Reabilitação de dente com hipoplasia de turner: relato de caso / Rehabilitation of tooth with Turner's hypoplasia: Case report

Os defeitos de esmalte são alterações qualitativas ou quantitativas na estrutura dentária, que originam-se de fatores sistêmicos, locais ou genéticos. A hipoplasia de Turner é um defeito na espessura do esmalte localizado cuja etiologia decorre de um traumatismo ou infecção periapical presente no dente decíduo predecessor, afetando o desenvolvimento do dente permanente. O objetivo do presente estudo foi apresentar um caso clínico de paciente infantil com dente hipoplásico de Turner em pré-molar, que tornou-se não vital sem que houvesse lesão de cárie ou trauma adicional. Em razão das características clínicas e radiográficas do dente afetado, bem como do risco de cárie e do comportamento cooperador da paciente, optou-se pela reabilitação do elemento afetado por meio de tratamento endodôntico e de restauração semidireta em resina composta. Torna-se de fundamental importância o conhecimento da etiologia e a realização de um exame clínico e radiográfico minucioso visando ao diagnóstico precoce e à elaboração de um plano de tratamento adequado para todos os defeitos de desenvolvimento do esmalte, incluindo-se a hipoplasia de Turner, cujo tratamento dependerá da severidade da alteração, do comportamento do paciente e do risco de cárie. Sugere-se a realização de estudos que associem a microestrutura do esmalte hipoplásico com a ausência de vitalidade pulpar.

Enamel defects are qualitative or quantitative changes in the tooth structure originating from systemic, local, or genetic factors. Turner's hypoplasia is a defect in the thickness of the localized enamel whose etiology arises from trauma or periapical infection in the predecessor deciduous tooth, affecting the permanent tooth's development. The objective of the present study was to present a clinical case of a child patient with a hypoplastic Turner premolar tooth, which became non-vital without the occurrence of caries, or additional trauma. Due to the affected tooth's clinical and radiographic characteristics, the risk of cavities, and the patient's cooperative behavior, it was decided to rehabilitate the affected element through endodontic treatment and semidirect restoration in composite resin. It is of fundamental importance to know the etiology and carry out a thorough clinical and radiographic examination aiming at early diagnosis and the development of an adequate treatment plan for all enamel developmental defects, including Turner's hypoplasia, whose treatment will depend on the severity of the change, the patient's behavior and the risk of caries. Studies are suggested to be carried out that associate the microstructure of hypoplastic enamel with the absence of pulp vitality.

Root Canal Treatment of Mandibular First Premolar with 3 Canals: A Case Report / Tratamiento Endodóntico de Primer Premolar Mandibular con 3 Canales: Reporte de un Caso

SUMMARY: The mandibular first premolar is commonly a single-rooted tooth with occasional presentation of radicular variations. This tooth usually has one root with only one canal (97.9 %). Presence of three canals is very rare. Anomalies may appear during odontogenesis which can lead to anatomical variations in teeth. Similarly, these variations may be associated with characteristics that can be attributed to specific population groups. Due to their low frequency, these additional canals can easily be missed. For this reason, a meticulous knowledge of tooth morphology and their possible anatomical variations are necessary, and the presence of extra roots and canals should be always considered before initiation of root canal treatment. Additionally, different radiographs and appropriated access cavity preparation is needed to ensure a success endodontic treatment. This article reports a diagnosis and endodontic treatment of a mandibular first premolar with three canals.

El primer premolar mandibular suele ser un diente unirradicular con presentación ocasional de variaciones radiculares. Este diente suele tener una raíz con un solo conducto (97,9 %). La presencia de tres canales es muy rara. Durante la odontogénesis pueden aparecer anomalías que pueden provocar variaciones anatómicas en los dientes. De manera similar, estas variaciones pueden estar asociadas con características que pueden atribuirse a grupos de población específicos. Debido a su baja frecuencia, estos canales adicionales pueden pasar desapercibidos fácilmente. Por esta razón, es necesario un conocimiento meticuloso de la morfología dental y sus posibles variaciones anatómicas, y siempre se debe considerar la presencia de raíces y conductos adicionales antes de iniciar el tratamiento de conducto. Además, se necesitan diferentes radiografías y una preparación adecuada de la cavidad de acceso para garantizar un tratamiento de endodoncia exitoso. Este artículo reporta un diagnóstico y tratamiento endodóntico de un primer premolar mandibular con tres canales.

Evaluation of the root morphology of mandibular first premolars using cone-beam computed tomography in a peruvian population / Evaluación de la morfología radicular de primeros premolares mandibulares mediante tomografía computarizada de haz cónico en una población peruana

Introduction: The morphology of the root canal of the first premolars is not always the same and therefore a good knowledge of its dental anatomy is essential. Aim: To assess the morphology of roots and root canals of mandibular first premolars in a Peruvian population using cone-beam computed tomography (CBCT). Materials and Methods: This was a descriptive cross-sec-tional study. A total of 370 mandibular first premolars fulfilling the inclusion criteria were evaluated using CBCT, and the number of roots and root canals, the Vertucci's classification of root canal configuration, age, sex and side of the tooth were registered. Results: One and two roots were presented in 96.2% (n=356) and 3.8% (n=14), respectively, of the mandibular first premolars analyzed, and one canal was present in 67.6% (n=250) and two canals in 32.2% (n=119). A type I root canal configuration was found in 67.6% (n=250) of the cases followed by type V with 26.2% (n=97). A statistically significant association was found between the number of roots and canals (p<0.001) and age also had a significant influence on this variable (p=0.0043). Conclusions: The presence of one canal in mandibular first premolars is the most frequent, although there is a considerable prevalence of two in the population studied. The number of roots is associated with the number of canals, with age having a significant influence on these variables.

