全颌曲面体层片和根尖片测量线距准确性的对比研究

目的：探讨全颌曲面体层片和根尖片在测量颌骨牙根区域线距时准确性的差异。方法：选取20例12～16岁的恒牙列正畸患者的记存模,在模型中嵌入5.00 mm钢珠作为标准参照物,分别拍摄全颌曲面体层片和根尖片,测量磨牙区、前磨牙区、尖牙区和切牙区影像中钢珠的水平径和垂直径,比较两种拍摄方法的测量值在各区域的变化,并与钢珠的真实值进行比较。结果：全颌曲面体层片测量值的失真率在后牙区较小,前牙区较大;根尖片的所有测量值中,失真率除少数前牙区较大外,其余区域的测量值接近;全颌曲面断层片水平测量值失真率较垂直测量值失真率大,根尖片则两者相近;全颌曲面断层片测量值较根尖片更接近实际值,但影像的放大率变化较大,而根尖片影像的放大率较大,但其失真率更恒定。结论：如使用标准参照物校正测量值,根尖片对颌骨内牙根区域线距的测量结果更可靠。     

数字化曲面体层摄影种植床失真率的定量研究

目的 研究下颌骨种植床数字化曲面体层摄影的水平、垂直失真率.方法 收集大小基本一致的40具成人头颅骨标本,在下颌种植床牙槽窝内放置放射模板,使用ORTHOPANTOMOGRAPH OP100 X线机进行数字化曲面体层摄影.在计算机上对放射模板进行测量.结果 数字化曲面体层摄影的平均垂直失真率前牙区4.03%、前磨牙区6.06%、磨牙区4.62%;水平失真率前牙区15.76%、前磨牙区15.03%、磨牙区7.00%,水平失真率均大于垂直失真率,且水平失真率变化大,而垂直失真率较为恒定.结论 数字化曲面体层摄影中下颌骨各区域垂直失真率明显低于传统曲面体层片,可为种植修复提供更准确的依据.     

曲面断层片在不同种植床失真率的初步研究

目的：探讨颌骨不同种植部位在曲面断层片上的失真率。方法：对132颗种植床进行颌骨曲面断层摄影,利用直径5.0mm的钢珠在不同种植床的影像进行直接测量,前牙区37颗,前磨牙区23颗,磨牙区72颗,计算钢珠失真率。结果：在曲面断层片上前牙区失真率为28.16%,前磨牙区失真率为27.94%,磨牙区失真率为28.22%。颌骨曲面断层片的平均失真率为28.17%。结论：颌骨曲面断层片上不同部位失真率不同,为种植术前制定治疗计划提供依据。     

不同测量方法对种植术区垂直骨量的临床评价

目的：应用不同方法对种植标记物垂直向失真率的测量,对拟种植区域骨量进行正确评价。方法：在普通X线胶片上应用直接测量和间接数字化图像的计算机辅助测量法对已知长度的种植体进行测量,并与在直接数字化全景片（DR）上标记物测量的结果进行失真率对比,了解3种测量方法之间失真率的差异。结果：普通胶片应用直接测量法得到不同区域垂直向失真率大于间接数字化图像的计算机辅助测量结果,而在DR上测量得出的误差率明显小于前者。结论：应用全景片进行种植术前检查及骨量评估中,DR测量结果较普通胶片直接测量和间接数字化图像的计算机辅助测量计算出的失真率更小,数据更接近真实值,可为临床种植术前及术后评估提供可靠依据．     

不同牙位即刻种植临床效果探讨

目的 探讨前牙区、双尖牙区、磨牙区即刻种植的临床效果。方法 选择2007年1月至2012年1月在湛江市第一中医院口腔科就诊的种植病例36例,微创拔除患牙后即刻植入CDIC种植体39枚,其中上颌前牙区18枚,下颌前牙区7枚,上颌双尖牙区11枚,下颌第一磨牙区3枚。除磨牙区延期修复外,其他牙位均在48 h内做临时冠修复。3～6个月后完成烤瓷冠永久修复。所有患者修复后追踪随访1～6年。结果 上颌前牙区、下颌前牙区、上颌双尖牙区种植体均有良好的骨结合,观察期内成功率均为100%;下颌第一磨牙区有1枚于18个月后发生松动而脱落,观察期内成功率为66.6%。结论 在适当选择病例的情况下,即刻种植可成功应用于临床,且在前牙区、双尖牙区成功率较高,磨牙区成功率略低。     

