Preliminary Study Of Related Problems On Root Canal Therapy In Molars By Used Of Dental Operating Microscope

Dental operating microscope(DOM) have recently been introduced touse in root canal therapy(RCT). And it was predicted to arise the revolutionof dentistry because of its advantages in visibility and lighting. But theclinician sometimes will doubt that "is it truly use of DOM will help to geta good effect in RCT? ", "How about the sensitivity and specificity ofDOM?", "Does it have any special applicability compare to the generalRCT?"This study focused on the above problems. Firstly a system review ofrelated articles in ten years was done to demonstrate the clinical value ofDOM. Secondly, a diagnostic test was to investigate the sensitivity andspecificity of DOM when it used to located minute details in molars. Lastly,the applicability of microscopic RCT in molars was primary evaluated.This study was expected to offer some useful suggestion to the clinicianand help them to improve the quality of RCT in molars. Part one: System ReviewPreliminary report on searching results of clinical articles ofroot canal therapy under DOM from 1997 to 2006Methods A search was conducted to identify all the clinical studiespublished in English and Chinese related to helpfulness or not when usedDOM in RCTs in resent ten years (1997.1～2006.12). The database includedMedline and CNKI. Then the articles were divided to the two endodonticresidents who read them and assigned an levels of evidence (LOE) for eacharticle independently. And a professor read the article that the two haddifferent opinions and assigned again. The principle of fewness obeymajority was used to settle the dissidence among the three men.Results Based on our inclusion and exclusion criteria, we found 60related articles. 24 of them were expert opinion or literature reviews, 18 ofthem were case reports, another 18 were clinical study. In 18 clinical study,17 researchers (94.4%) thought the use of DOM is helpful in RCT. But ofthese articles, we could not identify any high-level randomized controlstudy. Most of them (70.0%) were low-level studies (LOE-5). Chinesearticles were less than English in ten years (19/41), but the quality betweenthem is closed.Conclusion Most researchers (94.4%) thought the use of DOM is helpfulin RCT. But the levels of these articles were not satisfied enough. Part two: Preclinical StudyDiagnostic test study of dental operating microscopeused for locating the second mesiobuccal canalorifice in maxillary first molarsMethods 120 extracted maxillary first molars were used, all the accesscavities were prepared and fixed on the dental study modal. Onesecond-year-resident-dentist located MB2 orifices with naked eyes andunder DOM at two different time periods. When he finished, anotherresident dentist repeated the test to locate MB2 orifices again with the samemethods. Then India ink was injected into the pulp chamber and all theteeth were cleared to determine if them had real MB2.Results The sensitivity and accuracy of the DOM group were 0.78 and0.76, higher than 0.61 and 0.65 of the naked eyes group (p＜0.05, chisquaretest). The Kappa index for inter-observer agreement was 0.701 and 0.819when used naked eye and under a DOM.Conclusion The use of DOM can increase the detection rate of MB2 inmaxillary first molars. Part Three: Clinical StudyPreliminary study of the suitable coefficient of root canaltherapy in molars by used dental operating microscopeMethods The first 80 consecutive molar cases that presented to theendodontic department of Stomatology Hospital of Jiangshu province forRCT were included in this study. Each tooth number group included 10cases. After accessed the cavities, two residents used DG16 explorer tolocated orifices and evaluated the suitable coefficient of each casesindependently. The standard of suitable coefficient was established by threeexperts consulted the numerical rating scale (NRS) of pain.Results The suitable tooth number for microscopic RCT was maxillary firstmolar, the moderate tooth number was maxillary second molar andmandibular first molar, the unsuitable tooth number was mandibular secondmolar. In a word, maxillary molars were more suitable to do RCT underDOM than mandibular molars, first molars were more suitable than secondmolars, and no difference between left and right.Conclusion Different tooth number have different suitable coefficient inmicroscopic RCT.