替牙期骨性Ⅲ类患者上前牙牙槽骨形态及其影响因素

目的 评估替牙期骨性Ⅲ类患者上前牙区牙槽骨形态，并探讨其影响因素。方法 选取替牙期骨性Ⅲ类患者48例，基于治疗前的锥体束CT(CBCT)，测量上颌中切牙和侧切牙唇舌侧的牙槽骨厚度和高度，测量牙齿长度、前牙倾斜度、下颌平面角。结果 上颌中切牙舌侧牙槽骨厚度为(3.34±1.33)mm，上颌中切牙唇侧牙槽骨厚度为(1.24±0.51)mm，上颌中切牙舌侧牙槽嵴顶距釉牙骨质距离(1.30±0.89)mm，上颌侧切牙唇侧牙槽嵴顶距釉牙骨质距离(1.68±0.88)mm。上中切牙舌侧牙槽骨厚度、唇侧牙槽骨高度与切牙唇倾度负相关，上切牙唇侧牙槽骨厚度与牙齿长度和下颌平面角负相关。结论 替牙期骨性Ⅲ类患者上切牙唇侧牙槽骨较薄，附着高度较低，舌侧牙槽骨较厚、附着高度较高。上切牙牙槽骨形态与切牙唇倾度、牙齿长度、下颌平面角均有相关性。     

胶原膜引导牙周组织再生的研究 Ⅲ．牙周硬组织新生及钙化过程动态观察

对胶原膜引导牙周组织再生术后标本，采用四环素荧光标记法，观察探讨了引导牙周组织再生术后牙槽骨及牙骨质形成过程中的钙化过程。结果为牙骨质的新生和钙化早于牙槽骨，牙骨质在新生钙化过程中逐渐增厚，由根方向冠方伸展。牙槽骨形成及成熟与原骨界线不清，有哈佛氏管形成。     

胶原膜引导牙周组织再生的研究 Ⅲ.牙周硬组织新生…

对胶原膜引导牙周组织再生术后标本，采用四环素荧光标记法，观察探讨了引导牙周组织再生术后牙槽骨及牙骨质形成过程中的钙化过程。结果为牙骨质的新生和钙化早于牙槽骨，牙骨质在新生钙化过程中逐渐增厚，由根方向冠方伸展。牙槽骨形成及成熟与原骨界线不清，有哈佛氏管形成。     

人牙骨质、牙周膜、牙槽骨中Ⅰ、Ⅲ、Ⅳ型胶原的检测

本研究目的为检测人牙骨质、牙周膜和牙槽骨组织中Ⅰ、Ⅲ、Ⅳ型胶原的分布和含量。应用免疫组化和图像分析法测得：Ⅰ型胶原占牙周膜的７８．０６％、牙骨质的７３．０９％和牙槽骨的３０．５０％；Ⅲ型胶原占牙周膜的１１．７３％，在根尖部牙骨质和相对应的牙槽窝骨组织也观察到Ⅲ型胶原；Ⅳ型胶原仅见于血管基膜；夏柏纤维为Ⅰ型着色，但周边显示有Ⅰ型胶原和Ⅲ型胶原的“鞘”状着色。结果显示了人正常牙周组织的胶原状况，将有助于进一步对牙周组织病理过程和再生效应的研究。     

关于牙齿近中移动的实验研究

目的　通过动物实验对牙齿近中移动的发生机制进行探讨。方法　以五指山系小型猪上下颌第一磨牙为实验对象 ,通过模型测量分析实验牙近中移动情况 ,以二甲酚橙和盐酸四环素作荧光标记进行组织学观察。结果　下颌有、无对实验牙 ,16周移动量分别为 0 14mm和 1 2 1mm ,上颌实验牙 2 4周移动量分别为 1 36mm和 2 0 8mm。实验牙远中牙槽骨可见荧光标记 ;无对实验牙在垂直方向上有牙槽骨改建发生 ;下颌无对实验牙较有对实验牙远中牙槽骨荧光带间距离大 ;近远中牙骨质都有荧光带形成。结论　实验结果不支持越隔纤维作用或磨牙萌出力作用引起牙齿近中移动的观点 ;牙齿近中移动与颌骨内应力分布有关 ,牙槽骨改建的量与牙齿近中移动量呈正相关     

提高牙及牙周组织联合石蜡切片质量的探讨

在口腔组织病理学、牙体牙髓病学、牙周病学、修复学、口腔材料学、药物学等很多科研领域，都需要制作牙及牙周组织联合切片进行观察和研究。由于牙体组织中的牙釉质、牙本质、牙骨质和牙槽骨中含钙较多，坚硬且致密。为难切、硬脆、易碎组织；而牙髓、牙龈、牙周膜为软组织，制作过程中易受挤压、牵拉变形分离，甚至脱落。故用常规石蜡切片方法很难制出优良的牙及牙周组织联合切片。     

