CBCT analysis of the relative position between maxillary central incisors and alveolar bone in Southern Chinese adults / 口腔疾病防治

Objective@#Exploring the position and bone wall thickness characteristics of the maxillary central incisors in Southern Chinese adults to provide a clinical reference for the design of immediate maxillary central incisor implantation surgery.@*Methods@#The hospital ethics committee approved the study, and the patients provided informed consent. CBCT images of 990 adult patients (aged 20-79 years) from the Stomatology Hospital (January 2018 to December 2021) were categorized based on the dental arch form and age-sex groups. Sagittal CBCT images of the maxillary central incisors were used to measure the labial and palatal bone thickness wall at 4 mm the CEJ to apical, the middle of the root, and the angle between the tooth long axis and the long axis of the alveolar process, to compare the thickness of the labial and palatal bone walls in samples of male and female patients, and to explore the relationship between the angle between the tooth long axis and the alveolar process long axis in samples of male and female patients in different age groups (20-39 years; 40-59 years; 60-79 years).@*Results@#Significant differences were found in the labiopalatine side of the alveolar bone of the maxillary incisor root position. A total of 95.8% (948/990) of the maxillary incisors were positioned more buccally, 4.1% (41/990) were positioned more midway, and 0.1% (1/990) were positioned more palatally. The thicknesses of the bone wall at the CEJ of 4 mm below the palatal side, the middle of the root, and at the apex were greater (1.82 ± 0.56 mm, 3.20 ± 1.10 mm, and 7.70 ± 2.00 mm, respectively) than those at the labial side (1.21 ± 0.32 mm, 0.89 ± 0.35 mm, and 1.86 ± 0.82 mm, respectively), with statistical significance (P<0.05). Male bone wall thickness was generally greater than female bone wall thickness (P<0.05). The angle between the long axis of male teeth and the alveolar bone was 14.77° ± 5.66°, while that of female teeth was 12.80° ± 5.70°, with a statistically significant difference (P<0.05). The angle between the long axis of teeth and the alveolar bone in the 40-59-year-old group and the 60-79-year-old group was greater than that in the 20-39-year-old group, and the difference was statistically significant (P<0.05).@*Conclusion@#A total of 95.8% of adults in South China have maxillary central incisors with root deviation toward the labial bone cortex. The thickness of the labial bone wall is much thinner than that of the labial bone wall, which is the middle of the thickness of the root. In Southern Chinese adults, the angle between the upper central incisor and the long axis of the alveolar bone in males is greater than that in females, and the degree of the angle increases with age. It is recommended to pay attention to the thickness of the bone wall around the root and the angle between the teeth before immediate implantation surgery to choose a reasonable implantation plan.

Occlusion development after premature loss of deciduous anterior teeth: preliminary results of a 24-month prospective cohort study

ABSTRACT Objective: This study aimed to evaluate occlusion development after premature loss or extraction of deciduous anterior teeth, by means of a prospective cohort study. Methods: Fifteen infants and children aged 1 to 5 years old were longitudinally assessed (with loss or extraction of deciduous anterior teeth [n = 9], and without tooth losses [n = 6]). Photographs and dental casts at the baseline and after 24 months of follow-up were performed. Dental casts were scanned, and linear measurements were made on the digitalized models (missing tooth space, arch perimeter, arch length, arch width, intercanine length and intercanine width). The t-test was used for groups comparisons (α = 0.05). Results: Individuals' mean age at baseline was 2.93 (± 1.18) years. No statistically significant differences were observed in the missing tooth space in the group with tooth loss during the 24 months of follow-up (p > 0.05). Arch perimeter, arch length, arch width, intercanine length and intercanine width did not show differences between the groups (p > 0.05). Qualitative photographic evaluation revealed other changes in the dental arches and occlusion, such as exfoliation and eruption of deciduous teeth, eruption of permanent teeth, self-correction or establishment of malocclusion, among others. Conclusion: The results suggest that the premature loss of deciduous anterior teeth does not affect the perimeter, length and width of the dental arches; however, other alterations that lead to malocclusion could be established.

RESUMO Objetivo: Este estudo teve como objetivo avaliar o desenvolvimento da oclusão após perda prematura ou extração de dentes decíduos anteriores, por meio de um estudo de coorte prospectivo. Métodos: Quinze bebês e crianças de 1 a 5 anos foram avaliados longitudinalmente (com perda ou extração de dentes anteriores decíduos [n = 9] e sem perdas dentárias [n = 6]). Foram realizadas fotografias e modelos dentais no início e após 24 meses de acompanhamento. Os modelos dentários foram escaneados e medidas lineares foram feitas nos modelos digitalizados (espaço dentário perdido, perímetro da arcada, comprimento da arcada, largura da arcada, comprimento intercaninos e largura intercaninos). O teste t foi utilizado para comparações entre grupos (α = 0,05). Resultados: A média de idade dos indivíduos no início do estudo foi de 2,93 (± 1,18) anos. Não foram observadas diferenças estatisticamente significativas no espaço dentário perdido no grupo com perda dentária durante os 24 meses de acompanhamento (p > 0,05). O perímetro da arcada, comprimento da arcada, largura da arcada, comprimento intercaninos e largura intercaninos não apresentaram diferenças entre os grupos (p> 0,05). A avaliação fotográfica qualitativa revelou alterações nas arcadas dentárias e na oclusão, como: esfoliação e erupção de dentes decíduos, erupção de dentes permanentes, autocorreção ou estabelecimento de má oclusão, entre outras. Conclusão: Os resultados sugerem que a perda prematura de dentes anteriores decíduos não afeta o perímetro, comprimento e largura das arcadas dentárias; entretanto, outras alterações que levam à má oclusão poderiam ser estabelecidas.

