Cone-beam computed tomography study of root length of maxillary and mandibular anterior teeth and central incisor crown-root morphology in high-angle Class Ⅱ open bite patients / 口腔疾病防治

Objective@#This study aimed to explore the root length of maxillary and mandibular anterior teeth and central incisor crown-root morphology in patients with high-angle skeletal Class Ⅱ open bite, aiming to provide a reference for clinical treatment.@*. Methods@#This study was reviewed and approved by the Ethics Committee, and informed consent was obtained from the patients. CBCT images of eighty-one untreated patients (40 anterior open bite patients and 41 normal overbite patients) with high-angle skeletal Class Ⅱ malocclusion were selected before treatment. Dolphin software was used to study the root length of maxillary and mandibular anterior teeth and central incisor crown-root morphology, and the differences between the two groups were analyzed.@*Results@#There was no statistical significance in the root length of maxillary lateral incisor and canine between the open bite group and the normal overbite group, significant differences were found in the root length of maxillary central incisor （11.12 ± 1.37） mm、mandibular central incisor（10.15 ± 1.09）mm, mandibular lateral incisor（11.27 ± 1.15）mm and mandibular canine（12.81 ± 1.48）mm between the open bite group and the normal overbite group（P<0.05）. On the other hand, the two groups were significantly different in crown-root morphology of the maxillary central incisor (1.10° ± 3.62° vs. 4.53° ± 2.30°, P<0.01) but not in the mandibular central incisor.@*Conclusion@#The root length of the maxillary central incisor, mandibular central incisor, mandibular lateral incisor, mandibular canine in high-angle Class Ⅱ open bite patients is shorter than that in high-angle Class Ⅱ normal overbite patients, and the long axis of the crown of the maxillary central incisor in high-angle Class Ⅱ open bite patients obviously deviates toward the labial side relative to the long axis of the root. The crown-root angle is smaller, which is beneficial to torque control or adduction movement of the anterior teeth in high-angle Class Ⅱ open bite patients.

Evaluation of condylar position in patients with malocclusion and changes in condylar position before and after orthodontic treatment using cone beam computed tomography / 口腔疾病防治

@#The functional health and stability of the oral and maxillofacial system is one of the basic goals of orthodontic treatment. Currently, it is believed that, in general, the condyle is located in the center of the joint fossa when the mandible is in an intercuspal position (ICP) in healthy normal people. At this time, the function of the temporomandibular joint (TMJ) is stable. Due to orthodontic tooth movement and subsequent occlusal changes, patients with malocclusion may experience related remodeling of the temporomandibular joint, especially changes in the position of the condyle. The position of the mandibular condyle is traditionally evaluated using a condylar position indicator. However, this method lacks consistency in obtaining condylar position changes. In recent years, in the clinical application of orthodontic treatment, cone beam computed tomography (CBCT) has become the first choice for examination. CBCT can accurately measure the interarticular space and determine changes in condylar position. This article reviews the CBCT assessment of condylar position and related research on condylar position changes in patients with malocclusion before and after orthodontic treatment. The literature review results indicate that there are differences in the condylar position of patients with different malocclusions, and the condylar position may also change before and after orthodontic treatment. With a lower radiation dose, CBCT has higher accuracy in evaluating the condylar position in patients with malocclusion who undergo orthodontic treatment, thus promoting further study of the mechanism of condylar position changes in patients with malocclusion in the future and providing more accurate and personalized guidance for patient treatment.

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.

Research progress on invasive cervical resorption / 口腔疾病防治

@#Tooth absorption can be divided into physiological absorption and pathological absorption. Root absorption of mature deciduous teeth is physiological absorption. Pathological absorption includes internal absorption and external absorption. Internal absorption, also known as intramedullary absorption, includes inflammatory absorption and alternative absorption. External tooth absorption originates from the outer surface of the root or the neck of the tooth and can be divided into inflammatory absorption, alternative absorption, pressure resorption and invasive cervical resorption. Invasive cervical resorption (ICR) is pathological damage caused by many factors, which usually begins in the cemento-enamel junction and extends peripherally or horizontally in the dentin. It hardly invades the pulp. Orthodontic devices, trauma, bleaching, systemic diseases, and the use of certain medications can all lead to invasive cervical resorption. The clinical manifestations of ICR are usually asymptomatic or not obvious, and most of which are found in imaging examinations. Because caries and internal absorption are often misdiagnosed through plain apical radiography, cone beam computed tomography (CBCT) can help to better understand the situation of invasive cervical resorption. Because the pathogenesis and etiology of invasive cervical resorption are not fully understood, clinical negligence and inadequate treatment of invasive cervical resorption can even cause unnecessary tooth loss. This article reviews the latest research progress on the histopathologic features, pathogenic mechanism, susceptibility factors, diagnosis and treatment of ICR, with special emphasis on susceptibility factors and their mechanisms.

