Aplicabilidad del método Tanaka-Johnston para la estimación del diámetro mesiodistal de caninos y premolares en pacientes de 12-18 Años / Applicability of the Tanaka-Johnston method for the estimation of the mesiodistal diameter of canines and premolars in patients of 12-18 years old

El método Tanaka-Johnston es utilizado mundialmente para predecir el diámetro de caninos y premolares no erupcionados por la conveniencia de no necesitar tablas ni radiografías para su uso. Sin embargo, durante los últimos años investigadores de varios países han demostrado que al ser utilizado en una población diferente para la que fue diseñado, puede sobrestimar o subestimar los valores. En Cuba, donde el patrón facial de la población difiere del ideal para este método, ha sido muy empleado, pero prácticamente no existen estudios donde se valide la confiabilidad o exactitud de las predicciones de este. Por tanto, el objetivo de esta investigación es determinar la aplicabilidad del método Tanaka-Johnston para la estimación del diámetro mesiodistal de caninos y premolares en pacientes de 12-18 años. Se desarrolló un estudio descriptivo y transversal desde junio de 2019 hasta enero de 2020 con una población de 140 pacientes de ambos sexos de entre 12 y 18 años de Cuba. Se efectuaron las mediciones de los anchos mesiodistales de los incisivos inferiores, todos los caninos y premolares. Se realizaron distribuciones de frecuencia a las variables estudiadas y los resultados se presentaron en tablas estadísticas. Para comprobar la existencia de diferencias significativas se utilizó la prueba estadística t-Student. Los resultados principales obtenidos fueron que el método Tanaka-Johnston tiende a sobrestimar los valores para el sexo femenino y subestimarlos para el masculino, ambos entre los 0,2 y 0,3 mm, pero esta diferencia no resulta significativa. Se concluye que el método Tanaka-Johnston puede ser aplicado en la población estudiada para la predicción del ancho mesiodistal de caninos y premolares no erupcionados.

The Tanaka-Johnston method is used worldwide to predict the diameter of canines and premolars not erupted for the convenience of not needing boards or x-rays for use. However, in recent years researchers from several countries have shown that when used in a different population for which it was designed, it can overestimate or underestimate the values. In Cuba, where the facial pattern of the population differs from the ideal for this method, it has been highly used, but there are very few studies where the reliability or accuracy of the predictions of the same is validated. Therefore, the objective of this research is to determine the applicability of the Tanaka-Johnston method for estimating the mesiodistal diameter of canines and premolars in patients aged 12-18 years. A descriptive and cross-cutting study was conducted from June 2019 to January 2020 with a population of 140 patients of both sexes between 12 and 18 years of age from Cuba. Measurements were made of the mesiodistal widths of the lower incisors, all canines, and premolars. Frequency distributions were made to the variables studied and the results were presented in statistical tables. The t-Student statistical test was used to verify significant differences. The main results obtained were that the Tanaka-Johnston method tends to overestimate the values for the female sex and underestimate them for the male, both between 0,2 and 0,3 mm, but this difference is not significant. It is concluded that the Tanaka-Johnston method can be applied in the population studied for the prediction of the mesiodistal width of unerupted canines and premolars.

CBCT assessment of bone thickness in maxillary and mandibular teeth: an anatomic study

Abstract The site of the sinus tract depends on the rate of resistance against abscess exudate drainage, bone morphology, and distance from the root apex to the outer cortical bone. Objective To assess apical bone thickness in buccal and palatal/lingual aspects of maxillary and mandibular teeth, using a high-resolution cone-beam computed tomography (CBCT) system. Methodology In total, 422 CBCT examinations were included in the study, resulting in a sample of 1400 teeth. The scans were acquired by PreXion 3D, with a high-resolution protocol. The bone thickness was taken as the distance between the center of the apical foramen and the buccal and lingual/palatal cortical bone. The quantitative variables were expressed as mean values±standard deviation. The independent samples were analyzed using the t-test or the Mann-Whitney test (p<0.05). Results The lowest mean value of bone thickness was observed in the buccal cortical bone of the upper canines (1.49 mm±0.86) and in the upper central incisors (1.59 mm±0.67). In premolar teeth, the lowest values were found in the buccal cortical bone of upper first premolars (1.13 mm±0.68). In the posterior teeth, the lowest values were found in the buccal cortical bone of upper first molars (1.98 mm±1.33). In the lower second molar region, the buccal cortical bone (8.36 mm±1.84) was thicker than the lingual cortical bone (2.95 mm±1.16) (p<0.05). Conclusions The lowest mean values of bone thickness are in the buccal cortical bone of the maxillary teeth. In the mandible, bone thickness is thinner in the buccal bone around the anterior and premolar teeth, and in the lingual aspect of mandibular molars. All these anatomic characteristics could make the occurrence of the sinus tract more susceptible in these specific regions of the maxillary and mandibular alveolar bone.

