Tecnologia digital em próteses totais: propriedades dos materiais CAD-CAM e desenvolvimento de uma patente de inovação para simplificação do fluxo de trabalho / Digital technology in complete dentures: properties of CAD-CAM materials and development of an innovation patent to simplify the workflow

Recursos digitais, como a manufatura subtrativa (fresagem CAD-CAM) e a manufatura aditiva (impressão 3D) podem promover significativos avanços, reduzindo o tempo e o custo de produção de próteses totais (PTs). Assim, este estudo objetiva investigar as características superficiais (rugosidade e ângulo de contato), propriedades mecânicas (resistência mini-flexural) e a adesão de biofilme sobre polímeros de PMMA pré-polimerizado para fresagem CAD-CAM e sobre resinas para impressão 3D utilizados na fabricação de bases de PTs, bem como propor um fluxo de trabalho inovador para abreviar e simplificar as etapas de confecção de PTs. Para a análise in vitro, foram fabricados um total de 60 discos e 40 barras distribuídas igualmente em quatro grupos: fresagem CAD-CAM (GF), impressão 3D (GI) e PMMA convencional termopolimerizado por ciclo longo (GCL) ou por energia de micro-ondas (GCM). A rugosidade foi determinada pelo valor de Ra; o ângulo de contato foi medido pelo método da gota séssil; o teste de resistência à mini-flexão foi obtido por teste de flexão de três pontos, enquanto o comportamento frente à formação de biofilme foi analisado através da adesão de biofilme de C. albicans. Os dados foram analisados por meio de estatística descritiva e analítica (α = 0,05). Os resultados mostraram que o GI apresentou a maior rugosidade superficial (Ra: 0,317 ± 0,151µm) e os menores valores de resistência à miniflexão (57,23 ± 9,07MPa) e o GF apresentou a menor adesão de biofilme de C. albicans (log UFC/mL: 3,74 ± 0,57) e maior média de resistência à mini-flexão (114,96 ± 16,23 MPa). Não houve diferença estatística entre o GF e os grupos convencionais para rugosidade, ângulo de contato e resistência à mini-flexão. A patente de inovação desenvolvida estabeleceu um novo fluxo de trabalho para confecção de próteses totais através de um protocolo de três consultas em que foram feitas as moldagens anatômicas na 1ª sessão, juntamente com o registro do suporte labial, plano oclusal e linhas de referência para subsidiar a montagem dos dentes superiores. Uma prótese-teste foi confeccionada por meio de procedimentos convencionais ou CAD-CAM e avaliada na 2ª consulta, permitindo observar o resultado estético, executar a moldagem funcional e realizar o registro da relação maxilo-mandibular, fornecendo referências precisas para a confecção da prótese inferior. Com base nos resultados da fase in vitro deste estudo, os corpos-de-prova obtidos a partir de disco para fresagem CAD-CAM apresentaram resistência flexural e propriedades superficiais semelhantes às resinas convencionais e mostraram um comportamento inibidor da adesão de C. albicans, enquanto os espécimes produzidos por impressão 3D exibiram a menor resistência à flexão e a maior rugosidade da superfície. O dispositivo inovador apresentado para a execução das etapas clínicas relacionadas à fabricação de PTs mostrou-se efetivo para abreviar e simplificar as técnicas disponíveis, apresentando confiabilidade e previsibilidade para produção de PTs em número de sessões reduzido (AU).

Digital features like subtractive and additive manufacturing can promote breakthroughs by reducing the time and cost of making complete dentures (CDs). Thus, this study aims to investigate surface characteristics (roughness and contact angle), mechanical properties (mini-flexural strength), and biofilm adhesion on computer-aided design/computer-aided manufacturing (CAD-CAM) PMMA polymer, and threedimensional (3D) printed resin for denture´s base fabrication as well as to propose an innovative workflow. For in vitro analysis, a total of 60 discs and 40 rectangular specimens were fabricated from one CAD-CAM pre-polymerized PMMA disc (GF), one 3D-printed (GI), and two conventional heat-polymerized (GCL and GCM) materials for denture base fabrication. Roughness was determined by the Ra value; the contact angle was measured by the sessile drop method; the mini-flexural strength test was a three-point bending test while the biofilm formation inhibition behavior was analyzed through C. albicans adhesion. The data were analyzed using descriptive and analytical statistics (α = 0.05). Results showed that GI specimens presented the highest surface roughness (Ra: 0.317 ± 0.151 µm) and lowest mini-flexural strength values (57.23 ± 9.07 MPa) and the GF showed the lowest C. albicans adhesion (log CFU/mL: 3.74 ± 0.57) and highest mini-flexural strength mean (114.96 ± 16.23 MPa). There was no statistical difference between GF and conventional groups for roughness, contact angle, and mini-flexural strength. In turn, the presented novel workflow for complete dentures fabrication reached a three appointments protocol in which preliminary impressions were made in the 1st session, all together to maxillary registration of lip support, occlusal plane, and reference lines for teeth arrangement. A trial denture was manufactured and evaluated by the 2nd appointment through conventional or CAD-CAM procedures, allowing esthetics evaluation, final impression, and maxillomandibular relationship record and providing precise references for final dentures fabrication. Based on the findings of this in vitro study, GF presented surface and mechanical properties similar to conventional resins and show improved behavior preventing C. albicans adhesion, while GI specimens exhibited the lowest flexural strength, and highest surface roughness. The proposed device for CD´s fabrication clinical procedures reached feasibility and by simplifying available techniques, this protocol could achieve reliability and predictability to produce complete dentures with reduced working time (AU).

