Reabsorción radicular en premolares, posterior a ortodoncia de autoligado, utilizando tomografía computarizada

Este Estudio tuvo por objetivo determinar la incidencia de reabsorción radicular externa en premolares superiores e inferiores permanentes al finalizar el tratamiento de ortodoncia. Esta investigación fue realizada en pacientes entre 18 y 35 años que recibieron tratamiento de ortodoncia, sin extracciones, con técnica de autoligado en la ciudad de Guadalajara. Se consideraron 120 premolares, realizando mediciones longitudinales en las tomografías computarizadas de haz cónico al inicio y término del tratamiento. Utilizando el software Implant Viewer 3. Los valores registrados en el primer y segundo premolar superior tanto del lado derecho como izquierdo al inicio y término del tratamiento fluctuaron entre -4.946 y -7.801; p ≤ 0.0005 encontrándose diferencias estadísticas significativas. Mientras que en el primer y segundo premolar inferior tanto del lado derecho como izquierdo, fluctuaron entre -4.864 y -5.28; p ≤ 0.0005 encontrándose diferencias estadísticas significativas. Se concluye en este estudio que los dientes sometidos a movimientos durante el tratamiento de ortodoncia sufren modificaciones en el contorno de la raíz, cambios con consecuencias mínimas que no comprometen la funcionalidad del diente. Los premolares superiores presentaron mayores rangos de reabsorción radicular que los premolares inferiores.

The aim of this study is to determine the incidence of root resorption in permanent upper and lower premolars at the end of an orthodontic treatment. This research was carried out in patients aged between 18 and 35 years old who received orthodontic treatment, without extractions, with a self-ligating technique in the city of Guadalajara, Mexico. In this study, 120 premolars were considered, making longitudinal measurements with cone beam computed tomography at the beginning and the end of the treatment, using the Implant Viewer 3 software. The values recorded in the upper first and second premolars on both the right and left sides at the beginning and the end of the treatment fluctuated between -4.946 and -7.801; p ≤ 0.0005, finding statistically significant differences. In the lower first and second premolars on both the right and left sides, they fluctuated between -4.864 and -5.28; p ≤ 0.0005, also finding statistically significant differences. It is concluded that teeth subjected to movements during orthodontic treatment suffer modifications in the contour of the root, changes with minimal consequences that do not compromise their functionality. The upper premolars showed higher ranges of root resorption than the lower premolars.

Mandibular Incisive Canal Morphometry: A Cone-Beam Computed Tomography Study in Jordan

SUMMARY: Mandibular incisive canal (MIC) and related mental foramen (MF) and anterior loop (AL) morphometrics are important landmarks in medical and dental clinical applications. The main aim of this retrospective study to determine the morphometry of the mandibular incisive canal (MIC) in a Jordanian population and to propose a new shape-pattern classification of the MIC. In addition, MF and AL morphometrics were determined. Carestream 3D imaging software was used on 100 Cone-Beam Computed Tomography (CBCT) of a Jordanian population to determine the MF, AL and MIC morphometrics. The detection prevalence of the MIC was 96 %. The right and left MIC showed four distinct line patterns, proposed for the first time in this paper. The line-patterns were angular (L-line), straight (I-line), curved (V-line) and wavy (W-line), with a prevalence of 41 %, 19 %, 25.5 %, and 10.5 %, respectively. MF was detected in all mandibles with a round shape in 58 % of the images. The most common horizontal and vertical positions of the MF were H4 and H3 (73.5 %) and V3 and V2 (95 %), respectively. An accessory MF was detected in 14.5 % of the samples and was more prevalent in males and on the right side. AL was detected in 92.5 % of the samples and exhibited a pattern prevalence of 25.5 %, 40 % and 27 % for types I, II and III, respectively. Results revealed that asymmetry and gender differences between right and left MIC, MF, AL and AMF was seen in patient's mandibles. In conclusion, this is the first study to propose and show that Mandibular incisive canal exhibits four potential line patterns (L, I, V and W lines patterns). Gender and ethnic variations of the mandibular canal landmarks morphometrics of both right and left hemi-mandible are important to be acknowledged in learning anatomy and when planning or performing dental and medical procedures.

