM in bone tissue regeneration.

Combination of Carbonate Hydroxyapatite and Stem Cells from Human Deciduous Teeth Promotes Bone Regeneration by Enhancing BMP-2, VEGF and CD31 Expression in Immunodeficient Mice.

The objective of this study was to clarify the efficiency of a combination of stem cells from human deciduous teeth and carbonate apatite in bone regeneration of calvarial defects. Immunodeficient mice (n = 5 for each group/4 groups) with artificial calvarial bone defects (5 mm in diameter) were developed, and stem cells from human deciduous teeth (SHEDs) and carbonate hydroxyapatite (CAP) granules were transplanted with an atelocollagen sponge as a scaffold. A 3D analysis using microcomputed tomography, and 12 weeks after transplantation, histological and immunohistochemical evaluations of markers of bone morphogenetic protein-2 (BMP-2), vascular endothelial growth factor (VEGF), and cluster of differentiation (CD) 31 were performed. In the 3D analysis, regenerated bone formation was observed in SHEDs and CAP, with the combination of SHEDs and CAP showing significantly greater bone regeneration than that in the other groups. Histological and immunohistochemical evaluations showed that combining SHEDs and CAP enhanced the expression of BMP-2, VEGF, and CD31, and promoted bone regeneration. This study demonstrates that the combination of SHEDs and CAP transplantation may be a promising tool for bone regeneration in alveolar defects.

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.

Impact of Maximum Tongue Pressure in Patients with Jaw Deformities Who Underwent Orthognathic Surgery.

Malocclusion and morphological abnormalities of the jawbone often affect the stomatognathic function and long-term postoperative stability in patients with jaw deformities. There are few reports on the effect of maximum tongue pressure (MTP) in these patients. We investigated the relationship between the MTP and jawbone morphology and the effect of the MTP on surgery in 42 patients with jaw deformity who underwent surgical orthodontic treatment at Hiroshima University Hospital. The MTP was measured using a tongue pressure measurement device; the average value was considered as the MTP. Based on the MTP measured before surgery, patients were classified into the high- or the low-MTP group. The clinical findings and results of the cephalometric analysis were compared. Posterior movement of the mandible in the high-MTP group was significantly lower than that in the low-MTP group. The ANB angle, overjet, and overbite in the high-MTP group were significantly smaller than those in the low-MTP group. On the other hand, there was no difference between the two groups in the measured values, indicating a labial inclination of the anterior teeth (U1 to SN, U1 to FH, IMPA, and FMIA). MTP has been suggested to affect mandibular prognathism in patients with jaw deformities.

High-frequency near-infrared diode laser irradiation suppresses IL-1ß-induced inflammatory cytokine expression and NF-κB signaling pathways in human primary chondrocytes.

Osteoarthritis (OA) and rheumatoid arthritis (RA) are common inflammation-associated cartilage degenerative diseases. Recent studies have shown that low-level diode laser treatment can reduce inflammatory cytokine expressions in cartilage. We recently reported that high-frequency low-level diode laser irradiation attenuates matrix metalloproteinases (MMPs) expression in human primary chondrocytes. However, the molecular mechanism underlying the effect of high-frequency low-level diode laser on chondrocytes remains unclear. Therefore, we aimed to elucidate the effect of high-frequency low-level diode laser irradiation on inflammatory cytokine expression in human primary chondrocytes. Normal human articular chondrocytes were treated with recombinant interleukin-1 beta (IL-1ß) for 30 min or 24 h and irradiated with a high-frequency NIR diode laser at 8 J/cm2. The expression of IL-1ß, interleukin-6, and tumor necrosis factor-alpha was assessed using western blot analysis. To evaluate the nuclear factor-kappa B (NF-κB) signaling pathway, the phosphorylation, translocation, and DNA-binding activity of NF-κB were detected using western blot analysis, immunofluorescence analysis, electrophoretic mobility shift assay, and enzyme-linked immunosorbent assay analysis. High-frequency low-level diode laser irradiation decreased inflammatory cytokine expression in IL-1ß-treated chondrocytes. Moreover, high-frequency low-level diode laser irradiation decreased the phosphorylation, nuclear translocation, and DNA-binding activity of NF-κB in the IL-1ß-treated state. However, irradiation alone did not affect NF-κB activity. Thus, high-frequency low-level diode laser irradiation at 8 J/cm2 can reduce inflammatory cytokine expressions in normal human articular chondrocytes through NF-κB regulation. These findings indicate that high-frequency low-level diode laser irradiation may reduce the expression of inflammatory cytokines in OA and RA.

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.

Baicalin inhibits root resorption during tooth movement in a rodent model.