Introducción: La morfología del canal radicular de los primeros premolares no siempre es la misma y por ello es fundamental un buen conocimiento de su anatomía dental. Objetivo: Evaluar la morfología de las raíces y conductos radiculares de primeros premolares mandibulares en una población peruana mediante tomografía computarizada de haz cónico. Materiales y Métodos: Este fue un estudio transversal descriptivo. Se evaluaron mediante tomografías un total de 370 primeros premolares mandibulares que cumplían con los criterios de inclusión, y se registró el número de raíces y conductos radiculares, la clasificación de Vertucci de la configuración radicular, la edad, el sexo y el lado del diente. Se realizaron las pruebas de chi-cuadrado y una regresión logística binaria (p<0,05). Resultado: Se presentó una y dos raíces en el 96,2% (n=356) y 3,8% (n=14), respectivamente, de los primeros premolares mandibulares analizados, y un canal estuvo presente en el 67,6% (n=250) y dos canales en el 32,2% (n=119). Se encontró una configuración del conducto radicular tipo I en el 67,6% (n=250) de los casos seguido del tipo V con un 26,2% (n=97). Se encontró una asociación estadísticamente significativa entre el número de raíces y conductos (p<0.001) y la edad también influyó significativamente en esta variable (p=0.0043). Conclusión: La presencia de 1 canal en primeros premolares mandibulares es la más frecuente, aunque existe una prevalencia considerable de 2 en la población estudiada. El número de raíces está asociado al número de canales, teniendo la edad una influencia significativa en estas variables.

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.

Effect of arch shapes and missing second premolars on anchorage during maxillary molar distalization with clear aligners / 中国组织工程研究

BACKGROUND:The reciprocal force generated by the molar distalization with clear aligners can lead to anchorage loss.The effect of arch shapes and missing second premolars on anchorage has not been reported. OBJECTIVE:To analyze the effect of arch shapes and missing second premolars on anchorage during molar distalization with clear aligners using the finite element method. METHODS:Cone-beam CT data from an adult male were acquired from the database to establish the maxilla-upper dentition-periodontium-rectangular attachment-clear aligner model.The distal movement amount designed on the bilateral second molars was set to 0.25 mm.First,there were two groups in the study:second premolar bilateral presence and absence groups.Then,four subgroups in each group were created:tapered arch,ovoid arch,square Class Ⅱ Division 1 arch,and Class Ⅱ Division 2 arch groups.The Ansys software was used to calculate the displacement of the anchorage tooth and the stress of the periodontal ligament. RESULTS AND CONCLUSION:Mesial tipping and extrusion of first molars and premolars,labial inclination and intrusion of anterior teeth occurred during the upper second molar distalization with clear aligners.When the bilateral second premolars were missing,the mesial displacement of first molars increased significantly while that of first premolars and anterior teeth decreased in all groups.The square Class Ⅱ Division 1 arch group showed the least anterior labial inclination,while the tapered arch group showed the most.There was no significant difference between the ovoid arch group and the tapered arch group.Moreover,the magnitude of tipping in the square Class Ⅱ Division 2 arch group was slightly higher than that in the Class Ⅱ Division 1 arch group.The stress of the periodontal ligament of the anchorage teeth was concentrated on the cervical and apical regions of the teeth.And the lowest stress level was detected in the square arch group.Compared with the other groups,the stress on the labial cervical area of the periodontal ligaments was also significantly relieved in the square arch group.To conclude,the square arch is more favorable in terms of anterior anchorage control and periodontal ligament stress distribution.Anterior labial inclination efficiency can be increased in cases of Class Ⅱ Division 2 by designing the anterior labial inclination in conjunction with molar distalization.If the second premolar is missing during molar distalization,it is not conducive to opening up the space in the area of the missing tooth.

Resultados de la técnica ortoradial vs técnica paralela en la identificación de conductos de primeros premolares superiores y primeros molares inferiores

Fundamento: los avances en la imagenología y su implementación en la Odontología permiten lograr mejores tratamientos. Objetivo: describir los resultados de la técnica ortoradial vs técnica paralela en la identificación de conductos de primeros premolares superiores y primeros molares inferiores. Métodos: estudio observacional, descriptivo y transversal en pacientes con necesidad de tratamiento de conductos de primeros premolares superiores o primeros molares inferiores, que acudieron a la Unidad de Atención Odontológica de la Universidad Regional Autónoma de los Andes en el periodo abril-agosto de 2019. La muestra la constituyeron 62 pacientes, separados en dos grupos: premolares superiores (n=30) o primeros molares inferiores (n=32) y ambos en otros dos grupos según técnica empleada (técnica paralela y técnica ortoradial). Resultados: en los primeros premolares superiores la técnica ortoradial mostró mejores resultados que la paralela para obtener imágenes precisas (100 % vs. 20 %). En los primeros molares inferiores, la técnica ortoradial mostró resultados superiores a la técnica paralela para el conducto mesiolingual (93,75 % vs 31,25 %) y conducto disto lingual (31,25 % vs 12,5 %). La elongación de las raíces predominó en la técnica ortoradial (n=8), al igual que la superposición dental (n=10). Conclusiones: la técnica ortoradial mostró resultados superiores al momento de localizar tanto el conducto vestibular y palatino en los primeros premolares superiores como para el conducto mesiolingual y el conducto distolingual. La elongación de las raíces se observó en mayor cuantía en la técnica ortoradial, al igual que la superposición dental.