骨性安氏Ⅲ类错的矫治体会

目的 :矫治骨性安氏Ⅲ类错。方法 :拔除下颌第一恒磨牙 ,拉下双尖牙向远中 ,下第二恒磨牙向近中 ,关闭拔牙隙后 ,后牙为牙尖交错 ,同时解除后磨牙区拥挤 ,加舌栅使舌后退带动下颌后退以矫治前牙反覆盖和矫治不良舌习惯。矫治完成后下颌为固定保持 ,上颌为活动保持同时加舌栅。结果 :从X线头影测量值及面像看下颌骨长度得到较好抑制 ,但面下 1/ 3高度抑制较差 ,口内像见后牙关系改善好 ,前牙反覆盖解除 ,前牙无明显唇舌倾。结论 :拔下颌后磨牙矫治骨性安氏Ⅲ类可较好的抑制下颌骨长度发育 ,但应尽量在早期面下 1/ 3高度未过长时即开始矫治。     

口腔种植学

牙种植即刻修复的临床应用研究；影响种植牙成功率的临床操作因素分析附830枚种植体植入修复报道；种植固定义齿修复下颌磨牙游离端缺失的临床观察；牙种植数字化全景X线片失真率的临床评价；联合支持早期种植修复前牙缺失临床观察；Bio-Gide膜与钛膜在牙种植术中的临床应用研究；犬颧骨牵张成骨后种植体植入时机的实验研究。[编者按]     

根分叉病变的解剖学基础

根分叉形态通常出现在上颌磨牙、下颌磨牙和上颌双尖牙中，也可能出现在多根的前牙、尖牙和下颌前磨牙中。有时两个融合牙之间的融合部分也可能形成一个类似根分叉的形态。根分叉区域的解剖特点比较复杂，由此决定了根分叉病变在治疗上的复杂性。了解根分叉区域的解剖特点，对于临床和科研工作都具有重要的指导作用。     

新型压低下颌磨牙矫治器的临床应用

目的 评估新型压低下颌磨牙矫治器压低下颌磨牙的疗效及应用价值.方法 选择7例需要压低下颌磨牙治疗的前牙开患者,治疗前、后通过临床检查、牙颌模型分析及采用Winceph7.0数字化X线片分析软件测量头颅侧位片,评价临床压入效果,使用SPSS 17.0统计软件包对数据进行分析.结果 7例患者经过平均4个月的治疗,均取得比较明显的治疗效果.治疗前、后头影测量分析表明:下颌第一磨牙的平均压入量为(1.92±0.44)mm,矫治前、后相对于基准平面(MP平面)的垂直距离差异有统计学意义(P<0.05).上颌第一磨牙平均压入量为(0.36±0.25)mm,矫治前、后相对于基准平面(PP平面)的垂直距离差异没有统计学意义(P>0.05).X片显示被压低的下颌磨牙未出现明显的牙根吸收.结论 新型下颌磨牙压低矫治器用于压入下颌磨牙治疗前牙开畸形效果明显,压入治疗未引起明显的牙周及牙根损害.     

前方牵引与推磨牙向后联合矫正骨性Ⅲ类错及上颌埋伏双尖牙

目的 :本文报道六例上颌发育不足者 ,并存在于上颌无自行萌出能力的第二双尖牙 ,安氏Ⅲ类患者 ,采用前方牵引矫正器与推上颌磨牙向后联合矫正治疗。方法 :六例安氏Ⅲ类患者均为 11 13岁 ,临床检查面部中三分之一凹陷 ,下颌不能退到对刃。第一恒磨牙均为近中 ,上颌第二双尖牙为双侧或单侧埋伏 ,上颌第一恒磨牙与上颌第一双尖牙之间无间隙 ,上颌第二双尖牙无自行萌出条件。矫正方法上颌前方牵引器与口内第一双尖牙的颊侧作牵引钩进行弹性牵引。约六个月上颌第一恒磨牙做带环 ,上颌第一恒磨牙与上领第一双尖牙之间置钛镍推簧 ,开展间隙。间隙充余后上颌第二双尖牙牵引导萌排入牙列。配合下颌矫正 ,Ⅲ类牵引 ,排除前牙反。结果 :经前方牵引与推磨牙向后联合矫正后 ,上颌硬组织改变明显 ,上颌向前发育 ,上牙弓长度增加 ,下颌后退 ,前牙覆覆盖情况正常。上颌埋伏第二双尖牙牵引导萌调整到位后 ,平均上颌牙弓长度增加 10 16毫米。无根或短根的埋伏阻生牙 ,矫正后根生长与同名牙根相同。矫正结果表明 ,无根或短根的埋伏阻生牙在生长发育期及时矫正 ,创造萌出条件 ,其牙根有再生长再发育的潜力。结论 :经前方牵引与推磨牙向后联合矫正后 ,既牵引上颌骨向前生长又为阻生牙生长开创了间隙 ,使阻生牙调整入列 ,     

