Continuously growing incisors are common to all rodents, which include the Microtus genus of voles. However, unlike many rodents, voles also possess continuously growing molars. Here, we report spontaneous molar defec...Continuously growing incisors are common to all rodents, which include the Microtus genus of voles. However, unlike many rodents, voles also possess continuously growing molars. Here, we report spontaneous molar defects in a population of Prairie voles （Microtus ochrogaster）. We identified bilateral protuberances on the ventral surface of the mandible in several voles in our colony. In some cases, the protuberances broke through the cortical bone. The mandibular molars became exposed and infected, and the maxillary molars entered the cranial vault. Visualisation upon soft tissue removal and microcomputed tomography （microCT） analyses confirmed that the protuberances were caused by the overgrowth of the apical ends of the molar teeth. We speculate that the unrestricted growth of the molars was due to the misregulation of the molar dental stem cell niche. Further study of this molar phenotype may yield additional insight into stem cell regulation and the evolution and development of continuously growing teeth.展开更多
This case report describes the diagnosis and endodontic therapy of maxillary fused second and third molars, using cone-beam computed tomography （CBCT）. A 31-year-old Chinese male, with no contributory medical or fam...This case report describes the diagnosis and endodontic therapy of maxillary fused second and third molars, using cone-beam computed tomography （CBCT）. A 31-year-old Chinese male, with no contributory medical or family/social history, presented with throbbing pain in the maxillary right molar area following an unsuccessful attempted tooth extraction. Clinical examination revealed what appeared initially to be a damaged large extra cusp on the buccal aspect of the distobuccal cusp of the second molar. However, CBCT revealed that a third molar was fused to the second molar. Unexpectedly, the maxillary left third molar also was fused to the second molar, and the crown of an unerupted supernumerary fourth molar was possibly also fused to the apical root region of the second molar. Operative procedures should not be attempted without adequate radiographic investigation. CBCT allowed the precise location of the root canals of the right maxillary fused molar teeth to permit successful endodontic therapy, confirmed after 6 months.展开更多
Background: Taurodontism is one of the most significant deviations from the normal tooth morphology affecting the molars in both primary and permanent dentition. Taurodontism refers to the Enlargement of the pulp cham...Background: Taurodontism is one of the most significant deviations from the normal tooth morphology affecting the molars in both primary and permanent dentition. Taurodontism refers to the Enlargement of the pulp chamber, resulting in its bifurcation pushed toward the apex of a tooth’s root. This study evaluated the prevalence of Taurodontism from radiographs taken at the University of Ghana Dental School Oral Radiology Unit from January 2017 to December 2022. Methodology: In this cross-sectional study, panoramic and periapical radiographs of 1000 randomly selected patients who visited the Oral Radiology Unit from January 2017 to December 2022. Radiographs were evaluated for apically displaced pulp chamber. Data was statistically evaluated, and the chi-square test was employed to assess the prevalence of taurodontism in the upper and lower jaws (p Results: Taurodontism was found in 171 radiographs giving it a prevalence of 17.1% of which 57% (98 radiographs) were from females and 43% (73 radiographs) were from males. This finding was not significant (p > 0.05). Taurodontism occurred more in the maxilla (289 teeth, 80.7%) compared to the mandible molars (186 teeth, 64.3%) giving it a ratio of 1.6:1. This finding was highly significant (p Conclusion: Taurodontism is relatively common in the Ghanaian population affecting more females compared to males according to this study. Further studies using a large sample need to be carried out to determine its incidence in the general community.展开更多
