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Niger J Clin Pract ; 23(3): 284-290, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32134024


Aims: The aim of this study was to determine the best approach to reduce the unfavorable change in the three different dimensions of impressions using disinfection durations of 15 and 30 min; three different disinfection procedures; and alginate impression products as research factors. Materials and Methods: CA37, impressional, and cream alginate impressions were used; distortion in the AB, AC, and BC dimensions of impressions using disinfection durations of 15 and 30 min was studied; and no disinfection (ND), conventional disinfection (CD), and sonicator-activated disinfection (SAD) procedures were measured. Results: Regarding AB dimension, the impressional has best performance when CD was applied for both 15 and 30 min. When SAD was applied for 15 min, impressional and cream alginates provide best performance. When CD was applied for 15 min, CA37 and impressional alginates provide best performance. Although ND-applied CA37 alginate after 30 min provides best performance, because of many outlier values, its implication may not be considered as meaningful. Regarding AC dimension, cream alginate has best performance when CD was applied for 15 min. The AC distances in all the alginates are considerably different from the base model after 30 min. Regarding BC dimension, only the CA37 alginate has the best performance when ND was applied for 15 min. All the alginates are considerably different from that of the base model after 30 min. Conclusion: Preference of 15-min disinfection can provide favorable results to obtain all impressions with minimally distorted dimensions. CD is an adequate procedure. The studied SAD needs to be developed further. All alginates are comparably successful to obtain impressions with desired distortion degrees.

Alginatos/química , Desinfetantes de Equipamento Odontológico/administração & dosagem , Desinfetantes de Equipamento Odontológico/química , Materiais para Moldagem Odontológica/química , Desinfecção/métodos , Esterilização/métodos , Técnica de Moldagem Odontológica , Modelos Dentários , Humanos , Controle de Infecções Dentárias/métodos , Teste de Materiais/métodos , Fatores de Tempo
Mater Sci Eng C Mater Biol Appl ; 104: 109961, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31500022


Formation of fungal biofilms on health care-related materials causes serious clinical consequences. This study reports a novel fungal repelling strategy to control fungal biofilm formation on denture biomaterials through layer-by-layer self-assembly (LBL). Amphiphilic quaternary ammonium chitosans (CS612) were synthesized and used as the antimicrobial positive layer, and sodium alginate (SA) was chosen as the negative layer to construct LBL multilayers on poly (methyl methacrylate) (PMMA)-based denture materials. The presence of LBL multilayers on denture disc was confirmed and characterized by surface zeta potential, water contact angle, AFM, and FT-IR analyses. The multilayer coatings, especially CS612 as the outmost layer, effectively prevented the fungal initial adhesion and biofilm formation. The Candida cells avoided the multilayer coatings and suspended in broth solution instead of forming biofilms, suggesting that the LBL multilayers had fungal repelling effects. The LBL multilayers were biocompatible toward mammalian cells. In stability tests, after immersion in PBS for 4 weeks under constant shaking and repeated brushing with a denture brush for up to 3000 times, the biofilm-controlling effects of the LBL multilayers were not affected, pointing to a novel long-term strategy in controlling fungal biofilms on denture and other related biomaterials.

Alginatos/química , Compostos de Amônio/química , Biofilmes/efeitos dos fármacos , Candida/efeitos dos fármacos , Quitosana/química , Materiais Revestidos Biocompatíveis/farmacologia , Materiais Dentários/farmacologia , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Materiais Revestidos Biocompatíveis/química , Materiais Dentários/química , Polimetil Metacrilato/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Propriedades de Superfície/efeitos dos fármacos
Angle Orthod ; 89(6): 868-875, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31259615