Foundation: advances in imaging and its implementation in Dentistry allow for better treatments. Objective: to describe the results of the orthoradial technique vs parallel technique in the identification of upper first premolars canals and lower first molars. Methods: observational, descriptive and cross-sectional study in patients in need of root canal treatment of upper first premolars or lower first molars, who attended the Dental Care Unit of the Andes Regional Autonomous University from April to August 2019. The sample consisted of 62 patients, separated into two upper premolar groups (n=30) or lower first molars (n=32) and both into two other groups according to the technique used (parallel technique and orthoradial technique). Results: in the upper first premolars, the orthoradial technique showed better results than the parallel technique to obtain accurate images (100% vs. 20%). In the lower first molars, the orthoradial technique showed superior results to the parallel technique for the mesiolingual canal (93.75% vs 31.25%) and distolingual canal (31.25% vs 12.5%). Root elongation predominated in the orthoradial technique (n=8), as did dental overlap (n=10). Conclusions: the orthoradial technique showed superior results when locating both the buccal and palatine canal in the upper first premolars and for the mesiolingual canal and the distolingual canal. Root elongation was observed to a greater extent in the orthoradial technique, as was dental overlap.

CBCT study of root apices distance to mandibular canal in peruvian population

The purpose of this study was to compare the average distances from the root apices of the first molars, second molars, and second premolars to the mandibular canal according to sex in the Peruvian population using cone-beam computed tomography (CBCT). Eighty CBCT scans of Peruvian patients aged from 15-80 years were examined. After locating the mandibular canal, measurements of the vertical distances from the mandibular canal to the apices of the second premolars, as well as the first molars and second molars, were made. For the statistical analysis, Student's t test was used for both paired and unpaired samples, with a significance level of p0.05) between the distances from the apices of the second premolars and the first and second molars to the mandibular canal. However, for the second premolars and second molars on the left side, the values were higher, with averages of 5.52mm and 3.75mm, respectively. The mesial roots of the second molars were closer to the mandibular canal. In addition, women showed shorter distances than men.

El propósito de este estudio fue comparar las distancias promedio desde los ápices radiculares de primeros molares, segundos molares y segundos premolares al canal mandibular según sexo en la población peruana mediante tomografía computarizada de haz cónico (TCHC). Se examinaron 80 tomografías CBCT de pacientes peruanos con edades comprendidas entre los 15 y 80 años. Luego de ubicar el canal mandibular, se realizaron mediciones de las distancias verticales desde el canal mandibular hasta el ápice de los segundos premolares mandibulares, así como de los primeros molares y segundos molares. Para el análisis estadístico se utilizó la prueba t de Student para muestras pareadas y no pareadas con un nivel de significación de p0.05) entre las distancias desde los ápices de los segundos premolares mandibulares y los primeros y segundos molares al canal mandibular. Sin embargo, para los segundos premolares y segundos molares en el lado izquierdo, los valores fueron más altos con un promedio de 5,52mm y 3,75mm, respectivamente. Las raíces mesiales de los segundos molares estaban más cerca del canal mandibular. Además, las mujeres mostraron distancias más cortas que los hombres.

Study of anatomical variations in premolars by cone beam computerized tomography in a radiologic clinic in Piauí / Estudo de variações anatômicas em pré-molares por tomografia computadoriza de cone beam em uma clínica radiológica no Piauí

Introduction: Root canal cleaning is the main objective of endodontic treatment and requires knowledge of the internal anatomy. The premolars are evidenced in the literature with great anatomical variations. In view of this, studies indicate that the use of Cone Beam Computed Tomography helps in the visualization of highly complex anatomy. Objective: to describe the anatomical variations in maxillary and mandibular premolars using cone beam computed tomography in a radiologic clinic in Piaui. Methods: 54 cone beam computed tomography scans with 160 premolars were used, produced using the Orthopantomograph OP300 equipment and analyzed by multiplanar reconstructions: axial, coronal and sagittal. Data regarding sex, number of roots and canals were recorded to compare and classify according to Vertucci. Results: the maxillary first pre-molars had 63.5% two roots,83.7% with one root and the mandibular pre-molars mostly with one root. Regarding the number of channels, 92.3% of the first premolars had two channels, most of them maxillary second premolars and mandibular premolars only one channel. Vertucci variations of types I, II, III and IV were verified in single-rooted elements, observing a great variation in superior elements. As for the prevalence of sex, only the first superiors showed greater variation in males. Conclusions: the upper first premolars prevailed with a great anatomical variation in relation to the other premolars with prevalence of Vertucci Type I and in males.

Introdução: a limpeza do canal radicular é o principal objetivo do tratamento endodôntico e requer conhecimento da anatomia interna. Os pré-molares são evidenciados na literatura com grandes variações anatômicas. Diante disso, estudos indicam que o uso da Tomografia Computadorizada Cone Beam auxilia na visualização de anatomias de alta complexidade. Metodologia: foram utilizadas 54 tomografias computadorizadas de feixe cônico com 160 pré-molares, produzidas no equipamento Orthopantomograph OP300 e analisadas por reconstruções multiplanares: axial, coronal e sagital. Os dados referentes ao sexo, número de raízes e canais foram registrados para comparação e classificação segundo Vertucci. Resultados: os primeiros pré-molares superiores apresentavam 63,5% de duas raízes, 83,7% dos segundos pré-molares superiores tinham uma raiz e a maioria dos pré-molares inferiores tinha uma raiz. Em relação ao número de canais, 92,3% dos primeiros pré-molares possuíam dois canais, sendo a maioria segundos pré-molares superiores e pré-molares inferiores apenas um canal. Vertucci variações dos tipos I, II, III e IV foram verificadas nos elementos uniradiculares, observando-se a grande variação nos elementos superiores. Quanto à prevalência do sexo, apenas os primeiros superiores apresentaram maior variação no sexo masculino. Conclusão: os primeiros pré-molares superiores prevaleceram com grande variação anatômica em relação aos demais pré-molares com prevalência de Vertucci Tipo I e no sexo masculino.