Posición del incisivo inferior en pacientes de clase esqueletal I y II según su biotipo facial en una muestra de una clínica privada, Cali 2014 - 2020

Introducción: la sínfisis mentoniana es la articulación cartilaginosa medial de los huesos mandibulares, su posición se relaciona con los diferentes biotipos y puede influir en la posición del incisivo inferior. Objetivo: determinar si existen variaciones en la posición del incisivo inferior, en pacientes clase II con diferentes biotipos. Materiales y métodos: se evaluaron la totalidad de tomografías de pacientes clase I y II esquelética que asistieron entre 2014 y 2020 a una clínica privada, teniendo una muestra total de 74 pacientes, caracterizándolos por sexo y edad. Se determinó biotipo facial, Incisor Mandibular Plane Angle, distancias a la sínfisis como el ACV-ACL y altura desde el ápice. Para el análisis se utilizó I-CAT Visión Q, para las medidas de las tomografías digitales y para el análisis estadístico Stata 17. Resultados: se en- contró un Incisor Mandibular Plane Angle mayor en pacientes clase II en los tres biotipos; los dolicofaciales clase II mostraron menor valor en corticales ACV-ACL, los pacientes mostraron mayor proinclinación en la clase II. La posición del incisivo en pacientes clase II presenta una proinclinación significativa en braquifaciales (p = 0.04). Conclusión: se encontraron variaciones entre los tres biotipos faciales en las diversas mediciones en pacientes clase I y II, el sexo femenino evidenció diferencias significativas en las clases en las medidas del Incisor Mandibular Plane Angle y la altura de la sínfisis a nivel del ápice; estos hallazgos son relevantes en el momento de realizar un tratamiento ortodóntico ya que puede limitar el movimiento de los incisivos inferiores.

Introduction: the mental symphysis is the medial cartilaginous joint of the mandibular bones, its position is related with the different biotypes and can influence the position of the lower incisor. Objective: to determine if there are variations in the position of the lower incisor, in class II patients with different biotypes. Materials and methods: all the tomography of skeletal class I and II patients who attended a private clinic between 2014 and 2020 were evaluated, having a total sample of 74 participants, characterizing the patients by sex and age. Facial biotype, Incisor Mandibular Plane Angle, distances to the symphysis such as the ACV-ACL and height from the apex were determined. For the analysis, I-CAT Vision Q was used for the measurements of the digital tomography and for the statistical analysis Stata 17. Results: a greater Incisor Mandibular Plane Angle in class II patients in the three biotypes was evident; class II dolichofacials showed a lower value in both cortical ACV-ACL, with the narrowest and longest measurement of the symphysis, the patients showed proclination in class II for both sexes, being higher for the male. The position of the incisor within the symphysis in class II patients presents a significant proclination in brachyfacial patients (p=0.04), despite presenting greater proclination, it maintains its apices centered within the symphysis. Conclusion: variations were found between the three facial biotypes in class I and II patients, it is relevant when performing orthodontic treatment since it can limit the movement of the lower incisors.

Prevalencia del segundo conducto en dientes anteroinferiores usando Tomografía Computadorizada Cone Beam / Second root canal prevalence in lower anterior teeth using Cone Beam Computed Tomography

Introducción: Es un error común pensar que los dientes anteroinferiores, por lo general, tienen un solo conducto radicular con una sola raíz. Sin embargo, un estudio realizado por Vertucci et. al., (1974), mostraron una alta prevalencia (13%) de dos conductos radiculares en los dientes anteroinferiores, lo que estimuló más investigaciones. Objetivo: El propósito de este estudio fue determinar la prevalencia del segundo conducto radicular en los dientes anteroinferiores en una población nicaragüense, estos fueron detectados por medio de tomografía computadorizada (Cone Beam). Materiales y Métodos: En el estudio se analizaron 293 piezas dentales, de canino a canino de la arcada inferior. Para realizar el análisis se utilizó el software libre Radiant DICOM Viewer 2021.2.2, se realizaron cortes sagitales, axiales y coronales para ver la prevalencia del segundo conducto radicular. Resultados: De las 293 piezas dentarias analizadas se encontró que 259 presentaban un solo conducto que correspondía al 88.4% y 34 dientes presentaban dos conductos que correspondían al 11.6%. De acuerdo con el análisis tomográfico, se encontró que en los cortes axiales y sagitales fue donde se observó la presencia del segundo conducto. Con respecto a la presencia del segundo conducto de acuerdo al tercio del canal radicular se identificó que la mayoría se presentó en el tercio medio (52.94%), seguido por coronal (29.41%) y por último el tercio apical (17.65%). De acuerdo con la clasificación de Vertucci se encontró que se presenta un mayor porcentaje del tipo I con 88.40%, seguido por el tipo III con 4.44%, después el tipo V con 3.41%, y el tipo II con 2.39%. El de menor porcentaje fue el tipo VI con 1.37%, mientras que, en las piezas analizadas, no se encontraron los tipos IV, VII y VIII. Conclusión: Basados en los resultados obtenidos en este estudio, la prevalencia de un segundo conducto en dientes anteroinferiores fue de 11.6%.

Title The prevalence of a second root canal in mandibular anterior teeth using Cone Beam Computed Tomography. Abstract Introduction: It is a common misconception that the mandibular anterior teeth usually have a single root canal with a single root. However, a study by Vertucci et. al., (1974), showed a high prevalence (13%) of two root canals in the lower anterior teeth, which stimulated further investigations. Objective: The purpose of this study was to determine the prevalence of the second root canal in the mandibular anterior teeth in a Nicaraguan population, these were detected by means of computed tomography (Cone Beam). Materials and methods: In the study, 293 teeth were analyzed, from canine to canine of the mandibular teeth. To perform the analysis, the free software Radiant DICOM Viewer 2021.2.2 was used, sagittal, axial and coronal views were made to see the prevalence of the second root canal. Results: Of the 293 teeth analyzed, it was found that 259 had a single root canal corresponding to 88.4%, and 34 teeth had two root canals corresponding to 11.6%. According to the tomographic analysis, it was found that the presence of the second root canal was observed only in the axial and sagittal views. Regarding the presence of the second canal according to the third of the root canal, it was identified that the majority presented in the middle third (52.94%), followed by coronal (29.41%) and finally the apical third (17.65%). According to the Vertucci classification, it was found that there is a higher percentage of type I with 88.40%, followed by type III with 4.44%, then type V with 3.41%, and type II with 2.39%. The one with the lowest percentage was type VI with 1.37%, while in the pieces analyzed, types IV, VII and VIII were not found. Conclusion: Based on the results obtained in this study, the prevalence of a second root canal in lower anterior teeth was 11.6%.

