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RESUMEN El diseño asistido por computadora y la fabricación asistida por ordenador (CAD-CAM, por sus siglas en inglés) se ha aplicado en odontología para la confección y el análisis de diversos tratamientos dentales. Inicia con la captura de imágenes a través de escáneres intraorales, contando con diversos tipos de softwares y sistemas de exportación de imágenes y tecnología. Las ventajas de este flujo de trabajo digital son el mejor ajuste, el empleo de menor tiempo clínico y la celeridad en tratamientos dentales, además de que brinda una mayor practicidad en el uso de los cirujanos dentistas. La precisión que brinda es clínicamente aceptable en comparación con los métodos convencionales, por lo cual existe suficiente evidencia para su validez; sin embargo, se debe tener en cuenta que diversos factores pueden alterar el resultado, como la experiencia del operador, el tipo de escáner, el tipo de software, la actualización del software, el principio de escaneo del escáner, el ambiente, la secuencia de escaneo y las estructuras bucales. El presente artículo de revisión tiene como objetivo analizar la literatura sobre las diferentes características y propiedades que presentan los escáneres intraorales en la actualidad, así como la evidencia de los posibles beneficios y la precisión de las técnicas de impresión digital frente a las técnicas de impresión convencionales.

ABSTRACT Computer-aided design and computer-aided manufacturing (CAD-CAM) has been applied in dentistry for the preparation and analysis of various dental treatments. It starts with capturing images through intraoral scanners, having different types of software and image export systems and technology. The advantages of this digital workflow are the following: better adjustment, shorter clinical time, and speed in dental treatments, in addition to providing greater practicality for dental surgeons. The accuracy he provide is clinically acceptable in comparison with conventional methods, so there is sufficient evidence for their validity; however, it should be taken into account that several factors can alter the result, such as the operator's experience, the type of scanner, the type of software, the software update, the scanning principle of the scanner, the environment, the scanning sequence, and the oral structures. The present review article aims to analyze the literature on the different characteristics and properties that intraoral scanners present today and the evidence of the potential benefits and accuracy of digital impression techniques versus conventional impression techniques.

RESUMO O desenho assistido por computador e o fabrico assistido por computador (CAD-CAM) têm sido aplicados na medicina dentária para a preparação e análise de vários tratamentos dentários. Começa com a captura de imagens através de scanners intraorais, com vários tipos de software e sistemas e tecnologia de exportação de imagens. As vantagens deste fluxo de trabalho digital são as seguintes: melhor ajuste, menor tempo clínico, rapidez nos tratamentos dentários, além de proporcionar maior praticidade no uso dos cirurgiões-dentistas. A precisão que proporcionam é clinicamente aceitável quando comparada com os métodos convencionais, pelo que existem evidências suficientes para a sua validade; no entanto, deve ter-se em conta que vários fatores podem alterar o resultado, tais como a experiência do operador, o tipo de scanner, o tipo de software, a atualização do software, o princípio de digitalização do scanner, o ambiente, a sequência de digitalização e as estruturas orais. Este artigo de revisão tem como objetivo analisar a literatura sobre as diferentes características e propriedades dos scanners intraorais atuais, bem como a evidência dos potenciais benefícios e precisão das técnicas de moldagem digital em comparação com as técnicas de moldagem convencionais.

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ABSTRACT The systematic review of the literature aimed to compare the conventional and digital impression methods for making fixed partial dentures using the current literature and to verify the applicability of the methods in the clinical routine. A search was carried out in the PubMed database using the keywords: Denture, Partial, Fixed and Dental Impression Technique from 2017 to 2022, of studies published in full, in English and free of charge. 520 articles were obtained from PubMed, 501 of which were from 2017 to 2022. After reading the titles and abstracts, 12 articles were excluded. In the end, 6 articles were selected, and 6 articles were later added by cross-reference, totaling 12 articles. Both impressions are good methods to perform impressions in fixed partial dentures, each method having its applications, advantages and disadvantages, and it is up to the dental surgeon to select the impression method to be used, considering the time spent for the impression, the learning curve, the personal, practical and social background, in addition to the cost used to acquire materials, clinical hours and laboratory work in the short and long term.

RESUMO A revisão sistemática da literatura teve como objetivo comparar os métodos de moldagem convencional e digital para confecção de próteses parciais fixas com a literatura atual e verificar a aplicabilidade dos métodos na rotina clínica. Foi realizada uma busca na base de dados PubMed utilizando as palavras-chave: Denture, Partial, Fixed e Dental Impression Technique de 2017 a 2022, de estudos publicados na íntegra, em inglês e gratuitamente. Foram obtidos 520 artigos do PubMed, sendo 501 de 2017 a 2022. Após a leitura dos títulos e resumos, 12 artigos foram excluídos. Ao final, foram selecionados 6 artigos, sendo posteriormente adicionados 6 artigos por referência cruzada, totalizando 12 artigos. Ambas as moldagens são bons métodos para realizar moldagens em próteses parciais fixas, cada método tendo suas aplicações, vantagens e desvantagens, cabendo ao cirurgião-dentista selecionar o método de moldagem a ser utilizado, considerando o tempo gasto para a moldagem, a curva de aprendizado, o background pessoal, prático e social, além do custo de aquisição de materiais, horas clínicas e trabalhos laboratoriais a curto e longo prazo.