Resistencia a la fractura de premolares superiores con tratamientos de endodoncia por accesos conservador y tradicional / Resistance to Fracture of Upper Premolars with Endodontic Treatment by Conservative and Traditional Access

Introducción: Las piezas dentarias luego de tratamiento de endodoncia aumentan su susceptibilidad a la fractura, lo que está asociado, principalmente, con la pérdida de la estructura dental. Objetivo: Evaluar in vitro, la resistencia a la fractura de premolares superiores con tratamientos de endodoncia mediante acceso tradicional, conservador y conservador Ninja, con restauración provisoria y final. Métodos: Estudio prospectivo de diseño experimental longitudinal con 42 premolares superiores donados, separados en 3 grupos según el tipo de acceso de endodoncia a aplicarse y luego cada uno en dos subgrupos según el tipo de restauración, y un grupo control, al cual no se le realiza endodoncia. Luego de realizar el tratamiento y la restauración, se evaluó la resistencia a la fractura mediante carga compresiva oblicua (45°), en una máquina de carga universal. Las cargas requeridas para la fractura se registraron en newtons y fueron comparadas estadísticamente. Resultados: Las piezas tratadas mediante acceso conservador Ninja con restauración provisoria y final, requirieron una carga promedio para la fractura de 513,45 N y 638,13 N, respectivamente. Fuerzas significativamente mayores a las resistencias ofrecidas por los otros tratamientos con p 0,05. Conclusiones: En la endodoncia in vitro, el diseño del acceso a la cavidad, tipo conservador Ninja, afectó significativamente la resistencia a la fractura de los premolares superiores, adquiriendo un comportamiento biomecánico similar al de las piezas control(AU)

Introduction: Tooth pieces, after endodontic treatment, increase their susceptibility to fracture, a phenomenon mainly associated with loss of tooth structure. Objective: To evaluate, in vitro, the resistance to fracture of upper premolars with endodontic treatment by traditional, conservative and conservative ninja access, with temporary and final restoration. Methods: A prospective study of longitudinal experimental design was carried out with 42 donated upper premolars, separated into three groups, according to the type of endodontic access to be applied; in turn, each was then divided into two subgroups, according to the type of restoration, and a control group, not performed endodontic treatment. After treatment and restoration, fracture resistance was evaluated using oblique compressive loading (45°) in a universal loading machine. The loads required for fracture were recorded in newtons and statistically compared. Results: The parts treated by conservative ninja access with provisional and final restoration required an average fracture load of 513.45 N and 638.13 N, respectively; this forces were significantly higher than the resistance values offered by the other treatments, with p < 0.05. Likewise, there were no significant differences in the resistance values obtained between the cases of conservative access and traditional access, nor when comparing the types of applied restoration, with P<0.05. Conclusions: In in vitro endodontics, the design of the access to the cavity of conservative ninja type significantly affected the resistance to fracture of the upper premolars, acquiring a biomechanical behavior similar to that of the control pieces(AU)

Study of tooth drifts after orthodontic extractions in cases of interruption / 口腔疾病防治

Objective @# To compare the tooth drift differences between different types of patients after orthodontic extraction for 1.5 months (45 days) without return to the clinic on time for some reasons.@*Methods@#This study has been reviewed and approved by the Ethics Committee, and informed consent has been obtained from patients. A total of 84 patients had bilateral premolars extracted but were not bonded the bracket for some reasons. The upper and lower jaw dental models were cast, scanned, and reconstructed in 3D. Patients were divided into 12 groups based on extraction positions (first premolar or second premolar), jaw types (maxilla or mandible) and vertical facial types (average angle, high angle, or low angle). Multivariate analysis of variance was used to analyze the changes in the following five indicators in different types of patients who were interrupted for 1.5 months after extraction: anterior tooth crowding, width between canines, width between first molars, tooth extraction space, and overbite of anterior teeth. @*Results @#The tooth extraction position, jaw type and vertical facial type had an effect on the reduction in tooth extraction space and anterior tooth crowding before and after the sudden emergent state (1.5 months after tooth extraction) (P<0.001), and the tooth extraction position and vertical facial type had an effect on the increase in anterior tooth overbite (P<0.001). The drift of bilateral adjacent teeth was greater in patients with first premolars extracted than in those with second premolars extracted (P<0.001), and the drift of bilateral adjacent teeth in the maxilla was larger than that of the mandible (P<0.001). The drift of bilateral adjacent teeth in patients with high angles was more obvious than that of patients with average angles and low angles (P<0.001). @* Conclusion@# For orthodontic patients who have maxillary tooth extraction, first premolar extraction, and even high angles in the vertical facial type, the bilateral adjacent teeth are easier to drift, orthodontic treatment should be carried out soon after extraction, and attention should be given to anchorage control.

Diferencias en el abordaje de dos premolares inferiores con dens evaginatus: reporte de caso / Diferencas na abordagem de dois pré-molares inferiores com dens evaginatus: relato de caso / Differences in the approach of two lower premolars with dens evaginatus: case report

El dens evaginatus es una anomalía dentaria de forma que consiste en una elevación del esmalte en forma de cúspide o tubérculo que se ubica en el surco central o en la zona bucal de las cúspides de premolares o molares, así como en las superficies palatinas de dientes anteriores. La estructura interna del tubérculo está formada por una capa de esmalte que recubre un núcleo de dentina el cual contiene, en el 90% de los casos una evaginación de tejido pulpar. En este artículo se reporta el caso de un paciente de ascendencia asiática con dos premolares inferiores con dens evaginatus las cuales fueron abordadas de diferente forma: una premolar recibió tratamiento preventivo y mínimamente invasivo mientras que la otra premolar requirió un tratamiento pulpar

