拔牙创内植钛衣磁体及其与骨融合生长的动物试验

本试验设计将2.0×2.0×4.0mm长力体磁体外包一层厚0.5mm金属钛,制成3.0×3.0×5.0mm长方体钛衣磁体,置于犬拔牙创内,恢复牙槽嵴外形,牙龈缝合。两周后检查:拔牙创完全愈合,拔牙创部位牙槽嵴丰满,拍牙片示:钛衣磁体周围无骨质吸收及感染。三月后拍牙X片示:钛衣磁体与颌骨融合。前后测磁力强度无明显变化。一年后拍片示钛衣磁体与骨融合生长,测磁力强度稍减弱。本试验共做4只家犬8个牙位,均获得成功,无一牙失败。结论为:①拔牙创内有钛金属支架利于牙龈爬行生长。②磁体产生的磁场对骨生长愈合有促进作用。③颌骨保持原有高度和宽度,有利于义齿修复并有足够的支承力。④义齿基托内放置相应磁体增加其固位,有利于义齿功能。     

正畸矫治安氏Ⅰ类边缘病例模糊综合评判系统的建立

目的：应用模糊数学方法，从给出明确矫治设计的安氏Ⅰ类拔牙和非拔牙矫治病例中获取信息，将之用于边缘病例的诊断。方法：从给出明确矫治设计的88例安氏Ⅰ类拔牙和非拔牙矫治病例中，随机抽取70例，利用逐步判别分析，获得诊断所需的7项主要指标，用其余18例检验判别函数式，计算各指标的贡献率，建立拔牙与非拔牙集合，构建模糊数学模型。据此模型计算临床病例在两集合中的得分值并根据其值大小确定分类。结果：该模型对15例边缘病例可给出明确诊断，临床诊断符合率为83．3％。结论：模型设计较合理，有较好的临床应用价值。     

牙种植机去骨切割法拔除56颗下颌低位水平阻生牙的体会

应用种植机去骨切割法拔除下颌低位水平阻生牙56颗，同时选取相同年龄范围的56颗下颌低位水平阻生牙，应用高速涡轮钻拔除，以作比较。结果，应用种植机拔除下颌低位水平阻生牙安全、快捷，术后反应和并发症可降至最低，是目前拔除下颌低位水平阻生牙较理想的方法之一。     

拔牙患者牙科焦虑心理研究

目的：研究拔牙患者牙科焦虑心理产生的原因。方法：术前对100例拔牙患者完成问卷，用改良的牙科焦虑量表(corah dental anxiety scale，DAS)和类视力量表(visual anxiety scale，VAS)划界分为高牙科焦虑组和低牙科焦虑组。结果：病人对疼痛的期待存在较大的偏差，高焦虑组更明显。结论：疼痛是病人最恐惧的因素，消除疑虑和减轻疼痛是拔牙术中首要解决的问题。     

拔除第二恒磨牙后第三磨牙自行迁移的临床研究

目的 :探讨第二恒磨牙拔除后第三磨牙自行迁移在水平方向、垂直方向距离变化以及近中倾斜角的改变。方法 :将 2 6例患者分为实验组和对照组 ,实验组拔除第二恒磨牙的患者 15例 ,对照组未拔第二恒磨牙的患者 11例。 2组均拍摄侧位X线头影测量片 ,治疗前和治疗 9个月后测量第三磨牙在水平方向、垂直方向移动距离和近中倾斜度的变化并进行比较。结果 :实验组第三磨牙较对照组在水平方向 ( 7.0 8mm ,2 .0 9mm)移动较快 ,有显著差异 ;在垂直方向 ( 5 .75mm ,1.96mm)移动较快 ,有显著差异 ;其近中倾斜角变化 ( 11.2° ,3 .97°)也有显著意义。结论 :拔除第二恒磨牙加速了第三磨牙的萌出 ,减少了第三磨牙的阻生 ,并使第三磨牙尽快直立 ,并向近中迁移。     

拔牙与不拔牙矫正治疗对牙弓宽度的影响

目的比较拔牙与不拔牙矫正治疗对牙弓宽度的影响。方法选择25例拔除第一或第二前磨牙的正畸患者,25例未拔牙的正畸患者,测量治疗前后的牙颌模型,记录上、下颌牙弓宽度,其中包括尖牙间、前磨牙间及磨牙间宽度,比较拔牙与不拔牙矫正治疗对牙弓宽度的影响。结果上、下颌尖牙牙弓宽度的比较中,拔牙组比不拔牙组大,上颌大1.79mm,下颌大1.95mm,(P<0.01)。磨牙区牙弓宽度差异无显著性。结论拔牙治疗不会导致尖牙区宽度的减小。     

拔除第二双尖牙矫正病例(牙合)颌面的垂直向变化

目的　评价安氏 I类错畸形患者,特别是下颌平面角较大的患者拔除第二双尖牙矫正后颌面的垂直向变化,尤其是下颌平面的旋转变化。方法　24 例覆正常或较浅且下颌平面角大于均值的安氏 I类错患者(骨性与牙性均为 I类)拔除第二双尖牙,应用直丝弓技术完成矫治,25 例符合同样标准的患者由不拔牙矫正完成。对所有病例治疗前后的头颅侧位片进行描图和手工测量,比较拔牙组与非拔牙组颌面垂直向的变化。结果　对拔牙和非拔牙两组患者的头影测量结果进行的统计学比较发现,除下磨牙的伸长量拔牙组大于非拔牙组外,两组患者间颌面垂直向的变化并无统计学意义的差别。结论　第二双尖牙的拔除并不一定意味着下颌平面角的减小,对于高角前牙开倾向病例选择拔除第二双尖牙后,在矫正过程中仍需注意对后牙的垂直向控制。     