In-depth morphological evaluation of tooth anatomic lengths with root canal configurations using cone beam computed tomography in North American population

Abstract Objective This study aimed to assess the association between tooth size and root canal morphology by using CBCT analysis. Methodology In this retrospective study, tooth anatomic lengths (crown and root lengths, buccolingual and mesiodistal dimensions) of 384 patients were assessed and correlated with Vertucci's root canal morphology classification. Data was analyzed for gender-related differences using the independent sample t-test, ANOVA, and the Pearson's correlation for a possible relation between anatomic lengths and canal morphology. Results The maxillary first and second premolars showed a greater predilection for Type IV and II variants, respectively, while the mandibular first premolar showed a greater predilection for Type II canal system. The root canal system of the mandibular second premolar showed maximal diversity (47% Type I, 30% Type II, and 20% Type III). The dimensions were greater in men regardless of tooth type. The most significant relation (p<0.05) between the anatomic size and canal morphology was observed in the maxillary first premolars, followed by the mandibular canines (buccolingual dimension) and the lower second premolars (crown length). Negative correlations existed between the crown length and the patient's age for the anterior teeth and mandibular second premolar (r=−0.2, p<0.01). Conclusions The most common canal formation for anterior teeth was the Type I. The anatomic lengths had the strongest influence on the canal configuration of the maxillary first premolar, with Type IV being the most common root canal system. The mandibular second premolars showed maximal diversity in the canal classification terms and had a significant correlation with their crown lengths. Clinical Relevance The complex relationship between the canal morphology and anatomic tooth sizes need meticulous awareness and recognition during endodontic procedures, in conjunction with the demographic variabilities.

Accuracy of Cone Beam Computed Tomography in the Assessment of Mandibular Molar Furcation Defects

Abstract Objective: To evaluate the accuracy of cone-beam computed tomography (CBCT) in the assessment of mandibular molar furcation defects. Material and Methods: Thirty patients with furcation defects were selected, oral hygiene instructions, scaling, and root planing with ultrasonic devices and hand instruments and occlusal adjustments were performed. Pre-surgical clinical measurements were carried out at the buccal aspect of the selected mandibular molars. The horizontal furcation measurements were measured with a Nabers Probe starting at the furcation entrance to the greatest horizontal depth. The degree of furcation involvement was graded from 0 to III. Bone loss in the horizontal and vertical direction and the width of the furcation entrance were measured on CBCT and after reflecting the full-thickness flap and debridement of the defects. The data were analyzed using t-test and Pearson's correlation coefficient. Results: The width of furcation entrance in clinical method was 3.27 ± 0.77, while in CBCT method was 3.35 ± 0.71, clinically the vertical bone loss was 3.61±1.09, while in CBCT was 3.57 ± 1.15, horizontal bone loss in clinical method was 5.08 ± 2.21, while in CBCT was 5.11 ± 2.23. No significant difference between the two methods was noted, and a high correlation between the two methods was observed. With regards to the agreement between the two methods of assessment, the width of furcation entrance revealed a difference between the two methods by 0.08 ± 0.21, while vertical bone loss showed difference between the two methods by -0.04 ± 0.19, the horizontal bone loss showed a mean difference between the two methods by 0.03 ± 0.21. Conclusion: CBCT provided high accuracy for the furcation involvement detection and anatomy of surrounding periodontal tissues.

Agreement Between Working Length Measurements in Primary Teeth Obtained by Radiographs or Apical Locators

Abstract Objective: To perform an in vivo evaluation on the agreement between measurements of working length obtained by conventional radiographic examinations and an apex locator in deciduous teeth with or without root resorption. Material and Methods: Nine canals of teeth from children ranging from 3 to 5 years old were selected. Endodontic access was performed with a spherical diamond tip, the pulp was removed with Kerr-type steel files, and the canal was irrigated with 1% sodium hypochlorite. A file, compatible with the channel gauge, was then used to measure the length of the root canal with the apex locator. Conventional radiographs were also performed and, using a millimeter endodontic ruler, the length of the canal was determined. The differences between the measurements obtained between the two methods were analyzed using the Student's t-test. Results: The mean canal length for conventional radiography was 9.83 mm and 9.67 mm for the apex locator. The results of this study did not show significant differences (p=0.641), independent of the presence or absence of physiological root resorption. Conclusion: The similarity in measurements obtained with X-ray or an apex locator indicates that it is not necessary to use X-rays as a complement to obtain the working length. The use of the apex locator can provide a quicker treatment, reducing the clinical time and stress of the child.

Estudio preliminar sobre la repetibilidad in vivo de tres localizadores apicales electrónicos / Preliminary study about in vivo repeatability of three electronic apex locators

RESUMEN Introducción: La mayoría de los estudios han evaluado y comparado la exactitud de los localizadores apicales electrónicos pero pocos evaluaron la repetibilidad del método de medición; de estos casi todos son ex vivo. Objetivo: Comparar la repetibilidad in vivo de tres localizadores apicales electrónicos en dientes antero-superiores permanentes. Métodos: Se realizó un estudio observacional analítico de corte transversal en 14 pacientes adultos sanos de ambos sexos con indicación de tratamiento de conductos en una pieza dentaria antero-superior. La selección fue por casos consecutivos. Se utilizaron tres localizadores apicales electrónicos (Root ZX II, Canal Pro y RomiApex A-15) para realizar las mediciones de los conductos. Dos operadores independientes realizaron dos mediciones con cada localizador apical electrónico. Los datos se analizaron por medio de la prueba de Bland-Altman para la repetibilidad y la prueba de Friedman para comparar los localizadores apicales. Resultados: La edad media (desviación estándar) de los pacientes fue 28,79 (± 9,12) años; 8 (57,1 por ciento) pacientes fueron del sexo femenino. La media de las diferencias (límites de concordancia) de las mediciones para Root ZX, Canal Pro y RomiApex A-15 fueron 0,13 mm (± 0,42), 0,12 mm (± 0,88), y 0,18 (± 0,76) mm, respectivamente. Conclusiones. El Root ZX presentó el mayor grado de repetibilidad, seguido por el RomiApex. No se encontraron diferencias estadísticamente significativas entre los localizadores en cuanto a las diferencias absolutas entre la 1ra y 2da mediciones(AU)

