Do denture teeth dimensions match natural anterior teeth? / As dimensões dos dentes artificiais correspondem aos dentes anteriores naturais?

ABSTRACT Objective To compare dimensions of natural maxillary anterior teeth and several denture teeth molds and also address differences between genders. Methods A single examiner with a digital caliper measured dental casts of 41 males and 55 females in order to determine CIW (central incisor width), CIL (central incisor length) and WS (width of anterior teeth on a straight line). In addition, WC (width of anterior teeth on a curve) was measured with a flexible ruler. These parameters were also observed on three denture teeth mold charts: Premium Pala, Vivodent and Trilux. The comparison between genders was analyzed using Student's t-test (?=.05), while absolute frequencies within several ranges were used to compare natural and denture teeth. Results CIW, CIL, WS and WC obtained from males were significantly higher than those found for females (p<0.05). CIW of nearly half of natural and denture teeth were within 8.0-8.5 mm. Almost half of natural teeth presented CIL values within 10.6-11 mm, while the highest frequency of denture teeth was observed within 9.6-10 mm. The majority of natural and denture teeth presented WS values within 42 to 49 mm. Only one denture teeth chart described WC values, which were mainly observed within 44-51 mm, while the majority of WC values obtained from natural teeth ranged from 48 to 55 mm. Conclusion Some commercially available denture teeth present dimensions not observed in natural teeth. Teeth dimensions in function of gender differences must be considered when selecting denture teeth.

RESUMO Objetivo Comparar as dimensões dos dentes anteriores superiores naturais e de diversos dentes artificiais para próteses e também abordar as diferenças entre os gêneros. Métodos Um único examinador mediu com um paquímetro digital dentes naturais de 41 homens e 55 mulheres para determinar CIW (largura do incisivo central), CIL (comprimento do incisivo central) e WS (largura dos dentes anteriores superiores em linha reta). Adicionalmente, CC (largura dos dentes anteriores em uma curva) foi aferida com uma régua flexível. Esses parâmetros também foram observados em três cartas moldes de dentes artificiais para prótese: Premium Pala, Vivodent e Trilux. A comparação entre os sexos foi analisada pelo teste t de Student (?=0,05), enquanto frequências absolutas foram usadas para comparar medidas dos dentes naturais e artificiais. Resultados CIW, CIL, WS e WC obtidos de homens foram significativamente maiores do que aqueles encontrados para mulheres (p<0,05). CIW de quase metade de dentes naturais e artificiais estavam entre 8,0-8,5 mm. Quase metade dos dentes naturais apresentaram valores CIL entre 10,6-11 mm, enquanto a maior frequência de dentes artificiais foi observada entre 9,6-10 mm. A maioria dos dentes naturais e artificiais apresentaram valores WS entre 42-49 mm. Apenas uma carta molde de dentes artificiais descreveu os valores de WC, que foram observados principalmente entre 44-51 mm, enquanto a maioria dos valores de WC obtidos em dentes naturais variaram de 48 a 55 mm. Conclusão Alguns dentes artificiais para próteses disponíveis comercialmente apresentam dimensões não observadas nos dentes naturais. As dimensões dos dentes em função das diferenças de gênero devem ser consideradas na seleção dos dentes artificiais.

Avaliação de dentes monorradiculares artificiais utilizados para treinamento endodôntico / Evaluation of artificial monoradicular teeth used for endodontic training

