Direct and indirect time spent on care of dental trauma: a 2-year prospective study of children and adolescents

Abstract – The aim was to account for the total time spent by professional care‐givers (direct time) and by patients and companions engaged as support and help (indirect time) to treat and otherwise attend to children and adolescents with dental trauma to primary and permanent teeth. The study was based on a random sample of 192 children and adolescents with dental traumas reported to an insurance company and prospectively followed up by telephone interviews over a period of 2 years after the trauma episode. On average, direct time represented 16% of total time for all visits for dental trauma to permanent teeth and 11% for trauma to primary teeth. The most extensive type of indirect time was transport time, which took up 30% of the total time spent on injuries to permanent teeth and 36% for injuries to primary teeth. Multiple regression analysis of the impact of dental and demographic injury variables on the time variables showed that complicated trauma was associated with extended time, direct as well as indirect, for permanent and primary teeth injuries. Our estimate of the average relative increase in total time spent by patients and companions in cases of complicated injury to permanent teeth was 117% (95% confidence interval [CI], 52–211) for patients and 112% (95% CI, 42–217) for companions. For transport time a strong predictor was access to a dental clinic near the place of residence. Lack of access could extend the average transport time by 180% (95% CI, 80–335) for patients and 163% (95% CI, 67–317) for their companions in cases of injuries to primary teeth.     

牙色度分析在原位乳牙脱矿与再矿化检测中的应用

目的:验证数码照相牙色度分析法进行体内乳牙脱矿与再矿化研究的可行性。方法:选取58例平均年龄为4岁的儿童,以左上中切牙为实验牙,先染色、数码拍照,然后对实验牙面进行酸蚀、染色、数码拍照,最后在口腔环境内自然再矿化24h和1周后再染色、拍照,运用图像分析软件进行牙色度R、G、B值分析,比较酸蚀脱矿及再矿化前后牙色度的变化。用SPSS 19.0软件包对数据进行方差分析。结果:酸蚀脱矿后及再矿化24h后的色值(R、G、B)与基值有显著差异(P<0.05);在1周时间点上,只有B值与基值有显著差异(P<0.05);再矿化24h及1周后,牙色度值与酸蚀后相比有显著差异。结论:数码牙色度分析法可识别乳牙脱矿及再矿化前后牙色度的变化,可用于原位乳牙脱矿与再矿化研究。     

桩影响前牙烤瓷冠修复后牙本质应力分布的三维有限元分析

采用三维有限元法分析桩对上颌中切牙金属烤瓷冠修复后牙本质应力分布的影响。选择一标准的上颌中切牙，经包埋、螺旋ＣＴ扫描、图形数字化，采用ＳｕｐｅｒＳＡＰ有限元分析软件在微机上建立三维有限元模型，模拟了牙槽骨、牙周膜、牙本质、桩、金属烤瓷冠的金属帽状冠及烤瓷层等结构，与临床实际结构类似。分别分析ＳＤＡ－Ⅱ型中熔合金桩修复前后，牙本质应力分布情况。结果表明：金属桩可改变牙本质原有的应力分布模式，使桩与牙本质交界区应力值增大；但与此同时又降低了牙本质应力峰值，Ｖｏｎｍｉｓｅｓ应力降低１３．９８％，最大主应力降低７．０５％。即从力学角度提示：合理桩修复可防止牙体断裂。     