Tratamiento de la transposición de incisivos inferiores / Treatment of transposition of lower incisors

La transposición es el intercambio de la posición de dos dientes adyacentes durante los primeros años de la dentición mixta. El objetivo de la investigación fue evaluar los cambios clínicos de un caso con transposición parcial bilateral de incisivos laterales mandibulares. Se atendió una paciente de 8 años de edad, femenina, de raza blanca, síndrome de Clase II división 1, con transposición de los incisivos laterales con caninos inferiores. Fue tratada con un arco lingual de cierre horizontal, de alambre 0,032 y dos muelles de NiTi comprimidos desde el cierre horizontal del arco hasta una armella soldada a la banda que se colocó en ambos incisivos laterales. Se recuperó el espacio necesario para la erupción de los caninos inferiores y así mejoró la estética dental y facial de la paciente.

Transposition is the exchange of the position of two adjacent teeth during the first years of the mixed dentition. The objective of this research is to evaluate the clinical changes of a case with partial bilateral transposition of mandibular lateral incisors. We present an 8-year-old white female patient with Class II Division 1 malocclusion and transposition of the lateral incisors with lower canines. She was treated with a 0.032 wire horizontal closure lingual arch and two NiTi springs compressed from the horizontal closure of the arch to an eyebolt welded to the band that was placed on both lateral incisors. The necessary space for the eruption of the lower canines was recovered, thus improving her dental and facial aesthetics.

Concordance of the vestibular bone thickness at the level of point a between teleradiography and cone beam computed tomography / Concordancia del espesor óseo vestibular a nivel del punto a entre telerradiografía y tomografía computarizada de haz cónico

Objective: The aim of this study was to determine the concordance of the vestibular bone thickness measured at the level of point A between Teleradiography and Cone Beam Computed Tomography (CBCT). Materials and Methods: This study consisted of a cross-sectional analytical design of concordance that evaluated the teleradiographies and CBCTs of 32 patients. The measurements were performed by three evaluators, specialists in orthodontics. Two of them measured the CBCTs and one evaluated the teleradiographs. The concordance of both tests was determined using the Concordance Correlation Coefficient. Results: When evaluating the value of the vestibular bone thickness at the level of point A between the CBCT and the teleradiography, it was observed that the mean value of the absolute difference between the two was 0.95±0.74, 95%CI [0.68­1.22], being statistically significant (p=0.0027). When the concordance between both tests was analyzed, it was observed that it was poor (CCC=0.204 95%CI [0.014­0.394]), although statistically significant (p<0.00001). Conclusions: It was possible to conclude that there is no concordance in the measurement of the vestibular bone thickness at the level of Point A between the Teleradiography and the CBCT.

Objetivo: El objetivo de este estudio fue determinar la concordancia del espesor óseo vestibular medido a nivel del punto A entre la Telerradiografía y la Tomografía computarizada de haz cónico (CBCT). Materiales y Métodos: Esta investigación presentó un diseño analítico transversal de concordancia en el que se evaluaron las telerradiografías y CBCT de 32 pacientes. Las mediciones fueron realizadas por tres evaluadores especialistas en ortodoncia, dos de ellos midieron los CBCT y uno las telerradiografías. La concordancia de ambos exámenes fue medida mediante Coeficiente de Correlación de Concordancia. Resultados: Al evaluar el valor del grosor óseo vestibular a nivel del punto A entre el CBCT y la telerradiografía, se observó que el valor promedio de diferencia absoluta entre ambos fue de 0,95±0,74 IC95% [0,68­1,22], siendo estadísticamente significativas (p=0,0027). Cuando se analizó la concordancia entre ambos exámenes se observó que esta fue pobre (CCC=0,204 IC95 % [0,014­0,394]), aunque estadísticamente significativa (p<0,00001). Conclusión: Se pudo concluir que no existe concordancia en la medición del espesor óseo vestibular medido a nivel del Punto A entre la Telerradiografía y el CBCT.

Estimation of dental age using the kvaal method with digital panoramic radiographs in peruvian adults / Estimación de la edad dental según el método de Kvaal con radiografías panorámicas digitales en adultos peruanos

To determine the accuracy of the Kvaal method in the estimation of dental age through the analysis of digital panoramic radiographs of patients between 20 and 47 years of age who attended the stomatological clinic of the Universidad Científica del Sur, (2018 to 2019), Lima-Perú. 289 digital panoramic radiographs belonging to individuals of both sexes, aged 20 to 47 years were analyzed. Length and width measurements were obtained in the dental and pulp chamber in the upper central incisors. These data were subsequently evaluated by calculating the proportions between the pulp and root length of the upper central incisor by applying the formula of the method of Kvaal et al. to obtain the accuracy of the method in estimating dental age. Applying the formula of Kvaal et al. indicates that the relationship between the width of the pulp and the length of the root has a higher level of significance in relation to others proportions: M mean value of all ratios except T (-0.659) and W-L difference between W and L (-0.643). The coefficient of determination (r²) and standard error of estimation (SEE) using the original Kvaal formula is r²: 0.70, SEE: 4.90 years, then a modified Kvaal formula was proposed for the Peruvian population. The Method of Kvaal et al. has an accuracy of 1.24 in estimating the dental age of individuals, using the upper central incisor in digital panoramic radiographs.