目的:观察下颌阻生第三磨牙(impacted mandibular third molars,IM3Ms)拔除术后的自然转归及对邻近下颌第二磨牙(mandibular second molars,M2Ms)的影响。方法:选择下颌第三磨牙骨埋伏阻生的患者34例(51颗IM3Ms),使用超声骨刀、气动涡...目的:观察下颌阻生第三磨牙(impacted mandibular third molars,IM3Ms)拔除术后的自然转归及对邻近下颌第二磨牙(mandibular second molars,M2Ms)的影响。方法:选择下颌第三磨牙骨埋伏阻生的患者34例(51颗IM3Ms),使用超声骨刀、气动涡轮手机拔除患牙,分别于术前、术后1周及术后6个月随访,观察术后反应及M2Ms远中骨缺损情况。比较手术前后M2Ms远中骨缺损深度,并分析其影响因素。采用SPSS 29.0软件包对数据进行统计学分析。结果:术前M2Ms远中骨高度未见明显缺损,但拔除IM3Ms时,由于去骨拔牙等操作产生骨缺损。术后6个月,骨高度虽有所恢复,骨缺损率减少,但未达到术前水平。IM3Ms埋伏阻生深度是恢复率的主要影响因素。探诊深度较术前显著增加。术后24 h内患者疼痛感较重,术后1周缓解,但仍存在轻度开口受限及面部肿胀。拔除IM3Ms对患者日常生活、情绪、工作、睡眠影响较小。结论:下颌第三磨牙拔除术后,邻近第二磨牙远中骨高度部分恢复,但未达到术前水平。拔牙手术中需采取更加精细的手术技巧,以减少对邻近牙和骨组织的影响。同时,拔除IM3Ms后应给予镇痛药物,加强卫生宣教,提高患者术后舒适度。展开更多
目的 利用锥形束CT(cone beam computed technology,CBCT)分析下颌阻生第三磨牙(mandibular third molar,MTM)对第二磨牙(mandibular second molar,MSM)不同部位牙槽骨的影响,为临床MTM的拔除指征及MSM的诊断、治疗及预后提供理论依据...目的 利用锥形束CT(cone beam computed technology,CBCT)分析下颌阻生第三磨牙(mandibular third molar,MTM)对第二磨牙(mandibular second molar,MSM)不同部位牙槽骨的影响,为临床MTM的拔除指征及MSM的诊断、治疗及预后提供理论依据。方法 收集山西省人民医院口腔中心CBCT数据库中随机抽取18岁以上500例阻生MTM的CBCT图像,根据阻生深度及阻生角度分别确定PG及Winter分类,测量MTM与MSM釉牙骨质界之间(CEJ)的距离及第二磨牙颊侧、舌侧、近中、远中牙槽骨吸收的距离。采用Friedman秩和检验比较颊、舌、近中、远中牙槽骨吸收;采用非参数Kruskal Wallis检验、Mann-Whitney U检验分析不同阻生类型间牙槽骨吸收的差异;采用Spearman秩相关及多元线性回归分析各因素与牙槽骨吸收最大侧的关系。结果 远中牙槽骨吸收距离(distal alveolar bone loss of mandibular second molar,MSM-DBL)高于颊侧、舌侧及近中。在Winter分类中,牙槽骨吸收距离水平组最大,近中组次之,垂直组和远中组最小;在PG分类中,从低位、中位到高位牙槽骨吸收距离逐渐降低(P<0.001)。CEJ距离、阻生角度(11°~100°)以及阻生深度均为MSM-DBL的独立危险因素,前二者与MSM-DBL呈正相关(P<0.05)。本研究人群中,MSM-DBL男性高于女性(P<0.05),年龄与MSM-DBL不存在相关性(P>0.05)。结论 阻生MTM对MSM-DBL影响最大;CEJ距离、阻生角度、阻生深度、性别为MSM-DBL的影响因素。展开更多
基金funded by the National Institutes of Health through grants R00DE022059 to Andrew H JheonDP2-OD007191 and R01-DE021420 to Ophir Klein+3 种基金National Alliance for Research on Schizophrenia and Depression (NARSAD) grant to Devanand S ManoliDP1MH099900 to Nirao M Shahsupported by the Department of Health and Human Services/NIH S10 Shared Instrumentation Grant (S10RR026645)the Departments of Preventive and Restorative Dental Sciences and Orofacial Sciences, School of Dentistry, UCSF
文摘Continuously growing incisors are common to all rodents, which include the Microtus genus of voles. However, unlike many rodents, voles also possess continuously growing molars. Here, we report spontaneous molar defects in a population of Prairie voles （Microtus ochrogaster）. We identified bilateral protuberances on the ventral surface of the mandible in several voles in our colony. In some cases, the protuberances broke through the cortical bone. The mandibular molars became exposed and infected, and the maxillary molars entered the cranial vault. Visualisation upon soft tissue removal and microcomputed tomography （microCT） analyses confirmed that the protuberances were caused by the overgrowth of the apical ends of the molar teeth. We speculate that the unrestricted growth of the molars was due to the misregulation of the molar dental stem cell niche. Further study of this molar phenotype may yield additional insight into stem cell regulation and the evolution and development of continuously growing teeth.
基金the financial support received from A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (2011-137)
文摘This case report describes the diagnosis and endodontic therapy of maxillary fused second and third molars, using cone-beam computed tomography （CBCT）. A 31-year-old Chinese male, with no contributory medical or family/social history, presented with throbbing pain in the maxillary right molar area following an unsuccessful attempted tooth extraction. Clinical examination revealed what appeared initially to be a damaged large extra cusp on the buccal aspect of the distobuccal cusp of the second molar. However, CBCT revealed that a third molar was fused to the second molar. Unexpectedly, the maxillary left third molar also was fused to the second molar, and the crown of an unerupted supernumerary fourth molar was possibly also fused to the apical root region of the second molar. Operative procedures should not be attempted without adequate radiographic investigation. CBCT allowed the precise location of the root canals of the right maxillary fused molar teeth to permit successful endodontic therapy, confirmed after 6 months.
