Aesthetic Dentistry - What You Decided and What I Want: Shade Selection

ABSTRACT Objective: To assess the relationship between patients' and dentists' perceptions of shade selection and its impact on satisfaction with the prosthesis. Material and Methods: A single group pre-post study was conducted at the Prosthodontics department of a teaching hospital in India. One hundred ten participants were selected through a systematic random sampling technique with inclusion and exclusion criteria. Patients' attitudes regarding the aesthetics of their maxillary anterior teeth were recorded using a validated questionnaire. Shades for the intended prosthetic crown selected by the dentist and chosen by the patient were recorded separately, and patient satisfaction with the appearance of the final prosthesis was recorded. We used descriptive statistics followed by Pearson's Chi-square test and a binomial logistic regression model for inferential statistics. Results: 109 participant's data were available for final analysis. Patients choose lighter shades than the dentist's selection, which is statistically significant (p=0.000). 73.4% were satisfied with the final prosthesis, and the binomial logistic regression model identified using patient-selected shade for the final prosthesis was significantly associated with patients' satisfaction with the final prosthesis (OR=3.3, p=0.001). Conclusion: The patient's preference should be considered with the dentist's option when selecting a shade to create good esthetics.

Adaptación marginal e interna de cofias fabricadas por métodos convencionales, CAD/CAM de fresado y sinterizado por láser / Marginal and internal adaptation of copings manufactured by conventional methods, CAD/CAM milling and laser sintering

Introducción: la adaptación marginal e interna de nuestras restauraciones fabricadas por fundición sistemas de fresado y sinterización láser es uno de los factores clínicos más importantes para el éxito de las prótesis fijas, previniendo el riesgo de microfiltración y enfermedad periodontal. Objetivo: evaluar la adaptación marginal e interna de cofias metálicas en aleación Cr-Co confeccionadas por técnicas convencionales, CAD/ CAM de fresado y sinterizado por láser. Material y métodos: estudio de tipo experimental, comparativo e in vitro. Se imprimió un modelo maestro en Cr-Co, proveniente del escaneo de un premolar preparado para corona completa, sobre el cual se diseñaron 30 cofias divididas en tres grupos: el primero que corresponde al grupo cofias fundidas fresadas en disco de cera A (A = 10), el segundo grupo cofias fresadas en disco de metal presinterizado B (B = 10) y el tercer grupo cofias impresas por sinterización láser C (C = 10). Se empleó la réplica de silicona, colocando silicona al interior de cada cofia, sobre el modelo maestro, simulando al cemento, mediante una máquina de ensayo universal se realizó una compresión de 50 N. Luego de retirar cada cofia se rellenaron con silicona pesada de adición, obteniendo una réplica de silicona. Se efectuaron dos cortes transversales en sentido vestíbulolingual y mesiodistal. Se observó el espesor de silicona VPS (vinil poliéter silicona) mediante un estereomicroscopio (Nikon SMZ745T), obteniendo valores en micrómetros. Para el análisis estadístico se utilizó el software SPSS 25 con el fin de realizar la prueba de normalidad y ANOVA de dos vías bajo un nivel de confianza del 95%. Resultados: el menor gap lo obtuvo el grupo de fresadas, seguido de las impresas y por último las fundidas por métodos convencionales. ANOVA de dos vías reveló diferencias estadísticamente significativas entre los tres grupos (p < 0.0001). Conclusiones: se encontró que el gap varía con cada método de fabricación, la técnica convencional de fundido mostró un mayor gap, ninguna excediendo el rango clínicamente aceptable (AU)

Introduction: the marginal and internal adaptation of our restorations manufactured by casting, milling systems and laser sintering is one of the most important clinical factors for the success of fixed prostheses, preventing the risk of microleakage and periodontal disease. Objective: evaluate the marginal and internal adaptation of metal copings in Cr-Co alloy made by conventional techniques, CAD/CAM milling and laser sintering. Material and methods: an experimental, comparative and in vitro study, a Cr-Co master model was printed from the scan of a premolar prepared for a full crown. An experimental, comparative and in vitro study, a Cr-Co master model was printed from the scan of a premolar prepared for a full crown, on which 30 caps divided into three groups were designed; the first group corresponds to the cast copings milled on a wax disc A (A = 10), the second group milled copings on a presintered metal disc B (B = 10) and the third group printed by laser sintering copings C (C = 10). The silicone replica was used, placing silicone inside each coping, on the master model, simulating cement, using a universal testing machine, a 50 N compression was performed. After removing each coping, they were filled with heavy addition silicone, obtaining a silicone replica. Two cross-sections were made in the buccolingual and mesiodistal direction., observing the thickness of the VPS (vinyl polyeter silicone) silicone using a stereomicroscope (Nikon SMZ745T), obtaining values in micrometers. For the statistical analysis, the SPSS 25 software was used in order to perform the normality and two-way ANOVA tests under a 95% confidence level. Results: the smallest gap was obtained by the milled group, followed by the printed ones and finally those cast by conventional methods. Two-way ANOVA revealed statistically significant differences between the three groups (p < 0.0001). Conclusions: the gap was found to vary with each fabrication method, the conventional casting technique showed a larger gap, none exceeding the clinically acceptable range (AU)