灭滴灵复合药物空管疗法的实验研究及五年临床疗效观察

用灭滴灵复合药物对２４个狗单根牙实验性尖周炎进行空管药物疗法，并用另外２４个狗单根牙实验性尖周炎为两治疗对照组。对这４８个实验狗牙在实验后４５ｄ，９０ｄ和１８０ｄ对其尖周的组织学变化进行了显微镜观察。狗牙尖周炎细胞减少或消失，有明显胶元纤维修复，牙骨质和牙槽骨右明显新生组织沉积线，时间越长，效果越好。文中还对１６１人１８３个矛用灭滴灵复合药物空管疗法治疗的各类患牙经５年随访观察。获９１．８％的治愈率。     

离体牙牙冠表面各部位电阻的测量

目的：研究牙冠表面电阻状态。方法：选用了４５个新鲜离体牙，测量其牙冠表面各点与牙髓间的电阻。结果：在牙尖部位的电阻值最高，且与其他部位相差显著；颈部釉质处电阻值次之，并与合面窝沟、牙颈部釉牙骨质界处的电阻值相差显著；合面窝沟、牙颈部釉牙骨质界处的电阻值较低。结论：牙体表面各部位的电阻值有很大的差异。     

牵张新生牙槽骨中牙移动的实验研究

运用牵张成骨增加颌骨骨量,再将牙移入新生牙槽骨中,成为正畸科医师不拔牙矫治牙量—骨量不调患者的新方法。本研究通过实验犬下颌骨牵张后,新生牙槽骨中牙移动的放射影像学、组织学观察及模型分析,为探讨人类正畸牙移动的最佳时机提供依据。 材料和方法 选成年雄性猎犬2只,将4个口内型骨牵张器分别安装于下颌第一磨牙与第四前磨牙间,其(牙合)方部位以磨牙铸造冠及前磨牙区夹板为支持,根方用穿通螺钉固定于颌骨内。下颌第一磨牙与第四     

牙连牙周组织切片的特殊取材及双重脱钙技术

口腔组织病理学教学、病理诊断，尤其是很多口腔医学动物实验研究，都需要制作牙及牙周组织联合切片对其全貌进行观察和研究。由于牙及牙周组织结构复杂，牙釉质、牙本质、牙骨质和牙槽骨内含有大量无机钙盐，主要以磷酸钙和碳酸钙的羟基磷灰石结晶分布于以胶原纤维为主要成分的基质中。牙釉质的钙含量高达97％，是非常硬脆致密、难切易碎组织。而位于牙中央的牙髓及位于牙周围与牙槽骨之间的牙周膜为软组织，制片过程中易受挤压牵拉变形、分离甚至脱落流失。脱钙前一次性常规取材法不仅损伤牙龈、牙周膜和牙髓，而且很难将彼此间有密切解剖生理及病理关系的各种组织都呈现在同一平面上，切片时切不全、切不到或者切没了。     

乳牙牙槽骨丧失的危险因素分析

目的 研究儿童乳牙牙槽骨丧失的危险因素。方法 选择106名在北京大学口腔医院儿童口腔科就诊的3-10岁初诊儿童为研究对象,检查儿童的龋齿、充填体、食物嵌塞、牙髓根尖病变、牙石和牙周状况。并拍摄后牙翼片,应用计算机定点测量釉牙骨质界到牙槽嵴顶的距离。以釉质牙骨质界到牙槽嵴顶的距离大于2 mm,牙槽嵴顶骨硬板不清晰、消失为牙槽骨丧失。根据牙槽骨是否丧失分为正常组和牙槽骨丧失组。采用SPSS 10.0软件分析两组龋均（dmft）和邻面dmft有无差异,并用Logistic回归分析牙槽骨丧失的相关危险因素。结果 106名儿童中,骨丧失组31名,占整个儿童的29％。骨丧失多发生在第一乳磨牙和第二乳磨牙之间。方差分析发现骨丧失组dmft和邻面dmft均高于正常组（P<0.01）。Logistic回归分析发现,牙槽骨丧失与邻面龋、不良充填体和根尖病变相关。结
论 儿童应积极完善治疗邻面龋,抑制根尖病变的进展,从而预防牙槽骨的丧失。     

Histopathologic changes in the pulpal and periapical tissues after surgical removal of the coronal pulp chamber of rat lower molar

