Second mesiobuccal canal segmentation with YOLOv5 architecture using cone beam computed tomography images.

The objective of this study is to use a deep-learning model based on CNN architecture to detect the second mesiobuccal (MB2) canals, which are seen as a variation in maxillary molars root canals. In the current study, 922 axial sections from 153 patients' cone beam computed tomography (CBCT) images were used. The segmentation method was employed to identify the MB2 canals in maxillary molars that had not previously had endodontic treatment. Labeled images were divided into training (80%), validation (10%) and testing (10%) groups. The artificial intelligence (AI) model was trained using the You Only Look Once v5 (YOLOv5x) architecture with 500 epochs and a learning rate of 0.01. Confusion matrix and receiver-operating characteristic (ROC) analysis were used in the statistical evaluation of the results. The sensitivity of the MB2 canal segmentation model was 0.92, the precision was 0.83, and the F1 score value was 0.87. The area under the curve (AUC) in the ROC graph of the model was 0.84. The mAP value at 0.5 inter-over union (IoU) was found as 0.88. The deep-learning algorithm used showed a high success in the detection of the MB2 canal. The success of the endodontic treatment can be increased and clinicians' time can be preserved using the newly created artificial intelligence-based models to identify variations in root canal anatomy before the treatment.

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.

Radiological examination of the relationship between the pterygomaxillary junction and fracture pattern.

BACKGROUND: Le Fort 1 (LF1) osteotomies are widely used to correct midface deformities. To move the maxilla freely, the ptery-gomaxillary junction (PMJ) must be separated. When performing this osteotomy, the pterygoid plate must remain intact. The objective of this study was to evaluate relationship between the anatomical features of the PMJ and fracture patterns in LF1 osteotomy. METHODS: Pre-operative and post-operative cone-beam computed tomography images of 41 patients (82 samples) who have undergone LF1 osteotomy surgery were radiologically evaluated. Morphologic measurements of the pterygomaxillary fissure area and pterygoid plate were carried out. Moreover, pterygomaxillary separation was divided into the clean-cut, maxillary sinus, and pterygoid plate fracture types. RESULTS: Statistically significant difference was observed between clean-type fracture and pterygoid plate fracture groups' thickness of the pterygoid process and thickness of the pterygomaxillary region. CONCLUSION: Anatomical variations make it difficult to separate the PMJ properly. Low thickness of PMJ increases the risk of unwanted fractures; however, according to our experience, the use of an osteotome with an incorrect angle, excessive force, and inexperienced surgeons can also cause undesirable pterygoid plate fractures.

Evaluation of the morphology of accessory canals of the canalis sinuosus via cone-beam computed tomography.

PURPOSE: This study aims to assess the presence of accessory canal (AC) associated with canalis sinuous (CS), describing their frequency, lateralization, location, direction, and measurements in cone beam computed tomography (CBCT). METHODS: Axial, coronal, sagittal, and cross-sectional reconstructions were analyzed in 248 CBCT images and the presence of CS, the presence of AC associated with CS, the lateralization, localization, and direction course of AC associated with CS was evaluated. CS diameter, AC diameter, the distance between the nasal cavity floor and CS (M1), CS and the buccal cortical bone (M2), and CS and the alveolar ridge (M3) were measured. RESULTS: CS was detected in all CBCT scans as bilaterally. The prevalence of AC associated with CS was 35.5%. There was a significant difference between dental status anthe d presence of AC associated with CS. There was a significant difference between gender, dental status, and lateralization of AC associated with CS. While M1 was greater in male patients than females, M3 was greater in female patients. M2 and M3 were greater in younger patients. CONCLUSION: Clinicians performing surgical procedures should keep in mind that anatomical variations of the vascular nerve bundle may be seen. M1, M2, and M3 measurements can be affected by gender, age, and dental status.

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.

Age-Dependent Three-Dimensional Evaluation of Circummaxillary Sutures Maturation in Normal Population Using Cone-Beam Computed Tomography: Early Childhood Through Adolescence.

