Pain Patterns of the Temporomandibular Joint Dysfunction and Implications of Stress-Related Behaviors: A Pilot Study / Patrones de Dolor de la Disfunción de la Articulación Temporomandibular e Implicaciones de los Comportamientos Relacionados con el Estrés: Un Estudio Piloto

SUMMARY: Temporomandibular joint dysfunction interferes with the quality of life and activities of daily living among patients. The symptoms of temporomandibular dysfunction, including pain and clicking and popping sounds, are worsened during stressful events, and patients report increased pain around the temporomandibular joint. Stress-related behaviors, such as teeth clenching and teeth grinding, are commonly reported as increasing during stress. The prevalence of temporomandibular dysfunction and stress-related behaviors is reported differently in the literature. Stress in higher education is common. The purpose of this pilot study was to investigate the prevalence of temporomandibular joint dysfunction and stress-related behaviors among staff members at a local University. The study also sought to explore pain patterns described by people experiencing temporomandibular joint dysfunction and the relationship between stress-related behaviors and pain symptoms experienced. Further, the impact of stress on symptoms experienced by people with temporomandibular dysfunction was investigated in this pilot study.

La disfunción de la articulación temporomandibular interfiere con la calidad de vida y las actividades de la vida diaria entre los pacientes. Los síntomas de la disfunción temporomandibular, incluidos el dolor y los chasquidos, empeoran durante los eventos estresantes, y los pacientes informan un aumento del dolor alrededor de la articulación temporomandibular. Los comportamientos relacionados con el estrés, como apretar y rechinar los dientes, suelen aumentar durante el estrés. La prevalencia de la disfunción temporomandibular y los comportamientos relacionados con el estrés se informa de manera diferente en la literatura. El estrés en la educación superior es común. El propósito de este estudio piloto fue investigar la prevalencia de la disfunción de la articulación temporomandibular y los comportamientos relacionados con el estrés entre los miembros del personal de una universidad local. El objetivo del estudio además fue explorar los patrones de dolor descritos por personas que experimentan disfunción de la articulación temporomandibular y la relación entre los comportamientos relacionados con el estrés y los síntomas de dolor experimentados. Además, en este estudio piloto se investigó el impacto del estrés en los síntomas que experimentan las personas con disfunción temporomandibular.

In-office dental bleaching in adolescents using 6% hydrogen peroxide with and without gingival barrier: a randomized double-blind clinical trial

Abstract At low concentrations used for in-office bleaching gels, such as 6% HP, gingival barrier continues to be performed. If we take into account that, in the at-home bleaching technique, no barrier is indicated, it seems that the use of a gingival barrier fails to make much sense when bleaching gel in low concentration is used for in-office bleaching. Objective This double-blind, split-mouth, randomized clinical trial evaluated the gingival irritation (GI) of in-office bleaching using 6% hydrogen peroxide (HP) with and without a gingival barrier in adolescents, as well as color change and the impact of oral condition on quality of life. Methodology Overall, 60 participants were randomized into which side would or would not receive the gingival barrier. In-office bleaching was performed for 50 minutes with 6% HP in three sessions. The absolute risk and intensity of GI were assessed with a visual analogue scale. Color change was assessed using a digital spectrophotometer and color guides. The impact of oral condition on quality of life was assessed using the Brazilian version of the Oral Health Impact Profile (α=0.05). Results The proportion of patients who presented GI for the "with barrier" group was 31.6% and for the "without barrier" group, 30% (p=1.0). There is an equivalence for the evaluated groups regarding GI intensity (p<0.01). Color change was detected with no statistical differences (p>0.29). There was a significant impact of oral condition on quality of life after bleaching (p<0.001). Conclusions The use or not of the gingival barrier for in-office bleaching with 6% HP was equivalent for GI, as well as for bleaching efficacy, with improvement in the impact of oral condition on quality of life.

Dental age estimation by assessing the pulp volume of five teeth in a peruvian population using cone beam computed tomography images / Estimación de la edad dental evaluando el volumen pulpar de cinco dientes utilizando imágenes de tomografías computarizadas de haz cónico en una población peruana

Abstract Dental age estimation is very important for individual identification in criminal and civil forensic investigations. One of the methods for age estimation is studying age related changes in pulp volume of teeth. The objective of the current study was to estimate dental age from the pulp volume of five different categories of teeth of a Peruvian sample using cone beam computed tomography (CBCT). Retrospective CBCT records of 231 patients (females (134), males (97), age: 12-60 years) were included in the study, categorized into five different age groups (12-19, 20-29, 30-39, 40-49, 50-59, 60 years and older). Dental pulp volume of five categories of teeth(upper canines, left upper central incisors, left upper first molars, lower left first premolars, first molars) were analyzed using Romexis® 5.3.3.5 software for each patient. There was a reduction in the pulp volume of upper right and left canine with age. The Pulp volume was lowest in people aged 60 years and over. Linear regression analysis of the pulp volume and chronological age showed a coefficient of determination of 30%, suggesting a weak correlation. A weak correlation between dental pulp and age is derived. But, a robust large homogenous sample of teeth in future for different age groups may establish a reliable regression equation.

