Digital repair for a patient with limited mouth opening: a case report and literature review / 口腔疾病防治

Objective@#To explore an accurate method to obtain an intraoral model of patients with specific limited mouth opening (microstomia) due to systemic scleroderma.@*Methods@#This study followed medical ethics, and informed consent has been obtained from patients. A case of Ken's Type I mandibular dentition defect scleroderma with limited mouth opening was addressed with digital technology as the leading method combined with the traditional impression method of segmental impression. Individual trays were made based on the patient's left and right mandibular dentition, and segmented molds were obtained. Simultaneously, intraoral scanning was performed to obtain the morphological data of both the soft and hard tissues of the upper and lower mandibles. After each part of the model was obtained, the mandibular model was scanned and digitally aligned to form the final denture model, and the final removable partial denture was designed and made by computer aided design/computer aided manufacturing (CAD/CAM) technology. At the same time, combined with the literature, the diagnosis and treatment of removable partial denture in patients with limited mouth opening were retrospectively analyzed.@*Results@#The denture was well retained and achieved a good repair effect. The patients expressed satisfaction with the mastication efficiency and other functions of the denture. The findings of the literature review show that the integration of digital technology with the traditional impression method, along with computer fitting, can accurately obtain the patient's oral model and facilitate successful follow-up repairs. However, when the anterior mandibular dentition of the patient is absent, the margin of error is increased in this procedure, which deserves further exploration.@*Conclusion@#Utilizing digital technology as the leading method, combined with the traditional impression method of segmental impression, for the repair of dental defects in patients with limited mouth opening, has proven to be effective. Thus, patients report a positive medical experience with high satisfaction, indicating that this approach is worthy of clinical promotion.

Estabilidad dimensional de hidrocoloides irreversibles de vaciado convencional y de vaciado de tiempo extendido disponibles en el mercado uruguayo

Objetivo. Comparar la estabilidad dimensional de un hidrocoloide irreversible de vaciado convencional con hidrocoloides irreversibles de vaciado extendido. Metodología. Fueron evaluados cuatro productos con indicación de vaciado extendido: Jeltrate Plus (Denstply Sirona), Hydrogum 5 (Zhermack SpA), Algimax (Major), Kromopan (Lascod) y un producto de vaciado convencional (Tropicalgin; Zhermack SpA). Con cada producto se realizaron 10 impresiones y se vaciaron en yeso tipo III en cinco tiempos de almacenamiento diferentes (0, 24, 96, 120 y 168 horas). Un escáner para modelos tridimensionales se utilizó para digitalizar los modelos de yeso y realizar las mediciones correspondientes: sumatoria de las longitudes, variabilidad dimensional, porcentaje de variabilidad. Resultados. Las cinco marcas comerciales presentaron una sumatoria de longitudes mayor al grupo control (p<0,033). A las 0, 24 y 96h Tropicalgin e Hydrogum 5 presentaron significativamente menor variación dimensional en comparación con el modelo maestro (p<0,001). Los porcentajes de variabilidad oscilaron entre un 0.24 a 0.91%. Conclusiones. La estabilidad dimensional depende del producto utilizado. Almacenado correctamente, el hidrocoloide irreversible de vaciado convencional parece no sufrir alteraciones significativas hasta 96h, mientras que en el caso de Hydrogum 5 parece mantener su estabilidad dimensional hasta 168h.

Objetivo. Comparar a estabilidade dimensional de um hidrocolóide irreversível de vazamento convencional com hidrocolóides irreversíveis de vazamento prolongado. Metodologia. Foram avaliados quatro produtos com indicação de vazamento estendido: Jeltrate Plus (Denstply Sirona), Hydrogum 5 (Zhermack SpA), Algimax (Major), Kromopan (Lascod) e um produto de vaziamento convencional (Tropicalgin; Zhermack SpA). Para cada produto foram feitas 10 impressões e vazadas em gesso tipo III em cinco tempos de armazenamento diferentes (0, 24, 96, 120 e 168 horas). Um scanner de modelos tridimensionais foi utilizado para digitalizar os modelos de gesso e fazer as medições correspondentes: soma dos comprimentos, variabilidade dimensional, percentagem de variabilidade. Resultados. As cinco marcas comerciais apresentaram somatório de comprimentos maior que o grupo controle (p<0,033). Nos tempos 0, 24 e 96h Tropicalgin e Hydrogum 5 apresentaram variação dimensional significativamente menor em comparação ao modelo Mestre (p<0,001). Os percentuais de variabilidade variaram de 0,24 a 0,91%. Conclusões. A estabilidade dimensional depende do produto utilizado. Armazenado corretamente, o hidrocolóide irreversível de vaziamento convencional convencionalmente parece não sofrer alterações significativas até 96h, enquanto no caso do Hydrogum 5 parece manter sua estabilidade dimensional até 168h.