Técnicas para prática de escultura dental / Techniques for the practice of dental sculpture / Técnicas para la práctica de la escultura dental

Objetivo: Caracterizar e diferenciar as técnicas de escultura dental, bem como descrever as etapas da ceroplastia de dentes. Revisão Bibliográfica: As principais técnicas encontradas foram: Técnica de escultura regressiva de dentes isolados em cera; técnica progressiva; técnica de ceroplastia em dentes articulados no manequim; enceramento progressivo em molde de gesso; enceramento progressivo com a oclusão dente-a-dente, cúspide-fossa; técnica de escultura de dentes articulados (restaurações unitárias); técnica de escultura de dentes articulados (restaurações múltiplas). No geral, o material e instrumental utilizados nas práticas de escultura são definidos pelo corpo docente do componente curricular Escultura Dental, e alguns desses diferem de uma universidade para outra, assim como o passo a passo seguido. Para o alcance da completa e correta escultura, faz-se necessário seguir a sequência evitando ultrapassar uma etapa sem antes haver cumprido com plena observância dos detalhes o passo imediatamente anterior. Considerações finais: Não houve uma técnica de escultura dental padrão a ser aplicada, entretanto acredita-se que a técnica de ceroplastia em dentes articulados no manequim destaca-se na prática laboratorial, pois os dentes a serem esculpidos precisaram respeitar o tamanho, a relação de oclusão, a relação interdental e o alinhamento, de forma a simular um procedimento clínico.

Objective: To characterize and differentiate dental carving techniques, as well as describe the stages of wax-up of teeth. Bibliographic Review: The main techniques found were: Technique of regressive sculpture of isolated teeth in wax; progressive technique; wax-up technique on articulated teeth on the dummy; progressive waxing in plaster mold; progressive waxing with tooth-to-tooth, cusp-fossa occlusion; articulated teeth sculpting technique (single restorations); articulated teeth sculpting technique (multiple restorations). In general, the material and instruments used in sculpting practices are defined by the faculty of the Dental Sculpture curricular component, and some of these differ from one university to another, as well as the step by step followed. In order to achieve a complete and correct sculpture, it is necessary to follow the sequence, avoiding going beyond a stage without first having completed the immediately preceding step in full observance of the details. Final considerations: There was no standard dental sculpting technique to be applied, however, it is believed that the wax-up technique on articulated teeth on the dummy stands out in laboratory practice, as the teeth to be sculpted needed to respect the size, the relationship of occlusion, interdental relationship and alignment, in order to simulate a clinical procedure.

Objetivo: Caracterizar y diferenciar las técnicas de tallado dental, así como describir las etapas del encerado de los dientes. Revisión Bibliográfica: Las principales técnicas encontradas fueron: Técnica de escultura regresiva de dientes aislados en cera; técnica progresiva; técnica de encerado en dientes articulados en el maniquí; encerado progresivo en molde de yeso; encerado progresivo con oclusión cúspide-fosa diente a diente; técnica de esculpido de dientes articulados (restauraciones individuales); Técnica de esculpido de dientes articulados (restauraciones múltiples). En general, los materiales e instrumentos utilizados en las prácticas de escultura son definidos por la facultad del componente curricular de Escultura Dental, y algunos de estos difieren de una universidad a otra, así como el paso a paso seguido. Para lograr una escultura completa y correcta, es necesario seguir la secuencia, evitando pasar de una etapa sin haber completado antes el paso inmediatamente anterior con total atención a los detalles. Consideraciones finales: No existía una técnica de esculpido dental estándar a aplicar, sin embargo, se cree que la técnica de encerado sobre dientes articulados sobre el maniquí se destaca en la práctica de laboratorio, ya que los dientes a esculpir debían respetar el tamaño, la relación de oclusión, relación interdental y alineación, con el fin de simular un procedimiento clínico. PALABRAS CLAVE: Corona del Diente; Escultura; Anatomía Artística.

THE POST TRANSFIXED IN THE CORONAL CAVITY INCREASES THE FRACTURE RESISTANCE OF WEAKENED AND DIRECTLY RESTORED TEETH? A SYSTEMATIC REVIEW

Introduction: The objective of this systematic review was to answer the question: Does the intraradicular post transfixed in the dental crown increases the fracture resistance of weakened and directly restored teeth? Methods: Electronic databases (MEDLINE/PubMed, LILACS, SCOPUS, EMBASE, Scientific Electronic Library Online - SCIELO, and Central Register of Controlled Trials - CENTRAL) were searched until March 2021, without language or year restriction. Grey literature was also searched through Google scholar and OpenGrey repository. Only in vitro stud-ies were included that evaluated the influence of the use of intraradicular post trans-fixed in the crown in the buccopalatal/lingual direction in the fracture resistance of the dental crown. Relevant results were summarized and evaluated. The risk of bias was also assessed in the studies. Results: Initial screening of databases resulted in 249 studies, of which 109 were excluded for being duplicates. Of 140 eligible pa-pers, fourteen studies met the inclusion criteria and were selected for full-text read-ing. Of these, two studies were excluded for not having access to the full article. All selected articles were classified as low risk of bias. Conclusion: Based on the studies, it is possible to conclude that the use of a transfixed post in the crown increases the fracture resistance of weakened and directly restored teeth.