The Development of Nonanatomic Denture Occlusion: Part III.

Part III of this four-part series about nonanatomic denture tooth development traces the evolution of this movement from the mid-1930s through the World War II era up to the early 1950s. By this time, the general preference for posterior denture occlusion had shifted from anatomic to nonanatomic teeth, and all the major denture tooth manufacturing companies listed at least one nonanatomic design in their inventories.

The Development of Nonanatomic Denture Occlusion: Part IV.

This fourth and final part of a four-part series concerned with the development of nonanatomic denture occlusion follows nonanatomic tooth design from the time of Victor Sears' first nonanatomic tooth patent through the end of the 20th century. Part IV concentrates on nonanatomic teeth developed during the last five decades of the 20th century. Many of the designs featured in this series exhibited genius, while others are pure nonsense. Sears claimed that a new nonanatomic tooth design appeared every 9 months on average during the first 30 years of nonanatomic tooth production. Many current nonanatomic tooth patents are further refinements of those earlier designs.

The Development of Nonanatomic Denture Occlusion: Part II.

This second part of a four-part series concerned with the development of nonanatomic denture occlusion follows nonanatomic tooth design from the time of Victor Sears' first nonanatomic tooth patent through the mid-1930s. Many of the designs featured in this series exhibit genius, while others are pure nonsense. Sears claimed that a new nonanatomic tooth design appeared every 9 months on average during the first 30 years of nonanatomic tooth production. Many current nonanatomic tooth patents are further refinements of those earlier designs. Part II reviews pioneering designs that appeared during the first dozen or so years of this paradigm shift in denture occlusion philosophy.

Próteses totais mucossuportadas ofertadas na atenção primária à saúde em Belo Horizonte, MG: avaliação após 5 anos de uso / Dentures mucus-supported offered in primary health care in Belo Horizonte, MG: evaluation after 5 years of use