INTRODUCTION: Initiation time of dentofacial orthopedics is as important as the choice of treatment protocol. Morphology and degree of fusion of circummaxillary sutures differ in various populations; hence, the aim of this study was to evaluate the exact age of ossification of the most important maxillary suture using cone-beam computed tomography to find the appropriate age to start orthopedic treatment. METHODS AND MATERIALS: This cross-sectional retrospective study was performed on 517 cone-beam computed tomography images of patients aged 6 to 18 years old. Patients with obvious pathology or fractures were excluded from the study. Two independent observers scored the radiographs. The ossification stage of the zygomatico-maxillary suture (ZMS) was classified into 5 stages and each suture was classified according to age and sex of the patients. Kendall Taub, Kruskal-Wallis, Mann-Whitney U test, and Bayesian analysis were used for statistical analysis. Statistical significance was set at P value < 0.05. RESULTS: In this study, 517 samples consisting of 260 females (50.3%) and 257 males (49.7%) with a mean age of 12.03 ± 3.74 years old were examined. A significant difference did not exist between the 2 sexes regarding the stages of ZMS ossification except for in stage E. The ZMS transitional stage from B to C was found to occur at the age of 11.8 in boys and 12.6 in girls. CONCLUSIONS: According to the transitional age of ZMS maturation from stage B to C, it seems that orthopedic treatments of the maxilla are not much effective after the age of 12. Therefore, the authors should start orthopedic treatment of the maxilla before the age of 12 in both sexes.

Orbital and Periorbital Dysmorphology in Untreated Pfeiffer Syndrome.

BACKGROUND: Visual impairment secondary to orbital and periorbital dysmorphology is frequent in Pfeiffer syndrome patients. The etiopathogenesis of this aberrancy, however, remains unclear. METHODS: Untreated Pfeiffer syndrome patients (n = 31) and normal control subjects (n = 43) were compared. Craniometric and volumetric analyses related to the orbital and periorbital anatomy were performed using Materialise (Leuven, Belgium) software. RESULTS: Overall, orbital cavity volume of Pfeiffer patients is reduced by 28 percent (p < 0.001), compared to normal, starting before 3 months of age (p = 0.004). Globe volume was diminished by 10 percent (p = 0.041) before 3 months of age, yet tended to catch up thereafter. However, the retrobulbar soft-tissue volume remained smaller beyond 1 year of age (17 percent, p = 0.003). Globe volume projection beyond the bony orbit increased in all observed ages (82 percent, p < 0.001). The volumes of sphenoid bone, maxilla, and mandible proportionately were restricted by 24 to 25 percent (p = 0.003 to 0.035) before 3 months of age. The volume of maxilla and mandible gradually approximate normal; however, the sphenoid bone volume in Pfeiffer patients remains less than normal (p = 0.002) into childhood. The anteroposterior length of both the zygoma and the maxilla was reduced by 14 percent (p < 0.001). Anterior positioning of the zygoma is less by 23 percent (p < 0.001) in Pfeiffer patients overall, with anterior positioning of maxilla reduced similarly by 23 percent (p < 0.001). CONCLUSIONS: Pfeiffer syndrome patients develop decreased retrobulbar soft-tissue and globe volume, along with a restricted orbital cavity volume in infancy. Significant hypoplasia of the sphenoid bone is associated with more severe central facial (maxilla) retrusion, compared to lateral facial structures (zygoma). CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, II.

Complications According to the Handling of the Pterygoid Plate During Bimaxillary Surgery.

BACKGROUND: During bimaxillary surgery, manipulation of the pterygoid plate is required to facilitate movement of the maxilla. This study examined the complications that occurred after handling the pterygoid plate during a Le Fort I osteotomy. PATIENTS AND METHODS: This study compared and analyzed complications according to the pterygoid plate handling method in 80 patients who underwent bimaxillary surgery at Pusan National University Dental Hospital from December 2015 to July 2020. The pterygoid plate was fractured or removed intentionally only if it interfered with the maxilla. Otherwise, it was not treated. The complications during surgery and the follow-up period were investigated. RESULTS: Fourteen patients experienced complications, of which excessive bleeding, hearing problems, and nonunion were encountered in 10, 2, and 2 patients, respectively. Of the 10 patients with excessive bleeding patients, the pterygoid plate was manipulated in 8 patients, which was controlled during surgery. Two patients complained of hearing loss with ear congestion immediately after surgery; both patients improved spontaneously within 1 month. Two nonunion patients underwent plate refixation at least 6 months postoperatively, and normal healing was achieved afterward. CONCLUSIONS: Fracture and removal of the pterygoid plate during orthognathic surgery did not significantly affect the occurrence of complications during and after surgery.

Radioanatomic study of maxillary sinus palatal process pneumatization.

