Estudio Anatómico y Prevalencia del Canalis sinuosus Evaluado Mediante Cone Beam CT en Pacientes Chilenos / Anatomical Study and Prevalence of Canalis sinuosus Evaluated by Cone Beam CT in Chilean Patients

Canalis sinuosus, canal intraóseo localizado en región maxilar anterior, contiene elementos vasculonerviosos alveolares anterosuperiores. Diversas intervenciones en región maxilar anterior como colocación de implantes, exodoncias, instalación de microtornillos ortodóncicos, procedimientos quirúrgicos, entre otros, pueden comprometer al Canalis sinuosus y/o sus canales accesorios dañando los elementos contenidos en su interior causando complicaciones como hemorragias, parestesia, disestesia, etc. Dado el gran desconocimiento de su existencia, el Canalis sinuosus frecuentemente es confundido con lesiones patológicas y/o endodónticas. Clásicamente la literatura lo describe como una variación anatómica variación anatómica, sin embargo, presenta elevadas prevalencias (51,7 %-100 %), siendo cuestionada esta aseveración. Determinar prevalencia y característica s anatómicas del Canalis sinuosus mediante Cone Beam CT en pacientes chilenos del centro radiológico IMAPROX® entre 2017- 2021. Análisis retrospectivo de 220 CBCT maxilares anonimizados, considerando variables sexo, presencia del Canalis sinuosus, Canalis sinuosus uni/bilateral, diámetro mayor del Canalis sinuosus, presencia/número de accesorios. Análisis estadístico uni y bivariado. 100 % de prevalencia del Canalis sinuosus en ambos sexos, presencia bilateral 100 %. Diámetro mayor promedio del Canalis sinuosus: 2,58 mm. El 76,8 % presentó accesorios, siendo más prevalente la presencia de 2 CA (34,1 %). Una estructura anatómica normal habitual debe presentar sobre 50 % de prevalencia para ser considerada como tal, pero no hay consensos en criterios empleados para definir variación anatómica o estructura anatómica normal habitual. Literatura describe al Canalis sinuosus como variación anatómica, pero estudios actuales muestran elevadas prevalencias: Rusia 67 %, Brasil 88 %, Turquía, Colombia y Chile 100 %. Este estudio encontró 100 % de prevalencia, sugiriendo que Canalis sinuosus es una estructura anatómica normal habitual. Sin embargo, Canalis sinuosus es poco conocido asociándose a numerosas complicaciones por procedimientos odontológicos y/o quirúrgicos en RMA pudiendo generar hemorragias, parestesia/disestesia, dolor agudo, etc. Elevadas prevalencias reportadas sugieren que Canalis sinuosus es una estructura anatómica normal habitual y no una variación anatómica, pero se requieren más estudios y consensos para aseverarlo. Es de relevancia clínica conocer la existencia y localización del Canalis sinuosus para evitar complicaciones.

Canalis sinuosus, an intraosseous canal located in the anterior maxillary region, contains anterosuperior alveolar vascular-nervous elements. Various interventions in anterior maxillary region such as implant placement, extractions, installation of orthodontic microscrews, surgical procedures, among others, can compromise the Canalis sinuosus and/or its accessory canals, damaging the elements contained inside, causing complications such as bleeding, paresthesia, dysesthesia, etc. Given the great ignorance of its existence, Canalis sinuosus is frequently confused with pathological and/or endodontic lesions. Classically, the literature describes it as an anatomical variation, however, it presents high prevalence (51.7 %-100 %), this assertion being questioned. Objective: to determine the prevalence and anatomical characteristics of Canalis sinuosus using Cone Beam CT in Chilean patients from the IMAPROX® radiological center between 2017-2021. Retrospective analysis of 220 anonymous maxillary CBCT, considering variables sex, presence of Canalis sinuosus, uni/bilateral Canalis sinuosus, largest diameter of Canalis sinuosus, presence/number of accessory canals. Univariate and bivariate statistical analysis. The 100 % prevalence of Canalis sinuosus in both sexes, 100 % bilateral presence. Canalis sinuosus average major diameter: 2.58 mm, 76.8 % presented accessory canals, with the presence of 2 accessory canals being more prevalent (34.1 %). A habitual normal anatomical structure must have a prevalence of over 50 % to be considered as such, but there is no consensus on the criteria used to define anatomical variation or normal anatomical structure. Literature describes Canalis sinuosus as anatomical variation, but current studies show high prevalence: Russia 67 %, Brazil 88 %, Turkey, Colombia and Chile 100 %. This study found 100 % prevalence, suggesting that Canalis sinuosus is an normal anatomical structure. However, Canalis sinuosus is little known as it is associated with numerous complications from dental and/or surgical procedures in anterior maxillary region, which can cause bleeding, paresthesia/ dysesthesia, acute pain, etc. High reported prevalences suggest that Canalis sinuosus is an normal anatomical structure and not an anatomical variation, but more studies and consensus are required to confirm this. It is clinically relevant to know the existence and location of Canalis sinuosus to avoid complications.

Assessment of root canal anatomy of maxillary and mandibular canine teeth: a cone-beam computed tomography study / Evaluación de la anatomía del canal radicular de caninos maxilares y mandibulares: un estudio de tomografía computarizada de haz cónico

Abstract To investigate the root canal anatomy of permanent maxillary and mandibular canines in a Turkish subpopulation using cone beam computed tomography (CBCT). Retrospective CBCT data of 300 patients admitted to our clinic between 2016 and 2018 were screened and evaluated. A total of 235 patients, 100 males and 135 females, aged 14-76 years (mean age 37.27±13.40) were included in this study. A total of 191 (44,8%) maxillary canine teeth and 235 (55,2%) mandibular canine teeth were examined. The number of roots and root canal morphology according to Vertucci's classification, the presence of accessory canals, and the position of the apical foramen of the root were analyzed. The effect of gender and age on the incidence of root canal morphology was also investigated. The majority of the teeth had a Type I canal configuration in both maxillary canines (100%) and mandibular canines (92,8%). In the mandibular canines the other canal patterns found were Type III (6,8%), and Type II (0,4%). Apical foramen was centrally positioned in the majority of the teeth, 70,2% and 66,8% in maxillary and mandibular canines, respectively. The occurrence of two roots in mandibular canines was 3,8% and the root canal separation was found 53,8% and 46,2% in the middle and cervical third of the root, respectively. No significant statistical difference was observed effect of gender and age on the incidence of the root canal morphology and the position of the apical foramen. Due to the diverse morphology and the potential presence of a second canal for canine teeth among the Turkish subpopulation, dentists should perform endodontic treatments with greater care. CBCT is an accurate tool for the morphological assessment of the root canals.