Epidermoid cyst in the right mandible: a case report and literature review / 口腔疾病防治

Objective@#To discuss the possible etiology, pathogenesis, clinical features, diagnosis and treatment of epidermoid cysts of the jaw and to provide a reference for clinical diagnosis and treatment.@*Methods@#A case of an epidermoid cyst in the right mandible with retained deciduous teeth and succedaneous impacted teeth was reviewed and analyzed in combination with the relevant literature.@*Results@#A patient presented with a mass in the right mandible that had persisted for 1 month after being found at imaging examination. Tooth 83 was retained, and tooth 43 was unerupted. Swelling was characterized by no obvious tenderness, fluctuation, or table tennis sensation and was observed in the lingual alveoli of teeth 83, 44, and 45. Imaging revealed a low-density shadow in the apex of teeth 83, 44, 45, and 46, approximately 1.9 cm × 2.6 cm × 1.6 cm in size, which wrapped around the dental crown of tooth 43. Preliminary diagnoses were as follows: right mandibular mass thought to be a dentigerous cyst; impacted tooth 43; and retained primary tooth 83. The mass in the right mandible was removed, and teeth 43 and 83 were extracted under intravenous and inhalation anesthesia. During the operation, the mass was observed to have a thin cyst wall and contained bean-like residue. Histopathological examination indicated an epidermoid cyst in the right mandible. At the 1-week follow-up examination, the patient reported no discomfort, and the surgical area showed good recovery. According to the literature, epidermoid cysts are benign cysts originating from ectopic ectodermal tissue that can occur throughout the body but rarely in the oral cavity and are even extremely rarer in the jaw. Epidermoid cysts of the jaw, which have no specific clinical manifestations, can be confused with odontogenic cysts such as dentigerous cysts and odontogenic tumors. Dental pulp tests and other techniques can serve as a reference for clinicians. The diagnosis is confirmed via histopathology. Surgical removal is a common treatment, with a good prognosis and a low recurrence rate.@*Conclusion@#The principle of treatment for an epidermoid cyst of the jaw is similar to that for a jaw cyst. The prognosis is good when the cyst is removed completely.

Retinal microstructure and developmental characteristics in Zebrafish / 解剖学报

Objective To study the microscopic structure and morphological characteristics of Zebrafish eyeball and retina at different developmental stages, and to lay a foundation for visual research model. Methods Select eight groups of zebrafish at different ages, with six fish in each group, 48 fish in total. Optical microscopy and transmission electron microscopy were used to observe the eyeball structure of Zebrafish at different developmental stages, and the thickness of retinal each layer was measured to analyze the temporal and spatial development pattern. The morphological characteristics of various cells in the retina and the way of nerve connection were observed from the microscopic and ultrastructural aspects, especially the structural differences between rod cells and cone cells. Results The retina of Zebrafish can be divided into ten layers including retinal pigment epithelial layer, rod cells and cone cells layer, outer limiting membrane, outer nuclear layer, outer plexiform layer, inner nuclear layer, inner plexiform layer, ganglion cell layer, nerve fiber layer, inner limiting membrane. Rod cells had a smaller nucleus and a higher electron density than cone cells. Photoreceptor terminals were neatly arranged in the outer plexiform layer, forming neural connections with horizontal cells and bipolar cells, and several synaptic ribbons are clearly visible within them. In Zebrafish retina, ganglion cell layer and inner plexiform layer are the earliest developed. With the growth and development of Zebrafish, the thickness of rod cells and cone cells layer and retinal pigment epithelial layer gradually increases, and the retinal structure was basically developed in about 10 weeks. Conclusion The retinal structure of Zebrafish is typical, with obvious stratification and highly differentiated nerve cells. There are abundant neural connections in the outer plexiform layer. The ocular development characteristics of Zebrafish are similar to those of most mammals.