ABSTRACT Introduction: Most studies have evaluated and compared the accuracy of electronic apex locators, but few have addressed the repeatability of the measurement method, and most are ex vivo. Objective: Compare the in vivo repeatability of three electronic apex locators in permanent upper front teeth. Methods: An analytic observational cross-sectional study was conducted of 14 healthy adult patients of both sexes with root canal therapy indicated in an upper front tooth. The consecutive case method was used to select the patients. Three electronic apex locators (Root ZX II, Canal Pro and RomiApex A-15) were used for root canal measurement. Two independent operators performed two measurements with each electronic apex locator. Data were analyzed using the Bland-Altman test to assess repeatability and the Friedman test to compare the apex locators. Results: Mean age (standard deviation) of the patients was 28.79 (± 9.12) years; 8 patients (57.1 percent) were female. The mean differences (limits of agreement) of the measurements made by Root ZX, Canal Pro and RomiApex A-15 were 0.13 mm (± 0.42), 0.12 mm (± 0.88) and 0.18 (± 0.76) mm, respectively. Conclusions: Root ZX displayed the highest repeatability, followed by RomiApex. Statistically significant variations were not found between the locators as to absolute differences between the 1st and 2nd measurement(AU)

Comparação das medidas extraorais com as medidas intraorais na confecção da prótese total / Comparison of the extra-oral measurements with the intra-oral measurements in the manufacture of the total prosthesis

Introdução: o edentulismo é um problema bastante comum, e o conhecimento adequado da anatomia e da fisiologia da cavidade oral é essencial na recuperação e no equilíbrio neuromuscular do sistema estomatognático. O uso das linhas de referência juntamente com o plano oclusal orientam o posicionamento dos dentes artificias, que são utilizados para construção das próteses totais. Objetivo: comparar as medidas extraorais com as intraorais da largura dos dentes anteriores com as medidas das linhas de referências preconizadas na literatura para confecção de uma prótese total. Métodos: estudo do tipo observacional transversal, com amostra não probabilística, com 50 indivíduos de ambos os gêneros, no quais se realizou uma análise dentária e facial com auxílio de fotografias e um paquímetro digital. Resultados: foi observado que, na maioria dos indivíduos, não houve coincidência entre a largura dos dentes e as linhas de referência analisadas, que as mulheres apresentaram menor coincidência entre os dentes e a largura da asa do nariz, quando comparadas com os homens (8,3% e 91,7%, respectivamente), com p = 0,001. Conclusão: as linhas de referência não foram coincidentes com o tamanho dos dentes na maioria dos casos avaliados. (AU)

Introduction: edentulism is a fairly common problem, and adequate knowledge of the anatomy and physiology of the oral cavity is essential in the recovery and neuromuscular balance of the stomatognathic system. The use of reference lines together with the occlusal plane guide the positioning of the artificial teeth, which are used to construct the total dentures. Objective: to compare the extra-oral and intra-oral measurements of the width of the anterior teeth with the measurements of the reference lines recommended in the literature for making a total prosthesis. Methods: cross-sectional observational study with a non-probabilistic sample, with 50 individuals of both sexes, where a dental and facial analysis was carried out using photographs and a digital caliper. Results: it was observed that most of the individuals analyzed did not coincide between the width of the teeth and the reference lines, and that the analyzed women showed less coincidence between teeth and the width of the nose wing when compared with men (8.3% and 91.7%, respectively), with p = 0.001. Conclusion: the reference lines did not coincide with tooth size in most cases analysed. (AU)

Comparative Measurement of Tooth Length: Actual vs. Orthopantomography and CBCT-Based Measurements

Objective: To compare the reliability of cone beam computed tomography (CBCT) in assessing the tooth length in comparison to orthopantomography (OPG). Material and Methods: Forty patients scheduled for extraction as result of caries or periodontal involvements were randomly selected. Panoramic radiographs and CBCT images were obtained and subsequently patients were subjected for extraction. Teeth with poor prognosis were extracted and stored in 10% formalin. Radiographic teeth measurements were carried out on OPG and CBCT images using a software and the actual tooth length (A-L) measurements were carried out with a digital vernier caliper. The data collected were statistically analyzed for paired "t" test significance of differences and Pearson's correlation at 5% level of confidence. Results: There was significant difference comparing all three actual tooth length (A-L) and CBCT- and OPG-measured tooth lengths. A significant positive correlation was observed among all the measurements. Conclusion: CBCT images exhibited accuracy over panoramic images even though the measurements are still significantly different from actual anatomical tooth lengths.

Comparison of Two Different Non-Radiographic Mixed Dentition Analysis

Objective: To evaluate the applicability of two different non-radiographic mixed dentition analysis in school going children of Aligarh district, India. Material and Methods: Mesiodistal dimension was measured on the dental casts of 120 school going children with electronic digital vernier caliper. The following inclusion criteria were adopted: presence of all fully erupted permanent teeth; no congenital craniofacial anomalies; no previous history of orthodontic treatment; and presence of intact dentition with no proximal caries, restoration, or age related attrition. Predicted values of canines and premolars were obtained from Moyer's at 75th percentile and Tanaka and Johnston mixed dentition analysis. Descriptive statistics were used to calculate the mean and standard deviation. Paired observations were compared by t­test. The level of significance was at p<0.001. Results: The mean difference between the predicted and the actual value of canines and premolars using Moyer's probability table at 75th percentile and Tanaka and Johnston regression equation were statistically significant. No significant differences were found between Moyer's analysis 75th percentile and Tanaka and Johnston mixed dentition analysis in both arch and sexes. Conclusion: These two non-radiographic mixed dentition analysis overestimated the mesiodistal width of canines and premolars.