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During the fabrication of a complete denture, functional impression is taken. Literature studies show that polydimethylsiloxane (condensation silicone) has not been reported by United States dental schools to perform border molding. Thus, the purpose of this article is to review the functional impression technique when border molding is performed with a laboratory condensation silicone putty.

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The objective of this article is to concisely review the main clinical techniques used to make the functional impression to manufacture a removable partial denture. Through this review, the dentist can develop his clinical knowledge.

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Aim: To analyze the accuracy of extraoral systems (Ceramill Map400+, AutoScan-DS200+, and E2) in full implantprosthetic rehabilitation three-dimensionally. Methods: A metallic edentulous maxilla with four implants was digitalized by a contact scanner (MDX-40 - Roland, control) and used as a control image to compare with other images generated by three laboratory scanners (10 samples per group). Letters identified all the four components: A and D angled 45º, and B and C parallel. The BioCAD software exported the images (.STL) to compare and verify deviations of the analogs on the X, Y, and Z axes. The nonparametric Kruskal-Wallis test and the two-way ANOVA on ranks with a post hoc Tukey test analyzed the data with 5% significance. Results: No statistical differences were observed in the accuracy between the extraoral scanners (p=0.0806). However, when analyzing only the components, component D was more accurate when scanned with Ceramill Map400+ compared with AutoScan DS200+ (p<0.001) and with E2 (p=0.002). Conclusions: All extraoral systems assessed showed digitalization accuracy but with more deviations in angled implants. The Ceramill Map400+ scanner showed the best results for the digital impression of a complete arch

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PURPOSE: To evaluate and compare the effect of impression type (conventional vs digital) and the number of implants on the time from the impressions to the generation of working casts of mandibular implant-supported fixed complete-arch frameworks, as well as on patient satisfaction. MATERIALS AND METHODS: 17 participants, 3 or 4 implants, received 2 types of digital impression methods (DI) and conventional (CI). In DI, two techniques were performed: scanning with the scan bodies (SC) and scanning with a device attached to the scan bodies (SD) (BR 10 2019 026265 6). In CI, the making of a solid index (SI) and open-tray impression (OT) were used. The outcomes were used to evaluate the time and the participant satisfaction with conventional and digital impressions. The time was evaluated through the timing of the time obtained in the workflow in the conventional and digital impression. The effect of the number of implants on time was also assessed. Satisfaction was assessed through a questionnaire based on seven. The Wilcoxon test used to identify the statistical difference between the groups in terms of time. The Mann-Whitney test was used to analyze the relationship between the time and the number of implants. Fisher's test was used to assess the patient satisfaction (P < .05). RESULTS: The time with DI was shorter than with CI (DI, x̃=02:58; CI, x̃=31:48) (P < .0001). The arches rehabilitated with 3 implants required shorter digital impression time (3: x̃=05:36; 4: x̃=09:16) (P < .0001). Regarding satisfaction, the DI was more comfortable and pain-free than the CI (P < .005). CONCLUSION: Digital impressions required shorter chair time and had higher patient acceptance than conventional impressions.

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Objective: to evaluate the impact of three different scan strategies and implant angulation on impression accuracy of an intraoral scanner for full-arch multiple implant scan. Material and Method: A maxillary edentulous model with six implant analogs served as a reference model. The four anterior analogs were positioned parallel to each other, the distal right and the distal left was placed with an angulation of 15o and 20o, respectively. Thirty impression were performed using an intraoral scanner (CEREC Primescan). The master cast was digitalized with an industrial reference scanner (ATOS Core 80). All scans were converted to standard tessellation language (STL), superimposed on the reference scan with a 3d inspection software (GOM Inspect Professional 2019) and then analyzed. Results: All linear distances presented equivalence [p<0.01] to those found on the reference scan for all scan strategies. All scan strategies presented a tendency of negative means for linear distances except for d4 in strategy C. All angular distances did not present equivalence [p=0.05] to those found on the reference scan. Significant 3D deviations [p<0.05] were found between strategy B (0.02 ± 0.01) and C (0.05 ± 0.04) for d1. In all others linear and angular distances no statistically significant difference was found between strategies A, B and C. Conclusions: There was no statistically significant difference between strategies A, B and C except for d1 in strategy B and C; Implant angulation did not affect the accuracy of the CEREC Primescan IOS (AU)