Aim . Compare the dimensional stability of a conventional pouring irreversible hydrocolloid with extended pouring irreversible hydrocolloids. Methodology. Four products with extended emptying indication were evaluated: Jeltrate Plus (Denstply Sirona), Hydrogum 5 (Zhermack SpA), Algimax (Major), Kromopan (Lascod) and a conventional emptying product (Tropicalgin; Zhermack SpA). For each product, 10 impressions were made and cast in type III plaster at five different storage times (0, 24, 96, 120 and 168 hours). A three-dimensional model scanner was used to digitize the plaster models and make the corresponding measurements: sum of lengths, dimensional variability, percentage of variability. Results . The five commercial brands presented a greater sum of lengths than the control group (p<0,033). At 0, 24 and 96h Tropicalgin and Hydrogum 5 presented significantly less dimensional variation compared to the master model (p<0,001). The variability percentages ranged from 0.24 to 0.91%. Conclusions. Dimensional stability depends on the product used. Stored correctly, the conventionally cast irreversible hydrocolloid appears not to undergo significant alterations up to 96h, while in the case of Hydrogum 5 it appears to maintain its dimensional stability up to 168h.

Implant digital impression accuracy using extraoral scanners: a three-dimensional analysis

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

Application of polyetheretherketone (PEEK) posts: evaluation of fracture resistance and stress distribution in the root: in vitro and finite element analyses

Abstract To evaluate the feasibility of using a milled polyetheretherketone (PEEK) post and core in endodontically treated teeth with or without a ferrule. Sixty bovine tooth roots were endodontically treated followed by cementation of intraradicular retainers (IR), according to each experimental group: a) non-ferrule glass fiber post (f0FP); b) 2-mm-ferrule glass fiber post (f2FP); c) non-ferrule resized glass fiber post (f0PR); d) 2-mm-ferrule resized glass fiber post (f2PR); e) non-ferrule PEEK post and core (f0PPC); and f) 2-mm-ferrule PEEK post and core (f2PPC). Metal crowns were made and cemented. A periodontal ligament was simulated using polyether. A force was applied to the palatine portion of each sample at 45°, until fracture. Fracture resistance data were submitted to two-way ANOVA and Tukey's test (α = 0.05). Three-dimensional digital models were developed to calculate the tensions formed in the root using finite element analysis. Models of glass fiber posts and PEEK posts and cores were evaluated with or without a ferrule. The results were analyzed by the Mohr-Coulomb criterion. The type of IR was not influenced by fracture strength (p = 0.243). There were significant statistical differences among the remaining factors. Ferrule groups had greater fracture resistance, and the failure mode of teeth with a ferrule was more catastrophic than the non-ferrule group. A ferrule increases fracture resistance and influences failure mode; the PEEK post and core did not modify the biomechanics of endodontically treated teeth, and resembled the glass fiber post results. The crack initiation point differed between the ferrule and non-ferrule groups.

Application evaluation of prefabricated rigid connecting bar in implants immediate impression preparation of edentulous jaw / 北京大学学报(医学版)