Resumen La estimación de la edad dental en personas vivas y cadáveres es muy importante para la Odontología Forense, sobre todo en casos de identificación en investigaciones legales y sociales. El objetivo del estudio fue estimación de la edad dental mediante la medición del volumen pulpar de imágenes dentales en tomografía computarizada de haz cónico (TCHC) de pacientes peruanos. Fueron analizadas 231 TCHC de pacientes entre 12 a 60 años a más. (Mujeres (134), hombres (97)) se dividieron en seis grupos de edad (12-19, 20-29, 30-39, 40-49, 50-59, 60 años a más). El análisis volumétrico de la pulpa dental se realizó en un total de 1155 dientes (caninos superiores, incisivos centrales superiores izquierdos, primeros molares superiores izquierdos y primeros premolares inferiores izquierdos), mediante el software Romexis® 5.3.3.5. El análisis de regresión lineal mostró un coeficiente de determinación del 30% que sugiere una correlación débil entre la relación del volumen pulpar de los dientes y la edad. El volumen pulpar de los caninos superiores derecho e izquierdo disminuyó a medida que aumentaba la edad y el volumen pulpar en dientes de personas de 60 años a más fue el más bajo. Sin embargo, se pueden proponer estudios futuros para incluir una gran muestra homogénea de dientes en diferentes categorías y grupos de edad para confirmar la correlación y establecer una ecuación de regresión confiable.

Clasificación alternativa para terceros molares / Alternate classification for third molars

Resumen Introducción En el presente artículo se describen las diferentes clasificaciones de terceros molares retenidos y se recomienda una nueva clasificación que permite predecir la dificultad para la remoción respectiva. Objetivo Lo anterior tiene la finalidad servir de guía para que los estudiantes o profesionales en Odontología utilicen como clasificador el grado de dificultad de terceras molares, el cual se constituiría en un instrumento de medición del tiempo necesario para remover la pieza dental, los pasos necesarios para dicha remoción y la morbilidad relacionada.

Abstract Introduction Different literaly classifications of impacted wisdom teeth will be shown in adddition to a new categorization wich predicts their removal difficulty. Aim The goal of the above statement is to be used as a guide for students and/or collegues to classify the degree of difficulty as a tool to measure the needed time to extract the tooth and the necessary steps to remove it and the related morbility.

Quiste dentígero gigante en seno maxilar: Caso Clínico / Giant dentigerous cyst in the maxillary sinus: A Case Report

El proceso biológico de la odontogénesis es complejo, en ella participan mecanismos moleculares y celulares orientados a formar las estructuras dentarias, la alteración de estos mecanismos pueden originar los quistes dentígeros o foliculares. Estas patologías son cavidades anormales recubiertas por epitelio y con contenido líquido o semilíquido, rodeados generalmente de una capa de tejido conectivo; siempre asociados a la corona de dientes incluidos, son asintomáticos y de evolución lenta, descubiertas radiográficamente como una imagen unilocular y radiolúcidos, los de gran tamaño son infrecuentes, el tratamiento consiste en remoción quirúrgica completa.

The biological process of odontogenesis is complex, where molecular and cellular mechanisms participate at forming dental structures. The alteration of these mechanisms can cause dentigerous or follicular cysts, which are pathologies with abnormal cavities lined by epithelium and with liquid or semi-liquid content, usually surrounded by a layer of connective tissue; always associated with the crown of included teeth, they are asymptomatic and of slow evolution, discovered radiographically as a unilocular image and radiolucent. The large ones are infrequent and their treatment consists of complete surgical removal.

Natal teeth in premature neonates, products of twin gestation. A case report

Se presenta el caso de 02 recién nacidas gemelares, pre-términos tardíos, producto de gestación monocoriónica - biamniótica con presencia de dientes natales, los cuáles requirieron evaluación odontológica para definir la mejor conducta a seguir y con ello evitar riesgos o desenlaces fatales como la aspiración hacia bronquios. La evaluación evidenció escasa movilidad de piezas dentarias en ambos casos, por lo que se recomendó mantener los dientes; del mismo modo, se dio consejería a los padres sobre la higiene y cuidado de la salud bucal de sus hijas con control ambulatorio a los 3 meses.

We present the case of 2 twin newborns, late preterm, who were a product of monochorionic - diamniotic gestation and presented with natal teeth, which required a dental evaluation to define the best management strategy and thereby avoid risks or fatal outcomes such as bronchial aspiration. The evaluation showed little mobility of teeth in both cases, so it was recommended to keep the teeth. The parents were counseled on proper oral health care and hygiene for their daughters and scheduled for an outpatient follow-up at 3 months.

