Objective: This in vitro study aimed to compare preflaring of three instruments of access with Gates Glidden, IntroFile FlexMaster® and SX ProTaper® used in endodontic treatment. Materials and methods: The preflaring was performed over 30 plastic upper molars (VDW, Germany) standardized which were divided into three groups of ten. Teeth were divided and implemented with Gates Glidden, IntroFile FlexMaster® and SX ProTaper® . This procedure was done by a single trained operator. For measuring the root canals, crowns of teeth were cut transversely to UCA level with a fine diamond disc. Measures corresponding to 5 anatomical references were evaluated: remaining mesial of mesiobuccal canal, vestibular of mesiobuccal canal, mesial of distobuccal canal, vestibular of distal canal and distance between wall of distal of mesiobuccal canal with wall of mesial of distalbuccal canal. The results were analyzed in microns (µm) through a stereomicroscope with a Leica Microsystems 56D software. Results: Statistically significant differences between experimental groups were found. Introfile limes produce minor discrepancy of compensatory attrition. The main discrepancy was found in group 1 (Gates Glidden) unlike the other instruments. Conclusions: The IntroFile FlexMaster® limes present lower cutting angle which produce a conservative preflaring in comparison to Gates Glidden strawberries which produce a more aggressive preflaring. / Objetivo: El presente estudio in vitro tuvo como finalidad comparar el desgaste compensatorio de tres instrumentos de acceso con Gates Glidden, IntroFile FlexMaster® y SX ProTaper®, utilizados en tratamiento endodóntico. Materiales y métodos: Se realizó el desgaste compensatorio sobre una muestra de 30 molares superiores de plástico (VDW, Alemania) estandarizados divididos en tres grupos de 10. Los dientes fueron divididos e instrumentados con Gates Glidden, IntroFile FlexMaster® y SX ProTaper®, lo cual fue realizado por un solo operador capacitado. Para la medición de los conductos radiculares, se cortó transversalmente las coronas de las piezas dentales a nivel de UCA con un disco fino diamantado. Se evaluó las medidas correspondientes a 5 referencias anatómicas que fueron: remanente mesial del conducto mesio vestibular, vestibular del conducto mesio vestibular, mesial del conducto disto vestibular, vestibular del conducto distal y distancia entre la pared distal del conducto mesio vestibular con la pared mesial del conducto vestíbulo distal. Los resultados fueron analizados en micras (µm) a través de un estereomicrooscopio con software (Leica Microsystems 56D). Resultados: Se encontró diferencias estadísticamente significativas entre los grupos experimentales. Las limas IntroFile FlexMaster® producen menor discrepancia de desgaste compensatorio. La principal discrepancia se encontró en el grupo 1 (Gates Glidden) a diferencia de los demás instrumentos. Conclusiones: Las limas IntroFile FlexMaster® presentan menor ángulo de corte por lo que realiza un desgaste compensatorio conservador en comparación con las fresas Gates Glidden que realizan un desgaste compensatorio más agresivo. Objective: This in vitro study aimed to compare preflaring of three instruments of access with Gates Glidden, IntroFile FlexMaster® and SX ProTaper® used in endodontic treatment. Materials and methods: The preflaring was performed over 30 plastic upper molars (VDW, Germany) standardized which were divided into three groups of ten. Teeth were divided and implemented with Gates Glidden, IntroFile FlexMaster® and SX ProTaper®. This procedure was done by a single trained operator. For measuring the root canals, crowns of teeth were cut transversely to UCA level with a fine diamond disc. Measures corresponding to 5 anatomical references were evaluated: remaining mesial of mesiobuccal canal, vestibular of mesiobuccal canal, mesial of distobuccal canal, vestibular of distal canal and distance between wall of distal of mesiobuccal canal with wall of mesial of distalbuccal canal. The results were analyzed in microns (µm) through a stereomicroscope with a Leica Microsystems 56D software. Results: Statistically significant differences between experimental groups were found. Introfile limes produce minor discrepancy of compensatory attrition. The main discrepancy was found in group 1 (Gates Glidden) unlike the other instruments. Conclusions: The IntroFile FlexMaster® limes present lower cutting angle which produce a conservative preflaring in comparison to Gates Glidden strawberries which produce a more aggressive preflaring. / Tesis

Objetivo: Evaluar la asociación de la presencia de alteraciones morfológicas condilares de la articulación temporomandibular con los grados de facetas de desgaste dentario evaluados en tomografías. Materiales y métodos: Un total de 208 tomografías fueron analizadas en este estudio. Se evaluaron las alteraciones morfológicas condilares (osteofito, aplanamiento, erosión, esclerosis, pseudoquiste), así como los grados de facetas de desgaste dentario del 0 al 4 según Hansson y Nilner. Además, se identificaron otras variables como la presencia de mordida abierta, overjet aumentado, overbite aumentado, entre otros. Se utilizó la prueba de Test Exacto de Fisher para evaluar la asociación de las variables y, para el cálculo de las razones de prevalencia crudas y ajustadas se utilizó la regresión de Poisson con varianza robusta.  Resultados: No se encontró asociación entre los grados de faceta de desgaste dentario y la presencia de alteraciones morfológicas condilares. Sin embargo, se observó que a mayor grado de faceta de desgaste hay un incremento en la prevalencia de alteraciones morfológicas. Así, aquellos con Grado 3 de desgaste poseían 36% más probabilidad de presentar alteraciones morfológicas condilares que aquellos con faceta de desgaste Grado 0 (p=0.004).  Conclusiones: Se observó que la presencia de alteraciones morfológicas condilares está relacionada al Grado 3 de desgaste dentario y al sexo femenino. Sin embargo, se sugiere enfocar nuevas investigaciones en la evaluación de Grados 2, 3 y 4 para corroborar lo encontrado. / Objective: The aim of the study was to determine association between the presence of mandibular condyle osseous changes and tooth wear facets evaluated in cone beam computed tomography. Materials and methods: A total of 208 tomography were analyzed. Mandibular condyle osseous changes (osteophyte, flattening, erosion, sclerosis, pseudocyst) were evaluated and tooth wear was assessed between grades 0 to 4 according to Hansson & Nilner, Other variables such as the presence of open bite, increased overjet, increased overbite, among others, were identified. Fisher’s Exact test was used to evaluate association between variables. The crude and adjusted prevalence ratios were performed using the Poisson regression with robust variance. Results: No association was found between tooth wear and presence of mandibular condyle osseous changes. However, these increased as more dental structures got compromised. Thus, individuals with Grade 3 wear were 36% more likely to have mandibular condyle osseous changes than those with Grade 0 wear facet (p = 0.004). Conclusions: Presence of condylar osseous changes of the temporomandibular joint was associated with Grade 3 wear facet and gender. However, further examination of moderate to severe tooth wear is recommended to support the established association. / Tesis