Resumen Investigar la anatomía del conducto radicular de los caninos maxilares y mandibulares permanentes en una subpoblación turca utilizando la tomografía computarizada de haz cónico (CBCT). Se examinaron y evaluaron los datos CBCT retrospectivos de 300 pacientes ingresados en nuestra clínica entre 2016 y 2018. Un total de 235 pacientes, 100 hombres y 135 mujeres, de entre 14 y 76 años (edad media de 37,27±13,40) fueron incluidos en este estudio. Se examinaron un total de 191 (44,8%) dientes caninos maxilares y 235 (55,2%) dientes caninos mandibulares. Se analizó el número de raíces y la morfología del conducto radicular según la clasificación de Vertucci, la presencia de conductos accesorios y la posición del foramen apical de la raíz. También se investigó el efecto del sexo y la edad en la incidencia de la morfología del conducto radicular. La mayoría de los dientes tenían una configuración de conductos de tipo I tanto en los caninos maxilares (100%) como en los caninos mandibulares (92,8%). En los caninos mandibulares los otros patrones de conductos encontrados fueron el Tipo III (6,8%) y el Tipo II (0,4%). El foramen apical estaba situado en posición central en la mayoría de los dientes, 70,2% y 66,8% en los caninos maxilares y mandibulares, respectivamente. La ocurrencia de dos raíces en los caninos mandibulares es del 3,8% y la separación del conducto radicular se encontró en el tercio medio y cervical de la raíz en el 53,8% y el 46,2%, respectivamente. No se observó ninguna diferencia estadística significativa en el efecto del sexo y la edad sobre la incidencia de la morfología del conducto radicular y la posición del foramen apical. Debido a la diversa morfología y a la posible presencia de un segundo conducto en los dientes caninos entre la subpoblación turca, los odontólogos deberían realizar los tratamientos endodónticos con mayor cuidado. La CBCT es una herramienta precisa para la evaluación morfológica de los conductos radiculares.

Esthetic proportions of maxillary anterior tooth among 300 normal occlusion college students in Shanxi province / 中华口腔医学杂志

Objective: To explore the relationship between the width ratios of maxillary anterior teeth, the width/height ratios of maxillary central incisor and the esthetic proportions among individual normal occlusion, and to provide reference for the esthetic design of anterior teeth. Methods: A total of 300 Shanxi Medical University students who were residents from Shanxi province with normal occlusion (110 males, 190 females, aged 18-30 years) were recruited in this study from October 2020 to March 2021. Standardized digital photographs of the maxillary anterior tooth in natural head position were obtained, the perceived width of the maxillary anterior teeth (maxillary central incisors, lateral incisors and canines) on the left and right sides and height of maxillary central incisor were measured on the standardized digital photographs, then the width ratios of adjacent maxillary anterior teeth including the lateral incisor/central incisor width ratio (LI∶CI), the canine/lateral incisor width ratio (C∶LI), and the width/height ratios (W/H ratio) of the maxillary central incisor were calculated. The independent sample t test was used to compare the sex differences of each measurement project, Single sample t test was used to compare the difference of adjacent maxillary anterior teeth width ratios with golden proportion (0.618 and 0.618), Preston proportion (0.66 and 0.84), the recurring esthetic dental (RED) proportion (0.70 and 0.70). The percentage of anterior tooth width/intercanine width was calculated, the number and proportion of teeth conforming to golden percentage (25%, 15%, 10%)±1% or modified golden percentage (22.5%, 15.0%, 12.5%)±1% were calculated. The number and proportion of width/height ratio of maxillary central incisor ranged from 0.75 to 0.85 was counted. Results: The widths of maxillary central incisor, lateral incisor and canine were (8.50±0.52), (6.23±0.53) and (5.18±0.55) mm, respectively, the corresponding tooth of male [(8.74±0.49), (6.37±0.52), (5.41±0.47) mm] was significantly higher than that of female [(8.37±0.50), (6.15±0.52), (5.04±0.54) mm] (t=6.40, 3.55, 6.23,P<0.05). The width ratio of maxillary lateral incisor/central incisor was 0.73±0.05, and there was no significant difference between genders (t=-1.06, P>0.05). The width ratio of canine/lateral incisor was 0.84±0.10, and it was significantly higher in male (0.85±0.10) than in female (0.82±0.10) (t=2.42, P<0.05). Two width ratios of maxillary anterior teeth were significantly different from golden proportion and the RED proportion (t=38.50, 35.74, 11.48, 22.20, P<0.05). The lateral incisor/central incisor was significantly different from that of Preston proportion (t=24.66, P<0.05), while the canine/lateral incisor was not significantly different from that of Preston proportion (t=-0.92, P>0.05). In this study, a total of 0% (0/600) of central incisors, 63.0% (378/600) of lateral incisors and 5.8% (35/600) of canines met the golden percentage±1%. There were 42.8% (257/600) of central incisors, 63.0% (378/600) of lateral incisors and 56.7% (340/600) of canines met the modified golden percentage±1%. The width/height ratio of maxillary central incisors was 0.86±0.08, and there was no significant difference between genders (t=-0.88, P>0.05). Only 36.3% (218/600) of the subjects in this study ranged from 0.75 to 0.85. Conclusions: Gender differences should be considered in the esthetic design of anterior teeth; for the width ratios of maxillary anterior teeth, the golden proportion, the RED proportion and golden percentage do not accord with the natural tooth morphological characteristics of Shanxi nationality college students in normal occlusion. Preston proportion and modified golden percentage are of more reference value. The width/height ratio of maxillary central incisors is different from 0.75-0.85.

Morfología ósea facial en cirugía ortognática. ¿existe tendencia hacia el avance facial? / Facial morphology in orthognathic surgery: is there a facial advance trend?

RESUMEN: El objetivo de esta investigación fue determinar los movimientos preferidos en maxila y mandíbula para obtener normalidad en morfología facial utilizando técnicas de superimposición en análisis 3D. Se realizó un estudio descriptivo para evaluar el desplazamiento óseo bimaxilar y del hueso hioides en sujetos clase facial tipo II y clase facial tipo III sometidos a cirugía ortognática. Para la superimposición se utilizó como puntos fijos Nasion - Silla - Porion y la sutura cigomática-maxilar. Estos puntos se superpusieron en CBCT pre quirúrgico y postquirúrgico y se evaluó el desplazamiento de la espina nasal anterior, Punto A, Punto B, mentón y del hueso hioides. Para la evaluación y comparación de las variables continuas antes y después de la cirugía ortognática se utilizó la prueba T de Student. Para la correlación entre las variables, se utilizó el Test de Spearman considerando un valor p<0,05 como diferencia significativa. 44 sujetos de entre 18 y 40 años de ambos sexos, fueron incluidos en esta investigación. En el 90 % de los sujetos se realizó un movimiento sagital de avance de la maxila. El movimiento sagital de avance mandibular se realizó en el 100 % de los sujetos con clase facial tipo II, mientras que el 100 % de los sujetos con clase facial tipo III se realizó se le retroceso mandibular. El hueso hioides presentó un avance en 26 de los 27 sujetos con clase facial tipo III. Es posible concluir que existe una tendencia al avance maxilar independiente de la deformidad facial.