Objetivo: avaliar o impacto de três diferentes estratégias de escaneamento e angulação do implante na acurácia da moldagem de um scanner intraoral na moldagem de múltiplos implantes em arco completo. Material e Métodos: Um modelo edêntulo de maxila contendo seis análogos de implante serviu como modelo de referência. Os quatro análogos anteriores foram posicionados paralelos entre si, o distal direito e o distal esquerdo foram posicionados com angulação de 15o e 20o, respectivamente. Trinta moldagens foram realizadas usando um scanner intraoral (CEREC Primescan). O modelo mestre foi digitalizado com um scanner de referência industrial (ATOS Core 80). Todas as escaneamentos foram convertidas para a linguagem de mosaico padrão (STL), sobrepostas ao escaneamento de referência com um software de inspeção 3D (GOM Inspect Professional 2019) e, em seguida, analisadas. Resultados: Todas as distâncias lineares apresentaram equivalência [p <0,01] àquelas encontradas na escaneamento de referência para todas as estratégias. Todas as estratégias de escaneamento apresentaram tendência de médias negativas para distâncias lineares, exceto para d4 na estratégia C. Todas as distâncias angulares não apresentaram equivalência [p = 0,05] às encontradas no escaneamento de referência. Desvios 3D significativos [p <0,05] foram encontrados entre a estratégia B (0,02 ± 0,01) e C (0,05 ± 0,04) para d1. Em todas as outras distâncias lineares e angulares, nenhuma diferença estatisticamente significativa foi encontrada entre as estratégias A, B e C. Conclusões: Não houve diferença estatisticamente significante entre as estratégias A, B e C, exceto para d1 na estratégia B e C; A angulação do implante não afetou a precisão do CEREC Primescan. (AU)

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Abstract Introduction: Inspite of the great advances in dentistry, aging populations imply that there are still significant numbers of edentulous people worldwide. In most cases, implant-assisted prosthetic rehabilitation is the best solution. However, economic issues constrain access to this therapeutic approach, meaning that conventional removable prosthetics continue to be the most frequent treatment. In the removable denture making process, the so-called traditional method has been widely taught and used. It involves taking two impressions: a preliminary one followed by a definitive one (or functional). The simplified method constructs the prosthesis directly from the first impression obtained with a stock tray, without the need of a second impression. Purpose: To review the scientific evidence comparing both methods in terms of patient satisfaction, clinical quality, and masticatory performance and capacity. Results: No advantages have been found in favor of the traditional method regarding the four variables selected. Conclusions: According to the available information, the traditional method of taking impressions for complete removable dental prostheses does not provide significantly superior clinical results when compared to those obtained using the simplified method in terms of clinical quality, patient satisfaction, performance and masticatory capacity.

Resumen Introducción: Pese a los avances de la odontología, el fenómeno del envejecimiento de la población ha generado que la cantidad de personas desdentadas totales aún represente una cifra significativa. Los artificios protésicos implanto-asistidos constituyen, en la mayoría de los casos, la mejor alternativa rehabilitadora. Sin embargo, la variable económica surge como el principal impedimento para que los pacientes accedan a este recurso, y por este motivo, mantienen la prótesis total removible como una opción terapéutica. Para su confección, el método tradicional indica la necesidad de tomar dos impresiones: una preliminar y una definitiva o funcional. El método simplificado, confecciona la prótesis a partir de la primera impresión, obtenida con cubeta de stock. Objetivo: Revisar evidencia científica que compara ambos métodos en cuanto a las variables de: satisfacción del paciente, calidad clínica, rendimiento y capacidad masticatoria. Resultados: No se verifican ventajas a favor del método tradicional en relación a las variables estudiadas. Conclusiones: En concordancia con la información recabada, los resultados clínicos obtenidos mediante el método tradicional de toma de impresiones para prótesis totales no son significativamente superiores a los del método simplificado en relación a calidad clínica, satisfacción del paciente, rendimiento y capacidad masticatoria.

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ABSTRACT Introduction: The passivity of prosthetic components is one of the most important prerequisites in oral implant rehabilitation for maintenance of osseointegration. Objective: Thus, the present study analyzed in vitro the accuracy of different molding techniques in prosthetic rehabilitation on angled implants installed in an anatomical model of a metallic edentulous maxilla. Methods: Laboratory experiment study. A reference metal model of an edentulous maxilla was used. A metal framework was used for the misadaptation assessment. Three groups (n= 10) were compared and impressions were made with vinyl-polysiloxane and casts were obtained with type IV stone: (1) Impression with a metallic open-tray without splinted transfers; (2) Impression with a metallic open-tray and metal splinted transfers; (3) Impression with a multifunctional guide and metal splinted transfers. Misadaptation was assessed with the aid of a stereomicroscope and measuring software. Data were submitted to ANOVA with Welch correction and the Games-Howell post-hoc test with the significance set at 5 percent. Results: Misadaptation (µm) was 110,23 ± 30,94, 37,53 ± 3,92, and 37,69 ± 2,79 for the the groups. Statistically significant differences between impression with a metallic open-tray with and without splinted transfers were observed (p < 0,001). No significant differences between the other types of impression. Conclusions: Impression with a metallic open-tray without splinted transfers and with a multifunctional guide splinted with metal transfers were the most precise methods resulting in higher accuracy in transferred implants(AU)