OBJECTIVE@#To compare the operation complexity and accuracy of traditional splint impression technique and impression technique with prefabricated rigid connecting bar system for full-arch implants-supported fixed protheses in vitro.@*METHODS@#Standard mandibular edentulous model with six implant analogs was prepared. The implants were placed at the bone level and multiunit abutments screwed into the implants. Two impression techniques were performed: the traditional splint impression technique was used in the control group, and the rigid connecting bar system was used in the test group. In the control group, impression copings were screwed into the multiunit abutments and connected with autopolymerizing acrylic resin. Open tray impression was fabricated with custom tray and polyether. In the test group, cylinders were screwed into the multiunit abutments. Prefabricated rigid bars with suitable length were selected and connected to the cylinders with small amount of autopolymerizing acrylic resin, and open tray impression was obtained. Impression procedures were repeated 6 times in each group. The working time of the two impression methods were recorded and compared. Analogs were screws into the impressions and gypsum casts were poured. The gypsum casts and the standard model were transferred to stereolithography (STL) files with model scanner. Comparative analysis of the STL files of the gypsum casts and the standard model was carried out and the root mean square (RMS) error value of the gypsum casts of the control and test groups compared with the standard model was recorded. The trueness of the two impression techniques was compared.@*RESULTS@#The work time in the test group was significantly lower than that in the control group and the difference was statistically significant [(984.5±63.3) s vs. (1 478.3±156.2) s, P < 0.05]. Compared with the standard model, the RMS error value of the implant abutments in the test group was (16.9±5.5) μm. The RMS value in the control group was (20.2±8.0) μm. The difference between the two groups was not significant (P>0.05).@*CONCLUSION@#The prefabricated rigid connecting bar can save the chair-side work time in implants immediate loading of edentulous jaw and simplify the impression process. The impression accuracy is not significantly different from the traditional impression technology. The impression technique with prefabricated rigid connecting bar system is worthy of clinical application.

Impact of different scan strategies and implant angulation on impression accuracy of full arch multiple implant: an in vitro study / Impacto de diferentes estratégias de escaneamento e angulação dos implantes na acurácia da moldagem de implantes múltiplos em arco completo: um estudo in vitro

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)

Traditional versus simplified impression methods for complete dentures: critical appraisal of evidence / Método tradicional versus simplificado en impresiones para prótesis total removible: evaluación crítica de la evidencia Método tradicional versus simplificado

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.

Extended-pour and conventional alginates: effect of storage time on dimensional accuracy and maintenance of details

ABSTRACT Objective: This study aimed to evaluate the dimensional stability and maintenance of details of conventional and high stability alginates up to 5-day storage. Methods: Two types of alginates were selected (n=10) for this study, conventional (Hydrogum) and high stability alginates (Hydrogum 5), which were produced with the aid of a cylindrical metal block and a ring-shaped metal mold (Specifications 18, 19, and 25, ANSI/ADA). Ten images were obtained from the molds for the dimensional stability test, which were taken immediately after their production and at each different storage periods (15 min, 24 h, 48 h, 72 h, 96 h, and 120 h) by a digital camera. The specimens were kept hermetically sealed in plastic bags (23°C) and then used to obtain 140 (n=70) dental stone models, used in the detail reproduction test, in which the angular accuracy of three grooves (20 µm, 50 µm, and 75 µm) was observed at each period. The details reproduction accuracy was classified using a predetermined score classification. Measurements of dimensional changes were made in the Corel DRAW X6 program. The data were submitted to the Student's t-test (α?#8197;= 0.05). Results: A statistically significant difference concerning the size of the matrix was observed after 24h for both alginates, and a statistically significant negative linear dimensional change (contraction) was verified after 24 h of storage (1.52% for the high stability alginate, and 1.32% for the conventional alginate). The high stability alginate kept the full details for 72 hours, while the conventional alginate, for 24 h. Both alginates reproduced the 75 µm groove at all storage periods. Conclusion: Impressions made with both alginates presented satisfactory clinical results when the alginates were immediately poured.

RESUMO Objetivo: O presente estudo teve como objetivo avaliar a estabilidade dimensional e manutenção de detalhes de alginatos convencionais e de alta estabilidade por até 5 dias de armazenamento. Métodos: Para esse estudo, foram selecionados dois tipos de alginatos: convencional (Hydrogum) (n = 10) e de alta estabilidade (Hydrogum 5) (n = 10), sendo produzidos com o auxílio de um bloco metálico cilíndrico e um molde metálico em forma de anel (especificações 18, 19 e 25, ANSI/ADA). Para o teste de estabilidade dimensional, dez imagens foram obtidas imediatamente e para cada tempo de armazenamento (15 min, 24, 48, 72, 96 e 120 horas), realizadas por câmera digital. As amostras foram mantidas hermeticamente fechadas em sacos plásticos (23°C). Para o teste de reprodução de detalhes, as amostras foram utilizadas para obter 140 (n = 70 por grupo) modelos de gesso, sendo observada a precisão angular de três sulcos (20 µm, 50 µm e 75 µm) para cada período. A precisão da reprodução de detalhes foi classificada usando uma classificação de pontuação predeterminada. As medições das mudanças dimensionais foram feitas no programa Corel DRAW X6. Os dados foram submetidos ao teste t de Student (α = 0,05). Resultados: Foi observada diferença estatística em relação à matriz após 24h para ambos os alginatos. Uma mudança dimensional linear negativa estatisticamente significativa (contração) foi verificada após 24 h de armazenamento (1,52% para alginato de alta estabilidade; 1,32% para alginato convencional). O alginato de alta estabilidade manteve os detalhes completos por até 72 horas, enquanto o alginato convencional, por 24 horas. Os alginatos reproduziram o sulco de 75 µm para todos os períodos. Conclusão: As impressões feitas com ambos os alginatos devem ser imediatamente vazadas para se ter resultados clínicos satisfatórios.

