切牙髓腔近远中径的测定

本研究对８０例１５～８０岁正常人作切牙组ｘ线摄片。经定点测量后，统计显示，颈部髓腔宽１７ｍｍ，根中１／２处髓腔宽１．０ｍｍ，距根尖０．５ｍｍ处髓腔宽０．１７ｍｍ。颈部髓腔宽１．４ｍｍ，根中１／２处髓腔宽０．８ｍｍ，距根尖０．５ｍｍ处髓腔宽０．１１ｍｍ。颈部髓腔宽０．７ｍｍ，根中１／２处髓腔宽０．４ｍｍ，距根尖０．５ｍｍ处髓腔宽０．０９ｍｍ。颈部髓腔宽０．９ｍｍ，根中１／２处髓腔宽０．４ｍｍ，距根尖０．５ｍｍ处髓腔宽０．０８ｍｍ。本文对其结果进行了应用性讨论。     

上颌第一前磨牙髓腔形态的影像学研究

目的:利用RVG(radio visio graphy)数字化X线成像系统测量上颌第一前磨牙髓腔解剖形态的相关数值,为临床诊断、治疗提供重要参考依据。方法:收集拔除的上颌第一前磨牙70颗,牙齿发育完全、根尖完整,用RVG数字成像系统分别拍摄近远中向数字X线片,在图像上测量髓腔形态的相关数值。结果:上颌第一前磨牙颈部髓室的颊腭向厚度(4.34±0.49)mm,颊尖至颊侧髓角之间的距离(5.84±0.58)mm,腭尖至腭侧髓角之间的距离(5.95±0.56)mm;牙尖至髓顶的距离(7.62±0.75)mm,牙尖至髓底的距离(10.38±1.44)mm;髓室高度(2.98±0.98)mm;髓顶至根分叉的距离(7.67±1.79)mm,髓底至根分叉的距离(4.59±1.48)mm。2根管口之间的距离(3.22±0.76)mm,2根管根中1/2之间的距离(3.71±1.43)mm,2根尖孔之间的距离(3.91±2.23)mm。结论:提供成人上颌第一前磨牙髓腔解剖的形态特征,为临床诊断和治疗时参考。     

外伤变色牙髓腔钙化的临床研究

目的：研究外伤变色牙髓腔钙化情况。方法：选择外伤变色牙，拍摄X线片，观察髓腔钙化情况，并作根管治疗术。结果：93例中有9例髓腔变窄，6例髓腔完全钙化，78例有根尖周稀疏区。结论：年轻恒牙髓腔钙化发生率高于成熟恒牙，并随时间推移髓腔钙化发生率增高，外伤变色牙大多有根尖周稀疏区。     

下颌恒切牙根管形态的影像学研究

目的：探讨下颌恒切牙根管解剖形态的影像学特征，为临床采用X线片评估该牙根管系统提供依据。方法：中国人下颌恒切牙300个，采用传统X线胶片和数字化X线片从唇舌向和近中远中向投照牙片，两名牙体牙髓专科医师同时观察牙片，判读根管数目、根管类型、根管钙化程度，并根据根管直径推测根管横切面形状。结果：下颌恒切牙有1个根管（67．89％）和2个根管（32．11％），唇舌向X线片双根管检出率（3．34％）明显低于近中远中向（32．11％）（P〈0．05）。根管类型按Vertucci分类，Ⅰ型67．9％，Ⅱ型11．4％，Ⅲ型18．1％，Ⅳ型0．7％，Ⅴ型1．0％，Ⅵ型1．0％。根管钙化率：1级为89．67％，2级为7．33％，3级为3．0％。根管横切面形状扁长形以根中1／3最高，达85．6％。结论：下颌恒切牙根管解剖形态复杂，临床上唇舌向X线片可能掩盖部分根管解剖信息。     