RESUMEN Introducción: La pasividad de los componentes protésicos es uno de los prerrequisitos más importantes para el mantenimiento de la osteointegración en la rehabilitación oral sobre implantes. Objetivo: Evaluar in vitro la precisión de diferentes técnicas de impresión en rehabilitación sobre implantes inclinados instalados en un modelo anatómico de un maxilar metálico desdentado. Métodos: Estudio de laboratorio de tipo experimental. Se utilizó un modelo metálico de referencia de un maxilar desdentado. Fue utilizada una barra metálica para la evaluación de la desadaptación. Se compararon tres grupos (n = 10), se realizaron impresiones con polivinilsiloxano y se obtuvieron modelos con yeso piedra tipo IV: (1) impresión con una cubeta metálica abierta sin unión de los transferentes; (2) impresión con una cubeta metálica abierta y unión de los transferentes con cilindros metálicos; (3) impresión con una guía multifuncional y unión de los transferentes con cilindros metálicos. La desadaptación se evaluó con la ayuda de un microscopio estereoscópico y un software de medición. Los datos se enviaron a ANOVA con la corrección de Welch y la prueba post-hoc de Games-Howell con la significación establecida en 5 por ciento. Resultados: La desadaptación (µm) fue de 110,23 ± 30,94; 37,53 ± 3,92 y 37,69 ± 2,79 para los grupos, respectivamente. Se observaron diferencias estadísticamente significativas entre la impresión con cubeta abierta metálica con y sin unión de los transferentes (p <0,001). No hubo diferencias significativas entre los otros tipos de impresiones. Conclusiones: La impresión con cubeta abierta metálica sin unión de los transferentes y con una guía multifuncional con unión de los transferentes con cilindros metálicos fueron los métodos más precisos que dieron como resultado una mayor precisión en la transferencia de la posición de los implantes(AU)

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RESUMO Introdução: O escâner intraoral é um aparelho que surge como alternativa aos métodos convencionais de moldagem utilizando a técnica de impressão digital. O meio acadêmico vem realizando diversos estudos para avaliar a real efetividade da tecnologia e sua aplicabilidade clínica. Objetivo: Analisar resultados obtidos em estudos sobre escâneres intraorais na área de implantodontia quanto ao tipo de escâneres e acurácia, tempo de trabalho e preferência do operador e do paciente. Métodos: Foram realizadas buscas de artigos nas bases de dados "Pubmed" e "SciELO" utilizando os seguintes descritores: «intraoral AND scanner AND implant¼, «digital AND scanner AND implant¼ e «digital AND impression AND implant¼ em inglês, português e espanhol respectivamente. Os critérios de inclusão foram: artigos de avaliação clínica (in vivo) ou laboratorial (in vitro) que avaliassem o uso da técnica de escaneamento intra-oral para impressão digital de implantes com acesso integral, escritos em português, inglês ou espanhol e publicados a partir de 2013. Análise e integração da informação: Foram encontrados 158 artigos. Após a análise e seleção, 35 artigos foram incluídos, sendo 28 laboratoriais e 7 clínicos. Apesar de limitações na padronização dos estudos, percebemos o potencial e a viabilidade da técnica digital, com resultados clínicos e de acurácia favoráveis e vantagens como redução do tempo e etapas de trabalho, comunicação dinâmica com os laboratórios, preferência de pacientes e estudantes de odontologia e facilidade de incorporação por profissionais já experientes. Conclusões: Estudos laboratoriais indicam que, além de vantagens quanto ao uso de materiais de moldagem, comunicação com os laboratórios e facilidade de manipulação, a técnica digital pode alcançar resultados superiores aos da técnica convencional, assim, a técnica se mostra promissora para a área de implantodontia sendo necessário, contudo, estudos futuros, especialmente in vivo, para avaliar a consistência dos resultados clínicos(AU)

RESUMEN Introducción: El escáner intrabucal es un aparato que surge como una alternativa frente a los métodos convencionales de moldeo, y el medio académico viene realizando diversos estudios para evaluar la real efectividad de esta tecnología y su aplicabilidad clínica. Objetivo: Analizar resultados obtenidos en estudios sobre escáneres intrabucales en el área de implantología en cuanto a los tipos de escáneres y la exactitud, tiempo de trabajo y preferencia del operador y del paciente. Métodos: Se realizaron búsquedas en las bases de datos "PubMed" y "SciELO" utilizando los siguientes descriptores: "intraoral AND scanner AND implant", "digital AND scanner AND implant" and "digital AND impression AND implant" en inglés, portugués y español, respectivamente. Los criterios de inclusión fueron: artículos clínicos o de laboratorio para evaluar el uso de la técnica de escaneamiento digital de los implantes, con acceso completo al artículo, escrito en portugués, inglés o español y publicados desde 2013. Análisis e integración de la información: Se encontraron 158 artículos. Después del análisis y selección, 35 artículos fueron incluidos, siendo 28 de laboratorio y 7 clínicos. A pesar de las limitaciones en la estandarización de los estudios, percibimos el potencial y la viabilidad de la técnica digital, con resultados clínicos y de precisión favorables y ventajas como reducción del tiempo y etapas de trabajo, comunicación dinámica con los laboratorios, preferencia de pacientes y estudiantes de odontología y facilidad de incorporación de profesionales experimentados. Conclusiones: Los estudios de laboratorio indican que, además de ventajas en cuanto al uso de materiales de moldeo, comunicación con los laboratorios y facilidad de manipulación, la técnica digital puede alcanzar resultados superiores a los de la técnica convencional, por lo que el uso de escáneres intrabucales se muestra prometedor para el área de implantología siendo necesario, sin embargo, estudios futuros, especialmente in vivo, para evaluar la consistencia de los resultados clínicos(AU)