Incisor size analysis to predict mesiodistal diameter in unerupted canine and premolar crowns in native and non-native Chilean population / Análisis del tamaño de incisivos para predecir el diámetro mesiodistal de coronas de caninos y premolares no erupcionados en población chilena nativa y no nativa

SUMMARY: The principal orthodontic problems observed in the mixed dentition phase are related to arch length and tooth size discrepancy. In order to identify such space discrepancies different methods of mixed dentition space analyses have been introduced. For this reason the purpose of this study is to generate a new regressive equation to predict the diameter of cuspid and bicuspid teeth through mesiodistal widths of lower incisors in a Chilean population sample between native and non-native population. The study was conducted at the Araucania Dental Clinic in Temuco, and the sample comprised of historical dental casts from 200 school children (93 boys and 107 girls) from Temuco, Chile, between 13-16 years of age. The native Mapuche population consisted of 107 students and the non-native of 93 students. Measurements of the mesiodistal widths of mandibular incisors, maxillary and mandibular canines and premolars were carried out with the help of Vernier gauge calipers calibrated to 0.01 of a millimeter. The results show that there are differences in the mesiodistal diameter size of incisors, and canines and premolars in the two studied groups. There is a low correlation of the variables studied. In conclusion, significant sexual dimorphism in tooth sizes exists in the native sample, and there is no difference in non-native population. It is necessary to develop a predictive formula that is greater than 70 % of accuracy for clinical application. Resonance imaging (MRI).

RESUMEN: El principal problema ortodóncico observado en la etapa de dentición mixta está relacionado con la longitud del arco y la discrepancia del tamaño de los dientes. En orden a identificar tal discrepancia de espacio, diferentes métodos de análisis de espacio en dentición mixta han sido introducidos. Por esta razón el objetivo de este estudio fue generar una nueva ecuación regresiva para predecir el diámetro mesiodistal de caninos y premolares a partir del ancho de los incisivos centrales inferiores en una muestra de población chilena nativa y no nativa. El estudio fue realizado en la Clínica de Ortodoncia Araucanía en Temuco. La muestra fue seleccionada de una colección histórica de modelos dentales, 200 escolares (93 niños y 107 niñas) de la ciudad de Temuco, Chile con edades entre 13 y16 años. La población nativa fueron 107 estudiantes Mapuches y los no nativos fueron 93 estudiantes. Las mediciones del ancho mesiodistal de los incisivos mandibulares, caninos maxilares and mandibulares y premolares fueron realizadas con la ayuda de un medidor Vernier calibrado a 0.01 de milímetro. Los resultados muestran que hay diferencias en el diámetro mesiodistal de incisivos, y caninos y premolares en los grupos estudiados. Hay una baja correlación de las variables estudiadas. En conclusión, hay diferencias significativas en el tamaño de dientes entre hombres y mujeres en la muestra de nativos, y no hay diferencias en la población no nativa. Es necesario desarrollar una fórmula predictiva que sea mayor a 70 % de seguridad para aplicaciones clínicas.

Biometría de dientes anteriores en mestizos: proporción largo/ancho intradental / Biometry of anterior teeth in mestizos: intradental long / wide ratio

Las proporciones largo/ancho intradental han sido propuestas en más de once diferentes modelos a la fecha pero no se han estudiando en población mestiza Colombiana. Se utilizaron modelos de agrupamiento jerárquico (K-Means) para entender cual explica mejor la distribución de los datos. También se analizaron co-variables de sexo, edad y atrición leve para evaluar su influencia sobre la distribución general. Fueron utilizadas fotografías estandarizadas de dientes anteriores de 274 individuos de ambos sexos con dientes completamente erupcionados y sanos. Las mediciones fueron realizadas con programas informáticos calibrados (error de 0,05 mm). Se utilizó la prueba Chi Cuadrado para demostrar que las co-variables el sexo (valor de p= 0,09), edad (valor de p= 0,54) y atrición leve (valor de p= 0,32) no tuvieron impacto en la distribución de las proporciones dentales. Con respecto al análisis de conglomerados a través de las K-Means, se identificaron dos grupos diferenciados en toda la muestra: proporciones verticales (dientes mas largos) y proporciones horizontales (dientes mas anchos). Un tercer grupo solapado entre las dos tendencias lo denominamos de proporciones balanceadas. No hay un modelo de proporción intradental universal que pueda describir toda la población, pero fue posible encontrar un conjunto de modelos para los diferentes subgrupos de población. Los ideales estéticos se encuentran en abierta interpretación. Los patrones absolutos son imprácticos en biología ya que no predicen la complejidad de esta.

The intradental length / width ratios have been proposed in more than eleven different models to date. However they have not been studied in the Colombian Mestizo population. Hierarchical clustering models (K-Means) were used to understand which best explains the distribution of the data. Co-variables of sex, age, and mild attrition were also analyzed to assess their influence on overall distribution. Standardized photographs of anterior teeth of 274 individuals of both sexes with fully erupted and healthy teeth were used. Measurements were taken with calibrated software (error of 0.05 mm). Chi square test was used to show that the co-variables sex (p value = 0.09), age (p value = 0.54) and mild attrition (p value = 0.32) had no impact In the distribution of dental proportions. With respect to the analysis of conglomerates through the K-Means, two distinct groups were identified throughout the sample: Vertical proportions (longer teeth) and horizontal proportions (wider teeth). A third group overlapping the two trends we called balanced proportions. There is no universal intraday proportion model that can describe the entire population, but it was possible to find a set of models for different population subgroups. Aesthetic ideals are in open interpretation. Absolute patterns are impractical in biology because they do not predict the complexity of biology.

