Yue Cai, Xue-xin Tan, Li Zhao, Ran Zhang, Tong Zhu, Yang Du, Xukai Wang
{"title":"Withdrawal: Synthesis of a Novel bFGF/nHAP/COL Bone Tissue Engineering Scaffold for Mandibular Defect Regeneration in a Rabbit Model [Journal of Hard Tissue Biology 27(1) Vol.27, 2018, pp 85-94]","authors":"Yue Cai, Xue-xin Tan, Li Zhao, Ran Zhang, Tong Zhu, Yang Du, Xukai Wang","doi":"10.2485/jhtb.31.61","DOIUrl":"https://doi.org/10.2485/jhtb.31.61","url":null,"abstract":"","PeriodicalId":16040,"journal":{"name":"Journal of Hard Tissue Biology","volume":"1 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68966479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Inhibitory Effects of Resveratrol on Inflammatory Response in Rat Dental Pulp","authors":"L. Hu, Hao Shen, Shiliang Guo","doi":"10.2485/jhtb.31.135","DOIUrl":"https://doi.org/10.2485/jhtb.31.135","url":null,"abstract":"","PeriodicalId":16040,"journal":{"name":"Journal of Hard Tissue Biology","volume":"1 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68965997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Association of Peroxisome Proliferator-Activated Receptor Gamma 2 Gene Polymorphism with Susceptibility to Diabetic Periodontitis: Experience of a Tertiary Hospital in Fujian Province, China","authors":"Xiaohua Zeng, Cheng Chen","doi":"10.2485/jhtb.31.127","DOIUrl":"https://doi.org/10.2485/jhtb.31.127","url":null,"abstract":"","PeriodicalId":16040,"journal":{"name":"Journal of Hard Tissue Biology","volume":"15 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68965918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fumitaka Yoshino, Rina Sasaki, Yuka Asada, K. Shiozaki, S. Shimoda, Takatsugu Yamamoto
In this study, we immersed amorphous calcium phosphate (ACP) powder in biochemical buffer solutions and performed analysis of its solubility and phase transformation of the precipitate. After preparing ACP powder that contains no impurities, we used 4-(2-hydroxyethyl)-1-piperazinetethanesulfonic acid (HEPES) buffer, one of the good buffers, as a buffer solution and measured the amount of calcium ions eluted from ACP and other calcium phosphate crystals. ACP was immersed in the buffer solution at 5°C, 20°C, and 37°C, and the amount of eluted calcium ions was measured from 15 min to 24 h thereafter. The precipitated solid phase was analyzed using X-ray diffraction and its morphology was observed using transmission electron microscopy. The precipitation of hydroxyapatite (HAp) was observed after 15 min in HEPES buffer solution. Furthermore, in this experimental group, the precipitates of the sample incubated in HEPES buffer solution at 37°C for 24 h produced the largest HAp crystals. From these results we concluded that ACP immersed in HEPES buffer solution easily releases calcium ions and phosphate ions, and a rapid phase transformation to HAp occurs. Moreover, we assume that, in addition to the thermodynamic effect, the crystal growth of HAp is enhanced by the buffer solution.