ABSTRACT Introduction: Intraoral scanners are devices that emerged as an alternative to conventional impression methods. A variety of studies have been conducted to evaluate the actual effectiveness of this technology and its clinical applicability. Objective: Analyze the results obtained by studies about intraoral scanners in the area of implantology in terms of types, accuracy, working time, and operator and patient preference. Methods: A search was conducted in the databases PubMed and SciELO using the following descriptors: "intraoral AND scanner AND implant", "digital AND scanner AND implant" and "digital AND impression AND implant" in English, Portuguese and Spanish. The inclusion criteria were the following: clinical or laboratory papers evaluating the use of digital implant scanning technique, full access to the paper, written in Portuguese, English or Spanish and published as of the year 2013. Data analysis and integration: Of the 158 papers obtained and analyzed, 35 were selected: 28 laboratory and 7 clinical. Despite the limitations in the standardization of the studies, we perceive the potential and viability of the digital technique, with favorable clinical and accuracy results, as well as advantages such as a reduction in work time and stages, dynamic communication with laboratories, preference by patients and dental students and ease of technical incorporation by experienced dentists. Conclusions: Laboratory studies indicate that, in addition to the advantages concerning the use of impression materials, communication with laboratories and ease of manipulation, the digital technique may achieve better results than conventional impression techniques. The use of intraoral scanners is therefore a promising technique for the area of ​​implantology. However, further studies shouldbe conducted, especially in vivo, to evaluate the consistency of the clinical results obtained(AU)

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OBJECTIVES: To evaluate the effectiveness of CCDs produced by two impression procedures for the mandibular ridge, in patients with severe mandibular atrophy. METHODS: Fifty-two completely edentulous patients with severely resorbed mandibles were randomly allocated into two groups according to the impression procedure of the mandibular ridge: SI - single impression (stock tray and irreversible hydrocolloid); TI - two-step impression (custom tray, border molding with compound, and polyether). Assessments of oral health related quality of life (OHRQoL, primary outcome) and denture satisfaction were performed by using validated questionnaires. Denture quality was evaluated by means of functional tests. RESULTS: Regardless of the technique, participants reported better OHRQoL (P < 0.001) in both follow-up periods (3 and 6 months after denture delivery), and groups resulted in similar OHIP-EDENT scores in its different domains (P > 0.05). Between-group differences were insignificant for general satisfaction (3 months, P = 0.699, 6 months, P = 0.392), as well as for aspects such as esthetics, comfort, mastication, speech, and prosthesis retention (P > 0.05). Overall clinical quality of the CCDs (P = 0.383) was similar between-group, as well as in specific aspects - interocclusal distance, occlusion, articulation, retention of the maxillary denture, and stability of both maxillary and mandibular dentures (P > 0.05). CONCLUSIONS: Mandibular CCDs based on a single impression technique showed quality levels comparable to those generated by a two-step impression, both from the patient and clinician perspective. CLINICAL SIGNIFICANCE: A simplified impression technique which eliminates the secondary impression can provide CCDs of good clinical quality, which influences the OHRQoL, and satisfaction in the same extent they would by a two-step procedure, even for patients with severely reabsorbed mandibular ridges. (ClinicalTrials.gov: NCT02339194).