A Importância dos Métodos de Determinação das Idades Esquelética e Dentária na Ortodontia e Odontopediatria ­ uma Revisão de Literatura / The Importance of Methods for Determination of Squeletal and Dental Age in Orthodontics and Pediatric Dentistry ­ a Literature Review

O estágio de desenvolvimento humano é intimamente relacionado à sua maturidade óssea ou dentária, sendo essencial para a escolha do tratamento de alterações dentofaciais em crianças e adolescentes por ortodontistas e odontopediatras. Existem diversos indicadores biológicos para determinar a maturação do indivíduo, como a idade cronológica e as alterações hormonais, porém esses indicadores podem sofrer interferências. Visando uma determinação de desenvolvimento e dos picos de crescimento mais precisa, para um melhor diagnóstico e plano de tratamento, foram desenvolvidos diversos métodos para determinar a idade esquelética e a idade dentária, sendo estes a avaliação da maturação carpal, da morfologia das vértebras cervicais, da fusão óssea da sincondrose esfeno-occipital e da sutura palatina mediana, bem como dos estágios da calcificação dentária. A avaliação das radiografias de mão e punho é o padrão ouro da predição da idade esquelética, e sua correlação com outros métodos já é evidente. Sendo assim, é possível utilizar a avaliação das vértebras cervicais e das idades dentárias de Nolla e Demirjian.

The stage of human development is closely related to bone or dental maturity, being essential for the choice of treatment for dentofacial changes in children and adolescents by orthodontists and pediatric dentists. There are several biological indicators to determine an individual's maturation, such as chronological age and hormonal changes, but these indicators can suffer interference. Aiming at a more accurate determination of development and growth peaks, for a better diagnosis and treatment plan, several methods have been developed to determine skeletal age and dental age, these being the assessment of carpal maturation, the morphology of the cervical vertebrae, bone fusion of the spheno-occipital synchondrosis and the median palatal suture, as well as the stages of dental calcification. The evaluation of hand and wrist radiographs is the gold standard for predicting skeletal age, and its correlation with other methods is already evident. Therefore, it is possible to use the assessment of cervical vertebrae and dental ages by Nolla and Demirjian.

Brote dentario precoz. Un acercamiento a la realidad

Introducción: Las tendencias seglares influyen en el crecimiento y desarrollo general del individuo. El brote dentario no escapa a esta realidad. Existen variables que pueden retardarlo o acelerarlo, dentro de las que se encuentran el sexo y el color de la piel. Objetivos: Determinar la cronología y el orden de brote de los dientes permanentes en niños y adolescentes. Métodos: Se realizó un estudio transversal descriptivo desde mayo de 2017 a noviembre de 2020. El universo constituido por 21383 niños y adolescentes entre 5 y 13 años de edad, de la provincia Holguín, Cuba, que no presentaban pérdida prematura de dientes temporales o extracciones de dientes permanentes, ni enfermedades sistémicas que influyen en el crecimiento y desarrollo. En el procesamiento estadístico se utilizaron las medidas de resúmenes para las variables cuantitativas y el test de comparación de las medias. Resultados: La edad de brote de todos los dientes permanentes resultó adelantada en comparación con las tablas para su valoración clínica. El primer diente en brotar fue el primer molar superior, entre los 5,66 años, y el último el segundo molar maxilar, entre los 10,38 años. Al comparar las medias de brote de los dientes permanentes según el sexo, hubo diferencias altamente significativas en la arcada superior: primer premolar (p = 0,000), arcada inferior: canino (p = 0,009), primer premolar (p = 0,000) y segundo molar (p = 0,012). Se encontraron diferencias altamente significativas entre las medias de brote para el color de la piel en el maxilar: incisivo central (p = 0,004), incisivo lateral (p = 0,000), canino (p = 0,002), mandíbula: incisivo central (p = 0,000), incisivo lateral (p = 0,000) y segundo premolar (p = 0,000). Conclusiones: La cronología de brote de todos los dientes permanentes resultó adelantada. Los dientes permanentes siguieron la secuencia de brote, tal como describe Mayoral. Se encontraron diferencias al comparar las medias de brote según el sexo y color de la piel.

Introduction: Secular tendencies influence the overall growth and development of the individual. Tooth eruption does not escape this reality. There are variables that can delay or accelerate it, among which are sex and skin color. Objectives: To determine the chronology and order of eruption of permanent teeth in children and adolescents. Methods: A descriptive cross-sectional study was conducted from May 2017 to November 2020. The universe constituted by 21383 children and adolescents between 5 and 13 years of age, from Holguín province, Cuba, who did not present premature loss of primary teeth or extractions of permanent teeth, nor systemic diseases that influence growth and development. Statistical processing used summary measures for quantitative variables and the comparison test of the average values. Results: The age of teething of all permanent teeth was advanced in comparison with the tables for clinical assessment. The first tooth was the upper first molar at 5.66 years of age and the last tooth was the maxillary second molar at 10.38 years of age. When comparing the teething averages of the permanent teeth according to gender, there were highly significant differences in the upper arch: first premolar (p = 0.000), lower arch: canine (p = 0.009), first premolar (p = 0.000) and second molar (p = 0.012). Highly significant differences were found between bud means for skin color in maxilla: central incisor (p = 0.004), lateral incisor (p = 0.000), canine (p = 0.002), mandible: central incisor (p = 0.000), lateral incisor (p = 0.000) and second premolar (p = 0.000). Conclusions: The teething chronology of all permanent teeth resulted advanced. The permanent teeth followed the teething sequence as described by Mayoral. Differences were found when comparing the teething averages according to gender and skin color.

