The influence of the retention feature in artificial teeth on its attachment to the thermoplastic resin denture base / Influência da forma de retenção em dentes artificiais de resina acrílica na fixação na base de prótese termoplástica

Objective: Teeth play a crucial role in masticatory efficiency and esthetic harmony making rehabilitation of partially edentulous patients a challenge because of the limitations of conventional removable partial dentures. As a therapeutic alternative, thermoplastic polymers are used in current dental practice either for practical processing purposes or aesthetics. However, it is recognized that the bond between acrylic resin artificial teeth and thermoplastic polymers has no chemical interaction, and depends on retentive features added to the teeth. This study analyzed the efficacy of two retentive forms of features through compressive strength test and as a secondary outcome, fracture and displacement resistance test. Material and Methods: Three groups of samples each with 14 sets of acrylic teeth were compared when two retentive features, single hole and groove retention, and a control group with teeth without any specific form. The experimental unit consisted of six maxillary anterior teeth, positioned in a linear pattern into a polypropylene block, where each tooth was submitted to a static load until its removal, on a universal testing machine. Results: Those specimens with a groove retention presented larger resistance to displacement when compared to the other groups (p <0.05). This was emphasized by the fracture of the tooth tested, with part of the cervical portion remaining embed in the base, and not its displacement as with (or without) the retentive feature. Conclusion: In this study, the type of retention influenced significantly to a better retention considering teeth and thermoplastic polymer base. The data in this study indicates that a groove placed on the artificial tooth offers significantly better retention efficacy to the point where the displacement was only possible after its fracture (AU)

Objetivo: Os dentes são um fator essencial na eficiência mastigatória. A harmonia estética e a reabilitação dos indivíduos parcialmente dentados tornam-se um desafio, frente às limitações das próteses parciais removíveis convencionais. Como uma alternativa terapêutica, os polímeros termoplásticos são utilizados na odontologia contemporânea, tanto para o seu processamento prático como seu apelo estético. Entretanto, pouco se sabe a respeito da união entre a resina acrílica de dentes artificiais e resinas termoplásticas, assim como a influência dos mecanismos de retenção, uma vez que não há interação química entre eles. O objetivo deste estudo foi analisar duas formas de retenção de dentes de resina acrílica a bases de prótese de material termoplástico, por força compressiva e como desfecho secundário, teste de resistência a fratura e deslocamento dos dentes artificiais. Material e Métodos: O presente estudo analisou dois tipos diferentes de retenções: uma cavidade com único ponto e uma canaleta de mesial a distal; e como grupo controle, dentes colocados sem qualquer recurso específico. A unidade experimental consistiu de seis dentes superiores anteriores, posicionados em linha em um bloco de polipropileno. Em cada dente artificial foi aplicada força até a sua remoção, em uma máquina universal de ensaios. Resultados: Os resultados mostraram que a retenção com canaleta apresentou maior força de deslocamento, quando comparado com os outros grupos (p <0,05). Tal fato foi evidenciado pelo teste de fratura e deslocamento, no qual parte da porção cervical do dente artificial permaneceu unida à base, não ocorrendo o deslocamento com (ou sem) a retenção. Conclusão: Neste estudo, o tipo de retenção influenciou de forma significante a retenção de dentes artificiais de resina acrílica a bases de prótese termoplásticas. Os dados deste estudo indicam que a confecção da retenção em canaleta nos dentes artificiais oferece significante aumento na eficiência da retenção, ao ponto em que o deslocamento do dente ocorreu somente após sua fratura (AU).

A new approach to endodontic access in anterior teeth: a pilot study / Uma nova abordagem para acesso endodôntico em dentes anteriores: estudo piloto

Introduction: The coronal opening is essential, during endodontic treatment, for direct access to the root canals. Usually, in the anterior teeth, endodontic access is achieved on the palatal/lingual surface, more specifically in the cingulum region. However, the lack of observation for dental positioning can lead to some accidents and complications, such as buccal perforations, causing esthetic damage and compromising the treatment. Objective: To evaluate the applicability of a new approach for performing coronal opening in anterior teeth, regarding the wear caused on the tooth crown, and to evaluate the ease of performing the new technique to minimize the risk of perforation. Material and method: Ten students (n=10) from the Improvement in Endodontics program participated in the present study. Twenty artificial teeth were used, which were upper, central incisors. Each participant performed two coronal openings. First, with no guidance (Group A - Conventional Technique) and afterward, a new opening, but with guidance with the spherical diamond tip placed parallel to the long axis of the tooth (Group B - Modified Technique). Result: The results showed that 90% of the participants considered the Modified Technique as having lower risk of accidents, as well as being easier for locating the pulp chamber. There was a statistical difference both in the measurement of the total area of wear and in the width, while there was no statistical difference in the height. Conclusion: Preliminary data collected with the survey were satisfactory for the Modified Technique. Statistically, it showed a favorable difference in relation to the area of wear and the width. However, in height there was no statistical difference.