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OBJECTIVES: To compare one- vs two-step impression procedures for the provision of conventional complete dentures (CCDs) for edentulous individuals with severe mandibular resorption, in terms of (1) masticatory performance and ability; (2) satisfaction with mandibular CCDs; and (3) post-delivery adjustments. METHODS: Fifty-two patients requiring maxillary + mandibular CCDs were randomly divided into two parallel arms according to the impression method of the mandibular ridge: (SI) single impression with stock trays (irreversible hydrocolloid); (TI) two-step impression in custom trays, with border molding (impression compound) followed by the impression itself (polyether). Mastication performance was evaluated by a colorimetric test, whereas patients answered questions on masticatory ability and satisfaction with mandibular CCDs (100-mm visual analogue scale). The number of post-delivery sessions for adjustments were also quantified. Outcomes were assessed at 3 and 6 months after delivery. RESULTS: The masticatory performance was similar for both groups, regardless of time (3 months, P = 0.62; 6 months, P = 0.61). No significant difference was found for patient-reported (P > 0.05), i.e. masticatory ability (general ease of chewing and quality of grinding food; ability to chew specific foods), general satisfaction with the mandibular CCD (general satisfaction, comfort, aesthetics, ability to speak and to perform correct cleaning, retention and stability). Both methods resulted in a similar number of post-delivery adjustment sessions [SI: 3.8 (1.7); TI: 3.2 (1.4); P = 0.09]. CONCLUSIONS: Compared to a traditional approach, CCDs obtained from a single impression achieve similar masticatory performance/ability and patient satisfaction, even in patients with severely reabsorbed mandibular ridge. Both methods demand the same amount of post-delivery adjustment. CLINICAL SIGNIFICANCE: A simplified impression technique which eliminates the secondary impression can provide CCDs of good clinical quality, which influences the OHRQoL, and satisfaction in the same extent they would by a two-step procedure, even for patients with severely reabsorbed mandibular ridges (ClinicalTrials.gov: NCT02339194).

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Aim: To compare the accuracy (trueness and precision) of cost-accessible three-dimensional (3D) printed models. Methods: A maxillary typodont (MM) was scanned and printed 10 times in polylactic acid, resulting in 10 digital models (DMs). Polyvinylsiloxane impressions were made to obtain 10 conventional stone models (SMs). All models were scanned and imported to CloudCompare software. The total area and three locations of interest were evaluated (zenith to incisal [Z-I], canine to canine [C-C], and first molar to canine [1M-C] distances). Total area evaluations were performed by aligning the MM and experimental models using the best-fit algorithm and were compared using the Haussdorf distance. The distances between points of interest were measured using the point-picking tool at the same 3D coordinates. The mean volumetric deviations were considered for trueness analysis. Precision was set as the standard deviation. Statistical differences were evaluated using the Student's t-test. Results:Total area volumetric comparisons showed that DMs showed superior trueness and precision (-0.02 ± 0.03) compared to the SMs (0.37 ± 0.29) (P < 0.001). No differences between the models were observed for Z-I (P = .155); however, SMs showed fewer deviations for C-C (P = .035) and 1M-C (P = .001) than DMs. Conclusions: The DMs presented superior trueness and precision for total area compared to the SMs; however, the SMs were more accurate when points of interest were evaluated

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Objetivo: Comparar diferentes técnicas de moldagem com silicone de adição, quanto à precisão e fidelidade da cópia através de medidas manuais e sobreposição em CAD/CAM. Material e método: Foram realizadas 4 moldagens com silicone de adição de um mesmo modelo nas seguintes técnicas: T1 ­ dois passos com recorte; T2 ­ dois passos com alívio de filme PVC; T3 ­ dois passos sem alívio e T4 - simultânea. A fidelidade das 4 técnicas de moldagem foi avaliada por meio de mensurações de 5 dimensões nos modelos de gesso vazados em cada um dos moldes obtidos. Outra forma de análise foi a sobreposição de imagens no CAD/CAM, com a finalidade de verificar se há semelhanças ou diferenças dimensionais entre o modelo piloto e as amostras. As medidas obtidas foram submetidas ao teste ANOVA com comparações múltiplas pelo teste de Tukey (α=0,05). Resultados: De acordo com as mensurações, a técnica que apresentou maior discordância do modelo piloto foi a T4, não havendo diferença entre as outras técnicas. Na avaliação em CAD/CAM, as técnicas T4 e T3 apresentaram maiores diferenças em relação ao modelo original de acordo com as imagens sobrepostas. Conclusões: Todas as técnicas estudadas apresentaram alterações dimensionais, em especial a técnica simultânea e a sem alívio, tanto nas medidas obtidas quanto na análise em CAD/CAM.

Objetives: To compare different impression techniques with addition silicone, by means of copy accuracy through manual measurements and overlaping in CAD/CAM. Material and methods: Four impressions of a same pilot model were carried out with silicone addition in different techniques: T1 ­ two steps with cut-back; T2 ­ two steps with PVC film relief; T3 ­ two steps without relief; and T4 ­ one step. The accuracy of the 4 different impression techniques was assessed by measuring 5 dimensions on stone casts poured from the impressions of the pilot model. Another analysis was carried out in CAD/CAM using the overlaping of the casts and the pilot model, in order to verify dimensional similarities and differences between them. The values obtained were submitted to ANOVA and Tukey test, for multiple comparisons (α=0.05). Results: According to the measures done, the technique that generated the greatest difference from the pilot model was T4, with no difference among the other techniques. In CAD/CAM analysis, techniques T4 and T3 presented more differences from the original model. Conclusions: All studied techniques presented dimensional changes, mainly the 1 step and the 2 step without relief, in both methods, measures and CAD/CAM analysis.

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The purpose of this article was to present an alternative procedure using resin-based provisional material to create the posterior palatal seal (PPS). This method offers more practicality in clinical routine and increased control for addition of material to create the PPS when compared to traditional techniques such as the use of impression wax.