Total impaction of deciduous maxillary molars: two case reports

AIM: The purpose of this report is to present two cases of totally impacted maxillary deciduous molars, considered a rarity in dental practice. BACKGROUND: Primary tooth impaction is quite rare during the development of primary dentition. Various factors contribute to the impaction of a deciduous tooth, including anklyosis, congenitally missing permanent teeth, defects in the periodontal membrane, trauma, injury of the periodontal ligament, precocious eruption of the first permanent molar, defective eruptive force, or a combination of these factors. REPORTS: Case #1: An 18-year-old male presented with a complaint of spontaneous repetitious pain in the maxillary right premolar region. The maxillary right second premolar was clinically absent. Panoramic and periapical radiographs revealed an impacted second premolar close to the inferior wall of the maxillary sinus and an impacted deciduous molar deeply embedded in bone within the maxillary sinus. Case #2: A 14-year-old girl presented with a complaint of crowding of the maxillary teeth. The maxillary right second premolar and the maxillary permanent canines were clinically absent. A panoramic radiograph revealed an impacted maxillary right second premolar and an impacted deciduous molar embedded within bone close to the inferior wall of the maxillary sinus. SUMMARY: The total impactation of deciduous teeth is a rare condition, and few cases have been reported in the literature. The condition generally affects the mandibular second deciduous molar and the maxillary first deciduous least often. In this paper, two cases of totally impacted maxillary deciduous molars are reported.     

The vertical dimension: the "low-angle" patient

The patient who has a diminished anterior facial height and excess posterior facial height must be treated with a "different" diagnosis and treatment plan. The mandibular incisors must be left in their pretreatment positions--or facial balance will be compromised. They must not be proclined to eliminate crowding or to level a curve of Spee. The three most common diagnostic "schemes" for these patients are: (1) third molar extraction; (2) maxillary first premolar and mandibular third molar extraction; and (3) maxillary first premolar and mandibular second premolar extraction. This article will attempt to explain why certain diagnostic decisions are made. Case reports are used to illustrate the three most common treatment plans.     

Lower premolar extraction/removable plastic Herbst treatment for mandibular retrognathia

The patient was a 12-year-old girl with a Class I malocclusion characterized by maxillary arch width constriction, dental crowding, and mandibular retrognathia. Treatment goals related to the chief compliant were anterior mandibular repositioning, maxillary arch expansion, and dental alignment. Because the preexisting overjet was minimal and prevented adequate anterior repositioning of the mandible, lower first premolar extraction was recommended to increase the overjet and allow greater anterior repositioning. Treatment was divided into four stages: (1) extraction of mandibular first premolar teeth, alignment, space closure, and an increase in the overjet, (2) anterior mandibular repositioning with a removable plastic Herbst appliance, (3) arch alignment and detailing of the occlusion with full fixed appliances and a tooth positioner, and (4) retainers. At the end of treatment, the patient had an acceptable dental alignment with a Class III molar relationship and an improvement in facial appearance.     