Measuring Beliefs about Orthodontic Treatment: A Questionnaire Approach

Objectives : Few studies have examined what parents and orthodontists expect from and value about orthodontic treatment. In this study, we designed and tested a questionnaire to outline what drives consumer demand for children's orthodontic care. Further, we present data from the questionnaire to illustrate how expectations and values pertaining to orthodontic treatment relate to sociodemographic variables. Methods : Subjects were 220 Pennsylvania orthodontists and 220 parents at a university orthodontic clinic who were administered a questionnaire designed to assess what parents and orthodontists value about and expect from orthodontic treatment. Items for the questionnaire were developed via a qualitative, telephone interview process. Data were analyzed using factor analysis and reliability analysis for scale development, and analysis of variance for preliminary validity assessment. Results : Through factor analysis, the questionnaire was reduced from 84 to 52 items, and eight scales were examined: expected treatment benefits, expected treatment risks (short- and long-term), expected treatment inconveniences, value of treatment benefits, value of risks (short- and long-term), and value of treatment inconveniences. For parents, the reliability for all scales was in the acceptable range. For orthodontists, only the “short-term risks” scale failed to attain an acceptable reliability. Preliminary validity was assessed through examining relationships between demographic variables and subscale scores. For parents, income, father's education level, and sex of respondent were related to treatment expectations and values. For orthodontists, age, sex, and patient volume were related to treatment values. Conclusions : The questionnaire developed in the present study was found to be practical and reliable for use with providers and consumers of orthodontic care and can be used to explore factors affecting the demand for orthodontic care. Implications of possible unrealistic treatment expectations on the part of orthodontists and parents also are discussed.     

下颌无牙颌种植固定修复早期负载的临床观察

目的:评价下颌无牙颌种植固定修复早期负载的可行性和临床疗效。方法:14例下颌无牙颌病例共植入94颗ITISLA种植体,种植体植入后第6周完成固定修复。于植入当天、第4周、修复后1年行影像学检查,观察种植部位牙槽骨吸收情况。在植入即刻及第4周行共振频率分析。结果:种植体1年成功率为100%,修复体的1年成功率为100%。影像学检查示种植体周无低密度影;种植部位牙槽骨水平未见明显吸收,均位于种植体第一螺纹的冠方,从全景片测量得1年牙槽骨水平吸收为(0.3±0.94)mm。共振频率分析显示,植入即刻与第4周分别为69.54±4.29和63.14±5.57。结论:ITI SLA种植体固定修复下颌无牙颌早期负载是可行的。     

Cure performance of light-activated composites by differential thermal analysis (DTA)

A technique which utilizes differential thermal analysis and a divided fibre optic system is a valuable aid to the study of the curing behaviour of lightactivated composites. Degree of cure and temperature rise can readily be evaluated as a function of irradiation time. Shade of material, thickness, sample temperature and the presence of porosity all have a significant effect on cure behaviour. The temperature rise for a 60 mm³ sample of material varies between 20°C and 40°C for the materials tested.     

下颌后牙区不同骨质内种植体即刻负载的三维有限元分析

目的 采用三维有限元分析探讨种植体在下颌后牙区不同骨质条件下即刻负载的应力分布,以期为即刻负载的应用选择提供参考.方法 建立下颌后牙区654-|种植体及上部牙冠和牙槽骨的即刻负载模型,根据骨皮质和骨松质比例构成不同分为B1(颌骨完全由均质的骨皮质构成)、B2(3 mm厚骨皮质包绕致密骨松质)、B3(1.5 mm厚骨皮质包绕致密骨松质)、B4(1.5 mm厚骨皮质包绕疏松骨松质)4种骨质条件,模拟颊舌向45°、100 N的力在修复体中心集中加载,分析各种植体在不同骨质内的von Mises应力分布.结果 颊舌向加载后von Mises应力主要集中于种植体颈部舌侧骨皮质,由B1至B4种植体4-|颈周骨内应力平均值[分别为(13.17±9.32)、(12.95±9.14)、(15.00±9.44)、(16.81±10.74)N]和种植体5-|颈周骨内应力平均值[分别为(15.51±10.32)、(14.73±8.96)、(16.79±8.40)、(18.34±8.45)N]的改变趋势一致,B3应力明显高于B1、B2,B4应力明显高于B3(P＜0.05).从B1～B4种植体6-|颈周骨内应力平均值[分别为(42.45±25.71)、(41.66±25.29)、(42.70±23.24)、(42.06±23.66)N]随骨质改变不大,但均显著高于相应骨质内4-|、5-|颈周骨内应力(P＜0.05).结论 在本项实验条件下进行即刻负载,种植体周围应力分布不仅受颌骨骨质的影响,种植体的植入位置以及建立合理的咬合同样非常重要.

