Functional modulation of lysophosphatidic acid type 2 G-protein coupled receptor facilitates alveolar bone formation.

Lipid biosynthesis is recently studied its functions in a range of cellular physiology including differentiation and regeneration. However, it still remains to be elucidated in its precise function. To reveal this, we evaluated the roles of lysophosphatidic acid (LPA) signaling in alveolar bone formation using the LPA type 2 receptor (LPAR2) antagonist AMG-35 (Amgen Compound 35) using tooth loss without periodontal disease model which would be caused by trauma and usually requires a dental implant to restore masticatory function. In this study, in vitro cell culture experiments in osteoblasts and periodontal ligament fibroblasts revealed cell type-specific responses, with AMG-35 modulating osteogenic differentiation in osteoblasts in vitro. To confirm the in vivo results, we employed a mouse model of tooth loss without periodontal disease. Five to 10 days after tooth extraction, AMG-35 facilitated bone formation in the tooth root socket as measured by immunohistochemistry for differentiation markers KI67, Osteocalcin, Periostin, RUNX2, transforming growth factor beta 1 (TGF-ß1) and SMAD2/3. The increased expression and the localization of these proteins suggest that AMG-35 elicits osteoblast differentiation through TGF-ß1 and SMAD2/3 signaling. These results indicate that LPAR2/TGF-ß1/SMAD2/3 represents a new signaling pathway in alveolar bone formation and that local application of AMG-35 in traumatic tooth loss can be used to facilitate bone regeneration and healing for further clinical treatment.

Developmental roles of glomerular epithelial protein-1 in mice molar morphogenesis.

Glomerular epithelial protein-1 (Glepp1), a R3 subtype family of receptor-type protein tyrosine phosphatases, plays important role in the activation of Src family kinases and regulates cellular processes such as cell proliferation, differentiation, and apoptosis. In this study, we firstly examined the functional evaluation of Glepp1 in tooth development and morphogenesis. The precise expression level and developmental function of Glepp1 were examined by RT-qPCR, in situ hybridization, and loss and gain of functional study using a range of in vitro organ cultivation methods. Expression of Glepp1 was detected in the developing tooth germs in cap and bell stage of tooth development. Knocking down Glepp1 at E13 for 2 days showed the altered expression levels of tooth development-related signaling molecules, including Bmps, Dspp, Fgf4, Lef1, and Shh. Moreover, transient knock down of Glepp1 revealed alterations in cellular physiology, examined by the localization patterns of Ki67 and E-cadherin. Similarly, knocking down of Glepp1 showed disrupted enamel rod and interrod formation in 3-week renal transplanted teeth. In addition, due to attrition of odontoblastic layers, the expression signals of Dspp and the localization of NESTIN were almost not detected after knock down of Glepp1; however, their expressions were increased after Glepp1 overexpression. Thus, our results suggested that Glepp1 plays modulating roles during odontogenesis by regulating the expression levels of signaling molecules and cellular events to achieve the proper structural formation of hard tissue matrices in mice molar development.

The role of O-GlcNAcylation mediated by OGT during tooth development.

To understand the mechanisms underlying tooth morphogenesis, we examined the developmental roles of important posttranslational modification, O-GlcNAcylation, which regulates protein stability and activity by the addition and removal of a single sugar (O-GlcNAc) to the serine or threonine residue of the intracellular proteins. Tissue and developmental stage-specific immunostaining results against O-GlcNAc and O-GlcNAc transferase (OGT) in developing tooth germs would suggest that O-GlcNAcylation is involved in tooth morphogenesis, particularly in the cap and secretory stage. To evaluate the developmental function of OGT-mediated O-GlcNAcylation, we employed an in vitro tooth germ culture method at E14.5, cap stage before secretory stage, for 1 and 2 days, with or without OSMI-1, a small molecule OGT inhibitor. To examine the mineralization levels and morphological changes, we performed renal capsule transplantation for one and three weeks after 2 days of in vitro culture at E14.5 with OSMI-1 treatment. After OGT inhibition, morphological and molecular alterations were examined using histology, immunohistochemistry, real-time quantitative polymerase chain reaction, in situ hybridization, scanning electron microscopy, and ground sectioning. Overall, inhibition of OGT resulted in altered cellular physiology, including proliferation, apoptosis, and epithelial rearrangements, with significant changes in the expression patterns of ß-catenin, fibroblast growth factor 4 (fgf4), and sonic hedgehog (Shh). Moreover, renal capsule transplantation and immunolocalizations of Amelogenin and Nestin results revealed that OGT-inhibited tooth germs at cap stage exhibited with structural changes in cuspal morphogenesis, amelogenesis, and dentinogenesis of the mineralized tooth. Overall, we suggest that OGT-mediated O-GlcNAcylation regulates cell signaling and physiology in primary enamel knot during tooth development, thus playing an important role in mouse molar morphogenesis.