A prótese total (PT) é o tratamento reabilitador mais utilizado em pacientes edêntulos e pode resgatar a estética, a função mastigatória e a fonação. O levantamento das condições de saúde bucal da população brasileira (2011) revelou que 69% da população adulta e quase 99% dos idosos usavam ou necessitavam de algum tipo de prótese dentária. A inclusão da reabilitação protética no âmbito da Atenção Primária em Saúde é uma das diretrizes da Política Nacional de Saúde Bucal (2004). Esse serviço se iniciou em Belo Horizonte em julho de 2010 com a oferta de próteses totais (PTs) e próteses parciais removíveis (PPR) de acrílico. O objetivo desse estudo foi avaliar a associação entre o uso das próteses totais mucossuportadas ofertadas na Atenção Primária à Saúde após um e cinco anos de inserção com a qualidade técnica dessas próteses e a satisfação dos usuários com as mesmas). Foi realizado um estudo de seguimento com amostra de 233 usuários, aleatoriamente, selecionada do universo de 572 usuários que receberam o par de próteses totais em 2011. Avaliou-se o uso de prótese total superior e inferior, que resultou na variável dependente dicotômica: não uso; uso do par ou de uma das próteses. A qualidade técnica foi avaliada quanto a arranjo dos dentes anteriores, espaço funcional livre, estabilidade, retenção e extensão da prótese mandibular, oclusão estática e dinâmica. A integridade das próteses considerou presença de fratura da base e bordos irregulares. A avaliação da satisfação com relação a dor, retenção, estabilidade, conforto, mastigação, fala e aparência resultou em um escore de 0 a 100, que foi categorizado adotando-se o ponto de corte 70 em: insatisfeito ou muito satisfeito/satisfeito. Foram avaliadas as seguintes co-variáveis: idade, sexo, situação conjugal, anos de estudo e renda familiar, uso pregresso de próteses totais, tempo da perda de dentes superiores e frequência de retorno ao cirurgião-dentista posterior à entrega das próteses. As associações foram testadas por análise de regressão logística, o efeito das variáveis no uso de prótese total ao longo dos períodos propostos foi estimado por modelos de regressão logística com efeitos aleatórios no intercepto. A coleta dos dados por meio de entrevista e exame da cavidade bucal e das próteses foi realizada entre novembro de 2012 a janeiro de 2013 e de julho a outubro de 2016. As examinadoras foram previamente calibradas e a concordância intra e interexaminadoras foi calculada por Kappa ponderado e os coeficientes foram superiores a 0,81. A taxa de participação foi de 97,8% (228) em um ano e de 50% (114) em cinco anos pós a instalação das próteses. Não houve diferença estatisticamente significativa entre respondentes e não respondentes com relação a sexo, idade, escolarização, anos de estudo, frequência de retorno ao cirurgião-dentista e satisfação com a prótese. Entretanto, a qualidade técnica da prótese nos critérios estabilidade, oclusão estática e dinâmica foi menor entre os não respondentes. Após um ano, 64,9% usavam o par de próteses, 14% usavam uma das próteses e 21,1% não usavam. Já em cinco anos, 64,1% usavam o par de próteses, 14,9% usavam pelo menos uma das próteses e 21,0% não usavam. Observou-se que entre os indivíduos que usavam o par de próteses em cinco anos, 86,3% já usavam o par em um ano e entre os que não usavam 37,5% deixaram de usá-las após o primeiro ano. Após cinco anos, em relação à qualidade técnica das próteses, cerca de 70% foram consideradas adequadas para arranjo dos dentes anteriores, espaço funcional livre, estabilidade da prótese mandibular, oclusão estática e oclusão dinâmica. Mais de 80% das próteses mandibulares apresentaram problemas de retenção e extensão da borda. A quase totalidade das próteses não apresentava problemas de integridade. Quanto à satisfação com as próteses, 57,02% dos usuários estavam muito satisfeitos/satisfeitos. Os fatores de satisfação melhores avaliados foram estética, fala e conforto. A retenção da prótese total inferior gerou a maior insatisfação. Foi encontrada associação entre uso de próteses totais após um ano de inserção em indivíduos cujas próteses apresentavam estabilidade, espaço funcional livre entre 1 e 4 mm e estavam satisfeitos/muito satisfeitos. Após cinco anos de inserção, o uso das próteses totais foi associado à estabilidade da prótese mandibular e à satisfação. As próteses ofertadas satisfazem a população assistida e a maioria apresenta qualidade técnica e integridade. Maior uso após cinco anos de inserção foi observado entre os usuários satisfeitos e com próteses mandibulares estáveis, esse uso foi maior entre os indivíduos que já usavam após um ano de inserção, indicando maior abandono no primeiro ano. Protocolos de acompanhamento dos pacientes após a entrega das próteses totais devem ser implantados no âmbito dos serviços públicos de saúde para favorecer a adesão e sucesso do tratamento reabilitador