Dens evaginatus é uma anormalidade dentaria que consiste em uma elevação do esmalte em forma de cúspide ou tubérculo que se localiza no sulco central ou na zona bucal das cúspides de pré-molares ou molares, bem como nas superficies palatinas dos dentes anteriores. A estructura interna do tubérculo é formada por uma camada de esmalte que recobre um núcleo de dentina que contém, em 90% dos casos, uma evaginação de tecido pulpar. Neste artigo relata o caso de um paciente de ascendência asiática com duas pré-molares inferiores com dens evaginatus, que foram abordados de forma diferente: um pré-molar recebeu tratamento preventivo e minimamente invasivo enquanto a outra pré-molar necessitou de tratamento pulpar

Dens evaginatus is a dental abnormality consisting of a cusp- or tubercle-shaped elevation of the enamel that is in the central groove or in the buccal area of the cusps of premolars or molars, as well as on the palatal surfaces of teeth. The internal structure of the tubercle is formed by a layer of enamel that covers a core of dentin which contains, in 90% of cases, an evagination of pulp tissue. This article reports the case of a patient of Asian descent with two lower premolars with dens evaginatus, which were approached differently: one premolar received preventive and minimally invasive treatment while the other premolar required root canal treatment.

MANDIBULAR PREMOLAR WITH TWO ROOTS AND TWO ROOT CANALS: A CASE REPORT.

For the success of a root canal treatment, an in-depth knowledge of pulpal anatomy and its variations are essential. Failure to perform thorough debridement and improper obturation will lead to reinfection of the root canal, which will adversely affect the treatment outcome. Mandibular premolars usually have single root with single root canal system. Howeveranatomic variations of mandibular premolar have been reported. The clinician should be aware of the configuration of the pulp system for the successful endodontic treatment. The incidence of two roots in these teeth is quite rare. This report presents the clinical management of mandibular premolar having two roots bifurcated at the mid-root level

Root and root canal system morphology of maxillary first premolars in a Chilean subpopulation: a cone-beam Computed Tomography Study / Morfología radicular y del sistema de canales radiculares de los primeros premolares maxilares en una subpoblación chilena: un estudio de tomografía computarizada de haz de cono

SUMMARY: The maxillary first premolar (MFP) presents a highly variable and complex root morphology; it is also one of the teeth most likely to suffer vertical root fractures. The aim of this study was to describe the morphology of the root and root canal system of the MFP in a Chilean population using Cone-Beam Computed Tomography (CBCT). One hundred and twenty-one MFP were evaluated (60 left and 61 right), belonging to subjects of both sexes. Descriptive and statiscal analysis of the data was carried out, with a value of P < 0.05 being statistically significant. One root was observed in 71 % of teeth and two roots in 29 %; statistically significant differences were observed in the number of roots by sex (p<0.05). Two root canals were found in 69.5 % of teeth and one canal in 30.5 %. In terms of morphological classification, 41.3 % of cases were Vertucci Type IV. The proximal cementodentinal walls were the thinnest. The MFP presented a high degree of morphological variation in a Chilean subpopulation.

RESUMEN: El primer premolar maxilar (PPM) presenta una morfología radicular muy variable y compleja; también es uno de los dientes con mayor probabilidad de sufrir fracturas radiculares verticales. El objetivo de este estudio fue describir la morfología de la raíz y el sistema de conductos radiculares del PPM en una población chilena mediante tomografía computarizada de haz cónico (CBCT). Se evaluaron 121 PPM (60 izquierdas y 61 derechas), pertenecientes a sujetos de ambos sexos. Se realizó un análisis descriptivo y estadístico de los datos, siendo estadísticamente significativo un valor de P < 0,05. Se observó una raíz en el 71 % de los dientes y dos raíces en el 29 %; se observaron diferencias estadísticamente significativas en el número de raíces por sexo (p<0.05). Se encontraron dos conductos radiculares en el 69,5 % de los dientes y un conducto en el 30,5 %. En cuanto a la clasificación morfológica, el 41,3 % de los casos fueron Vertucci Tipo IV. Las paredes cementodentinales proximales fueron las más delgadas. El PPM presentó un alto grado de variación morfológica en una subpoblación chilena.

Evaluación de zonas de esfuerzo entre implante personalizado sinterizado e implante prefabricado mediante fotoelasticidad / Evaluation of effort zones between custom implant sinterized and the prefabricated implant though photoelasticity

Resumen Introducción: el uso de implantes personalizados es un tratamiento utilizado con mayor frecuencia, valorando y comparando su comportamiento frente a implantes convencionales. Este estudio tuvo como objetivo analizar si las zonas de esfuerzo del implante personalizado son diferentes a las que presenta el implante prefabricado convencional mediante fotoelasticidad. Métodos: muestra n=10 dientes premolares superiores, n=10 implantes personalizados sinterizados y n=10 implantes prefabricados convencionales, sometidos a 3 presiones fijas y controladas, observados a través de un polariscopio para analizar la distribución del esfuerzo generados. Resultados: zonas de esfuerzo presentes en las diferentes muestras analizadas aplicando 3 presiones. La cantidad de esfuerzo en la presión 1 (test de Chi-cuadrado, p=0,596) es diferente entre los dos tipos de implantes al igual que con la presión 2 (test de Chi-cuadrado, p=0,407), al aplicar la presión 3 (test de Levene, p=0,899) no hay diferencia en la distribución de fuerzas entre los dos tipos de implantes. Conclusiones: se determinó que el implante prefabricado convencional distribuye y concentra mejor el esfuerzo generado bajo diferentes presiones en comparación con el implante personalizado sinterizado.