Resveratrol enhances bone formation by modulating inflammation in the mouse periodontitis model.

OBJECTIVE: To evaluate the effect of resveratrol on periodontal bone regeneration after local delivery and to determine its effect on inflammatory mediators. BACKGROUND: Resveratrol is considered an anti-inflammatory polyphenolic stilbene involved in the modulation of inflammation. MATERIALS AND METHODS: Periodontitis was induced in mouse molars using a 5-day ligature model followed by the left second molar extraction and 50 µM resveratrol treatment for 1 and 2 weeks. We then examined specimens treated for 1 week histologically and with immunostaining. Microfocus-computed tomography (micro-CT) was used to examine the bone volume formation. RESULTS: After 1 week of treatment, proinflammatory cytokine levels (TNF-alpha and IL6), cells exhibiting neutrophil and macrophage marker (MPO), cell proliferation marker (Ki67), and preosteoblastic marker (RUNX2) reactivity decreased in the resveratrol-treated specimens compared to the control group. In contrast, we observed a higher number of CD31-, F4/80-, and osteocalcin- (OCN-) positive cells in the resveratrol-treated specimens. After 2 weeks, micro-CT confirmed an increased bone mass in the region of the extraction socket in the resveratrol-treated group. CONCLUSION: After 1 week, the resveratrol-treated specimens revealed evidence of inflammation modulation compared to the control group. These data suggest that resveratrol not only affects inflammation control but also is useful for treating periodontitis-related tissue defects and bone regeneration.

Effects of resveratrol on bone-healing capacity in the mouse tooth extraction socket.

BACKGROUND AND OBJECTIVE: After tooth extraction, the extraction socket undergoes several steps of soft and hard tissue healing. The healing process of the extraction socket is modulated by a range of signaling factors and biochemical agents. It has been reported that resveratrol, a polyphenolic compound, exhibits various biological effects, including anti-inflammatory, anti-carcinogenic, antioxidant, and anti-aging effects, and protects cardiovascular and bone tissues. In this study, we examined the cellular effects of resveratrol on human periodontal ligament (hPDL) cells and osteoblast-like (MC3T3-E1) cells and evaluated the bone-healing capacity of tooth extraction sockets in mice. MATERIAL AND METHODS: Resveratrol was applied to hPDL and MC3T3-E1 cells to detect cell proliferation and alkaline phosphatase (ALP) activity, and qPCR was employed to understand the gene expression level in vitro. For in vivo experiment, six-week-old C57BL/6 male mice were randomly divided into control (n = 15) and experimental (n = 15) groups and maxillary first molars were extracted by surgery. Experimental groups received 50-µM resveratrol on extraction sockets and analyzed the degree of new bone formation. RESULTS: Treatment of hPDL and MC3T3-E1 cells with resveratrol increased the cell proliferation and ALP activity and enhanced the expression of ALP, BMP-2, BMP-4, and OC genes. Resveratrol enhanced new bone formation in the lingual extraction socket in mice. CONCLUSION: These results suggest that resveratrol increases the cellular physiology of PDL and osteoblast including their proliferation and differentiation and may play an important role in bone-healing capacity after tooth extraction.

Facilitation of Bone Healing Processes Based on the Developmental Function of Meox2 in Tooth Loss Lesion.