OBJECTIVE: Baicalin mediates bone metabolism and has shown protective activity against periodontal tissue damage in a rat model of periodontitis. Therefore, we hypothesized that baicalin may inhibit the root resorption that occurs during orthodontic tooth movement and examined its effect on the histological changes in periodontal tissue that occur during tooth movement. METHODS: First molars of rats were subjected to traction using excessive orthodontic force to produce a root resorption model. Rats in the baicalin group received baicalin for 3 weeks during tooth movement, and the amount of first molar movement on day 21 after the initiation of traction was measured by three-dimensional micro-computed tomography analysis. 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 tartrate-resistant acid phosphatase (TRAP) staining and immunohistochemical staining for the receptor activator of NF-kB ligand (RANKL) and osteoprotegerin (OPG). The severity of root resorption was also determined by histological analysis. RESULTS: There was no significant intergroup difference in tooth movement during the experimental exaggerated tooth movement. In comparison with the control group, the baicalin-treated group showed increased OPG expression, suppressed RANKL expression, and significantly fewer TRAP-positive cells in the first molars. The root resorption area was significantly smaller in the baicalin group. CONCLUSIONS: Treatment with baicalin prevented root resorption without preventing tooth movement. Baicalin may be useful for the management of root resorption during orthodontic treatment.

High-Frequency Near-Infrared Diode Laser Irradiation Attenuates IL-1ß-Induced Expression of Inflammatory Cytokines and Matrix Metalloproteinases in Human Primary Chondrocytes.

High-frequency near-infrared diode laser provides a high-peak output, low-heat accumulation, and efficient biostimulation. Although these characteristics are considered suitable for osteoarthritis (OA) treatment, the effect of high-frequency near-infrared diode laser irradiation in in vitro or in vivo OA models has not yet been reported. Therefore, we aimed to assess the biological effects of high-frequency near-infrared diode laser irradiation on IL-1ß-induced chondrocyte inflammation in an in vitro OA model. Normal Human Articular Chondrocyte-Knee (NHAC-Kn) cells were stimulated with human recombinant IL-1ß and irradiated with a high-frequency near-infrared diode laser (910 nm, 4 or 8 J/cm2). The mRNA and protein expression of relevant inflammation- and cartilage destruction-related proteins was analyzed. Interleukin (IL) -1ß treatment significantly increased the mRNA levels of IL-1ß, IL-6, tumor necrosis factor (TNF) -α, matrix metalloproteinases (MMP) -1, MMP-3, and MMP-13. High-frequency near-infrared diode laser irradiation significantly reduced the IL-1ß-induced expression of IL-1ß, IL-6, TNF-α, MMP-1, and MMP-3. Similarly, high-frequency near-infrared diode laser irradiation decreased the IL-1ß-induced increase in protein expression and secreted levels of MMP-1 and MMP-3. These results highlight the therapeutic potential of high-frequency near-infrared diode laser irradiation in OA.

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.

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.

Protective effects of cilengitide on inflammation in chondrocytes under excessive mechanical stress.

Chondrocytes constantly receive external stimuli, which regulates remodeling. An optimal level of mechanical stress is essential for maintaining chondrocyte homeostasis, however, excessive mechanical stress induces inflammatory cytokines and protease, such as matrix metalloproteinases (MMPs). Therefore, excessive mechanical stress is considered to be one of the main causes to cartilage destruction leading to osteoarthritis (OA). Integrins are well-known as cell adhesion molecules and act as receptors for extracellular matrix (ECM), and are believed to control intracellular signaling pathways both physically and chemically as a mechanoreceptor. However, few studies have focused on the roles and functions of integrins in inflammation caused by excessive mechanical stress. In this study, we examined the relationship between integrins (αVß3 and αVß5) and the expression of inflammatory factors under mechanical loading in chondrocytes by using an integrin receptor antagonist (cilengitide). Cilengitide suppressed the gene expression of interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), matrix metalloproteinase-3 (MMP-3), and MMP-13 induced by excessive mechanical stress. In addition, the protein expression of IL1-ß and MMP-13 was also inhibited by the addition of cilengitide. Next, we investigated the involvement of intracellular signaling pathways in stress-induced integrin signaling in chondrocytes by using western blotting. The levels of p-FAK, p-ERK, p-JNK, and p-p38 were enhanced by excessive mechanical stress and the enhancement was suppressed by treatment with cilengitide. In conclusion, this study revealed that excessive mechanical stress may activate integrins αVß3 and αVß5 on the surface of chondrocytes and thereby induce an inflammatory reaction by upregulating the expression of IL-1ß, TNF-α, MMP-3, and MMP-13 through phosphorylation of FAK and MAPKs.

Success rates in isolating mesenchymal stem cells from permanent and deciduous teeth.