With the specific aim of the examination of tissue-damage and repair of surgically exposed pulp and periapical region in rat molar model, 14 female Sprague-Dawley rats were used. The coronal portion of lower first molars was surgically removed and the teeth remained untreated for 3 weeks prior to euthanasia of the animals. During this experimental period, all animals were injected with fluorochrome agents twice at the 12th and 19th days, in order to monitor formation of hard tissues in the exposed pulpal chamber and on the surfaces of cementum and alveolar bone. For histologic examination using microradiography and fluorescent and light microscopy, resin-embedded ground sections and serial decalcified sections were prepared. Observations revealed that: (1) over half of the surgically treated teeth gave rise to the formation of osteodentin so that the exposed pulp was partially covered; (2) the number of root canals filled with necrotic tissues was less than 25% of the total teeth examined, while the majority comprised vital granulation tissues and newly formed osteodentin, in certain cases with the appearance of odontoblastic cells aligning on the dentin wall; and (3) active deposition of cementum on the root apex and remodeling of alveolar bone were prominent in most of the treated teeth. The overall results support the contention that rat molar pulp has high potential activities for tissue-repair including hard tissue formation after pulpal exposure to the oral enviroment.     

乳磨牙龋源性牙髓炎的根分叉异常表现(附24例术后分析)

目的：观察龋源性乳磨牙牙髓炎的根分叉异常表现及其活髓切断术后疗效分析。方法：对临床诊断为慢性牙髓炎、慢性牙髓炎急性发作的２４例２９个下颌乳磨牙行活髓切断术，摄取术前Ｘ线片，冠髓组织进行病理学检查。半年、１年定期复查。结果：牙髓组织炎症的患牙绝大多数Ｘ线片均显示其根分叉处骨组织的异常表现。术后１年除３例外，Ｘ线片显示根分叉处异常现象消失。半年、１年后疗效明显。结论：乳磨牙牙髓炎症常常伴发根分叉下方的根周组织感染。乳磨牙活髓切断术后需定期拍摄Ｘ线片复查。     

Periodontal regeneration of transplanted rat molars after cryopreservation

The effects of cryopreservation on periodontal regeneration of transplanted rat molars were investigated histologically and histochemically in rats. Bilateral first and second maxillary molars of 4-week-old Wistar rats were gently extracted and transplanted into the abdominal subcutaneous connective tissue immediately or after cryopreservation in liquid nitrogen overnight. Donor teeth were slowly frozen by a rate-controlling freezer (program freezer) using 5% dimethylsulfoxide (DMSO) and 6% hydroxyethyl starch (HES) as cryoprotectants. One-four weeks after transplantation, they were carefully excised with the surrounding tissues. Regeneration of acellular cementum, periodontal ligament, and alveolar bone were observed 2 weeks after immediate transplantation. The pulp was repaired by the ingrowth of granulation tissue from the root apex followed by the formation of calcified tissue. The regenerated periodontal ligament was positive for alkaline phosphatase (ALP). Small or mononuclear tartrate resistant acid phosphatase (TRAP) positive cells were scattered on the newly formed alveolar bone and on the hard tissue in the pulp, but there was no external or internal progressive root resorption at 4 weeks. Cryopreserved teeth had acellular cementum with a rough surface at 1 week, but with the increase of cementoblasts and the appearance of periodontal ligament and alveolar bone, the surface became smooth at 3 weeks. Epithelial rests of Malassez (ERM) also revived. After regeneration of the periodontal tissues at 4 weeks, there was no evidence of root resorption. Although the process proceeded slowly, the cryopreserved teeth showed the periodontal regeneration substantially similar to that of the immediately transplanted teeth without progressive root resorption, indicating that they could be applicable for clinical use.     

Autologous tooth transplantation to replace molars lost in patients with juvenile periodontitis

A method is described to replace perodontally destroyed first molars in patients with juvenile periodontitis by auto-transplantation of third molars. Fifteen molars which had been extracted due to periodontal destruction were replaced by autologous third molars with incomplete root formation. The patients were then observed for a period up to 7 years. In all cases complete regeneration of the alveolar bone took place and radiographically a normal periodontal membrane was extablished. All of the transplanted teeth continued their root formation and there was no radiographic evidence for root resorption, ankylosis or necrosis of the pulp. None of the transplanted teeth displayed pocket depths over 3 mm and no abnormal mobility was detectable.     

Alveolar bone changes after molar protraction in young adults with missing mandibular second premolars or first molars

ObjectivesTo assess the changes in alveolar bone of the mandibular second molars following molar protraction and investigate the factors associated with the alveolar bone changes.Materials and MethodsCone-beam computed tomography of 29 patients (mean age 22.0 ± 4.2 years) who had missing mandibular premolars or first molars and underwent molar protraction were reviewed. Alveolar bone level was measured as the distance from the cementoenamel junction at six points, buccal, lingual, mesiobuccal (MB), mesiolingual (ML), distobuccal (DB), and distolingual (DL), of the second molars at pretreatment (T0) and after molar protraction (T1). Factors associated with alveolar bone changes at the distal and mesial of the second molars were assessed.ResultsMean alveolar bone changes ranged from −1.2 mm (bone apposition) to 0.8 mm (bone resorption). The presence of a third molar impaction at T0 (P < .001), third molar angulation at T0 (P < .001), and Nolla''s stage of third molar at T0 (P = .005) were significantly associated with alveolar bone level changes distal to the second molars. Treatment duration (P = .028) was significantly associated with alveolar bone level changes mesial to the second molar.ConclusionsPatients with impacted third molars, third molars at an earlier stage of development, and mesially angulated third molars at pretreatment may have less alveolar bone resorption distal to the second molars following protraction. Patients with increased treatment time may have reduced alveolar bone resorption mesial to the second molars.     