In the present study, we examined the bone healing capacity of Meox2, a homeobox gene that plays essential roles in the differentiation of a range of developing tissues, and identified its putative function in palatogenesis. We applied the knocking down of Meox2 in human periodontal ligament fibroblasts to examine the osteogenic potential of Meox2. Additionally, we applied in vivo periodontitis induced experiment to reveal the possible application of Meox2 knockdown for 1 and 2 weeks in bone healing processes. We examined the detailed histomorphological changes using Masson's trichrome staining and micro-computed tomography evaluation. Moreover, we observed the localization patterns of various signaling molecules, including α-SMA, CK14, IL-1ß, and MPO to examine the altered bone healing processes. Furthermore, we investigated the process of bone formation using immunohistochemistry of Osteocalcin and Runx2. On the basis of the results, we suggest that the knocking down of Meox2 via the activation of osteoblast and modulation of inflammation would be a plausible answer for bone regeneration as a gene therapy. Additionally, we propose that the purpose-dependent selection and application of developmental regulation genes are important for the functional regeneration of specific tissues and organs, where the pathological condition of tooth loss lesion would be.

Developmental Roles of FUSE Binding Protein 1 (Fubp1) in Tooth Morphogenesis.

FUSE binding protein 1 (Fubp1), a regulator of the c-Myc transcription factor and a DNA/RNA-binding protein, plays important roles in the regulation of gene transcription and cellular physiology. In this study, to reveal the precise developmental function of Fubp1, we examined the detailed expression pattern and developmental function of Fubp1 during tooth morphogenesis by RT-qPCR, in situ hybridization, and knock-down study using in vitro organ cultivation methods. In embryogenesis, Fubp1 is obviously expressed in the enamel organ and condensed mesenchyme, known to be important for proper tooth formation. Knocking down Fubp1 at E14 for two days, showed the altered expression patterns of tooth development related signalling molecules, including Bmps and Fgf4. In addition, transient knock-down of Fubp1 at E14 revealed changes in the localization patterns of c-Myc and cell proliferation in epithelium and mesenchyme, related with altered tooth morphogenesis. These results also showed the decreased amelogenin and dentin sialophosphoprotein expressions and disrupted enamel rod and interrod formation in one- and three-week renal transplanted teeth respectively. Thus, our results suggested that Fubp1 plays a modulating role during dentinogenesis and amelogenesis by regulating the expression pattern of signalling molecules to achieve the proper structural formation of hard tissue matrices and crown morphogenesis in mice molar development.

Effects of oleanolic acid acetate on bone formation in an experimental periodontitis model in mice.

OBJECTIVE: We evaluated the role of oleanolic acid acetate (OAA), a triterpenoid commonly used in the treatment of liver disorders, inflammatory diseases, and metastasis, in bone formation after tooth loss by periodontitis. BACKGROUND: Periodontitis causes the sequential degradation of the alveolar bone and associated structures, resulting in tooth loss. Several studies have attempted to regenerate the bone for implantation following tooth loss. METHODS: Maxillary left second molar was extracted from 8-week-old male mice following induction of periodontitis by ligature for 5 days. The extraction socket was treated with 50 ng/µL OAA for 1, 2, and 3 weeks. Detailed morphological changes were examined using Masson's trichrome staining, and the precise localization patterns of various signaling molecules, including CD31, F4/80, interleukin (IL)-6, and osteocalcin, were observed. The volume of bone formation was examined by Micro-CT. Osteoclasts were enumerated using tartrate-resistant acid phosphatase (TRAP) staining. For molecular dissection of signaling molecules, we employed the hanging-drop in vitro cultivation method at E14 for 1 day and examined the expression pattern of transforming growth factor (TGF)-ß superfamily and Wnt signaling genes. RESULTS: Histomorphometrical examinations showed facilitated bone formation in the extraction socket following OAA treatment. In addition, OAA-treated specimens showed the altered localization patterns of inflammatory and bone formation-related signaling molecules including CD31, F4/80, IL-6, and osteocalcin. Also, embryonic tooth germ mesenchymal tissue cultivation with OAA treatment showed the significant altered expression patterns of signaling molecules such as transforming growth factor (TGF)-ß superfamily and Wnt signaling. CONCLUSIONS: Oleanolic acid acetate induces bone formation and remodeling through proper modulation of osteoblast, osteoclast, and inflammation with regulations of TGF-ß and Wnt signaling.

Effects of vascular formation during alveolar bone process morphogenesis in mice.