OBJECTIVE: To compare patient experience, chairside time, dental arch distances, and costs of dental models derived from intraoral scans and alginate impressions in pre-orthodontic children and young adolescents. MATERIALS AND METHODS: Fifty-nine children and young adolescents (9-15 years, mean: 12.70 years) had an intraoral scan and an alginate impression prior to orthodontic treatment. During the procedures, chairside time was registered in minutes and patient experience was assessed by a Visual Analogue Scale questionnaire. Four maxillary dental arch distances were measured on digital models, on plaster casts, and directly in the mouth (intraoral). The cost of each procedure was presented graphically. Differences between the two procedures were tested by paired t-test and general linear model. RESULTS: Patient experience was statistically better during intraoral scan compared with alginate impression regarding comfort, gag reflex, breathing, smell/sound, taste/vibration, and all statements concerning anxiety (P < .05). No significant difference in chairside time between the two procedures was found. No statistically significant differences in dental arch distances between digital models and plaster casts were found, but dental arch distances measured intraorally differed significantly from both digital models and plaster casts (P < .05). Cost calculation showed that the digital procedure was 10.7 times more expensive than the conventional procedure initially and, that after 3.6 years, the two procedures were equal in cost. CONCLUSIONS: Children preferred intraoral scan rather than alginate impression. Chairside time was equal for the two procedures as were the measurements of maxillary dental arch distances. The two procedures were equal in cost at 3.6 years.

Arco Dental , Modelos Dentários , Adolescente , Alginatos , Criança , Desenho Assistido por Computador , Materiais para Moldagem Odontológica , Técnica de Moldagem Odontológica , Humanos , Imageamento Tridimensional
Pesqui. bras. odontopediatria clín. integr ; 19(1): 4137, 01 Fevereiro 2019. tab
Artigo em Inglês | LILACS, BBO - Odontologia | ID: biblio-998205


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.

Técnica de Moldagem Odontológica , Modelos Dentários , Alginatos , Precisão da Medição Dimensional , Análise de Variância , Materiais para Moldagem Odontológica , Irã (Geográfico)
Am J Orthod Dentofacial Orthop ; 154(5): 733-739, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30384944


INTRODUCTION: A rapidly advancing digital technology in orthodontics is 3-dimensional (3D) modeling and printing, prompting a transition from a more traditional clinical workflow toward an almost exclusively digital format. There is limited literature on the accuracy of the 3D printed dental models. The aim of this study was to assess the accuracy of 2 types of 3D printing techniques. METHODS: Digital and alginate impressions of the oral environment were collected from 30 patients. Subsequently, digital impressions were used to print 3D models using digital light processing (DLP) and polyjet printing techniques, and alginate impressions were poured up in stone. Measurements for the 3 model types (digital, DLP, and polyjet) were compared with the stone models. Tooth measurements (first molar to first molar) included mesiodistal (crown width) and incisal/occlusal-gingival (crown height). Arch measurements included arch depth and intercanine and intermolar widths. Intraobserver reliability of the repeated measurement error was assessed using intraclass correlation coefficients. RESULTS: The intraclass correlation coefficients were high for all recorded measurements, indicating that all measurements on all model types were highly reproducible. There were high degrees of agreement between all sets of models and all measurements, with the exception of the crown height measurements between the stone and DLP models, where the mean difference was statistically significant. CONCLUSIONS: Both the DLP and polyjet printers produced clinically acceptable models and should be considered viable options for clinical application.

Técnica de Moldagem Odontológica , Modelos Dentários , Impressão Tridimensional , Alginatos , Materiais para Moldagem Odontológica , Ácido Glucurônico , Ácidos Hexurônicos , Humanos , Ortodontia/organização & administração , Fluxo de Trabalho
Prosthes. Esthet. Sci ; 7(28): 72-79, jul-set 2018. ilus, tab, graf
Artigo em Português | BBO - Odontologia | ID: biblio-946485