Introdução: É desafio do ensino pré-clínico em Endodontia fornecer aos alunos dentes artificiais que reproduzam a morfologia dos dentes humanos. Objetivo: Comparar a morfologia interna e externa de dentes artificiais monorradiculares com dados da literatura sobre dentes humanos. Material e método: Os dentes artificiais foram doados pelos fabricantes: Fábrica de Sorrisos, empresa A, (n=20), e IM do Brasil Ltda., empresa B, (n=20). Foi realizada mensuração do comprimento total do dente e da raiz, da altura, das dimensões vestibulopalatina e mesiodistal da coroa, com paquímetro digital. A descrição morfológica das raízes, coroas e câmaras pulpares foi realizada. A localização topográfica do forame apical principal foi avaliada após exploração dos canais com instrumento endodôntico tipo K #15 até este atingir visualmente o ápice radicular. Os dados foram dispostos em uma planilha de cálculo e realizou-se a análise estatística [ANOVA e pós-teste de Tukey (α=5%)]. Resultado: A amostra de caninos superiores da empresa B apresentou todas as variáveis dentro dos padrões morfométricos descritos na literatura. Em relação às morfologias interna e externa, a amostra de incisivos laterais superiores da empresa A foi a única a apresentar todas as variáveis dentro dos padrões descritos na literatura. Em relação à localização topográfica foraminal, os dentes da empresa A, assim como o canino inferior da empresa B, apresentaram tendência à posição distalizada e centralizada, vindo ao encontro da literatura. Conclusão: Nenhum dente artificial estudado apresentou total similaridade morfológica e morfométrica com a literatura analisada, diferindo em pelo menos uma das variáveis, sendo indicada aos fabricantes uma revisão dos seus modelos.

Introduction: It is a challenge of pre-clinical teaching in Endodontics to provide students with artificial teeth that reproduce the internal and external morphology of human teeth. Objective: To compare the internal and external morphology of single-rooted artificial teeth with data from the literature on human teeth. Material and method: The artificial teeth were donated from two companies: Fábrica de Sorrisos, company A, (n=20) and IM do Brasil Ltda, company B (n=20). Measurement of total tooth length, root, height, buccal-palatal and mesio-distal crown dimensions with digital caliper was performed. The morphological description of the roots, crown and pulp chamber was performed, the last one only after access. The topographic location of the main apical foramen was evaluated after canal exploration with a K #15 endodontic instrument until it visually reached the root apex. The data were arranged in a spreadsheet and statistical analysis was performed (ANOVA, followed by the Tukey post-test (α=5%)). Result: Regarding the morphometric parameters, the upper canine sample from company B presented all variables within the standards described in the literature. Regarding internal and external morphology, the sample of upper lateral incisors from Company A was the only one to present all variables within the standards described in the literature. Regarding the foraminal topographic location, the teeth of Company A, as well as the lower canine of company B, showed a tendency to the distalized and centralized position, in line with the literature. Conclusion: none of the artificial teeth studied showed total morphological and morphometric similarity with the control, differing in at least one of the variables, and a review of their models is indicated to the manufacturers.

In Vitro Effect of Acidic Challenges on the Physical Properties of Dental Prosthesis Artificial Teeth

Abstract Objective: To evaluate the effect of immersion and acid challenge with cola drink on color change (ΔE), Vickers hardness (VHN) and surface roughness (Ra) of artificial acrylic resin teeth. Material and Methods: The artificial teeth were divided into 6 groups (n= 8): TC (Trilux/Control), BC (Biotone/Control), TAC (Trilux/Acid challenge), BAC (Biotone/Acid challenge), TI (Trilux/Immersion) and BI (Biotone/Immersion). The teeth were embedded in acrylic resin and the labial side was serially polished to provide appropriate flat surface. The samples of TC, BC, TI, BI groups were immersed in artificial saliva and cola drink (coke) for 7 days, respectively. The acid challenge was performed with immersion of samples in coke for 5 min, and subsequently immersion in artificial saliva for 2h. This cycle was repeated at 4 times/day, during 7 days. The tests of VHN, ΔE and Ra were analyzed before and after the challenge and immersion groups. Data was analyzed by ANOVA, Tukey and T test (α = 0.05). Results: There was no difference in Ra values between groups after treatments. However, there was a decrease in VHN for all groups. BI (19.2 ± 0.3) presented significantly lower hardness than BAC (19.5 ± 0.9) and BC (20.2 ± 0.5). Groups BI (2.18 ± 0.41) and TI (1.50 ± 0.43) had statistically higher ΔE compared to the other groups. Conclusion: The hardness of resin teeth decreased after acid challenges, but the roughness surface was not affected. The color was more affected by the times of exposure in cola beverage and remineralization in artificial saliva, which were associated to the material degradation (AU).