The alveolar bone process is the thickened ridge of bone that bears the teeth and is known to have dynamic functional interactions with surrounding tissues. However, the detailed morphological changes that occur during alveolar bone process development and the underlying molecular mechanisms behind this morphogenesis have not been elucidated. In this study, we examined the detailed morphological changes of the alveolar bone process during mouse development using HE and MTC staining. In addition, we evaluated the precise localization pattern of various signaling molecules involved in blood vessel formation including CD31, α-SMA, VEGF, periostin, and TGF-ß. Innervation of the alveolar bone process was examined following injection of the nerve terminal dye AM1-43. The morphological and immunohistochemical data suggested that there is an intimate relationship between alveolar bone process development and blood vessel formation. To more closely examine the role of blood vessels in alveolar bone process formation, we microinjected mice with a clinically available anti-VEGF antibody, bevacizumab, at PN5 and analyzed the effects 5 days later. Compared to the control animals, anti-VEGF treated animals showed a disruption of the integration of bony tissues to form the alveolar bone process structures, which should contain the periodontal ligaments. Based on these data, we conclude that specific morphogenesis of the alveolar bone process is closely associated with blood vessel formation.

Radiopacity for Contemporary Luting Cements Using Digital Radiography under Various Exposure Conditions.

PURPOSE: This study examined the radiopacity of contemporary luting cements using direct digital radiography under a range of exposure conditions. MATERIALS AND METHODS: Disc specimens (N = 80, n = 10 per group, ø5 mm × 1 mm) were prepared from 8 resin-based luting cements (BisCem Clearfil SA Luting, Duolink, Maxcem Elite Multilink Speed, Panavia F 2.0, RelyX Unicem Clicker, V-link). The specimens were radiographed using a charge-coupled device sensor along with an 11-step aluminum step wedge (1.5-mm incremental steps) and 1-mm-thick tooth cut using five tube voltage/exposure time setups (60 kVp, 0.10/0.08 seconds; 70 kVp, 0.10/0.08/0.06 seconds) at 4 mA and 30 cm. The radiopacity of the specimens was compared with that of the aluminum step wedge and human enamel and dentin using NIH ImageJ software (available at http://rsb.info.nih.gov/ij/). A linear regression model for the aluminum step wedge was constructed, and the data were analyzed by ANOVA and Duncan post hoc test. RESULTS: Maxcem Elite (5.142 to 5.441) showed the highest radiopacity of all materials, followed in order by Multilink Speed (3.731 to 3.396) and V-link (2.763 to 3.103). The radiopacity of Panavia F 2.0 (2.025 to 2.429), BisCem (1.825 to 2.218), Clearfil SA Luting (1.692 to 2.145), Duolink (1.707 to 1.993), and RelyX Unicem Clicker (1.586 to 1.979) were between enamel (2.117 to 2.330) and dentin (1.302 to 1.685). The radiopacity of 70 kVp conditions was higher than that of the 60 kVp conditions. CONCLUSIONS: The radiopacities of the tested luting materials were greater than those of dentin or aluminum, satisfying the criteria of the International Organization for Standardization, and they differed significantly from each other in the exposure setups.

Prohibitin modulates periodontium differentiation in mice development.

Introduction: Prohibitin (PHB) is an essential scaffold protein that modulates signaling pathways controlling cell survival, metabolism, inflammation, and bone formation. However, its specific role in periodontium development remains less understood. This study aims to elucidate the expression pattern and function of PHB in periodontium development and its involvement in alveolar bone formation. Methods: Immunolocalization of PHB in the periodontium of postnatal (PN) mice were examined. Phb morpholino was micro-injected into the right-side mandible at PN5, corresponding to the position where the alveolar bone process forms in relation to the lower first molar. The micro-injection with a scramble control (PF-127) and the left-side mandibles were used as control groups. Five days post-micro-injection, immunohistochemical analysis and micro-CT evaluation were conducted to assess bone mass and morphological changes. Additionally, expression patterns of signaling molecules were examined following Phb downregulation using 24-h in vitro cultivation of developing dental mesenchyme at E14.5. Results: The immunostaining of PHB showed its localization in the periodontium at PN5, PN8, and PN10. The in vitro cultivation of dental mesenchyme resulted in alterations in Bmps, Runx2, and Wnt signalings after Phb knock-down. At 5 days post-micro-injection, Phb knocking down showed weak immunolocalizations of runt-related transcription factor (RUNX2) and osteocalcin (OCN). However, knocking down Phb led to histological alterations characterized by decreased bone mass and stronger localizations of Ki67 and PERIOSTIN in the periodontium compared 1 to control groups. The micro-CT evaluation showed decreased bone volume and increased PDL space in the Phb knock-down specimens, suggesting its regulatory role in bone formation. Discussion: The region-specific localization of PHB in the margin where alveolar bone forms suggests its involvement in alveolar bone formation and the differentiation of the periodontal ligament. Overall, our findings suggest that Phb plays a modulatory role in alveolar bone formation by harmoniously regulating bone-forming-related signaling molecules during periodontium development.