Abstract Introduction: the use of custom implants is a very common treatment; we assess and compare their behavior against that of conventional implants. This study aimed to make sure that the stress zones of the custom implant are different from those presented by the conventional prefabricated implant by photoelasticity. Methods: we subjected samples of n=10 bicuspid teeth, n=10 sintered custom implants, and n=10 conventional prefabricated implants to 3 fixed and controlled forces and observed the samples through a polariscope to analyze the distributions of effort generated. The effort zones present in the different samples were analyzed under 3 different forces. Results: the amounts of effort in the two types of implants under force 1 (chi-square test, p=0.596) are different, as is also the case under force 2 (chi-square test, p=0.407). Under force 3 (Levene test, p=0.899), there is no difference in the distributions of effort between the two types of implants. Conclusions: it was determined that the conventional prefabricated implant distributes and concentrates the effort generated under different forces better than the sintered custom implant.

Comportamiento de las lesiones cervicales no cariosas en pacientes de la clínica estomatológica de Jimaguayú / Behavior of non-carious cervical lesions in patients from the dental clinic of the Jimaguayú municipality

RESUMEN Fundamento: las lesiones cervicales no cariosas son aquellas que se producen por la pérdida de tejido dental debido a causas diferentes de la bacteriana. Las mismas han ganado la atención de investigadores debido a la alta prevalencia con la que se han presentado. Objetivo: describir el comportamiento de las lesiones cervicales no cariosas en pacientes de la clínica estomatológica del municipio Jimaguayú en la provincia Camagüey. Métodos: se realizó un estudio descriptivo observacional analítico y transversal. Se tuvo como población de estudio a 54 pacientes de 20 años y más que presentaron lesiones cervicales no cariosas, se tomaron en consideración variables tales como: sexo, tipo de lesión, factores de riesgo y grupos dentarios afectados. Resultados: las personas mayores de 60 años fueron las más afectadas por este tipo de lesiones. Los hombres prevalecieron con relación a las mujeres, las que a su vez fueron más afectadas por las abfracciones. El factor de riesgo más asociado al origen de estas enfermedades fue la técnica de cepillado incorrecta y se tuvo en cuenta que en un mismo paciente pudieron incidir más de un factor de riesgo. Los premolares fueron los dientes más afectados y en menor medida los incisivos. Conclusiones: se deben considerar a las lesiones cervicales no cariosas como un problema de salud de origen multifactorial y con una clara repercusión sobre la integridad de los tejidos dentarios.

ABSTRACT Background: non-carious cervical lesions are those that are produced by the loss of dental tissue due to causes other than bacterial. They have gained the attention of researchers due to the high prevalence with which they have been presented. Objective: to describe the behavior of non-carious cervical lesions in patients from the dental clinic of the Jimaguayú municipality of Camagüey. Methods: descriptive, observational, analytical and cross-sectional study was carried out with 54 patients of 20 years old and older who presented non-carious cervical lesions as the study population, taking into consideration variables such as sex, type of lesion, risk factors and affected dental groups. Results: people over 60 years of age were the most affected by this type of injury. Men prevailed in relation to women, who in turn were more affected by abfractions. The risk factor most associated with the origin of these pathologies was the incorrect brushing technique and it was taken into account that more than one risk factor could have an impact on the same patient. The premolars were the teeth most affected and to a lesser extent the incisors. Conclusions: non-carious cervical lesions should be considered as a health problem of multifactorial origin and with a clear repercussion on the integrity of the dental tissues.

Mandibular pre-molars endodontic anatomy and role in sex dimorphism for Western Asia population using CBCT 3d imaging technique / Anatomía endodóntica de premolares mandibulares y papel en el dimorfismo sexual para la población de Asia Occidental utilizando la técnica de imagen 3d CBCT

SUMMARY: Cone Beam Computerized Tomography (CBCT) imaging technique can be used for identifying the root canal anatomy and its use in determining sexual dimorphism. The aim of current study was to identify the commonly found root canal morphology and gender dimorphism for mandibular pre-molars in Western Asia population according to Vertucci's classification using CBCT 3D imaging technique. On ethical approval 470 patients from Western Asia population with intact healthy mandibular first and second pre-molars were included in the study. The selected patients were sent to radiology department of Riyadh Elm University, Saudi Arabia for CBCT images. The observations recorded included: i) number of roots; and ii) type of root canal morphology based on Vertucci's classification. All the mandibular first and second pre-molars had single root both in males and females. The type of Vertucci's classification commonly observed was Type I both in males (88.94 %) and females (100 %) in mandibular first pre-molars. Similarly Type I was identified as a common root canal configuration in mandibular second pre-molars for males (82.77 %) and females (100 %). The two canal configurations Type IV and V were only observed in the males. It can be concluded from the results mandibular first and second pre-molars in the Western Asia population are single rooted with common Vertucci's Type I canal configuration in the females with rare evidence of two canals in males. Additionally CBCT is an effective technique and should be used for detection of root canals in the mandibular pre-molars which can aid dentists in providing a successful endodontic therapy.