Evaluación de un modelo de capacitación preclínica en el uso de los localizadores electrónicos del foramen, por alumnos de grado de endodoncia / Evaluation of a preclinical training model of undergraduatestudents in the use of electronic foramen locatorsin endodontics

Objetivo: evaluar la capacitación y los resultados del uso de localizadores del foramen en un curso preclínico destinado a alumnos de grado de la Escuela de Odontología de la Universidad del Salvador / AsociaciónOdontológica Argentina, entre 2005 y 2016. Materiales y métodos: Se emplearon 2053 incisivos, caninos y premolares inferiores y superiores humanos extraídos. Los dientes se montaron de modo tal que sus raí-ces quedasen sumergidas en una solución salina, utilizando dos métodos: a) tubos de plástico, b) modelos que simulan la arcada dentaria. Se realizaron los accesos coronarios al conducto radicular de forma convencional y se prepararonlos tercios cervical y medio. Para determinar la longitud de trabajo, se introdujo una lima tipo K de calibre acorde con el conducto radicular, ajustando en ella el terminal del localizador electrónico del foramen. El terminal labial se sumergió en la misma solución salina en que se encontraban las raíces dentarias. En la mayoría de los dientes se empleó, parala determinación, la técnica de ingreso, y en los restantes, la de regreso. El nivel de penetración se estableció con la señal lumínica y/o sonora de 0,5. Se ajustó el tope del instrumento al borde de referencia y se obtuvo una imagen radiográfica periapical del diente evaluado. Se retiró el instrumento del conducto radicular y se midió desde su punta hasta el tope respectivo. Las medidas obtenidas con los localizadores electrónicos del foramen se compararon con las conductometrías radiográficas, considerando una tolerancia de 0,5 mm. Para la evaluación estadística, se tomó en cuenta el cálculo de intervalo deconfianza (95 por ciento) realizado a partir de la distribución binomial.Resultados: De los 2053 dientes en los cuales se determinó la longitud de trabajo, 1743 (84,9 por ciento) fueron consideradas medidas correctas, y 310 (15,1 por ciento), incorrectas...

Aim: To assess the training process and results of the useof electronic apex locators in an Aim: To assess the training process and results of the useof electronic apex locators in an undergraduate preclinicalcourse for students from the University del Salvador / AsociaciónOdontológica Argentina between 2005 and 2016.Materials and methods: Two thousand fifty threeextracted human incisors, canines, maxillary and mandibularbicuspid teeth were used. The teeth were mounted withthe roots submerged in saline solution using two methods: a) plastic tubes, b) models simulating the dental arch. Conventionalcoronal access to the root canal was performedand the cervical and middle portions of the root canal wereflared. To determine the working length a K-file with a caliberaccording to the root canal was selected for each tooth andintroduced in the root canal with the clip adjusted in the file.The labial clip was immersed in the model saline solution. Inthe majority of the teeth the advanced and withdrawal techniquewas employed. The level of penetration was establishedusing the light and/or the acoustic signal at 0.5. Then, the rubberstop was adjusted to the reference line and a radiographwas obtained. The instrument was removed and measuredfrom its tip to the rubber stop. The measurements obtainedwith the electronic apex locators were compared with thoseobtained from the X rays considering a tolerance of 0.5 mm.For the statistical evaluation, 95% confidence intervals werecalculated using the binomial distribution.Results: Out of 2053 teeth in which the working lengthwas determined, 1743 (84.9%) were considered correct measurementsand 310 (15.1%) incorrects...

Morfología radicular de los terceros molares / Root canal morphology of third molars

Introducción: la morfología radicular es una característica del tercermolar que puede incrementar el grado de difi cultad de la odontectomía,lo que hace necesario indagar sobre sus aspectos anatómicos más frecuentes. Objetivo: Conocer la morfología radicular de los terceros molares. Material y métodos: Se valoraron 155 tomografías computarizadas cone-beam (TCCB) de pacientes ≥ 16 años de edad, de ambos sexos, con al menos un tercer molar retenido o erupcionado con desarrollo radicular completo. Las características estudiadas fueron el número, longitud, diámetro y forma de las raíces. Resultados: Los terceros molares superiores presentaron con mayor frecuencia raíces fusionadas (57.9 por ciento) en forma cónica sobre su eje (27.2 por ciento). Los casos con raíces separadas mostraron más comúnmente una curvatura hacia distal en el tercio medio de la raíz vestíbulo-mesial (35 por ciento), mientras que la forma predominante de la raíz vestíbulo-distal fue la recta sobre su eje longitudinal (28.8 por ciento). Las formas más frecuentes de la raíz palatina fueron la recta sobre su eje longitudinal y la recta palatinizada conigual número de casos (18.7 por ciento), siendo ésta la que tuvo mayor longitud (11.7 ± 1.7 mm) y diámetro en sus diferentes tercios (cervical 4.8 ± 0.9 mm, medio 4 ± 1.1 mm y apical 2.8 ± 0.9 mm). Los terceros molaresinferiores presentaron mayormente dos raíces (75.9 por ciento) convergentes yseparadas por un septum óseo (38.1 por ciento), siendo la raíz vestíbulo-distal la que presentó mayor diámetro en sus diferentes tercios (4.1 ± 1 mm,3.4 ± 0.7 mm y 2.3 ± 0.6 mm, respectivamente). Conclusiones:Las características de las raíces de los terceros molares observadas en la TCCB se acercan a las descripciones anatómicas. Se observaron, además, múltiples variaciones en su forma, tanto en las fusionadas como en las separadas. Este aspecto morfológico debe ser tomado en cuenta para prever el grado de dificultad de la odontectomía del tercer molar.

