Frequency of adequate mesiodistal space and faciolingual alveolar width for implant placement at anterior tooth positions

BackgroundPrior studies have defined minimum mesiodistal space (MS) and faciolingual alveolar width (FAW) requirements for dental implant sites, and failure to observe these constraints may adversely impact peri-implant health and esthetics. However, to the authors’ knowledge, no previous reports have established frequencies at which anterior tooth positions present favorable MS and FAW for implant accommodation.MethodsA single examiner analyzed 205 cone-beam computed tomographic images, recording MS and FAW available for implant placement at anterior tooth positions. The examiner compared measurements with standardized implant diameters to assess anticipated implant-to-tooth distances and peri-implant bone thicknesses.ResultsIn the esthetic zone, lateral incisor sites most frequently failed to present favorable MS. At maxillary lateral incisor positions, 22% (left) and 27% (right) of sites offered less than 2 millimeters between the proposed implant platform and the adjacent teeth. In mandibular incisor positions, implant-to-tooth distance was less than 2 mm at 79% through 97% of sites and less than 1.5 mm at 35% through 76% of sites. Over one-half of maxillary incisor sites and 78% through 95% of mandibular incisor sites exhibited FAW of less than 4 mm beyond implant diameter.ConclusionsIn the population evaluated, mandibular incisor positions frequently presented unfavorable MS to accommodate conventional narrow-diameter implants. In addition, considerable proportions of mandibular incisor and maxillary lateral incisor sites may be at risk of developing unfavorable peri-implant bone thickness when conventional narrow-diameter implants are used.Practical ImplicationsPractitioners should consider small-diameter implants and nonimplant tooth replacement methods for many patients missing single mandibular incisors or maxillary lateral incisors.     

The Buccofacial Wall of Maxillary Sinus: An Anatomical Consideration for Sinus Augmentation

Purpose: This study aimed to quantify the thickness of the buccofacial wall of the maxillary sinus where sinus augmentations are often performed.
Materials and Methods: Fourteen sites located 15 and 20 mm superior to the anatomical cervical line (named as groups H15 and H20, respectively) and along the long axes of the mid and the interproximal of two premolars and two molars were measured from 74 Korean hemiface cadavers.
Results: The buccofacial wall of the maxillary sinus was thinnest at the area between the maxillary second premolar and first molar in groups H15 and H20. The lowest mean thickness was 1.2 mm in both groups. The walls were thicker in males than in females, with statistically significant gender differences found at four and two sites on the anterior horizontal reference in groups H15 and H20, respectively. However, the thickness did not differ significantly with age or laterality. Incomplete septa were found in seven of the 74 specimens, and they were present in the area between the first and second molars in six (86%) of these cases.
Conclusions: These observations indicate that anatomical characteristics of the buccofacial wall thickness of the maxillary sinus need to be considered when performing a window opening procedure for sinus augmentation.     

无牙颌上颌骨缺损修复的体会

目的：探讨单纯修复的方法修复无牙颌上颌骨缺损的效果。方法：对无牙颌上颌骨缺损患者进行分类和不同的修复方法,对疑难的单侧和双侧颌骨缺损采用改良的修复方法。结果：修复后6个月复查,小面积的无牙颌上颌骨缺损,通过常规方法可以获得较好的修复效果;半侧、双侧的无牙颌上颌骨缺损,通过改良的修复法可以提高修复效果。结论：单纯修复方法可以解决一部分无牙颌上颌骨缺损的修复;如果有条件,应该增加其他固位和承力方法;患者自身对赝复体的适应能力在无牙颌上颌骨缺损的修复中很重要。     

激素治疗对阿霉素肾病大鼠上颌骨骨密度的影响

摘要： 目的 研究甲泼尼龙激素治疗对阿霉素肾病大鼠上颌骨骨密度 （BMD） 的影响。方法 将 40 只大鼠随机分为 4 组, 空白对照组、 激素组、 阿霉素肾病组、 阿霉素+激素组。阿霉素肾病组及阿霉素＋激素组采用间隔 1 周 2 次尾静脉注射盐酸阿霉素 4 mg/kg 建立大鼠阿霉素肾病模型, 空白对照组和激素组尾静脉注射生理盐水 4 mg/kg。建模后激素组及阿霉素＋激素组给予甲泼尼龙 30 mg/ （kg·d） 灌胃, 空白对照组及阿霉素肾病组给予等体积生理盐水灌胃。每日 1 次, 连续 10 周。采用酶联免疫吸附试验 （ELISA） 测定骨钙素 （BGP）、 Ⅰ型原胶原 N-端前肽 （PINP）、 β- Ⅰ型胶原交联 C 末端肽 （CTX） 水平; 并行上颌骨 micro-CT 三维扫描检测骨小梁厚度 （Tb.Th）、 骨小梁间隙 （Tb.Sp）、骨小梁数目 （Tb.N）、 骨体积分数 （BVF）、 BMD。结果 与其余 3 组相比, 阿霉素＋激素组 BGP、 PINP 降低, CTX 升高（P＜0.05）。经 micro-CT 三维扫描分析, 阿霉素＋激素组上颌骨发生明显骨质疏松现象, 包括骨显微结构的改变, BMD 降低、 BVF 降低、 Tb.Th 减少以及 Tb.Sp 增宽 （P＜0.05）。但各组 Tb.N 差异无统计学意义。结论 阿霉素肾病大鼠本身存在骨代谢异常, 大剂量激素治疗可加速骨质疏松的发生, 使其骨代谢水平下降, 影响骨小梁结构。     