下颌第一磨牙缺失两基牙双端固定桥修复的生物力学分析

目的：研究下颌第一磨牙缺失两基牙双端固定桥修复的应力分布。方法：采用CT扫描获取健康成人上、下颌牙及其支持组织二维图像,通过计算机重建技术获得右下颌第一磨牙缺失后的双端固定桥桥体颊舌径分别为正常时的100%、90%、66.7%和50%与右下颌双端固定桥桥体及右下颌第二磨牙颊舌径均分别为正常时的90%、66.7%和50%的7个三维有限元模型,在相同垂直载荷和斜向载荷下分析了基牙牙槽骨高度及桥体大小对固定桥应力分布的影响。结果：当双端固定桥桥体颊舌径分别为正常大小的66.7%和50%时,固定桥两基牙中的第二前磨牙在垂直向加载时均出现明显应力集中;当下颌第二磨牙牙槽骨吸收程度等于及大于35%时,下颌第二前磨牙在其垂直向加载与斜向加载时均出现明显的应力集中,下颌第二磨牙在其垂直向加载时出现明显的应力集中。结论：固定桥受载的Von Mises最大应力集中于连接体表面。对于下颌567双端固定桥,当桥体变窄,颊舌径小于正常大小的66.7%时,有可能会对基牙中的第二前磨牙造成损害。当下颌第二磨牙牙槽骨吸收程度等于及大于35%时,可能对双基牙都造成损害,并可能促使并加速牙槽骨的进一步破坏吸收。     

Rapid maxillary expansion after secondary alveolar bone graft in a patient with bilateral cleft lip and palate.

OBJECTIVE: To verify the effects of rapid maxillary expansion performed after secondary alveolar bone graft in one patient. SETTING: Department of Orthodontics of the Hospital for Rehabilitation of Craniofacial Anomalies, University of Sao Paulo. PATIENT(S): The patient had bilateral cleft lip and palate, had already had a bone graft, and showed a relapsing maxillary constriction in need of correction. INTERVENTION: A fixed dental-mucous-bone-supported expander corrected the maxillary constriction. MAIN OUTCOME MEASURE(S): Measurements were obtained from dental casts, including transverse dimensions (intercanine distance [IC], interfirst premolar distance [IP], and interfirst molar distance [IM]) and measurements of the grafted area (interfirst premolar/central incisors [IPI] and interfirst premolar/canine [IPC]) to observe the changes. Clinical and radiographic analyses were done through direct view. RESULTS: The occlusal radiograph of the maxilla after expansion showed opening of the intermaxillary suture in the premaxillary area, which was clinically confirmed by the diastema between the maxillary central incisors. No radiographic alteration was observed in the grafted area. The transverse measurements of the dental casts (IC, IP, and IM) showed a significant increase. The measurements of the teeth adjacent to the grafted area, IPI and IPC, increased. CONCLUSIONS: The orthopedic effect of rapid maxillary expansion after bone graft was verified. Nevertheless, additional studies are necessary to define any side effects in patients submitted to bone graft.     

Talon cusp associated with other dental anomalies: a case report

Talon cusp is an uncommon dental anomaly referring to an accessory cusp projecting from the cingulum area, or cemento-enamel junction of maxillary or mandibular anterior teeth, in both the primary and permanent dentition. This paper reports a rare case of talon cusp affecting the mandibular right central incisor and maxillary right lateral incisor, together with other dental abnormalities, viz. an inverted impacted migrating mandibular right second premolar; complete agenesis of the maxillary and mandibular third molars, the maxillary right second permanent molar, and the mandibular left permanent central incisor; severe crowding; deep bite; hypoplastic teeth; bilateral reverse cross-bite in the premolar region; and a retrognathic mandible. The presence of this number of dental anomalies in a single patient is rare.     

The evaluation of vertical heights of maxillary and mandibular bones and the location of anatomic landmarks in panoramic radiographs of edentulous patients for implant dentistry

The purpose of this study was to determine variations in the vertical height measurements in the edentulous maxilla and mandible, and to assess positions of the maxillary sinus, mandibular foramen, and the mandibular canal, which are important for implant length selection and planning using panoramic radiographs. The study sample included 346 edentulous alveolar ridges of 90 men and 83 women. Sixty-three dentate patients' panoramic radiographs were used for location of the first premolar and molar area. Panoramic radiographs were made with a Siemens Orthophos panoramic machine which had been standardized previously. All radiographs were made using a standardized manner by the same technician. Fourteen sites were measured on every panoramic radiograph whenever possible, eight sites in the maxilla and six sites in the mandible. Correlation analyses were performed between age groups and all measurements to determine if age is significant as a covariate. In order to examine the effect of gender the statistical analysis of differences between men and women was performed with Student t-test. The 5% significance level was used for statistical significancy. The height of the maxilla and the mandible in the anterior, first premolar, and first molar regions were significantly greater in men than in women. A majority of the most inferior border of the maxillary sinuses was located anterior to the first molar area (premolar regions) both in men (48.9%) and women (55.4%). Although, there was no statistically significant difference between edentulous men and women for the vertical distances from the mental foramen to the alveolar crest, and horizontal distances from mental foramen to midline, there were statistically significant differences between edentulous men and edentulous women for the vertical distances from the upper border of the mandibular canal to the alveolar crest in the first molar area. Mental foramens were located at the crest of the ridge in 7.2% of the edentulous women, and 6.7% of the edentulous men. The results of this study may guide clinicians to make primer decision of implant insertion area for implant supported prosthesis in edentulous patients.     