¿Esquema oclusal balanceado o no balanceado en dientes monoplanos?: Una revisión de la literatura / Occlusal scheme balanced or unbalanced in monoplanes teeth?: A literature review

La prótesis total, es un elemento artificial destinado a reemplazar todos los dientes perdidos por algún factor externo o interno; para lo cual es necesario tener en consideración los objetivos principales que son el devolver la función masticatoria, fonética y estética. En una prótesis total se pueden dar un esquema oclusal balanceado el cual permite tener una estabilidad oclusal, utilizando dientes anatómicos o poliplanos permitiendo así darle al paciente una mejor eficacia masticatoria, confort y estética. Mientras que en el esquema oclusal no balanceado se utilizan dientes no anatómicos o monoplanos pero con una eficacia masticatoria disminuida y estética reducida. Cabe resaltar que también se puede conseguir que las prótesis totales tengan un esquema oclusal balanceado con dientes monoplanos, haciendo una serie de artificios en la confección de éstas. El presente artículo de revisión busca dar a conocer la técnica en la confección de un esquema oclusal balanceado usando dientes monoplanos.

Complete denture is an artificial element designed to replace all lost teeth because of some external or internal factor; for which it is necessary to take into consideration the main objectives that are returning the masticatory, phonetic and aesthetic function. In a complete denture, a balanced occlusal scheme can be given, which allows to have an occlusal stability, using anatomical teeth allowing thus giving the patient a better masticatory, comfort and aesthetic efficiency. While in the unbalanced occlusal scheme non-anatomical teeth are used but with reduced masticatory efficacy and reduced aesthetics. It should be noted that you can also get on a complete denture a balanced occlusal scheme with non.anatomical teeth, making a series of artifices in the preparation of these. The present review article seeks to present the technique in the preparation of a balanced occlusal scheme using non.anatomical teeth.

Efeito do desafio ácido nas propriedades superficiais das camadas externa e interna de dentes acrílicos reforçados / Effect of acid challenge on the surface properties of external and internal layers of cross-linked acrylic teeth

Introdução: Os dentes acrílicos artificiais devem apresentar característica de resistência aos ácidos, a fim de assegurar a manutenção de suas propriedades, ao longo de sua vida útil. Entretanto, não há estudos disponíveis na literatura pertinente sobre as propriedades superficiais de dureza e rugosidade das diferentes camadas de resina acrílica que compõem os dentes artificiais submetidos a ensaios de erosão simulada. Objetivo: Avaliar a dureza e rugosidade superficiais das camadas externa e interna de dentes artificiais acrílicos reforçados submetidos a desafio ácido. Metodologia: Molares (SR Postaris e Trilux) seccionados transversalmente foram avaliados inicialmente quanto à dureza Vickers e rugosidade. Esses ensaios foram repetidos após metade das amostras de cada tipo de dente (n=10) ser imersa em água destilada (controle) e outra metade em vinagre durante 15 min/dia por 28 dias. Os resultados foram analisados por ANOVA 2-critérios e teste de Tukey (α=0,05). Resultado: A dureza inicial da camada externa dos dois diferentes tipos de dente não sofreu alteração significativa pelo desafio ácido (p>0,05) e a imersão em vinagre não causou efeito deletério à dureza inicial da camada interna dos dois tipos de dentes avaliados (p>0,05). Após 28 dias, a rugosidade inicial de ambos os tipos de dentes estudados, para as duas camadas, não foi alterada com água ou vinagre (p>0,05). Conclusão: Os dentes acrílicos reforçados foram resistentes ao desafio ácido uma vez que suas camadas interna e externa não apresentaram alteração significativa de dureza e rugosidade superficiais.