Magnesium-enriched hydroxyapatite at immediate implants: a histomorphometric study in dogs

Aim: To evaluate the influence of magnesium‐enriched hydroxyapatite (MHA) (SintLife^®) on bone contour preservation and osseointegration at implants placed immediately into extraction sockets. Material and methods: In the mandibular pre‐molar region, implants were installed immediately into extraction sockets of six Labrador dogs. MHA was placed at test sites, while the control sites did not receive augmentation materials. Implants were intended to heal in a submerged mode. After 4 months of healing, the animals were sacrificed, and ground sections were obtained for histomorphometric evaluation. Results: After 4 months of healing, one control implant was not integrated leaving n=5 test and control implants for evaluation. Both at the test and the control sites, bone resorption occurred. While the most coronal bone‐to‐implant contact was similar between test and control sites, the alveolar bony crest outline was maintained to a higher degree at the buccal aspect of the test sites (loss: 0.7 mm) compared with the control sites (loss: 1.2 mm), even though this difference did not reach statistical significance. Conclusions: The use of MHA to fill the defect around implants placed into the alveolus immediately after tooth extraction did not contribute significantly to the maintenance of the contours of the buccal alveolar bone crest. To cite this article:
Caneva M, Botticelli D, Stellini E, Souza SLS, Salata LA, Lang NP. Magnesium‐enriched hydroxyapatite at immediate implants: a histomorphometric study in dogs.
Clin. Oral Impl. Res. 22 , 2011; 512–517
doi: 10.1111/j.1600‐0501.2010.02040.x     

Five-year evaluation of implants placed at extraction and with dehiscences and fenestration defects augmented with ePTFE membranes: results from a prospective multicenter study

Background: Barrier membranes have been used to promote bone ingrowth on implants with dehiscences and fenestrations. Membranes also have been used to protect defects adjacent to implants placed at the time of extraction. The concept of guided bone regeneration relates to preferentially allowing cells from bone to migrate into various defects while excluding fibrous tissue and epithelium. The purpose of these procedures is to enhance bone-to-implant contact at the treated sites and to prevent mucosal complications. Purpose: The purpose of this article is to report clinical outcomes for implants placed at the time of extraction and augmented with expanded polytetrafluoroethylene (ePTFE) and followed for 5 years. The outcomes for implants with dehiscences and fenestrations augmented with ePTFE barriers and followed up to 5 years also are reported. Methods and Materials: Four treatment centers participated in this study (Tucson, Gothenburg, Spokane, and Leuven). In the extraction group, teeth were removed for varying reasons, and Brånemark implants were placed and stabilized within the host bone. Defects present at the coronal implant aspect were covered with ePTFE barrier membranes. Flaps were rotated to cover the membrane-treated sites. If exposure of the material occurred prior to second-stage surgery, the membranes were removed. Barriers remaining unexposed were removed at second-stage surgery. The implants were followed up to 5 years. In the fenestration and dehiscence group, implants with exposed threads were augmented with ePTFE barrier membranes. The barriers were removed at appropriate intervals, and the patients were followed up to 5 years. Radiographic measurements were made from nonstandardized periapical radiographs at abutment connection and 1, 3, and 5-year follow-up visits. Results: Forty patients participated in the extraction group. They received a total of 49 implants. Three implants failed prior to loading. The 5-year cumulative survival rates for implants placed at the time of extraction were 93.9% and 93.8%, respectively, for maxillary and mandibular implants. The average maxillary mesial and distal marginal bone loss (1–5 yr) was 0.3 mm (standard deviation [SD] = 1.5) and 0.3 mm (SD = 1.0). In mandibles, the average mesial and distal bone loss (1–5 yr) was -0.2 mm (SD = 0.5) and -0.05 mm (SD = 0.6), respectively. The dehiscence and fenestration group included 44 patients. Twenty-six were followed for up to 5 years. Eight patients experienced total implant failure. For dehiscences and fenestrations, the cumulative survival rates were 76.8% and 83.8% for maxillary and mandibular implants, respectively. The average maxillary mesial and distal bone loss (1–5 yr) was 0.4 mm (SD = 0.8) and 0.2 mm (SD = 0.9), respectively. In mandibles, the average mesial and distal marginal bone loss was 0.3 mm (SD = 0.9) and 0.3 mm (SD = 0.8), respectively. Conclusions: Implants placed at the time of extraction and augmented with ePTFE barrier membranes have favorable long-term predictability. On the other hand, long-term evaluation of implant dehiscences and fenestrations augmented with barrier membranes indicates that they have less favorable 5-year survival rates. Membrane augmentation of these may be questioned.     

冠状动脉血管的二维提取和运动跟踪

提出了一种基于图像脊提取和snake模型的复合式方法来实现X射线造影图像序列中冠状动脉血管的二维提取和运动跟踪,并分别对临床采集图像序列和模拟图像进行了实验.结果说明,与经典模型相比本算法自动化程度和精度都提高许多.