Clinical analysis of orthodontic traction of impacted upper incisors / 口腔疾病防治

Objective@#To study the effect of orthodontic traction on the roots and periodontal soft and hard tissues of buried obstructed upper incisors.@*Methods@#This study was reviewed and approved by the ethics committee, and informed consent was obtained from the patients. From January 2018 to December 2022, 40 patients who underwent orthodontic traction on impacted upper incisors were selected; those whose contralateral homonymous apical foramen was not developed were placed in group A (23 cases), and those whose contralateral homonymous apical foramen was developed were placed in group B (17 cases). Software was used to measure the root length of the impacted upper incisors in groups A and B on cone beam CT (CBCT) images before and after traction and compare the changes in alveolar bone (alveolar bone width, labral bone plate thickness, and horizontal height of alveolar bone) and keratinized gingival width between each impacted upper incisor and the corresponding contralateral tooth immediately and one year after traction@*Results@#The root length of the impacted upper incisors increased after traction compared to before traction (P<0.05). The width of the alveolar bone at the completion of traction in group A was similar to that of the contralateral homonymous tooth (P>0.05), whereas the width of the alveolar bone at the completion of traction in group B did not reach that of the contralateral homonymous tooth, with a significant difference in width (P<0.05). Neither the labial bone plate height or width in group A or B reached that of the contralateral homonymous tooth after traction (P<0.05). The keratinized gingival width on the affected side was also significantly smaller than that on the contralateral side (P<0.05), but it was increased significantly in group A at the one-year follow-up visit (P<0.05).@*Conclusion@#Tooth traction is conducive to impacted upper incisor root growth, alveolar bone reconstruction and keratinized gingival growth but cannot produce complete symmetry with respect to the contralateral side.

Observation on the distribution of macular cone in healthy adult using adaptive optics scanning laser ophthalmoscope system / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To observe the distribution of cone in the macular of healthy adult in different ages using adaptive optics scanning laser ophthalmoscope(AO-SLO)system, and analyze its relationship with age.METHODS: A total of 100 healthy examinees(200 eyes)in our hospital from June to July 2023 were selected, and they were divided into four groups according to their age, with 25 cases(50 eyes)in each group, including 18-30 years in group A, 31-40 years in group B, 41-50 years in group C, 51-65 years in group D. AO-SLO was performed in both eyes and cone density was measured.RESULTS: The density of cone in the foveal eccentricity of 3° and 2.4°×2.4° in each group was different(P&#x003C;0.001), and the cone density in each area showed a relatively regular distribution characteristics, with the highest density in the temporal side, and the temporal&#x003E;nasal&#x003E;inferior&#x003E;superior sides from high to low. The mean cone density in the macular area of both eyes was 14 144.38±1 082.40, 13 241.24±535.32, 12 930.29±727.73, and 10 907.50±490.86 cell/mm2, respectively(P&#x003C;0.001), indicating that the cone density decreased with age. The correlation analysis showed that the mean cone density in the macular area was negatively correlated with age(r=-0.578, P&#x003C;0.001).CONCLUSION: AO-SLO is a quantitative non-invasive detection of cones, and there is a negative correlation between cone density and age in healthy human. Furthermore, density of cone in healthy people over 50 years was significantly decreased.

Prevalencia de conductos en C de segundos molares mandibulares evaluados en tomografía de haz cónico / Prevalence of C-ducts of Mandibular Second Molars Evaluated on Cone Beam Tomography

Introducción: El conocimiento adecuado de la configuración de conductos radiculares es fundamental en endodoncia; la evaluación tomográfica permite una correcta evaluación de su disposición radicular. Objetivo: Determinar la prevalencia de conductos en C de segundos molares mandibulares, evaluados en tomografía de haz cónico. Métodos: Se realizó un estudio descriptivo y de corte transversal; la muestra estuvo conformada por 200 segundos molares mandibulares permanentes de una población peruana, observadas en tomografías cone beam, donde se registró la presencia del conducto en C, su configuración según la clasificación de Fan y el sexo del paciente. Resultados: La prevalencia de la configuración radicular en forma de C en segundos molares inferiores fue del 65,5 por ciento; según la Clasificación de Fan se observó mayor prevalencia en el tercio cervical del conducto radicular el tipo C1 con 85,7 por ciento; en el tercio medio el tipo C2 con 42,9 por ciento; a nivel apical fue el tipo C3C con 72,1 por ciento; según el sexo, el 65,2 por ciento de los conductos en C correspondió al femenino. Conclusión: La prevalencia de los conductos en C de los segundos molares mandibulares evaluados en tomografías de haz cónico fue de 65,5 por ciento con mayor predominio en el sexo femenino. La evaluación tomográfica permite una mejor identificación y configuración interna de los conductos radiculares(AU)

Introduction: Adequate knowledge of the configuration of root canals is fundamental in endodontics; tomographic evaluation allows a correct assessment of their radicular arrangement. Objective: To determine the prevalence of C-shaped canals in mandibular second molars, evaluated by cone beam tomography. Methods: A descriptive and cross-sectional study was carried out; the sample consisted of 200 permanent mandibular second molars from a Peruvian population, observed in cone beam tomography, where the presence of the C-shaped canal, its configuration according to Fan's classification and the patient's gender were recorded. Results: The prevalence of the C-shaped root canal configuration in lower second molars was 65.5 percent; according to the Fan classification, the highest prevalence was observed in the cervical third of the root canal, type C1 with 85.7 percent; in the middle third, type C2 with 42.9 percent; at the apical level it was type C3C with 72.1 percent; according to gender, 65.2 percent of the C-shaped canals corresponded to females. Conclusion: The prevalence of C-shaped canals in mandibular second molars evaluated in cone beam tomography was 65.5% with a higher predominance in the female gender. The tomographic evaluation allows a better identification and internal configuration of the root canals(AU)