Introduction: The root morphology of third molars is something thatcan make extraction more diffi cult, which is why research is needed intothe most common anatomical aspects of this characteristic. Objective:To understand the root morphology of the third molar. Material andmethod: 155 cone-beam computed tomography (CBCT) images ofpatients aged ≥ 16 years of both sexes with at least one retained orerupted third molar with complete root development were examined.The features assessed were: number, length, diameter, and shape ofthe roots. Results: The upper third molar was found to have a greaterfrequency of fused (57.9%) and cone-shaped roots (27.2%). Cases ofseparate roots most commonly displayed distal curvature towards themiddle third of the mesiobuccal root (35%), while the distobuccal rootwas more typically straight along its longitudinal axis (28.8%). Thepalatal root was most commonly either straight along its longitudinalaxis or its palatal side (18.7% in both cases), the latter being longer(11.7 ± 1.7 mm) and having a greater diameter in each of its threesections (cervical 4.8 ± 0.9 mm, middle 4 ± 1.1 mm, and apical 2.8 ±0.9 mm). The presence of two converging roots (75.9%) and two rootsseparated by an interdental septum (38.1%) was more common in lowerthird molars, with the distobuccal root having the greatest diameterin each of its three sections (cervical, 4.1 ± 1 mm, middle, 3.4 ± 0.7mm, and apical 2.3 ± 0.6 mm). Fused roots were longer (11.6 ± 1.8mm) and most commonly cone-shaped with distal tapering (27.7%).Conclusions: The characteristics observed in the CBCT images of theroots of the third molars were similar to those described in anatomicalliterature. Furthermore, multiple variations were found in their shape, inboth the fused and the separate root canals. This morphological aspectshould be taken into consideration in order to determine the degree ofdiffi culty of a third molar extraction.

Acurácia de modelos ortodônticos por escaneamento a laser, luz estruturada e tomografia computadorizada / Accuracy of orthodontic models scanned by laser, structured light, and computed tomography

Introdução: com a crescente utilização dos modelos digitais em Ortodontia, aumenta também a necessidade de se conhecer as opções disponíveis para sua obtenção. Atualmente, a alternativa mais utilizada é o escaneamento de modelos de gesso, que pode ser realizado em scanners a laser, por luz estruturada ou por tomografia computadorizada. O objetivo deste trabalho foi avaliar, através de uma análise por sobreposição de modelos digitais, a acurácia dos modelos digitais gerados por estes três métodos de escaneamento e a influência de dois diferentes níveis de resolução de escaneamento. Material e métodos: 30 pares de modelos de gesso foram escaneados utilizando as três tecnologias. O escaneamento por luz estruturada foi realizado com duas configurações do nível de resolução: máxima e padrão. Os modelos digitais gerados foram sobrepostos e as diferenças entre as superfícies foram calculadas. Mapas de cores foram utilizados para evidenciar as discrepâncias entre os modelos. Resultados: para todos os parâmetros avaliados, foram obtidas diferenças estatisticamente significantes. As diferenças entre os modelos escaneados a laser e por luz estruturada foram menores, o que sugere maior similaridade entre eles. Conclusão: as diferenças encontradas entre os modelos digitais obtidos pelas três tecnologias de escaneamento estudadas foram estatisticamente significantes. No entanto, por serem muito pequenas quantitativamente, não foram consideradas clinicamente significantes. Não houve diferença entre os dois níveis de resolução estudados, portanto, os três métodos de escaneamento avaliados possuem uma acurácia clinicamente aceitável para ser utilizado em Ortodontia.

Introduction: the increasing use of digital models in orthodontics demands knowledge of the available options for their acquisition. Currently, the most used option is the plaster model scanning, which can be made by laser, structured light and computed tomography scanners. The aim of this study was to evaluate, by a model superimposition analysis, the accuracy of digital models acquired by these three scanning methods and the influence of two different resolution levels of scanning. Methods: thirty pairs of plaster models were scanned using three different scanning technologies: laser, structured light and computed tomography. The structured light scanning was performed using two different resolution levels: maximum and standard. The respective digital models were superimposed and their mean differences were compared using color maps by Geomagic Qualify software. Results: for all parameters studied, statistically significant differences were found. Lower differences were presented between models scanned by laser and structured light techniques, which suggests a higher similarity between them. Conclusion: the differences found between digital models obtained by the three scanning technologies were statistically significant. However, they were quantitatively very small, which was considered clinically insignificant. There was no difference between the two resolution levels of scanning studied. Therefore the three scanning methods studied presented accuracy clinically acceptable to be used in orthodontics.