ABSTRACT: The objective of this research was to determine the preferred movements in the maxilla and mandible to obtain normality in facial morphology using superimposition techniques in 3D analysis. A descriptive study was carried out to evaluate bimaxillary bone displacement and hyoid bone in subjects facial class II and facial class III undergoing orthognathic surgery. were used as fixed points for superimposition: Nasion (N) - Silla (S) - Porion (Po) and the zygomatic-maxillary suture (Z). These points were superimposed in pre-surgical and post- surgical CBCT and was evaluated to displacement of the anterior nasal spine, Point A, Point B, Chin and the hyoid bone. For the evaluation and comparison of continuous variables before and after orthognathic surgery, was used the Student's t test. For the correlation between the variables, the Spearman test is used, considering a p value <0.05 as a significant difference. 44 subjects between 18 and 40 years old of both sexes were included in this research. A 90% of subjects a was performed a maxillay sagittal movement. The sagittal movement of mandibular advancement was performed in 100% with facial class type II, while 100 % of the subjects with with facial class type III had a mandibular recession. The hyoid bone advanced in 26 of the 27 subjects with facial class type II. It is possible to conclude that there is a tendency for maxillary advancement, independent of facial deformity.

Sex estimation from maxillary arch measurements in Egyptian populations: cross-sectional study / Estimación sexual a partir de mediciones del arco maxilar en poblaciones egipcias: estudio transversal

SUMMARY: Sex estimation is an essential step in personal identification and a cornerstone for developing biological profile from skeletal remains. The present study aimed to evaluate the role of maxillary arch widths and lengths as unique parameters in the estimation of sex in Egyptian populations. Maxillary arch measurements were collected from 1410 subjects where palatal impressions were obtained from each participant. Fourteen maxillary inter-teeth widths and lengths that excluded teeth dimensions were included The current study revealed that among the studied population, Egyptian men showed significant differences (p34.57 mm, it could predict the sex with sensitivity of 69.8 %, specificity of 58.8 % and p<0.05. The first molar could be considered as one of the most valid and reliable teeth in estimating sex in Egyptian populations. These measurements may be used as a reference in different populations in cases of mass disaster or relevant events.

RESUMEN: La estimación del sexo es un aspecto esencial en la identificación personal para desarrollar el perfil biológico a partir de restos óseos. El presente estudio tuvo como objetivo evaluar el papel del ancho y longitud del arco maxilar como parámetros únicos en la estimación del sexo en poblaciones egipcias. Se obtuvieron medidas del arco maxilar de 1410 sujetos, además de las impresiones palatinas de cada participante. El estudio actual reveló que entre la población estudiada, los hombres egipcios mostraron diferencias significativas (p 34,57 mm, podría predecir el sexo con sensibilidad de 69,8 %, especificidad de 58,8 % y p <0,05. El primer molar podría considerarse como uno de los dientes más confiables para estimar el sexo en las poblaciones egipcias. Estas mediciones se pueden utilizar como referencia en diferentes poblaciones en casos de desastres masivos o eventos relevantes.

Anatomical study of the canalis sinuosus in Chilean individuals by cone-beam computed tomography / Estudio anatómico del canal sinuoso en individuos chilenos mediante tomografía computarizada cone-beam

SUMMARY: The canalis sinuosus (CS) is a double-curved bone canal in the anterior region of the maxilla. The CS contains a vasculo-nervous bundle consisting of the anterior superior alveolar nerve and its corresponding arteries and veins. The CS and its accessory canals (AC) have been little described in the literature and are often omitted in imaging evaluations before procedures in the region. The object of the present study was to evaluate the frequency of the CS and its AC in Chilean individuals, and to carry out a morphometric analysis of these anatomical structures by cone-beam computed tomography (CBCT) by sex, side and age range. CBCT examinations of 28 patients were studied, evaluating the presence, diameter and terminal portion of the CS. We also evaluated the presence and number of AC, and their terminal portion. The diameter of the AC was classified as greater or smaller than 1.0 mm. Non-parametric tests were used for quantitative variables and chi-squared for qualitative variables. The SPSS v.27.0 software was used, with a significance threshold of 5 %. The CS was present in all the samples analysed, generally presenting a diameter greater than 1.0 mm. Alterations were found, and the diameter could be greater depending on the segment evaluated, however it was not affected by sex, side or age range. The terminal portion of the CS is usually located adjacent to the region of the nasal cavity. The frequency of AC was very high, and the most common location was in the region of the upper central incisor; in 61.3 % of cases their diameter ?1.0 mm. The high frequency of CS and AC shows the importance of carrying out a detailed imaging study before invasive procedures in the anterior region of the maxilla.

RESUMEN: El canal sinuoso (CS) es un canal óseo que presenta doble curvatura, ubicado en la región anterior de maxila. El CS contiene un paquete vásculonervioso formado por nervio alveolar superior anterior, arterias y venas correspondientes. El CS y sus canales accesorios (CA) han sido poco descritos en la literatura y muchas veces son omitidos en evaluaciones imagenológicas previas a procedimientos en la región. El objetivo del presente estudio fue evaluar la frecuencia del CS y de sus CA en individuos Chilenos, bien como realizar un análisis morfométrico de estas estructuras anatómicas mediante tomografía computarizada cone-beam (TCCB) según sexo, lado y rangos etarios. Fueron evaluados exámenes de TCCB de 28 pacientes. Se evaluó la presencia, diámetro y porción terminal del CS. Se evaluó la presencia del CA, cantidad y porción terminal. El diámetro del CA fue clasificado en mayor o menor a 1,0 mm. Se utilizaron pruebas no paramétricas para variables cuantitativas y chi-cuadrado para variables cualitativas. Se utilizó el software SPSS 27.0, considerándose umbral de significación de 5 %. El CS estuvo presente en todas las muestras analizadas, presentando en general un diámetro mayor a 1,0 mm. El diámetro del CS sufre alteraciones pudiendo ser mayor dependiendo de la región evaluada, sin embargo no se ve afectado por sexo, lado o rangos etarios. La porción terminal de CS suele ubicarse adyacente a la región de cavidad nasal. La frecuencia de CA es muy alta, en un 61,3 % presentan diámetro ?1,0 mm, siendo la región de incisivo central superior su ubicación más común. La alta frecuencia de CS y de CA demuestra la importancia de realizarse un detallado estudio imagenológico previo a procedimientos invasivos en región anterior de la maxila.