The impact of synthetic bone grafting for tissue regeneration: an in vivo study

Aims: This study aimed to examine the biological response of synthetic nanocomposite material on canine mandibular bone. Methods: Nine healthy adult male local breed dogs aged 12 to 18 months and weighing 10.2 to 15.2 kg were used in the study. Based on healing intervals of 1 and 2 months, the dogs were divided into 2 groups. Each group had 3 subgroups with 3 dogs each. The division was based on the grafting material used to fill the created defect: an empty defect (Control-ve), Beta-Tricalcium Phosphate, and nanocomposite (Beta-Tricalcium Phosphate and nanosilver 1%) . Surgery started after the dogs were anaesthetized. The surgical procedure began with a 5 cm parallel incision along the mandible's lower posterior border. After exposing the periosteum, a three 5mm-diameter, 5-mmdeep critical-size holes were made, 5mm between each one. Each group's grafting material had independent 3 holes. The defects were covered with resorbable collagen membranes followed by suturing of the mucoperiosteal flap. Results: Total densitometric analysis showed no significant differences between groups at 1-month intervals, with the nanocomposite group having a higher mean rank (165.66± 31.21) in comparison to other groups while at 2 months intervals that there was a highly significant difference between three groups as the P-value was (0.000) with the nanocomposite group having a higher mean rank (460.66± 26.40). Conclusions: In the current study, the use of nanocomposites improved osteoconductivity by accelerating new bone formation. Moreover, the encorporation of nanosilver enhanced growth factor activity. These attributes make nanocomposites a promising material for enhancing the bone healing process

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.

Frecuencia de Signos Óseos de Osteoartritis en la Articulación Temporomandibular en una Población Adulta Chilena Mediante CBCT, Durante 2021-2022

La osteoartritis (OA) de la articulación temporomandibular (ATM) es un desorden degenerativo de etiología multifactorial, que requiere un manejo interdisciplinario. Es considerada como la enfermedad degenerativa más frecuente de la articulación. Por esto es importante conocer lo más preciso posible las estructuras internas del área donde se requiere realizar la intervención o tratamiento, en este caso la ATM. Para esto existen distintos exámenes radiográficos complementarios como: tomografía computarizada, resonancia magnética y por último la tomografía computarizada de haz cónico (CBCT), debido a su capacidad de visualizar tridimensionalmente y con buena definición las estructuras óseas y distintas patologías o alteraciones presentes. A pesar de esto, no hay suficiente evidencia actual que demuestre la frecuencia de signos óseos de osteoartritis presentes en ATM según edad y sexo en la población Chilena. El objetivo este trabajo consistió en Determinar frecuencia de los signos óseos en osteoartritis de ATM mediante CBCT en una población adulta Chilena atendida en un centro radiológico durante los años 2021-2022. Se realizó un estudio observacional descriptivo, donde se observó informes radiológicos de CBCT en pacientes adultos atendidos en el centro radiológico privado de Valdivia durante el periodo del primer semestre del 2021 a primer semestre 2022. Se evaluó la presencia de los siguientes signos óseos imagenológicos: aplanamiento de superficie articular, erosión superficial, osteofitos condilares, esclerosis subcondral, quistes subcortical, esclerosis generalizada, cuerpos libres intraarticulares, reabsorción completa y parcial de la cabeza condilar y trabeculado heterogéneo. De un total de 101 exámenes, 70 exámenes fueron considerados válidos para este estudio según los criterios de selección. Los 31 exámenes restantes no calificaron según los criterios o no presentaban osteoartritis de ATM. De los 70 pacientes 58 pertenecían a mujeres y 12 a hombres. El promedio de edad fue de 37,2 años. Los signos imagenológicos más frecuentes fueron: Trabeculado heterogéneo, Aplanamiento de la superficie articular, Esclerosis subcondral condilar.