OBJECTIVES: To perform a detailed analysis of palatal process pneumatization (PPP) on cone beam computed tomography (CBCT) images. METHODS: This study consisted of 376 maxillary sinuses of 188 patients aged 22-88 years who had maxillary CBCT scans. The radioanatomy of the PPP was evaluated at distances 4, 8, 16, and 24 mm posterior to incisive foramen. The types of PPP were classified as follows: type I: maxillary sinus palatal process non-gasified; type II: palatal process gasification into the nasal floor, but not more than half of the width of the nasal floor; and type III: palatal process gasification into the nasal floor more than half of the width of nasal floor. Sinus opening angle (SOA), palatonasal recess angle (PNRA), palatal junction angle (PJA), and palatal depth measurement (PDM) were the evaluated parameters. RESULTS: Among the identified 1315 PPPs, type I PPP (880, 66.92%) was the most frequently observed, followed by type II (426, 32.4%), and the least observed was type III PPP (9, 0.68%). There was no significant difference between SOA and PJA according to the types of PPP (p > 0.05). The difference between PNRA and PDM of type I and type II PPP showed a statistically significant difference (p < 0.05). Type I PPP was the most encountered with the highest PDM, and PNRA was narrower in type III than in type II PPP. CONCLUSION: Physicians must be aware of these variations to prevent possible complications during surgery because 33.08% of the maxillary sinuses showed extensive pneumatization through the palatal process.

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.

Prevalence of Tympanostomy Tube Placement in Relation to Cleft Width and Type.

OBJECTIVES/HYPOTHESIS: The prevalence of tympanostomy tube surgery (TTS) in patients with a cleft deformity was investigated, in relation to cleft width and cleft type. STUDY DESIGN: Retrospective review of medical health records. METHODS: Retrospective review of medical health records. Seventy-eight patients with non-syndromic cleft deformity of the palate and/or alveolus and lip between 2003 and 2017 were investigated. All available medical documents were analyzed. The study group was divided into subgroups: 1) patients with isolated cleft palate (CP) and patients with a cleft palate with cleft lip and alveolus (CLP). 2) According to Veau's classification (I-IV), further subgroups were defined. Cleft width was measured using plaster cast models. RESULTS: TTS was performed in 55% of the patients (n = 43). Considering Veau's classification, TTS was conducted as follows: Veau I 65.2% (n = 15/23), Veau II 55.0% (n = 11/20), Veau III 47.6% (n = 10/21), and Veau IV 50.0% (n = 7/14). Cleft classifications, maxillary arch width, and absolute/relative cleft width had no statistical impact on TTS occurrence. Although no significant correlation could be found, patients in our study group with CP (Veau I and II) underwent TTS more often (60.5%, n = 26/43) than patients with CPL (Veau III and IV; 48.6%, n = 17/35) during a three-year follow-up. CONCLUSION: None of the cleft characteristics examined had a significant impact on the proportion of patients who received TTS. Nevertheless, patients with lower Veau classification and CP received tympanostomy tubes more often. Therefore, otolaryngologists and pediatricians treating children with cleft palate should maintain a high level of suspicion for chronic middle ear effusion, even in patients with small clefts. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:E2764-E2769, 2021.

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.

Virtual splint registration for electromagnetic and optical navigation in orbital and craniofacial surgery.

In intra-operative navigation, a registration procedure is performed to register the patient's position to the pre-operative imaging data. The registration process is the main factor that determines accuracy of the navigation feedback. In this study, a novel registration protocol for craniofacial surgery is presented, that utilizes a virtual splint with marker points. The accuracy of the proposed method was evaluated by two observers in five human cadaver heads, for optical and electromagnetic navigation, and compared to maxillary bone-anchored fiducial registration (optical and electromagnetic) and surface-based registration (electromagnetic). The results showed minimal differences in accuracy compared to bone-anchored fiducials at the level of the infra-orbital rim. Both point-based techniques had lower error estimates at the infraorbital rim than surface-based registration, but surface-based registration had the lowest loss of accuracy over target distance. An advantage over existing point-based registration methods (bone-anchored fiducials, existing splint techniques) is that radiological imaging does not need to be repeated, since the need for physical fiducials to be present in the image volume is eradicated. Other advantages include reduction of invasiveness compared to bone-achnored fiducials and a possible reduction of human error in the registration process.

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.

Correlation between craniofacial structures, anthropometric measurements, and nasopharyngeal dimensions in black adolescents.