骨性Ⅲ类错（牙合）牙弓、基骨弓宽度及协调性分析

目的 探讨骨性Ⅲ类错（牙合）患者牙弓、基骨弓宽度及二者协调性,为临床诊断和治疗提供理论依据.方法 选择骨性Ⅲ类错（牙合）患者33例为实验组,47例个别正常（牙合）为对照组,利用锥形束CT扫描颌面部,将扫描后图像导入Mimics10.01图像处理软件分别测量牙弓宽度、基骨弓宽度,并计算上下颌对应宽度之差,对测量结果进行独立样本t检验.结果 骨性Ⅲ类错（牙合）组上颌牙弓宽度与个别正常（牙合）组比较无显著性差异,但下颌牙弓宽度大于正常（牙合）,其中下颌第一磨牙处平均宽度正常（牙合）为（56.26±3.09）mm,骨型Ⅲ类患者为（57.78±3.22）mm,差异有统计学意义（P＜0.05）;骨性Ⅲ类错（（牙合）上颌基骨弓宽度测量值均小于对照组,其中在上颌第二前磨牙处正常（骀）为（59.11±5.97）mm,骨型Ⅲ类患者为（56.23±5.28）mm,有统计学差异（P＜0.05）,下颌基骨弓宽度均大于对照组,其中在前磨牙及第一磨牙处分别为（47.44±2.96）mm、（59.81±3.87）mm和（76.20±4.20）mm,与正常（牙合）相比差异显著（P＜0.05）.骨性Ⅲ类错（牙合）上下颌基骨弓宽度差值均小于正常（牙合）（P＜0.01）,而牙弓宽度差值仅在尖牙处差异显著（P＜0.05）,其余牙位测量项目无统计学差异.结论 ①骨性Ⅲ类错（牙合）组上颌基骨宽度发育不足,下颌基骨宽度发育过度.②骨性Ⅲ类错（牙合）的宽度不协调表现在基骨水平,牙弓对基骨弓宽度不调有代偿.     

The effects of extraction and nonextraction treatment on the mandibular position

Decisions on extraction of teeth as an aid in orthodontic treatment depend on dental and skeletal discrepancies concerning sagittal and vertical relationships. The purpose of this study was to assess the effects of extraction and nonextraction procedures on the posterior rotation of the mandible and the position of gnathion. Forty-eight nonextraction patients and seventy-three extraction patients treated in the orthodontic department were selected. The patients were from 11 to 15 years old, with a mean age of 12 years 2 months. The lateral cephalometric radiographs taken before and after treatment were traced and measured. Eleven variables reflecting the mandibular rotation were selected on the basis of factor analysis. Before treatment, total arch circumferential discrepancy and the 11 selected measurements showed significant differences between the extraction and nonextraction groups. In the extraction group, the lower anterior facial height was larger, ramus height was smaller, and the difference between vertical position of both maxillary and mandibular first molars and posterior facial height was greater than in the nonextraction group. Consequently, the mandible showed posterior rotation and was in retruded position in the extraction group. In the nonextraction group, the type of force application had no significant effect on the changes in skeletal and dental measurements. In the extraction group, however, the type of force application had a significant effect (p less than 0.05) on the changes in total anterior facial height, the horizontal distance of the maxillary first molar to a perpendicular line to the S-N plane passing through point S, the vertical distance of the maxillary molar to the S-N plane, the vertical distance of the maxillary and mandibular first molars to the S-N plane, the difference between the vertical position of the first molars and posterior facial height, and the difference between the vertical position of the first molar and vertical height of the ramus. In the group in which high-pull face-bow headgear was used, the extraction/nonextraction procedures had a significant effect (p less than 0.05) on the changes in angle ANB, total anterior facial height, anterior lower facial height, and the difference between anterior and posterior facial height.(ABSTRACT TRUNCATED AT 400 WORDS)