Comparison of carotid artery calcification between stroke and nonstroke patients using CT angiographic and panoramic images.

OBJECTIVES: This study aimed to analyze the characteristics of carotid artery calcification (CAC) in stroke and nonstroke patients using computed tomography angiographic (CTA) and panoramic images. METHODS: This is a retrospective study on patients who acquired both CTA and panoramic images at the Neurology Department of Kyungpook National University Hospital, Daegu, South Korea, between 2011 and 2016. The patients were divided into stroke (n = 109) and nonstroke (n = 355) groups based on the final diagnosis. CAC was analyzed in each group based on its presence, shape, and severity using the [Formula: see text]2 test. The differences in age and sex between the two groups were examined using a two-sample t-test. A measure of intraobserver reliability was obtained using Cohen's κ index. RESULTS: CAC was more frequently observed in the stroke group than in the nonstroke group using both CTA (stroke group, 100%; nonstroke group, 23.1%) and panoramic (stroke group, 83.5%; nonstroke group, 16.6%) images. Although scattered CAC shape and mild severity occupied the largest portion in both groups, vessel-outlined CAC was more common in nonstroke patients than in stroke patients. In age and sex analyses, only females patients in their 70 s showed significant differences in CAC shape between the stroke and nonstroke groups. CONCLUSIONS: On both CTA and panoramic images, although CAC is found more frequently in the stroke group, vessel-outlined-shaped CAC in the nonstorke group shows significant differences compared to other shapes.

Analysis of the fluid contents of simple bone cyst in the mandible.

Description of simple bone cyst (SBC) content has been controversial. This study aimed to assess and give a clearer picture of the SBC cavity contents. Between 2014 and 2016, 19 patients with SBC verified by histopathological examination were included in this study. SBC cavity content was investigated using clinical, radiographic, surgical, and laboratory findings. The difference in components among cavity fluid, blood, and serum was evaluated using a paired sample t-test for statistical analysis. All 19 SBC cases radiographically and surgically revealed a fluid-filled cavity. The patients' average age was 21.3 ± 13.2 years, with no sex predominance found. SBCs were found mostly in the anterior mandible (n = 12, 63.2%). All lesions were filled with clear straw-colored or blood-colored floods with low concentration. Although the fluid components were similar to those in the blood and serum in the laboratory analysis, the statistical analysis revealed that the fluid components were not significantly different only for eosinophil (p = 0.43) and basophil (p = 0.06) counts as blood components and sodium (p = 0.76), potassium (p = 0.08), and chloride (p = 0.13) concentration as serum components. The results show that SBC is a fluid-filled cavity, with the cavity fluid being more likely similar to serum rather than blood regarding internal components.

Giant lipoma of the tongue: A case report and review of the literature.

This report presents the case of a 49-year-old man who presented with giant masses that had recently grown on the bilateral sides of the tongue. A clinical examination revealed rubbery yellowish lesions protruding from the tongue. A panoramic radiograph showed an enlarged soft tissue shadow of the tongue. Computed tomography showed well-defined circumscribed mass exhibiting a homogeneous low density on the bilateral sides of the tongue. On magnetic resonance images, the masses showed a high signal intensity on T1-weighted images and iso-signal intensity with partially hyperintense margin on fat-suppressed T2-weighted images. Surgical excision was performed, and a histopathologic examination confirmed the diagnosis of lipoma. The patient recovered well with no sign of recurrence. A giant lipoma is defined as a lipoma larger than 5 cm in diameter. A literature review of giant lipomas of the tongue is also presented herein.

Facilitation of Reparative Dentin Using a Drug Repositioning Approach With 4-Phenylbutric Acid.

