Elaboración de modelos dentales didácticos en resina epóxica / Elaboration of didactic dental models in epoxy resin

Los modelos de estudio son un registro fundamental para el diagnóstico, el plan de tratamiento, la presentación de caso y la evaluación del progreso del tratamiento dental; son registros anatomofisiológicos de las arcadas dentarias que sirven para evaluar la dentición en los tres planos del espacio y la oclusión en la relación cúspide-fosa, en una dimensión estática y dinámica. Para obtener los modelos de estudio es imprescindible obtener impresiones totales con diversos materiales de impresión de los arcos dentarios, que reproduzcan fielmente todos los detalles anatómicos, para posteriormente obtener un modelo en yeso piedra. Los modelos obtenidos a partir de una impresión generalmente son a base de yeso odontológico, los cuales a pesar de sus mejoras aún conservan algunas características negativas como: baja resistencia a la fractura por impacto, baja resistencia al desgaste por abrasión, inestabilidad dimensional y radiopacidad que impide la simulación de procedimientos endodóncicos. Con la finalidad de mejorar la simulación en la práctica odontológica, se usa la resina epóxica que puede emplearse en la obtención de modelos, este material es más resistente y presenta una mayor resistencia a la abrasión; además es radiolúcido, por lo que es útil para la réplica de preparaciones y procedimientos de simulación endodóntica. Los detalles de la superficie obtenidos con resina epóxica son superiores a los obtenidos con yeso. El uso de simuladores es una herramienta educativa con la que se favorece la adquisición de ciertas habilidades, destrezas, técnicas y competencias necesarias para la formación de estudiantes o profesionales de odontología. En el presente trabajo se describe la técnica para la elaboración de modelos dentales didácticos en resina epóxica para utilizarlos en la enseñanza de la práctica odontológica (AU)

Study studies are a fundamental record for diagnosis, treatment plan, case presentation and evaluation of the progress of dental treatment. They are anatomo-physiological records of the dental arches to evaluate the dentition in the three planes of space and the occlusion in the cusp-fossa relationships, in a static and dynamic dimension. To obtain the study models, it is essential to obtain total impressions with various impression materials of the dental arches, which faithfully reproduce all the anatomical details, in order to later obtain a stone plaster model. Those obtained from an impression are generally based on dental plaster, which despite its improvements still retain some negative characteristics such as: low resistance to fracture by impact, low resistance to wear by abrasion, dimensional instability and radio opacity that prevents the simulation of endodontic procedures. In order to improve simulation in dental practice, the use of epoxy resin can be used to obtain models, this material is more resistant and has greater resistance to abrasion, it is radiolucent, which makes them Useful for replicating preparations and endodontic simulation procedures, the surface details obtained with epoxy resin are superior to those obtained with plaster. The use of simulators is an educational tool that favors the acquisition of certain abilities, skills, techniques and competencies necessary for the training of the student or professional in dentistry. In the present work, the technique for the elaboration of didactic dental models in epoxy resin to be used in the teaching of dental practice is described.(AU)

Evaluación de una resina epóxica experimental como material alternativo para obtención de modelos odontológicos / Evaluation of an experimental epoxy resin as an alternative material for dental casts

El objetivo de este estudio fue comparar la fidelidad de copia y estabilidad dimensional entre modelos de resina epóxica y modelos de yeso (Fuji Rock EP - GC Europe; Implant Stone - Polidental). Fue realizada la impresión de una matriz de acero para obtener 30 especímenes (n=10). La matriz simulaba dos piezas dentarias talladas para recibir coronas totales, sobre éstas fueron adaptados dos copings metálicos con aletas horizontales. Se evaluó al microscopio (Microscopio Measurescope, Nikon) la distancia entre el coping y la línea de terminación de las piezas talladas (en adelante, "desadaptación vertical") y la distancia entre las aletas horizontales de los copings (en adelante, "desadaptación horizontal"), las medidas obtenidas entre la matriz de acero y copings metálicos fueron consideradas como grupo control. Los copings metálicos fueron después adaptados sobre los modelos de yeso y sobre la resina experimental y fue realizada la evaluación al microscopio del mismo modo que el descrito anteriormente. Fueron realizadas 3 mediciones en dos tiempos (24 y 48 horas). Respecto a la desadaptación horizontal, el yeso FujiRock presentó una mejor estabilidad dimensional después de 24 horas, ya que la desadaptación fue similar estadísticamente a la desadaptación de la matriz (control) (p>0,05). Después de 48 horas, todos los grupos presentaron valores similares a la matriz (p>0,05). Respecto a la desadaptación vertical, todos los materiales presentaron diferencia estadísticamente significante en relación a la matriz (p?0,05), sin embargo, no hubo diferencia entre los materiales evaluados (p>0,05). La resina epóxica experimental puede ser una alternativa viable para la obtención de modelos odontológicos...

The aim of this study was to compare the accuracy of surface detail reproduction and dimensional stability of casts made from an experimental epoxy resin and gypsum (Fuji Rock EP - GC Europe; Implant Stone - Polidental). A steel matrix was molded to obtain 30 cast samples (n=10). The matrix simulated two teeth prepared to receive total crowns on which two metal copings with horizontal flaps were adapted. Three readings were performed (Measurescope microscope, Nikon) in order to measure the vertical and horizontal misfit and those readings were used as control. Metal copings were adapted over the gypsum and epoxy resin casts and three measurements were made in two periods (24 and 48 hours). Regarding the horizontal misfit, Fujirock had better dimensional stability after 24 hours, being statistically similar to the matrix (p> 0.05). After 48 hours, all groups had statistically similar values to the matrix (p> 0.05). Regarding the vertical misfit, all materials were statistically different in relation to the matrix (p ? 0.05). However, there was no statistically significant difference between the materials evaluated (p> 0.05). The experimental epoxy resin could be a suitable alternative to obtain dental casts...

