Full‐Arch Implant‐Supported Fixed Dental Prosthesis Retained by a Combination of Galvano‐Telescopic Copings and Screws: A Clinical Report

Full‐arch screw‐retained implant‐supported fixed dental prostheses have a high long‐term success rate and are considered the gold standard by many clinicians. However, accurate fabrication of a passive fit long‐span prosthesis can be challenging. A novel intraoral adhesion method using galvano‐telescopic copings was proposed as a way of improving prosthetic fit for edentulous patients. This report describes the treatment of a 74‐year‐old female with a full‐arch implant‐supported dental prosthesis, supported by a combination of galvano‐telescopic copings and screws to prevent retention loss. Four years have passed since this superstructure was placed, during this time she exhibited a good clinical course with no inflammation noted in surrounding tissues. Treatment with an implant‐supported fixed dental prosthesis, retained by a combination of galvano‐telescopic copings and screws, can be a useful alternative treatment for edentulous patients.     

矫正第二磨牙锁的2种方法的比较研究

目的评估第二磨牙锁2种矫治方法的优、缺点。方法 38例患者,男22例,女16例随机分成2组,分别使用:一上下牙齿颌间交互牵引,二改良Nance弓,进行矫治。结果经过3～4个月的矫治,上颌第二磨牙正锁解除,上下颌交互牵引所需平均时间为3.75个月,改良Nance弓技术矫正锁平均时间为3.25个月(P<0.05)结论上下颌牙齿交互牵引和改良Nance弓均能解除第二磨牙锁,改良Nance弓技术能更有效快速地解除第二磨牙锁。     

圆锥型套筒冠义齿修复重度牙周炎伴牙列缺损的临床效果评价

目的 评价圆锥型套筒冠义齿修复重度牙周炎伴牙列缺损的临床效果.方法 重度牙周炎伴牙列缺损患者12例,行牙周基础治疗和根管治疗后,采用圆锥型套筒冠义齿修复,记录患者的主观感觉及义齿使用情况.修复前及修复后6个月、1年和3年复诊时,测量并记录牙龈指数(gingival index,CI)和探诊深度(probing depth,PD),实验室检测龈沟液碱性磷酸酶(alkaline phosphatase,ALP)活性.结果 12例患者,圆锥型套筒冠义齿均可正常使用,9例患者对外貌及义齿的使用和语音功能满意,3例基本满意,无不满意.牙龈指数G1在修复后6个月、1年、3年和修复前相比差异无统计学意义(P＞0.05).PD在修复后6个月、1年、3年和修复前相比差异均有统计学意义(P＜0.01).龈沟液ALP活性在修复后6个月和修复前相比差异均有统计学意义(P＜0.01),而在修复后1年、3年和修复前相比差异亦有统汁学意义(P＜0.05).结论 对于重度牙周炎伴牙列缺损,圆锥型套筒冠义齿是一种可行、有效的修复方法,同时也有助于患者牙周状况的改善.     

新型颧弓骨折内固定器的模拟设计及生物力学研究

目的:利用计算机模拟设计一种新型颧弓骨折内固定器,并通过有限元方法对其固定效果进行生物力学分析。方法:利用螺旋CT扫描图像,在Mimics软件中进行颧弓的三维重建,Geomagic软件完成曲面重构,在UG NX5.0中设计新型内固定器并建立颧弓骨折内固定的三维有限元模型,沿X轴正向,对模型外侧进行集中力加载,大小分为10N、30N、60N、90N、120N、150N六个级别,记录分析该有限元模型在不同工况下的应力及位移情况。结果:成功模拟设计出一种新型颧弓骨折内固定器,建立颧弓骨折内固定三维有限元模型,单元数52977,节点数87116。模型应力主要分布在固定器上,模型最大位移部位位于中间骨折段下端,固定器稳定可靠,能提供有效的支撑作用,防止颧弓再移位。结论:模拟的颧弓骨折内固定器固定效果满意,为今后该固定器的设计提供建模基础并对其可行性进行初步验证。     

Linear and Angular Measurements of the Foot of Modern Humans: A Test of Morton'S Foot Types

In his classic research, Morton established two functionally different configurations of the bipedal and non‐bipedal primate foot: one optimized for stability, with a stiff longitudinal arch and adducted first metatarsal, and the other for compliance. Modern human feet were seen as conforming to the bipedal norm and variation from it as pathology, even though clinical evidence has been clear that variation from the norm of a stiff longitudinal arch or adducted first metatarsal exists. This study aims to document the variation in linear and angular measurements of the foot, using weight‐bearing radiographs of 50 randomly selected people (25 men) from an urban US Level 1 trauma center. The radiographs were obtained to “rule‐out” a foot fracture after trauma or as comparison films for a contralateral foot injury. Measurements were made using Osirix and correlations among the angular and length measurements were determined using Stata with P < 0.05 and Bonferroni correction for multiple comparisons. We found that foot length was not correlated with angular measurements, except for the angle between the first and fifth metatarsal. People with lower medial longitudinal arches also had more abducted first metatarsals and more vertical posterior facets, in accordance with Morton's foot types. Whether or not this variation in modern humans is linked to functionally important consequences remains to be determined in future research. With the new evidence of a more variable foot structure in fossil hominins, understanding the relationship between foot morphology and function becomes more urgent. Anat Rec, 296:1526–1533, 2013. © 2013 Wiley Periodicals, Inc.     