Evaluación de la precisión de impresiones sobre implantes usando guía multifuncional en el sistema all-on-four / Accuracy of implant impression using a multifunctional guide in the All-on-Four treatment concept

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)

Dimensional stability of alginate molds scanned at different storage times / Estabilidade dimensional de moldes de alginato digitalizados em diferentes tempos de armazenamento

ABSTRACT The aim of this study was to evaluate the precision and accuracy of molds made with four commercial brands of alginate scanned at different times using digital model analysis. Eighty molds of a standard Typodont were made using 4 types of alginate (CCC: Cavex Color Change; IA: Identic Alginate; HY5: Hydrogum 5 and JP: Jeltrate Plus). The molds were scanned at four times: immediately (T1), 24h (T2), 72h (T3) and 120h (T4) after molding. Measurements were taken in three dimensions: anteroposterior, transverse and vertical. Significant differences in dimensional changes were noted between the materials over time (p <0.05). Anteroposterior dimensional variation was noted between times, especially for IA and JP. For transverse and vertical variables, a difference was found between the groups, especially at 24 h, 72 h and 120 h. CCC presented significant dimensional shrinkage only at T120 (transverse). IA and JP presented larger dimensional distortions in the vertical measurements. The molding materials used were not dimensionally stable when evaluated after 120 hours of molding. However, such evidence suggests that alginates with longer storage time, such as Cavex Color Change, are more accurate than conventional alginates.

RESUMO O objetivo do presente estudo foi avaliar a precisao e acurácia por meio de análise de modelos digitais de moldes digitalizados obtidos com quatro marcas comerciais de alginato em diferentes tempos. Oitenta moldes de um Typodont padrao foram obtidos utilizando 4 tipos de alginato (CCC: Cavex Color Change; IA: Identic Alginate; HY5: Hydrogum 5 e JP: Jeltrate Plus). Os moldes foram escaneados em quatro tempos: mediatamente (T1), 24h (T2), 72h (T3) e 120h (T4) após a moldagem. As medidas foram feitas em très dimensoes: ântero-posterior, transversal e vertical. Diferenças significativas nas mudanças dimensionais foram observadas entre os materiais ao longo do tempo (p <0,05). Variação dimensional ântero-posterior foi observada entre os tempos, principalmente para IA e JP. Para as variáveis transversal e vertical houve diferenga entre os grupos, principalmente em 24h, 72h e 120h. CCC apresentou contração dimensional significativa apenas em T120 (transversal). IA e JP apresentaram maiores distorções dimensionais na vertical. Os materiais de moldagem utilizados nao foram dimensionalmente estáveis quando avaliados após 120 horas de moldagem. No entanto, tais evidencias sugerem que os alginatos com maior tempo de armazenamento, como Cavex Color Change, sao mais precisos do que os alginatos convencionais.

Uso de scanners intraorais em implantodontia / Uso de los escáneres intrabucales en implantología / Use of intraoral scanners in implantology

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)

In vitro evaluation of the application of digital individual tooth tray in the impression making of mandibular full-arch crown abutments / 北京大学学报(医学版)