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Aim: This study compared impression techniques and double pouring by means of cast's accuracy. Methods: For each patient (n=10), impressions from right maxillary canine to first molar were made with acrylic resin trays and vinyl-polysiloxane using one single-step, and four two-steps techniques: relief with poly(vinyl chloride) film; tungsten-carbide bur/scalpel blade; small movements of the tray; non-relief. Total visible buccal surface area of crowns was measured three times using photographs from patients (Baseline) and casts. Mean area values (mm2) between Baseline and casts differences were analyzed by two-way repeated-measures ANOVA (α=.05; 1-ß=85%). Results: No significant differences were observed for Impression Techniques (P=.525), Double Pouring (P=.281), and their interaction (P=.809). Conclusion: All impression techniques and double pouring produced casts with similar accuracy

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Abstract Introduction Making accurate and dimensionally stable impressions to duplicate oral conditions and tooth morphology is an essential step of prosthetic dentistry for fabricating well-fitted indirect restorations and, consequently, ensure the longevity and success of the treatment. Several authors describe pros and cons of different impression techniques, although there is no unanimity among them about the best one. Objective This study evaluated casts' accuracy made by different impression techniques, trays and materials. Material and method 10 patients were selected and 20 impressions from teeth #13 to #16 were performed using single-step (SS) and two-step techniques, made with metal stock and customized acrylic resin partial trays, vinyl polysiloxane and condensation silicone rubbers. Type IV gypsum was used to pour the casts. Three photographs of each patient (baseline), as their respective gypsum casts, were taken, measured in their interested buccal surface area. Comparisons of area values among experimental groups and baseline were performed. Data showed adherence to normal curve, being submitted to 3-way ANOVA/Bonferroni test (α=.05). Result Technique produced significant differences (P=0.02). SS technique was more accurate than BUR one (P=0.003; 95=1.22 to 5.98), but both resulted in similar casts to PVC, MOV and NR techniques, which were similar to each other (P>0.05). Conclusion SS technique showed the closest absolute values to baseline.

Resumo Introdução Realizar moldagens precisas e dimensionalmente estáveis que dupliquem a condição oral é um passo essencial para a confecção de restaurações indiretas de qualidade, garantindo seu sucesso e longevidade. Diversos estudos tem demonstrado os prós e contras de diferentes técnicas de moldagem, mas nenhum consenso da melhor técnica ainda foi descrito. Objetivo Este estudo avaliou a exatidão de modelos de gesso confeccionados por diferentes técnicas de moldagem, moldeiras e materiais. Material e método 10 pacientes foram selecionados e 20 moldes dos dentes #13 até #16 foram realizados utilizando técnicas simultânea (SS) e de dois passos, realizados com moldeiras parciais metálicas e individuais de resina acrílica, silicones de adição e condensação. Gesso tipo IV foi usados para os vazamentos. Três fotografias de cada paciente (baseline), assim como dos seus respectivos modelos de gesso foram realizadas e sua área foi então mensurada, na porção vestibular. Comparações de valores de área entre os grupos experimentais e o baseline foram performadas. Os dados mostraram aderência a curva normal, sendo submetidos ao teste 3-way ANOVA/Bonferroni (α=.05). Resultado As técnicas produziram diferenças significativas (P=0.02).Técnica simultânea foi mais precisa que a BUR (P=0.0003; 95=1,22 a 5.98), mas ambas resultaram em modelos similares àqueles feitos por meio das técnicas de PVC, MOV e sem NR, que foram similares entre si (P>0.05). Conclusão Técnica simultânea demonstrou valores absolutos similares àqueles demonstrados pelo baseline.

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Objetivo: El propósito de este estudio fue evaluar el uso de un jig de verificación para corregir la posición de los implantes dentales en un modelo impreso en 3D y comparar su precisión con los modelos dentales obte-nidos por impresión convencional. Materiales y Métodos: Se instalaron tres implantes dentales en un modelo maxilar dentado parcial y se obtuvieron moldes dentales (n = 10) mediante impresiones convencionales y digi-tales. Se usó una plantilla de verificación para determinar la posición del implante en el modelo impreso en 3D y su precisión se comparó con el molde convencional. Resultados: Los datos se analizaron mediante ANOVA y prueba post hoc a un nivel de significancia de p ≤ 0.05. Se encontró un error de medición estadísticamente mayor (p≤ 0.05) para los modelos impresos en 3D en comparación con los modelos convencionales, con una diferencia media de 47 µm. Conclusión: El uso de un jig de verificación para colocar implantes dentales en un modelo impreso en 3D mostró mayores discrepancias en comparación con las impresiones convencionales.