O hidrocolóide irreversível por sua baixa estabilidade dimensional requer vertimento imediato do gesso. A fim de tornar sua utilização mais versátil, tem-se proposto formulações que indicam a possibilidade de vertimento do gesso no molde em até 5 dias após a moldagem. O objetivo neste estudo foi investigar o efeito do tempo de espera de armazenamento do molde na estabilidade dimensional linear do hidrocolóide irreversível (Hydrogum 5®, Zhermack). Para tal, foi confeccionado um modelo mestre em cromo-cobalto, com quatro pilares cilíndricos localizados na região de caninos e molares. Desse modelo mestre foram obtidos 40 moldes, que foram distribuídos em 4 grupos (n = 10), de acordo com os tempos de espera para vertimento do gesso tipo IV (Herostone®, Vigodent): imediatamente, 1, 3 e 5 dias após a moldagem. Os moldes foram mantidos em cuba umidificadora a 23° C. Para avaliação da estabilidade dimensional dos moldes obtidos, realizou-se a medição linear das distâncias, com paquímetro digital, entre os pilares dos modelos na região de caninos (pilares A e B) e de molares (pilares C e D), de modo que foram mensuradas as distâncias AB, AC, AD, BD, BC e CD e comparadas com as do modelo mestre. A alteração dimensional foi de -0,20 a +0,33 mm, indicando, portanto, contração e expansão, mas com excelente replicabilidade em relação ao modelo mestre. A análise de variância a dois critérios e o teste de Tukey demonstraram que o tempo de armazenamento influenciou a alteração dimensional, havendo diferença entre os dias 1 (contração) e 5 (expansão) (p = 0,039), independentemente da localização. Não houve diferença nas alterações dimensionais nas distâncias comparadas (p = 0,081), independentemente dos tempos estudados. Os resultados demonstraram que as medidas do modelo mestre foram replicadas de maneira excelente em todos os tempos decorridos da moldagem, sendo possível considerar que através de moldes de Hydrogum 5®, mesmo cinco dias após o procedimento de moldagem, podem ser obtidos modelos de gesso com estabilidade dimensional aceitável. (AU)

Irreversible hydrocolloid due to its low dimensional stability requires immediate plaster casting. In order to make its use more versatile, formulations have been proposed which indicate a possibility of casting the gypsum in the mold within 5 days after a molding. The objective of this study was to investigate the effect of mold storage time on linear dimensional stability of irreversible hydrocolloid (Hydrogum 5®, Zhermack). For this, a master model was made in chrome-cobalt, with four cylindrical pillars located in the region of canines and molars. From this master model, 40 molds were obtained, which were distributed in 4 groups (n = 10), according to waiting times for cast type IV gypsum (Herostone®, Vigodent): 1, 3 and 5 days after the molding. The molds were kept in a humidifier container at 23 ° C. To evaluate the dimensional stability of the molds obtained, perform a linear measurement of the distances, with digital caliper, between the pillars of the models in the region of canines (A and B pillars) and molars (columns C and D), so that they were measured as AB, AC, AD, BD,BC and CD distances and compared as a model. The dimensional change was from -0.20 to +0.33 mm, indicating, therefore, contraction and expansion, but with excellent replicability in relation to the master model. An analysis of variance at two criteria and Tukey's tests demonstrated the storage time influenced the dimensional change, with difference between days 1 (contraction) and 5 (expansion) (p = 0.039), regardless of location. There were no differences in size at the distances compared (p = 0.081), regardless of the times studied. The results are shown as measurements of the master model with excellent replicates at all times after molding, it being possible to assume that by means of Hydrogum 5® molds, even five days after the molding procedure, of plaster with acceptable dimensional stability. (AU)

Sulfato de Cálcio/análise , Materiais para Moldagem Odontológica , Materiais Dentários , Alginatos
Indian J Dent Res ; 29(4): 477-486, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30127200