OBJECTIVE@#To establish a method for the production of digital individual tooth tray based on three-dimensional (3D) scan, computer-aided design (CAD) and 3D printing, and to evaluate the effect of impression taking of full-arch crown abutments by digital individual tooth tray technique and conventional method through in vitro study.@*METHODS@#The full crown preparation was performed on all the fourteen resin teeth in a standard model of mandibular dentition. The surface data of prepared abutments was collected by 3D scanning. A new project was created in a dental CAD software including all the fourteen teeth in the mandibular dentition. The design modules of anatomy crown and coping were selected for each tooth. The dentition was divided for three sections: right posterior teeth, anterior teeth, and left posterior teeth areas. The connector design was added between the abutments within the same section. The scanned data of the abutments were imported. The occlusal plane and insertion path were determined. The position of margin line, as well as the shape of anatomy crown and connector as the main body of the individual tooth tray were designed for each abutment. The shape of coping was generated as the space for holding the impression material. The finalized data of the main body was imported into Geomagic software. The retentive attachment was added at the external surface and the tissue stop was formed at the internal surface. The completed individual tooth tray was manufactured by 3D printing with resin material. The data of full-arch crown abutments were modified and printed. The conventional dentition trays A and B, as well as digital individual tooth tray were designed and printed for four copies each. The polyether impressions of the full-arch abutments were made by conventional one-step method using dentition tray A, and by sectional-impression technique using digital individual tooth tray and dentition tray B for four times each. The time spent for each impression taking and the numbers of defects at the shoulder and axial/occlusal surface in each impression were recorded. The impression quality of each abutment was evaluated. The overall quality distribution and the pass rate of abutments between the two methods were analyzed.@*RESULTS@#The impressions made by conventional method had more defects at shoulder than those made by digital individual tooth tray technique. No difference of the number of defects at axial/occlusal surface between the two methods was observed. The digital individual tooth tray technique for the full-arch abutment impression exhibited higher pass rate of abutments and better quality of impression, compared with conventional methods.@*CONCLUSION@#A new method for the production of digital individual tooth tray based on digital scanning, CAD and 3D printing was established. Compared with conventional method, using digital individual tooth tray technique for impression taking of full-arch abutments can achieve better effect.

Effect of disinfectant with benzethon chloramine and isopropanol as main active ingredients on the accuracy of dental impression / 北京大学学报(医学版)

OBJECTIVE@#To assess the effect of disinfectant (Cavicide) with benzethon chloramine and isopropanol as main active ingredients disinfectant on dental impression accuracy.@*METHODS@#The effect of Cavicide on three impression materials (alginate, polyether and vinylpolysiloxane) were assessed using a standard model. The standard model was digitized by an extraoral scanner (IScan D103i, Imetric). For each kind of impression materials, thirty impressions were taken following the manufactures' instruction in the same conditions. Subsequently, the impressions were randomly divided into three groups, with ten impressions in each group. After the impression taking was completed, the three groups underwent pure water rinse for 1 min (blank control, BC), 2% glutaraldehyde solution immersion disinfection for 30 min (glutaraldehyde, GD), and Cavicide solution spray disinfection for 5 min (Cavicide, CC), respectively. All the impressions were digitized by the extraoral scanner (IScan D103i, Imetric) after disinfection and exported to a dedicated three-dimensional analysis software (Geomagic Qualify 2014, Geomagic, USA). In the software, the digital models of the impressions were trimmed to teeth and then superimposed with the digitized standard model via best-fit alignment. Root mean square (RMS) was used to evaluate the deviations between the impression and the standard model. The deviation in the anterior and posterior regions was evaluated respectively. One-way ANOVA test and the LSD post-hoc test were used to compare the deviations between the three groups (P < 0.05). The color map of each superimposition was saved for visual analysis.@*RESULTS@#For the polyether and vinylpolysiloxane materials, the difference between the three groups was not statistically significant (P=0.933, P=0.827). For the alginate material, the difference in posterior region between group GD and group BC, as well as group GD and group CC were statistically significant (GD vs. BC, P=0.001; GD vs. CC, P=0.002), while the difference between group BC and group CC was not statistically significant (P=0.854). The visual analysis showed an obvious deviation in the buccal-lingual direction in group GD.@*CONCLUSION@#Disinfectant (Cavicide) with benzethon chloramine and isopropanol as main active ingredients using spray disinfection has no effect on the accuracy of the alginate, polyether and vinylpolysiloxane impressions.

Three-dimensional printed models versus conventional stone models: an accuracy analysis

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

Comparação de Diferentes Técnicas de Moldagem com Silicone de Adição - Estudo in vitro / Comparison of Different Impression Techniques With Addition Silicone - in vitro Study

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.

