Leakage evaluation of three different root canal obturation techniques using electrochemical evaluation and dye penetration evaluation methods

The aim of this study was to compare the apical sealing ability of three different obturation techniques using an electrochemical evaluation and evaluating dye penetration. One hundred and thirty-two maxillary anterior teeth were randomly divided into six groups. There were 20 teeth in each group. The teeth were obturated as follows: Groups 1 and 4 with Thermafil, Groups 2 and 5 with System B, and Groups 3 and 6 with cold lateral condensation (CLC). The apical leakage in these groups was evaluated using an electrochemical method for Groups 1, 2, 3 and a dye penetration method for Groups 4, 5 and 6. In both methods, the lowest mean leakage values were observed for Thermafil and the highest were observed for the CLC groups. The difference between Thermafil and CLC was statistically significant (P < 0.05). In both groups, System B fillings showed moderate leakage and the difference was not significant with Thermafil and CLC groups.     

Economic evaluation and dentistry

This article is a brief guide to economic evaluation and dentistry. It outlines the most common methods such as cost-effectiveness analysis and cost-benefit analysis; discusses how and when they should be used; gives some dental examples; and outlines important issues that need to be borne in mind when interpreting them. It also corrects one or two common misunderstandings about economic evaluation.     

Presentation and physical evaluation of RadioVisioGraphy

A comparison of physical properties has been made between conventional intraoral films and images made with the RadioVisioGraphy (RVG) system, a unit based on the charged coupled device. The RVG system uses considerably reduced levels of radiation to produce an image immediately after exposure. RVG resolution is slightly lower than that with silver halide emulsion films; however, radiographic information may be increased by electronic image treatment.     

种植体周围炎治疗方法的研究进展

种植体周围炎是牙种植术后常见的并发症之一,可使支持骨丧失、骨性结合失败,甚至导致已经形成骨结合并行使功能的种植体脱落。目前临床上常用的治疗种植体周围炎的方法主要有手术治疗、激光治疗、超声洁治加局部用药单独或联合治疗等。手术治疗可以恢复因炎症导致的骨缺损,较大程度地治疗种植体周围的各种软硬组织损伤;激光治疗便于操作,副作用小并且除菌彻底,越来越被临床医生所重视;洁治加局部用药治疗是传统的治疗方式,疗效好,创伤小易被广大医生及患者接受。各种治疗方法适应症略有不同,针对不同的患者选择最佳的治疗方式是保证治疗成功的关键。     

Temporomandibular joint sound evaluation with an electronic device and clinical evaluation

Sound analysis to diagnose internal derangement has received much attention as an alternative to radiographic examination. The purpose of this study was to compare findings with an electronic device (sonography) and clinical examination to magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ). Twenty-three symptomatic patients (46 joints) were evaluated for this study. All patients had jaw joint pain and one or more of the following findings; limitation of jaw opening, painful mandibular movement with or without clicking or crepitation. The presence or absence of joint sounds was evaluated clinically by palpation and auscultation and with sonography. If sounds were present (clicking or crepitation) on either examination the patient was considered positive for disc displacement for that examination. Two by two tables were constructed comparing sonography and clinical examination with MRI findings. The sensitivity of the sonogram was 84% and the specificity was 33% when compared with MRI findings. The sensitivity of the clinical examination was 70% and the specificity was 40% when compared with MRI findings. This study suggests that clinical and sonographic examination has a high sensitivity (low false negative examinations) but low specificity (high false positive examinations).     

疾病预后的评价及统计学处理

近年来，随着医学的发展，各种新的治疗手段与措施不断用于临床．有关疾病预后的研究越来越受到学者们的重视，但如何客观地选择评价指标与进行统计学处理仍然是一个值得关注的问题。本文主要从目前常用的预后评价指标与应用、影响疾病预后的因素、预后研究的设计与统计学处理等方面进行概述，简要探讨了预后研究中产生偏倚的主要原因，并提出了在预后评价研究时应当引起重视的几个问题。     

Reproducibility and evaluation of gingival indices]

The inflammatory condition of the gingivae may be judged by the anamnestic indication to "gingival bleeding" and by assessing the inflammatory changes by means of the P.M.A. index and the Sulcus Bleeding Index. The patients' indications to gingival bleeding are subjective by nature, but they have proved to be highly reliable when they are obtained by three independent examinators. The testing of the P.M.A. index showed that this method is sufficiently reliable. The Sulcus Bleeding Index was not tested.