The total prosthesis (TP) is the most used rehabilitating treatment in edentulous patients and it may rescue the aesthetics, the masticatory function and the phonation. The survey of the oral health conditions of the Brazilian population (2011) revealed that 69% of the adult population and almost 99% of the elderly used or needed some sort of dental prosthesis. The inclusion of the prosthetic rehabilitation in the scope of Basic Assistance in Health is one of the guidelines of the National Policy in Oral Health (2004). This service was started in Belo Horizonte in July 2010 with the offer of total prosthesis (TPs) and partial removable prosthesis (PRP) of acrylic. The aim of this study was to evaluate the association between the uses of the total prosthesis mucus-supported offered in the Primary Care in Health after one and five years of the insertion with the technical quality of these prostheses and the satisfaction of the users towards them. A follow-up study was carried out with a sample of 233 users at random, selected within a universe of 572 users who had received the pair of full prosthesis in 2011. The use of the total prosthesis both inferior and superior was evaluated, which resulted in the dichotomous dependent variable: no use; use of the pair or of one of the prosthesis. The technical quality was evaluated with regards to the arrangement of the anterior teeth, free functional space, stability, retention and extension of the mandibular prosthesis, static and dynamic occlusion. The integrity of the prosthesis considered the presence of fracture of the basis and irregular edges. The evaluation of the satisfaction concerning the pain, retention, stability, comfort, mastication, speech and appearance resulted in a score ranging from 0 to 100, which was categorized adopting the cut-off point of 70 to dissatisfied or very satisfied/satisfied. The following co-variables were assessed: age, gender, marital status, years of schooling and family income, previous use of total prosthesis, time for upper teeth loss and frequency of visits to the dental surgeon after the placement of the prosthesis. The associations were tested through a logical regression analysis; the effect of the variables in the use of total prosthesis along the proposed periods was estimated via logistic regression models with random effects in the intercept. The data collection through interviews and examination of the oral cavity and the prosthesis was carried out between November 2012 to January 2013 and from July to October 2016. The examiners were previously calibrated and the agreement intra and inter-examiners was calculated using pondered Kappa and the coefficients were superior to 0,81. The participation rate was 97,8% (228) in one year and 50% (114) in five years after the placement of the prosthesis. There was no statistically significant difference between the responsive and the non-responsive concerning gender, age, schooling, frequency of visits to the dental surgeon and satisfaction towards the prosthesis. However, the technical quality of the prosthesis within the criteria of stability, static and dynamic occlusions was lower among the non-responsive. After one year, 64,9% used the pair of prosthesis, 14% used one of the prosthesis and 21,1% did not use any. In five years, 64,1% used the pair of prosthesis, 14,9% used at least one of the prosthesis and 21,0% did not use any. It was observed that among the subjects who used the pair of prosthesis in five years, 86,3% already used the pair in one year and among those who did not use them 37,5% abandoned their use after the first year. After five years, regarding the technical quality of the prosthesis, around 70% were considered adequate for the arrangement of the anterior teeth, free functional space, and mandibular prosthesis stability, static and dynamic occlusion. More than 80% of the mandibular prosthesis presented retention problems and ridge extension. The almost full totality of the prosthesis did not present integrity problems. Concerning the satisfaction towards the prosthesis, 57,02% of the users were very satisfied/satisfied. The satisfaction factors better evaluated were aesthetics, speech and comfort. The inferior full prosthesis retention resulted in the higher level of dissatisfaction. Associations between the uses of full prosthesis were found after one year of placement in subjects whose prosthesis presented stability, free functional space ranging between 1 and 4 mm and were satisfied/very satisfied. After five years of placement, the use of full prosthesis was associated to the stability of the mandibular prosthesis and satisfaction. The offered prosthesis satisfies the assisted population and the majority presents technical quality and integrity. A greater use after five years of placement was observed among the satisfied users and those who had stable mandibular prosthesis; this use was higher among the subjects who already used that one year after the placement, indicating a greater rate of abandonment in the first year. Follow-up protocols of the patients after the placement of the full prosthesis must be implemented in the scope of public health services to favor the adhesion and success of the rehabilitating treatment

TRENDS IN COMPLETE DENTURE IMPRESSIONS IN PAKISTAN.

BACKGROUND: Multiple materials and techniques have been reported for complete denture impressions in literature. The aim of the study was to assess the trends in complete denture impression materials and techniques among general dental practitioners (GDP) and specialists (SP) in Pakistan. METHODS: In this cross-sectional study, self-designed-structured questionnaires were distributed among 500 dentists in Pakistan. The three-part questionnaire enquired about the demographic features, preferred impression materials, impression techniques and related procedures commonly used in their clinical practice. A comparison between the responses of SP and GDP was also drawn. Frequency distribution and Chi-square test were performed to compare the responses. RESULTS: A total of 294 questionnaires were completed at a response rate of 58.8%. 75% of GDP used alginate for primary impressions and 66% of SP preferred impression compound for the same. A majority of both SP and GDP favoured the used of custom trays (SP 81%, GDP 85%) and selective pressure technique (SP 84%, GDP 53%) for final impression. However, 85% of GDP used zinc-oxide eugenol and 62% of SP favoured elastomeric materials for the same. Most of the SP and GDP used chemical cured resin custom trays (SP 54%, GDP 75%), however, 86% of SP used spaced trays and almost 60% of GDP preferred close-fitting trays. CONCLUSIONS: The practice of GDP and SP with regards to CD impression materials and techniques differed significantly. Continued education and training for GDP and SP with respect to procedures and techniques related to CD is recommended.