Tercer molar heterotópico, etiología y manejo quirúrgico / Heterotopic third molar, etiology and surgical management

Los terceros molares heterotópicos son dientes que se encuentran incluidos en los maxilares y la mandíbula distantes a su sitio de erupción habitual. Su etiología no está bien definida y existen diversas teorías. Estos dientes pueden aparecer en diferentes zonas de las estructuras óseas, teniendo predilección por la mandíbula. Suelen aparecer entre la segunda y la séptima década de la vida, la mayoría de los casos son hallazgos imagenológicos en la consulta odontológica. El tercer molar mandibular es el diente que presenta heterotopía con mayor frecuencia, siendo su localización habitual en rama mandibular y en la región subcondílea. El quiste dentígero es la patología asociada más común. Presentamos un caso de tercer molar heterotópico en rama mandibular derecha de larga evolución, relacionado a un quiste dentígero, el cual se manejó bajo anestesia regional. Se describe la etiología, técnica quirúrgica y consideraciones especiales relacionados con los dientes heterotópicos (AU)

Heterotopic third molars are teeth that are embedded in the maxilla and mandible, remote from their usual eruption site. Its etiology is not well defined and there are various theories at the moment. These teeth can appear in different areas of the bone's structures, having a predilection for the jaw. They usually appear between the second and seventh decade of life, and in most cases are imaging findings. The mandibular third molar is the tooth with the most frequent heterotopia, being its usual location in the mandibular branch and in the subcondylar region. The dentigerous cyst is the most common associated pathology. We present a case of a long evolution heterotopic third molar in the right mandibular branch, related to a dentigerous cyst which was managed under local anesthesia. The etiology, surgical technique and special considerations related to heterotopic teeth are described (AU)

The Effect of Nicotine Lozenge Over Teeth Bleaching During Cigarette's Addiction Treatment

The aim of this study was to evaluate the effect of nicotine lozenge on teeth staining with/without bleaching in animal model study. A total of 15 Wistar rats were exposed in an acrylic container to 10 cigarettes smoke three times a day for 8 minutes per time, and sacrificed after 60 days. A total of 30 incisor teeth were treated (n=10) as the following: Group-1: in-office bleaching, at-home bleaching and immersion in artificial saliva; group-2: in-office bleaching, at - home bleaching and immersion in nicotine lozenge solution and in artificial saliva; group-3: immersion in nicotine lozenge solution and in artificial. The specimens of all groups were photographed using a stereomicroscope at T1) immediately after the extraction and before any treatment; T2) after one month of the treatment; and T3) after two months of the treatment. Four equidistant points of each specimen were analyzed using CMYK shade guide. The data were analyzed one-way ANOVA test followed by Tukey test for multiple comparisons with (a ≤ 0.05). In group-1, there was a significant difference of the color saturation of specimens between T1 and T2, and between T1 and T3 readings (P<0.0001). In group-2, there was a significant difference of the color saturation of specimens between T1 and T2, between T2 and T3 readings (P<0.0001). In group-3, there was a significant difference of the color saturation of specimens between T1 and T2, and between T1 and T3 readings (P<0.0001). The usage of nicotine lozenge promotes teeth lighting with/without bleaching.

El objetivo de este estudio fue evaluar el efecto de comprimidos de nicotina sobre la tinción de los dientes con/sin blanqueamiento en un estudio de modelo animal. Un total de 15 ratas Wistar fueron expuestas en un recipiente acrílico al humo de 10 cigarrillos tres veces al día durante 8 minutos por vez, y sacrificadas después de 60 días. Se trataron un total de 30 dientes incisivos (n=10) de la siguiente manera: Grupo-1: blanqueamiento en consultorio, blanqueamiento en casa e inmersión en saliva artificial; grupo-2: blanqueamiento en consultorio, blanqueamiento en casa e inmersión en solución de comprimidos de nicotina y en saliva artificial; grupo-3: inmersión en solución de nicotina en comprimidos y en artificial. Los especímenes de todos los grupos fueron fotografiados utilizando un microscopio estereoscópico en T1) inmediatamente después de la extracción y antes de cualquier tratamiento; T2) después de un mes del tratamiento; y T3) a los dos meses del tratamiento. Se analizaron cuatro puntos equidistantes de cada espécimen utilizando la guía de colores CMYK. Los datos se analizaron con la prueba ANOVA unidireccional seguida de la prueba de Tukey para comparaciones múltiples con (a ≤ 0,05). En el grupo 1, hubo una diferencia significativa de la saturación de color de las muestras entre T1 y T2, y entre las lecturas T1 y T3 (P<0,0001). En el grupo 2, hubo una diferencia significativa de la saturación de color de las muestras entre T1 y T2, entre las lecturas de T2 y T3 (P<0.0001). En el grupo 3, hubo unadiferencia significativa de la saturación de color de las muestras entre T1 y T2, y entre las lecturas T1 y T3 (P<0,0001). El uso de comprimidos de nicotina promueve la iluminación de los dientes con/sin blanqueamiento.