Studies on protracted tissue reactions and repair after circulatory and skeletal damage to the rat mandible

The effect of circulatory and skeletal damage to the distal part of the mandible was studied on young growing rats after interruption of the inferior alveolar artery. The central part of the mandible including the incisor was most vulnerable to circulatory trauma. Maximal damage was seen when the inferior alveolar artery was interrupted combined with bilateral reflection of the mandibular periosteum. The damage produced then was a necrosis of the incisor pulp, odontoblasts and enamel organ and extensive resorption of the centrally-located compact bone. When both sides of the mucoperiosteum remained intact, damage to the main vessels of the mandible did not produce total necrosis of the incisor pulp. Reparative events with production of a fibrous connective tissue of the pulp and osteodentin production were seen. After resorption of sequestered bone was finished, this was replaced by a cell-rich type of bone which also replaced the alveola of those animals which had had their incisors excised. Hypercementosis was seen in the molars after 1 year. No respiratory activity in the incisor pulps was seen after the circulatory damage.     

Ultrastructural and histochemical examination of alveolar bone at the pressure areas of rat molars submitted to continuous orthodontic force

It is usually believed that repair in alveolar bone during orthodontic movement occurs after decreasing of force. However, we have recently observed signs of repair in previously resorbed cementum from human teeth exposed to continuous forces. In order to test the hypothesis that bone resorption and deposition occur concomitantly at the pressure areas, a continuous 15 cN force was applied in a buccal direction to upper first molars from eight 2.5-month-old male Wistar rats for 3 d (n = 4) and 7 d (n = 4). As a control, two additional rats did not have their molars moved. Maxillae were fixed in 2% glutaraldehyde + 2.5% formaldehyde, under microwave irradiation, decalcified in ethylenediaminetetraacetic acid, and processed for transmission electron microscopy. Specimens from one rat from each group were processed for tartrate-resistant acid phosphatase (TRAP) histochemistry. At both the times studied, the alveolar bone surface at the pressure areas showed numerous TRAP-positive osteoclasts, which were apposed to resorption lacunae. In addition, osteoblasts with numerous synthesis organelles were present in the neighboring areas overlying an organic matrix. Thus, this study provides evidence that the application of continuous forces produces concomitant bone resorption and formation at the pressure areas in rat molars.     

Autotransplantation of immature third molars into edentulous and atrophied jaw sections

The aim of the present study was to assess the results after transplantation of 85 immature third molars. Recipient site conditions varied and different surgical techniques were used. The long-term results after preparation of a new alveolus, splitting osteotomy of the alveolar process or use of free bone autografts were compared with the results after transplantation into a fresh extraction site (control group). Transplantations into prepared sockets showed equal results to the control group (94% respectively). Transplantations in connection with free bone autografts (84%) or after splitting osteotomy of the alveolar process (63%) showed poorer success rates, the differences between the latter and the control group being statistically significant. A possible correlation to revascularization disturbances of the pulp due to an insufficiency of the recipient site or to postoperative infection is suspected. The results show that transplantation of immature third molars is a safe, useful procedure when appropriate conditions of the recipient site are present. Where the alveolus is atrophic, a splitting osteotomy should be performed only in exceptional cases and preference should be given to alternative methods such as primary bone augmentation or bone-regenerative procedures.     

Delayed eruption of premolars with periodontitis of primary predecessors and a cystic lesion: a case report

Apical periodontitis after pulp therapy in a primary tooth can cause delayed eruption of the permanent successor. A case of bilateral delayed eruption of mandibular premolars is presented. The patient. a 13-year-old girl, was referred by her dentist. Oral findings showed that the right first and left second primary molars were retained. Other premolars had erupted. An orthopantomogram revealed apical periodontitis, affecting both retained primary molars. The right first mandibular premolar was impacted against the alveolar bone and root of the second premolar, and there was a large cystic lesion in close association with the left second mandibular premolar. Both primary molars were extracted, and the cystic lesion was treated by marsupialization. Fenestration and traction were performed on the right first premolar. Correct tooth alignment was achieved with orthodontic appliances. If the problem had been detected earlier, treatment of the premolars might have been easier. Clinical and radiological follow-up, therefore, of primary teeth that have undergone pulp therapy procedures should be performed until eruption of succedaneous teeth.