Introduction: Artificial acrylic teeth must be resistant to acids for ensure the maintenance of their properties throughout their useful life. However, there are no studies available in the literature about the surface properties of hardness and roughness of the different layers of acrylic resin that make up the artificial teeth submitted to simulated erosion tests. Objective: To evaluate the surface hardness and roughness of external and internal layers of artificial cross-linked acrylic teeth submitted to acid challenge. Methodology: First molars (SR Postaris and Trilux) transversely sectioned had its Vickers hardness and roughness initially evaluated. These tests were repeated after half of the tooth samples (n=10) be immersed into distilled water (control) and half in vinegar during 15 min/day for 28 days. Data were analyzed using 2-way ANOVA and Tukey's test (α=0.05). Result: The initial external layers hardness of both was not significantly altered by acid challenge (p> 0.05) and the immersion in vinegar caused no deleterious effect on the initial internal layers hardness of the two tested teeth (p>0.05). After 28 days, the initial roughness of both teeth evaluated for the two layers was not affected by water or vinegar (p>0.05). Conclusion: The reinforced acrylic teeth were resistant to acid challenge since its internal and external layers showed no significant change in hardness and surface roughness.

Evaluation of methods for stain removal in acrylic resin denture teeth: in vitro study / Avaliação de métodos de remoção de manchas em dentes de resina acrílica para prótese total: estudo in vitro

Introduction: The staining of artificial teeth can be related to the acrylic resin abrasion caused by brushing, resulting in higher deposition of dyes from the beverage, and consequently higher aesthetic damage. Objective: The aim of this in vitro study was to evaluate methods for removal of stains from acrylic denture teeth using spectrophotometric analysis. Material and method: Artificial teeth were divided into twelve groups (n=10) according to the type of treatment (re-polishing - Re or immersion in Corega Tabs - Sp), staining solutions, coffee (Cf) and Coca-Cola® (Cc) or water (W) and with/without toothbrushing (B). The Sp specimens were submitted to seven immersion cycles (5 min each). The Re specimens were polished with pumice stone followed by Spain white paste. Color differences (ΔE) were captured by a spectrophotometer: T0 (baseline), T1 (after brushing/immersion in solutions) and T2 (after Re or Sp). Result: Statistically significant color change between T1 and T2 (paired T-test; α =.05) was observed for the group CfSp (p=.032); and for the groups BWRe (p=.000), BCfRe (p=.049) and CcRe (p=.042). Higher color changes were observed for the specimens submitted to toothbrushing (ANOVA two way; p<.001). Conclusion: It could be concluded that the immersion in sodium perborate (Corega Tabs) can be used for removal of coffee stains from denture teeth, and re-polishing for removal of Coca-Cola® stains. Still, toothbrushing produced greater color changes on denture teeth, regardless of the immersion solution.

Introdução: O manchamento dos dentes artificiais pode estar relacionado à abrasão da resina acrílica provocada pela escovação, resultando na maior deposição de corantes provenientes de bebidas, e consequentemente maior prejuízo estético. Objetivo: O objetivo do presente estudo foi avaliar métodos de remoção de manchas extrínsecas por meio de analise com espectofotômetro. Material e método: Dentes artificiais foram divididos em 12 grupos (n=10), de acordo com o tipo de tratamento (repolimento – Re ou imersão em perborato de sódio, Corega Tabs – Sp), tipo de solução de manchamento, café (Cf) ou Coca-Cola® (Cc) ou água (W) e com/sem escovação (B). Os métodos de remoção de manchas propostos (Re e Sp) foram realizados de acordo com protocolos pré-estabelecidos. Os espécimes Sp foram submetidos a 7 ciclos de imersão (5 minutos cada). O repolimento foi realizado com pastas de pedra pomes e branco de espanha, utilizando escovas de cerdas macias e rodas de feltro. As leituras de estabilidade de cor (ΔE) foram realizadas por meio de um espectrofotômetro: T0 (baseline), T1 (após escovação/imersão em bebidas), e T2 (após Re ou Sp). Resultado: Alterações de cor entre T1 e T2 (teste T pareado; α=0,05) foram observadas para o grupo CfSp (p=.032); e para os grupos BWRe (p=.000), BCfRe (p=.049) e CcRe (p=.042). Os dentes artificiais submetidos à escovação mostraram maior alteração de cor (ANOVA 2 fatores; p<0,001). Conclusão: Conclui-se que a imersão em perborato de sódio (Corega Tabs) pode ser utilizada para remoção de manchas de café e o repolimento para remoção de manchas de Coca-Cola®. Ainda, a escovação produziu as maiores alterações de cor nos dentes artificiais, independentemente da solução de imersão.