OBJECTIVES: To evaluate the correlation between craniofacial structures, anthropometric measurements, and bony and soft tissue nasopharyngeal dimensions in African Black adolescents. METHODS: This retrospective cross-sectional study was conducted on 483 healthy adolescents (250 females and 233 males), randomly selected from one dental clinic. The inclusion criteria were skeletal and dental Class I, Black ethnicity, pubertal growth period as determined by the Greulich and Pyle atlas criteria, and no history of orthodontic treatment. Anthropometric measurements (stature, upper body height, lower body height, and BMI) and radiographic records (hand-wrist radiographs, and lateral cephalograms) were obtained. One investigator traced and analysed all cephalograms to determine three skeletal craniofacial parameters (maxillary length [Ar- ANS], mandibular length [Ar-Gn], and lower anterior facial height [ANS-Me]), and 14 (8 skeletal and 6 soft tissue) nasopharyngeal parameters. Pearson correlation coefficients and stepwise multiple linear regression analyses were conducted. RESULTS: The mean skeletal ages of females and males were 11.31±2.31y and 12.66±1.85y, respectively. Multiple linear regression analyses showed that stature, posterior height of nasal cavity (S-PNS), length of nasal floor (AA-PNS), and mean area of bony nasopharynx (Area 1) were significantly correlated with maxillary length, P<.001. Stature, BMI, S-PNS, vertical angle of nasopharynx (Ba-S-PNS), Area 1, adenoid height (AD), and linear hyoid bone measurements (H-AA, H-RGN, H-Ax) were all correlated with mandibular length, P<.05. Lower facial height showed sexual dimorphism and was significantly associated with vertical nasopharyngeal measurements, BMI and upper body height. CONCLUSIONS: Craniofacial structures were significantly associated with stature and upper body height. Maxillary growth was associated with bony nasopharyngeal variables. Mandibular growth and lower facial height were associated with bony and soft tissue nasopharyngeal variables. The sexual dimorphism in lower facial height warrants future studies to fully understand and manage the craniofacial complex and nasopharyngeal airway in African Black adolescents.

Positional Variation of the Infraorbital Foramen in Caucasians and Black Africans from Britain: Surgical Relevance and Comparison to the Existing Literature.

BACKGROUND: Midface augmentation and orbital surgery carry an inherent risk of injury to the infraorbital vascular bundle, especially the infraorbital nerve where it exits the infraorbital foramen (IOF). This can result in significant morbidity for the patient, including paresthesia and neuralgia. Studies report significant heterogeneity in IOF position according to gender, ethnicity, and laterality. A knowledge of the relationship of the IOF to regional soft tissue, bony landmarks, and its variation among ethnicities is likely to reduce iatrogenic injuries. METHODS: A single-center retrospective computed tomography (CT)-based study was conducted. Twenty Caucasians and 20 Black Africans patients were selected from an existing radiologic database at Moorfields Eye Hospital, London, UK. DICOM image viewing software (Syngo, Siemens Healthineers) was used to record the position of the IOF using standardized sagittal and axial views. RESULTS: There was a statistically significant difference in the horizontal position of the IOF in the 2 races (P = 0.00). The combined measurements were used to derive a rectangular zone of variability measuring 14.30 mm by 10.60 mm. This zone was found to lie 3.50 mm below the infraorbital rim, 7.10 mm medial to the piriform aperture, and 11.60 mm from the lateral orbital rim. CONCLUSION: A sound knowledge of key facial landmarks is necessitated when performing midface augmentation and orbital surgery. An anatomical safe zone depicting the variation of the IOF will help reduce iatrogenic injury to the infraorbital nerve and prevent patient morbidity.

Progressive Orbitotomy and Graduated Expansion of the Supraorbital Keyhole: A Comparison with Alternative Minimally Invasive Approaches to the Paraclinoid Region.

BACKGROUND: Various minimally invasive approaches, such as supraorbital (SO), minipterional (MPT), and translateral orbital (TLO), can access the paraclinoid region. Studies have described these approaches individually but have not directly compared all of them in the same anatomic specimen. METHODS: Using virtual reality models generated from computed tomography studies of living subjects, we simulated TLO, MPT, and variations of SO approaches, without and with removal of the orbital rim and sphenoid wing. We measured the area of freedom (AOF), distance, and angle of attack to 4 paraclinoid targets: anterior clinoid process, optic foramen, lateral superior orbital fissure, and maxillary strut. RESULTS: For superiorly positioned targets, such as anterior clinoid process and optic foramen, MPT provided a larger AOF compared with the supraorbital approach. However, with progressive drilling of the orbital roof and lesser wing of the sphenoid, the SO corridor AOF was equivalent to MPT at the anterior clinoid process and larger at the optic foramen (P = 0.003). To the lateral superior orbital fissure, TLO had the most limited AOF, and MPT had the greatest (P < 0.01 for all comparisons). For the maxillary strut, MPT, TLO, and SO with orbitotomy and sphenoidectomy all provided a similar AOF. CONCLUSIONS: For surgical targets in the paraclinoid region, MPT provided a greater AOF and shorter distance compared with TLO and limited SO approaches. With progressive enlargement of the SO corridor, SO with orbitotomy and sphenoidectomy matched and occasionally superseded the AOF of MPT. However, the AOF to inferomedial targets such as the maxillary strut was similar among all approaches.

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.