{"title":"Studies on Change in Solubility over Time of the Bioactive Material Amorphous Calcium Phosphate and Precipitation of Hydroxyapatite","authors":"Fumitaka Yoshino, Rina Sasaki, Yuka Asada, K. Shiozaki, S. Shimoda, Takatsugu Yamamoto","doi":"10.2485/jhtb.31.1","DOIUrl":"https://doi.org/10.2485/jhtb.31.1","url":null,"abstract":"In this study, we immersed amorphous calcium phosphate (ACP) powder in biochemical buffer solutions and performed analysis of its solubility and phase transformation of the precipitate. After preparing ACP powder that contains no impurities, we used 4-(2-hydroxyethyl)-1-piperazinetethanesulfonic acid (HEPES) buffer, one of the good buffers, as a buffer solution and measured the amount of calcium ions eluted from ACP and other calcium phosphate crystals. ACP was immersed in the buffer solution at 5°C, 20°C, and 37°C, and the amount of eluted calcium ions was measured from 15 min to 24 h thereafter. The precipitated solid phase was analyzed using X-ray diffraction and its morphology was observed using transmission electron microscopy. The precipitation of hydroxyapatite (HAp) was observed after 15 min in HEPES buffer solution. Furthermore, in this experimental group, the precipitates of the sample incubated in HEPES buffer solution at 37°C for 24 h produced the largest HAp crystals. From these results we concluded that ACP immersed in HEPES buffer solution easily releases calcium ions and phosphate ions, and a rapid phase transformation to HAp occurs. Moreover, we assume that, in addition to the thermodynamic effect, the crystal growth of HAp is enhanced by the buffer solution.","PeriodicalId":16040,"journal":{"name":"Journal of Hard Tissue Biology","volume":"1 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68965873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Le Wang, Xingqiang Wang, Rui Liang, Shusen Wang, Jinglin Cao
{"title":"A Comparison of Mesenchymal Stem Cells from Human Adipose Tissues by Resection and by Liposuction","authors":"Le Wang, Xingqiang Wang, Rui Liang, Shusen Wang, Jinglin Cao","doi":"10.2485/jhtb.31.15","DOIUrl":"https://doi.org/10.2485/jhtb.31.15","url":null,"abstract":"","PeriodicalId":16040,"journal":{"name":"Journal of Hard Tissue Biology","volume":"59 11 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68966064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: The aim of this study was to identify genes that are prominently expressed in rat bone marrow cell-derived osteoblasts during the initial phase of low-intensity pulsed ultrasound (LIPUS) exposure. Bone marrow cells were obtained from three Sprague-Dawley rats (8-week-old, male), and cell cultures were prepared by suspension in osteogenic medium. After cultures were established, test cultures were exposed to LIPUS from the bottom of the cell culture plate for 15 min/d on days 1–4 (LIPUS group). LIPUS signals were transmitted at a frequency of 3 MHz and a spatial average intensity of 40 mW/cm 2 . The control group was not exposed to LIPUS. On day 14, alizarin red S staining was performed to detect calcifi -cation. On day 4, total RNA was extracted from both cultures, hybridized to microarray slides, and the resulting data set was analyzed. Genes exhibiting a fold-change ≥2 and a p-value <0.05 (LIPUS vs. control) were identified as differentially expressed genes. Pathway analysis was performed on genes whose expression increased in the LIPUS group. The cellular areas stained with alizarin red S were significantly larger in the LIPUS group than in the control group on day 14. LIPUS exposure increased the expression of genes related to type II interferon signaling, and endochondral ossification was ob served after 4 d of culture. The results demonstrated that LIPUS exposure activated the immune response and promoted osteoblast differentiation.
本研究的目的是鉴定在低强度脉冲超声(LIPUS)暴露初始阶段在大鼠骨髓细胞来源的成骨细胞中显著表达的基因。取3只8周龄雄性Sprague-Dawley大鼠骨髓细胞，在成骨培养基中悬浮培养细胞。培养完成后，在第1-4天(LIPUS组)将实验培养物从细胞培养板底部暴露于LIPUS中15 min/d。LIPUS信号以3 MHz的频率和40 mW/ cm2的空间平均强度传输。对照组不使用LIPUS。第14天，茜素红S染色检测钙化。第4天，从两个培养物中提取总RNA，将其杂交到微阵列载玻片上，并分析结果数据集。fold-change≥2且p值<0.05 (LIPUS vs. control)的基因被鉴定为差异表达基因。对LIPUS组中表达增高的基因进行通路分析。第14天，LIPUS组茜素红S染色的细胞面积明显大于对照组。LIPUS暴露增加了II型干扰素信号相关基因的表达，培养4 d后观察到软骨内成骨。结果表明，LIPUS暴露激活了免疫反应，促进了成骨细胞的分化。
{"title":"Gene Expression in Early Stages of Low-Intensity Pulsed Ultrasound Exposure on Bone Marrow Cells","authors":"Daisuke Yamaguchi, Kazuo Takeuchi, Atsuko Ueno, Masataka Yamaguchi, H. Murakami, Suguru Kimoto","doi":"10.2485/jhtb.31.23","DOIUrl":"https://doi.org/10.2485/jhtb.31.23","url":null,"abstract":": The aim of this study was to identify genes that are prominently expressed in rat bone marrow cell-derived osteoblasts during the initial phase of low-intensity pulsed ultrasound (LIPUS) exposure. Bone marrow cells were obtained from three Sprague-Dawley rats (8-week-old, male), and cell cultures were prepared by suspension in osteogenic medium. After cultures were established, test cultures were exposed to LIPUS from the bottom of the cell culture plate for 15 min/d on days 1–4 (LIPUS group). LIPUS