Osteoarthritis (OA) of the temporomandibular joint (TMJ) is a degenerative disorder of multifactorial etiology, requiring interdisciplinary management. It is considered the most common degenerative joint disease. For this reason, it is important to know asprecisely as possible the internal structures of the area where the intervention or treatment is required, in this case the TMJ. For this purpose, there are several additional radiographic examinations such as: computed tomography, magnetic resonance imaging and finally cone-beam computed tomography (CBCT), due to its ability to visualize three-dimensionally and with good definition the bone structures and different pathologies or present alterations. Despite this, there is not enough current evidence to demonstrate the frequency of osteoarthritis bone signs present in TMJ according to age and gender in the Chilean population. The aim of this study was to determine the frequency of bone signs of TMJ osteoarthritis through CBCT in a Chilean adult population attended in a radiological center during 2021-2022. A descriptive observational study was made, where CBCT radiological reports were observed in adult patients attended in a private radiological center in Valdivia during the first semester of 2021 to the first semester of 2022. The presence of the following imaging bone signs was evaluated: flattening of the articular surface, surface erosion, condylar osteophytes, subchondral sclerosis, subcortical cysts, generalized sclerosis, intraarticular free bodies, complete and partial reabsorption of the condylar head and heterogeneous trabeculate. Of a total of 101 examinations, 70 examinations were considered valid for this study according to the selection criteria. The remaining 31 examinations did not qualify according to the criteria or did not present TMJ osteoarthritis. Of the 70 patients, 58 were female and 12 were male. The average age was 37.2 years. The most frequent imaging signs were: heterogeneous trabeculation, flattening of the articular surface, subchondral condylar sclerosis.

O uso do planejamento virtual na cirurgia ortognática / The use of virtual planning in orthognathic surgery

Introdução: A cirurgia ortognática envolve manipulação da arquitetura óssea facial, através de osteotomias, para restaurar a forma e a função, corrigindo a má oclusão, as desproporções maxilomandibulares e assimetrias faciais. O planejamento virtual em cirurgia ortognática é realizado com ajuda de softwares que utilizam as medidas reais do esqueleto craniofacial e registros da oclusão do paciente, através de uma análise 3D. Método: Foram avaliados 18 pacientes com deformidades dentofaciais, de acordo com a classificação de Angle submetidos a cirurgia ortognática com o uso do planejamento virtual, entre 2018 e 2019. Os critérios de inclusão foram pacientes entre 16 e 60 anos com desproporções maxilo-mandibulares nas quais o tratamento ortodôntico isolado não era suficiente. Os critérios de exclusão foram a presença de lesões císticas ou tumorais nos maxilares e comorbidades clínicas que contraindicavam a cirurgia. O planejamento virtual foi realizado em todos os pacientes, utilizando o software Dolphin® Imaging 11 e os guias cirúrgicos confeccionados em impressora 3D. Resultados: O guia cirúrgico intermediário apresentou adaptação perfeita nas faces oclusais promovendo grande estabilidade para o reposicionamento e fixação da maxila na oclusão intermediária. Os 18 pacientes operados responderam como "totalmente satisfeitos" em relação ao resultado estético-funcional nessa série estudada. Foi encontrada uma semelhança muito grande da posição do esqueleto maxilofacial no planejamento virtual préoperatório e o obtido no pós-operatório, através da avaliação das telerradiografias. Conclusão: O planejamento virtual em cirurgia craniomaxilofacial possui inúmeras vantagens, como diminuição do tempo laboratorial pré-operatório, maior precisão na confecção dos guias cirúrgicos e melhor reprodutibilidade dos resultados simulados.

Introduction: Orthognathic surgery involves the manipulation of facial bone architecture through osteotomies to restore form and function, correcting malocclusion, maxillomandibular disproportions, and facial asymmetries. Virtual planning in orthognathic surgery is carried out with the help of software that uses real measurements of the craniofacial skeleton and records of the patient's occlusion through 3D analysis. Method: 18 patients with dentofacial deformities were evaluated, according to Angle's classification, who underwent orthognathic surgery using virtual planning between 2018 and 2019. The inclusion criteria were patients between 16 and 60 years old with maxylo-mandibular disproportions in which orthodontic treatment alone was not sufficient. Exclusion criteria were the presence of cystic or tumoral lesions in the jaw and clinical comorbidities that contraindicated surgery. Virtual planning was carried out on all patients, using Dolphin® Imaging 11 software and surgical guides made with a 3D printer. Results: The intermediate surgical guide presented perfect adaptation on the occlusal surfaces, promoting great stability for the repositioning and fixation of the maxilla in intermediate occlusion. The 18 operated patients responded as "completely satisfied" in relation to the aesthetic-functional result in this series studied. A very great similarity was found between the position of the maxillofacial skeleton in the preoperative virtual planning and that obtained post-operatively through the evaluation of teleradiography. Conclusion: Virtual planning in craniomaxillofacial surgery has numerous advantages, such as reduced pre-operative laboratory time, greater precision in the creation of surgical guides, and better reproducibility of simulated results.