Dimensional Stability of Casts Derived from Three Types of Alginate at Different Times After Impression

Objective: To evaluate the dimensional changes in three types of alginate following three different delay times after casting. Material and Methods: In this laboratory study, a maxillary arch-shaped stainless steel model was prepared and three pins with similar and determined diameters and heights were placed (one at mid-line and two on the underside of the model) as reference points to compare the dimensional stability of the three types of alginates. A special metal tray was made from the main model. The main moldel was imprisoned by the metal tray, and these were kept for a specific time in a humid environment. Gypsum Type 4 was poured over the impression to obtain 90 gypsum casts for three types of alginate. The dimensions of casts obtained from each alginate were compared in two lateral and anterior-posterior dimensions, they were compared with each other, and the alginates were also compared to the main model. Results: At a time interval of 15 minutes, the dimensional accuracy of the casts obtained from the three types of alginates, with the main model in both anterior-posterior and transverse dimensions was not significantly different (p<0.05); but there was a significant difference at 60 minutes and 24 hours in both dimensions (p<0.05). Although there was no significant difference between the alginates in both dimensions and all three studied time periods, the least difference with the main model was related to Zhermack and the highest difference was related to Golchai alginates. Pairwise comparisons showed that none of the samples had a significant difference in terms of dimensions. Conclusion: The dimensional stability of alginate was a time-dependent type of alginate and had no significant effect on the dimensional accuracy of casts.

Injection Shrinkage аnd Water Sorption of Some Thermoplastic Dental Materials

Objective: To evaluate the change of diameter of different injection-molded thermoplastic materials. Material and Methods: Four thermoplastic injection-molded materials were analyzed (Bre.flex 2nd edition, Vertex ThermoSens, Perflex Biosens and Polyan IC). A total of 432 test samples were made in the form of an "hourglass". All samples were divided into three groups: Group I (Control) - consisting of 36 test samples for each type of material, that was not exposed to artificial aging or a wet environment; Group II - consisting of 36 test samples for each type of material, that were artificially aged through dehydration; Group III - specimen were subjected to artificial aging without dehydration. The diameter of each specimen was measured with a digital caliper. Data were analysed using the Student's t-test. Results: Regarding to shrinkage, the samples from the Bf Control group have a mean value of 1.56 mm and was observed a shrinkage of the injection-molded polyamide material within 0.25%. The comparison between the samples from Group II and Group III showed statistically significant differences (p<0.001). There were no significant differences between groups for Thermosens and Biosens (p>0.05). The comparison between Group II and Group III for Polyan IC samples shows that Group III has a higher arithmetic mean value (p<0.01). Conclusion: Shrinkage of the polymers during the injection process is present in all materials. The thermocycling and the storage in a dry or in a wet environment of the samples results in a change of the diameter in almost every single type of material.

Marginal adaptation of provisional crowns made of acrylic and bisacrylic resins using different impression materials

Aim: To evaluate the marginal adaptation of provisional crowns made of acrylic and bisacrylic resins using different impression materials. Methods: a metal die and a matrix applied through a direct technique were used to fabricate the specimens. The impression materials used as a matrix were divided into four groups: Irreversible hydrocolloid(IH), laboratory silicone (LS), condensation silicone (CS), and addition silicone (AS). After the impression procedures, each matrix was loaded with the provisional prosthetic materials, Alike, Duralay, Protemp 4, and Structur 3 (n = 12). Marginal discrepancy was evaluated using a stereomicroscope at ×45 magnification. The images obtained were transferred to the Corel Draw X7 program, and the distances from the cervical margins of the specimen to the reference lines at the metal die were measured vertically. The data were analyzed by using 2-way ANOVA followed by the Tukey test (α=.05). Results: the acrylic resins had higher values ​​of marginal discrepancy compared to the bisacrylic resins. A statistically significant difference was found between all impression materials, and the irreversible hydrocolloid presented higher values of discrepancy (303.28­613.31 µm), whereas addition silicone had the lowest (48.61­190.06 µm). Conclusions: the bisacrylic resins had a better marginal adaptation compared to the acrylic resins. The addition silicone promoted a better marginal adaptation of the provisional prosthetic materials tested, followed by condensation silicone, laboratory silicone, and irreversible hydrocolloid

Comparison of impression techniques and double pouring by dental cast's accuracy. Preliminary clinical-lab trial

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

Avaliação da estabilidade dimensional da silicona de condensação em diferentes tempos de vazamento em moldagens para prótese fixa / Evaluation of the dimensional stability of the condensation silico-ne in different leakage times in moldings for fixed prosthesis