Initial establishment of digital reference standardized crown models of the primary teeth / 北京大学学报(医学版)

OBJECTIVE@#To explore the construction process of the digital reference crown models, and to initially establish the digital reference crown models of the primary teeth to lay the foundation for the establishment of the standardized crown models and the future related applications of computer-aided design/computer-aided manufacture (CAD/CAM) technology to pediatric dentistry.@*METHODS@#This study randomly selected children who were caries free, aged from 4 to 5 years in several kindergartens of Haidian District of Beijing.Plaster dental models were made for the children after taking complete impressions.The digital dental models were reconstructed by using the three-dimensional (3D) dental model scanner.And then, Geomagic Studio, a 3D reverse engineering software, was employed to extract the single dental crown data, the mesiodistal and buccolingual diameters and the height of the crowns were measured.The object was reduced or enlarged by a numerical factor, and then the size of each dental crown was standardized.A total of 3-5 points features on the crown were created, and all the objects were aligned through the functions of feature-based alignment.Finally, through average-based object creation and smoothing, the digital models of reference crowns of the primary teeth were established.@*RESULTS@#A total of 40 plaster dental models from 16 boys and 26 girls were selected out for our further study.The digital dental models were reconstructed, and the mesiodistal and buccolingual diameters and the height of the crowns were measured by using reverse engineering technology.Comparing the results of using mesiodistal diameter, buccolingual diameter and height as the standards, we chose the mesiodistal diameters of crowns to do the standardization, and successfully established the digital reference models of 20 primary teeth crowns with detailed surface characteristics.@*CONCLUSION@#In this study, the digital reference crown models of the primary teeth were established by reverse engineering technology, providing reference value for the standardized crown models and application for clinical practice, scientific research and teaching.Furthermore, this study also contributes to the extensive application of CAD/CAM technology in pediatric dentistry and the development of CAD/CAM dental systems with independent intellectual property rights.

Incidence of Fracture in Single Ceramic Crowns in Patients with Chronic Tooth Wear: A Clinical Follow-up

ABSTRACT: The aim of this study was to identify the incidence of fractures in single crowns placed in individuals with chronic tooth wear. The sample selection was performed based on the evaluation of 218 patient records rehabilitated with single crowns placed by the same professional from a private clinic. After exclusion criteria, 43 individuals (18 males and 25 females) were included and a total of 112 single crowns distributed in both jaws. Three ceramic systems were evaluated: 34 feldspathic all-ceramic, 38 metal-ceramic with a core in gold electropositive alloy, and 40 In-Ceram Alumina. The intraoral photograph analysis adopted a diagnosis method of tooth wear according to the morphological variations of the teeth. Of the 112 crowns evaluated, 47 were placed in male and 65 in female patients, aged between 21 to 74 years (mean 27.5 years old). The variables gender (p = 0.83), presence of chronic tooth wear (p = 0.91), ceramic system (p = 0.24) and crown location (p = 0.86) did not present a statistically difference. However, the variables pulp vitality (p = 0.04) and survi val time (p = 0.01) presented a statistically significant difference. The evaluated ceramic systems can be considered as alternativ es of restorative material, even in individuals with clinical characteristics suggestive of chronic tooth wear.

RESUMEN: El objetivo de este estudio fue identificar la incidencia de fracturas en coronas individuales colocadas en individuos con desgaste dental crónico. La selección de la muestra se realizó en base a la evaluación de 218 registros de pacientes rehabilitados con coronas individuales colocadas entre 1999 y 2009 por el mismo profesional de una clínica privada. Después de analizar los criterios de exclusión, se incluyeron 43 individuos (18 hombres y 25 mujeres) y un total de 112 coronas individuales distribuidas en ambas mandíbulas. Este estudio evaluó coronas hechas de tres sistemas cerámicos: 34 de cerámica totalmente feldespática, 38 de cerámica de metal con un núcleo de aleación electropositiva de oro y 40 de alúmina enceram. El análisis de la fotografía intraoral adoptó un método de diagnóstico del desgaste dental de acuerdo con las variaciones morfológicas de los dientes. De las 112 coronas evaluadas, 47 se colocaron en hombres y 65 en mujeres, con edades comprendidas entre 21 y 74 años (media de 27,5 años). Con respecto a las coronas individuales, las variables género (p = 0,83), presencia de desgaste dental crónico (p = 0,91), sistema cerámico (p = 0,24) y ubicación de la corona (p = 0,86) no presentaron una diferencia estadísticamente significativa. Sin embargo, las variables vitalidad pulpar (p = 0.04) y tiempo de supervivencia (p = 0.01) presentaron una diferencia estadísticamente significativa. Los sistemas cerámicos evaluados pueden considerarse como alternativas de material restaurador, incluso en individuos con características clínicas que sugieren desgaste dental crónico.