Las relaciones de la morfometría del canal incisivo mandibular (MCI), del foramen mentoniano (FM) y del asa anterior (AA) son hitos importantes en las aplicaciones clínicas médicas y dentales. El objetivo principal de este estudio retrospectivo fue determinar la morfometría del MCI en una población jordana y proponer una nueva clasificación de patrón de forma del MCI. Además, se determinaron la morfometría de FM y AA. Se utilizó el software de imágenes 3D Carestream en 100 tomografías computarizadas de haz cónico (CBCT) de una población jordana para determinar la morfometría de FM, MCI y AA. La prevalencia de detección de MCI fue del 96 %. El MCI derecho e izquierdo mostraron cuatro patrones de líneas distintas, propuestas por primera vez en este artículo. Los patrones de líneas fueron angulares (línea L), rectos (línea I), curvos (línea V) y ondulados (línea W), con una prevalencia del 41 %, 19 %, 25,5 % y 10,5 % respectivamente. Se detectó el FM en todas las mandíbulas y con forma redonda en el 58 % de las imágenes. Las posiciones horizontal y vertical más comunes del FM fueron H4 y H3 (73,5 %) y V3 y V2 (95 %), respectivamente. Se detectó FM accesorio en el 14,5 % de las muestras y fue más prevalente en el sexo masculino y en el lado derecho. AA se detectó en el 92,5 % de las muestras y exhibió un patrón de prevalencia del 25,5 %, 40 % y 27 % para los tipos I, II y III, respectivamente. Los resultados revelaron asimetría y diferencias en el sexo entre MCI, FM, AA derecha e izquierda en las mandíbulas de los pacientes. En conclusión, este es el primer estudio que propone y muestra que el canal incisivo mandibular exhibe cuatro patrones de líneas potenciales (patrones de líneas L, I, V y W). Es importante reconocer las variaciones étnicas y de sexo de la morfometría de los puntos de referencia del canal mandibular de la hemimandíbula derecha e izquierda al estudiar y aprender anatomía y al planificar o realizar procedimientos médicos y dentales.

Beneficios de la descompresión y enucleación en lesiones quísticas de gran tamaño en la mandíbula / Benefits of decompression and enuclation in large cystic lesions in the jaw / Benefícios da descompressão e enuclação nas grandes lesões císticas na mandíbula

Las lesiones quísticas ocurren en los maxilares, por la presencia de células remanentes del neuroectodermo embrionario. La descompresión es una técnica conservadora para disminuir la presión intraquística mediante drenaje constante, permitiendo el crecimiento de nuevo hueso centrípeto de las paredes óseas del quiste. Objetivo: determinar los beneficios de la descompresión y enucleación en lesiones quísticas mandibulares, tomando como base la metodología de un caso clínico. Descripción del caso: se diagnosticó una lesión quística mandibular en paciente masculino de 27 años, que acudió a consulta mostrando secreción purulenta en mucosa trígono retromolar de UD 37, inicialmente asintomática. Se utilizaron como materiales la tomográfica computarizada de haz cónico, artefacto de drenaje autocurado, hemiarcada izquierda elaborada con Metil Metacrilato y aparato a base de cilindro. Como resultados se reveló imagen hipodensa de bordes definidos localizada en el límite posterior de cuerpo mandibular, borde anterior y parte de la rama ascendente mandibular del lado izquierdo; extendida en sentido cefálico caudal desde la cresta alveolar y borde anterior de la rama hasta la cortical superior del conducto mandibular. Conclusión: Se confirmó diagnóstico de quiste periapical, quiste residual y ameloblastoma. Se realizó biopsia incisional de la lesión para estudio histopatológico y la descompresión con dispositivo personalizado a enucleación conminada con solución de Carnoy, resultando el tratamiento conservador efectivo complementado por la enucleación de una membrana quística más gruesa y menos friable.