signals were transmitted at a frequency of 3 MHz and a spatial average intensity of 40 mW/cm 2 . The control group was not exposed to LIPUS. On day 14, alizarin red S staining was performed to detect calcifi -cation. On day 4, total RNA was extracted from both cultures, hybridized to microarray slides, and the resulting data set was analyzed. Genes exhibiting a fold-change ≥2 and a p-value <0.05 (LIPUS vs. control) were identified as differentially expressed genes. Pathway analysis was performed on genes whose expression increased in the LIPUS group. The cellular areas stained with alizarin red S were significantly larger in the LIPUS group than in the control group on day 14. LIPUS exposure increased the expression of genes related to type II interferon signaling, and endochondral ossification was ob served after 4 d of culture. The results demonstrated that LIPUS exposure activated the immune response and promoted osteoblast differentiation.","PeriodicalId":16040,"journal":{"name":"Journal of Hard Tissue Biology","volume":"1 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68966392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Kobayashi, Haruka Takahashi, Kensuke Igarashi, Hiroki Katagiri, M. Haga-Tsujimura, I. Ogura, K. Nakahara, A. Tanaka
: In 2014, the American Association of Oral and Maxillofacial Surgery (AAOMS) recommended surgical treatment for medication-related osteonecrosis of the jaw (MRONJ) patients classified as Stage 3. In 2016, the Japanese position pa per recommended surgical treatment classified as Stage 2. Some systematic review reported effectiveness of surgical treat ment for MRONJ. However there is no concerted consciousness on the treatment methods of MRONJ patients in the pres-ent. This study aimed to retrospectively elucidate clinical outcomes of the surgical treatment of MRONJ patients under the same criteria. This study included 86 patients in 40 osteoporosis patients (5 men and 35 women, average age: 78.8 years) and 46 cancer patients (18 men and 28 women, average age: 67.7 years). The outcome was classified into two categories: Healing or No healing in each stage. Among 86 patients, MRONJ was found in 91 jaws, of which 69 jaws (75.8%) were surgically operated. Total healing rate of surgical treatment was 85.5%, and total healing rate of conservative treatment was 4.5%. It was suggested that surgical treatment for MRONJ had a high clinical response rate in all stages.
{"title":"Prognosis of Medication-Related Osteonecrosis of the Jaw with Surgical Treatment","authors":"E. Kobayashi, Haruka Takahashi, Kensuke Igarashi, Hiroki Katagiri, M. Haga-Tsujimura, I. Ogura, K. Nakahara, A. Tanaka","doi":"10.2485/jhtb.31.39","DOIUrl":"https://doi.org/10.2485/jhtb.31.39","url":null,"abstract":": In 2014, the American Association of Oral and Maxillofacial Surgery (AAOMS) recommended surgical treatment for medication-related osteonecrosis of the jaw (MRONJ) patients classified as Stage 3. In 2016, the Japanese position pa per recommended surgical treatment classified as Stage 2. Some systematic review reported effectiveness of surgical treat ment for MRONJ. However there is no concerted consciousness on the treatment methods of MRONJ patients in the pres-ent. This study aimed to retrospectively elucidate clinical outcomes of the surgical treatment of MRONJ patients under the same criteria. This study included 86 patients in 40 osteoporosis patients (5 men and 35 women, average age: 78.8 years) and 46 cancer patients (18 men and 28 women, average age: 67.7 years). The outcome was classified into two categories: Healing or No healing in each stage. Among 86 patients, MRONJ was found in 91 jaws, of which 69 jaws (75.8%) were surgically operated. Total healing rate of surgical treatment was 85.5%, and total healing rate of conservative treatment was 4.5%. It was suggested that surgical treatment for MRONJ had a high clinical response rate in all stages.","PeriodicalId":16040,"journal":{"name":"Journal of Hard Tissue Biology","volume":"1 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68966464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Miyazawa, Takeo Sekiya, Misuzu Kawaguchi, Yuji Kojima, M. Tabuchi, Takuma Sato, T. Kawai, S. Goto
: Bone morphogenetic protein (BMP) is the only cytokine that induces heterotopic new bone. BMP has been classi-fied as a subfamily of the TGF superfamily. The most important and essential aspect for the clinical application of BMP is the replenishment and reinforcement of bone defects and fragile areas with new bone. However, it is difficult to ascertain long term clinical results. In this study, we examined the osteogenic potential in mouse femoral fascia of crude BMP ex-tracted from bovine bone that had been stored at room temperature for 25 years. The results showed vigorous osteogenesis. This study demonstrates the long-term stability of crude BMP. study, we examined the osteogenic potential of crude BMP (cBMP) ex-tracted from and the material exhibited vigorous This study reports the long-term stability of the cBMP osteogenic potential.