Root anatomy and canal configuration of maxillary premolars: a cone-beam computed tomography study / Anatomía de la raíz y configuración del conducto de los premolares maxilares: estudio de tomografía computarizada de haz cónico

SUMMARY: The aim of the study was to determine the number and anatomical configuration of roots and root canals of maxillary first and second premolars using cone-beam computed tomography scans. n273 CBCT scans were evaluated, obtaining a sample of 592 maxillary premolars. Root number and root canal anatomy were categorized using Ahmed´s classification. Data was analyzed using Pearson's Chi-squared test. Two roots were present on 157 first premolars, one root in 132 premolars and three roots in 17. Second premolars presented one root in 266 samples and two roots in 20; no second premolars presented three roots. Eight different configurations were found; the most frequent was 2MP B1 P1 in first premolars (51,3 %) and 1MP1 (63.6 %) in second premolars. The most frequent morphology found in maxillary premolars in Chilean population was two and three roots. The analysis of internal anatomy using CBCT revealed a highly variable distribution of root canals, generally of low to medium complexity, similar to what is found in other ethnic groups.

RESUMEN: El objetivo de este estudio fue determinar el número y la configuración de raíces y canales radiculares de primeros y segundos premolares maxilares utilizado tomografía computacional de haz cónico. 273 TCHC fueron evaluados, obtenido una muestra de 592 premolares maxilares. El número de raíces y la anatomía de los canales radiculares fueron categorizados utilizando la clasificación de Ahmed. Los datos fueron analizados con la prueba Chi- Cuadrado de Pearson. Dos raíces fueron observadas en 157 primeros presentaron una raíz en 266 muestras y dos raíces en 20; no se encontraron tres raíces en segundos premolares. Ocho diferentes configuraciones fueron encontradas; siendo la más frecuente 2MP B1 P1 en primeros premolares (51,3 %) y 1MP1 (63,6 %) en segundos premolares. La morfología radicular más frecuentemente encontrada en premolares de población Chilena fue de dos y tres raíces. El análisis de la anatomía interna usando TCHC mostró una gran variabilidad de en la distribución de los canales radiculares. Generalmente de mediana y baja complejidad como los encontrados en otros grupos etnicos.

Influence of the palatine tonsil grade on the morphology of the maxillary and mandibular dental arches / Influencia del grado de las tonsilas palatinas en la morfología de los arcos dentales maxilar y mandibular

SUMMARY: Enlarged palatine tonsils and adenoids are thought to cause obstruction of the upper airway, triggering changes in breathing patterns, which in turn lead to dentofacial alterations, including malocclusions. The object of the present study was to correlate the size (grade) of the palatine tonsil with measurements of the maxillary and mandibular dental arches in children. This was an observational cross-sectional study carried out in 35 children aged between 6 and 11 years. The inter- and intra-arch parameters were measured (horizontal, vertical and sagittal analyses) by making plastercasts and then taking measurements with callipers. The tonsil size was classified in 5 grades from 0-4, using the Brodsky tonsil grading scale. The researcher was calibrated prior to carrying out the measurements. Pearson's chi-squared test was used and Pearson's correlation coefficient was calculated. The SPSS v.22.0 software was used, with a significance threshold of 5 %. Six patients were classified as grade 1, sixteen grade 2, eleven grade 3, two grade 4 and none of the patients presented grade 0.A low positive association was found between tonsil grade and the total length of the mandibular arch, a very low positive association between tonsil grade and maxillary inter-first premolar distance, total length of the maxillary arch and depth of the palatine recess.A very low negative association was found for tonsil grade and overjet, overbite, mandibular inter-permanent first molar distance, mandibular inter-first premolar distance, and mandibular and maxillary intercanine widths. No statistically significant correlation was observed for any of the measurements. No association was found between the tonsil grade and Angle's Classification, canine relationship, overjet and overbite. According to the results of this study there is no significant correlation between the dental arches and the tonsil grade.

RESUMEN: Se ha considerado que el grado del tamaño de las tonsilas palatinas y los adenoides pueden ser factores que generan obstrucción de la vía aérea superior, desencadenando cambios en el patrón de respiración, lo que provoca alteraciones dentofaciales, entre ellas, maloclusiones. El objetivo del presente estudio fue correlacionar el grado tonsilar palatino con medidas de los arcos dentales maxilar y mandibular en niños. Se realizó un estudio observacional de corte transversal. Fueron incluidos 35 niños entre 6 y 11 años de edad. Fueron medidos parámetros interarco e intra-arco (análisis transversal, vertical, sagital). Para eso fueron tomados modelos de yeso y luego las medidas fueron realizadas con un caliper. El grado tonsilar fue clasificado en 5 grados (0-5), de acuerdo a la escala de graduación de Brodsky. Para la realización de las mediciones el evaluador fue previamente calibrado. Se realizó la prueba Chi-cuadrado de Pearson, y coefi- ciente de correlación de Pearson. Se utilizó el software SPSS 22.0, considerándose umbral de significación de 5 %. Seis pacientes fueron clasificados en grado 1, dieciséis grado 2, once grado 3, dos grado 4 y ningún paciente presentó grado 0. Se encontró una asociación positiva baja entre grado tonsilar y la longitud total del arco mandibular, positiva muy baja entre grado tonsilar y distancia inter-primer premolar maxilar, longitud total del arco maxilar y profundidad de la bóveda palatina. Una asociación negativa muy baja fue encontrada para el grado tonsilar y overjet, overbite, distancia inter-primer molar permanente mandibular, distancia inter- primer premolar mandibular, ancho intercanino mandibular y maxilar. Se observó ausencia de correlación estadísticamente significativa para todas las medidas. No se encontró asociación entre el grado tonsilar y clase molar de Angle, relación canina, overjet y overbite. Según los resultados de este estudio no se aprecia una correlación significativa entre los arcos dentales y el grado tonsilar.