For hard tissue formation, cellular mechanisms, involved in protein folding, processing, and secretion play important roles in the endoplasmic reticulum (ER). In pathological and regeneration conditions, ER stress hinders proper formation and secretion of proteins, and tissue regeneration by unfolded protein synthesis. 4-Phenylbutyric acid (4PBA) is a chemical chaperone that alleviates ER stress through modulation in proteins folding and protein trafficking. However, previous studies about 4PBA only focused on the metabolic diseases rather than on hard tissue formation and regeneration. Herein, we evaluated the function of 4PBA in dentin regeneration using an exposed pulp animal model system via a local delivery method as a drug repositioning strategy. Our results showed altered morphological changes and cellular physiology with histology and immunohistochemistry. The 4PBA treatment modulated the inflammation reaction and resolved ER stress in the early stage of pulp exposure. In addition, 4PBA treatment activated blood vessel formation and TGF-ß1 expression in the dentin-pulp complex. Micro-computed tomography and histological examinations confirmed the facilitated formation of the dentin bridge in the 4PBA-treated specimens. These results suggest that proper modulation of ER stress would be an important factor for secretion and patterned formation in dentin regeneration.

Gene profiling in dorso-ventral patterning of mouse tongue development.

BACKGROUND: The tongue is a muscular fleshy organ in the oral cavity that is anatomically divided into the dorsal, ventral, anterior, and posterior part. The intricate tissue organisation and diverse origins of the tongue make it a complex organ of the oral cavity. OBJECTIVES: To reveal the signalling molecules involved in the formation of the dorsal and ventral parts of the tongue through microarray analysis. METHODS: Dorsal and ventral tongue tissues were isolated from embryonic day 14 mice by micro-dissection. RNA was extracted from the dorsal and ventral tongue tissues separately for microarray analysis. Microarray data were confirmed by quantitative reverse transcription polymerase chain reaction and whole-mount in situ hybridisation. RESULTS: Microarray analysis revealed expression of 33,793 genes. Of these, 931 genes were found to be equally expressed in both the dorsal and ventral parts of the tongue. On limiting the fold-change cut-off to over 1.5-fold, 725 genes were expressed over 1.5-fold in the ventral part and 1,672 in the dorsal part of the tongue. The qPCR and whole-mount in situ hybridisation revealed the expressions of angiopoietin 2 (Angpt2), fibroblast growth factor 18 (Fgf18), mesenchyme homeobox gene1 (Meox1), and SPARC-related modular calcium binding 2 (Smoc2) in the ventral part of the tongue. CONCLUSIONS: Numerous signalling molecules can be selected from our microarray results to examine their roles in tongue development and disease model systems. In the near future, the selection of candidate genes and their functional evaluations will be performed through loss- and gain-of-function mutation studies.

The effects of 4-Phenylbutyric acid on ER stress during mouse tooth development.

Introduction: During tooth development, proper protein folding and trafficking are significant processes as newly synthesized proteins proceed to form designated tissues. Endoplasmic reticulum (ER) stress occurs inevitably in tooth development as unfolded and misfolded proteins accumulate in ER. 4-Phenylbutyric acid (4PBA) is a FDA approved drug and known as a chemical chaperone which alleviates the ER stress. Recently, several studies showed that 4PBA performs therapeutic effects in some genetic diseases due to misfolding of proteins, metabolic related-diseases and apoptosis due to ER stress. However, the roles of 4PBA during odontogenesis are not elucidated. This study revealed the effects of 4PBA during molar development in mice. Methods: We employed in vitro organ cultivation and renal transplantation methods which would mimic the permanent tooth development in an infant period of human. The in vitro cultivated tooth germs and renal calcified teeth were examined by histology and immunohistochemical analysis. Results and Discussion: Our results revealed that treatment of 4PBA altered expression patterns of enamel knot related signaling molecules, and consequently affected cellular secretion and patterned formation of dental hard tissues including dentin and enamel during tooth morphogenesis. The alteration of ER stress by 4PBA treatment during organogenesis would suggest that proper ER stress is important for pattern formation during tooth development and morphogenesis, and 4PBA as a chemical chaperone would be one of the candidate molecules for dental and hard tissue regeneration.

Effects of erythropoietin on osteoblast in the tooth extraction socket in mice periodontitis model.