Determinar la precisión del método de Kvaal en la estimación de la edad dental mediante el análisis de radiografías panorámicas digitales de pacientes entre 20 a 47 años atendidos en la clínica estomatológica de la Universidad Científica del Sur, (2018 a 2019), Lima-Perú. Se analizaron 289 radiografías panorámicas digitales pertenecientes a individuos de ambos sexos, de 20 a 47 años. Se obtuvo medidas de longitud y anchura en la cámara dental y pulpar en los incisivos centrales superiores. Estos datos se valoraron posteriormente al calcular las proporciones entre la pulpa y longitud de la raíz del incisivo central superior aplicando la fórmula del método de Kvaal et al. para obtener la precisión del método en la estimación de la edad dental. Al aplicar la fórmula de Kvaal et al. indica que la relación entre la anchura de pulpa y la longitud de la raíz presentan un nivel de significancia mayor en relación a otras proporciones: M valor medio de todas las proporciones excepto T (-0.659) y W-L: diferencia entre los valores de W y L (-0.643). El coeficiente de determinación (r²) y el error estándar de la estimación (SEE) utilizando la fórmula original de Kvaal es de r²: 0.70, SEE: 4.90 años, después se propuso una fórmula modificada de Kvaal para la población peruana. El Método de Kvaal et al. tiene una precisión del 1.24 en la estimación de la edad dental de los individuos, utilizando el incisivo central superior en radiografías panorámicas digitales.

Cephalometric Evaluation of Maxillary Incisors Torque and Vertical Changes Utilizing Standard Edgewise Mechanics

In 1995 Gebeck & Merrifield studied a successful and unsuccessful treated Class I and Class II's samples; they found a -1.33 mm intrusion in the former and a 0.80 mm extrusion in the latter. The purpose of this article was to perform a cephalometric evaluation of maxillary incisors torque and vertical changes. We studied a sample of 129 patients, 30 males and 99 females, taken from The Charles H. Tweed Foundation Long Term Study, at pretreatment mean age 12.93 years, posttreatment mean age 16.19 years and follow up post retention mean age 29.83 years, a 13.88 years interval. The records were collected from private practitioners across the North American continent who used Standard Edgewise Mechanics and were members of the Charles H. Tweed Foundation. All patients were Class I and II American whites treated with the extraction of 4 premolars. We found an Upper anterior incisal edge to PP vertical linear measurement 28.7 and 29.2 mm, +0.53 mm (p<0.019) from pretreatment to posttreatment. The average Upper 1 to SN angle was 103.2 ° at pretreatment and 100.1° at posttreatment, -3.2° (p<0.000), Upper 1 to PP 111.0° and 108.9°, -2.2° (p<0.000), the three of them statistically significant. Conversely, Upper 1 to commissure was not. The four measurements were also statistically significant posttreatment to follow up, upper anteriors kept losing torque after posttreatment, and less upper anteriors surface was below the commissure. Some torque loss and vertical extrusion can be expected while treating patients with extractions of four premolars, therefore, upper incisor inclination increase and vertical change by itself cannot determine the success of treatment.

En 1995, Gebeck y Merrifield estudiaron muestras de Clase I y Clase II tratadas con éxito y sin éxito; encontraron una intrusión de -1,33 mm en el primero y una extrusión de 0,80 mm en el segundo. El propósito de este artículo fue realizar una evaluación cefalométrica del torque y los cambios verticales de los incisivos maxilares. Estudiamos una muestra de 129 pacientes, 30 hombres y 99 mujeres, tomados del estudio a largo plazo de la Fundación Charles H. Tweed, con una edad media previa al tratamiento de 12,93 años, una edad media posterior al tratamiento de 16,19 años y una edad media de seguimiento posterior a la retención de 29,83 años, con un intervalo de de 13,88 años. Los registros se recopilaron de médicos privados en todo el continente norteamericano que utilizaron Standard Edgewise Mechanics y eran miembros de la Fundación Charles H. Tweed. Todos los pacientes eran blancos americanos Clase I y II tratados con extracción de 4 premolares. Encontramos una medida lineal vertical del borde incisal anterior superior a PP de 28,7 y 29,2 mm, +0,53 mm (p<0,019) desde el pretratamiento hasta el postratamiento. El promedio del ángulo Superior 1 a SN fue de 103,2° en el pretratamiento y 100,1° en el postratamiento, -3,2° (p<0,000), Superior 1 a PP 111,0° y 108,9°, -2,2° (p<0,000), los tres estadísticamente significante. Por el contrario, Superior 1 a la comisura no lo era. Las cuatro mediciones también fueron estadísticamente significativas para el seguimiento después del tratamiento, los dientes anteriores superiores siguieron perdiendo torsión después del tratamiento y se observó menor superficie de los dientes anteriores superiores debajo de la comisura. Se puede esperar cierta pérdida de torque y extrusión vertical al tratar a pacientes con extracciones de cuatro premolares, por lo tanto, el aumento de la inclinación del incisivo superior y el cambio vertical por sí mismos no pueden determinar el éxito del tratamiento.

An atypical presentation of talon cusp: Double talon cusps

Talon cusp is an uncommon developmental anomaly resulting in an extra cusp or cuspal projection on an anterior tooth consisting of normal enamel, dentin, and varying degrees of pulp tissue. Talon cusp shows varied presentations of which the palatal talon cusp has been the most common of all. The management requires an extensive understanding of this clinical entity and the complications associated with its occurrence. In this case series, we are reporting double talon cusps which is a rarity itself, involving the palatal aspect of maxillary central incisors

Multidisciplinary treatment of Class I Angle Malocclusion with severe crowding and peg lateral incisor: A case report

@#Class I malocclusions with severe crowding and tooth size discrepancies may be successfully treated orthodontically with extraction therapy, and co-management with other specialists. Correction of the discrepancies will optimize occlusal result (overjet, overbite, midline shift, and smile esthetics). This is a case of a 19-year-old male with severe crowding in upper and lower teeth and peg lateral incisor. The patient had malocclusion Class I. This case was treated comprehensively and successfully using fixed orthodontic appliances with extraction of four premolars, and veneer composite for peg lateral incisor with the help of a conservative dentist at the end of orthodontic treatment.