Cystic lesions occur in the jaws due to the presence of remnant cells of the embryonic neuroectoderm. Decompression is a conservative technique to decrease intracystic pressure by constant drainage, allowing the growth of new centripetal bone from the bony walls of the cyst. Objective: to determine the benefits of decompression and enucleation in mandibular cystic lesions, based on the methodology of a clinical case. Case description: a cystic mandibular lesion was diagnosed in a 27 year old male patient, who came for consultation showing purulent secretion in the trigone retromolar mucosa of UD 37, initially asymptomatic. The materials used were cone beam computed tomography, self-curing drainage device, left hemiarch made with Methyl Methacrylate and cylinder based apparatus. The results revealed a hypodense image with defined borders located in the posterior limit of the mandibular body, anterior border and part of the ascending mandibular branch on the left side; extended in a caudal cephalic direction from the alveolar crest and anterior border of the branch to the superior cortical of the mandibular duct. Conclusion: Diagnosis of periapical cyst, residual cyst and ameloblastoma was confirmed. An incisional biopsy of the lesion was performed for histopathological study and decompression with a customized device to enucleation with Carnoy's solution, resulting in effective conservative treatment complemented by enucleation of a thicker and less friable cystic membrane.

As lesões císticas ocorrem nos maxilares, devido à presença de células remanescentes da neuroectoderme embrionária. A descompressão é uma técnica conservadora que visa reduzir a pressão intracística por meio de drenagem constante, permitindo o crescimento de novo osso centrípeto a partir das paredes ósseas do cisto. Objetivo: determinar os benefícios da descompressão e da enucleação em lesões císticas mandibulares, com base na metodologia de um caso clínico. Descrição do caso: foi diagnosticada uma lesão cística mandibular em um paciente do sexo masculino, 27 anos, que se apresentou para consulta apresentando secreção purulenta na mucosa do trígono retromolar do UD 37, inicialmente assintomática. Os materiais utilizados foram tomografia computadorizada de feixe cônico, dispositivo de drenagem autopolimerizável, hemiarco esquerdo confeccionado com metacrilato de metila e aparelho de base cilíndrica. Os resultados revelaram uma imagem hipodensa com limites definidos localizada no limite posterior do corpo mandibular, bordo anterior e parte do ramo mandibular ascendente do lado esquerdo; estendendo-se em direção cefálica caudal desde a crista alveolar e bordo anterior do ramo até ao córtex superior do ducto mandibular. Conclusão: Foi confirmado o diagnóstico de quisto periapical, quisto residual e ameloblastoma. Foi efectuada uma biopsia incisional da lesão para estudo histopatológico e descompressão com um dispositivo adaptado à enucleação cominutiva da solução de Carnoy, resultando num tratamento conservador eficaz complementado pela enucleação de uma membrana quística mais espessa e menos friável.

Descripción de la Morfología del Sistema de Canales Radiculares en Premolares Maxilares Mediante Tomografía Computarizada Cone Beam en una Población Chilena

El tratamiento endodóntico requiere detallados conocimientos sobre la morfología radicular. En premolares maxilares, se ha reportado variabilidad en el número de raíces y morfología del sistema de canales radiculares (SCR). La causa más frecuente de fracaso endodóntico son los conductos no tratados. Por lo tanto, una mejor compresión de la morfología del SCR y sus variaciones es crucial para el tratamiento endodóntico. El objetivo de esta investigación fue describir la frecuencia del número de raíces y morfología del SCR en premolares maxilares, mediante exámenes de tomografía computarizada Cone Beam (CBCT) en una población chilena. Se realizó un estudio observacional descriptivo de corte transversal donde se observó la morfología del sistema de canales radiculares de primeros y segundos premolares maxilares a través de exámenes CBCT, agrupándolos de acuerdo con la Clasificación de Vertucci. Se observaron 228 exámenes CBCT, donde se incluyeron 268 primeros premolares superiores y 233 segundos premolares maxilares. Se determinó que en primeros premolares maxilares un 56,3 % presentó una raíz, un 43,3 %, siendo más frecuente una morfología del SCR tipo IV. En los segundos premolares maxilares, se determinó la presencia de una raíz en el 95,7 % de los casos, siendo más frecuente una morfología del SCR tipo I. Estos resultados pueden ser de interés para endodoncistas, ya que conocer la morfología del SCR de premolares maxilares permite mejorar la planificación de la terapia endodóntica realizada en estos dientes.