Morphological analysis of maxillary first premolars by cone beam computed tomography in a Chilean sub-population / Análisis morfológico de primeros premolares maxilares a través de tomografía computarizada de haz cónico en una subpoblación chilena

SUMMARY: The root canal system of the maxillary first premolar (MFP), present a high rate of variation, especially at apical level. This complicates the action of antiseptic solutions and endodontic instruments at this level. The object of this in vivo study was to analyse by Cone Beam Computed Tomography (CBCT) the radicular and canalicular morphology of MFP in a Chilean sub-population. We carried out a cross sectional, descriptive and observational in vivo study with CBCT examinations of 70 MFP, both left and right. The data were analysed using descriptive statistics (mean (M), standard deviation (SD), with a confidence interval of 95 %), and one-factor ANOVA was used to relate the sections observed. Tooth 1.4 presented one root in 64.86 % of cases and two roots in 35.15 %. Tooth 2.4 presented one root in 66.67 % of cases and two roots in 33.33 %. The frequency of one and two canals was observed to be 30 % and 70% respectively. The walls with the smallest cementodentinal thickness were the mesial (1.11±0.55) and distal (1.08±0.52). The thickest dentinal wall was the palatine (2.07±1.29), followed by the buccal (1.6±1.0). No statistical differences between males and females were found in the thickness of the root wall, nor in the location of the premolar in the maxilla (p>0.05). In conclusion, the root morphology of the MFP is highly variable. Care must be taken not to over-instrument the proximal walls to avoid perforations or fractures. CBCT has proved to be a useful and effective diagnostic tool for in vivo study of dental morphology.

RESUMEN: El sistema de canal radicular del primer premolar maxilar (MFP) presenta una alta tasa de variación, especialmente a nivel apical. Esto complica la acción de las soluciones antisépticas y los instrumentos endodónticos a este nivel. El objetivo de este estudio in vivo fue analizar mediante tomografía computarizada de haz cónico (CBCT) la morfología radicular y canalicular de la MFP en una subpoblación chilena. Realizamos un estudio transversal, descriptivo y observacional in vivo con exámenes CBCT de 70 MFP, tanto a la izquierda como a la derecha. Los datos se analizaron mediante estadística descriptiva (media (M), desviación estándar (DE), con un intervalo de confianza del 95 %) y se utilizó ANOVA de un factor para relacionar las secciones observadas. El diente 1.4 presentó una raíz en el 64,86% de los casos y dos raíces en el 35,15 %. El diente 2.4 presentó una raíz en el 66,67 % de los casos y dos raíces en el 33,33 %. Se observó que la frecuencia de uno y dos canales era del 30 % y 70%, respectivamente. Las paredes con el espesor cementodentinal más pequeño fueron mesial (1,11 ± 0,55) y distal (1,08 ± 0,52). La pared dentinaria más gruesa fue la palatina (2,07 ± 1,29), seguida de la vestibular (1,6 ± 1,0). No se encontraron diferencias estadísticas entre machos y hembras en el grosor de la pared de la raíz, ni en la ubicación del premolar en el maxilar (p> 0,05). En conclusión, la morfología de la raíz de la MFP es muy variable. Se debe tener cuidado de no sobre-instrumentar las paredes proximales para evitar perforaciones o fracturas. CBCT ha demostrado ser una herramienta de diagnóstico útil y efectiva para el estudio in vivo de la morfología dental.

Prediction of the mesiodistal width of maxillary anterior teeth from nasal interalar width in peruvian subjects with facial harmony

Objective: To determine regression models to predict the mesiodistal widths of the maxillary anterior teeth from interalar width of the nose in subjects with facial harmony. Materials and Methods: A cross-sectional study was carried out in a sample of 75 subjects with facial harmony and ages ranging from 18 to 30 years (21.28±3.75 years). The mesiodistal width of the central (CI), lateral (LI) incisors, and canines (C), as well as the interalar width (IW) of each subject were measured using a digital vernier caliper. Simple linear regression analyses were used to predict the width of the maxillary anterior teeth from the nasal interalar width, from which formulas for predicting the dimensions of each anterior tooth were obtained. Results: A statistically significant relationship was found between the nasal interalar width and the mesiodistal widths of the upper central incisor (p=0.019, R2=5.23%), upper lateral incisor (p=0.019, R2=2.31%), and upper canine (p=0.016, R2=12.04%) that allowed to develop simple linear prediction models for each tooth represented by the following formulas: CI=7.04+0.04(IW); LI=6.01+0.03 (IW); C=6.19+0.05 (IW). Conclusion: The nasal interalar width is a good predictor of the mesiodistal widths of the maxillary anterior teeth.

Objectivo: Determinar modelos de regresión para predecir los anchos mesiodistales de los dientes anterosuperiores a partir del ancho interalar de la nariz en individuos con armonía facial. Materiales and Métodos: Se realizó un estudio transversal con una muestra de 75 sujetos con armonía facial entre 18 a 30 años (21.28 ± 3.75 años), se midió el ancho mesiodistal de incisivos centrales (IC), laterales (IL) y caninos (C) así como el ancho interalar (AI) de cada sujeto empleando un calibrador vernier digital. Para la predicción del ancho de los dientes anterosuperiores a partir del ancho interalar nasal se emplearon análisis de regresión lineal simple, a partir de los cuales se obtuvieron fórmulas de predicción de las dimensiones de cada pieza dentaria anterior. Resultados: Se encontró relación estadísticamente significativa entre el ancho interalar nasal y los anchos mesiodistales del incisivo central superior (p=0.019, R2 5.23%), incisivo lateral superior (=0.019, R2=2.31%) y canino superior (p=0.016, R2=12.04%) que permitieron generar modelos de predicción lineal simple para cada pieza dentaria representados mediante las siguientes fórmulas: IC=7.04+0.04(AI); IL=6.01+0.03(AI); C=6.19+0.05(AI). Conclusión:El ancho interalar nasal es un buen predictor de los anchos mesiodistales de los dientes anterosuperiores.

Esthetic proportions of maxillary anterior teeth of 120 Chinese adults / 北京大学学报(医学版)

OBJECTIVE@#To analyze the esthetic proportions of maxillary anterior teeth in term of the apparent widths proportion of the adjacent teeth and width/height ratio of the clinical crown in 120 Chinese adults.@*METHODS@#Maxillary gypsum casts were obtained from the dental laboratories of stomatological hospitals in North China, Southeast China, and Southwest China, according to the inclusion criteria and exclusion criteria. Standardized digital photographs of each cast were recorded. The apparent widths and actual widths and heights of the central incisors, lateral incisors and canines were determined by ImageJ software for the calculation of apparent widths proportion of the adjacent teeth and width/height ratio of the clinical crown. The ideal apparent widths proportion (Golden proportion and Preston proportion) and width/height ratio (0.80) were tested. The gender, arch side, and regional differences were investigated.@*RESULTS@#The apparent widths proportion of the lateral/central incisor was 0.724±0.047, of the canine/lateral incisor was 0.814±0.092. The width/height ratio of the central incisor was 0.848±0.072, of the lateral incisor was 0.834±0.094, of the canine was 0.883±0.098. The esthetic proportions were different from the predicted ideal ratio (P < 0.001). The apparent widths proportion of lateral/central incisor was significantly larger in the right side than that in the left side (0.730± 0.044 vs. 0.718±0.050), and was significantly smaller in North China than that in Southwest China (0.711±0.051 vs. 0.731±0.044). The width/height ratio of the central incisor was significantly larger in the female than that in the male (0.855±0.074 vs. 0.835±0.068), and in the right side than that in the left side (0.855±0.073 vs. 0.842±0.072). The width/height ratio of the lateral incisor was significantly larger in the female than that in the male (0.843±0.097 vs. 0.817±0.084).@*CONCLUSION@#The apparent widths proportion of adjacent teeth and the width/height ratio of the clinical crown in Chinese adults are different from the foreigner's. The esthetic proportion parameters have significant population specificity, and the measurements cannot be generalized as well as it should be applied with caution.