Cognition about emergency management of avulsed incisor in children among dentists in Guangdong province / 华西口腔医学杂志

OBJECTIVES@#This study aimed to evaluate and analyze the current situation of dentists in Guangdong pro-vince regarding the management of avulsed incisors, thereby providing a reference for making treatment strategies for avulsed incisors in the future.@*METHODS@#A total of 712 dentists with different educational backgrounds and working conditions in Guangdong province were randomly selected to conduct an online questionnaire survey on the cognition of children with avulsed incisors from April 2022 to May 2022. The data were recorded by Excel software and statistics were analyzed on Stata/SE 15.1.@*RESULTS@#A total of 712 dentists were investigated and 701 questionnaires were collected (98.46%). In addition, 65.9% of investigators came from the Department of Stomatology in a First-class Hospital or Stomatological Hospital. The results showed that the average number of avulsed teeth consulted by dentists was less than 20 per year. Although 99.7% of respondents considered normal saline as a suitable storage medium, 3.1% and 23.8% of them had a misunderstanding that the tap/alcohol could be used for root cleaning. Moreover, 93.4% was the correct selection rate of the treatment plan for processing on root surfaces before replanting by investigators. The correct selection rate of the duration using elastic fixation was only 10.7%. Meanwhile, 42.9% of investigators refused to inoculate tetanus immunoglobulin after teeth replanting. Emergency management of dental avulsion (EM) and clinical management of dental avulsion (CM) answered correctly with average scores of 14.60±11.85 and 14.48±2.67, respectively. Multivariate linear regression analysis revealed that working years were negatively correlated with EM and CM scores (P<0.05). There was a positive correlation between CM and EM scores with the number of avulsion cases treated by physicians each year (P<0.05). In terms of the EM score of dentists' learning attitude, investigators who had received enough knowledge were higher than those who had not and insufficient knowledge reserved, and the difference was statistically significant (P<0.05). The scores of investigators who thought they had a certain degree of knowledge about dental trauma were higher than those who thought they "did not understand", and the difference was statistically significant (P<0.05). In terms of CM scores, investigators who thought the knowledge of dental trauma was "very helpful" had higher scores than those who thought it was "not helpful", and the difference was statistically significant (P<0.05). The scores of the investigators who thought they had "relatively sufficient knowledge" of dental trauma were higher than those who thought they had "no knowledge" or "insufficient know-ledge", and the difference was statistically significant (P<0.05).@*CONCLUSIONS@#The overall accuracy of the management of avulsed incisors among dentists was low in Guangdong province. Dentists were more likely to have a higher rate of accuracy choice in treatment options for luxation injury and avulsion to enhance the prognosis of replanted teeth.

Achieved intrusion amount of the maxillary incisors and the influencing factors in clear aligner extraction cases / 口腔疾病防治

Objective @#To investigate the achieved intrusion amount of the maxillary incisors and the influencing factors in clear aligner cases treated with extraction of premolars. @*Methods @#This study has been reviewed and approved by the Ethics Committee, and informed consent has been obtained from patients. Thirty adult female patients who underwent extraction of the bilateral maxillary first premolars followed by clear aligner therapy were included. CBCT data before and after treatment were obtained, and three-dimensional reconstruction with registration alignment was performed. A spatial coordinate system was established, and the achieved intrusion amount was measured, followed by calculation of the intrusion efficacy. The factors related to the achieved intrusion amount were investigated through multiple linear regression analysis.@*Results @#The overall efficacy of maxillary incisor intrusion was 54%, with the maxillary central incisors (48%) lower than the lateral incisors (59%), which was statistically significant (P<0.001). Regression analysis showed that the designed intrusion amount and the stepwise intrusion design were positively correlated with the achieved intrusion amount. The designed retroclination amount and use of class Ⅱ intermaxillary elastics were negatively correlated with the achieved intrusion amount. The initial overbite, overjet, crowding, upper central incisor inclination, amount of the first series of aligners, canine attachment type, posterior teeth attachment type and bite ramps had no significant correlation with the achieved intrusion amount.@*Conclusion@# In maxillary first premolar extraction cases treated with clear aligners, the upper central incisors have lower efficacy of intrusion movement than the lateral incisors. The achieved intrusion amount of maxillary incisors was influenced by multiple factors, which should be considered comprehensively for better vertical control in such cases.

Three-dimensional finite element analysis of the influence of implant site and axial direction on the immediate weight bearing stress of central incisors in different alveolar fossa shapes / 口腔医学

Objective@#To analyze and investigate the effects of implant location and axial direction on the stress distribution of implants, abutments, central screws, and crowns during immediate loading of maxillary mesial incisors with different alveolar fossa morphology based on three-dimensional finite element method.@*Methods@#Referring to the oral CBCT images of a healthy adult, a three-dimensional finite element model was established for immediate implant loading of maxillary central incisors with three alveolar fossa morphs: labial, intermediate, and palatal; different implant sites(apical site, palatal/labial site) and axes(tooth long axis, alveolar bone long axis) were simulated; the established model was loaded with a force of 100 N. ANSYS software was applied to analyze the stress values of the implants, abutments, central screwss, and crownss. @*Results@#The 3D finite element models of 12 maxillary central incisors with different alveolar sockets were successfully established;the implants and their superstructures were least stressed when the maxillary central incisors with partial labial and partial palatal shape were placed along the long axis of the alveolar bone in the palatal/labial position for immediate implant loading;the implants and their superstructures were least stressed when the maxillary central incisors with central shape were placed along the long axis of the tooth in the palatal position for immediate implant loading. The implant and its superstructure were subjected to the least stress when the implant was placed along the long axis of the tooth in the immediate loading position. @*Conclusion@#The bio-mechanical characteristics of the implant and its superstructure are influenced by the different socket morphology, implantation sites and axes. Therefore, in clinical practice, different implantation axes and implantation sites should be developed for different socket morphs.