Proporciones del ancho/longitud de las coronas clínicas de los dientes anteriores del maxilar en una población Latino-Americana / Width/length ratios of clinical crowns of maxillary anterior teeth in a Latin-American cohort

Objetivo: Analizar las dimensiones de las coronas clínicas de los dientes anteriores del maxilar con respecto al ancho, longitud y proporción del ancho/longitud; y determinar si existe una correlación entre estos parámetros, así como con la altura facial en una población Latino-Americana. Material y métodos: Este estudio fue observacional de tipo transversal, se seleccionó una muestra de 94 estudiantes de ambos sexos entre 17 y 28 años de edad. Se evaluó en modelos confeccionadosde yeso el ancho, la longitud y la proporción entre ancho/longitud delincisivo central (IC), lateral (IL) y canino (CA) superior derecho, asícomo también se determinó clínicamente la altura facial utilizando un Vernier digital. Resultados: La longitud promedio de las coronas clínicas (en mm) de varones versus mujeres fue del IC: 10.36 versus 9.45; IL: 8.90 versus 8.24 y CA: 10.37 versus 9.43; mientras queel ancho promedio fue del IC: 8.44 versus 8.16; del IL: 7.00 versus 6.78 y del CA: 8.26 versus 8.00. La proporción promedio del ancho/longitud de las coronas clínicas de los varones versus mujeres fue del IC: 0.81 versus 0.86; IL: 0.78 versus 0.82 y CA: 0.80 versus 0.85. Se obtuvieron diferencias signifi cativas del ancho, longitud y la proporción del ancho/longitud de estas coronas por género (p < 0.05). Ademásse encontró una correlación positiva entre las dimensiones de estos dientes, mientras que se obtuvo una correlación relativa con la altura facial. Conclusión: Los resultados indican que en varones y mujeres la proporción del ancho / longitud promedio de las coronas clínicas de los dientes anterosuperiores es 0.82; además del ancho, la longitud de éstos es mayor en los varones y existe una correlación positiva entre las dimensiones dentarias, todo ello nos puede servir como pautas para el plan de tratamiento, procedimientos clínicos estéticos en odontología restauradora para nuestra población.

Objective: To analyze the dimensions of clinical crowns of maxillary anterior teeth in terms of width, length, and width/length ratio, and todetermine whether there is a correlation between these parameters and facial height in a Latin American cohort. Material and methods: Anobservational cross-sectional study was conducted, in which a sampleof 94 students of both sexes, aged between 17 and 28 years old, wasselected. Plaster models were used to measure the width, length, andwidth/length ratio of the central incisor (CI), lateral incisor (LI) andupper-right canine (CA); facial height was also measured using a digital Vernier caliper. Results: The average length of the clinical crowns(in mm) for males versus females was CI: 10.36 versus 9.45; LI: 8.90versus 8.24 and CA: 10.37 versus 9.43; the average width was CI: 8.44versus 8.16; LI: 7.00 versus 6.78 and CA: 8.26 versus 8.00. The averagewidth/length ratio of the clinical crowns of males versus females wasCI: 0.81 versus 0.86; LI: 0.78 versus 0.82 and CA: 0.80 versus 0.85.Signifi cant diff erences in the width, length, and width/length ratio ofthese crowns were found between the sexes (p < 0.05). Furthermore, apositive correlation was found between the dimensions of these teeth,and a relative correlation with facial height. Conclusion: The resultssuggest that, in both men and women, the average width/length ratioof the clinical crowns of upper anterior teeth is 0.82; Furthermore, thewidth and length of these teeth is greater in males and there is a positivecorrelation between the dental dimensions. Together these fi ndingscan serve as guidelines in planning the treatment and clinical aesthetic procedures used in restorative dentistry for our cohort.

Localizador apical electrónico Raypex 6: un estudio in vivo / The Raypex 6 electronic apex locator: an in vivo study

El propósito de ese estudio fue evaluar in vivo la determinación de la longitud de trabajo utilizando el localizador apical electrónico Raypex 6. Material y métodos: Fueron determinadas la longitud de trabajo electrónica (Raypex 6) y radiográfica de 249 conductos radiculares de 125 pacientes con indicación de realizar tratamiento endodóntico. Los pacientes fueron atendidos según los protocolos clínicos habituales. La evaluación fue realizada en dos fases con dos niveles de aceptación, uno con una tolerancia de ± 0.5 mm y otra no. Resultados: En la fase 1 de nivel de tolerancia de evaluación, las mediciones fueron consideradas adecuadas (± 0.5 mm) en el 96.4 por ciento (93.3-98.3), cortos (- 0.5/1 mm) el 1.6 por ciento (04-4) y pasados (+ 0.5/1 mm) el 2 por ciento (0.7-4). Mientras que en la fase 2 de nivel de tolerancia de evaluación para las mediciones consideradas adecuadas (sin rango de tolerancia) fue de un 86.4 por ciento (81.5-91), cortos (- 0.5/1 mm) el 4 por ciento (2-7.8) y pasados (+ 0.5 y a 1 mm) el 9 por ciento (6-13.5). No fueron encontradas diferencias significativas al considerar eldiagnóstico y el género masculino o femenino. Conclusiones: Bajo lascondiciones en que se realizó este estudio la utilización del localizadorapical electrónico Raipex 6 ofreció una aceptable confiabilidad clínica en los dos niveles de tolerancia evaluados...

Use of morphometric analyses to assess the efficacy of the technique of resin composite bonded to cervical dentin with additional mechanical retentions / Uso de análisis morfométrico para evaluar la eficacia de la técnica de resina compuesta unida a dentina cervical con retenciones mecánicas adicionales

The structural changes and morphological derivatives of progressive dentin hypermineralization determine the bonding to its surface. A planimetric study and fracture volume estimate were conducted to assess the efficacy of resin composite bonded to hypermineralized cervical dentin with and without retentions by applying a shear test. Thirty-four premolars from adult patients were used to obtain a flat cervical dentin surface. The specimens were distributed randomly into two groups: 1) experimental, where hemispherical retentions were carved into the cervical dentin, and 2) control, where the flat dentin was maintained. Using a jig, a resin column was built into the dentin surface fitted with bonding in specimens from both groups, which were then subjected to the shear test. The morphological analysis was performed with a microscope while the percentage of remnant surface from each component of the adhesive bond was calculated planimetrically. The volume of lost tissue was determined using Scherle's method. In the planimetric study, the average remnant resin on the surface was significantly higher in the experimental group and there was less intact dentin in the control group. The volumetric assessment also showed a much higher loss of dentin substrate than the experimental group. Consequently, the complementary use of morphometric and volumetric techniques enables the evaluation of the efficacy of a technique, demonstrating that the inclusion of mechanical retentions in hypermineralized cervical dentin improves the bonding properties.