Introdução: A abertura coronária é fundamental durante o tratamento endodôntico para um acesso direto aos canais radiculares. Em geral, em dentes anteriores, o acesso endodôntico é realizado na face palatina/lingual, mais especificamente em região de cíngulo. Entretanto, a falta de observação do posicionamento dentário pode levar a alguns acidentes e complicações, como as perfurações por vestibular, ocasionando dano estético e comprometendo o tratamento. Objetivo: Avaliar a aplicabilidade de uma nova abordagem de realização da abertura coronária em dentes anteriores, quanto ao desgaste ocasionado na coroa dentária, e avaliar a facilidade de execução da nova técnica para minimizar os riscos de perfurações. Material e método: Dez alunos (n=10) do curso de Aperfeiçoamento em Endodontia participaram do estudo. Foram utilizados vinte dentes artificiais, sendo eles incisivos centrais superiores. Cada participante realizou duas aberturas coronárias. Primeiramente sem nenhuma orientação (Grupo A - Técnica Convencional) e após, uma nova abertura, porém com orientação, com a ponta diamantada esférica posicionada paralelamente ao longo eixo do dente (Grupo B - Técnica Modificada). Resultado: Os resultados demonstraram que 90% dos participantes consideraram a Técnica Modificada como a de menor risco de acidentes e, ainda, de mais fácil localização da câmara pulpar. Houve diferença estatística tanto para a medida da área total de desgaste quanto para a largura, enquanto na altura não houve diferença estatística. Conclusão: Os dados preliminares coletados pelo questionário se mostraram satisfatórios para a Técnica Modificada. Estatisticamente, apresentou diferença favorável em relação à área de desgaste e largura, já em altura não houve diferença estatística.

Effects of conventional and heated tobacco product smoking on discoloration of artificial denture teeth.

STATEMENT OF PROBLEM: Cigarette smoke can cause discoloration of artificial denture teeth. However, studies on the effects of heated tobacco product smoke on artificial denture teeth are lacking. PURPOSE: The purpose of this in vitro study was to evaluate the effects of conventional cigarette and heated tobacco product smoke on the color stability of artificial denture teeth. MATERIAL AND METHODS: Ninety maxillary central incisor denture teeth (Endura Anterior HC5 A3; Shofu) were randomly divided into 3 groups (n=30). Teeth in the control group were exposed to air; those in group CC were exposed to conventional cigarette (Marlboro Medium; Philip Morris) smoke, and those in group HT were exposed to heated tobacco product (IQOS 2.4 plus holder, Marlboro Heets Silver; Philip Morris) smoke. Before the experiment, the shade of the artificial denture teeth was evaluated in accordance with the Commission International de I'Eclairage (CIELab) color system by using a spectrophotometer (Shadepilot; DeguDent GmbH). The average CIELab value was estimated by scanning the entire labial surface of each specimen. To simulate smoking, standard conditions described by the Coresta Recommended Method N°22 were used-the puff duration was 2 seconds, with a 60-second interval between puffs. For each cigarette, 6 puffs and 6 intervals were simulated across 372 seconds. A total of 105 cigarettes were used based on a smoking simulation of 15 cigarettes each day for 7 days. The teeth in the control group were stored in fresh air in the smoke chamber for the same period as those in the experimental groups. After the experiment, L∗, a∗, and b∗ values were measured, and ΔE was calculated to evaluate the color change. All statistical analyses were performed with a statistical software program using a paired t test to determine discoloration after exposure to cigarette smoke. One-way ANOVA and the Tukey test were used to evaluate the significant differences between groups (α=.05). RESULTS: Lightness was significantly lower in the CC and HT groups (P<.001). All CIELab values showed statistically significant differences in the CC group. The greatest color change was observed in the CC group (ΔE=6.93 ±0.59), whereas the HT group showed a clinically imperceptible color change (ΔE=0.79 ±0.21). Discoloration was minimal in the CC group (ΔE=0.34 ±0.13). CONCLUSIONS: Conventional cigarette and heated tobacco product smoke can change the color of denture teeth. Heated tobacco product smoke causes less discoloration of denture teeth.

Effect of conventional and rolled cigarette smoke on the colour of artificial teeth and effectiveness of hygiene protocols in removing pigmentation - An in vitro study.

Context: Artificial teeth are widely used in oral rehabilitation. Despite the benefits, they are more susceptible to colour changes, causing aesthetic problems. Aims: To evaluate the effect of conventional cigarette and straw smoke on the colour of artificial teeth and the effectiveness of hygiene protocols in removing pigmentation. Material and Methods: Acrylic resin incisors were divided into two groups (n = 50): Exposed to conventional cigarette and straw smoke. Regarding the effectiveness of hygiene protocols, the teeth were divided into ten subgroups with predetermined immersion times. The colour was measured with a colorimeter. The CIE values L* a* b* were recorded before and after exposure to smoke and after hygiene protocols. Statistical analysis used T-test of independent samples and two-way ANOVA with Bonferroni post-test (α = 0.05). Results: Conventional (16.16 ± 1.65) and straw (16.29 ± 1.95) cigarettes provided clinically unacceptable ΔE values, with no significant difference between them (P = 0.719). Conventional cigarettes promoted less luminosity (ΔL = -12.68 ± 1.28) (P < 0.001) and straw greater tendency to yellow (Δb = 11.00 ± 1.46) (P < 0.001). The hygiene protocols influenced the ΔE, ΔL, and Δb of the samples, depending on the type of smoke (P < 0.05). Conclusions: The conventional and rolled cigarette smoke promote an unacceptable colour change in artificial teeth. Hygiene protocols with the use of brushing, in isolation or in association with chemical solutions are more effective in removing pigmentation caused by both types of cigarettes compared to only the chemical solution.