牙科三维CT研究上颌乳磨牙髓腔

目的：测量上颌乳磨牙髓腔形态参数，为乳磨牙牙体解剖学提供基础数据，并供临床应用参考。方法：用牙科三维CT对20个上颁乳磨牙进行扫描并测量髓室相关参数。结果：上颌第二乳磨牙髓室颊舌向最大距离、根分叉处水平面腭侧根管近中远中向最大距离、颊侧近中根管颊舌向最大距离，均比上颌第一乳磨牙大（P〈0．05），而髓室高度较第一乳磨牙小（P〈0．05）。髓室近中远中向最大距离、髓室底最高点水平面到根分叉处垂直距离、根分叉处水平面根管其他测量值二者无显著性差异（P〉0．05）。左右分组比较无显著性差异（P〉0.05）。结论：牙科三维CT是一种精确测量牙体解剖形态的有效方法，熟悉乳磨牙髓腔解剖对于成功地进行牙髓、根尖周病治疗非常重要。     

前牙髓腔完全钙化的临床研究

目的：探讨完全钙化根管行根管治疗术的可行性。方法：对26例完全钙化前牙根管行根管治疗术，进行术前术后X线片对比研究。结果：24例顺利完成根管治疗术，2例因根管口完全钙化行根尖手术。结论：完全钙化的前牙根管X线片上显示为根管闭锁，临床上可通过寻找根管口，逐步扩大根管完成根管治疗术，以避免根尖手术或牙拔除术。     

再论磨牙髓腔解剖研究及临床意义

目的：恒磨牙髓腔解剖的再研究。方法：通过开髓、根管预备，测量扩大针进入根管角度和根管长度，冠颈横断观察。结果：髓室底形态有４型；根管口分布类型：上颌磨牙有２类５型，下颌磨牙有３类４型；扩大针进入根管角度及根管长度因根而异。结论：成功地进行牙髓、尖周病的治疗，熟悉髓腔解剖十分重要。     

恒牙初期前牙开畸形形态特征的初步研究

借助Ｘ线头影测量手段，分析了１８例恒牙初期前牙开患者的形态特征。结果表明，恒牙初期前牙开患者的前下面高、矢状角、矢状比与正常相比均显著性增加，上、下颌的后边长与正常相比均显著性减小，但上、下颌基骨的长度未见显著性差异。     

儿童恒前牙切髓术后根髓组织学研究

目的：牙本质桥的形成是牙髓修复的特征，但至今人们对牙本质桥下方的牙髓组织是否健康仍有争议。本研究目的是观察儿童外伤冠折恒切牙切髓极后根髓的组织学特征，以证实牙髓修复后的牙髓组织变化状况。方法：对16例8－9岁儿童外伤冠折露髓的恒前牙行切髓术，氢氧化钙制剂覆盖牙髓断面，并在牙本质桥形成及根尖发育完成后不同时期行去髓术，将去除的根髓组织固定，常规组织学切片，显微镜观察。结果：术后12－24个月根尖发育完成，此时组织学观察可见牙本质桥下方的根髓组织无明显炎症。至36－48个月，牙髓组织逐渐出现退行性变，例如纤维性变和牙髓钙化等。结论：切髓术后2年内牙本质桥下方的根髓是正常的，而后牙髓逐渐出现退行性变，切髓术可作为儿童前牙冠折露髓的一种暂时治疗方法，当牙根发育完成时，则应采用去髓术。     

Autoradiographic investigation of proliferative responses in rat incisor pulp after vincristine administration

0.7 mg/kg VCR was given to nine rats in three experimental groups. Twenty-three hours after VCR injection the animals were injected with ³H-thymidine. The animals were sacrificed 24, 48 and 72 h after the VCR injection, and by comparison with nine control animals similarly injected with sodium chloride solution and nucleotide, it was shown that VCR causes a delayed migration of pulp cells from the proliferative pool and a small but distinct inhibition of the incisal growth of the incisors. The growth inhibition corresponded to the normal growth over a 24-h period in nou-VCR-injected animals.     

