C. Abalos

Critical Diameter of Apical Foramen and of File Size Using the Root ZX Apex Locator: An In Vitro Study

INTRODUCTION An evaluation was made of the accuracy of the Root ZX apex locator (J. Morita Corp, Tokyo, Japan) in widened foramina, considering the existing controversy over this issue in the literature. METHODS Ten single-root teeth were embedded in an alginate mold. The foramina were widened from 0.6 mm to 1.0 mm. The measurements were taken with all possible file sizes ≥#10. The statistical accuracy of the Root ZX was calculated for the different diameters and for the influence of file size. RESULTS The accuracy of the Root ZX apex locator with a range of error of ±0.5 mm was 87% in an apical foramen size of 0.6 mm and 84% using files size 45 or larger in an apical foramen size of 0.7 mm. With a tolerance of ±1 mm, the accuracy was 99% in an apical foramen size of 0.6 mm, 98% using files size 45 or larger in an apical foramen size of 0.7 mm, and 95% using files size 70 or larger in an apical foramen size of 0.8 mm. In the rest, accuracy was not certain. The measurements taken with smaller files were shorter. There were no cases of overestimation of the working length. CONCLUSIONS The Root ZX apex locator was accurate for an apical size of 0.6 mm, independently of the file size; between 0.7 to 0.8 mm, we should adjust the files to the foramen, whereas above size 0.9 mm the locator is not accurate. The results show that the accuracy of this electronic apex locator is gradually lost as the foramen widens. Considering the stable conditions of in vitro studies, our findings advise caution in clinical application of the locator.

Retrospective long-term evaluation of autotransplantation of premolars to the central incisor region.

AIM   This retrospective case-series study aimed to examine the long-term outcomes of autogenously transplanted premolars. METHODOLOGY   Twelve patients in whom donor premolars were used to replace maxillary central incisors lost by trauma were clinically and radiologically monitored. Standardized clinical and radiographic records were systematically obtained during the follow-up period of 14 years, to determine the influence of specific clinical criteria on the overall success rate of transplantation. RESULTS   The success rate of premolar autotransplantation in the maxillary central incisor area was 80% after 14 years follow-up. The highest success rate occurred in those teeth transplanted with two-thirds of full root development. Complete pulp obliteration was positively related to autotransplant viability, followed by root formation in the bony crypt. CONCLUSIONS   Autotransplantation of donor teeth, at the stage of ½ to ¾ of their expected root length, can provide a successful treatment solution for over 14 years.

Performance of Laser Fluorescence for Detection of Occlusal Dentinal Caries Lesions in Permanent Molars: An in vivo Study with Total Validation of the Sample

The objective of this in vivo study was to evaluate the performance of a laser fluorescence device in detecting dentinal caries in noncavitated occlusal surfaces. The sample included 102 first and second permanent molars, selected according to the criteria of Ekstrand et al. [Caries Res 1997;31:224–231]: 46 not suspected of having dentinal caries (score: 0–2) and 56 under suspicion (score: 3–4). Once measured by laser fluorescence, all were validated by fissurotomy (gold standard). To avoid ethical questions, the 46 teeth (score: 0–2) used were to serve as abutments for a fixed-fixed bridge. Visual inspection performed well, showing a sensitivity and specificity of 0.93 and 0.88, respectively. Laser fluorescence had an area under the receiver operating characteristic curve of Az = 0.85. The cutoff point with the highest sensitivity and specificity was 20, with a sensitivity and specificity of 0.89 and 0.75, respectively.

How to Diagnose Hidden Caries? The Role of Laser Fluorescence

The diagnosis of pits, grooves and fissures is one of the main challenges facing dentists in their professional activity, since the existence of an intact enamel surface may hide deep caries in dentin. Lesions of this kind were described by Weerheijm et al. (1992) as “hidden caries”. Over 70 years ago a high incidence of caries was confirmed in grooves and fissures (Hyat, 1923), in coincidence with more recent observations (Bragamian & Garcia-Godoy, 2009). In order to understand and explain this high incidence and the morphological peculiarities involved, it is essential to know the physiopathology of the tooth and of the carious lesion.