Avaliação qualitativa de dentes artificiais de resina acrílica após escovação simulada / Qualitative evaluation of artificial acrylic resin teeth after simulated brushing

Introdução: os dentes artificiais de resina acrílica são amplamente utilizados na confecção de próteses, por apresentarem propriedades físicas, mecânicas e biológicas, além de características de fácil manuseio. No entanto, devido sua característica de baixa resistência à abrasão, a escovação pode levar à perda de massa dos dentes artificiais e aumento da rugosidade. Objetivo: avaliar de forma qualitativa a rugosidade superficial e polimento de dentes artificiais das marcas Hereaus Premium; Trilux e Vita, após período de 1 ano de escovação, com fotografias em Lupa Estereoscópica. Metodologia: para a realização deste estudo, serão utilizados 10 dentes artificiais de cada marca comercial (Trilux, Vita e Hereaus Premium). Os dentes serão fixados com resina ortoftálica em tubo de PVC de 15 mm de espessura. Para o teste de abrasão, será usada uma máquina de escovação simulada com escovas de dentes de cerdas macias e solução de pasta de dente. As imagens serão obtidas com câmera digital acoplada a lupa estereoscópica. A rugosidade superficial e o polimento serão analisados antes da escovação simulada e após 12 meses de escovação através das imagens. Resultados: após o teste de abrasão foi observado a presença de um desgaste superficial e/ou ranhuras na superfície dos dentes artificiais em todos os grupos. Porém não houve um padrão similar entre os corpos de prova de um mesmo grupo. Conclusão: Pode-se concluir que a escovação provocou o aumento da rugosidade superficial e alteração no polimento em todos os dentes artificiais utilizados.

Introduction: acrylic resin artificial teeth are widely used in the manufacture of dentures, as they have physical, mechanical and biological properties, in addition to easy handling characteristics. However, due to its characteristic of low abrasion resistance, brushing can lead to loss of mass of artificial teeth and increase in roughness. Objective: qualitatively evaluate the surface roughness and polishing of artificial teeth of Hereaus Premium brands; Trilux and Vita, after a 1-year brushing period, with photographs using a Stereoscopic Magnifying Glass. Methodology: for this study, 10 artificial teeth of each commercial brand will be used (Trilux, Vita and Hereaus Premium). Teeth will be fixed with orthophthalic resin in a 15 mm thick PVC tube. For the abrasion test, a simulated brushing machine with soft bristle toothbrushes and toothpaste solution will be used. Images will be obtained with a digital camera coupled to a stereoscopic magnifying glass. Surface roughness and polishing will be analyzed before simulated brushing and after 12 months of brushing through the images. Results: after the abrasion test, the presence of surface wear and/ or grooves on the surface of the artificial teeth was observed in all groups. However, there was no similar pattern between the specimens of the same group. Conclusion: it can be concluded that brushing caused an increase in surface roughness and change in polishing in all artificial teeth used.

Morphometric evaluation of multirooted artificial teeth used for endodontic training / Avaliação morfométrica de dentes artificiais polirradiculares utilizados para treinamento endodôntico

Introduction Dental practice professionals encounter several urgency cases, mainly related to endodontic problems. To attend to these, professionals need extensive prior preclinical training, being one of the main difficulties the search for models that simulate dental morphology. Aim To compare the external morphometry of multirooted artificial teeth to literature. Material and method The artificial teeth (Upper First Premolar, Upper First Molar and Lower First Molar) were donated by the manufacturers: Fábrica de Sorrisos (FS) and IM do Brasil LTDA (IM), totaling 30 teeth. The total length of the tooth and root, height and buccal-palatal and mesial-distal dimensions of the crown were measured with a digital pachymeter. The data were placed in a spreadsheet and the statistical analysis was performed [ANOVA or Kruskal-Wallis and then, Dunnett's test (α=5%)]. Result The Upper Molar samples of the company Fábrica de Sorrisos presented all variables within the morphometric patterns described in the literature. The other dental groups presented statistically significant differences, maintaining or not a certain proportionality. Conclusion Of all the dental groups analyzed, the upper molar from the company Fábrica de Sorrisos was the only one that presented all the external morphometric aspects according to literature.

Introdução Dentro da prática odontológica, os profissionais podem receber diversos casos de urgência, principalmente relacionados a problemas endodônticos e, para atendê-los, há a necessidade de um extenso treinamento pré-clínico prévio, sendo uma das principais dificuldades a busca por modelos que simulem a morfologia dentária. Objetivo Comparar a morfometria de dentes artificiais polirradiculares à literatura. Material e método Os dentes artificiais (Primeiro Pré-molar Superior, Primeiro Molar Superior e Primeiro Molar Inferior) foram doados pelos fabricantes: Fábrica de Sorrisos (FS) e IM do Brasil Ltda. (IM), totalizando 30 dentes. Foi realizada mensuração do comprimento total do dente e o da raiz, da altura e das dimensões vestíbulo-palatina e mésio-distal da coroa, com paquímetro digital. Os dados foram dispostos em uma planilha de cálculo e realizou-se a análise estatística [ANOVA ou Kruskal-Wallis e, após, teste de Dunnett (α=5%)]. Resultado A amostra de molares superiores da empresa FS apresentou todas as variáveis dentro dos padrões morfométricos descritos na literatura. Os demais grupos dentários apresentaram diferenças estatisticamente significantes, mantendo ou não certa proporcionalidade. Conclusão De todos os grupos dentários pesquisados o molar superior da empresa FS foi o único que apresentou todos os aspectos morfométricos externos de acordo com os dados da literatura.