{"title":"Vigorous Osteoinductivity Observed in Crude Bone Morphogenetic Protein Stored for 25 Years after Extraction at Room Temperature","authors":"K. Miyazawa, Takeo Sekiya, Misuzu Kawaguchi, Yuji Kojima, M. Tabuchi, Takuma Sato, T. Kawai, S. Goto","doi":"10.2485/jhtb.31.253","DOIUrl":"https://doi.org/10.2485/jhtb.31.253","url":null,"abstract":": Bone morphogenetic protein (BMP) is the only cytokine that induces heterotopic new bone. BMP has been classi-fied as a subfamily of the TGF superfamily. The most important and essential aspect for the clinical application of BMP is the replenishment and reinforcement of bone defects and fragile areas with new bone. However, it is difficult to ascertain long term clinical results. In this study, we examined the osteogenic potential in mouse femoral fascia of crude BMP ex-tracted from bovine bone that had been stored at room temperature for 25 years. The results showed vigorous osteogenesis. This study demonstrates the long-term stability of crude BMP. study, we examined the osteogenic potential of crude BMP (cBMP) ex-tracted from and the material exhibited vigorous This study reports the long-term stability of the cBMP osteogenic potential.","PeriodicalId":16040,"journal":{"name":"Journal of Hard Tissue Biology","volume":"1 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68966419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qingchao Wu, I. Yamawaki, Y. Taguchi, Kei Shiomi, Daisuke Kimura, Tsurayuki Takahashi, M. Umeda
Patients with diabetes mellitus (DM) are at an increased risk of tooth loss compared to healthy individuals. Although studies human subjects suggest that diabetes control is affected by periodontitis, there is scarce mechanistic evidence supporting its biological plausibility. Therefore, using type 2 DM rat bone marrow mesenchymal stromal cells (BMMSCs) were incubated with four concentrations of glucose (5.5, 8.0, 12.0 or 24.0 mM), the effects of different glucose concentrations on BMMSCs stemness and osteogenesis were evaluated. High glucose concentrations decreased the fluorescence intensity of β-actin, STRO-1, CD73 and CD90. Moreover, cell proliferation decreased at high glucose concentrations. Alkaline phosphatase activity was decreased at 12.0 mM and 24.0 mM. In contrast, osteocalcin production and calcium deposition were considerably increased at 24.0 mM. Differences in the calcium/phosphate ratio associated with various glucose concentrations were similar to calcium deposition. The mRNA expression of Runx2 and inflammatory cytokines increased with increasing glucose concentration. The RANKL/OPG ratio decreased at high glucose concentrations. A high glucose concentration increased hard tissue formation, but the quality and stemness of the mineralized tissue decreased. Thus, hard tissue had a high risk of bone resorption in the case of uncontrolled diabetes even if periodontal treatment stabilized state of periodontitis for a moment.
{"title":"Glucose Affects the Quality and Properties of Hard Tissue in Diabetes Mellitus Model","authors":"Qingchao Wu, I. Yamawaki, Y. Taguchi, Kei Shiomi, Daisuke Kimura, Tsurayuki Takahashi, M. Umeda","doi":"10.2485/jhtb.31.29","DOIUrl":"https://doi.org/10.2485/jhtb.31.29","url":null,"abstract":"Patients with diabetes mellitus (DM) are at an increased risk of tooth loss compared to healthy individuals. Although studies human subjects suggest that diabetes control is affected by periodontitis, there is scarce mechanistic evidence supporting its biological plausibility. Therefore, using type 2 DM rat bone marrow mesenchymal stromal cells (BMMSCs) were incubated with four concentrations of glucose (5.5, 8.0, 12.0 or 24.0 mM), the effects of different glucose concentrations on BMMSCs stemness and osteogenesis were evaluated. High glucose concentrations decreased the fluorescence intensity of β-actin, STRO-1, CD73 and CD90. Moreover, cell proliferation decreased at high glucose concentrations. Alkaline phosphatase activity was decreased at 12.0 mM and 24.0 mM. In contrast, osteocalcin production and calcium deposition were considerably increased at 24.0 mM. Differences in the calcium/phosphate ratio associated with various glucose concentrations were similar to calcium deposition. The mRNA expression of Runx2 and inflammatory cytokines increased with increasing glucose concentration. The RANKL/OPG ratio decreased at high glucose concentrations. A high glucose concentration increased hard tissue formation, but the quality and stemness of the mineralized tissue decreased. Thus, hard tissue had a high risk of bone resorption in the case of uncontrolled diabetes even if periodontal treatment stabilized state of periodontitis for a moment.","PeriodicalId":16040,"journal":{"name":"Journal of Hard Tissue Biology","volume":"1 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68966460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nobue Kikuchi, Kei Kitamura, N. Kasahara, Yudai Ogawa, N. Ishikawa, Masahito Yamamoto, Hitoshi Yamamoto