Histological study of platelet-rich fibrin combined with MTA for direct pulp capping of rabbit teeth / 口腔疾病防治

Objective @# To investigate the outcomes of a novel direct pulp capping agent containing platelet-rich fibrin (PRF) and mineral trioxide aggregate (MTA). @*Methods @# A total of 32 New Zealand rabbits were randomly divided into 4 groups, namely, the PRF+MTA group (P+M group), PRF group (P group), MTA group (M group) and blank control group (BC group), with 8 rabbits per group. Dental pulp exposure and direct pulp capping were performed, and complete crown square sealing was performed on 2 mandibular central incisor teeth of each rabbit. Four rabbits from each group were euthanized after each observation period (7 and 28 days). The experimental teeth were subjected to HE staining. Inflammatory cell infiltration, calcified bridge formation and pulp tissue disorganization were observed and graded. @*Results@#Inflammatory cell infiltration: on the 7th day, group P+M and group M were lighter than group BC (P<0.05); on the 28th day, group P+M was lighter than group P and group BC (P<0.05); group P+M and group M did not significantly differ (P>0.05). Calcified bridge formation: on the 7th and 28th days, group P+M was lighter than group P, group M and group BC (P<0.05); on the 28th day, group M was higher than group BC (P<0.05). Under microscope, the calcified bridge contained cellular components and was surrounded by odontoblast-like cells, sharing a structure resembled osteodentin; dentin tubule-like structure could not be observed in calcified bridge, and the calcified bridge resembled certain points of osteodentin. Pulp tissue disorganization: on the 7th day, group P+M and group M were lighter than group BC (P<0.05); on the 28th day, group P+M was lighter than group P and group BC (P<0.05). group P+M and group M did not significantly differ (P>0.05). @*Conclusion @# The combination of PRF and MTA for direct pulp capping provided light inflammatory cell infiltration, stable pulp status and a strong ability of pulp tissue to form calcified bridge, and the calcified bridge resembled certain points of osteodentin.

Effects of Implant Sites and Axial Direction on Stress of Maxillary Central Incisors with Immediate Implantation under Immediate Weight-Bearing: A Three-Dimensional Finite Element Analysis / 医用生物力学

Objective To investigate the influence of implant location and axial direction on stress distributions at the implant bone interface of maxillary central incisors with different alveolar fossa morphology by immediate implantation under immediate weight-bearing. Methods With reference to dental cone beam computed tomography (CBCT) image data from a healthy adult, the three-dimensional ( 3D) finite element models of maxillary central incisors with three types of alveolar fossa ( buccal, mediate, and palatal type) by immediate implatation under immediate weight-bearing were established. Different implant sites ( apical site, palatal / labial site) and axial directions (long axis of the tooth, long axis of the alveolar bone) were simulated. The established models were subjected to 100 N force at different angles (0°, 30°, 45°, 60°, 90°). The stresses in the alveolar bone around the implant were analyzed by the ANSYS software. Results Twelve 3D finite element models of maxillary central incisors with different alveolar fossa morphology by immediate implantation under immediate weight-bearing were successfully established. When alveolar fossa with buccal and mediate shape was applied with immediate implantation under immediate weight-bearing, it was easier to obtain good biomechanical properties of the implant-bone interface when implants were placed at palatal site along long axis of the alveolar bone. When alveolar fossa with palatal shape was applied with immediate implantation under immediate weight bearing, the equivalent stresses on peri-implant alveolar bone were much smaller than those on apical site, regardless of whether the implant was placed along long axis of the tooth or the long axis of the alveolar bone. Conclusions Different alveolar fossa morphology, implant location and axial direction will affect characteristics of implant-bone interface of maxillary central incisors with immediate implantation under immediateweight-bearing. In clinical practice, surgical planning on different axial direction and location of implantation should be developed for alveolar fossa with different morphology.

Study on the ideal sagittal position of the lower third of the face in high-angle patients with different forehead forms / 口腔疾病防治

Objective@#To explore the ideal sagittal position of the lower third of the face in high-angle patients with different forehead forms and to provide a reference for clinical treatment. @*Methods@#Informed consent and portrait authorization were obtained from all patients, and the study passed the ethical review of the unit. We categorized forehead forms into four types: straight, rounded, type I angular (angled at the middle third of the forehead) and type II angular (angled at the upper third of the forehead). Profiles of high-angle patients with different forehead forms were collected. The initial position was when the facial axis point (FA point) was positioned at the goal anterior-limit line (GALL). After being silhouetted, the lower third of the face was moved forward and backward by 1 mm, 2 mm, 3 mm, and 4 mm each, plus the initial silhouetted picture, to obtain 9 images for each patient. A survey was created with these lateral profile silhouettes, and the silhouette images were ranked by 30 orthodontists and 30 laypersons. @*Results@# There were significant differences in profile scores at different movement distances of the lower third of the face among high-angle patients with different forehead shapes (P<0.05). Overall, high-angle patients with straight or type II angular foreheads had higher scores when the lower third of the face did not move. For high-angle patients with a rounded forehead, orthodontists and laypersons gave the highest scores when the lower third of the face was moved backward by 2 mm and 4 mm, respectively. For high-angle patients with a type I angular forehead, orthodontists thought the scores of backward movement of 4 mm were the highest, and laypersons thought the scores of backward movement of 3 mm were the highest. No significant difference was found in scores between orthodontists and laypersons (P>0.05). @*Conclusion @#The forehead forms and the sagittal position of the lower third of the face will affect the face’s profile aesthetics. Patients with straight and type Ⅱ angular foreheads has the best profile when the FA point is located on the GALL line. For patients with rounded and type Ⅰ angular foreheads, a posterior location of the lower third of the face is more desirable than the initial position.