[A Case of a Bronchial Foreign Body (Artificial Tooth) in the Right Middle Bronchus Without Respiratory Symptoms].

Patients with bronchial foreign bodies often present with subjective symptoms, mainly cough, and removing the foreign bodies is difficult. Bronchial foreign bodies are mostly located in the right lower bronchus, and rarely in the right middle bronchus. An 85-year-old man had no subjective symptoms. He aspirated an artificial tooth during dental treatment the day before visiting our clinic, and consulted his home doctor. He was admitted to our hospital because a chest radiograph indicated the presence of a foreign body in the right middle and lower lung field. Chest computed tomography showed that the bronchial foreign body was located in the right middle bronchus, and it was accompanied by an artifact in the circumference of the lesion, and it seemed to be the metal piece of an artificial tooth. Three-dimensional CT showed the root of the artificial tooth located in center side of the right middle bronchus, and, considering the invasiveness, we decided to remove the tooth by flexible bronchoscopy. The bronchoscopy revealed a metal piece occluding the right middle bronchus without granulation, and we could remove the tooth immediately by grasping the root of the tooth with alligator forceps. We experienced a case of a foreign body located in the right middle bronchus without respiratory symptoms. It is important to carry out image examinations, because elderly patients may not exhibit respiratory symptoms.

Single anterior tooth replacement with direct fiber-reinforced composite bridges: A report of three cases.

In today's dentistry, with the development of adhesive techniques and the improvement of resin-based materials, invasive restorative treatments have been replaced by minimally invasive or noninvasive restorative procedures. Fiber-reinforced adhesive bridges are minimal-invasive or noninvasive restorations that can be applied for definitive restoration in single tooth loss or short spans, where teeth or implant-supported fixed partial prosthesis cannot be applied. This case series describes the rehabilitation of three patients with anterior single tooth loss using the direct fiber-reinforced adhesive bridge. In all patients, esthetic and functional deficiencies in the missing tooth regions were solved with this minimally invasive technique, which is both cost-effective and conservative of tooth structures. During the three-year follow-up of these cases, there was neither fracture nor decementation in the restorations. Also, no caries or sensitivity was noted in the support teeth.

Effect of radiotherapy on the artificial acrylic resin tooth bond to the acrylic resin denture base.

This study aimed to evaluate the fracture resistance of the bond between an artificial acrylic resin tooth and its acrylic resin denture base after radiotherapy with maximum therapeutic doses of 40 and 70 Gy. Sixty wax blocks were fabricated with heights of 4.0 cm and bases with dimensions of 1.0 cm2 and 1.8 cm2. A posterior acrylic resin tooth was placed on each wax block on the base with the smallest area. Thirty of the blocks were thermopolymerized using the conventional technique and 30 using the microwave technique, and the blocks were divided into 6 groups (n = 10): 1 (control, conventional) and 2 (control, microwave) did not receive radiation; 3 (conventional) and 4 (microwave) received a total dose of 40-Gy radiation; and 5 (conventional) and 6 (microwave) received a total dose of 70 Gy. The groups of 40 and 70 Gy received fractional doses of 2 Gy per day, 5 days per week, until their respective total dose was completed. During the study, all specimens were stored in ballistic gel at a temperature of 37ºC. After the radiotherapy treatments, the bonds between teeth and bases in all groups were submitted to a fracture resistance test. Analysis of variance and Tukey test (P < 0.05) verified no statistically significant differences between groups 1 and 3 (P = 0.727), 2 and 4 (P = 0.537), or 4 and 6 (P = 0.727). However, there were statistically significant differences between groups 3 and 5 (P < 0.001), 5 and 1 (P = 0.006), and 6 and 2 (P = 0.034). Therefore, for both polymerization techniques, the maximum radiation dose of 70 Gy weakened the bond between the acrylic resin tooth and its acrylic resin base.

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).

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.

Color Stability of Acrylic Resin Teeth After Immersion in Staining Solutions / Análisis del Cambio de Color de Dientes Artificiales Tras Inmersión en Soluciones Colorantes

ABSTRACT: The objective of this study was to evaluate the color alteration of four brands of artificial teeth (Art Plus, Trilux, Bionote and Biolux), after immersion in color solutions of coffee, red wine and urucum. We used 80 artificial teeth, which were standardized with 2 mm thickness. Then, they were subjected to finishing and polishing, and divided into 4 groups (n = 05), which were immersed in one of the 3 types of dye, plus distilled water (control). The samples were immersed daily for 4 hours, then they were removed, washed in tap water, dried with absorbent paper and immersed in distilled water for the subsequent hours in a biological glasshouse at 37 ºC, for 21 days. The evaluation of the color change was made in the periods of 0, 7, 14 and 21 days, by means of the tristimulus colorimeter. The data were subjected to the ANOVA and Tukey test with a 5 % significance. The results showed that the urucum was the substance that caused the greatest staining while the coffee and the wine did not show statistical difference. Regarding trademarks, Trilux presented a statistical difference compared to the other commercial brands, revealing colorimetric alteration only in the 14-day period. It was concluded that the composition of the artificial teeth, the type of pigmenting agent and the immersion time determine the color change.