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.

Micro-computed tomographic assessment of the variability and morphological features of root canal system and their ramifications

Abstract Objectives This study assessed the incidence and variability features of root canals system (RCS) and their ramifications according to Pucci & Reig (PR) (1944) and the American Association of Endodontists (AAE) (2017) by micro-computed tomography (μCT). Methodology 500 representative extracted human teeth of each tooth group (n=50) (maxillary/mandibular central and lateral incisors, canines, first and second premolars and molars) were scanned by μCT with a resolution of 26.70 μm. The reconstructed cross-sections images and the visualization of the continuous slices in the transversal axis were performed using DataViewer software. RCS were classified according to Pucci & Reig (main canal, collateral canal, lateral canal, secondary canal, accessory canal, intercanal, recurrent canal) and AAE (main canal, accessory canal, lateral canal). The apical deltas were assessed for both classifications. The prevalence of apical deltas was evaluated using the Chi-squared test (p<0.05). Results According to PR, a higher incidence of lateral canals was observed in maxillary canines (10%), central incisors (8%) and first premolars (6%). Using AAE, the highest incidence of lateral canals was observed in the mandibular first premolars (85%), first and second molars (84%), lateral incisors (67%), canines (59%), and in maxillary first premolars (52%). Regarding accessory canals, the PR showed a frequency in 2% of the maxillary lateral incisors and maxillary and mandibular first premolars and 3% of mandibular first and second molars. On the other hand, the AAE showed the highest incidence of accessory canals in 86% of the maxillary first premolars, 71% in mandibular lateral incisors, 69% in mandibular first premolars, 65% in mandibular canines, and 56% in maxillary canines. The PR showed the lowest incidence of apical deltas for all dental groups when compared with AAE (p=0.004). Interestingly, distal canals in maxillary molars showed a significant discrepancy between classifications (p=0.027). Conclusions μCT enabled accurately describing the RC system and related ramifications, adding to the PR and AAE classifications, with some discrepancies reported for maxillary molars. Clinical Relevance This μCT study enabled a thorough description of the variability among root canals and their ramifications, including clinically relevant details on the presence and location of lateral canals and accessories in all human tooth groups, beyond the currently existing classification systems.

Correlation between the cephalometric measurements and acoustic properties of /s/ sound in Turkish

Abstract Objectives To evaluate the acoustic properties of the /s/ sound in individuals with different occlusion types and to investigate relationships between these properties and cephalometric measurements. Methodology Sixty patients were divided into three groups based on malocclusion. Group 1 included 20 patients (mean age: 14.85±2.01 years) with Class I skeletal and dental relationships. Group 2 included 20 patients (mean age: 13.49±1.78 years) with Class II skeletal and dental relationships. Group 3 included 20 patients (mean age: 12.46±2.62 years) with Class III skeletal and dental relationships. Cephalometric tracings were obtained from cephalometric radiographs. All included patients were native speakers of Turkish. The /s/ sound was selected for center of gravity analysis. Correlations between cephalometric values and acoustic parameters were also investigated. Results The center of gravity of the /s/ sound had the lowest value in Group 2 (p<0.05). For the /s/ sound in Group 3, moderate positive correlations were found between center of gravity and Sella-Nasion to Gonion-Gnathion angle (p<0.05, r=0.444) Lower incisor to Nasion-B point (p<0.023, r=0.505), and Lower incisor to Nasion-B point angle (p<0.034; r=0.476). No correlation was found in other cephalometric measurements. Conclusions The /s/ sound was affected by malocclusion due to the changing place of articulation. Therefore, referral to an orthodontist for malocclusion treatment especially patients with class III in the early period is suggested for producing acoustically ideal sound.

Contribución al Estudio Descriptivo del Foramen y Canal Palatino Mayor / Contribution to the Descriptive Study of the Foramen and Greater Palatine Canal

RESUMEN: El foramen y canal palatino mayor (FPM y CPM) comunican boca con fosa pterigopalatina. El conocimiento adecuado de su morfología, permite el abordaje anestésico del nervio maxilar. En el vivo, el FPM está recubierto por una mucosa gruesa, debido a esto los puntos de referencia óseos y dentarios son importantes para ubicar el sitio de punción. Se ha descrito gran variabilidad en cuanto a la etnia, posición, forma, diámetros, longitudes y permeabilidad. Este estudio tuvo como objetivo describir éstas características en cráneos de adultos chilenos. Se utilizaron 31 cráneos de ambos sexos. En los paladares se determinó; forma, largo, profundidad y ancho. En los FPM se consideró su forma, diámetros y localización. En los CPM se registró su permeabilidad y su coincidencia con la forma del FPM. Los registros se realizaron con cámara digital, compás de precisión, caliper digital, compas tridimensional de Korkhaus y sonda metálica. Los resultados muestran un predominio de la forma cuadrada del paladar por sobre las formas triangular y redondeada. Las mediciones de su largo, ancho y profundidad indican diferencias por sexo y por etnia. La forma del FPM no muestra diferencia por sexo, primando la forma ovalada por sobre la fusiforme y la redondeada. La posición de este mismo foramen tampoco muestra diferencias sexuales, primando la posición frente al tercer molar superior, seguida por la posición frente al espacio entre segundo y tercer molar superior y por último frente al 2do molar superior. Las dimensiones del FPM son mayores en individuos masculinos. Los CPM se observaron en su totalidad permeables y los FPM no siempre coincidieron en forma con la sección transversal del CPM. Estos resultados y su comparación con la literatura indican variaciones importantes, lo que impide establecer directrices objetivas a la técnica anestésica que utiliza esta vía anatómica.