Purpose: The purpose of this study was to assess and compare the dimensional accuracy of the stone casts made of three extended pour alginate impressions materials (Cavex Colorchange, Kromopan, and Neocolloid) following storage under different storage conditions and pouring at different time intervals. Materials and Methods: A maxillary Frasaco (dentulous) model was selected as a standard model. Index holes of 1 mm depth and 1 mm diameter were made on the palatal cusp tips of right and left first premolars, mesiopalatal cusp tips of right and left third molars and in the midline of the palate, perpendicular to a line joining the index holes made on cusp tips of the first premolars as reference points for measurement. A single uniformly spaced custom tray was fabricated with heat-cure acrylic resin and used to make impressions for the entire study. A total of 210 impressions of the master model were made, seventy impressions were made from each of the alginate material brands and were subjected to three storage conditions (open air, uncontrolled humidity, and 100% controlled humidity) for three different storage time intervals (0, 1, 6 h). Since no storage was done in the immediate-pour group, it contained 10 specimens from each brand. Following the designated storage time interval, all impressions were poured in type IV gypsum. Measurements of stone casts were done in three dimensions, anteroposterior, lateral using Measuroscope and vertical by Dial Gauge. Data were organized in tables and statistical analyses were performed. Three-way ANOVAs were used to check if the material brands, storage time intervals, and conditions affect the measurements. Tukey HSD post hoc tests were used for the multiple comparisons if ANOVA is significant. One sample t-test was used to compare between the casts made of alginate brands and the master model. Significance level was set to α < 0.05 for all tests. Results: Results showed that the material brands, storage time intervals, and conditions do affect the measurements in all three dimensions (all P < 0.05). In addition, all two-way and three-way interactions were significant for all measurements except the interaction of storage time intervals and conditions for B-C (lateral) measurements, and interaction of material brands and storage time intervals for C-D (anteroposteriorly) measurements. When stone casts were compared to the master model, immediate pour, and storage for 1 h in 100% controlled humidity resulted in statistically insignificant changes among all three alginate impression brands. In addition, the specimens made of Cavex Colorchange and Kromopan following storage in uncontrolled humidity condition for 1 h showed statistical insignificance when compared to the master model. Conclusion: Within the limitations of this study, it can be extrapolated that, although this class of alginate impression materials was manufactured for extended pour purposes, clinicians should avoid storage of the studied brands for 6 h. Whenever 1 h to pour is necessary, 100% controlled humidity is the ideal and standardized environment for all three alginate brands. Perhaps, Cavex Colorchange, and Kromopan can be safely stored in uncontrolled humidity condition while maintaining their optimal dimensional accuracy.

Alginatos , Materiais para Moldagem Odontológica , Umidade , Teste de Materiais , Ar , Sulfato de Cálcio , Coloides , Revestimento para Fundição Odontológica , Modelos Dentários , Fatores de Tempo
J. health sci. (Londrina) ; 20(2)30/06/2018.
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-909318


Alginate is among the most used materials in dentistry to create teeth negative printing and reproduction. The goal of this study was to compare dimensional changes of alginate scanned impression materials. Thirty impressions of a standard typodont were performed using three types of alginate (Hydrogum 5; Jeltrate Plus and Avagel). The impressions were scanned by the scanner 3Shape R700T and scans were performed immediately after molding. The analysis of digital models were performed at OrthoAnalyzer ™ 3D software. Measurements were carried out in relation to the transverse dimension (intercanine, interpremolares and intermolar). Method error was evaluated through the Intraclass Correlation Coefficient (ICC) and Bland-Altman. One-way ANOVA, Dunnet Post-test were used to compare the different groups in relation to Typodont (gold standard) for the different outcome variables. The data were tabulated in Statistical Package for Social Sciences version 20.0 and Minitab 17.0 softwares to compare groups. The significance level was 5%. The posterior transverse variables (D1PM, D2PM and DM) presented a statistically significant difference regarding the gold standard (Typodont) for the plaster models performed after the Avagel molding. In the digital models performed just after molding, only in DM, the Avagel material group presented values statistically higher than the control group. The alginates Hydrogum 5 and Jeltrate Plus presented dimensions closer to the gold standard.(AU).