RESUMEN: El objetivo de este estudio fue evaluar la alteración de color de cuatro marcas de dientes artificiales (Art Plus, Trilux, Bionote y Biolux), después de inmersión en soluciones colorantes de café, vino tinto y urucum. Se utilizaron 80 dientes artificiales, los cuales fueron estandarizados con 2 mm de espesor. En seguida, los mismos fueron sometidos al acabado y pulido, y divididos en 4 grupos (n = 5), los cuales fueron inmersos en uno de los 3 tipos de colorante, más agua destilada (control). Las muestras permanecieron inmersas diariamente durante 4 horas, luego fueron retiradas, lavadas en agua corriente, secas con papel absorbente e inmersas en agua destilada por las horas subsiguientes en invernadero biológico a 37 ºC, por 21 días. La evaluación del cambio de color se realizó en los períodos de 0, 7, 14 y 21 días, por medio del colorímetro tristimulo. Los datos fueron sometidos a la prueba ANOVA y Tukey con un 5 % de significancia. Los resultados demostraron que el urucum fue la sustancia que provocó mayor manchado mientras que el café y el vino no presentaron diferencia estadística. En cuanto a las marcas comerciales, el Trilux presentó una diferencia estadística en comparación con las otras marcas comerciales, revelando alteración colorimétrica sólo en el período de 14 días. Se concluyó que la composición de los dientes artificiales, el tipo de agente pigmentante y el tiempo de inmersión determinan el cambio de color.

Radiopacidade de dentes artificiais para treinamento pré-clínico de endodontia / Artificial tooth radiopacity for preclinical endodontic training

Resumo Introdução Dentes artificiais têm sido utilizados para a prática odontológica e, segundo seus fabricantes, apresentam muita similaridade aos dentes humanos para treinamento. Objetivo Avaliar a radiopacidade de dentes endodônticos artificiais para uso em atividades de ensino e saber a percepção de docentes quanto à análise radiográfica. Material e método Trinta réplicas de incisivos centrais superiores de três marcas comerciais (Fábrica de Sorrisos, IM do Brasil e Real Dent) e um incisivo humano foram utilizados. Foram dispostos sobre um sensor radiográfico o dente humano e um dente artificial de cada empresa. As análises de radiopacidade foram feitas no programa Photoshop® em triplicata em quatro regiões distintas: porção central da coroa e nos terços cervical, médio e apical do canal. A percepção quanto à utilização dos dentes como instrumento prático de ensino foi avaliada por meio de um questionário aplicado a oito professores de endodontia. Para análise estatística dos valores de radiopacidade, foi utilizada a ANOVA, seguida do teste de Tukey. Foi empregado um nível de significância de 5%. Para análise do questionário, foram empregados métodos descritivos e por porcentagem de dados no que se refere à frequência das respostas. Resultado Houve diferença de radiopacidade entre os diferentes dentes testados em cada região analisada (p > 0,05). Na percepção dos professores com relação à utilização dos dentes no ensino, eles colocaram em ordem crescente os seguintes dentes para uso: IM do Brasil, Fábrica de Sorrisos, Real Dent e humano. Conclusão A radiopacidade dos dentes artificiais foi diferente do humano. O dente artificial da Fábrica de Sorrisos apresentou os maiores valores de radiopacidade. Contudo, os professores consideraram ideais para utilização no ensino apenas o dente humano e o dente da Real Dent.

Abstract Introduction Artificial teeth have been used for dental practice which, acoording to their manufactures, bear much similarity to human teeth for training. Objective To evaluate radiopacity of artificial endodontic teeth for use in teaching activities and to know the perception of teachers regarding radiographic analysis. Material and method Thirty replicates of upper central incisors of three trade marks (Fábrica de Sorrisos, IM do Brasil and Real Dent) and a human incisor were used. On a radiographic sensor, human tooth and one artificial tooth of each marks were arranged. Radiopacity analyzes were performed using Photoshop® in triplicate in four distinct regions: central portion of the crown and in the cervical, middle and apical thirds of the canal. The perception about the use of teeth as a practical teaching instrument was evaluated through a questionnaire applied to eight teachers of Endodontics. For statistical analysis of the radiopacity values ​​ANOVA was used, followed by the Tukey test. Significance level of 5%. For the analysis of the questionnaire were used descriptive methods and percentage of data regarding the frequency of responses. Result There was a difference in radiopacity between the different teeth tested, in each region analyzed (P > 0.05). In the teachers' perception regarding the use of teeth in teaching, the teachers placed the following teeth for use: IM do Brasil, Fábrica de Sorrisos, Real Dent and human. Conclusion The radiopacity of the artificial teeth was different from the human teeth. The artificial tooth of the Fábrica de Sorrisos presented the highest values ​​of radiopacity. The teachers considered ideal for use in teaching only the human teeth and the prototype Real Dent.