Management of ankylosed primary molars with premolar successors: A systematic review

BackgroundThe authors conducted a systematic review to determine the clinical prognosis of and methods of managing ankylosed primary molars with permanent successors.MethodsThe authors searched electronic databases (PubMed, Scopus, MEDLINE, Cumulative Index to Nursing and Allied Health Literature, Web of Science, Cochrane Database of Systematic Reviews and Google Scholar) up to April 2012 with the assistance of a librarian specializing in health sciences databases. They also searched the gray literature. They selected clinical studies in which investigators assessed the prognosis of ankylosed primary molars with permanent successors; they also hand searched references of the selected articles to identify any additional studies that the electronic search may have missed.ResultsThe authors identified 3,529 original articles from the electronic database search and none from the hand search. Once selection criteria were applied, only four articles met all inclusion criteria and were included. The number of patients studied ranged from 15 to 107. The number of ankylosed primary molars investigated ranged from 26 to 263.ConclusionsAnkylosed primary molars often manifest with mild to moderate progressive infraocclusion. Conservative monitoring of ankylosed primary molars is recommended. The clinician should consider extraction if the permanent successor has an altered path of eruption, if the ankylosed primary molar is severely infraoccluded with the adjacent teeth tipping to prevent the successor from erupting, or both. The ankylosed molar often exfoliates spontaneously within six months; however, when exfoliation is more delayed, arch-length loss, occlusal disturbance, hooked roots or impaction of permanent successors may occur.Practical ImplicationsAnkylosed primary molars initially should be monitored closely for up to six months. If they do not exfoliate spontaneously, they should be removed, because arch-length loss, alveolar bone defects, impacted permanent successors and occlusal disturbances often occur when the removal is delayed.     

三段式片段弓技术打开咬合的三维非线性有限元模型的建立及生物力学分析

目的 建立三段式片段弓矫治技术的下颌牙列三维非线性有限元模型,分析计算压低辅弓的力学特性,初步探讨三段式片段弓矫治技术的生物力学特点。方法 利用薄层CT扫描技术,结合Mimics、CATIA、Anasys等专业软件建立含有三段式片段弓下颌牙列三维有限元模型。然后,在所建立的模型上通过Anasys软件中的非线性计算方法分析计算压低辅弓的力学特性及在三段式片段弓作用下下颌牙列的运动趋势和应力分布情况。结果 在5°～ 25°范围内,压低辅弓前端的力值随角度的增加而快速增大;在30°时达到最大（ 0.604 8 N）;在 30°～ 65°范围内,压低辅弓产生的力在0.59 N左右波动。三段式片段弓作用下,下颌侧切牙远中唇向倾斜并向龈方压入;第一磨牙则后倾明显并伴有牙冠的近中颊向远中舌向旋转;其余牙齿基本不发生移动。下颌牙列的应力集中区主要位于侧切牙根的唇侧颈1/3及第一磨牙根分叉处。结论 在适宜压入力的作用下,三段式片段弓技术能有效地压低前牙段,同时控制后牙段的伸长,有利于深覆,特别是高角、露龈笑或成年患者深覆的矫治。     

儿童骨性下颌偏斜患者的牙弓形态及颌骨对称性分析

目的：研究骨性下颌偏斜儿童的牙弓形态,并对颌骨对称性进行分析。方法：选择13例骨性下颌偏斜患者作为研究对象,在模型上以腭中缝为参考标准,测量两侧的牙弓宽度,分析其对称性;在X线片上测量两侧下颌升支高度、下颌体长度及下颌骨综合长度,并进行统计分析。结果：骨性下颌偏斜患者的牙弓形态存在明显的不对称,偏斜侧的牙弓宽度明显大于对侧（P〈0.05）;偏斜侧下颌升支高度和下颌体综合长度明显小于对侧（P〈0.05）,而两侧下颌体长度无明显差异（P〉0.05）。结论：骨性下颌偏斜患者的下颌骨存在明显不对称,牙齿也出现了不同程度的代偿,在临床正畸治疗中,应进行综合分析。     

The Effect of Removable Partial Dentures on Alveolar Bone Resorption: A Retrospective Study with Cone‐Beam Computed Tomography

Purpose: The aim of this study was to compare vertical and horizontal mandibular alveolar bone resorption by measuring bone morphological variation in Kennedy Class II removable partial denture (RPD) wearers and non‐wearers using cone‐beam computed tomography (CBCT). Materials and Methods: In total, 124 sites in the CBCT scans of 62 (29 RPD non‐wearers, 33 RPD wearers) Kennedy Class II patients were analyzed retrospectively. Three‐dimensional representations of the mandible with superimposed cross‐sectional slices were developed with the CBCT scans to evaluate the mandibular alveolar height and width by measuring distances between the mandibular canal, mylohyoid ridge, alveolar crest, and lower border of the mandible in four regions (eight sites) of Kennedy Class II non‐wearers and wearers of RPDs. Results: Mandibular alveolar bone height and width were significantly lower in edentulous sites when compared with dentate sites in both Kennedy Class II non‐wearers and wearers of RPDs (p < 0.05). Additionally, mean vertical and horizontal mandibular bone resorption was significantly higher in RPD wearers than in non‐wearers (p < 0.05). Conclusions: Vertical and horizontal alveolar bone resorption was found to be higher in the RPD wearing patients when comparing the dentate and edentulous sites.