MELO, Tiago André Fontoura de; SOARES, Renata Grazziotin; MURARO, Daniele    PREBIANCA, Érica Couto. The analysis of previous radiograph by the operator improves the performance of the apex locator in teeth with root fracture: in vitro study. RFO UPF []. 2013, 18, 3, pp. 302-306. ISSN 1413-4012.

Objective: this study investigated whether the analysis of previous radiograph by the operator influences the performance of the electronic apex locator MiniApex®, upon measuring the working length in teeth with apical root fracture. Materials and method: twenty singlerooted lower premolars were randomly allocated in two groups: GA - teeth with intact root, and GB - teeth with simulated horizontal fracture on the apical third. The working length was determined by visual examination (visual WL) 1 mm shorter from either the total tooth length (GA) or the fracture line (GB). A single operator performed the working length electronic measures (electronic WL) using the 0.5 mark on the device's display. For both groups, the electronic measures were performed in two different moments: phase I - without analysis of previous radiograph, and phase II - with analysis of previous radiograph (measuring the apparent WL with a millimeter ruler). The performance of the apex locator was investigated by comparing each electronic WL measurement to the visual WL, using the Student's t test for data analysis. Results: there was not statistical difference in the GA group regarding the performance of the apex locator for phase I (p = 0.619), as well as for phase II (p = 0.177). There was statistical difference in the GB group for phase I (p = 0.003), but not for phase II (p = 0.489). Conclusion: The analysis of previous radiograph by the operator is imperative for clinical practice, and it improved the performance of the electronic apex locator MiniApex® during the measurement of the WL in extracted teeth with simulated apical root fracture.

: Endodontics; Diagnosis; Tooth fractures; Radiograph; Odontometry.