Immediate fixed partial denture after tooth extraction in patients with systemic diseases: A clinical report

For patients with systemic diseases who face difficulties visiting dental clinics, wearing fixed partial denture in the anterior region on the same day of tooth extraction can reduce the total period of treatment and the number of visits, as well as post-treatment psychological effect on the patient.

Effect of polishing and brushing on removal of cigarette smoke stains from artificial teeth / Efecto del pulido y cepillado en la eliminación de manchas de humo de cigarrillo en dientes artificiales

Color alteration is still a disadvantage of acrylic resin teeth and this problem seems to be greater in smokers. The objective of this study was to evaluate the efficiency of polishing and brushing on removal of stains from artificial teeth submitted to cigarette smoke. Forty denture teeth of distinct shades (62 and 69) were selected. The teeth were divided into 4 groups (n= 10), according to the tooth shade and method of stain removal performed: Groups 1 and 2 were submitted to the smoke of 20 cigarettes, and after new color readouts, were submitted to polishing with pumice stone and Spanish white paste. Groups 3 and 4 were submitted to 4 cycles of 5 cigarettes interspersed with standardized manual brushing. The values of color stability (DE) were compared using 2-way ANOVA, Bonferroni test (p<0.05). For all the groups, color change occurred at clinically unacceptable levels (E>3.3). After exposure to 20 cigarettes, the greatest degree of color change occurred for teeth in shade 62. Polishing significantly reduced the color change for groups 1 and 2, however, without significant difference between them. For Groups 3 and 4 there was no difference between the teeth of shade 62 and 69. When the treatments for each tooth shade were compared alone, there was similarity between polishing and brushing irrespective of the shade of samples. Routine manual brushing and common clinical polishing methods were capable of removing a large portion of staining caused by cigarettes, and there was no difference between the methods.

La alteración del color sigue siendo una desventaja de los dientes de resina acrílica y este problema parece ser mayor en los fumadores. El objetivo de este estudio fue evaluar la eficacia de pulido y cepillado en la eliminación de manchas de los dientes artificiales presentados al humo del cigarrillo. Se seleccionaron cuarenta dientes de la dentadura de tonos diferentes (62 y 69). Los dientes fueron agrupados en 4 grupos (n= 10), de acuerdo con el color del diente y el método de eliminación de manchas realizado: Los grupos 1 y 2 fueron sometidos al humo de 20 cigarrillos, y después de nuevas lecturas de color, se pulieron con piedra pómez piedra y pasta blanca española. Los grupos 3 y 4 se sometieron a 4 ciclos de 5 cigarrillos intercalados con cepillado manual estandarizado. Los valores de estabilidad del color (Delta E) se compararon mediante las pruebas de ANOVA de dos vías y Bonferroni (p<0,05). Para todos los grupos, el cambio de color se produjo a niveles no aceptables clínicamente (DE>3,3). Después de la exposición a 20 cigarrillos, el mayor grado de cambio de color se produjo para los dientes de tono 62. El pulido redujo significativamente el cambio de color para los Grupos 1 y 2, sin diferencia significativa entre ellos. Para los Grupos 3 y 4 no hubo diferencia entre los dientes de tono 62 y 69. Cuando los tratamientos para cada color de diente se compararon individualmente, hubo similitud entre el pulido y el cepillado, independientemente del tono. El cepillado manual rutinario y los métodos comunes de pulido clínicos fueron capaces de eliminar una gran parte de manchas causadas por los cigarrillos, sin diferencia entre los métodos.