Stem cells from human exfoliated deciduous teeth (SHED) and human dental pulp stem cells (hDPSCs) have emerged as attractive cell sources for bone regeneration. However, the specific teeth and the conditions most suitable for stem cell isolation remain unclear. Therefore, the success rate of SHED and hDPSCs isolation, the patient age and remaining root length in deciduous teeth were evaluated. Successful isolation was defined as when the cell culture was maintained up to the third passage without any contamination or other issues. Remaining tooth length was calculated using the root-to-crown ratio from patient X-rays and compared to the norm value from the literature. The overall successful isolation rate of SHED and hDPSCs was 82% and 70%. The average patient ages at extraction of the deciduous teeth and permanent teeth were 11 years and 9 months, and 22 years and 10 months respectively. In the successful SHED group, the average remaining root length of the anterior deciduous teeth was 71.4%, and that of the deciduous molars was 61.4%. Successful isolation appears to be associated with patient age, length of the remaining root, and also mechanical stress and other factors. Tooth selection criteria need to be identified to improve the success rate.

Molecular biological and histological effects of Er:YAG laser irradiation on tooth movement.

The aim of this study was to evaluate the effects of a fiberotomy-like procedure using Er:YAG laser irradiation on the velocity of orthodontic tooth movement. To produce experimental tooth movement in rats, orthodontic force was applied to the upper first molars with a nickel-titanium closed coil. The right molars were irradiated with an Er:YAG laser while the non-irradiated left molars were used as controls. The rats were sacrificed at 4 weeks after the start of tooth movement and the distance between the mesial side of the second molar and the distal side of the upper first molar was measured on CT images. The amount of tooth movement was significantly greater in the irradiation group than in the control group. The TRAP-positive nuclei count at the pressure site was higher in the laser-irradiation group than in the control group. Expression of RANKL and ALP was higher at the mesial-coronal pressure site in the laser-irradiation group than in the control group. In addition, expression of OPG was higher at the pressure site in the control group than in the laser-irradiation group. These results suggest that a fiberotomy-like procedure using an Er:YAG laser stimulates osteoclasts and osteoblasts and may promote bone metabolism in the context of experimental tooth movement.

Effects of Nd:YAG low-level laser irradiation on cultured human osteoblasts migration and ATP production: in vitro study.

Low-level laser therapy has become one of the fastest growing fields of medicine in recent years. Many in vivo and in vitro studies have shown that laser irradiation activates a range of cellular processes in a variety of cell types and can promote tissue repair. However, few in vitro experiments have evaluated the effects of laser irradiation on cells in real time. The purpose of this study was to examine the effects of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser irradiation on the migration of cultured human osteoblasts. A dedicated 96-well plate was used, and confluent cultures of the human osteoblast-like cell line, Saos-2, were injured with a wound maker. The wounded cells were then exposed to the Nd:YAG laser (wavelength of 1064 nm) for 60 s at 0.3 W (10 pps, 30 mJ). The total energy density was about 10.34 J/cm2. Images of the wounds were automatically acquired inside the CO2 incubator by the IncuCyte ZOOM™ software. In addition, after laser irradiation, the production of adenosine triphosphate (ATP) was measured using the CellTiter-Glo™ Luminescent Cell Viability Assay. Migration of cells from the border of the original scratch zone was accelerated by laser irradiation. In addition, compared with the control group, significant enhancement of ATP production was observed in the irradiated group. The present study showed that Nd:YAG laser irradiation (wavelength of 1064 nm, 0.3 W, 10 pps, 30 mJ, 10.34 J/cm2, irradiation time 60 s) may contribute to the regeneration of bone tissues owing to enhanced osteoblast cell migration.

The effect of mesenchymal stem cells on osteoclast precursor cell differentiation.

Transplantation of mesenchymal stem cells (MSCs) has been extensively studied in the field of regenerative medicine. Bone regeneration is achieved via the interaction of osteoblasts and osteoclasts. However, the influence of MSCs on osteoclasts is unknown. The purpose of this study was to investigate the effect of MSCs on the expression of genes for osteoclast differentiation factors using qPCR after indirect co-culture of MSCs and RAW264 cells. The numbers of osteoclasts after addition of soluble receptor activator of nuclear factor kappa B (NF-κB) ligand (sRANKL) were also compared. Expression of osteoprotegerin (OPG) by MSCs was significantly elevated in co-culture over time. The differentiation of RAW264 cells into mature osteoclasts following addition of sRANKL was significantly inhibited by co-culture with MSCs. Expression of RANK, colony stimulating factor 1 receptor, NF-κB, and nuclear factor of activated T-cell cytoplasmic 1 in RAW264 cells was significantly inhibited by co-culture with MSCs. Expression of OPG protein was higher in co-culture with RAW264 cells than in MSCs alone, and the expression level was clearly higher than that of RANKL. MSCs appeared to inhibit osteoclast differentiation via expression of OPG.