Fractura no complicada de corona en un paciente con síndrome de Down / Uncomplicated crown fracture in a Down syndrome patient

RESUMEN Introducción: los traumatismos dentales representan uno de los más serios problemas de salud bucal en niños y adolescentes. Son poco frecuentes en el primer año de vida y aumentan cuando el niño comienza a caminar y correr. Los pacientes con síndrome de Down presentan características psico-motoras y físicas que le confieren una mayor susceptibilidad para sufrir lesiones traumáticas en la cavidad bucal. Presentación del caso: paciente con síndrome de Down de 16 años de edad, masculino, que sufrió una fractura no complicada de corona, para lo cual recibió tratamiento estético y restaurador con técnica directa de restauración con composite por capas. Este proceder permitió conseguir un resultado estético con un acabado muy natural, recobrando el tamaño de la pieza dental sin que fuera necesario su tallado. Conclusiones: se consiguió realizar un tratamiento convencional exitoso a una fractura no complicada de corona en un paciente con síndrome de Down cuyo pronóstico es favorable, teniendo en cuenta que, en Estomatología como en cualquier otra rama de las ciencias médicas, es preciso valorar las particularidades de cada individuo y vincular otras especialidades como la Psicología y la Medicina en el tratamiento integral, para alcanzar una atención de calidad.

ABSTRACT Introduction: dental injuries represent one of the most serious oral health problems in children and adolescents. They are rare in the first year of life and increase when the child begins to walk and run. Patients with Down syndrome have psycho-motor and physical characteristics that make them more susceptible to traumatic injuries in the oral cavity. Case report: 16-year-old male patient with Down syndrome who suffered an uncomplicated crown fracture, he underwent to an esthetic and restorative treatment with a direct layered composite restoration technique. This procedure allowed the achievement of an aesthetic result with a very natural finish, recovering the size of the dental piece without the need to carve it. Conclusions: a successful conventional treatment of an uncomplicated crown fracture was achieved in a patient with Down syndrome having a favorable prognosis, taking into account that, in Dentistry specialty as in any other branch of medical sciences, it is necessary to assess the particularities of each individual and to link other specialties such as Psychology and Medicine in the comprehensive treatment of these patients, in order to reach quality care.

Esthetic proportions of maxillary anterior teeth of 120 Chinese adults / 北京大学学报(医学版)

OBJECTIVE@#To analyze the esthetic proportions of maxillary anterior teeth in term of the apparent widths proportion of the adjacent teeth and width/height ratio of the clinical crown in 120 Chinese adults.@*METHODS@#Maxillary gypsum casts were obtained from the dental laboratories of stomatological hospitals in North China, Southeast China, and Southwest China, according to the inclusion criteria and exclusion criteria. Standardized digital photographs of each cast were recorded. The apparent widths and actual widths and heights of the central incisors, lateral incisors and canines were determined by ImageJ software for the calculation of apparent widths proportion of the adjacent teeth and width/height ratio of the clinical crown. The ideal apparent widths proportion (Golden proportion and Preston proportion) and width/height ratio (0.80) were tested. The gender, arch side, and regional differences were investigated.@*RESULTS@#The apparent widths proportion of the lateral/central incisor was 0.724±0.047, of the canine/lateral incisor was 0.814±0.092. The width/height ratio of the central incisor was 0.848±0.072, of the lateral incisor was 0.834±0.094, of the canine was 0.883±0.098. The esthetic proportions were different from the predicted ideal ratio (P < 0.001). The apparent widths proportion of lateral/central incisor was significantly larger in the right side than that in the left side (0.730± 0.044 vs. 0.718±0.050), and was significantly smaller in North China than that in Southwest China (0.711±0.051 vs. 0.731±0.044). The width/height ratio of the central incisor was significantly larger in the female than that in the male (0.855±0.074 vs. 0.835±0.068), and in the right side than that in the left side (0.855±0.073 vs. 0.842±0.072). The width/height ratio of the lateral incisor was significantly larger in the female than that in the male (0.843±0.097 vs. 0.817±0.084).@*CONCLUSION@#The apparent widths proportion of adjacent teeth and the width/height ratio of the clinical crown in Chinese adults are different from the foreigner's. The esthetic proportion parameters have significant population specificity, and the measurements cannot be generalized as well as it should be applied with caution.