Los cambios estructurales y morfológicos derivados de la hipermineralización dentinaria progresiva determina la adhesión a su superficie. Fue realizado un estudio planimétrico y el volumen de fractura estimado para evaluar la eficacia de resina compuesta adherida a dentina cervical hipermineralizada con y sin retenciones a través de la prueba de cizalla. Treinta y cuatro premolares obtenidos de pacientes adultos fueron utilizados para obtener una superficie dentinaria cervical plana. Las muestras fueron distribuidas aleatoriamente en dos grupos: 1) experimental, donde se realizaron retenciones hemiesféricas a la dentina cervical, y 2) control, donde la dentina plana fue mantenida. Usando un dispositivo, una columna de resina fue construida en la superficie dentinaria y adaptada con adhesivos en las muestras de ambos grupos, las cuales fueron sometidas al test de cizalla. El análisis morfológico fue realizado con un microscopio mientras que el porcentaje de superficie remanente para cada componente del adhesivo fue calculado planimetricamente. El volumen del tejido perdido fue determinado utilizado el método de Scherle. En el estudio planimétrico, el promedio de resina remanente en la superficie fue significativamente mayor en el grupo experimental y con menos dentina intacta en el grupo control. El análisis volumétrico mostró una mayor perdida de sustrato dentinario en el grupo control. De esta manera, el uso de técnicas morfométricas y volumétricas permite la evaluación de la eficacia de una técnica, demostrando que la inclusión de retenciones mecánicas en la dentina hipermineralizada cervical mejora las propiedades de adhesión.

Comparison between Obando´s anthropometric formula and Mondelli´s formula to estimate central incisor width / Comparación entre la fórmula antropométrica de Obando y la fórmula de Mondelli para estimar el ancho del incisivo central superior

Abstract: objective: to compare Mondelli’s formula with Obando’s anthropometric formula in order to determine the mesiodistal width of maxillary central incisor. Materials and Methods: 100 adults (50 women) were selected. The mesiodistal width of maxillary central incisor was measured. Maximum smile was used for Mondelli’s formula. Inter-alar distance and longitudinal axis of the ear were used for Obando’s formula. Correlations and differences between estimates of both formulas and the actual mesiodistal width of the central incisor were estimated. Results: Obando’s formula presented a strong correlation (r=0.8846) with the mesiodistal width, with no statistically significant differences between the two measures (p>0.05). Mondelli’s formula presented a moderate negative correlation with the mesiodistal width (r=-0.3401) and a statistically significant difference with respect to the mesiodistal width (p<0.0001), in both men and women. Conclusion: Obando’s formula estimated more accurately the mesiodistal width of the central incisor in comparison to Mondelli’s formula in the Peruvian population.

Resumen: objetivo: comparar la fórmula de Mondelli con la fórmula antropométrica de Obando para determinar el ancho mesio-distal del incisivo central superior. Materiales y métodos: 100 adultos (50 mujeres) fueron seleccionados. Se procedió a medir el ancho mesio-distal del incisivo central superior. Para la fórmula de Mondelli se utilizó la sonrisa máxima y para la fórmula de Obando se utilizó la distancia interalar y el eje longitudinal de la oreja. Se estimaron correlaciones y diferencias entre las estimaciones de ambas fórmulas y el ancho mesio-distal real del incisivo central. Resultados: la fórmula de Obando presentó una correlación fuerte (r=0,8846) con el ancho mesio-distal, sin diferencias estadísticamente significativas entre ambas medidas (p>0,05). La fórmula de Mondelli presentó una correlación moderada y negativa con el ancho mesio-distal (r=-0,3401) y una diferencia estadísticamente significativa respecto al ancho mesio-distal (p<0,0001), tanto en mujeres como hombres. Conclusión: la formula de Obando logró estimar de manera más precisa el ancho mesio-distal del incisivo central en comparación a la fórmula de Mondelli en población peruana.

Concordancia entre las conductometrías electrónica y radiográfica: un estudio in vivo / Concordance between electronic and radiographic root canal length determination: an in vivo study

Objetivo: valorar la concordancia entre las mediciones realizadas con un dispositivo de localización apical electrónica y las registradas mediante conductometría radiográfica. Materiales y métodos: fueron determinadas las longitudes de trabajo de manera electrónica (RayPex 6, VDW, Alemania) y radiográfica de 249 conducto radiculares correspondientes a 125 pacientes a los que se había indicado tratamiento endodóntico. Estos fueron atendidos según los protocolos clínicos habituales. Resultados: la prueba de t utilizada demostró que la diferencia media entre las mediciones no era significativamente distinta de 0. Los resultados para el coeficiente de correlación interclase y el correspondiente intervalo de confianza indican una concordancia de 0,991 para un intervalo de confianza de 95 por ciento. Concusiones: bajo las condiciones en que fue realizado este estudio, la concordancia entre los valores otenidos con los métodos de determinación de la longitud de trabajo electrónico y radiográfico fue muy buena