Application of interpenetrating polymer network enamel-like teeth in the dental practice teaching of crown preparations / 中华医学教育探索杂志

Objective:To explore a type of teaching teeth that can highly simulate natural teeth, and to investigate its application in the practice teaching of crown preparations.Methods:A total of 44 senior students majoring in stomatology Fourth Military Medical University were selected, and each student received the training of crown preparations using interpenetrating polymer network (IPN) enamel-like teaching teeth, extracted natural teeth, and traditional composite resin teeth. Operation assessment was performed, and the operation time of each crown preparation was recorded. According to the requirements for crown preparations, scores were determined from the five aspects of axial converging, space for repair, line angle, shoulder quality, and posture, with 10 points for each aspect and 50 points in total, and the total score was calculated. A questionnaire survey on IPN enamel-like teeth was performed for each student after assessment, and SPSS 23.0 was used to perform the least significant difference t-test and the Tambane's T2 test. Results:There was no significant difference in total assessment score between the IPN enamel-like teeth group and the natural teeth group (37.15±1.17 vs. 37.20±1.20, P>0.05), and both groups had a significantly higher total score than the resin teeth group (31.53±1.41) ( P<0.05). The IPN enamel-like teeth group and the natural teeth group had significantly higher scores than the traditional composite resin teeth group in terms of axial converging, space for repair, and shoulder quality ( P<0.05). The questionnaire survey of the students showed a relatively high score of 3.7-4.9 for each item. Conclusion:Compared with traditional composite resin teeth, IPN enamel-like teeth can more comprehensively and effectively simulate the operation and experience of natural teeth for crown preparations and thus have potential advantages in the practice teaching of crown preparations.

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.

Measurement of buccolingual inclination of posterior teeth and the curve of Wilson in patients with different sagittal skeletal patterns using cone-beam computed tomography / 口腔疾病防治

Objective@# To study the buccolingual inclination of posterior premolars and molars and the curve of Wilson in patients with different sagittal skeletal patterns, to explore the compensation mechanism of horizontal inclination of posterior teeth in patients with different sagittal skeletal patterns and to provide a reference for the control of posterior tooth inclination in the treatment of bone malocclusion.@*Methods@#This study was reviewed and approved by the Ethics Committee, and informed consent was obtained from the patients. Ninety CBCT scans of adults and ninety scans of adolescents before orthodontic treatment were evaluated in this cross-sectional study. There were 30 skeletal Class I, Class Ⅱ, and Class Ⅲ patients in the adult group and adolescent group. The inclination angles of posterior teeth and the curve of Wilson of first and second molars were measured, and data were analyzed between adolescents and adults with different sagittal skeletal patterns.@*Results @#Compared with skeletal Class Ⅰ adult patients, the upper posterior molar inclination of skeletal Class Ⅱ patients was significantly lower, and the lower posterior molar inclination was significantly higher. Compared with skeletal ClassⅠ adult patients, the upper posterior molar inclination of skeletal Class Ⅲ adult patients was higher, and the lower posterior molar inclination was significantly lower. The Wilson curve of the second molar in skeletal Class Ⅱ adult patients was significantly higher than that in the other groups. Compared with skeletal ClassⅠ adolescent patients, skeletal Class Ⅲ adolescent patients had a significantly higher upper posterior molar inclination; however, no difference was found between the inclination of the posterior teeth between skeletal Class Ⅰ, Class Ⅱ and Class Ⅲ adolescent patients. Comparing adolescent and adult samples, in skeletal Class Ⅱ patients, adults showed more lingual inclination than adolescents in the upper posterior teeth and less lingual inclination in the lower posterior teeth except for the mandibular first molar. Comparing adolescent and adult samples, in skeletal Class Ⅲ patients, adults showed more lingual inclination than adolescents in the lower posterior teeth except for the mandibular second molars and showed no difference in the upper posterior teeth.@*Conclusions@#The inclination of the posterior teeth and the curve of Wilson show significant differences between the three sagittal skeletal patterns. Compared with those of skeletal Class Ⅰ patients, the posterior teeth of skeletal Class Ⅱ patients show more lingual inclination in the upper arch and less lingual inclination in the lower arch. Meanwhile, posterior teeth of skeletal Class Ⅲ patients show more lingual inclination in the lower arch and maintain the inclination in the upper arch.