RESUMEN: La imagen de la tomografía computarizada de haz cónico (CBCT) se puede utilizar para identificar la anatomía del conducto radicular y para determinar el dimorfismo sexual. El objetivo del estudio fue identificar la morfología del conducto radicular y el dimorfismo de sexo, comúnmente encontrados en los premolares mandibulares en la población de Asia occidental, de acuerdo con la clasificación de Vertucci, utilizando la técnica de imágenes CBCT 3D. Tras la aprobación ética, se incluyeron en el estudio 470 pacientes de la población de Asia occidental con primeros y segundos premolares mandibulares sanos intactos. Los pacientes seleccionados fueron enviados al departamento de radiología de la Universidad de Riyadh Elm, Arabia Saudita, para las imágenes CBCT. Las observaciones incluyeron: i) número de raíces; y ii) tipo de morfología del conducto radicular según la clasificación de Vertucci. Se observó solamente una raíz en los primeros y segundos premolares mandibulares tanto en hombres como en mujeres. El tipo de clasificación de Vertucci comúnmente observado fue Tipo I tanto en hombres (88,94 %) como en mujeres (100 %) en los primeros premolares mandibulares. El Tipo I se identificó como una configuración común del conducto radicular en los segundos premolares mandibulares para hombres (82,77 %) y mujeres (100 %). Ambas configuraciones de canal Tipo IV y V solo se observaron en los varones. Se puede concluir a partir de los resultados de los primeros y segundos premolares mandibulares en la población de Asia occidental, que éstos tienen una sola raíz con una configuración de canal de Vertucci Tipo I común en mujeres con una evidencia de dos canales infrecuente en los hombres. La CBCT es una técnica eficaz y debe usarse para la detección de conduc- tos radiculares en los premolares mandibulares, lo que puede ayu- dar a los dentistas a proporcionar una terapia endodóntica exitosa.

Esfuerzos generados en la ATM en maloclusión clase II, tratada con exodoncias de premolares y ortodoncia: análisis mediante el método de elementos finitos / Strain generated in the TMJ with class II malocclusions, treated with extraction of premolars and orthodontics: analysis with the finite element method

RESUMEN Introducción: la exodoncia de premolares es una alternativa para el tratamiento de la maloclusión clase II. Un cambio en la biomecánica puede generar alteraciones en la Articulación Temporomandibular (ATM) lo que produce mayor desgaste dental y aparición de patologías articulares. El objetivo fue analizar mediante el método de elementos finitos la concentración de esfuerzos en la ATM, en maloclusión clase II, tratados con exodoncia de premolares y Ortodoncia. Métodos: dos modelos de simulación en 3D cada uno con estructuras óseas de los 2 maxilares, dentición completa y disco en la ATM. Uno corresponde al paciente sin recidiva (SR) tratado con exodoncia de primeros premolares y ortodoncia, donde se mantiene la estabilidad dental clase I. El otro modelo con recidiva (CR) tratada con exodoncia de primeros premolares y ortodoncia, aumento de overjet y overbite y clase II canina; la carga se aplicó sobre la rama mandibular. Resultados: con una carga de 900N los esfuerzos se triplicaron en todas las estructuras de los dos modelos al ser comparados con una carga de 300N; sin embargo, se dieron diferencias considerables en el modelo CR entre las cavidades glenoideas, a 300N de 19.9 MPa y a 900N de 59.3 MPa. La mayor concentración del disco se da en la parte lateral. Conclusiones: dada la asimetría en las estructuras de la ATM, los esfuerzos y la concentración de tensiones difieren entre el lado derecho e izquierdo en los dos modelos.

Abstract Introduction: premolar extraction is an alternative for the treatment of class II malocclusion. A change in biomechanics can generate alterations in the Temporomandibular Joint (TMJ), which produces greater dental wear and the appearance of joint dysfunctions. The objective was to assess the effort concentration in the TMJ by means of finite element analysis in class II malocclusions treated with premolar extraction and orthodontics. Method: two 3D simulation models each with bone structures of the 2 jaws, complete dentition and disc in the TMJ. One corresponds to the patient without recurrence (WR) treated with extraction of first premolars and orthodontics, where class I dental stability is maintained. The other model with recurrence (R) treated with extraction of first premolars and orthodontics, increased overjet and overbite and canine class II; the load was applied to the mandibular ramus. Results: loads of 900N triplicated on all structures compared to 300N in both models. However, there were considerable differences between the left and right glenoid cavities in the WR model, at 300N of 19.9 MPa and 900N at 59.3 MPa. Most tensions of the disc occur in the lateral part. Conclusions: due to the asymmetry in the TMJ structures, the stresses and stress concentration differ between the right and left sides in the two models.

Root anatomy and canal configuration of maxillary premolars: a cone-beam computed tomography study / Anatomía de la raíz y configuración del conducto de los premolares maxilares: estudio de tomografía computarizada de haz cónico

SUMMARY: The aim of the study was to determine the number and anatomical configuration of roots and root canals of maxillary first and second premolars using cone-beam computed tomography scans. n273 CBCT scans were evaluated, obtaining a sample of 592 maxillary premolars. Root number and root canal anatomy were categorized using Ahmed´s classification. Data was analyzed using Pearson's Chi-squared test. Two roots were present on 157 first premolars, one root in 132 premolars and three roots in 17. Second premolars presented one root in 266 samples and two roots in 20; no second premolars presented three roots. Eight different configurations were found; the most frequent was 2MP B1 P1 in first premolars (51,3 %) and 1MP1 (63.6 %) in second premolars. The most frequent morphology found in maxillary premolars in Chilean population was two and three roots. The analysis of internal anatomy using CBCT revealed a highly variable distribution of root canals, generally of low to medium complexity, similar to what is found in other ethnic groups.

RESUMEN: El objetivo de este estudio fue determinar el número y la configuración de raíces y canales radiculares de primeros y segundos premolares maxilares utilizado tomografía computacional de haz cónico. 273 TCHC fueron evaluados, obtenido una muestra de 592 premolares maxilares. El número de raíces y la anatomía de los canales radiculares fueron categorizados utilizando la clasificación de Ahmed. Los datos fueron analizados con la prueba Chi- Cuadrado de Pearson. Dos raíces fueron observadas en 157 primeros presentaron una raíz en 266 muestras y dos raíces en 20; no se encontraron tres raíces en segundos premolares. Ocho diferentes configuraciones fueron encontradas; siendo la más frecuente 2MP B1 P1 en primeros premolares (51,3 %) y 1MP1 (63,6 %) en segundos premolares. La morfología radicular más frecuentemente encontrada en premolares de población Chilena fue de dos y tres raíces. El análisis de la anatomía interna usando TCHC mostró una gran variabilidad de en la distribución de los canales radiculares. Generalmente de mediana y baja complejidad como los encontrados en otros grupos etnicos.

