阻生智齿在修复下颌磨牙游离端缺失中的利用价值(附120例临床分析)

[目的]观察利用下颌阻生智齿作为基牙修复下颌磨牙游离端缺失的应用效果。方法：120例下颌磨牙游离端缺失拟行可摘局部义齿修复的患者，其中临床研究组60例利用阻生智齿为基牙，另对照组60例则无阻生智齿可利用；行义齿修复后分别跟踪复查，统计其六个月、一年、二年后的修复效果。[结果]临床研究组的咀嚼效能优于后者，随着时间的延长，统计结果具有显著和极显著意义（P〈0．05，P〈0．01）。[结论]利用阻生智齿作为基牙能有效地提高义齿咀嚼效能，对已导致第二磨牙缺失的阻生智齿应予积极保留并使其发挥补偿作用。     

骨性Ⅱ类与Ⅰ类错[牙合]畸形患者第二恒磨牙萌出和钙化时间的比较

目的研究骨性Ⅱ类与骨性Ⅰ类错[牙合]畸形患者第二恒磨牙的萌出位置和钙化时间上的差异。方法对平均年龄为11．2岁的220例患者的治疗前病历资料进行分析,其中19％为骨性Ⅰ类错[牙合]畸形,32％为上颌骨骨性Ⅱ类错[牙合]畸形,49％为下颌骨骨性Ⅱ类错[牙合]畸形。结果各错牙[牙合]形组中第二恒磨牙钙化阶段的分布相近,骨性错[牙合]形类型与第二恒磨牙的发育阶段没有明显相关性。在骨性Ⅱ类错[牙合]畸形组最大年龄组（12岁以上）,上颌第二恒磨牙的萌出位置更偏将向。结论上颌骨骨性Ⅱ类错[牙合]畸形中,上颌第二恒磨牙萌出较早,但钙化时间没有差异。     

直丝弓技术矫治安氏Ⅱ'错(牙合)

总结临床使用直丝弓技术矫治安氏Ⅱ'错(牙合)拔牙病例的疗效,操作要领和注意事项.方法对25例年轻恒牙(牙合)安氏Ⅱ'错采用拔除4)/(4 4)/(4进行直丝技术矫治.结果25例患者平均年龄13.4岁,平均矫治时间24.5个月,矫治完成后均达到理想的侧面外形,磨牙关系由Ⅱ类改为Ⅰ类关系.前牙覆(牙合)覆盖正常,尖窝关系良好,尖牙成Ⅰ类关系.矫治前后头影测量显示ANB角由平均5.5°±2.1°改正为3.1°±1.3°,代表面部软组织侧面外形的Z角由60.5°±5.6°改变为77°±5.8°,代表上下颌矢状关系的AO-BO距离由(6.5±2.3)mm改为(3.1±1.1)mm.结论直丝弓技术矫治Ⅱ'错(牙合),临床效果良好,椅旁操作时间短,值得推广使用.     

直丝弓技术矫治安氏Ⅱ’错He

总结临床使用直丝弓技术矫治安氏Ⅱ'错(牙合)拔牙病例的疗效,操作要领和注意事项.方法对25例年轻恒牙(牙合)安氏Ⅱ'错采用拔除4)/(4 4)/(4进行直丝技术矫治.结果25例患者平均年龄13.4岁,平均矫治时间24.5个月,矫治完成后均达到理想的侧面外形,磨牙关系由Ⅱ类改为Ⅰ类关系.前牙覆(牙合)覆盖正常,尖窝关系良好,尖牙成Ⅰ类关系.矫治前后头影测量显示ANB角由平均5.5°±2.1°改正为3.1°±1.3°,代表面部软组织侧面外形的Z角由60.5°±5.6°改变为77°±5.8°,代表上下颌矢状关系的AO-BO距离由(6.5±2.3)mm改为(3.1±1.1)mm.结论直丝弓技术矫治Ⅱ'错(牙合),临床效果良好,椅旁操作时间短,值得推广使用.     