Endodontic treatment requires detailed knowledge of root morphology. In maxillary premolars, variability in root number and root canal system (RCS) morphology has been reported. The most frequent cause of endodontic failure is non treated canals. Therefore, a better understanding of RCS morphology and its variations is crucial for endodontic treatment. The aim of this research was to describe the frequency of root number and SCR morphology in maxillary premolars, by means of Cone Beam Computed Tomography (CBCT) examinations in a Chilean population. A cross-sectional descriptive observational study was carried out in which the morphology of the root canal system of maxillary first and second premolars was observed through CBCT examinations, grouping them according to the Vertucci Classification. A total of 228 CBCT examinations were observed, which included 268 upper first premolars and 233 maxillary second premolars. It was determined that in maxillary first premolars 56.3 % presented one root, 43.3 %, being more frequent a SCR type IV morphology. In maxillary second premolars, the presence of one root was determined in 95.7 % of the cases, being more frequent a SCR type I morphology. These results may be of interest to endodontists, since knowing the morphology of the RCS of maxillary premolars allows improving the planning of endodontic therapy performed on these teeth.

Evaluación de Protocolos de Autotrasplante Dental Guiado y sus Tasas de Supervivencia y Éxito. Una Revisión Sistemática

Actualmente los factores que influyen en la supervivencia de los dientes trasplantados han podido ser controlados con el uso de la tecnología. El autotrasplante dental guiado ha logrado más predictibilidad y eficiencia, además, h a reducido los tiempos de transferencia desde la extracción hasta el trasplante. El objetivo de esta revisión es describir los protocolos de autotrasplante dental guiado, sus tasas de supervivencia y éxito publicados en la literatura actual. Esta revisió n fue realizada siguiendo la pauta PRISMA. La búsqueda se realizó en MEDLINE, Google Académico, ScienceDirect y SciELO, con los términos "autotransplant", "autotransplantation", "autotransplanting", "dental", "tooth", "teeth", "guided", "guide" con filtro de publicación de 10 años. Se realizó evaluación de riesgo de sesgo mediante pautas Joanna Briggs Institute (JBI) a los estudios, incluyendo en esta revisión sólo con riesgo medio y bajo. Los datos de cada artículo se tabularon en una tabla realizada en el procesador de texto en línea "Google Docs". Diez estudios cumplieron los criterios mencionados y fueron incluidos. Fueron evaluados un total de 37 pacientes entre 9 a 64 años. Los dientes donantes más frecuentes fueron premolares y terceros molares. En la mayoría de los casos los pacientes se encontraban sin antecedentes mórbidos de relevancia. El éxito fue evaluado mediante diversos criterios clínicos y radiográficos. Por otro lado, la supervivencia fue evaluada durante los seguimientos respecto a la permanencia del diente en boca. Este tipo de tratamiento no es muy conocido y los estudios incluidos fueron escasos, por otro lado, estos son de bajo nivel de evidencia (reportes de casos y serie de casos). Los protocolos evaluados difieren en algunas características, sin embargo, todos logran altas tasas de supervivencia y éxito. Igualmente, se presentan algunos fracasos, dónde los dientes debieron ser extraídos por movilidad e inflamación.

Currently, the factors that influence the survival of transplanted teeth have been controlled with the use of technology. Guided dental autotransplantation has achieved greater predictability and efficiency, and has also reduced transfer times from extraction to transplantation. The aim of this review is to describe the protocols of guided dental autotransplantation, their survival and success rates published in the current literature. This review was performed following the PRISMA guideline. The search was carried out in MEDLINE, Google Scholar, ScienceDirect and SciELO, with the terms "autotransplant", "autotransplantation", "autotransplanting", "autotransplanting", "dental", "tooth", "teeth", "guided", "guide" with a 10-year publication filter. Studies were assessed for risk of bias using Joanna Briggs Institute (JBI) guidelines, including only medium and low risk studies in this review. The data for each article were tabulated in a table created in the online word processor "Google Docs". Ten studies met the selection criteria and were included. A total of 37 patients between 9 and 64 years of age were evaluated. The most frequent donor teeth were premolars and third molars. In most cases the patients had no relevant morbid history. Success was evaluated by means of various clinical and radiographic criteria. On the other hand, survival was evaluated during the follow-ups with respect to the permanence of the tooth in the mouth. This type of treatment is not very well known, and the studies included were scarce; on the other hand, they are of a low level of evidence (case reports and case series). The evaluated protocols differ in some characteristics, however, all of them achieve high survival and success rates. There are also some failures, where teeth had to be extracted due to mobility and inflammation.

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

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)

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.

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.

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.

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.