Síndrome del incisivo central maxilar único: reporte de caso

El síndrome del incisivo central maxilar único es una rara alteración en el desarrollo y formación de órganos ubicados principalmente en la línea media; el cual ocurre de manera temprana entre los días 35 al 38 de vida intrauterina. Su etiología es desconocida, aunque se ha asociado a deleciones de los cromosomas 7 (7q.36.1) y 8, y a mutaciones en el gen Sonic Hedgehog. Presenta una prevalencia de 1/50.000 nacidos vivos y aunque es una anomalía poco frecuente del desarrollo craneofacial, su diagnóstico y tratamiento temprano son importantes para los odontólogos generales o especialistas ya que puede ser un signo de otras anomalías congénitas o del desarrollo graves. Por lo tanto, el objetivo de este caso es reportar la fase inicial de tratamiento en un niño con el síndrome de incisivo central maxilar único quien no había sido diagnosticado anteriormente con este síndrome. Caso Clínico: Paciente masculino de 10 años de edad, procedente de Jamundí, Valle del Cauca- Colombia. Reporta ausencia de órgano dentario superior. En el examen intraoral se observa un incisivo central único sobre la línea media del maxilar, ausencia de frenillo labial y papila incisiva, paladar oval y retrognatismo mandibular. Fue tratado en una primera fase con ortopedia funcional maxilar para mejorar la clase II y está a la espera de iniciar la segunda fase de tratamiento con ortodoncia. Conclusiones: El síndrome de incisivo central maxilar único es un síndrome poco frecuente el cual conlleva múltiples afecciones que interfieren en el normal desarrollo y crecimiento de estructuras anatómicas.

A síndrome do incisivo central superior único é uma alteração rara no desenvolvimento e formação de órgãos localizados principalmente na linha média; que ocorre precocemente entre os dias 35 a 38 de vida intrauterina. Sua etiologia é desconhecida, embora tenha sido associada a deleções dos cromossomos 7 (7q.36.1) e 8, e mutações no gene Sonic Hedgehog. Tem uma prevalência de 1/50.000 nascidos vivos e, embora seja uma anomalia rara do desenvolvimento craniofacial, seu diagnóstico e tratamento precoces são importantes para dentistas gerais ou especialistas, pois pode ser sinal de outras anomalias congênitas ou de desenvolvimento graves. Portanto, o objetivo deste caso é relatar a fase inicial do tratamento em uma criança com síndrome do incisivo central superior único que não havia sido previamente diagnosticada com essa síndrome. Caso clínico: Paciente do sexo masculino, 10 anos, procedente de Jamundí, Valle del Cauca- Colômbia. Relata ausência de órgão dentário superior. O exame intraoral mostra um único incisivo central na linha média maxilar, ausência de frênulo labial e papila incisiva, palato oval e retrognatismo mandibular. Foi tratado numa primeira fase com ortopedia funcional maxilar para melhorar a classe II e aguarda para iniciar a segunda fase do tratamento ortodôntico. Conclusões: A síndrome do incisivo central superior único é uma síndrome rara que envolve múltiplas condições que interferem no desenvolvimento e crescimento normal das estruturas anatômicas.

Solitary maxillary central incisor syndrome is a rare alteration in the development and formation of organs located mainly in the midline; which occurs early between days 35 to 38 of intrauterine life. Its etiology is unknown, although it has been associated with deletions of chromosomes 7 (7q.36.1) and 8, and mutations in the Sonic Hedgehog gene. It has a prevalence of 1/50,000 live births and although it is a rare anomaly of craniofacial development, its early diagnosis and treatment are important for general dentists or specialists since it can be a sign of other serious congenital or developmental anomalies. Therefore, the objective of this case is to report the initial phase of treatment in a child with solitary maxillary central incisor syndrome who had not been previously diagnosed with this syndrome. Clinical case: Male patient, 10 years old, from Jamundí, Valle del Cauca- Colombia. Reports absence of upper dental organ. Intraoral examination shows a solitary central incisor on the maxillary midline, absence of labial frenulum and incisive papilla, oval palate and mandibular retrognathism. He was treated in a first phase with maxillary functional orthopedics to improve class II and is waiting to start the second phase of orthodontic treatment. Conclusions: Solitary maxillary central incisor syndrome is a rare syndrome which involves multiple conditions that interfere with the normal development and growth of anatomical structures.

Presentation of infrequent clinical case of dental gemination of the permanent upper left lateral incisor

Introduction: Gemination is the division of a dental follicle that results in a tooth with two crowns, where the number of teeth in the arch does not vary. It constitutes an anomaly that is little diagnosed due to its presentation and therefore little treated, which requires an adequate study. Objective: To present an infrequent clinical case of dental gemination of the permanent upper left lateral incisor. Clinical case: 20-year-old patient with 30 weeks of gestational status treated for periodic review by appointment of her dentist. The intraoral examination revealed: the permanent upper left lateral incisor (tooth 22) with two crowns, one of which had lost the gingival wall and the other had second degree dental caries on the mesial side. Periapical radiography performed 1 year earlier showed tooth 22 with a partially divided pulp chamber and a broad, bifid, well-defined crown. Dental gemination of the permanent maxillary left lateral incisor was diagnosed. The geminated tooth was extracted, and the patient was referred to a dental prosthesis for rehabilitation. Conclusions: Dental gemination of the permanent upper left lateral incisor in a pregnant patient, constitutes an anomaly of the shape of the teeth that is infrequent in consultations.

Introducción: La geminación es la división de un folículo dentario que resulta en un diente de dos coronas, pero la cantidad de dientes de la arcada no varía. Constituye una anomalía poco diagnosticada por su presentación y por ende poco tratada, lo que necesita de un adecuado estudio. Objetivo: Presentar un caso clínico infrecuente de geminación dentaria del incisivo lateral superior izquierdo permanente. Caso clínico: Paciente de 20 años de edad, con 30 semanas de estado gestacional atendida para revisión periódica por citación de su estomatólogo. Al examen intraoral se detectó: el incisivo lateral superior izquierdo permanente (diente 22) con dos coronas, una de las cuales había perdido la pared gingival y la otra presentaba caries dental de segundo grado en cara mesial. La radiografía periapical realizada 1 año antes mostró el diente 22 con cámara pulpar parcialmente dividida y una corona ancha, bífida y bien definida. Se diagnosticó una geminación dentaria del incisivo lateral superior izquierdo permanente. Se realizó exodoncia del diente geminado y se remitió a la paciente a prótesis estomatológica para rehabilitación. Conclusiones: La geminación dentaria del incisivo lateral superior izquierdo permanente en una paciente embarazada es una anomalía de forma de los dientes poco frecuente en las consultas.