O alginato está entre os materiais de moldagem mais utilizados na Odontologia para criar impressão e reprodução negativa dos dentes. O objetivo desse trabalho foi comparar alterações transversais de três marcas comerciais de alginato (Hydrogum, Jeltrate e Avagel) em moldes de alginatos. Trinta moldes de um Typodont padrão foram realizados, utilizando três tipos de alginato (Hydrogum 5; Jeltrate Plus e Avagel). Os moldes foram escaneados por meio do scanner 3Shape R700T e os escaneamentos realizados logo após a moldagem e logo após a obtenção dos modelos de gesso. As análises dos modelos digitais foram realizadas no software OrthoAnalyzer™ 3D. Foram realizadas mensurações em relação à discrepância transversal (inter-caninos, inter-primeiro pré-molar, inter-segundo pré-molar e inter-molares). O erro do método foi avaliado por meio do Coeficiente de Correlação Intraclasse (CCI) e Bland-Altman. Utilizou-se Análise de Variância (one-way ANOVA, Pós-teste Dunnet) para comparação dos diferentes grupos em relação ao typodont (padrão-ouro) para as diferentes variáveis de desfecho. A análise estatística foi realizada nos programas Statistical Package for Social Sciences versão 20.0 e no programa Minitab 17.0 para comparação dos grupos. O nível de significância foi de 5%. As variáveis transversais posteriores (D1PM; D2PM e DM) apresentaram diferença estatisticamente significante em relação ao padrão-ouro (manequim) para os modelos de gesso realizados após a moldagem com Avagel. Nos modelos digitais realizados logo após a moldagem, apenas na DM, o grupo do material Avagel apresentou valores estatisticamente maiores do que o grupo controle. Os alginatos Hydrogum 5 e Jeltrate Plus apresentaram dimensões mais próximas do padrão-ouro.(AU).

Am J Orthod Dentofacial Orthop ; 153(4): 534-541, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29602345


INTRODUCTION: Recent technological advances have made intraoral scans and digital models a possibility and a promising alternative to conventional alginate impressions. Several factors should be examined when considering an intraoral scanner, including patient acceptance and efficiency. The objectives of this study were to assess and compare patient satisfaction and time required between 2 intraoral scanners and conventional alginate impressions. METHODS: An initial pilot study was completed to create a valid and reliable survey instrument that would measure 3 areas of patient satisfaction with the impression experience. A visual analog scale survey was developed and administered to 180 orthodontic patients receiving 1 of 3 types of impressions: (1) iTero Element intraoral scan (Align Technologies, San Jose, Calif), n = 60; (2) TRIOS Color intraoral scan (3Shape, Copenhagen, Denmark), n = 60; and (3) conventional alginate impression (imprEssix Color Change; Dentsply Sirona, York, Pa), n = 60, and the time required to obtain the impressions was recorded. RESULTS: Reliability was evaluated with intraclass correlation coefficient values for 17 paired questionnaires, and all questions were found to be reliable (intraclass correlation coefficient, ≥0.65). For the main study, 180 subjects completed timed impressions and surveys. Data indicated that subjects receiving intraoral scans preferred the digital impressions, and subjects receiving alginate impressions were neutral regarding impression preference, and that efficiency varied based on the impression method. CONCLUSIONS: Intraoral scanners are accepted by orthodontic patients, and they have comparable efficiency with conventional impression methods depending on the type of scanner.

Alginatos , Técnica de Moldagem Odontológica/instrumentação , Processamento de Imagem Assistida por Computador/instrumentação , Satisfação do Paciente , Percepção do Tempo , Adolescente , Adulto , Criança , Desenho Assistido por Computador , Materiais para Moldagem Odontológica , Modelos Dentários , Feminino , Ácido Glucurônico , Ácidos Hexurônicos , Humanos , Imageamento Tridimensional/instrumentação , Masculino , Pessoa de Meia-Idade , Ortodontia , Projetos Piloto , Reprodutibilidade dos Testes , Inquéritos e Questionários , Adulto Jovem
J Dent ; 68: 98-103, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29054679