Cone-Beam Computed Tomography to evaluate changes in trabecular lower jawbone microstructure caused by bone loss and antiresorptive treatment / CBCT para evaluar cambios en la microarquitectura ósea de la mandíbula por pérdida ósea y tratamiento antirresortivo

ABSTRACT For decades, conventional histomorphometry has been the gold standard for analyzing trabecular bone microarchitecture. In recent years, micro-computed tomography (μCT) devices have been validated and are now considered the gold standard for quantifying bone microstructure Aim The aim of this preliminary report is to evaluate the usefulness of CBCT to assess trabecular mandible microstructural properties in normal ewes and to compare the quantitative changes associated with ovariectomy and antiresorptive treatment Material and Method Twelve adult Corriedale ewes (n=4/group) aged 3-4 years were divided into 3 groups and studied for 28 months. Eight ewes were ovariectomized (OVX) and divided into OVX and OVX+ZOL groups (n=4/group) which were treated as follows, by jugular injection: OVX received saline solution and OVX+ZOL received zoledronate (Zol) (Gador SA, CABA, Argentina) (4 mg/month). Another four ewes were subjected to sham surgery (SHAM group) and received saline solution Results Densitometry showed that jaw mineral content (BMC) and density (BMD) were significantly lower in OVX than in SHAM and OVX+ZOL ewes; no difference was observed between OVX+ ZOL and SHAM groups. CBCT analysis showed that bone volume (BV/TV%); trabecular thickness (TbTh); connectivity density (CD) and anisotropy degree (AD) were significantly lower, and trabecular spacing (TbSp), significantly higher in OVX than in SHAM ewes. AD was significantly higher and TbSp significantly lower in OVX+ZOL than in OVX groups. BV/TV%, TbTh and CD showed a clear tendency to being higher in OVX+ZOL than in OVX groups. No statistical difference was observed between OVX+ZOL and SHAM ewes. CBCT in a nondestructive, fast, very precise procedure for measuring bone morphometric indices without biopsies, which are not indicated for morphometric evaluation in osteoporosis Conclusions The current study demonstrated the potential of the high-resolution CBCT imaging to assess in vivo quantitative bone morphometry and bone quality of lower jaw cancellous bone under normal conditions and to differentiate changes associated with excessive bone loss induced by estrogen withdrawal and antiresorptive intervention.

RESUMEN Objetivo El presente informe preliminar evaluó la utilidad de Tomografía Computada de Haz Cónico (CBCT) para analizar las propiedades microestructurales trabeculares del maxilar inferior de ovejas y comparar los cambios cuantitativos asociados con la ovariectomía y tratamiento antirresortivo. Se estudiaron dieciséis ovejas Corriedale adultas de 3-4 años Materiales y Método Doce ovejas fueron ovariectomizadas (OVX) y divididas en 2 grupos: OVX y OVX+ZOL (n=4/grupo) cuyo tratamiento por inyección endovenosa en la yugular durante 28 meses fue el siguiente: OVX con solución salina y OVX+ZOL con zoledronato (Gador S.A. CABA. Argentina) (Zol) (4 mg/mes); 4 ovejas fueron sometidas a cirugía simulada (grupo SHAM) Resultados La densitometría (Lunar DPX) mostró que el contenido mineral del hueso maxilar (CMO) y la densidad (DMO) fueron significativamente más bajos en OVX que en SHAM y OVX+ZOL; no se observaron diferencias entre los grupos OVX+ZOL y SHAM. El análisis de las imágenes por CBCT (Planmeca Promax 3D Classic) mostró que el volumen óseo (BV/TV%); el espesor trabecular (TbTh); la densidad de conectividad (CD) y el grado de anisotropía (AD) fueron significativamente menores (p<0.05), y el espaciado trabecular (TbSp), significativamente mayor en OVX que en SHAM (p<0.05). AD fue significativamente mayor (p<0.05) y TbSp, significativamente menor en OVX+ZOL que en OVX (p<0.05). BV/TV%, TbTh y CD mostró una clara tendencia a ser mayor en OVX+ZOL que en OVX. No se observaron diferencias estadísticas entre OVX+ZOL y SHAM Conclusiones En base a nuestros resultados consideramos que CBCT presenta suficiente confiabilidad y validez para evaluar in vivo la morfometría cuantitativa y la calidad del hueso esponjoso del maxilar inferior en condiciones normales, así como para diferenciar los cambios en dichos parámetros asociados a la pérdida ósea excesiva por la caída estrogénica e intervención antirresortiva. Aunque se necesitan estudios futuros, nuestros resultados agregarían una herramienta no invasiva adicional para diferenciar la microestructura del hueso trabecular mandibular en estudios preclínicos , sentando las bases para su futura aplicación en la práctica clínica.