结扎固定法修复劈裂牙

随着牙体治疗范围的扩大 ,术后引起牙冠劈裂的情况越来越多 ,对此少有可靠的修复方法 ,笔者采用结扎丝固定加光固化充填的方法治疗 10 6例 ,效果满意 ,介绍如下 :1　临床资料1.1　本组 10 6例均为磨牙 ,其中上颌第一磨牙 6 4例 ,下颌第一磨牙 2 3例 ,上颌第二磨牙 10例 ,下颌第二磨牙 9例。1.2　病例的选择　牙髓治疗后无根尖病变且劈裂隙于根分歧以上者为本法适应证。1.3　操作方法1.3.1　用结扎丝于患牙牙颈部做简单结扎 ,等治疗完成后拆除以防操作中劈裂片脱落。1.3.2　将原充填物去除至便于结扎丝穿通结扎为度。1.3.3　打孔　用细裂钻于…     

颞下颌关节疾病与偏侧咀嚼的相关性研究

目的:结合临床病历对偏侧咀嚼和颞下颌关节紊乱病患者的临床特点进行对比分析,探讨偏侧咀嚼与颞下颌关节疾病的相关性.方法:本项研究收集赤峰学院附属医院口腔颌面外科收治的颞下颌功能紊乱病患者病例48例,将有偏侧咀嚼习惯的病例分别与颞下颌关节疼痛、弹响、牙列缺损及阻生智齿四种临床症状的数据做统计学比较,进行X2检验.结果:经统计学计算,偏侧咀嚼分别与颞下颌关节疼痛、弹响、牙列缺损、阻生智齿具有相关性,本次研究结果具有统计学意义.结论:偏侧咀嚼与颞下颌关节疼痛、弹响有正相关关系,牙列缺损和阻生智齿促进偏侧咀嚼习惯的形成.     

下颌第一磨牙远舌根的存在与牙周状态的临床相关性分析：一项采用锥形射束电脑断层扫描分析的横断面研究（英文）

下颌第一磨牙远舌根已经被广泛报道,它的存在使牙周炎的治疗更为复杂。本研究旨在评估中国东部地区人群中下颌第一磨牙远舌根的发生率,并探讨远舌根的形态学特征与骨破坏及牙周状况的关联性。本研究通过对中国东部地区836例患者共1497颗下颌第一磨牙的锥形射束电脑断层扫描（CBCT）进行流行病学分析。其中,69例患者的103颗下颌第一磨牙有完整的牙周检查表。随后采用相关分析和回归分析评估下颌第一磨牙远舌根的形态学特征与骨缺损及牙周临床参数间的关系,包括临床附着缺失、探诊深度、牙龈退缩和根分叉病变情况。研究结果发现,中国东部地区人群中下颌第一磨牙远舌根在患者和牙位水平的患病率分别为29.4%和26.3%。多元线性回归分析表明,第一磨牙舌侧的骨缺损及临床附着丧失水平与位于横截面的远舌根与近中根的分离角呈负相关,而与年龄和位于冠状面上的远颊根与近中根的分离角呈正相关。综上,中国东部地区人群下颌第一磨牙远舌根患病率较高,而且下颌第一磨牙远舌根的形态特征与牙周状况具有相关性。本研究旨在提高下颌第一磨牙远舌根的早期诊断率,并对存在远舌根的第一磨牙的治疗决策提供重要的信息。     

完全性纵折磨牙的保存治疗

目的:探讨牙(牙合)面偏颊或偏舌腭侧1/3至正中1/2完全性纵折磨牙(以下简称完全性纵折磨牙)的保存治疗。方法:采取裂隙冲洗、清创、牙冠结扎、调(牙合)、牙周牙髓联合治疗、分层充填裂隙及冠缺损处,临时冠修复、过渡至金属全冠或烤瓷全冠修复的综合系列治疗,保存上述类型完全性纵折的磨牙。结果:34例患者的39颗完全性纵折磨牙,成功保存35颗,保留时间最长的达16年。结论:牙(牙合)面偏颊或偏舌腭侧1/3至正中1/2完全性纵折的磨牙是折裂牙中比较严重和特殊的一种类型折裂牙,尤其折裂时间长、髓底穿通合并牙龈瘘管,慢性根尖周炎的患牙,经恰当的综合系列治疗和全冠修复后,仍可保存并恢复其咀嚼功能。     

238例下颌阻生智齿并发症临床分析

下颌阻生智齿常引起多种并发症。本文将我科1995～1999年收集的238例下颌阻生智齿及其引起的并发症进行临床分析,目的在于增强对下颌阻生智齿危害性的认识,提高对其并发症的诊治水平,并指出行智齿预防性拔除的必要性。1 临床资料1.1 一般资料 下颌阻生智齿共238例,男125例(52.5%),女113例(47.5%)、年龄为1856岁,多发年龄3040岁。近中阻生124例,     