双磷酸盐药物所致下颌骨坏死研究进展

下颌骨坏死是一种罕见的并发症,被报道曾发生于接受过放疗、化疗及其他肿瘤治疗等多种治疗方法的癌症患者.双磷酸盐是一种强有力的破骨细胞抑制剂,主要用于Paget＇s病、骨质疏松症、多发性骨髓瘤、恶性肿瘤高钙血症、乳腺癌和前列腺癌骨转移.近年来,有关含氮双磷酸盐（帕米磷酸和唑来磷酸）相关性骨坏死的报道日渐增多,其作用机理目前尚不明确.现就双磷酸盐药物致下颌骨坏死的可能作用机制、临床表现、诊断、治疗及预防等相关内容作一综述.     

恒河猴颧骨种植支抗后牵引上颌骨矫形作用的组织学研究

目的：采用颧骨种植支抗后牵引上颌骨,观察在牵引力作用下上颌骨和颧骨周围相关骨缝的组织学变化。方法：生长发育期恒河猴4只,3只用于研究(1只牵引1.5个月、2只牵引3个月),1只作为对照;HE染色和活体骨标记染色,观察上颌骨周围的颧颌缝、横腭缝、翼腭缝、额颌缝以及颧骨后部的颧额缝、颧颞缝、蝶颧缝的组织学变化。结果：上颌骨周围4条骨缝发生明显的以吸收为主的组织学反应。由于骨缝的位置和走向不同,横腭缝、额颌缝表现为骨突顶部吸收为特征的楔形交错性反应;翼腭缝表现为骨突一侧骨表面沉积、另一侧表面骨吸收的位相性反应;颧颌缝兼有2种反应。颧骨后部骨缝呈现牵张状态,观察到骨沉积增加,破骨活动较弱,同样表现出3种不同的骨缝反应。结论：颧骨种植支抗后牵引使上颌骨和颧骨周围骨缝发生了有别于生理性生长改建的明显变化,但未发现破坏性改变。上颌骨周围骨缝组织学反应以吸收为主,不同骨缝组织学反应有所差异,上颌骨因此向后移动并伴有一定的旋转。颧骨后部骨缝发生了与传统口外弓作用不同的牵张成骨反应。     

颊脂垫充填上颌骨囊肿术中拔牙创预防口腔上颌窦瘘

目的: 探讨带蒂颊脂垫转移充填上颌骨囊肿在囊肿摘除加上颌窦根治术中拔牙创效果。方法: 对14例上颌骨囊肿患者在囊肿摘除加上颌窦根治术中拔牙创采用通过上颌窦腔的颊脂垫转移充填。结果: 14例手术均成功,半年后复诊其表面黏膜质地、色泽和周围黏膜不易区分,无张口受限和前庭沟变浅等症状出现。结论: 该手术是一种供区隐蔽、方法简单、并发症少的方法。     

牙槽嵴扩张技术在上颌牙种植中的临床应用

目的　评价牙槽嵴扩张技术在上颌牙种植中的应用效果。方法　对49例牙槽嵴骨量不足的上颌牙种植采用骨扩张器Condenser进行牙槽嵴扩张。根椐不同的缺牙位置,植入与天然牙根直径相当的种植体,以满足患者功能与美学的需要。结果　在49例患者牙槽嵴骨量不足的缺牙区,植入了86枚种植体。术前患者上颌前牙区牙槽嵴宽度平均为3~5·1 mm,术后牙槽嵴宽度平均增加3·3~5·4 mm;术前上颌后牙区,牙槽骨高度平均为6~ 10 mm,术后牙槽骨高度平均增加2~7 mm;种植体均获得初始稳定性;术后6月,X线片显示种植体与牙槽骨形成了紧密的骨性结合骨,种植体植入6个月后进行2期修复。结论　ERE技术适用于上颌牙槽骨扩张,可达到功能与美学的要求,方法简单,值得临床推广。