Clinical performance of rensin-bonded composite strip crowns in primary incisors / 北京大学学报(医学版)

OBJECTIVE@#To evaluate the clinical success of the treatment of maxillary anterior primary incisors caries with composite resin strip crowns.@*METHODS@#Children who presented with severe early childhood caries and were treated comprehensive caries under general anesthesia from January to December 2016 were enrolled in this study. Composite crowns using preformed celluloid crown (3M ESPE, USA) called as "strip crown technique" were applied to treat vital primary incisors with two or multiple surface cavities. Selective etchings of enamel, Universal Bond adhesive and 3M Z350 resin were used to make strip crowns. The patients returned at the end of 6, 12 and 18 months and received clinical and radiologic examinations. Dentists who did not attend the treatment evaluated the strip crowns clinically by modified United States Public Health Service (USPHS) criteria.@*RESULTS@#Four hundred eighteen restorations, placed in 127 children aged 1.17-5.75 years (average of 3.22), were evaluated. The overall retention rate was 97.8% at the end of 6 months, 93.6% at 12 months and 89.2% at 18 months. After 18 months, 28 restorations (6.7%) were totally lost and 4.1% were rated as having lost some resin material. Only four teeth (1.0%) had secondary caries at the end of 18 months and 1.4% teeth had pulpal pathology requiring root canal treatment. Composite crowns had good performance in contour and adjacent contact and improved aesthetics significantly. Twenty-nine teeth (6.9%) showed mild gingivitis and 93.1% showed healthy gingival. 11.2% of the teeth demonstrated color change because plaque accumulation and the polish could remove the stains. The complete loss of strip crowns was mainly related to eating bites.@*CONCLUSION@#Strip crowns performed well for restoring primary incisors with large or multisurface caries for periods of over 18 months. The strip crowns can be a durable and aesthetic restoration for vital carious primary incisors with adequate tooth structure after caries removal. Functional movement is an important cause of complete loss. Because of the high technical sensitivity and its requirement of the cooperation of children, strip crowns are more suitable for older and cooperative children as well as children receiving dental treatment under sedation or general anesthesia.

Metal-ceramic partial fixed dentures: a retrospective study / Estudo retrospectivo de próteses parciais fixas metalocerâmicas

ABSTRACT Objective Metal-ceramic prosthesis are the treatment of choice in oral rehabilitation because of their high survival rates. However, there are few reports in the scientific literature about factors that lead to fractures of metal-ceramic prostheses. The aim of this study was to evaluate whether prostheses units number, abutment type and number, type of the prostheses, prostheses position in the mouth, bruxism and occlusal plaque influence the incidence of fractures in fixed metal-ceramic prostheses. Methods For this study, 16 patients were selected, totaling 74 metal-ceramic prostheses installed between 2000-2010, with follow up of at least four years. Besides dental history, other information was collected, such as patients' gender and age, prostheses installation date, and the ceramic system used. In case of prostheses fracture, a questionnaire was applied to identify signs of bruxism. A clinical evaluation was done to evaluate the prostheses integrity and opposing dentition characteristics. Success, failure and survival rates were determined. Results The results showed that the success rate of metal-ceramic prostheses was 87.8% and the survival rate was 89.1%. In addition, the success rate was independent of patient age, prostheses installation time, number of prosthesis, number of prosthesis' units and abutments. The qualitative variables also did not show significant statistical results between success and failure rates. Conclusion It was concluded that metal-ceramic prostheses have high success and survival rates, what guarantees longevity and indication of this type of prostheses in daily practice.

RESUMO Objetivo As próteses metalocerâmicas apresentam altas taxas de sobrevivência e, por isso, são indicadas para diversos casos em reabilitação oral. Entretanto, na literatura científica, existem poucos relatos clínicos sobre os fatores que levam à fratura dessas restaurações. Diante do exposto, o presente estudo teve como objetivo avaliar se a quantidade de elementos que compõem a prótese, se a quantidade de elementos por retentor, se o tipo de prótese e tipo de pilar, bem como sua localização, e o bruxismo, influenciam ou não nas fraturas dessas restaurações indiretas. Métodos Para isso, selecionaram-se 74 próteses metalocerâmicas, instaladas entre 2000 e 2010 em 16 pacientes, com acompanhamento mínimo de quatro anos. Foram coletadas informações dos pacientes, como: gênero, idade, data da instalação das próteses e cerâmica utilizada. Durante a avaliação clínica, observou-se a integridade da prótese e, em caso de fratura, coletava-se informações sobre a história clínica. As características do dente antagonista também foram avaliadas. Além disso, aplicou-se um questionário, com o intuito de identificar a provável presença de bruxismo. Resultados Como resultado, tem-se que a taxa de sucesso das próteses metalocerâmicas foi de 87,8% e, a taxa de sobrevivência, foi de 89,1%. A taxa de sucesso não teve influência da idade, tempo de instalação, número de próteses na boca, número de elementos ou pilares. Conclusão Embora pouco frequente, a fratura da cerâmica de cobertura foi a complicação mais comum. As próteses metalocerâmicas possuem altas taxas de sobrevida e de sucesso, o que garante a longevidade e a indicação desse tipo de restauração.

