RESUMO
AIM: To evaluate several factors that might interfere with the use of electronic root canal length measurement devices (ERCLMDs) in a laboratory setting, including two different embedding media (alginate and electroconductive gel), three different types of devices and the radiographic view on the assessment of the electronic readings. METHODOLOGY: Thirty single-rooted extracted human mandibular premolars were selected. After access and canal pre-flaring, a size 10 K-file was inserted in the canal up to the major apical foramen under magnification (×10), and this length was recorded as the actual length (AL) of the canal. Teeth were mounted on a specific endodontic training kit platform (ProTrain). Two different embedding media (electroconductive gel and alginate) and three different ERCLMDs: Apex ID (SybronEndo, Glendora, CA, USA), CanalPro Apex Locator (Coltene-Endo, Cuyahoga Falls, OH, USA) and the Root ZX II (J. Morita, Tokyo, Japan), were tested. Following the measurement at the 0.5 mark of each ERCLMD using alginate, two periapical radiographs (bucco-lingual and proximal views) were taken. The difference between the electronic readings and the AL, as well as the distance from the file tip to the apex of the roots on the radiographs, was calculated. Data were analysed statistically (two-way anova, Tukey's and chi-squared tests) at 5% significance level. RESULTS: The incidence of over-extended readings was significantly greater (P < 0.05) when using the ProTrain electroconductive gel, except for Root ZX II at the 0.5 mark. Root ZX, CanalPro and Apex ID had similar accuracy when the 0.0/APEX mark was used to locate the foramen. For the radiographic method, no difference was found between the devices or radiographic views. CONCLUSION: Compared with alginate, the conductive gel of the ProTrain kit negatively affected most of the electronic readings. The three evaluated ERCLMDs had similar accuracy in locating the apical foramen when using the mark 0.0/APEX and alginate as the embedding media. Although the ProTrain platform allows radiographs to be exposed in both bucco-lingual and proximal views, no difference was found between the views when evaluating the apical limit provided by the 0.5 mark in mandibular premolars embedded in alginate.
Assuntos
Cavidade Pulpar , Preparo de Canal Radicular , Eletrônica , Humanos , Laboratórios , Odontometria , Ápice Dentário/diagnóstico por imagemRESUMO
AIM: To evaluate in vivo the accuracy of the Root ZX II (J. Morita) apex locator in controlling the apical extent of rotary instrumentation when using the Auto Apical Reverse (AAR) set at the levels 0.5, 1.0 and 1.5. METHODOLOGY: Thirty single-rooted premolar teeth scheduled for extraction were divided into three groups (n = 10), according to the AAR setting 0.5, 1.0 and 1.5. The root canals were prepared using ProTaper (Dentsply Maillefer). After rotary instrumentation, the last file used (F3) was manually introduced into the extent of the root canal preparation and fixed before tooth extraction. The apical third of the root was dissected until exposure of the file. The distance from the file tip to the major apical foramen was obtained. RESULTS: Measurements within the range -1.0 to 0.0 mm were obtained in 30% of the teeth with AAR 0.5, 50% with AAR 1.0 and in 0% with AAR 1.5. The proportions test revealed a significant difference between the AAR settings 1.0 and 1.5 (P = 0.0188). Overinstrumentation occurred in 70% of the teeth with AAR 0.5 and in 40% with AAR 1.0. The measurements short of the acceptable range occurred in 10% of the teeth with setting AAR 1.0 and in 100% of the cases with AAR 1.5. A significant difference was found when comparing the percentage of teeth in which the file tip was short and beyond the established range between groups, except when comparing AAR 0.5 and AAR 1.0. CONCLUSION: The AAR function of the Root ZX II was not an accurate method for controlling the apical extent of rotary instrumentation in vivo. The setting 0.5 presented overinstrumentation in most of the canals, the setting 1.5 was short in all cases, and the setting 1.0 provided an adequate working length in only 50% of the teeth.