Abstract：

Objective To assess and compare the peri-implant stress distribution of three posterior implants under immediate loading with 4 different bone qualities using three dimensional (3D) finite element (FE) analysis. Methods A 3D finite element model representing three implants in a portion of mandible at the 654-| region was developed, and three implants received a crown each. Four types of bone qualities (B1,B2, B3 and B4) were designed for the model. Load of 100 N was applied on the occlusal surfaces of the crowns at a 45° angle to the vertical axis of the implants. Results Von Mises stresses in the peri-implant bone of4-| in bone quality from B1 to B4 were ( 13. 17 ± 9. 32), ( 12. 95 ± 9. 14), ( 15. 00 ± 9. 44 ), and(16.81 ±10.74) MPa, and those of 5-| were (15.51 ± 10.32), (14.73 ±8.96), (16.79 ±8.40), and(18. 34 ±8.45) MPa. Stress in bone quality B4 showed the highest value, followed by B3 bone, the loweststress were found in B1 and B2 bone. It was significantly different (P ＜0. 05). However, von Mises stresses in different quality of bone around 6-| [(42.45 ±25.71), (41.66 ±25.29), (42.70 ±23.24), (42.06 ±23.66) MPa] were close to each other, and were as twice or three times as those of 4-| and 5-| , irrespective of different bone qualities. Conclusions The stress distribution around implant under immediate loading was not only affected by different bone qualities, but also by the direction of loading, and the latter may have a greater impact when a severe load delivered.     

Accuracy in Detecting Artificial Root Resorption in Panoramic Radiography versus Tomosynthetic Panoramic Radiographs

Introduction

The aim of this study was to compare the detection accuracy of panoramic radiography (PAN) and tomosynthetically reconstructed panoramic radiography (TPAN) for the detection of artificial external root resorption in a multiobserver approach.

倾斜基牙的牙周应力分析及修复方法的研究进展

临床修复工作中,近缺隙侧倾斜牙齿常被选作基牙,倾斜基牙所受!力是非轴向力,容易造成牙周组织损伤,如何更加合理有效地利用倾斜基牙进行修复是临床亟待解决的问题。本文就倾斜基牙的牙周应力分析及修复方法作一综述。     

种植体直径和长度在Ⅲ类骨质中的优化选择

目的应用Ansys DesignXplorer模块，分析圆柱形种植体直径和长度同时连续变化时对Ⅲ类骨质的颌骨应力的影响，为临床选择和设计种植体提供理论依据。方法建立包含圆柱状种植体的下颌骨Ⅲ类骨质的骨块三维有限元模型，设定种植体直径变化范围为3．0～5．0mm，种植体长度变化范围为6．0～16．0mm，观察直径和长度变化对颌骨Von Mises应力峰值的影响。同时进行颌骨Von Mises应力峰值对变量的敏感度分析。结果随着直径和长度的增加，垂直向加载时，皮、松质骨的EQV应力峰值分别降低了65．3％和76．8％；颊舌向加载时，皮、松质骨的VonMises应力峰值分别降低了76．1％和78．0％；当直径大于3．95mm，同时长度大于10．5mm时，应力峰值响应曲线的切斜率位于-1和0之间；在垂直向加载和颊舌向加载时，长度和直径分别对皮质骨EQV应力峰值的影响更明显。结论种植体直径增加更有利于改善颌骨颊舌向加载下的应力分布，种植体长度的增加更有利于改善颌骨垂直加载下的应力分布。从生物力学角度而言，对于m类骨质在临床上选择种植体时，种植体的直径应不小于3．95mm。种植体的长度应不小于10．5mm。