Efeito de diferentes soluções irrigadoras na microdureza superficial Knoop de dentes artificiais / Effect of different irrigation solutions on the Knoop surface microhardness of artificial teeth

Resumo Introdução Dentes artificiais têm sido empregados para a prática de ensino pré-clínico. Porém, não se sabe o comportamento dos mesmos frente aos diferentes procedimentos realizados durante um tratamento endodôntico simulado. Objetivo Avaliar a microdureza de réplicas de dentes humanos, frente a diferentes soluções irrigadoras. Material e método Quarenta e cinco incisivos centrais superiores artificiais de três marcas comerciais nacionais (dentes "A", "B" e "C") e 15 incisivos humanos foram utilizados. As amostras foram seccionadas a 5 mm do ápice dentário. Os fragmentos radiculares foram fixados em resina para posterior teste de microdureza. Os ensaios da microdureza Knoop foram realizados em dois momentos: momento 1 - microdureza inicial; momento 2 - microdureza final, que foi feita após o uso das soluções irrigadoras (Cloreto de Sódio a 0,9%, Hipoclorito de Sódio a 2,5% e Gluconato de Clorexidina a 2%). As endentações deixadas na superfície da amostra foram mensuradas. O valor obtido para microdureza de cada amostra foi feita com base na média de três endentações. Para análise estatística, foram utilizados os testes ANOVA e Teste t pareado, com nível de significância de 5%. Resultado Os dentes artificiais "A" e "C" apresentaram valores inferiores de microdureza quando comparados ao dente humano (P = 0,05). Não houve diferença estatística entre os dentes artificiais "B" e o dente humano (P = 0,2428). Quanto ao uso das diferentes soluções irrigadoras, também não houve diferença na microdureza das peças dentárias. Conclusão Embora a solução irrigadora não tenha influenciado a microdureza, os dentes artificiais apresentaram valores de dureza inferiores aos do dente humano.

Abstract Introduction Artificial teeth have been used for preclinical teaching practice. However, the behavior of the same is not known in relation to the different procedures performed during a simulated endodontic treatment. Objective To evaluate the microhardness of replicates of human teeth, in front of different irrigating solutions. Material and method Forty-five artificial upper central incisors of three national trade marks (teeth "A", "B" and "C") and fifteen human incisors were used. Samples were sectioned 5 mm from the apex. The root fragments were fixed in resin for later microhardness test. The Knoop microhardness tests were performed in two moments: moment 1 - initial microhardness; moment 2 - final microhardness, which was done after the use of the irrigating solutions (0.9% sodium chloride, 2.5% sodium hypochlorite and 2% chlorhexidine gluconate). The indentations left on the sample surface were measured. The obtained value for microhardness of each sample was made based on the average of three indentations. ANOVA and Paired t-test were used for statistical analysis. Significance level of 5%. Result Artificial teeth "A" and "C" presented lower values ​​of microhardness when compared to human teeth (P = 0.05). There was no statistical difference between the artificial teeth "B" for the human (P = 0.2428). Regarding the use of different irrigation solutions, there was also no difference in the microhardness of dental pieces. Conclusion Although the irrigating solution did not influence the microhardness, the artificial teeth presented values ​​of hardness inferior to the human tooth.

Comparative analysis of stress distribution in different prosthetic solutions for Kennedy class I bilateral posterior edentulous arches / Análise comparativa da distribuição de tensão em diferentes soluções protéticas para desdentado posterior bilateral "classe I de Kennedy"

One of greatest challenges of dentists is the rehabilitation of free-end Kennedy class I and class II patients due to the improper occurrence of stress around the supporting structures of conventional removable dentures during mastication. This work aimed to compare the stress distribution in different prosthetic solutions. For this analysis, four photoelastic models (PM) were produced simulating a Kennedy class I arch with the remaining teeth 34 through 44. In all models, teeth 33, 34, 43, and 44 received metal crowns. In addition to the crowns, the A model (PMA) received a conventional removable partial denture (RPD), the B model (PMB) received a RPD associated with a semi-rigid attachment, the C model (PMC) received a RPD associated with a rigid attachment, and the D model (PMD) received a RPD associated with implant and rigid attachment. Evenly distributed loads were applied on the last artificial tooth of the prostheses. Based on the results of the distributed load, the conventional prosthesis presented the best results for all regions (averages ranging from 25.70 to 17.80), followed by the prosthesis associated with the implant, the prosthesis associated with the rigid attachment, and lastly, the prosthesis associated with the semi-rigid attachment. The same result can be observed in the localized load, where the conventional prosthesis presented superior results in all regions (averages ranging from 47.35 to 8.30), followed by the prosthesis associated with the implant, the prosthesis associated with the rigid attachment and, with the prosthesis associated with the semi-rigid attachment. Based on the data obtained, it may be concluded that the conventional RPD presented a balanced stress distribution in the three regions analyzed, and when associated with the semi-rigid attachment, it presented a more favorable behavior than that associated with the rigid attachment.