Coronal pulp size in molars: a study of bitewing radiographs

AIM: To: (i) study coronal pulp dimensions in human first molar teeth; (ii) investigate the effects of restorations on pulp size; (iii) determine differences in dimensions between teeth of Mongoloid patients and teeth of other ethnic groups; and (iv) record the presence of pulp stones. METHODOLOGY: Bitewing radiographs of 121 subjects (mean age, 20.9 years) were taken under standardized conditions. The films were digitally scanned and nine measurements were made from the image of each first molar. The data were analysed in terms of presence or absence of restorations and in terms of racial group. Differences were examined using Student's t-test, Pearson correlations and Levene's test. RESULTS: A total of 445 teeth were analysed. Large crowns were correlated to large pulps. Teeth restored with occlusal and proximal restorations had significantly smaller pulps (P = 0.044 and 0.004, respectively), but no difference was found in pulp area in the clinical crown between the restoration types. Mongoloid crowns were shorter and more bulbous. Pulp areas of maxillary molars and pulp widths at the cervix of mandibular molars were significantly larger in Mongoloids. The pulp area in the clinical crown correlated to pulp horn height for Mongoloids and others and for maxillary and mandibular teeth. No differences were found between the heights of pulp horns in the Mongoloid and other teeth. Four of the pulp measurements demonstrated sexual dimorphism. Stones were present in almost 10% of the subjects, representing 4% of the tooth pulps examined. CONCLUSION: Even teeth with shallow occlusal restorations had reduced pulp spaces. There were significant differences in pulp and crown dimensions between the teeth of Mongoloid patients and those of other patients.     

Glycosaminoglycan turnover and synthesis in the rat incisor pulp

abstract – The rate of in vivo turnover and in vitro synthesis of the glycosaminoglycans (GAGs; acid mucopolysaccharides) of the dental pulp loose connective tissue from rat maxillary incisors has been investigated by isotope methods. The biologic half-life of ³⁵SO₄ in whole tissue digests was found to be 4.5 d. Of the sulfated GAGs the chondroitin-4-sulfate fraction was shown to have a more rapid turnover in vivo than the chondroitin-6-sulfate fraction, 4.1 and 5.2 d, respectively. The fraction containing keratan sulfate and glycoproteins had a biologic half-life of 6.8 d. Slices of rat incisor pulps were incubated in vitro with ³⁵SO₄ and the rate of incorporation into the different GAG fractions was determined. After a lag-phase of 15 min, this rate was linear with time. The chondroitin-6-sulfate fraction showed a more rapid uptake than the chondroitin-4-sulfate fraction, and the uptake by keratan sulfate + glycoprotein fraction was much lower. A similar in vitro experiment using [¹⁴C] acetate was performed. Contrary to the sulfate incorporation there was an extended lag-phase, and the total incorporation was much lower.     

Maxillary permanent central incisor with abnormal crown size and dens invaginatus: case report

Abstract An otherwise healthy young Caucasian Australian was referred because of the unusual radiographic appearance of a maxillary permanent incisor. The tooth was found to have an enlarged crown with palatal cusp and dens invaginatus. Over five years' follow-up the tooth showed no signs of pulp necrosis. The major problem was the correction of the patient's esthetics as he approached adulthood.     

Ontogeny of class II antigen expressing cells in rat incisor pulp

Abstract— Class II antigen expressing cells are generally associated with the early phase of the immune response. Dendritic cells and macrophages expressing these cell surface antigens have recently been demonstrated and characterized in the dental pulp. The present study was undertaken to determine when the pulp receives its immunologic defense potential by examining the temporal appearance of class II antigen expressing cells in the rat incisor pulp. Pulp tissue specimens obtained at various time periods from a gestational age of 16 days to 14 wk after birth were examined by immunohistochemistry using O x 6 as a primary antibody and the ABC-technique. Comparisons were made with tissue samples from the spleen, intestine, skin and oral mucosa. At birth, all tissues, except for the pulp, presented cells expressing class II antigen with a dendritic appearance in a number and orientation resembling the mature tissue. A complete distribution of these cells was not seen in the dental pulp until 7 weeks following birth. Data show that the dental pulp acquires its ultimate structural arrangement of immune cells later than other tissues.     

改良失活法在牙髓炎疼痛控制中的临床效果

目的:比较改进多聚甲醛牙髓失活法与传统失活法的临床效果,并观察其在60岁以上老年人的效果差异.方法:观察两种方法在A、B两个年龄组间牙髓失活时疼痛发生率、牙龈坏死、所封失活剂能否被完整取出、牙髓失活效果以及去除冠髓时牙髓出血情况,并作统计学分析.结果:两个年龄组改良方法疼痛发生率均低于传统方法(P＜0.01).A组改良法失活效果优于传统法(P＜0.01);B组改良法与传统法差异无显著性(P＞0.05).改良法失活剂完整取出率高于传统法(P＜0.01);两个年龄组间差异均无显著性(P＞0.05).各组均没有牙龈坏死情况.结论:改良法优于传统法.可以有效提高牙髓失活效果,降低疼痛等并发症的发生,缩短患牙的疗程.     