Objective: The purpose of this study was to assess the use of a verification jig to correct the position of den-tal implants in a 3D printed model and to compare its accuracy with dental casts obtained by conventional impression. Materials and Methods: Three dental implants were installed in a partial dentate maxillary model and dental casts (n=10) were obtained by conventional and digital impressions. A verification jig was used to determine the implant position into the 3D printed model and its accuracy was compared with conventional cast. Results: Data were analyzed by within ANOVA and post hoc test at a significance level of p ≤ 0.05. A statistically higher measurement error (p≤ 0.05) was found for 3D printed models in comparison with conven-tional models, with a mean difference of 47µm. Conclusion: The use of verification jig for positioning dental implants in a 3D printed model

Objetivo: O objetivo deste estudo foi avaliar o uso de um jig de verificação para corrigir a posição dos implan-tes dentários em um modelo impresso em 3D, e comparar sua precisão com os modelos dentários obtidos pela impressão convencional. Materiais e Métodos: Três implantes dentários foram instalados em um modelo maxilar parcialmente dentado e os moldes dentários (n = 10) foram obtidos por impressões convencionais e digitais. Um modelo de verificação foi usado para determinar a posição do implante no modelo impresso em 3D e sua precisão foi comparada com o molde convencional. Resultados: Os dados foram analisados por ANOVA e teste post hoc com nível de significância de p ≤ 0,05. Foi encontrado um erro de medição estatistica-mente maior (p≤ 0,05) para os modelos impressos em 3D em comparação aos modelos convencionais, com uma diferença média de 47 µm. Conclusão: O uso de um jig de verificação para colocação de implantes dentários em um modelo impresso em 3D mostrou maiores discrepâncias em relação às impressões conven-cionais.

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Abstract Objective: To analyze the efficacy of retraction cord with a hemostatic agent in comparison with retraction paste on lateral gingival displacement, to achieve the success of fixed dental prostheses (FDP). Material and Methods: Test samples included 32 teeth that required treatment with metal-porcelain FDP at RSKGM FKG Universitas Indonesia. Impressions were taken before the gingival retraction procedure. From the 32 samples, 16 teeth were retracted using a combination of retraction cord and hemostatic agent, whereas the other half were retracted with retraction paste. Impressions were then taken. The sample was made using cutting die. Lateral gingival displacement width was measured on die-cast using an optical microscope Results: The mean value of group A before gingival retraction was 0.1695 mm, and after gingival retraction was 0.4705 mm. The mean value of group B before gingival retraction was 0.1767 mm, and after gingival retraction was 0.3289 mm. Lateral gingival displacement width between a combination of cord retraction and hemostatic agent group in comparison with the retraction paste group showed a significant difference (p<0.001). The combination of cord retraction and hemostatic agent group showed higher mean value Conclusion: Gingival displacement width as a result of cord retraction with the hemostatic agent was larger compared to the retraction paste. Even though both of them are still considered to be effective in providing access for impression material.

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ABSTRACT: The aim of this study was to carry out a literature review on the accuracy of conventional and digital dental impression methods, as well as present the various three-dimensional intraoral scanning systems. A bibliographic search was carried out in PUBMED's main health database, in which works published between 2008 and 2018 were collected. Laboratory studies, case reports and systematic reviews were included, addressing topics that deal with conventional digital materials, impression and precision. Articles that did not evaluate impression materials, their behavior and techniques to obtain a good impression of oral structures were excluded. Through a review in the literature, obtained the following findings: the most critical stage in macking a dental prothesis is to take the dental impression. The conventional technique of impression consists of obtaining a negative copy of the intra-oral situation that will be poured into gypsum, obtaining a positive copy, on which the work will be carried out. Digital scanning systems were not superior to conventional moldings when comparing fidelity, accuracy and detail reproduction; in contrast, they were superior to conventional impression when considering clinical chair time, patient and operator preference, and patient comfort.

RESUMEN: El objetivo de este estudio consistió en realizar una revisión bibliográfica sobre la precisión de los métodos de moldeo dental convencionales y digitales, así como presentar los diversos sistemas de escaneo intraoral tridimensionales. Se realizó una búsqueda bibliográfica en la base de datos de salud principal de PUBMED en la cual se recopilaron trabajos publicados entre 2008 y 2018. Se incluyeron estudios de laboratorio, informes de casos y revisiones sistemáticas, abordando temas que tratan con materiales digitales convencionales, moldeo y precisión. Se excluyeron los artículos que no evaluaron los materiales de moldeo, su comportamiento y técnicas para obtener una buena impresión de las estructuras orales. A través de una revisión exhaustiva en la literatura, obtuvimos los siguientes hallazgos: el paso más crítico en la preparación de una pieza protésica es la impresión de la preparación. La técnica convencional de moldeo consiste en obtener una copia negativa de la situación intraoral que se verterá en el yeso, obteniendo una copia positiva, sobre la cual se realizará el trabajo. Resulta que los sistemas de escaneo digital no fueron superiores a las molduras convencionales al comparar la fidelidad, precisión y reproducción de detalles; en cambio, fueron superiores a las molduras convencionales al considerar el tiempo de trabajo clínico, la preferencia del paciente y del operador y la comodidad del paciente.

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