Caracterización de lesiones cervicales no cariosas en pacientes bruxópatas / Characterization of non-carious cervical lesions in bruxopathic patients

RESUMEN 20. Fundamento: las lesiones cervicales no cariosas son la pérdida patológica del tejido dentario, donde el bruxismo juega un rol importante como factor de riesgo que al transmitir fuerzas lesivas provoca la fractura de los tejidos dentarios y la posterior afectación estética. Objetivo: caracterizar las lesiones cervicales no cariosas en pacientes bruxópatas. Métodos: se realizó un estudio descriptivo, transversal en los pacientes atendidos en la consulta de Prótesis Estomatológica del municipio Nuevitas, provincia Camagüey en el período de enero a julio de 2019, el universo lo constituyeron los 157 pacientes diagnosticados con bruxismo, que presentaran al menos un tipo de las lesiones cervicales no cariosas, la muestra fue de tipo probabilístico por el método aleatorio simple y quedó constituida por 97 pacientes. Resultados: de los pacientes bruxópatas examinados con lesiones cervicales no cariosas predominó el sexo femenino y el grupo de edad entre 34 a 48 años. La principal lesión cervical no cariosa de forma general en los pacientes con bruxismo fue la abfracción y se relacionó con mayor frecuencia en los pacientes con bruxismo de rechinamiento. El grupo dentario de premolares superiores fueron los más afectados. Conclusiones: durante la caracterización de las lesiones cervicales no cariosas en el paciente con bruxismo, predominó el sexo femenino y entre la tercera y cuarta década de vida, la abfracción fue la principal lesión cervical no cariosa, de mayor frecuencia en el bruxismo por rechinamiento y el grupo dentario premolar el más afectado.

ABSTRACT 27. Background: non-carious cervical lesions are the pathological loss of dental tissue, where bruxism plays an important role as a risk factor that, by transmitting damaging forces, causes the fracture of dental tissues and subsequent aesthetic involvement. Objective: to characterize non-carious cervical lesions in bruxopathic patients. Methods: a descriptive, cross-sectional study was carried out in the patients treated at the dental prosthesis consultation of the Nuevitas municipality, Camagüey province in the period from January to July 2019, the universe was made up of 157 patients diagnosed with bruxism, who presented at least a type of non-carious cervical lesions, the sample was probabilistic by the simple random method, and consisted of 97 patients. Results: of the bruxopathic patients examined with non-carious cervical lesions, the female sex and the age group between 34 and 48 years predominated. The main non-carious cervical lesion in general in patients with bruxism was abfraction and was more frequently associated in patients with grinding bruxism. The dental group of upper premolars were the most affected. Conclusions: during the characterization of non-carious cervical lesions in the patient with bruxism, the female sex predominated and between the third and fourth decade of life, abfraction was the main non-carious cervical lesion, with the highest frequency in grinding bruxism and the premolar dental group the most affected.

Influence of base materials on stress distribution in endodontically treated maxillary premolars restored with endocrowns / 北京大学学报(医学版)

OBJECTIVE@#To evaluate the influence of base materials on stress distribution in endodontically treated maxillary premolars restored with endocrowns using three-dimensional finite element analysis.@*METHODS@#A maxillary second premolar was scanned by Micro-CT and a three-dimensional finite element model of ceramic endocrown with 1 mm thickness of base was established. A model without base was also established as a negative control. Four kinds of conventional base materials with different elastic modulus were adopted: light cure glass ionomer(3M Vitrebond, 3 657 MPa), flowable composite resin(3M Filtek Z350XT Flowable Restorative, 7 300 MPa), high strength glass ionomer(GC Fuji Ⅸ, 13 130 MPa), and posterior composite resin(3M Filtek P60, 19 700 MPa). With a 200 N force loaded vertically and obliquely, the distribution and magnitude of stress in the tooth tissue and adhesive layer were investigated by three-dimensional finite element analysis.@*RESULTS@#The maximum von Mises stress values(vertical/oblique) in dentin and adhesive layer were measured as follows: (1) no base material: 19.39/70.49 MPa in dentin and 6.97/17.97 MPa in adhesive layer; (2) light cure glass ionomer: 19.00/69.75 MPa in dentin and 6.87/16.30 MPa in adhesive layer; (3) flowable composite resin: 18.78/69.33 MPa in dentin and 6.79/16.17 MPa in adhesive layer; (4) high strength glass ionomer: 18.71/69.20 MPa in dentin and 6.74/16.07 MPa in adhesive layer; (5) posterior composite resin: 18.61/69.03 MPa in dentin and 6.70/16.01 MPa in adhesive layer. Under the same loading condition, models with different elastic moduli of base materials had similar stress distribution patterns. The von Mises stress of tooth tissue was mainly concentrated in the tooth cervix. Under oblique load, the regions where von Mises stress concentrated in were similar to those under a vertical load, but the values increased. The stress concentration in the tooth cervix was alleviated in models with base materials compared with the model without base material. The maximum von Mises stress in the tooth tissue and adhesive layer decreased when the elastic modulus of base materials increased and got close to that of dentin.@*CONCLUSION@#The posterior composite resin of which the elastic moduli is high and close to that of dentin is recommended as base material for premolar endocrowns to alleviate the concentration of stress in tooth cervix and adhesive layer.