Scanning electron microscopy assessment of the load-bearing capacity of cad/cam-fabricated molar crowns

Abstract Although fiber-reinforced composites are commonly used in dental practice, whether fiber-reinforced crowns and fixed partial dentures can be used as definitive prostheses remains to be determined. This study used scanning electron microscopy to evaluate the load-bearing capacity of non-reinforced and fiber-reinforced composite (FRC) molar crowns prepared by computer-aided design/computer-aided manufacturing (CAD/CAM). The crowns were fabricated from three empirical FRC blocks, one empirical composite block, and one commercial ceramic block. The FRC resin was prepared by mixing BaO silicate particles, E-glass fiber, and dimethacrylate resin. Specimens were divided into five groups (n = 10), differing in the amounts of filler, resin, and fiber. Crowns were statically loaded until fracture. One-way analysis of variance and Tukey's post hoc multiple comparison tests were used for statistical analyses. The groups showed significant differences in load-bearing capacity; empirical bidirectional FRC resin blocks had the highest capacity, while commercial ceramic blocks had the lowest capacity. Molar crowns formed from FRC resin blocks had higher load-bearing capacity compared to non-reinforced composite resin and ceramic blocks. These results show that fiber reinforcement increased the load-bearing capacity of molar crowns.

Corona de espiga en trauma dentario: presentación de un caso / Crown of spike in dental trauma: case report

RESUMEN Fundamento: la conservación de los tejidos dentarios es el objetivo primordial de la profesión odontológica. Las lesiones traumáticas es una amenaza a los dientes y sus tejidos de sostén. Objetivo: confeccionar una corona de espiga de acrílico por el método directo para sustituir la corona en el diente 21. Presentación del caso: paciente blanco, masculino, de 29 años de edad que acude a consulta de Prótesis del Policlínico Universitario Julio Antonio Mella de la provincia Camagüey, remitido de los Servicios Básicos de Estomatología para rehabilitar con prótesis dental la corona del diente 21 que perdió por trauma facial. Como tratamiento se determinó la elaboración de una corona de espiga acrílica por el método directo para sustituir la corona del diente. Conclusiones: con la instalación de la corona de espiga acrílica, el paciente pudo restablecer su estado estético y funcional que le permitió la incorporación a su vida laboral y social.

ABSTRACT Background: the conservation of the dental tissues is the primary objective of the odontology profession. The traumatic lesions are a serious threat to the teeth and its supporting tissues. Objective: to make a pin crown of acrylic material for the direct method to substitute the crown in the tooth 21 that he lost due to a trauma. Presentation of the case: a white patient, masculine, 29 year-old who came to the prosthesis consultation at the University Polyclinic Julio Antonio Mella of the province of Camagüey, he brought about a remission of Basic Services of Dentistry to rehabilitate with dental prosthesis the crown of the tooth 21 that he lost for facial trauma. As a treatment plan, it was decided to make a crown of acrylic pin using the direct method to substitute the crown of the tooth. Conclusions: with the installation of the acrylic pin crown, the patient can recover his aesthetic and functional state, which allowed him to go back to his labor and social life.

Restaurações Biológicas como Alternativa para Reabilitação de Dentes com Extensa Destruição Coronária / Biological Restoration as an Alternative to Rehabilitation of Extensively Compromised Teeth

Objetivo: Descrever reabilitações com coroas biológicas por meio de dois casos clínicos, um dente anterior e um posterior. Material e Método: O estudo apresenta dois casos clínicos em que reabilitações de dentes extensamente destruídos foram realizadas. Em um dos casos é apresentada a reabilitação do dente 14 e no seguinte uma reabilitação simultânea dos dentes 21 e 22. Em ambos os casos foram utilizados dentes humanos provenientes de um banco de dentes humanos (BDH). Para a seleção dos dentes, utilizou-se como parâmetros os diâmetros dos dentes a serem reabilitados, bem como as medidas do dente homólogo contralateral. Os dentes obtidos junto a BDH foram seccionados, a coroa biológica esvaziada e então reembasada com resina composta sobre um modelo de gesso obtido dos pacientes. Após o reembasamento e ajustes oclusais ainda no modelo de gesso, as coroas foram cimentadas com cimento resinoso. Resultados: Em ambos os casos clínicos, os pacientes foram reabilitados adequadamente, de forma rápida e com custo reduzido. Conclusão: Restaurações biológicas podem ser utilizadas para reabilitação de dentes permanentes anteriores e posteriores; além de estimular o correto descarte de futuros dentes extraídos, sendo esses destinados a bancos de dentes humanos.

Objective: To describe rehabilitations with biological crowns by two clinical cases, one anterior and one posterior. Methods: The study presents two clinical cases in which extensively damage teeth were rehabilitated. In one, the rehabilitation of tooth 14 is presented and, in the other, a simultaneous rehabilitation of teeth 21 and 22 was performed. In both cases, human teeth from a human tooth bank (HTB) were used. For teeth selection, the diameters of the teeth to be rehabilitated, as well as, the measurements of the contralateral homologous tooth were used as parameters. The teeth obtained with HTB were sectioned, the biological crown emptied and then relined with composite resin on cast obtained from the patients. After the reline and occlusal adjustments, the crowns were cemented with resin cement. Results: The patients were rehabilitated properly, quickly and with reduced cost. Conclusion: Biological restorations can be used for rehabilitation of anterior and posterior permanent teeth; besides to stimulate the correct discard of extracted teeth, being these destined to human teeth banks.