高频电流处理家兔牙髓的初步实验研究

目的 验证高频电流处理家兔牙髓的效果。方法 选取约3月龄的健康实验家兔55只,共220颗切牙,分成8个实验组和2个对照组。实验组暴露牙髓后分别采用5、10、15、20W输出功率下的高频电流处理家兔牙髓,对照组牙髓不作任何处理。实验完成后,即刻将两组家兔切牙连同牙槽骨一同切下,制成联合切片,通过组织学方法 将实验组和对照组的切片进行对比,观察实验组处理后的牙髓组织、根管壁及根尖周组织的变化,比较各实验组中各组织损伤的程度。结果 5、10W组高频电流处理后的牙髓,主要是出现局部点灶状的变性坏死区,变性坏死区的改变以凝固性坏死改变为主。15、20W实验组高频电流可令根髓出现变性坏死及断裂现象,可达到药物失活牙髓的组织学变化指标。各实验组根管壁均无异常变化,根尖周未发现副损伤。结论 采用20W输出功率下的高频电流处理兔牙髓,可使牙髓失活,且未发现根管壁和根尖周的副损伤。?     

Activation of sympathetic fibres in the pulp by electrical stimulation of rat incisor teeth

Previous of the sympathetic nerve supply of the rat mandibular incisor pulp have shown conflicting results. Here, the neurovascular control of the rat lower incisor pulp was investigated by stimulating the tooth crown and the cervical sympathetic trunk electrically and monitoring blood-flow changes in the pulp by laser Doppler flowmetry. In addition the presence of noradrenaline (NA) in the pulp and gingiva was examined biochemically in untreated and sympathectomized animals by high-performance liquid chromatography. The tissue concentrations of NA in the pulp were 11-fold greater than those of gingiva. Surgical sympathectomy significantly reduced the NA content in the pulp by 76%. Monopolar electrical stimulation of teeth (25–50 μA) for 1 min resulted in a frequency-dependent reduction followed by an increase in pulpal blood flow. At 16 Hz the reduction in blood flow was 65% and the subsequent increase was 9%. After intravenous administration of the -adrenoceptor antagonist phentolamine, the stimulation-induced reduction in pulpal blood flow was diminished by 94% while the increase was significantly enhanced (from 9 to 40%). Infusion of the β-adrenoceptor antagonists propranolol and timolol significantly reduced this increase in blood flow by 53 and 55%, respectively. Preganglionic sympathetic nerve stimulation also induced a frequency-dependent reduction followed by a slight increase in pulpal blood flow. This reduction in blood flow was almost abolished after -adrenergic blockade and there was no subsequent increase. These findings suggest that there are sympathetic nerve fibres in rat incisor pulp and that they are activated upon monopolar electrical stimulation of teeth resulting in -and β-adrenoceptor mediated blood-flow responses.     

磨牙髓腔解剖研究及其临床意义

对４００个磨牙开髓部位、髓室底形态、根管口分布、根管数目、牙齿长度等进行初步研究，特别对上颌磨牙近中颊根形状与极管数目的关系作了分析，将髓室底形态归纳为４种类型；上颌磨牙分为３类６型、下颌磨牙分为３类４型，上颌磨牙近中颊根双根管的发生率第一磨牙为４０％，第二磨牙为２３％。     

Endodontic treatment of an invaginated maxillary lateral incisor with a periradicular lesion and a healthy pulp

AIM: To report the healing of a periradicular lesion following nonsurgical root canal treatment of a dental invagination. SUMMARY: A case of dens invaginatus type 3 with a periradicular lesion and a healthy pulp is reported. Nonsurgical root canal treatment of the invagination was performed successfully and resolved an associated periradicular lesion. Despite the complex anatomy and a diagnosis of apical periodontitis, pulp health was retained after endodontic treatment of the invaginated canal. Clinical considerations and treatment are discussed and reported. KEY LEARNING POINTS: Dens invaginatus can present in a variety of forms, knowledge of which can usefully inform endodontic diagnosis and treatment. In certain cases, success can be achieved by treating the invagination alone. Pulp health may be preserved during and after treatment of an infected invagination.