: Epithelial projections (EP), which form as Hertwig’s epithelial root sheath (HERS) extends, play an important role in the formation of multi-rooted teeth. However, three-dimensional (3D) observations of the process in which EP form the furcation area have not yet been conducted. To investigate the formation of the furcation area by EP, we used a 3D reconstruction model of the furcation area in rats, which form subpulpal lobes in the same manner as humans, and examined the extent of cell division around the epithelium. Wistar rats between postnatal days 3-18 (PN3-18) (n=3/age) were fixed by the perfusion of 4% paraformaldehyde solution, and the maxillae were dissected out and decalcified. Tissues were embed ded in paraffin by the conventional protocol, and 5-µm-thick serial sections and some sections for immunohistochemistry using an anti-proliferating cell nuclear antigen antibody of the frontal plane were prepared. All serial sections were stained by hematoxylin and eosin, and the structures of HERS, EP, dentin projections, and subpulpal lobes were overlayed after de-lineation every 5 sections from the images obtained of the maxillary second molar for the 3D reconstruction using ITK-snap software. Reconstructed images showed that a portion of HERS in the cervical region had extended into the dental papilla on PN3 to form EP. Four EP formed and extended with age at different speeds. On PN11, EP fused with one another in the center of the dental papilla and started to form subpulpal lobes. During this process, apical elongation in the apical direction of EP was not observed. Significant cell proliferation was detected in the dental papilla around the epithelium of the cervical loop. Collectively, these results indicate that the subpulpal lobes form immediately after the fusion of EP, and HERS extend in the apical direction following the fusion of EP.
{"title":"Three-Dimensional Observation of the Furcation Area during Multi-Rooted Tooth Formation in Rat","authors":"Nobue Kikuchi, Kei Kitamura, N. Kasahara, Yudai Ogawa, N. Ishikawa, Masahito Yamamoto, Hitoshi Yamamoto","doi":"10.2485/jhtb.31.163","DOIUrl":"https://doi.org/10.2485/jhtb.31.163","url":null,"abstract":": Epithelial projections (EP), which form as Hertwig’s epithelial root sheath (HERS) extends, play an important role in the formation of multi-rooted teeth. However, three-dimensional (3D) observations of the process in which EP form the furcation area have not yet been conducted. To investigate the formation of the furcation area by EP, we used a 3D reconstruction model of the furcation area in rats, which form subpulpal lobes in the same manner as humans, and examined the extent of cell division around the epithelium. Wistar rats between postnatal days 3-18 (PN3-18) (n=3/age) were fixed by the perfusion of 4% paraformaldehyde solution, and the maxillae were dissected out and decalcified. Tissues were embed ded in paraffin by the conventional protocol, and 5-µm-thick serial sections and some sections for immunohistochemistry using an anti-proliferating cell nuclear antigen antibody of the frontal plane were prepared. All serial sections were stained by hematoxylin and eosin, and the structures of HERS, EP, dentin projections, and subpulpal lobes were overlayed after de-lineation every 5 sections from the images obtained of the maxillary second molar for the 3D reconstruction using ITK-snap software. Reconstructed images showed that a portion of HERS in the cervical region had extended into the dental papilla on PN3 to form EP. Four EP formed and extended with age at different speeds. On PN11, EP fused with one another in the center of the dental papilla and started to form subpulpal lobes. During this process, apical elongation in the apical direction of EP was not observed. Significant cell proliferation was detected in the dental papilla around the epithelium of the cervical loop. Collectively, these results indicate that the subpulpal lobes form immediately after the fusion of EP, and HERS extend in the apical direction following the fusion of EP.","PeriodicalId":16040,"journal":{"name":"Journal of Hard Tissue Biology","volume":"1 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68966114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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