Distancia de la raíz a las tablas óseas y piso nasal de dientes anteriores maxilares con indicación de microcirugía apical / Root to bone table and nasal floor distance of maxillary anterior teeth with indication for apical microsurgery / Tabela raiz-osso e distância do pavimento nasal dos dentes anteriores superiores com indicação para microcirurgia apical

RESUMEN Objetivo: Evaluar la distancia de la raíz a las tablas óseas y piso nasal de dientes anteriores maxilares con indicación de microcirugía apical. Material y métodos: La muestra fue de 44 imágenes tomográficas computarizadas de haz cónico previas al procedimiento de microcirugía apical; además, se seleccionaron 31 imágenes para la comparación con los dientes contralaterales sin indicación de microcirugía apical. Se midió la distancia de la raíz a las tablas óseas y al piso nasal. Resultados: La distancia de la superficie radicular a las tablas óseas vestibular y palatina a 3 mm del ápice fue de 0,98 ± 0,67 mm y 4,26 ± 2,97 mm para el incisivo central; 0,77 ± 0,50 mm y 2,12 ± 1,22 mm para el incisivo lateral; y 0,52 ± 0,63 mm y 5,31 ± 1,38 mm para el canino, respectivamente. La distancia más corta del ápice al piso nasal fue de 9,56 ± 2,88 mm para el incisivo central; 10,33 ± 2,97 mm para el incisivo lateral; y 5,73 ± 2,57 mm para el canino. Solo se encontró una distancia mayor, estadísticamente significativa, del ápice al piso nasal del incisivo lateral con indicación de microcirugía apical en comparación con el incisivo lateral sin indicación de microcirugía apical. Conclusiones: La distancia de la raíz a la tabla ósea vestibular es menor que la distancia de la misma a la tabla ósea palatina. El ápice más próximo al piso nasal fue del canino. Los dientes anteriores maxilares con y sin indicación de microcirugía apical mostraron distancias similares de la raíz a las tablas óseas y piso nasal.

ABSTRACT Objective: To evaluate the distance from the root to the bone tables and nasal floor of maxillary anterior teeth with indication for apical microsurgery. Material and methods : The sample consisted of 44 cone beam computed tomographic images prior to the apical microsurgery procedure; in addition, 31 images were selected for comparison with contralateral teeth without indication for apical microsurgery. The distance from the root to the bone tables and nasal floor was measured. Results: The distance from the root surface to the vestibular and palatal bone tables 3 mm from the apex was 0.98 ± 0.67 mm and 4.26 ± 2.97 mm for the central incisor; 0.77 ± 0.50 mm and 2.12 ± 1.22 mm for the lateral incisor; and 0.52 ± 0.63 mm and 5.31 ± 1.38 mm for the canine, respectively. The shortest distance from the apex to the nasal floor was 9.56 ± 2.88 mm for the central incisor, 10.33 ± 2.97 mm for the lateral incisor, and 5.73 ± 2.57 mm for the canine. A statistically significant greater distance from the apex to the nasal floor was found only for the lateral incisor with indication for apical microsurgery compared to the lateral incisor without indication for apical microsurgery. Conclusions: The distance from the root to the vestibular bone table is less than from the root to the palatal bone table. The apex closest to the nasal floor was that of the canine. Maxillary anterior teeth with and without indication for apical microsurgery showed similar distances from the root to the bone tables and nasal floor.

RESUMO Objetivo: avaliar a distância da raiz às tábuas ósseas e ao assoalho nasal de dentes anteriores superiores com indicação de microcirurgia apical. Material e métodos: a amostra foi composta por 44 imagens de tomografia computadorizada de feixe cônico antes do procedimento de microcirurgia apical; além disso, 31 imagens foram selecionadas para comparação com dentes contralaterais sem indicação de microcirurgia apical. Foi medida a distância da raiz até as tábuas ósseas e o assoalho nasal. Resultados: a distância da superfície radicular às tábuas ósseas vestibular e palatina, a 3mm do ápice, foi de 0,98mm ± 0,67mm e 4,26mm ± 2,97mm para o incisivo central; 0,77mm ± 0,50mm e 2,12mm ± 1,22mm para o incisivo lateral; e 0,52mm ± 0,63mm e 5,31mm ± 1,38mm para o canino, respetivamente. A menor distância entre o ápice e o assoalho nasal foi de 9,56 ± 2,88 mm para o incisivo central; 10,33 ± 2,97 mm para o incisivo lateral; e 5,73 ± 2,57 mm para o canino. Uma distância estatisticamente significativa maior do ápice ao assoalho nasal foi encontrada apenas para o incisivo lateral com indicação de microcirurgia apical em comparação com o incisivo lateral sem indicação de microcirurgia apical. Conclusões: a distância da raiz até a tábua óssea vestibular é menor do que a distância da raiz até a tábua óssea palatina. O ápice mais próximo do assoalho nasal foi o do canino. Os dentes anteriores superiores com e sem indicação de microcirurgia apical apresentaram distâncias semelhantes da raiz às tábuas ósseas e ao assoalho nasal.