Periodontitis is an excessive inflammatory event in tooth-supporting tissues and can cause tooth loss. We used erythropoietin (EPO), which has been reported to play an important role in bone healing and modulation of angiogenesis, as a therapeutic agent in vivo and in vitro experimental models to analyze its effect on periodontitis. First, EPO was applied to in vitro MC3T3-E1 cells and human periodontal ligament fibroblast (hPDLF) cells to examine its function in altered cellular events and gene expression patterns. In vitro cultivation of MC3T3-E1 and hPDLF cells with 10 IU/ml EPO at 24 and 48 h showed an obvious increase in cell proliferation. Interestingly, EPO treatment altered the expression of osteogenesis-related molecules, including alkaline phosphatase (ALP), bone morphogenetic protein-2 (BMP-2), and osteocalcin (OC) in MC3T3-E1 cells but not in hPDLF cells. In particular, MC3T3-E1 cells showed increased expression of ALP, BMP-2, and OC on day 5, while hPDLF cells showed increased expression of BMP-2, and OC on day 14. Based on the in vitro examination, we evaluated the effect of EPO on bone formation using an experimentally-induced animal periodontitis model. After the induction of periodontitis in the maxillary left second M, 10 IU/ml of EPO was locally applied to the extraction tooth sockets. Histomorphological examination using Masson's trichrome (MTC) staining showed facilitated bone formation in the EPO-treated groups after 14 days. Similarly, stronger positive reactions against vascular endothelial growth factor (VEGF), cluster of differentiation 31 (CD31), runt-related transcription factor 2 (RUNX2), and osteocalcin (OC) were detected in the EPO-treated group compared to the control. Meanwhile, myeloperoxidase, an inflammatory marker, was decreased in the EPO-treated group on days 1 and 5. Overall, EPO facilitates bone healing and regeneration through altered signaling regulation and modulation of inflammation in the osteoblast cell lineage and to a lesser extent in hPDLF cells.

Recurrent benign cementoblastoma: A case report and literature review.

A 16-year-old male presented with pain in the right posterior mandible on chewing that had lasted for several months. The radiographic features of the lesion included a radiolucent-radiopaque mixed-density mass with a radiolucent rim attached to the root of the mandibular right first molar. The preliminary radiographic diagnosis was benign cementoblastoma, which was confirmed by histopathological examination following surgical excision. The lesion recurred 3 years after treatment; radiographically, it consisted of 3 round foci with mixed radiopacity, each with a radiolucent rim near the root of the mandibular right second premolar and the edentulous postoperative region. The lesion was diagnosed as recurrent benign cementoblastoma and a second surgery was scheduled. This report presented an unusual case of recurrent benign cementoblastoma following surgical excision and extraction of the involved tooth, along with a literature review on reported cases of recurrent benign cementoblastoma with a focus on its clinical features and the best treatment options.

Facilitating Reparative Dentin Formation Using Apigenin Local Delivery in the Exposed Pulp Cavity.

Apigenin, a natural product belonging to the flavone class, affects various cell physiologies, such as cell signaling, inflammation, proliferation, migration, and protease production. In this study, apigenin was applied to mouse molar pulp after mechanically pulpal exposure to examine the detailed function of apigenin in regulating pulpal inflammation and tertiary dentin formation. In vitro cell cultivation using human dental pulp stem cells (hDPSCs) and in vivo mice model experiments were employed to examine the effect of apigenin in the pulp and dentin regeneration. In vitro cultivation of hDPSCs with apigenin treatment upregulated bone morphogenetic protein (BMP)- and osteogenesis-related signaling molecules such as BMP2, BMP4, BMP7, bone sialoprotein (BSP), runt-related transcription factor 2 (RUNX2), and osteocalcin (OCN) after 14 days. After apigenin local delivery in the mice pulpal cavity, histology and cellular physiology, such as the modulation of inflammation and differentiation, were examined using histology and immunostainings. Apigenin-treated specimens showed period-altered immunolocalization patterns of tumor necrosis factor (TNF)-α, myeloperoxidase (MPO), NESTIN, and transforming growth factor (TGF)-ß1 at 3 and 5 days. Moreover, the apigenin-treated group showed a facilitated dentin-bridge formation with few irregular tubules after 42 days from pulpal cavity preparation. Micro-CT images confirmed obvious dentin-bridge structures in the apigenin-treated specimens compared with the control. Apigenin facilitated the reparative dentin formation through the modulation of inflammation and the activation of signaling regulations. Therefore, apigenin would be a potential therapeutic agent for regenerating dentin in exposed pulp caused by dental caries and traumatic injury.