Clinical study on artificial tooth selections for complete denture in edentulous jaws patients / 中国基层医药

Objective To compare the clinical effect of artificial tooth selections in complete denture restoration of edentulous jaws patients.Methods 76 cases with complete denture restoration of edentulous patients were divided into three groups according to prevalence and artificial tooth selection of different candidates.The complete denture satisfaction was compared after treatment for 3 months.Results The artificial teeth of full denture patients,speech,mastication,appearance,retention and comfort and so on for Class Ⅰ and Class Ⅱ patients had no significant difference (all P ＞ 0.05).The artificial teeth of full denture,selection of long median synthesis resin dental patients in speech,mastication and retention of satisfaction than selected anatomic occlusal resin teeth in Class Ⅲ for a choice of two different had significant differences (t =2.014,2.217,2.314,all P ＜0.05),but the appearance and comfort had no significant differences (t =1.023,0.957,all P ＞ 0.05).Conclusion Everything into must be taken into account when complete denture restoration are carried out for edentulous jaws patients.

Observation on the effect of ceramic faced in the repair of anterior teeth beauty / 中国基层医药

Objective To study the clinical effect of ceramic cover anterior on teeth beauty.Methods 138 teeth in 34 patients with dental fluorosis were divided into two groups,the control group (69 teeth in 16 patients) was given traditional PFM cover repair,the treatment group (69 teeth in 18 patients) was given ceramic cover,they were followed up for three years.The teeth remaining rate and patient satisfaction were compared,the match color,edge fit,healthy gums,restoration integrity were compared according to the Ryge standard.Results Teeth remaining rate in treatment group was 95.7％,which was significantly higher than control group (P ＜ 0.05).The patient satisfaction was 94.4％ in treatment group and 87.5％ in the control group,the difference was significant (P ＜ 0.05).The match color,edge coloring,healthy gums and teeth sensitivity were not different between the two groups (P ＞ 0.05).The restoration integrity and marginal fit of treatment group was better than control group (P ＜ 0.05).Conclusion The clinical effect of ceramic faced in the anterior teeth beauty repair,especially in the repair of dental fluorosis is remarkable,and the remaining teeth rate higher,repair,dental restoration integrity and marginal fit is significantly better than that of resin repair,patient satisfaction is higher,the water area from non-beryl popularization and application.

Análise comparativa da percepção estética entre estudantes de odontologia e seus pacientes em relação à seleção de cor e forma de dentes artificiais / Comparative analysis of the aesthetic perception between dental students and their patients regarding of color and shape of artificial teeth

A presente pesquisa teve por objetivo analisar a percepção estética entre estudantes de odontologia e seus pacientes em relação à seleção da cor e forma de dentes artificiais e avaliar a aplicabilidade clínica da régua TTI - Trubyte Tooth Indicator (Dentsply, York, PA, Estados Unidos), a qual se propõe a determinar as proporções do incisivo central superior e a classificação das formas faciais. Participaram deste estudo 60 pacientes dentados, de 19 a 59 anos e 60 estudantes de odontologia, de 18 a 25 anos. Ambos responderam a um questionário sobre seleção de dentes, e nos pacientes foram realizadas fotos da face com a utilização da régua para análise das medidas e formas faciais, como também foi mensurada com paquímetro digital a altura e largura do incisivo central esquerdo superior. As medidas obtidas através da régua foram comparadas com as proporções reais dos dentes naturais dos pacientes. Os resultados mostraram uma preferência por dentes da forma ovóide, tanto pelos alunos (51,7 por cento), como pelo pacientes (46,7 por cento); em relação à cor, houve uma preferência pela cor 1A, tanto por pacientes (55 por cento) como pelos alunos (31,7 por cento). Houve concordância entre a escolha da forma do dente pelo aluno e a forma da face do paciente observada através da régua Trubyte Tooth Indicator. Não houve diferença estatística entre os dois métodos na comparação da largura dos dentes. Observou-se, pela amostra avaliada, que o instrumento Trubyte Tooth Indicator pode ser utilizado como um meio auxiliar na seleção da largura dos dentes artificiais.