Síndrome del incisivo central maxilar medio único en neonato / Solitary median maxillary central incisor syndrome in neonates / Síndrome do incisivo central maxilar médio solitário em neonatos

Introducción: el síndrome del incisivo central maxilar medio único (SMMCI) es un trastorno de etiología desconocida, con base genética heterogénea, que se caracteriza por la erupción de un único incisivo central en el maxilar y que se puede relacionar con multitud de patologías y síndromes, entre los que destacan las alteraciones de la línea media, obstrucción nasal congénita, disfunción hipofisaria, talla baja y holoprosencefalia. Caso clínico: neonato mujer con síndrome dismórfico no filiado y obstrucción nasal congénita, que es diagnosticada de SMMCI tras consultar en repetidas ocasiones por cuadros de dificultad respiratoria y problemas para alimentarse. Conclusiones: el conocimiento de este raro síndrome es fundamental para la realización de un diagnóstico precoz por parte del equipo pediátrico y obstétrico, ya que un diagnóstico temprano es posible, mejorando la evaluación prenatal ecográfica, así como el adecuado manejo posnatal multidisciplinar posterior de nuestros pacientes.

Introduction: the Solitary Median Maxillary Central Incisor Syndrome (SMMCI) is a disorder of unknown etiology, with a heterogeneous genetic basis, characterized by the eruption of a single central incisor in the maxilla and that can be linked to various pathologies and syndromes, among which the alterations of the midline, congenital nasal obstruction, pituitary dysfunction, short stature and holoprosencephaly stand out. Clinical case: female newborns with unknown dysmorphic syndrome and congenital nasal obstruction, diagnosed with SMMCI after repeated consultations due to respiratory distress and feeding problems. Conclusions: understanding this rare syndrome is essential for an early diagnosis to be carried out by the pediatric and obstetric team, since it will improve the ultrasound prenatal assessment, as well as the adequate subsequent multidisciplinary postnatal patient management procedures.

Introdução: a síndrome do incisivo central maxilar médio solitário (SICMMS) é uma desordem de etiologia desconhecida, com base genética heterogênea, caracterizada pela erupção de um único incisivo central na maxila e que pode estar relacionada a uma infinidade de patologias e síndromes. onde se destacam alterações da linha média, obstrução nasal congênita, disfunção hipofisária, baixa estatura e holoprosencefalia. Caso clínico: recém-nascida com síndrome dismórfica de origem desconhecida e obstrução nasal congênita, diagnosticada com SICMSS após várias consultas por desconforto respiratório e problemas de alimentação. Conclusões: o conhecimento desta rara síndrome é essencial para que a equipe pediátrica e obstétrica possa fazer um diagnóstico precoce, pois ele pode melhorar a avaliação ultrassonográfica pré-natal, bem como o adequado manejo pós-natal multidisciplinar pós-natal dos pacientes.

Relación entre la inclinación de los incisivos con la estabilidad en la alineación del sector anterior según criterios del índice PAR

Introducción : el objetivo de este estudio fue el evaluar la relación entre la inclinación de los incisivos al finalizar tratamiento de ortodoncia con la estabilidad de la alineación de dientes anteriores usando índice PAR. Métodos: estudio analítico de corte transversal, en 47 pacientes que finalizaron ortodoncia, con radiografía lateral inicial y final, se evaluó el ángulo formado entre plano (Silla-Nasion) (U1-NS) e inclinación del incisivo superior y el ángulo entre inclinación axial del incisivo inferior y plano mandibular (Go-Gn). Se aplicó el índice PAR del sector anterior a modelos pretratamiento (T0), postratamiento (T1) y de seguimiento (T2). El análisis estadístico se realizó mediante distribuciones de frecuencias y porcentuales, prueba T, Anova I, Anova II y Manova; significancia P= 0.05. Resultados: no se encontró asociación entre la inclinación del incisivo superior e inferior, la estabilidad en alineación y el puntaje ponderado del PAR entre T2-T1 (P>0.05). El PAR disminuyó 75.29% de T0 a T1 y 58.79% de T0 aT2, con recidiva de 16,5%. No hubo asociación entre tipo de retenedor y puntaje ponderado del PAR. De T0 a T2 hubo asociación entre la interacción de la inclinación del incisivo superior (P=0.03) e inferior (P=0.04), con el puntaje total ponderado del índice PAR. Conclusión: no hubo asociación entre la modificación de la inclinación de los incisivos con la estabilidad del sector anterior. Al terminar ortodoncia se presentó un nivel de corrección alto en el sector antero-superior e inferior, sin embargo, hubo recidiva de 16.5%.

Introduction: the objective of this study was to evaluate the relationship between incisor inclination at the end of orthodontic treatment with the anterior teeth alignment stability using PAR index. Methods: analytical cross-sectional study, the angle formed between the plane (Silla-Nasion) (U1-NS) and the inclination of the upper incisor and the angle between axial inclination of the lower incisor and mandibular plane (Go-Gn), were measured in 47 initial and final lateral radiographs of patients who finished orthodontic treatment. The anterior sector PAR index was applied to pretreatment (T0), posttreatment (T1) and follow-up (T2) casts. Statistical analysis was performed using frequency and percentage distributions, T test, Anova I, Anova II and Manova; significance p = 0,05. Results: no association was found between upper and lower incisor inclination, alignment stability and PAR weighted score between T2-T1 (p> 0,05). The PAR decreased 75,29% from T0 to T1 and 58,79% from T0 to T2, with a recurrence of 16,5%. There was no association between retainer type and PAR weighted score. From T0 to T2 there was an association between the interaction of the incisor inclination of upper (p = 0,03) and lower (p = 0,04), with the weighted total score of the PAR index. Conclusion: there was no association between the modification of the incisor inclination with the stability of the anterior sector. At the end of orthodontic treatment there was a high level of correction in the anterior-superior and inferior sector, however, there was a recurrence of 16,5%.