União dente-implante: é possível / Tooth-implant connection: is it possible

Os implantes dentários têm sido utilizados com sucesso, tanto no tratamento de pacientes totalmente edêntulos quanto daqueles parcialmente edêntulos. Entretanto, eles não possuem as mesmas características que os dentes naturais. Este trabalho busca, portanto, apresentar uma revisão de literatura sobre a união de dentes e implantes em uma mesma prótese...

The future of complete dentures in oral rehabilitation. A critical review.

Based on available investigations and current trends in oral rehabilitation published in the dental literature, an attempt is made to describe the possible future role of complete dentures. For edentulous patients, complete dentures have for long been the only prosthodontic treatment option. Whereas a large number of edentulous patients report satisfaction with denture usage, a smaller number are unable to adapt; for such patients, sophistication of clinical and technical processes or quality of denture-supporting tissues, appear to have little influence on patient-perceived outcomes. Since the 1980s, osseointegrated dental implants have dramatically improved the therapeutic possibilities, especially so for maladaptive patients. Those able to access such treatment can expect significant improvements in oral functional status and quality of life. While there is a downward trend in edentulism in several countries, it is region-specific, confirming the overriding influence of socio-economic factors on health status. In most societies, despite ageing populations, the need for complete dentures is not likely to reduce in the near future. Whereas a two- or even a one-implant overdenture for the edentulous mandible is increasingly regarded as a minimum standard of care in many developed countries, its routine prescription for the majority in the world who are disadvantaged is unrealistic; for them, even 'low-tech' therapies like conventional dentures are beyond their reach. Improving the conventional management of edentulous patients is a necessity and requires a keener focus by researchers, educators and clinicians in the developed world on the needs of populations with fewer resources.

Evaluación del efecto de prensado en prótesis totales maxilares sobre la movilidad de los dientes artificiales, en función del tipo de inclusión / Evaluation of the effect of full denture pressing on the artificial teeth mobility, in function of two type of flasking

El presente trabajo evaluó el movimiento de los dientes artificiales en prótesis totales maxilares, sometidas a diversas presiones durante el prensado y el efecto de este en relación al material usado en la inclusión. Treinta y seis réplicas de prótesis totales previamente confeccionadas, fueran divididas en seis grupos: Los grupos G1,G2 y G3 fueron incluidos con yeso tipo III, a una presión de 800, 1.000 y 1.250 kgf respectivamente y los grupos S1, S2 y S3 fueron incluidos con una barrera de silicona y yeso, a una presión de 800, 1.000 y 1.250kgf, respectivamente. Las prótesis fueron medidas en puntos demarcados previamente en los segundos molares, premolares e incisivo central con el programa de computación gráfica (AutoCad 2000), después de cada etapa: encerado, polimerización y emuflado. La comparación entre estas dos fases permitió observar que: en los grupos (G1 y S1) donde se utilizó la menor presión (800 kgf) ocurrieron las mayores alteraciones en el posicionamiento de los dientes artificiales y que el grupo que mostró menores alteraciones fue cuando se utilizó 1.250 kgf de presión y la inclusión fue con yeso (AU)

The present study evaluated artificial teeth movement in complete dentures, submitted to different flasking loading and the effect of these loading pressures on the material used in the flasking procedure. Thirty-six dentures were fabricated and equally divided into six groups: Groups G1, G2 and G3 were processed with type III gypsum and 800, 1000 and 1250 kgf loading pressures, respectively, and groups S1, S2 and S3 were processed with silicone barrier and 800, 1000 and 1250 kgf loading pressures, respectively. In order to evaluate the artificial teeth movement, measurements were performed from previously determined points down in the second molars tips and in the second pre-molars cusps and in the central incisor. Those points were scanned (Scan Jet 6100C - Hewlett Packard) and then the measurements were performed and analyzed through the use of the AutoCad 2000 software, during the wax and the post-polymerization phases. The comparison between these two phases allowed the following observations: in groups (G1 and S1) where less loading pressure was used (800 kgf), the movements in the artificial teeth positions were the highest, and the group that presented the lowest changes was the one processed with type III gypsum and 1250 kgf loading pressure (AU)

Will there be a need for complete dentures in the United States in 2020?