OBJECTIVES: To compare the cost and to evaluate cost-effectiveness of fabricating mandibular complete dentures (CDs) using two different impression methods. METHODS: A crossover randomized controlled trial including 27 edentulous participants was performed. Mandibular CDs were fabricated using two different impression methods, as follows: (i) conventional method using a custom tray border moulded with impression compound and silicone and (ii) simplified method using a stock tray and alginate. Cost analysis was performed from a clinical practitioner's perspective. The total cost included labor cost, which was calculated using the time spent by dentists and technicians in fabricating CDs and their hourly wages, and the material costs, which were calculated using purchase prices. To evaluate cost-effectiveness, we used general patient satisfaction as an indicator of effectiveness and calculated the incremental cost effectiveness ratio (ICER). ICER represents the cost per one unit of effectiveness. RESULTS: The trial was completed by 24 participants. The total cost was 43,904 Japanese Yen (JPY) (330.91 EUR / 395.78 USD) for the conventional method and 39,792 JPY (299.93 EUR / 358.70 USD) for the simplified method, and this difference was statistically significant (p<0.001). The ICER showed a cost of 633 JPY (4.77 EUR / 5.70 USD) for every one point change in general patient satisfaction. CONCLUSIONS: The results indicated that the total cost of the conventional method was significantly higher than that of the simplified method (p<0.001). CLINICAL SIGNIFICANCE: The conventional impression method for fabricating mandibular CDs, which took additional 633 JPY (4.77 EUR / 5.70 USD) for improvement of general satisfaction, is supposed to be clinically meaningful1.

Análise Custo-Benefício , Técnica de Moldagem Odontológica/economia , Planejamento de Prótese Dentária/economia , Planejamento de Prótese Dentária/métodos , Prótese Total/economia , Alginatos , Custos e Análise de Custo , Estudos Cross-Over , Materiais Dentários/economia , Técnicos em Prótese Dentária/economia , Odontólogos/economia , Planejamento de Dentadura/economia , Mandíbula , Boca Edêntula/terapia , Satisfação do Paciente , Silicones , Fatores de Tempo , Tóquio
Braz. dent. sci ; 21(1): 37-43, 2018. ilus, tab
Artigo em Inglês | LILACS, BBO - Odontologia | ID: biblio-881830


Objective: The aim of this study was to evaluate dimensional stability and detail reproduction in alginate molds stored at different times and temperatures. Material and Methods: Three different commercially available alginates (Cavex Color Change, Jeltrate Plus and Hydrogum 5) were tested at four different times (0 - control, 1, 3 and 5 days) and two temperatures (25ºC and 37ºC) (n=5). The alginates were handled following the manufacturer's instructions. The impression procedures occurred in an environment with controlled room temperature (25ºC) and relative humidity (50±5%). A metallic model (ISO 1563:1990) was used to perform the impressions. The tray containing alginate remained on the metallic model under constant pressure (2 kgf) until the alginate gelation process. The molds were stored (different times and temperatures) and analyzed in stereomicroscope at 30x magnification and 0.5 µm accuracy (Olympus Measuring Microscope STM). The molds and the metallic model measurements were compared, and the data were statistically analyzed by Kolmogorov-Smirnov and three-way ANOVA tests, and the means were compared by Tukey test (5%). Results: The results showed no double interactions (p>0.05) and the different alginates presented statistically similar values of dimensional stability (p=0.102). However, 25ºC (temperature) and control group (time) showed the highest values of dimensional stability (p <0.05). Jeltrate Plus was the only material that presented inaccuracy in details reproduction. Conclusion: It is recommended that, for tested alginates, the stone casts should be poured immediately, even though the molds are dimensionally stable up to 5 days when stored at 25ºC.(AU)