Um dos maiores desafios para os cirurgiões-dentistas consiste na reabilitação de pacientes com extremidade livre classe I e classe II de Kennedy, devido à ocorrência inadequada de tensão em torno das estruturas de suporte das próteses removíveis convencionais durante o processo da mastigação. O objetivo deste trabalho foi analisar comparativamente a distribuição de tensão em diferentes soluções protéticas. Para essa análise, foram confeccionados quatro Modelos Fotoelásticos (MF) simulando um arco classe I de Kennedy, e tendo como dentes remanescentes do dente 34 ao 44. Em todos os modelos, os dentes 33, 34, 43 e 44 receberam coroas metálicas. Além das coroas, o modelo A (MFA) recebeu uma Prótese Parcial Removível (PPR) convencional, o modelo B (MFB) recebeu uma PPR associada a encaixe semirrígido, o modelo C (MFC) recebeu uma PPR associada a encaixe rígido e o modelo D (MFD) recebeu uma PPR associada a implante e encaixe rígido. Foram aplicadas cargas uniformemente distribuídas e localizadas no último dente artificial das próteses. Baseado nos resultados da carga distribuída, a prótese convencional apresentou os melhores resultados para todas as regiões (médias variando entre 25,70 e 17,80), seguida da prótese associada ao implante, a prótese associada ao encaixe rígido e, finalmente, com a prótese associada ao encaixe semirrígido. O mesmo resultado pode ser observado na carga localizada, onde a prótese convencional apresentou resultados superiores em todas as regiões (médias variando entre 47,35 e 8,30), seguida da prótese associada ao implante, a prótese associada ao encaixe rígido e, finalmente, com a prótese associada ao encaixe semirrígido. Baseado nos dados obtidos pôde-se concluir que a PPR convencional apresentou uma distribuição equilibrada de tensões nas três regiões analisadas e, quando associado à fixação semi-rígida, apresentou um comportamento mais favorável do que aquele associado à fixação rígida.

Influence of aging on bond strength of artificial teeth to denture base acrylic resins

Aim: The aim of this study was to evaluate the bond strength of artificial teeth to different types of denture base resins when submitted to thermomechanical cycling (TMC). Methods: Sixty artificial mandibular first molars (Trilux, Vipi) were randomly divided into 3 groups according to denture base acrylic resins (Vipi Wave, Vipi Cril, and Vipi Cril Plus, Vipi). The teeth were fixed onto self-polymerizing acrylic resin bars (0.5 cm2 cross-section x 2 cm height), and the set was included in a metal flask using dental stone/silicone. After the dental stone was set, the bar was removed, and the denture base resin was packed and processed according to the group studied (Vipi Wave: 180 W/20 minutes + 540W/5 minutes; Vipi Cril and Vipi Cril Plus: Water bath at 74ºC for 9h). After polymerization, the samples were divided into 2 groups (n=10), according to the TMC treatment received (simulation of 5 years of mastication or not). The samples were submitted to tensile bond strength test (1 mm/min), and the data (MPa) were statistically analyzed (2-way ANOVA, Bonferroni, α=0.05). The fracture interfaces were evaluated using a stereomicroscope (50x). Results: The bond strength results showed no statistically significant difference (p>0.05) between the resins studied. TMC was significant (p<0.05), demonstrating lower values for the bond strength of artificial teeth to Vipi Cril Plus. The predominant fracture type was cohesive in resin. Conclusions: It was concluded that there is no difference in bond strength between artificial teeth and the resins used for denture base. However, TMC decreases the bond strength values of artificial teeth and crosslink thermo-polymerizable acrylic resin

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.

Effect of surface treatment of prefabricated teeth on shear bond strength of orthodontic brackets

ABSTRACT Objective: The aim of this in vitro study was to evaluate and compare the effects of grinding, drilling, sandblasting, and ageing prefabricated teeth (PfT) on the shear bond strength (SBS) of orthodontic brackets, as well as the effects of surface treatments on the adhesive remnant index (ARI). Methods: One-hundred-ninety-two PfT were divided into four groups (n = 48): Group 1, no surface treatment was done; Group 2, grinding was performed with a cylindrical diamond bur; Group 3, two drillings were done with a spherical diamond bur; Group 4, sandblasting was performed with 50-µm aluminum oxide. Before the experiment, half of the samples stayed immersed in distilled water at 37oC for 90 days. Brackets were bonded with Transbond XT and shear strength tests were carried out using a universal testing machine. SBS were compared by surface treatment and by ageing with two-way ANOVA, followed by Tukey's test. ARI scores were compared between surface treatments with Kruskal-Wallis test followed by Dunn's test. Results: Surface treatments on PfT enhanced SBS of brackets (p< 0.01), result not observed with ageing (p= 0.45). Groups II, III, and IV showed higher SBS and greater ARI than the Group 1 (p< 0.05). SBS was greater in the groups 3 and 4 (drilling, sandblasting) than in the Group 2 (grinding) (p< 0.05). SBS and ARI showed a positive correlation (Spearman's R2= 0.57; p< 0.05). Conclusion: Surface treatment on PfT enhanced SBS of brackets, however ageing did not show any relevance. Sandblasting and drilling showed greater SBS than grinding. There was a positive correlation between SBS and ARI.