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.

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.

Segundo Conducto Mesiovestibular en Molares Superiores: Prevalencia y Análisis Anatómico Mediante Tomografía Computarizada de Haz Cónico / Second Mesiobuccal Canal in Maxillary Molars: Prevalence and Anatomical Analysis Through Cone Beam Computed Tomography

El objetivo de este estudio fue utilizar la Tomografía Computarizada de Haz Cónico (TCHC) para investigar la configuración anatómica, prevalencia y distribución del conducto mesiovestibular Dos (MV2) en molares superiores de una subpoblación chilena, considerando variables como la presencia del conducto MV2, la clasificación de Vertucci, el género y edad. Estudio observacional de corte transversal. La muestra consistió en Tomografías Computarizadas de Haz Cónico tomadas en la clínica odontológica de la Universidad Andrés Bello (Viña del Mar). Se calculó el tamaño muestral utilizando la fórmula de población conocida, lo que resultó en 262 tomografías. Los examinadores se calibraron utilizando el coeficiente Kappa de Cohen, para luego analizar las variables mediante un estudio imagenológico utilizando el software I-CAT Visión. Se analizaron 439 primeros y segundos molares superiores. La prevalencia del conducto MV2 en primeros molares fue del 63,74 %, mientras que, en segundos molares, fue del 20,04 %. La prevalencia en primeros molares fue mayor en hombres (73,86 %) que en mujeres (58,62 %), mientras que, en segundos molares, fue del 15,81 % en mujeres y del 28,41 % en hombres. En relación con la edad, en los primeros molares la diferencia fue significativa en el rango de 18 a 40 años (66,49 %). En cuanto al tipo de configuración según Vertucci (2005), el 70 % de los primeros molares presentó una configuración Tipo II, y un 23,65 % Tipo IV, con resultados similares en los segundos molares. El presente estudio demostró que los conductos MV2 son frecuentes en la población analizada, especialmente en los primeros molares, y que la configuración Tipo II es la más prevalente. Además, se observó una mayor prevalencia en hombres y en el rango de 18 a 40 años. Estos hallazgos proporcionan información relevante sobre la anatomía radicular en la población y pueden contribuir a mejorar los resultados de tratamiento.

SUMMARY: The aim of this study was to use Cone-beam Computed Tomography (TCHC) to investigate the anatomical configuration, prevalence, and distribution of the Second Mesiobuccal (MB2) canal in upper molars of a Chilean subpopulation, considering variables such as the presence of MB2 canal, Vertucci classification, gender, and age. Cross-sectional observational study. The sample consisted of TCHC scans taken at the dental clinic of Universidad Andrés Bello (Viña del Mar). The sample size was calculated using the formula for known population, resulting in 262 scans. The examiners were calibrated using Cohen's Kappa coefficient, then the variables were analyzed through an imaging study using I-CAT Vision software. 439 first and second upper molars were analyzed. The prevalence of MB2 canal in first molars was 63.74 %, while in second molars, it was 20.04 %. The prevalence in first molars was higher in males (73.86 %) than in females (58.62 %), while in second molars, it was 15.81 % in females and 28.41 % in males. Regarding age, in first molars the difference was significant between the age range of 18 to 40 years (66.49 %). Regarding the type of configuration according to Vertucci, 70 % of the first molars had Type II configuration, and 23.65 % had Type IV, with similar results in second molars. The present study demonstrated that MB2 canals are frequent in the analyzed population, especially in first molars, and Type II configuration is the most prevalent. Additionally, a higher prevalence was observed in males and in the age range of 18 to 40 years. These findings provide relevant information about root anatomy in the studied population and can contribute to improving treatment outcomes.