国人辽宁地区下颌磨牙的活体研究

本研究对238名(男110、女126)年令在18～43周岁,国人辽宁地区青、中年的下颌磨牙1062颗,其中第一磨牙(M_1)476颗,第二磨牙(M_2)476颗,第三磨牙(M_3)110颗进行了观测。测出下颌磨牙的牙尖数,面沟型及牙尖与淘组合型在各类磨牙的分布状志,取得了国人活体的各项数据。在讨论中。从国人活体牙各项数值与国内.外各有关数值进行了比较,得出活体牙与尸牙的异同及人种间的差异,并扼要地进行了解剖学及人类学的探讨。     

上颌斜面导板联合NiTi摇椅弓矫治安氏Ⅱ类一分类错的研究

目的探讨上颌斜面导板联合NiTi摇椅弓在矫治安氏Ⅱ类一分类错畸形的临床疗效。方法选择40例具有生长潜力的安氏Ⅱ类一分类错的青少年患者,在用方丝弓矫治器整平牙弓排齐牙齿后,用上颌斜面导板联合NiTi摇椅弓矫治深覆伴下颌后缩。结果经过6-12个月的治疗,40例安氏Ⅱ类一分类错患者前牙覆覆盖正常,磨牙达到中性关系,咬合良好,面型明显改善。结论上颌斜面导板联合NiTi摇椅弓矫治安氏Ⅱ类一分类错疗效满意。     

国人辽宁地区上颌磨牙的活体研究

本研究对238名(男110女128)年令在18～43周岁,国人辽宁地区青、中年的上颌磨牙1070颗,其中第一磨牙(M_1)476颗.第二磨牙(M_2)476颗,第三磨牙(M_3)118颗进行了观测。测出了上颌磨牙的牙尖型在各类磨牙的分布状态及牙冠的二种退化形式各自表现的特征,取得了各项有关数据;测出了上颌磨牙中各类磨牙的卡氏征阳性率及卡氏征出现各形的频率。讨论中以国人活体牙各项数值与国内、外各有关数值进行了比较,得出活体牙与尸牙的异同及人种间的差异,并对磨牙形态及卡氏征的形态学进行了扼要地探讨。     

A finite element analysis of the stress distribution to the mandible from impact forces with various orientations of third molars

Objective

To investigate the stress distribution to the mandible, with and without impacted third molars (IM3s) at various orientations, resulting from a 2000-Newton impact force either from the anterior midline or from the body of the mandible.

Materials and methods

A 3D mandibular virtual model from a healthy dentate patient was created and the mechanical properties of the mandible were categorized to 9 levels based on the Hounsfield unit measured from computed tomography (CT) images. Von Mises stress distributions to the mandibular angle and condylar areas from static impact forces (Load I-front blow and Load II left blow) were evaluated using finite element analysis (FEA). Six groups with IM3 were included: full horizontal bony, full vertical bony, full 450 mesioangular bony, partial horizontal bony, partial vertical, and partial 450 mesioangular bony impaction, and a baseline group with no third molars.

Results

Von Mises stresses in the condyle and angle areas were higher for partially than for fully impacted third molars under both loading conditions, with partial horizontal IM3 showing the highest fracture risk. Stresses were higher on the contralateral than on the ipsilateral side. Under Load II, the angle area had the highest stress for various orientations of IM3s. The condylar region had the highest stress when IM3s were absent.

Conclusions

High-impact forces are more likely to cause condylar rather than angular fracture when IM3s are missing. The risk of mandibular fracture is higher for partially than fully impacted third molars, with the angulation of impaction having little effect on facture risk.