ABSTRACT: The greater palatine foramen and canal (GPF and GPC) communicate with the pterygopalatine fossa. The adequate knowledge of its morphology allows the anesthetic approach of the maxillary nerve. In vivo, the GPF is covered by a thick mucosa, therefore, the bone and dental reference points are important to locate the puncture site. Great variability has been described in terms of ethnicity, position, shape, diameters, lengths and permeability. The objective of this study was to describe these characteristics in skulls of Chilean adults. 31 skulls of both sexes were used. In the palates shape, length, depth and width were determined. In the GPF its shape, diameters and location were considered. In the GPC, their permeability and their coincidence with the shape of the GPF were recorded. The records were made with digital camera, precision compass, digital caliper, Korkhaus three-dimensional compass and metallic probe. The results show a predominance of the square shape of the palate over the triangular and rounded forms. The measurements of its length, width and depth indicate differences by sex and ethnicity. The shape of the GPF shows no difference by sex, with the oval shape prevailing over the fusiform and the rounded. The position of this same foramen also shows no sexual differences, with the position prevailing against the upper third molar, followed by the position in front of the space between the upper second and third molars and finally against the upper 2-molar. The dimensions of GPF are greater in male individuals. The GPC were found to be entirely permeable and the GPF did not always coincide in form with the cross section of the GPC. These results and their comparison with the literature indicate important variations, which prevents establishing objective guidelines for the anesthetic technique used in these cases.

Premaxilla: up to which age it remains separated from the maxilla by a suture, how often it occurs in children and adults, and possible clinical and therapeutic implications: Study of 1,138 human skulls

ABSTRACT Objective: To evaluate topographic and temporal aspects of premaxillary bone and premaxillary-maxillary suture, since they are fundamental anatomical elements little explored clinically. Methods: 1,138 human dry skulls were evaluated, of which 116 (10.19%) of the specimens were children, and 1,022 (89.81%) were adults. The skulls were photographed and the percentage of premaxillary-maxillary suture opening was determined. Subsequently the data were tabulated and submitted to statistical analysis, adopting a level of significance of 5%. Results: The progression of premaxillary suture closure from birth to 12 years of age was 3.72% per year. In 100% of the skulls up to 12 years, the premaxillary-maxillary suture open in the palatal region was observed, while 6.16% of adults presented different degrees of opening. Conclusions: The premaxilla exists in an independent way within the maxillary complex and the presence of the premaxilla-maxillary suture justifies the success of anteroposterior expansions to stimulate the growth of the middle third of the face, solving anatomical and functional problems.

RESUMO Objetivo: avaliar aspectos topográficos e temporais do osso pré-maxilar e da sutura pré-maxilar/maxilar, por serem elementos anatômicos fundamentais pouco explorados clinicamente. Métodos: foram avaliados 1.138 crânios secos humanos, sendo 116 (10,19%) dos espécimes crianças e 1.022 (89,81%) adultos. Os crânios foram fotografados e determinou-se a porcentagem de abertura da sutura pré-maxilar/maxilar. Posteriormente, os dados foram tabulados e submetidos a análise estatística, adotando-se nível de significância de 5%. Resultados: a progressão de fechamento da sutura pré-maxilar/maxilar do nascimento aos 12 anos de idade foi de 3,72% ao ano. Em 100% dos crânios até 12 anos, observou-se a sutura pré-maxilar/maxilar aberta na região palatina, enquanto 6,16% dos adultos apresentavam diferentes graus. Conclusões: a pré-maxila existe de forma independente dentro do complexo maxilar e a presença da sutura pré-maxilar / maxilar justifica o sucesso de expansões anteroposteriores para estimular o crescimento do terço médio da face, solucionando problemas anatômicos e funcionais.

The maxillary incisor display at rest: analysis of the underlying components

ABSTRACT Introduction: Maxillary incisal display is one of the most important attributes of smile esthetics. Objective: The aim of this study was to determine the relationship between maxillary incisal display at rest (MIDR) and various soft tissue, hard tissue and dental components. Methods: A cross-sectional study was conducted on 150 subjects (75 males, 75 females) aged 18-30 years. The MIDR was recorded from the pretreatment orthodontic records. The following parameters were assessed on lateral cephalograms: ANB angle, mandibular plane angle, palatal plane angle, lower anterior and total anterior facial heights, upper incisor inclination, upper anterior dentoalveolar height, and upper lip length, thickness and protrusion. The relationship between MIDR and various skeletal, dental and soft tissue components was assessed using linear regression analyses. Results: The mean MIDR was significantly greater in females than males (p = 0.011). A significant positive correlation was found between MIDR and ANB angle, mandibular plane angle and lower anterior facial height. A significant negative correlation was found between MIDR and upper lip length and thickness. Linear regression analysis showed that upper lip length was the strongest predictor of MIDR, explaining 29.7% of variance in MIDR. A multiple linear regression model based on mandibular plane angle, lower anterior facial height, upper lip length and upper lip thickness explained about 63.4% of variance in MIDR. Conclusions: Incisal display at rest was generally greater in females than males. Multiple factors play a role in determining MIDR, nevertheless upper lip length was found to be the strongest predictor of variations in MIDR.

RESUMO Introdução: a exposição dos incisivos superiores é um dos fatores mais importantes na estética do sorriso. Objetivo: o objetivo desse estudo foi determinar a relação entre a exposição dos incisivos superiores em repouso (EISR) e diferentes componentes em tecidos moles, tecidos duros e dentários. Métodos: um estudo transversal foi conduzido com 150 pacientes (75 homens, 75 mulheres), com idades entre 18 e 30 anos. A EISR foi obtida nos registros pré-tratamento ortodôntico. Os seguintes parâmetros foram analisados nas radiografias laterais: ângulo ANB; ângulo do plano mandibular; ângulo do plano palatino; altura facial anterior inferior; altura facial anterior total; inclinação dos incisivos superiores; altura dentoalveolar anterior superior; comprimento, espessura e protrusão do lábio superior. A relação entre a EISR e os diferentes componentes esqueléticos, dentários e em tecidos moles foi analisada por meio de uma análise de regressão linear. Resultados: a EISR média foi significativamente maior nas mulheres do que nos homens (p= 0,011). Foi encontrada correlação positiva significativa entre a EISR e: o ângulo ANB, ângulo do plano mandibular e a altura facial anterior inferior. Uma correlação negativa significativa foi encontrada entre a EISR e o comprimento e a espessura do lábio superior. A análise de regressão linear mostrou que o comprimento do lábio superior foi o maior preditor da EISR, explicando 29,7% das variações na exposição dos incisivos superiores em repouso. Um modelo de regressão linear múltipla baseado no ângulo do plano mandibular, na altura facial anterior inferior, comprimento do lábio superior e espessura do lábio superior explicou cerca de 63,4% das variações na EISR. Conclusões: a exposição dos incisivos em repouso foi, de um modo geral, maior nas mulheres do que nos homens. Múltiplos fatores exercem influência na quantidade da exposição dos incisivos superiores em repouso; porém, o comprimento do lábio superior foi identificado como o maior preditor das variações na EISR.