Introdução: O envelhecimento da população aumenta a necessidade de reabilitação protética e o custo do atendimento odontológico. Para reabilitar com qualidade e baixo custo é necessário conhecer os materiais odontológicos desse processo, como os materiais de moldagem. O mais utilizado no Brasil é a silicona de condensação, que possui limitações. Porém, o fabricante modificou a fórmula com o intuito de melhorar a estabilidade dimensional. Objetivo: avaliar a estabilidade dimensional da silicona de condensação Speedex com a nova tecnologia DCP, em diferentes tempos de vazamento nas moldagens para prótese fixa. Material e métodos: Foi confeccionado um modelo padrão metálico com dois cilindros de mesmos diâmetros e mesma altura para simular uma prótese fixa. Foi elaborada uma moldeira metálica padronizada com retenções e guias de inserção. A partir dessa, outras quatro, em acrílico incolor, foram reproduzidas pelo alginato reversível. No total, foram realizadas 20 impressões, sendo 5 impressões por grupo. Os grupos foram vazados com o gesso tipo IV em diferentes tempos: grupo 1 (n=5): imediato; grupo 2 (n=5): 30 min; grupo 3 (n=5): 36h; grupo 4 (n=5): 72h. O modelo padrão e todos os modelos de gesso do grupo 1, 2, 3 e 4 foram medidos por dois pesquisadores de forma cega com auxílio de um paquímetro digital. Foram analisadas as distâncias externas e internas entre os pontos de referência dos cilindros. Os grupos foram comparados pelo teste t de Student, o nível de significância considerado foi p<0,05. Resultados: não se observou diferença estatística entre as medidas do pesquisador 1 e 2 (p>0,05). Não houveram diferenças entre os grupos 1 e 2 e 1 e 3; porém houve diferença significativa entre o 1 e 4. Conclusão: A silicona de condensação Speedex, não altera a estabilidade dimensional com o vazamento em até 36 horas.

Introduction: The aging of the population increases the need for prosthetic rehabilitation and the cost of dental care. To rehabilitate with quality and low cost is necessary to know the dental materials of this process, such as impression materials. The most used in Brazil is condensation silicon, which has limitations. However, the manufacturer modified the formula to improve dimensional stability. Objective: To evaluate the dimensional stability of Speedex condensation silicon with the new DCP technology at different casting times in fixed prosthesis moldings. Material and methods: A standard metal model with two cylinders of the same diameters and the same height was made to simulate a fixed prosthesis. A standard metal tray with drawers and insertion guides was developed. This metal tray was duplicated using reversible alginate. From this, four colorless acrylic trays were reproduced. In total, 20 impressions were made, with 5 impressions per group. The groups were cast with type IV gypsum at different times: group 1 (n=5): immediate; Group 2 (n=5): 30 min; group 3 (n=5): 36h; group 4 (n=5): 72h. The standard model and all gypsum models of groups 1, 2, 3 and 4 were measured by two researchers blindly using a digital caliper. The external and internal distances between the reference points of the cylinders were analyzed. The groups were compared by Student's t test, the significance level considered was p<0.05. Results: no statistically significant difference was found between researcher 1 and 2 by (p<0.05). There were no differences between groups 1 and 2 and 1 and 3; however, there was a significant difference between 1 and 4. Conclusion: Speedex condensing silicone does not change dimensional stability with leakage within 36 hours. Key-words: Dental Impression Materials, Dental Prosthesis, Silicone Elastomers. Submetido: 14/06/2019Aceito: 16/08/2019 Rebeca Vidal Capelupi1,2,Viviam Salvato de Souza1,2,Marcelo Tarcísio Martins1,Júlio Marcos Gouvêa Chagas1,Rogério Teodoro de Aquino3,Thalyta dos Reis Furlani Zouain-Ferreira1,Fabiana Aparecida Mayrink de Oliveira1,21Faculdade de Ciências Médicas e da Saúde de Juiz de Fora, Curso de Odontologia ­ Juiz de Fora, MG. 2Programa Institucional de Bolsas de Iniciação Científica (PIBIC) ­ FCMS/JF 2018.2 3Usinagem Mecânica Industrial, SENAI, Juiz de Fora, MG. Avaliação da estabilidade dimensional da silicona de condensação em diferentes tempos de vazamento em moldagens para prótese fixaEvaluation of the dimensional stability of the condensation silico-ne in different leakage times in moldings for fixed prosthesis * Fabiana de OliveiraAvenida Barão do Rio Branco, 1871/1105, CentroJuiz de Fora ­ MG CEP: 36013-020 8 fabsmay@hotmail.com