Contribution of Digital Technology to the Surgical Technique of Miniscrew Insertion: a Literature Review

Orthodontic miniscrews are used to achieve absolute anchorage. Their insertion technique is simple but must be precise to avoid intra- and postoperative complications. This study aimed to review the literature on the role of digital technology in the precise placement of miniscrews and to describe the different stages of the insertion guide manufacturing chain. The databases used were PubMed, Science Direct, and Google Scholar, including the following English descriptors: "Orthodontic Anchorage Procedures," "Cone Beam Computed Tomography." Digital technology improves the accuracy of miniscrew placement by using 3D imaging to assess the quantity and quality of bone and the proximity of anatomical structures in the area to be implanted. By combining 3D imaging with the new techniques of 3D printing and virtual planning, the orthodontist can obtain a personalized placement guide for the patient using computer-aided design and manufacturing techniques. A digitally-assisted miniscrew insertion system is a promising technique for precise and safe miniscrew insertion but cannot be used routinely. Therefore, large-scale studies are needed to map miniscrew insertion in different areas, considering ethnicity, gender, and different anatomical characteristics.

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.

Cirugía virtual guiada para rehabilitación implantosoportada de maxilar edéntulo con carga inmediata / Virtual guided surgery for implantsupported rehabilitation of the edentulous maxilla with immediate loading

Objetivo: Presentar el relato de un caso clínico de cirugía virtual guiada para rehabilitación implantosoportada de maxilar edéntulo con carga inmediata. Relato del caso: Paciente, edéntulo total en ambos maxilares, expresó su deseo de cambiar la prótesis total superior removible por una prótesis total fija sobre implantes. Durante la evaluación clínica, se observaron condiciones biológicas favorables al tratamiento como, adecuada faja de tejido queratinizado y leve reabsorción ósea. Como tratamiento se le sugiere al paciente, una planificación inversa, asistida por cirugía virtual guiada, utilizando un prototipo de guía quirúrgica para la colocación de seis implantes dentales en el maxilar y la instalación de una prótesis protocolo de carga inmediata. Conclusiones: Los resultados nos permiten concluir que la cirugía virtual guiada por computadora para rehabilitación protésica implantosoportada de maxilar edéntulo, con carga inmediata, proporciona precisión en los procedimientos quirúrgicos, es fundamental para la confección de prótesis inmediatas, representa una alternativa mínimamente invasiva y el resultado complace a los pacientes.

Objective: present the report of a clinical case of a virtual guided surgery for implant-supported rehabilitation of the edentulous maxilla with immediate loading. Case report: Patient, bi-maxillary edentulous expressed the desire to replace the removable upper total prothesis for a total fixed prothesis on implants. During the clinical evaluation, favorable biological conditions for treatment were observed, such as adequate keratinized tissue band and mild bone resorption. As part of the treatment, the patient was recommended a reverse planning approach, assisted by virtual guided surgery. This involved a prototype surgical guide for the fixation of six dental implants in the maxilla and the installation of an immediate loading protocol prosthesis. Conclusions: The results lead us to conclude that computer-guided virtual surgery for implant-supported prosthetic rehabilitation of the edentulous maxilla with immediate loading, provides a high precision in surgical procedures. It is essential to fabrication of immediate prostheses, represents a minimally invasive alternative, and results in patient satisfaction.

Jóvenes y educación superior en el Cono Sur de América

(analítico) Con la finalidad de conocer la experiencia de ser joven hoy en la educación superior en Argentina, Chile o Uruguay, se realiza un análisis temático a 54 artículos de los últimos tres años en WoS, Scopus y Scielo. Por intermedio de un trabajo inductivo y reflexivo, se identifican patrones comunes en las fuentes de análisis, que permiten identificar siete temas que dan cuenta de una transición: ampliación de cobertura, pero sin inclusión; facilidad al ingreso, pero con incertidumbre al egreso; cambios en los roles de género, pero manteniéndose el machismo; valoración de la salud, pero con conductas de riesgo; preocupación por los otros, pero con individualismo; valoración del movimiento estudiantil, pero con cambios en sus manifestaciones y tránsito de lo presencial a lo virtual, acelerado por covid-19.

(analytical) In order to know the experience of being young today in higher education in Argentina, Chile or Uruguay, a Thematic Analysis is carried out on 54 articles from the last three years in WoS, Scopus and Scielo. Through inductive and reflective work, common patterns are identified in the sources of analysis, which allow the identification of seven themes that account for a transition: expansion of coverage, but without inclusion; ease upon admission, but with uncertainty upon discharge; changes in gender roles, but maintaining machismo; health assessment, but with risk behaviors; concern for others, but with individualism; appreciation of the student movement, but with changes in its manifestations and transition from face-to-face to virtual, accelerated by COVID-19.