Clinical application of a digital positioning guide template during the extraction of maxillary wholly impacted supernumerary teeth / 口腔疾病防治

Objective@#To evaluate the clinical efficacy of positioning guide templates for maxillary wholly impacted supernumerary teeth to provide technological solutions for clinical applications. @*Methods @#After approval by the hospital ethics committee and informed consent given by the patients. Data from 136 patients with maxillary wholly impacted supernumerary teeth from January 2016 to April 2022 were analyzed retrospectively. The patients were divided into two groups according to the usage of the positioning guide template. The experimental group included patients using the positioning guide template (71 cases), and the control group did not use the positioning guide template (65 cases). The operation time and complications were statistically analyzed to evaluate the clinical efficacy after surgery. @*Results @# All operations were successfully completed. The average operation time in the experimental group was (21.5 ± 3.4) min, significantly shorter than that in the control group (27.2 ± 4.9) min. There were statistically significant differences between the experimental and control groups (t = 7.599, P<0.001). One week after the operation, there were no complications in the experimental group, and there were 2 cases of adjacent tooth injury and 3 cases of gingival numbness in the control group.@* Conclusion @# A digital positioning guide template can effectively shorten the time of maxillary wholly impacted supernumerary teeth extraction and is an effective means to assist clinical maxillary wholly impacted supernumerary teeth extraction.

Application of soft tissue augmentation in labial contour aesthetics of anterior dental implants / 口腔疾病防治

@#After tooth extraction, labial contour collapses due to inevitable physiologic bone remodeling. To achieve optimal outcomes for pink esthetic treatment at anterior implant sites, bone or soft tissue augmentation has been advocated to maintain or reconstruct the labial tissue contour. When choosing soft tissue augmentation for esthetic restoration, it is necessary to strictly grasp the indications for surgery. Soft tissue augmentation to maintain or reconstruct the labial tissue contour could be considered in patients with healthy soft tissue and no bone defects or only mild horizontal bone defects. In immediate, early and late implant placement, the timing of soft tissue augmentation may vary. In immediate implantation, the labial bone plate is intact, so it is highly recommended to simultaneously manage soft tissue during implant placement. However, patients may have large bone defects with early or late implant placement. The risk of augmenting bone and soft tissue simultaneously is likely too high, and bone augmentation surgery is often performed at the first stage while soft tissue augmentation surgery is performed at the second stage. Therefore, soft tissue surgery is often carried out simultaneously with abutment connection. Currently, soft tissue augmentation is achieved mostly with adjacent autologous soft tissue grafts, such as free gingival grafts, subepithelial connective tissue grafts or pedicle palatal flaps, which are often accompanied by a second surgical area. The replacement of autogenous soft tissue grafting with new biological materials will become an inevitable trend. In this article, we analyze and summarize the indications, timing and different methods of soft tissue augmentation to maintain and reconstruct the labial contour.

Combined micro-apical surgery and vital pulp therapy in mandibular second molars with external root resorption caused by impacted teeth / 华西口腔医学杂志

OBJECTIVES@#This study aimed to establish a new treatment of the mandibular second molars with external root resorption caused by impacted teeth to preserve the affected teeth and their vital pulps.@*METHODS@#For mandibular second molars clinically diagnosed as external root resorption caused by impacted teeth, debridement and removal of the root at the resorption site via micro-apical surgery and direct capping of the pulp with bioactive material on the surface of the root amputation via vital pulp therapy were performed immediately after the impacted teeth were extracted.@*RESULTS@#The external root resorption of the affected tooth was ceased. It was asymptomatic with intact crown, normal pulp, periapical alveolar bone reconstruction, normal periodontal ligament, continuous bone sclerosis, and no periapical translucency in radiographic examination at the 1-year postoperative follow-up, thus showing good prognosis.@*CONCLUSIONS@#Simultaneous combination of micro-apical surgery and vital pulp therapy after extraction of impacted teeth could successfully preserve mandibular second molars with ERR caused by impacted teeth and their vital pulps.

