ABSTRACT
La investigación tuvo como objetivo determinar la influencia de la morfología externa de la raíz de primeros premolares superiores en la existencia de sobreestimación radiográfica durante la preparación para poste. Con este fin se realizó un estudio transversal in vitro, donde 60 premolares superiores uniradiculares fueron instrumentadas con fresas Gates Glidden y Pesso de calibre 1, 2 y 3. Seguidamente se obtuvieron imágenes radiográficas digitales de cada pieza dentaria mediante un aparato posicionador a una distancia constante en sentido vestíbulo lingual, asimismo se realizaron imágenes tomográficas volumétricas de las muestras. En ambas técnicas imagenológicas se midió el espesor a mesial y distal de las piezas. La sobreestimación fue calculada mediante la diferencia de la medida tomográfica menos la radiográfica. Los resultados indicaron que en ambas paredes radiculares hubo diferencia significativa entre las medidas radiográficas y tomográficas (p<0,05), encontrándose en la pared distal diferencias altamente significativas (p<0,001); además se evidenció que la sobreestimación radiográfica fue mayor en la pared distal. El estudio concluyó que existe sobreestimación radiográfica en premolares superiores durante la preparación para poste de un 20,42 % en promedio, siendo la pared distal la estructura que presenta mayor sobreestimación.
SUMMARY: he investigation´s objective was to determine the influence of external morphology of the root of upper first premolars in the existence of radiographic overestimation during preparation for post. An in vitro cross-sectional study was carried out, where 60 single-rooted upper premolars were instrumented with burs. Gates Glidden and Pesso of caliber 1, 2 and 3, then, digital radiographic images of each dental piece were obtained by means of a positioning device at a constant distance in the buccolingual direction; volumetric tomographic images of the samples were also performed. In both imaging techniques, the mesial and distal thickness of the pieces was measured. The overestimation was calculated by the difference of the tomographic measurement minus the radiographic one. The results indicated that in both root walls there was a significant difference between the radiographic and tomographic measurements (p<0.05), with highly significant differences being found in the distal wall (p<0.001); In addition, it was evidenced that the radiographic overestimation was greater in the distal wall. The study concluded that there is radiographic overestimation in upper premolars during post preparation of 20.42% on average, with the distal wall being the structure that presents the greatest overestimation.
Subject(s)
Humans , Bicuspid/diagnostic imaging , Tooth Preparation , Dental Pulp Cavity/diagnostic imaging , Cone-Beam Computed Tomography , Bicuspid/anatomy & histology , Radiographic Image Enhancement , Cross-Sectional Studies , Post and Core Technique , Root Canal Preparation , Dental Pulp Cavity/anatomy & histologyABSTRACT
Objective:To analyze the wall thickness of C-shaped canals in permanent mandibular second molars.Methods:40 ex-tracted permanent mandibular second molars with C-shaped root were collected from native Chinese and were scanned by micro-CT scan-ner.The specimens were reconstructed three-dimensionally by software Mimics 10.01.The roots were sliced from cemento-enamel junc-tion (CEJ)to apex with 1 mm intervals.The cross-sectional root canal configurations were classified into 5 types according to the Fan's Classification.The minimum buccal wall thickness (MBWT),minimum lingual wall thickness(MLWT)and their locations,as well as the wall thickness at the mesial and distal reference sites were detected.Two-way ANOVA and post hoc LSD-t tests were used to com-pare the mean thickness at 4 sides.Results:Among 370 cross-sections of 40 C-shaped roots,C1,C2 and C3 canals were observed on 126(34.1%),46 (12.4%)and 160 (43.2%)sections respectively.Except at the 10 mm level,the mean MLWT was always lower than MBWT;and the MLWT and MBWT were always lower than the wall thickness at the mesial and distal reference sites.The differ-ence was statistically significant (P <0.05)along the root length above the 12 mm level.The MBWT of the C2 and C3 canals was more likely located at the mesial region,and the MBWT of the C1 and the MLWT of C1,C2 and C3 was more frequently located at the center region.Conclusion:The lingual wall of C-shaped canal in mandibualr second molars was the thinnest zone among four sides,and care should be taken during root canal instrumentation and post space preparation to avoid perforation.