(analítico) Para conhecer a experiência de ser jovem hoje na educação superior na Argentina, Chile ou Uruguai, realiza-se uma Análise Temática de 54 artigos dos últimos três anos em WoS, Scopus e Scielo. Através de um trabalho indutivo e reflexivo, identificam-se padrões comuns nas fontes de análise, que permitem identificar sete temas que dão conta de uma transição: ampliação da cobertura, mas sem inclusão; facilidade na admissão, mas com incerteza na alta; mudanças nos papéis de gênero, mas mantendo o machismo; avaliação de saúde, mas com comportamentos de risco; preocupação com os outros, mas com individualismo; valorização do movimento estudantil, mas com mudanças em suas manifestações e transição do presencial para o virtual, acelerada pela Covid-19.

Corrección del artefacto producido en imágenes tomográficas en equipos odontológicos / Correction of the artifact produced in tomographic images in dental equipment

Objetivo: disminuir el efecto de artefacto que generan objetos de alta densidad mediante la utilización de filtros de distintos materiales y espesores, ubicados en lugares estratégicos del tomógrafo. Material y métodos: se utilizaron filtros de aluminio y de cobre ubicados en lugares estratégicos en el equipo tomográfico. Se realizaron cortes oblicuos en piezas dentarias con restauraciones metálicas y en implantes; se midió la extensión del artefacto en ancho y alto en cada adquisición tomográfica. Resultados: se hallaron diferencias significativas respecto a la disminución de la dispersión de acuerdo con cada filtro con respecto a la no utilización de estos elementos. Conclusión: la utilización de filtros logró disminuir el efecto de artefacto en estructuras de alta densidad, obteniendo una mejor calidad de imagen para el diagnóstico, permitiendo que el software pueda reconstruir una imagen real (AU)

Objective: to diminish the artifact effect generated by high density objects by using filters of different materials and thickness, located in strategic places of the tomograph. Material and methods: aluminum and copper filters located in strategic places in the tomographic equipment were used. Oblique cuts were made on dental pieces with metal restorations and implants; the extension of the artifact in width and height was measured in each tomographic acquisition. Results: significant differences were found regarding the decrease of the dispersion according to each filter with respect to the non-use of these elements. Conclusion: the use of filters achieves to diminish the artifact effect in structures of high density, obtaining a better image quality for the diagnosis, allowing the software to reconstruct a real image (AU)

Influencia de la Morfología Externa de la Raíz de Primeros Premolares Superiores en la Sobreestimación del Espesor Radiográfico Radicular Durante la Preparación para Poste, Evaluados Mediante Tomografía Computarizada Cone Beam / Influence of the External Morphology of the Root of Upper First Premolars on the Overestimation of Radiographic Root Thickness During Post Preparation, Evaluated by Cone Beam Computed Tomography

La investigación tuvo como objetivo determinar la influencia de la morfología externa de la raíz de primeros premolares superiores en la existencia de sobreestimación radiográfica durante la preparación para poste. Con este fin se realizó un estudio transversal in vitro, donde 60 premolares superiores uniradiculares fueron instrumentadas con fresas Gates Glidden y Pesso de calibre 1, 2 y 3. Seguidamente se obtuvieron imágenes radiográficas digitales de cada pieza dentaria mediante un aparato posicionador a una distancia constante en sentido vestíbulo lingual, asimismo se realizaron imágenes tomográficas volumétricas de las muestras. En ambas técnicas imagenológicas se midió el espesor a mesial y distal de las piezas. La sobreestimación fue calculada mediante la diferencia de la medida tomográfica menos la radiográfica. Los resultados indicaron que en ambas paredes radiculares hubo diferencia significativa entre las medidas radiográficas y tomográficas (p<0,05), encontrándose en la pared distal diferencias altamente significativas (p<0,001); además se evidenció que la sobreestimación radiográfica fue mayor en la pared distal. El estudio concluyó que existe sobreestimación radiográfica en premolares superiores durante la preparación para poste de un 20,42 % en promedio, siendo la pared distal la estructura que presenta mayor sobreestimación.

SUMMARY: he investigation´s objective was to determine the influence of external morphology of the root of upper first premolars in the existence of radiographic overestimation during preparation for post. An in vitro cross-sectional study was carried out, where 60 single-rooted upper premolars were instrumented with burs. Gates Glidden and Pesso of caliber 1, 2 and 3, then, digital radiographic images of each dental piece were obtained by means of a positioning device at a constant distance in the buccolingual direction; volumetric tomographic images of the samples were also performed. In both imaging techniques, the mesial and distal thickness of the pieces was measured. The overestimation was calculated by the difference of the tomographic measurement minus the radiographic one. The results indicated that in both root walls there was a significant difference between the radiographic and tomographic measurements (p<0.05), with highly significant differences being found in the distal wall (p<0.001); In addition, it was evidenced that the radiographic overestimation was greater in the distal wall. The study concluded that there is radiographic overestimation in upper premolars during post preparation of 20.42% on average, with the distal wall being the structure that presents the greatest overestimation.