Avaliação histopatológica do reparo apical e periapical em dentes de cães com vitalidade pulpar, após tratamento de canais radiculares utilizando dois cimentos obturadores à base de resina epóxica. Análise do pH e concentração de cálcio total / Histopathological evaluation of the apical and periapical repair of dog's teeth with vital pulp after biomechanic preparation and root canal fillings using resin-based sealers. Analysis of pH and calcium concentration

O objetivo do presente estudo foi o de avaliar comparativamente, dois cimentos obturadores de canal radicular à base de resina epóxica, AH Plus e Sealer Plus, através de duas diferentes metodologias. 1. Teste in vivo - Avaliação histopatológica em dentes de cães. Foram utilizados 36 canais radiculares de dentes pré-molares superiores e inferiores de 2 cães, com vitalidade pulpar, os quais, após o preparo biomecânico coadjuvado pela irrigação/aspiração e inundação com solução de hipoclorito de sódio a 1% (Líquido de Dakin), foram obturados pela técnica clássica complementada pela condensação lateral ativa, empregando os cimentos Sealer Plus (Grupo I) e AH Plus (Grupo II). Decorridos 90 dias após a obturação, os animais foram sacrificados por sobredose anestésica, as maxilas e mandíbulas removidas e fixadas em formol a 10%, durante 48 horas. Após processamento histológico de rotina, os cortes foram corados pela hematoxilina e eosina, pelo tricrômico de Mallory e Brown e Brenn. A análise histopatológica evidenciou que o cimento AH Plus, quanto à compatibilidade biológica, mostrou-se superior ao Sealer Plus, sendo o cimento que melhor permitiu a deposição de tecido mineralizado à nível apical, oferecendo um selamento quase completo na maioria dos casos, com infiltrado inflamatório ausente e quando presente era suave no tecido intersticial e/ou junto ao material obturador, assim como na região periapical. Já, com o cimento Sealer Plus, ocorreu predominantemente, selamento parcial, porém sempre acompanhado de infiltrado inflamatório de grau suave, no tecido intersticial, porém, mais concentrado, junto ao cimento obturador. Quando o material obturador era observado na região periapical, o infiltrado inflamatório apresentava-se, classificado como de grau moderado, concentrado próximo ao material e com reabsorção óssea alveolar. 2. Teste in vitro - Análise química. Com o objetivo de analisar o pH e liberação de cálcio total, por períodos que variaram de 0 a 5 dias, os cimentos endodônticos AH Plus e Sealer Plus, foram manipulados de acordo com as instruções dos fabricantes, e confeccionados os corpos -deprova, os quais foram pesados separadamente e colocados em água destilada, mantendo-se constante a relação massa/volume. Com relação ao pH, o cimento AH Plus ofereceu, após a reação de presa, um pH de 6,0, e logo em seguida, apresentou uma variação, tornando-se constante após 24 horas e com um pH alcalino de 7,5. Já o Sealer Plus, apresentou um pH crescente, até o 5o dia (pH =10,54). Com relação à liberação de cálcio total, os resultados obtidos mostram que o cimento Sealer Plus liberou uma grande quantidade de cálcio total, aos 5 dias (14,89 ppm), por ser mais solúvel que o AH Plus, que apresentou aos 5 dias, menor liberação de cálcio (0,144 ppm)

The scope of the present study was to evaluate comparativily, two root canal resin ­ based sealers - AH Plus and Sealer Plus through two different methodologies. 1. In vivo study ­ Histopathological evaluation in teeth of dogs. 36 root canals of lower and upper bicuspide teeth of 2 dogs with vital pulp, which after biomechanic preparation utilizing sodium hypochloride solution at 1% (Milton solution) were filling by classical technique complemented by active lateral condensation, using Sealer Plus (Group I) and AH Plus (Group II). 90 days after treatment, the animals were sacrificed by overdose anesthetical. After histopathological processing of routine, the sections were stained with hematoxiline and eosine, Mallory Trichromic and Brown and Brenn. The histopathological analysis had evidenced that the AH Plus sealer shows more biological compatibility in relation to the Sealer Plus being the sealer that shows more good deposition of mineralized tissue to the apical level, offering an almost full apical sealing in the majority of the cases, with infiltrated inflammatory absent and when present was mild in the interstitial tissue and/or together to the material sealer, as well as in the periapical region. With the Sealer Plus, partial apical sealing occurred, however always followed by infiltrated inflammatory of mild degree in the intersticial tissue, however, more concentrated, together to the filling material when in the periapical region, the inflammatory infiltrated was presented, classified as of moderate degree. 2. In vitro study - With the objective to analyze pH and clearing of total calcium by periods that had varied from 0 to the 5 days, the filling materials. AH Plus and Sealer Plus had been manipulated according to the manufacturers instructions. Samples of each sealer were prepared, which had been weighed separately and placed in distilled water, remaining at constant relation of mass/volume. In relation to the pH, the AH Plus sealer offered, after the reaction, one pH of 6.0, and soon after that, presented a variation, becoming constant after 24 hours and with pH alkaline of 7.5. Already the Sealer Plus, presented pH increasing, until 5 days (pH = 10.54). In relation to the clearing of total calcium, the results show that the Sealer Plus liberated a great amount of total calcium until 5 days (14.89 ppm), being more soluble than AH Plus, that offers until 5 days, minor calcium clearing (0.144 ppm)