RESUMO Objetivo: o objetivo desse estudo in vitro foi avaliar e comparar os efeitos de desgastes, perfurações, jateamento e envelhecimento de dentes pré-fabricados (Dpf) na resistência ao cisalhamento (RC) de braquetes ortodônticos, bem como os efeitos dos tratamentos de superfície no índice de adesivo remanescente (ARI). Métodos: 192 Dpf foram divididos em quatro grupos (n = 48): Grupo 1, sem tratamento; Grupo 2, desgaste de sulcos com broca diamantada cilíndrica; Grupo 3, duas perfurações com broca diamantada esférica; e Grupo 4, jateamento com partículas de óxido de alumínio de 50µm. Antes do experimento, metade das amostras ficou imersa em água destilada a 37oC durante 90 dias. Os braquetes foram colados com Transbond XT e os testes de cisalhamento foram realizados com uma máquina universal de ensaios. A RC foi comparada, por tratamento de superfície e por envelhecimento, utilizando-se análise de variância e teste de Tukey. Os escores ARI foram comparados entre os tratamentos de superfície usando o teste Kruskal-Wallis e o teste de Dunn. Resultados: os tratamentos de superfície aumentaram a RC dos braquetes (p < 0,01) e o envelhecimento não aumentou a RC (p = 0,45). Os Grupos 2, 3 e 4 mostraram maior RC e maior ARI do que o Grupo 1 (p < 0,05). A RC foi maior nos Grupos 3 e 4 (perfuração, jateamento) do que no Grupo 2 (desgaste) (p < 0,05). RC e ARI apresentaram correlação positiva (R2 = 0,57; p < 0,05). Conclusão: o tratamento de superfície dos Dpf aumentou a RC dos braquetes; porém, o envelhecimento não foi relevante. O jateamento e a perfuração mostraram maior RC do que o desgaste. Existe uma correlação positiva entre RC e ARI.

El cráneo de la mirada mágica y dentadura de jade / The skull of the magic glimpse and its jade teeth

Se presentan dos esculturas prehispánicas de la cultura azteca, la primera en forma de cráneo a la cual se le tallaron y colocaron ojos de diferentes tipos de piedra, también una dentadura completa y bien alineada hecha de jade. En la zona del occipital se distingue el grabado de un rey desconocido, el cual porta un arete, un penacho y un cetro. La segunda escultura es una charola de piedra tallada con incrustaciones de piedras preciosas de jade y rubí que muestra la imagen del mismo rey sostenida por tres personajes parcialmente desdentados padeciendo de dolor dental. Estos eventos demuestran la importancia de la salud bucal en la población prehispánica, particularmente en la cultura azteca, al igual que la relevancia de los aspectos mágicos y religiosos en torno a la muerte.

It is described a couple prehispanic carved solid stone sculptures of theAztec culture, the fi rst one with a human skull shape, with carved andmounted stone eyes, as well as a complete and fi ne lined jade denture.It is also remarked on its occipital area a fi gure of carved unknownking, wearing a mobile stone earring, a feather cap, and a cane. Thesecond stone sculpture is a carved stone plate with jade and ruby carvedmounted stones. This sculpture also shows the same mentioned kingimage, which is supported by three no complete dental (toothless) maleservants, that resemble the three men suff ering dental discomfort. Thesecouple sculpture pieces show the magical and religious aspects of themighty importance of the death to the Aztecs.

Estabelecimento de uma proporção entre largura de dentes artificiais anteriores, medidos em curva e em linha reta / Establishing a ratio between the width of anterior artificial teeth measured in curved and straight configurations

Objetivo: estabelecer uma proporção única de redução entre a medida da largura dos seis dentes artificiais anteriores superiores, em curva e em linha reta. Material e métodos: foi utilizado um dispositivo pré-fabricado, simulando o plano de cera superior, no qual foram montados os dentes (Premium, Heraeus-Kulzer Inc. ­ Hanau, Alemanha) nos seguintes modelos: T2, O2, R2, S2, S4, O4, S6, R4, R6, T4 e T6. Em seguida, a largura em curva entre os dentes anteriores montados foi medida com uma régua flexível, tendo como referência a face distal dos caninos. A partir dos dados obtidos (mm) e dos valores das medidas fornecidos na carta molde do fabricante, realizou-se o cálculo da proporção entre essas duas medidas para cada modelo de dentes. Resultados: verificou-se redução entre a medida em curva e a medida em linha reta, variando de 4% a 19% para todos os tipos de modelos estudados. Assim, não foi possível estabelecer uma porcentagem padrão única de redução para todos os tipos de dentes do fabricante. Porém, agrupando-se a redução em milímetros, observou-se uma redução variável entre os modelos em curva e em linha reta: 2 mm para o modelo T2; 3 mm para os modelos O2, R2, S2 e S4; 4 mm para os modelos O4 e S6; 5 mm para os modelos R4, R6 e T4; e 9 mm para o modelo T6. Conclusão: é possível estabelecer uma redução aproximada (em mm) entre uma medição em curva e reta na seleção de dentes artificiais Premium/Heraeus-Kulzer.

Objective: this study aimed to establish a single rate reduction between the measurement of the width of the six artificial anterior upper teeth, in curved and straight configurations. Methods: for this, a prefabricated device simulating the upper wax rim was used and received artificial teeth (Premium, Heraeus-Kulzer Inc., Hanau, Germany) from T2, O2, R2, S2, S3, O4, S6, R4, R6, T4, and T6. Next, the width of the six anterior teeth in curvature was measured from the distal of both canines. After, based on the mold chart of the manufacturer, the ratio between the straight and curved configurations was generated. Results: there was a 4% to 19% in reduction between the curved and straight configurations. A single reduction percentage was not obtained for all tooth forms. However, the reductions were 2 mm for T2, 3 mm for O2, R2, S2 and S4; 4 mm for O4 and S6; 5 mm for R4, R6, and T4; and 9 mm for T6 models. Conclusion: it is possible to establish an approximated reduction (in mm) between the curved and straight configurations for Premium/Heraeus-Kulzer artificial teeth.