Correlation between craniofacial growth and upper and lower body heights in subjects with Class I occlusion

ABSTRACT Objective: To correlate skeletal age, standing height, upper and lower body lengths, and selected craniofacial growth features in a sample of growing individuals, and to model craniofacial growth using multivariate regression. Methods: This was a retrospective cross-sectional study with 447 African black boys and girls, between the ages 8 and 16 years, who attended the dental clinic at one hospital. The skeletal maturational age was determined from hand-wrist radiographs using the Greulich and Pyle atlas. Craniofacial measurements representing maxillary length (Ar-ANS), mandibular length (Ar-Gn), and lower facial height (ANS-Me) were calculated from lateral cephalograms in habitual occlusion. Body lengths were clinically measured in centimeters. Results: Moderate correlations (r=0.42 to 0.68) were observed between skeletal age and the three selected craniofacial measurements. Statistically significant correlations were also found between the craniofacial measurements and both upper and lower body lengths. The mandibular length had a stronger correlation with the upper body length than with the lower body length. Multiple regression analyses to determine maxillary and mandibular lengths suggested that sex, upper and lower body lengths might be used to determine maxillary length; while skeletal age, upper and lower body lengths might help determine mandibular length. Conclusions: Based on the relatively strong correlation between upper body length and mandibular length, further research in this area may warrant its use as a predictor for mandibular growth modification timing.

RESUMO Objetivo: correlacionar a idade esquelética, a estatura, as alturas corporais superior e inferior, e algumas características específicas do crescimento craniofacial, em uma amostra de indivíduos em crescimento, e delinear o crescimento craniofacial usando regressão multivariada. Métodos: esse estudo transversal retrospectivo foi feito com 447 meninos e meninas negros africanos, com idades entre 8 e 16 anos, atendidos na clínica odontológica de um hospital. A maturação esquelética, em anos, foi determinada a partir de radiografias de mão e punho, usando o atlas de Greulich e Pyle. As medidas craniofaciais representando o comprimento maxilar (Ar-ENA), o comprimento mandibular (Ar-Gn) e a altura facial anterior inferior (ENA-Me) foram calculadas a partir de cefalogramas laterais em oclusão habitual. Os comprimentos corporais foram medidos clinicamente, em centímetros. Resultados: correlações moderadas (r = 0,42 a 0,68) foram observadas entre a idade esquelética e as três medidas craniofaciais selecionadas. Também foram encontradas correlações estatisticamente significativas entre as medidas craniofaciais e as alturas corporais superior e inferior. O comprimento mandibular teve uma correlação mais forte com a altura corporal superior do que com a inferior. As análises de regressão múltipla para determinar os comprimentos maxilar e mandibular sugeriram que o sexo e as alturas corporais superior e inferior podem ser usados para determinar o comprimento maxilar, enquanto a idade esquelética e as alturas corporais superior e inferior podem ajudar a determinar o comprimento mandibular. Conclusões: com base na correlação relativamente forte entre a altura corporal superior e comprimento mandibular, pesquisas adicionais nessa área poderiam justificar seu uso como indicador para o período de modificação do crescimento mandibular.

Segmentation methods for micro ct images: a comparative study using human bone samples

Abstract X-ray microtomography (microCT) is a nondestructive technique used to assess bone morphometry. For an accurate analysis, it is necessary to segment the bone tissue from the background images, avoiding under- or overestimation of the real bone volume. Thus, segmentation methods for microCT can influence the accuracy of bone morphometry analysis. The purpose of this study was to compare two different image segmentation methods available on microCT software (subjective and objective) regarding to the human bone morphometric analysis. Sixteen samples containing a fixation screws covered by 0.5-1mm of bone were scanned using the SkyScan 1173 scanner. Three examiners segmented the microCT images subjectively and recorded the threshold values. Subsequently, an objective segmentation was also done. The 3D analysis was performed for both images using the values​ previously determined in CTAn software. Five bone morphometric parameters were calculated (BV/TV, Tb.Th, Tb.N, Tb.Sp, Conn.Den) and used as dependent variables. ANOVA showed no significant differences between the methods concerning BV/TV (p=0.424), Tb.N (p=0.672), Tb.Th (p=0.183), Tb.Sp (p=0.973) and Conn.Den (p=0.204). Intra- and interobserver agreement ranged from satisfactory to excellent (0.55-1 and 0.546-0.991, respectively). Therefore, results obtained with subjective threshorlding were similar to those obtained with objective segmentation. Since objective segmentation does not have human input and it is a truly objective method, it should be the first choice in microCT studies that concern homogeneity and high resolution human bone sample.

Resumo A microtomografia computadorizada (microTC) é uma modalidade de imagem não destrutiva utilizada para avaliar a morfometria óssea. Para análise acurada, faz-se necessário segmentar o tecido ósseo do fundo (background) da imagem, evitando assim, sub ou sobre estimação do volume ósseo real. Desta forma, fica evidente que os métodos de segmentação em análise de microTC podem influenciar a precisão dos cálculos da morfometria óssea. A realização do presente estudo teve como objetivo comparar o desempenho de dois diferentes métodos de segmentação de imagem de microTC, subjetivo e objetivo, através da avaliação dos resultados das análises morfométricas obtidas de ossos humanos. Dezesseis amostras contendo parafusos de fixação cobertos por 0,5- 1 mm de osso humano foram escaneados usando o microtomógrafo SkyScan1173. Três examinadores realizaram a segmentação das imagens de forma subjetiva (visualmente) obtendo seus respectivos valores de threshold. Em seguida, a segmentação objetiva (automática) foi realizada. As análises tridimensionais foram obtidas utilizando os valores determinados por ambos os métodos no software CTAn. Cinco parâmetros morfométricos do osso foram calculados (BV / TV, Tb.Th, Tb.N, Tb.Sp, Conn.Den) e usados ​​como variáveis ​​dependentes. O teste ANOVA não mostrou diferenças estatisticamente significantes entre os métodos comparados: BV / TV (p=0,424), Tb.N (p=0,672), Tb.Th (p=0,183), Tb.Sp (p=0 973) e Conn.den (p=0,204). A concordância intra e interobservardores variou entre satisfatória e excelente (0,55-1 e 0,546-0,991, respectivamente). Portanto, os resultados obtidos com a segmentação subjetiva foram semelhantes aos obtidos com a automática. Entretanto, a segmentação automática dispensa intervenção humana, sendo um método verdadeiramente objetivo e deve ser a primeira escolha em estudos microTC que objetivam avaliar a morfometria óssea humana.