Currently, there is much speculation among dental educators that the need for complete dentures will decline markedly in the future and that complete denture training should be removed from the dental curriculum. Estimates based on national epidemiologic survey data indicate that edentulism has declined by 10% every decade and that only 90% of edentulous adults obtain and wear complete dentures. However, when the number of adults in each specific age group is multiplied by the percentage who need a complete maxillary or mandibular denture, the results suggest that the adult population in need of 1 or 2 complete dentures will increase from 33.6 million adults in 1991 to 37.9 million adults in 2020. The 10% decline in edentulism experienced each decade for the past 30 years will be more than offset by the 79% increase in the adult population older than 55 years. The clinical implications of these findings are twofold: First, practicing dentists will find that a sizable minority of the patient population will continue to need complete denture services; and second, if training in complete denture prostheses is eliminated from the dental education curriculum, millions of patients will be forced to seek denture services from alternative providers.

Alteraçöes radiográficas da regiäo maxilo-mandibular em pacientes edêntulos / Radiographic alterations on the maxillary region in edentulous patients

Cem pacientes desdentados totais foram avaliados através de radiografias panorâmicas e periapicais antes da confecçäo de novas próteses totais duplas. Achados radiográficos foram encontrados em 86 por cento dos pacientes, sendo que 3,5 por cento destes pacientes necessitaram de tratamento antes da confecçäo das novas próteses totais. Estes dados confirmam a importância do exame radiográfico em pacientes desdentados totais, que väo confeccionar pela primeira vez ou que väo trocar próteses totais

Current trends in removable prosthodontics.

BACKGROUND: This article discusses trends in the demographics and treatment of the edentulous patient. It is clear that there still is a tremendous need for removable-prosthodontic services today. While the basic process of making dentures has changed little over the past several decades, new materials and techniques can help laboratories and clinicians provide functional, esthetic restorations that offer exceptional value to patients. Implant treatment is a tremendous adjunct to removable prosthodontics in the treatment of edentulous patients, but it is not within the financial reach of all dental patients. CLINICAL IMPLICATIONS: The clinical skills required to deliver excellent complete denture care are also paramount to successful implant prosthodontics (fixed and removable) and esthetic dentistry. Even so, the opportunities to develop these skills and the interest appear to be decreasing at the same time that the need is projected to increase. In service to our patients, the profession must examine this trend closely.

Caracterizaçäo das bases das próteses removíveis total e parciais: parte II / Caracterization of the complete and partial removable prosthetics basic

Através desta pesquisa os autores desenvolveram uma metodologia para obtençäo de resinas acrílicas termopolimerizáveis nas cores mais semelhantes àquelas observadas na pigmentaçäo natural da mucosa bucal. Os materiais utilizados como pigmentos säo de baixo custo e facilmente encontrados nos próprios laboratórios de prótese. Desta forma, com a elaboraçäo de uma ampla escala de cores pretende-se que a prática de caracterizaçäo das bases de próteses totais e parciais removíveis se torne um procedimento rotineiro entre técnicos e cirurgöes-dentistas, resultando num melhor e mais completo atendimento aos anseios estéticos, tanto pelos pacientes como pelos profissionais

The results of a brief survey of complete denture prosthodontic techniques in predoctoral programs in North American dental schools.

A brief mail survey of North American dental schools was undertaken to ascertain the current techniques in complete denture prosthodontics regarding preliminary and final impressions, record bases, and denture teeth. Of the 64 schools surveyed, 54 responded (84%). Seventy-four percent of the respondents used only irreversible hydrocolloid (alginate) for their preliminary impressions; 15% used only modeling plastic impression compound. Eighty-one percent used only modeling plastic impression compound for border molding of the final impression tray; 7% used only polyether impression material. Forty-eight percent used only polysulfide rubber (PR) impression material for their final impression material; 4% used only polyether impression material. Only 1 school still used shellac as one of its materials for record bases. Thirty-five percent used only Triad; 35% used only acrylic resin; 24% used both of these materials. Thirteen percent of responding schools used only nonanatomic teeth. The majority (54%) used all three options (nonanatomic, semianatomic, and anatomic). Eleven percent used lingualized occlusion. As compared with a survey performed in 1985, the use of irreversible hydrocolloid as a preliminary impression material, the use of visible light-cured resins for record bases, and the use of anatomic teeth have increased. The use of plastic impression compound for border molding and PR as the final impression material has largely remained the same.

Caracterizaçäo das bases das próteses totais e parciais removíveis / Characterization of denture bases and removable partial prosthodontics

O objetivo deste trabalho foi analisar, com base na revisäo da bibliografia, as diversas técnicas desenvolvidas para caracterizaçäo da cor das bases de próteses totais e parciais removíveis e avaliar as diferentes formas de obtençäo de resinas nas cores mais semelhantes àquelas encontradas na pigmentaçäo natural da gengiva e da mucosa bucal