Análise odontológica de detalhes anatômicos incisais e oclusais, em especial "flor de lis", para identificação forense ­ relato de caso / Dental analysis of incisal and occlusal anatomic details, in particular "flor de lis", for forensic identification ­ case report

A identificação humana é feita pela análise das particularidades de cada indivíduo, inclusive odontológicas, a qual consiste em um método que necessita de documentação prévia ante mortem de qualquer natureza, mas que contenha características específicas e individuais sobre o periciando a ser identificado. O presente trabalho tem como objetivo relatar um caso de identificação cadavérica cujo componente principal foi a comparação de dois modelos ortodônticos fornecidos pela família, com as peculiaridades dos arcos dentais do cadáver, demonstrando inúmeras coincidências e nenhuma divergência excludente. Nesta comparação, foram evidenciados detalhes anatômicos das bordas incisais, em especial a "flor de Lis" no dente 12 e das faces oclusais que foram suficientes para a identificação do desaparecido.

Human identification is done by analyzing the particularities of each individual, including dental ones, which consists of a method that requires previous documentation ante mortem of any nature, but which contains specific and individual characteristics about the victim to be identified. This study aims to report a case of cadaver identification whose main component was the comparison of two orthodontic models provided by the family, with the peculiarities of the dental arches of the corpse, showing numerous coincidences and no exclusionary divergence. In this comparison, anatomical details of the incisal edges were evidenced, especially the "flor de Lis" on tooth 12 and the occlusal faces that were sufficient to identify the disappeared.

Reconstrucción estética de fractura no complicada de corona en un paciente con síndrome de Down. Presentación de un caso / Aesthetic reconstruction of non complicated crown fracture in a Down Syndrome patient. Case presentation

Las características psíquico-motoras y físicas presentes en los pacientes con síndrome de Down le confieren una mayor susceptibilidad para sufrir lesiones traumáticas en la cavidad bucal, que causan afectaciones desde el punto de vista funcional, estético y psíquico. La atención estomatológica a estos pacientes debe ser diferenciada, por cuanto requieren técnicas innovadoras, preparación, agilidad y destreza por parte del estomatólogo, quien además debe integrarse a la familia y relacionarse con ellos desde edades tempranas. Por tales razones se presenta el caso de un paciente de 14 años de edad con síndrome de Down y una fractura no complicada de corona, en el que el tratamiento estético y restaurador logró desarrollarse de manera convencional.

The physical and psycho-motor characteristics present in Down syndrome patients provides a higher possibility to suffer from traumatic lesions in the oral cavity which cause affections from the functional, aesthetic and psychic point of views. Dental care to these patients should be differentiated since they require innovative techniques, training, agility and ability on the dentist part. This professional, in addition, should integrate to the family and be in contact with them since early ages. For these reasons a 14 year old Down syndrome patient is presented and a non-complicated crown fracture in which aesthetic and rehabilitating treatment could be conventionally developed.

Long-term evaluation of crown and root discoloration induced by different endodontic sealers

Aim: To evaluate crown and root discoloration promoted by different endodontic sealers after root canal filling. Methods: Eighty bovine incisors were prepared and filled with: Endofill, Sealer 26, AH Plus, and MTA Fillapex. Color was recorded using a spectrophotometer before endodontic treatment (T0) and at 24 hours (T1), seven days (T2), 30 days (T3), and 90 days (T4) after treatment. Analyses were performed on the middle and cervical regions of the crown, and on the cervical third of the root, immediately below the cementoenamel junction. The color alterations (ΔE) were calculated using Commission International de I'Eclairage (CIE) L*a*b parameters, and data were analyzed by analysis of variance (ANOVA) and Tukey's test (p<0.05). Results: All sealers induced color alterations. Sealer 26 resulted in the smallest changes in color (E = 5.32). The other materials did not present statistical differences (AH Plus E = 6.98; MTA Fillapex E = 6.88; Endofill E = 6.41). Of the three regions analyzed, the largest discoloration was observed at the cervical third of the root (E=10.67). In terms of time, the largest ΔE values (E=7.72) were observed at T4. Color changes at T1 (E=5.88), T2 (E=6.10), and T3 (E=5.89) were statistically similar. Conclusions: All endodontic sealers promoted discoloration on the tooth crown and root

Three-dimensional data fusion method for tooth crown and root based on curvature continuity algorithm / 北京大学学报(医学版)