文摘Background: Taurodontism is one of the most significant deviations from the normal tooth morphology affecting the molars in both primary and permanent dentition. Taurodontism refers to the Enlargement of the pulp chamber, resulting in its bifurcation pushed toward the apex of a tooth’s root. This study evaluated the prevalence of Taurodontism from radiographs taken at the University of Ghana Dental School Oral Radiology Unit from January 2017 to December 2022. Methodology: In this cross-sectional study, panoramic and periapical radiographs of 1000 randomly selected patients who visited the Oral Radiology Unit from January 2017 to December 2022. Radiographs were evaluated for apically displaced pulp chamber. Data was statistically evaluated, and the chi-square test was employed to assess the prevalence of taurodontism in the upper and lower jaws (p Results: Taurodontism was found in 171 radiographs giving it a prevalence of 17.1% of which 57% (98 radiographs) were from females and 43% (73 radiographs) were from males. This finding was not significant (p > 0.05). Taurodontism occurred more in the maxilla (289 teeth, 80.7%) compared to the mandible molars (186 teeth, 64.3%) giving it a ratio of 1.6:1. This finding was highly significant (p Conclusion: Taurodontism is relatively common in the Ghanaian population affecting more females compared to males according to this study. Further studies using a large sample need to be carried out to determine its incidence in the general community.
文摘目的:观察下颌阻生第三磨牙(impacted mandibular third molars,IM3Ms)拔除术后的自然转归及对邻近下颌第二磨牙(mandibular second molars,M2Ms)的影响。方法:选择下颌第三磨牙骨埋伏阻生的患者34例(51颗IM3Ms),使用超声骨刀、气动涡轮手机拔除患牙,分别于术前、术后1周及术后6个月随访,观察术后反应及M2Ms远中骨缺损情况。比较手术前后M2Ms远中骨缺损深度,并分析其影响因素。采用SPSS 29.0软件包对数据进行统计学分析。结果:术前M2Ms远中骨高度未见明显缺损,但拔除IM3Ms时,由于去骨拔牙等操作产生骨缺损。术后6个月,骨高度虽有所恢复,骨缺损率减少,但未达到术前水平。IM3Ms埋伏阻生深度是恢复率的主要影响因素。探诊深度较术前显著增加。术后24 h内患者疼痛感较重,术后1周缓解,但仍存在轻度开口受限及面部肿胀。拔除IM3Ms对患者日常生活、情绪、工作、睡眠影响较小。结论:下颌第三磨牙拔除术后,邻近第二磨牙远中骨高度部分恢复,但未达到术前水平。拔牙手术中需采取更加精细的手术技巧,以减少对邻近牙和骨组织的影响。同时,拔除IM3Ms后应给予镇痛药物,加强卫生宣教,提高患者术后舒适度。
文摘目的 利用锥形束CT(cone beam computed technology,CBCT)分析下颌阻生第三磨牙(mandibular third molar,MTM)对第二磨牙(mandibular second molar,MSM)不同部位牙槽骨的影响,为临床MTM的拔除指征及MSM的诊断、治疗及预后提供理论依据。方法 收集山西省人民医院口腔中心CBCT数据库中随机抽取18岁以上500例阻生MTM的CBCT图像,根据阻生深度及阻生角度分别确定PG及Winter分类,测量MTM与MSM釉牙骨质界之间(CEJ)的距离及第二磨牙颊侧、舌侧、近中、远中牙槽骨吸收的距离。采用Friedman秩和检验比较颊、舌、近中、远中牙槽骨吸收;采用非参数Kruskal Wallis检验、Mann-Whitney U检验分析不同阻生类型间牙槽骨吸收的差异;采用Spearman秩相关及多元线性回归分析各因素与牙槽骨吸收最大侧的关系。结果 远中牙槽骨吸收距离(distal alveolar bone loss of mandibular second molar,MSM-DBL)高于颊侧、舌侧及近中。在Winter分类中,牙槽骨吸收距离水平组最大,近中组次之,垂直组和远中组最小;在PG分类中,从低位、中位到高位牙槽骨吸收距离逐渐降低(P<0.001)。CEJ距离、阻生角度(11°~100°)以及阻生深度均为MSM-DBL的独立危险因素,前二者与MSM-DBL呈正相关(P<0.05)。本研究人群中,MSM-DBL男性高于女性(P<0.05),年龄与MSM-DBL不存在相关性(P>0.05)。结论 阻生MTM对MSM-DBL影响最大;CEJ距离、阻生角度、阻生深度、性别为MSM-DBL的影响因素。