The aim of this work was to analyze the aesthetics perception among dental students and their patients in relation to color and shape of prosthetic teeth, and the practice applicability of the Trubyte Tooth Indicator - TTI (Dentsply, York, PA, United States) guide, in correlation of measures and classification of patients' faces. Sixty patients dentate were 19 to 59 years old and 60 dental students were 18 to 25 years old participated in this study. Every one had answered a questionnaire on teeth selection, and only the pictures of the patients were made with the use of device for face measures analysis, as well the height and width of upper left incisor was measured with a digital caliper. The results showed that a preference for ovoid form teeth as by students (51.7 percent) as by patients (46.7 percent); with regards to color there was a preference for 1A color as by patients (55 percent) as by students (31.7 percent). There was concordance between choice of the tooth form by student and the patient face form observed through Trubyte Tooth Indicator guide. There were no differences between both methods comparing width of the teeth. For assessed sample, it was concluded that the Trubyte Tooth Indicator guide is able to be used as an auxiliary means in selecting width of artificial teeth.

The role of polymerization cycle and post-pressing time on tooth movement in complete dentures

This study analyzed the influence of polymerization cycle and post-pressing time on tooth movement in complete dentures. Forty maxillary complete dentures were fabricated and randomly assigned to 8 groups (n = 5); the polymerization cycle (conventional long cycle in water bath, fast cycle in boiling water, and by microwave energy) and the post-pressing time (immediate and 6 hours) were varied. Metal reference pins were placed on the incisal border of the central incisors (RI and LI), on the buccal cusp of the first premolars (RP and LP), and on the mesiobuccal cusp of the second molars (RM and LM). Two transverse and 2 anteroposterior distances were measured with a linear optical microscope (Olympus Optical Co., Tokyo, Japan) with an accuracy of .0005 mm, before and after processing the complete dentures. The data collected were submitted to analysis of variance (ANOVA) and the Tukey Test at a significance level of 5 percent. When Clássico, a conventional heat-polymerizable acrylic resin, was polymerized by microwave energy, tooth movement was statistically significant for 2 distances, with the highest value being observed for the 6-hour post-pressing time. Onda-Cryl microwave acrylic resin processed by microwave energy presented the lowest tooth movement for 2 distances, considering the 6-hour post-pressing time. QC-20 acrylic resin presented no statistically significant change considering both post-pressing times in each distance evaluated. Tooth movement showed an asymmetric behavior, so the mastering of the processing method is essential to the precise execution of all laboratory steps, irrespective of the polymerization cycle and post-pressing time used.

Abrasion wear resistance of different artificial teeth opposed to metal and composite antagonists

One of the most important properties of artificial teeth is the abrasion wear resistance, which is determinant in the maintenance of the rehabilitation's occlusal pattern. OBJECTIVES: This in vitro study aims to evaluate the abrasion wear resistance of 7 brands of artificial teeth opposed to two types of antagonists. MATERIAL AND METHODS: Seven groups were prepared with 12 specimens each (BIOLUX & BL, TRILUX & TR, BLUE DENT & BD, BIOCLER & BC, POSTARIS & PO, ORTHOSIT & OR, GNATHOSTAR & GN), opposed to metallic (M & nickel-chromium alloy), and to composite antagonists (C & Solidex indirect composite). A mechanical loading device was used (240 cycles/min, 4 Hz speed, 10 mm antagonist course). Initial and final contours of each specimen were registered with aid of a profile projector (20x magnification). The linear difference between the two profiles was measured and the registered values were subjected to ANOVA and Tukey's test. RESULTS: Regarding the antagonists, only OR (M = 10.45 ± 1.42 µm and C = 2.77 ± 0.69 µm) and BC (M = 6.70 ± 1.37 µm and C = 4.48 ± 0.80 µm) presented statistically significant differences (p < 0.05). Best results were obtained with PO (C = 2.33 ± 0.91 µm and M = 1.78 ± 0.42 µm), followed by BL (C = 3.70 ± 1.32 µm and M = 3.70 ± 0.61 µm), statistically similar for both antagonists (p>0.05). Greater result variance was obtained with OR, which presented the worse results opposed to Ni-Cr (10.45 ± 1.42 µm), and results similar to the best ones against composite (2.77 ± 0.69 µm). CONCLUSIONS: Within the limitations of this study, it may be concluded that the antagonist material is a factor of major importance to be considered in the choice of the artificial teeth to be used in the prosthesis.