Analysis of congenital deciduous teeth absence and its permanent teeth phenotype / 华西口腔医学杂志

OBJECTIVES@#This study aimed to investigate the clinical characteristics of congenital deciduous teeth absence and its permanent teeth performance type by using panoramic radiographs.@*METHODS@#A total of 15 749 panora-mic radiographs of 3-6-year-old children with deciduous dentition were collected from January 2020 to December 2021. The incidence of congenital deciduous teeth absence was observed, and the abnormality of permanent teeth was recor-ded. SPSS 24.0 software was used for statistical analysis.@*RESULTS@#The incidence of congenital deciduous teeth absence was 2.54% (400/15 749), which was found in 217 girls and 183 boys, and the difference between the genders was statistically significant (P=0.003). The absence of one and two deciduous teeth accounted for 99.75% (399/400) of the subjects. In addition, 92.63% (490/529) of mandibular deciduous lateral incisor was congenitally absent, 44.80% (237/529) of deciduous teeth was absent in the left jaw, and less than 55.20% (292/529) was absent in the right; the difference between them was statistically significant (P=0.017). The absence of 96.41% (510/529) deciduous teeth in the mandibular was significantly more than that of 3.59% (19/529) in the maxillary, and the difference between was statistically significant (P=0.000). Furthermore, 68.00% (272/400) and 32.00% (128/400) of deciduous teeth were absent in unilateral and bilateral, respectively, and the difference was statistically significant (P=0.000). Four types of congenital deciduous teeth absence with permanent teeth were observed as follows: 1) 73.91% (391/529) of permanent teeth was absent; 2) 20.60% (109/529) of permanent teeth was not absent; 3) the number of fused permanent teeth accounted for 4.91% (26/529); 4) the number of supernumerary teeth was 0.57% (3/529).@*CONCLUSIONS@#Although the absence of congenital deciduous teeth is less common than that of permanent teeth, it affects deciduous and permanent teeth to some extent. Dentists should pay attention to trace and observe whether abnormalities are present in the permanent teeth and take timely measures to maintain children's oral health.

One-year clinical observation of the effect of internal bleaching on pulpless discolored teeth / 华西口腔医学杂志

OBJECTIVES@#This study aimed to observe the color rebound and rebound rates of non-pulp discolored teeth within 1 year after routine internal bleaching to guide clinical practice and prompt prognosis.@*METHODS@#In this work, the efficacy of bleaching was observed in 20 patients. The color of discolored teeth was measured by using a computerized colorimeter before bleaching; immediately after bleaching; and at the 1st, 3rd, 6th, 9th, and 12th months after bleaching. The L*, a*, and b* values of the color of cervical, mesial, and incisal parts of the teeth were obtained, and the color change amounts ΔE*, ΔL*, Δa*, and Δb* were calculated. The overall rebound rate (P*) and the color rebound velocity (V*) were also analyzed over time.@*RESULTS@#In 20 patients following treatment, the average ΔE* of tooth color change was 14.99. After bleaching, the neck and middle of the teeth ΔE* and ΔL* decreased in the 1st, 3rd, 6th, 9th, and 12th months, and the differences were statistically significant. Meanwhile, from the 9th month after bleaching, the rebound speed was lower than that in the 1st month, and the difference was statistically significant. The incisal end of the tooth ΔE* and ΔL* decreased in the 6th, 9th, and 12th months after bleaching, and the differences were statistically significant. No significant difference was found in the rebound speed between time points. However, this rate settled after the 9th month, with an average color rebound rate of 30.11% in 20 patients.@*CONCLUSIONS@#The results indicated that internal bleaching could cause a noticeable color change on pulpless teeth. The color rebound after bleaching was mainly caused by lightness (L*), which gradually decreased with time, and it was slightly related to a* and b*. The color of the teeth after internal bleaching rebounded to a certain extent with time, but the color rebound speed became stable from the 9th month. Clinically, secondary internal bleaching can be considered at this time according to whether the colors of the affected tooth and the adjacent tooth are coordinated and depending on the patient's needs.

The influence of the retention feature in artificial teeth on its attachment to the thermoplastic resin denture base / Influência da forma de retenção em dentes artificiais de resina acrílica na fixação na base de prótese termoplástica

Objective: Teeth play a crucial role in masticatory efficiency and esthetic harmony making rehabilitation of partially edentulous patients a challenge because of the limitations of conventional removable partial dentures. As a therapeutic alternative, thermoplastic polymers are used in current dental practice either for practical processing purposes or aesthetics. However, it is recognized that the bond between acrylic resin artificial teeth and thermoplastic polymers has no chemical interaction, and depends on retentive features added to the teeth. This study analyzed the efficacy of two retentive forms of features through compressive strength test and as a secondary outcome, fracture and displacement resistance test. Material and Methods: Three groups of samples each with 14 sets of acrylic teeth were compared when two retentive features, single hole and groove retention, and a control group with teeth without any specific form. The experimental unit consisted of six maxillary anterior teeth, positioned in a linear pattern into a polypropylene block, where each tooth was submitted to a static load until its removal, on a universal testing machine. Results: Those specimens with a groove retention presented larger resistance to displacement when compared to the other groups (p <0.05). This was emphasized by the fracture of the tooth tested, with part of the cervical portion remaining embed in the base, and not its displacement as with (or without) the retentive feature. Conclusion: In this study, the type of retention influenced significantly to a better retention considering teeth and thermoplastic polymer base. The data in this study indicates that a groove placed on the artificial tooth offers significantly better retention efficacy to the point where the displacement was only possible after its fracture (AU)