Objective:To explore a three-dimensional (3D) data fusion and integration method of optical scanning tooth crowns and cone beam CT (CBCT) reconstructing tooth roots for their natural transition in the 3D profile.Methods: One mild dental crowding case was chosen from orthodontics clinics with full denture.The CBCT data were acquired to reconstruct the dental model with tooth roots by Mimics 17.0 medical imaging software, and the optical impression was taken to obtain the dentition mo-del with high precision physiological contour of crowns by Smart Optics dental scanner.The two models were doing 3D registration based on their common part of the crowns'' shape in Geomagic Studio 2012 reverse engineering software.The model coordinate system was established by defining the occlusal plane.crown-gingiva boundary was extracted from optical scanning model manually, then crown-root boundary was generated by offsetting and projecting crown-gingiva boundary to the root model.After trimming the crown and root models, the 3D fusion model with physiological contour crown and nature root was formed by curvature continuity filling algorithm finally.In the study, 10 patients with dentition mild crowded from the oral clinics were followed up with this method to obtain 3D crown and root fusion models, and 10 high qualification doctors were invited to do subjective evaluation of these fusion models.Results: This study based on commercial software platform, preliminarily realized the 3D data fusion and integration method of optical scanning tooth crowns and CBCT tooth roots with a curvature continuous shape transition.The 10 patients'' 3D crown and root fusion models were constructed successfully by the method, and the average score of the doctors'' subjective evaluation for these 10 models was 8.6 points (0-10 points).which meant that all the fusion models could basically meet the need of the oral clinics, and also showed the method in our study was feasible and efficient in orthodontics study and clinics.Conclusion: The method of this study for 3D crown and root data fusion could obtain an integrate tooth or dental model more close to the nature shape.CBCT model calibration may probably improve the precision of the fusion model.The adaptation of this method for severe dentition crowding and micromaxillary deformity needs further research.

Cone-beam computed tomography for the assessment of root–crown ratios of the maxillary and mandibular incisors in a Korean population / 대한치과교정학회지

OBJECTIVE: This retrospective, cross-sectional study aimed to establish reference data for normal crown and root lengths and the root–crown ratios (R/C ratios) for the mature maxillary and mandibular incisors in a Korean population by using cone-beam computed tomography (CBCT). METHODS: We included 672 Korean patients (141 men and 531 women; mean age, 27.2 ± 7.7 years) who underwent CBCT examinations during various dental treatments. Crown and root lengths and the R/C ratios of the maxillary and mandibular incisors were measured using CBCT data, which were analyzed to detect significant differences between demographic factors as well as sagittal and vertical skeletal or occlusal relationships. RESULTS: Teeth of the same type in each half-arch were symmetrical. The mean R/C ratios varied from 1.1 to 1.2 for the maxillary incisors and from 1.3 to 1.4 for the mandibular incisors. Crown and root lengths were greater in men than in women, regardless of tooth type. Root lengths and R/C ratios for the mandibular incisors were significantly greater in patients with skeletal Class II malocclusion or an excessive overjet than in the other patients. The R/C ratios for the mandibular incisors were lower in patients with an open bite than in those with a normal or deep bite. Moreover, the R/C ratios for the mandibular incisors increased with age. CONCLUSIONS: The data obtained in our study can serve as reference values for crown and root lengths and the R/C ratios for the maxillary and mandibular incisors in the Korean population.

Post and core build-ups in crown and bridge abutments: Bio-mechanical advantages and disadvantages

Dentists often place post and core buildups on endodontically treated abutments for crown and bridge restorations. This article analyzes the bio-mechanical purposes, advantages and disadvantages of placing a core or a post and core in an endodontically treated tooth and reviews literature on post and core biomechanics. The author assesses the scientific rationale of the claim that the main purpose of a post is to retain a core, or the claim that posts weaken teeth. More likely, the main function of a post is to help prevent the abutment, on which a crown is cemented, from fracturing such that the abutment separates from the tooth root, at a fracture plane that is located approximately and theoretically at the level of the crown (or ferrule) margin. A post essentially improves the ferrule effect that is provided by the partial fixed denture prosthesis. This paper also explores the difference between bio-mechanical failures of crowns caused by lack of retention or excess taper, versus failures due to a sub-optimal ferrule effect in crown and bridge prostheses.

Post and core build-ups in crown and bridge abutments: Bio-mechanical advantages and disadvantages

Dentists often place post and core buildups on endodontically treated abutments for crown and bridge restorations. This article analyzes the bio-mechanical purposes, advantages and disadvantages of placing a core or a post and core in an endodontically treated tooth and reviews literature on post and core biomechanics. The author assesses the scientific rationale of the claim that the main purpose of a post is to retain a core, or the claim that posts weaken teeth. More likely, the main function of a post is to help prevent the abutment, on which a crown is cemented, from fracturing such that the abutment separates from the tooth root, at a fracture plane that is located approximately and theoretically at the level of the crown (or ferrule) margin. A post essentially improves the ferrule effect that is provided by the partial fixed denture prosthesis. This paper also explores the difference between bio-mechanical failures of crowns caused by lack of retention or excess taper, versus failures due to a sub-optimal ferrule effect in crown and bridge prostheses.