Avaliação da angulação do sulco de trabalho de dentes artificiais em relação ao plano de orientação e ao eixo de rotação vertical de lateralidade da mandíbula no articulador / Evaluation of the relationship amongst the working groove angulation of artificial teeth and the orientation plane and the vertical rotation axis of mandibular lateral translation in the articulator

Introdução - Na reabilitação protética, a oclusão e os movimentos mandibulares estão intrinsecamente ligados. Um dos conceitos sempre abordados na busca deste ideal é a relação entre os sulcos e as cúspides dos dentes com os movimentos mandibulares, que deve permitir um deslizamento livre de interferências entre ambos. Assim, foi proposto avaliar o grau de coincidência da angulação do sulco de trabalho do primeiro molar inferior artificial, quando posicionado no arco, em relação à trajetória descrita pela cúspide mésio-palatina do primeiro molar superior em relação ao eixo de rotação vertical de lateralidade da mandíbula no articulador semi-ajustável. Material e Métodos - Utilizou-se uma metodologia, através de um programa de editoração gráfica, que permitiu avaliar as imagens digitais de montagens em cera de dentes artificiais em prótese totais inferiores e de seus respectivos planos de orientação. Localizou-se o sulco de trabalho do primeiro molar inferior (A), a trajetória da cúspide mésio-palatina do primeiro molar superior adotando-se o eixo de rotação vertical no centro das esferas condilares (B), e a perpendicular à tangente ao plano de orientação (C). Resultados e Conclusões - Assim, mediram-se os ângulos formados entre A-C e A-B. Os resultados mostraram que houve casos onde A coincidiu com C, nos demais casos a angulação apresentou, em média, valores baixos, demonstrando que os parâmetros adotados para a montagem dos dentes artificiais foram seguidos. Não foi observada a coincidência entre A e B, indicando que, durante a reprodução do movimento de lateralidade no articulador, ocorre interferência na excursão da cúspide mésio-palatina do primeiro molar superior.

Introduction - In prosthetic rehabilitation, occlusion and mandibular movements are closely linked. Harmony between these factors is essential for treatment success. Therefore, the present study proposes to evaluate the degree of coincidence of the working groove angulation from the artificial mandibular first molar, when positioned on the arch, with the trajectory traced by the mesio-palatal cuspid from the maxillary first molar during mandibular lateral translation determined by the vertical axis rotation in a semi-adjustable articulator. Material and Methods - To identify this trajectory, it was utilized a graphical editing program. It was possible to evaluate digital images from artificial teeth mounted on wax for mandibular complete dentures, and their respective orientation planes positioned on the articulator. Through these images, the author located the working groove from the mandibular first molar (A), the trajectory described by the mesio-palatal cuspid from the maxillary first molar considering the vertical axis rotation at the center of the condilar spheres (B), and the perpendicular to the tangent of orientation plane (C). Results and Conclusions - Thus, the angle between A-C and the angle between A-B were measured. The results showed some cases where A coincided with C. In the remaining cases, the angulation displayed low mean values, illustrating that the mounting of artificial teeth followed the parameters adopted for the orientation plane according to the proposed technique. The coincidence between A and B was not observed, indicating that, during the lateral translation movement in the articulator, there is interference in the trajectory of the maxillary first molar mesio-palatal cuspid.

Critical analysis of artificial teeth for endodontic teaching

The purpose of this study was to evaluate the use of artificial teeth for endodontic teaching. A questionnaire was prepared and submitted to 18 professors of Endodontics from different Brazilian universities to evaluate the following features of five cloudy resin artificial teeth: internal and external anatomy; coronal chambers regarding their size, shape and canal path; root canal regarding their size, shape and position; fulfillment of the pulp chamber and root canals by considering the texture, quantity, color, and ease of handling; resin hardness and visualization of the radiographic image. The results presented favorable opinions, in terms of internal and external anatomy, coronal pulp chambers and root canal and handling and radiographic imaging. The contents of the pulp space and hardness of the teeth were considered satisfactory. The average grade assigned to the artificial tooth quality was 8.4, in a 0-10 scale. In conclusion, the artificial teeth have potential to replace the natural teeth in endodontic teaching; however, improvements are still necessary to reach a better quality model.