Objetivo: Os dentes são um fator essencial na eficiência mastigatória. A harmonia estética e a reabilitação dos indivíduos parcialmente dentados tornam-se um desafio, frente às limitações das próteses parciais removíveis convencionais. Como uma alternativa terapêutica, os polímeros termoplásticos são utilizados na odontologia contemporânea, tanto para o seu processamento prático como seu apelo estético. Entretanto, pouco se sabe a respeito da união entre a resina acrílica de dentes artificiais e resinas termoplásticas, assim como a influência dos mecanismos de retenção, uma vez que não há interação química entre eles. O objetivo deste estudo foi analisar duas formas de retenção de dentes de resina acrílica a bases de prótese de material termoplástico, por força compressiva e como desfecho secundário, teste de resistência a fratura e deslocamento dos dentes artificiais. Material e Métodos: O presente estudo analisou dois tipos diferentes de retenções: uma cavidade com único ponto e uma canaleta de mesial a distal; e como grupo controle, dentes colocados sem qualquer recurso específico. A unidade experimental consistiu de seis dentes superiores anteriores, posicionados em linha em um bloco de polipropileno. Em cada dente artificial foi aplicada força até a sua remoção, em uma máquina universal de ensaios. Resultados: Os resultados mostraram que a retenção com canaleta apresentou maior força de deslocamento, quando comparado com os outros grupos (p <0,05). Tal fato foi evidenciado pelo teste de fratura e deslocamento, no qual parte da porção cervical do dente artificial permaneceu unida à base, não ocorrendo o deslocamento com (ou sem) a retenção. Conclusão: Neste estudo, o tipo de retenção influenciou de forma significante a retenção de dentes artificiais de resina acrílica a bases de prótese termoplásticas. Os dados deste estudo indicam que a confecção da retenção em canaleta nos dentes artificiais oferece significante aumento na eficiência da retenção, ao ponto em que o deslocamento do dente ocorreu somente após sua fratura (AU).

Performance of resin composite restorations placed in high caries risk children: a clinical retrospective study

Background: Resin composite has been usually used for restoring primary teeth. Nevertheless, there is a lack of supporting clinical data regarding the survival of resin composite restorations and risk factors that may dictate the service time of the treatment in children. Aim: To evaluate the survival and factors associated with composite resin restoration failure in high caries risk children treated under risk-factor management clinical protocol for dental caries prior to restorative therapy. Design: A total of 230 restorations in primary teeth from records of 48 patients were included in the study. Restoration longevity, up to 3-year follow-up, was assessed using the Kaplan-Meier survival test. Multivariate Cox regression analysis with shared frailty was used to evaluate the factors associated with failures (p<0.05). Results: Mean survival time was 2.7 -year (95 %CI: 0.75-0.87). Restoration survival reached 82.5 % up to 3-year evaluation, with an overall annual failure rate of 6.2 %. The unadjusted model showed restorations performed in children with dmf-t greater than 10 had more restoration failure risk (HR 5.59, 95 % CI 1.03-30.34; p=0.04) However, this association lost significance in the adjusted analysis (p=0.08). Conclusions: Composite resin restorations in primary teeth presented satisfactory survival after 3-year follow-up

Antecedentes: El composite de resina se ha utilizado habitualmente para restaurar dientes primarios. Sin embargo, se carece de datos clínicos de apoyo sobre la supervivencia de las restauraciones de resina compuesta y los factores de riesgo que pueden dictar el tiempo de servicio del tratamiento en los niños. Objetivo: Evaluar la supervivencia y los factores asociados al fracaso de las restauraciones de resina compuesta en niños con alto riesgo de caries tratados con un protocolo clínico de gestión de factores de riesgo de caries dental antes del tratamiento restaurador. Diseño: Se incluyeron en el estudio un total de 230 restauraciones en dientes primarios de registros de 48 pacientes. La longevidad de las restauraciones, hasta los 3 años de seguimiento, se evaluó mediante la prueba de supervivencia de Kaplan-Meier. Se utilizó un análisis multivariante de regresión de Cox con fragilidad compartida para evaluar los factores asociados a los fracasos (p<0,05). Resultados: El tiempo medio de supervivencia fue de 2,7 -años (IC95%: 0,75-0,87). La supervivencia de la restauración alcanzó el 82,5 % hasta la evaluación a los 3 años, con una tasa global anual de fracasos del 6,2 %. El modelo no ajustado mostró que las restauraciones realizadas en niños con dmf-t superior a 10 tenían más riesgo de fracaso de la restauración (HR 5,59; IC 95 %: 1,03-30,34; p=0,04). Sin embargo, esta asociación perdió significación en el análisis ajustado (p=0,08). Conclusiones: Las restauraciones de resina compuesta en dientes primarios presentaron una supervivencia satisfactoria tras un seguimiento de 3 años.