     

NiTi SMAs的感知驱动特性及在振动控制中的应用

对ＮｉＴｉＳＭＡｓ的感知驱动特性进行了系统的理论分析与实验研究;将不同状态的ＮＩＴｉ ＳＭＡｓ复合于结构中,配以信息处理单元,使结构智能化;实验结果表明这种智能化结构可有效改变自身的动态特性,从而更好的自适应环境。     

Stabilization of an abutment under a rigidly fixed bridge by holographical-speckle interferometry

Objective： There are no detailed reports of three-dimensional measurement of abutment teeth in mastication, because it is knotty to observe the rotation in chewing directly, and inexact to estimate indirectly. This work studies the three-dimensional stability of rigidly fixed bridge under the stresses of distributed loads and concentrated loads by optical method that gives the tip angle and rotation angle calculated directly based on measurement data. Methods： The specimen, taken from a 25-year-old male, was a left mandible without the second premolars and the first molars. As abutments, first premolar and second molar have complete periodontium. The specimen was soaked in formaldehyde solution. The bridge was fixed between two abutment teeth （first premolars and second molars）, and the mandible was cemented in a steel box. The load was increased from 0 kg to 23 kg. Laser holographic technique was used to measure the three-dimensional bit shift of the dens, both buccolingual bit shift and mesiodistal bit shift, and determine tip angle and rotation angle. Results： The effects of stress distribution on the rigidly fixed bridge were evaluated, and stabilization of the bridge under the stresses of distributed loads and concentrated loads, respectively, were analyzed. The results showed that the tips of two abutments were very similar, and no distinct difference was observed between the distributed load and the concentrated load. However, the maximum rotation angle for the distributed load was two to four times as large as that for the concentrated load. In the experiment, the tip angle of the abutment teeth was no more than 0.65 degree, and the rotation angle was no more than 0.60 degree. All maximum angles occurred in the second molar. Conclusion： The fixed bridge is considered to be safe. In addition, a method for measuring the rotation angle was provided effectively.     

NiTi薄膜残余应力测试方法的探讨

介绍了适用薄膜残余应力测量的弯曲法和X射线掠射法,重点介绍了一种新型测量薄膜残余应力的方法—纳米压痕法,并采用非球形压头纳米压痕法测量了NiTi薄膜的残余应力,对薄膜残余应力的测量进行了有益的探讨和尝试,结果表明纳米压痕技术可作为定性测量薄膜残余应力的有效手段。     

Online versus traditional classroom instruction: an examination of developmental English courses at an Alabama community college

A study was conducted at a community college in northeast Alabama to determine how the format of developmental English courses impacted student withdrawal rates and final grades. The two course formats examined were online/hybrid and face-to-face courses. Data were obtained from a 4-semester time frame: fall 2012, spring 2013, summer 2013, and fall 2013. It was determined that students enrolled in the online course were far more likely to withdraw from the course or attain a nonpassing, nontransferable grade than their counterparts who chose the face-to-face course format. The researchers found similar results to larger studies at community colleges in Virginia and the state of Washington.     

Impact of severity of autism and intervention time‐input on child outcomes: comparison across several early interventions

In this article, written by Phil Reed and Lisa Osborne, both from Swansea University, the impact of severity of autism, and the time‐input of the treatment programme, on the outcome effectiveness for four early interventions for individuals on the autism spectrum was explored. The four interventions studied were applied behaviour analysis (ABA), special nursery, an adapted portage intervention, and a local authority approach. Sixty‐six children (aged from two years six months to four years) were studied over nine months, in terms of their intellectual, educational and adaptive behavioural functioning. Children undergoing the ABA approach demonstrated greater gains in functioning (especially in educational functioning). There were differences in the way that autism severity and intervention time‐input impacted on the different early intervention programmes. For special nursery, portage and local authority approaches, the gains made by the children were inversely related to the severity of their autism and directly related to time‐input. In contrast, the converse was true for the ABA approach. These data are discussed with respect to their implications for choosing an intervention strategy for a child on the autism spectrum.     

四手操作技术在儿童恒磨牙窝沟封闭术中的效绩分析

目的：探讨在窝沟封闭术中,四手操作技术与工作效率、封闭脱落率的关系。方法：随机将200例7～9岁无龋病儿童分为四手操作组和医生独立操作组,对第一恒磨牙进行窝沟封闭,比较工作效率、封闭质量、封闭剂脱落率。结果：四手操作组能降低封闭剂脱落率,快速完成操作过程,与独立操作组相比其封闭剂脱落率下降10％,节省操作时间8min。结论：在儿童恒磨牙窝沟封闭术中,四手操作能顺应操作过程,缩短操作时间,提高效率。同时,四手操作能降低封闭剂脱落率,减少医生操作的返工率、重复率,提高治疗质量。