Objetivo: O objetivo neste estudo foi avaliar a estabilidade dimensional e a reprodução de detalhes em moldes de alginatos armazenados em diferentes tempos e temperaturas. Material e Métodos: Foram testadas três diferentes marcas de alginato (Cavex ColorChange, Jeltrate Plus e Hydrogum 5), sendo que esses materiais foram armazenados por quatro diferentes tempos (0 - controle, 1, 3 e 5 dias) e duas diferentes temperaturas (25ºC e 37ºC) (n=5). Os alginatos foram manipulados seguindo as instruções do fabricante. A moldagem ocorreu em um ambiente com temperatura (25ºC) e umidade relativa (50±5%) controladas. Foi utilizado um modelo metálico (ISO 1563:1990) para a realização das moldagens. A moldeira contendo o alginato permaneceu sobre o modelo metálico sob pressão constante de 2 kgf até a geleificação do material. Em seguida, os moldes foram armazenados nos tempos e temperaturas testados, sendo posteriormente avaliados sob um microscópio comparador (Olympus Measuring Microscope STM) com precisão de 0,5 µm. As medidas dos moldes de alginato foram comparadas com as medidas do modelo metálico padrão, sendo os dados analisados estatisticamente pelos testes de Kolmogorov-Smirnov e ANOVA três fatores, sendo as médias foram comparadas pelo teste de Tukey (5%). Resultados: Os resultados mostraram nenhuma interação dupla (p>0,05), sendo que os diferentes alginatos apresentaram valores de estabilidade dimensional estatisticamente semelhantes entre si (p=0,102). Já a temperatura de 25ºC e o grupo controle (tempo) mostraram os maiores valores de estabilidade dimensional (p <0,05). O Jeltrate Plus foi o único material que apresentou imprecisão na reprodução de detalhes. Conclusão: Recomenda-se que os alginatos testados tenham os modelos de gesso vazados imediatamente, apesar dos moldes serem dimensionalmente estáveis até 5 dias desde que armazenados a 25ºC. (AU)

Materiais para Moldagem Odontológica , Precisão da Medição Dimensional
J Contemp Dent Pract ; 18(10): 911-914, 2017 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-28989129


INTRODUCTION: Alginate is a versatile, irreversible hydrocolloid impression material, which is cost-effective and forms an essential component in dental practice. For elevating the hardness of the cast models, hardeners are combined with stone. Hence, we planned the present study to evaluate the impact of altering the time of contact between alginate and stone after various interim periods. MATERIALS AND METHODS: The present study included the assessment of impact of time of contact between alginate and stone by the construction of 90 casts using a cylinder model. Two bisecting lines were marked and were named as y and y'. These lines were used for testing the dimensional stability. Using chemically cured acrylic resin, the construction of ten special trays was done. All the impression casts were randomly divided into two study groups, with 45 casts in each group-group I: control group, casts were removed after 60 minutes; group II: study group, casts were removed after 9 hours. A digital caliper was used for measuring the dimensional stability of the cast. All the data were collected and analyzed. RESULTS: In the specimens of the control group (group I) and the study group (group II), the mean dimensions from y to y' were found to be 17.54 and 17.95 respectively. The mean reading of hardness in the control group and study group was found to be 0.59 and 0.20 respectively. In groups I and II, the number of specimens showing clarity of two lines (X and X") was 0 and 5 respectively. CONCLUSION: There was no change in the dimensional stability of the dental stone model when the contact time was increased. CLINICAL SIGNIFICANCE: Within certain limits, the contact time between alginate and stone can be altered without significantly altering the properties of the cast.

Alginatos/metabolismo , Sulfato de Cálcio/metabolismo , Modelos Dentários , Técnica de Fundição Odontológica , Materiais para Moldagem Odontológica/metabolismo , Ácido Glucurônico/metabolismo , Ácidos Hexurônicos/metabolismo , Humanos , Técnicas In Vitro , Fatores de Tempo
Niger J Clin Pract ; 20(9): 1175-1181, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29072243


OBJECTIVES: The aim of this study was to evaluate the accuracy of digital models produced with the three-dimensional dental scanner, and to test the dimensional stability of alginate impressions for durations of immediately (T0), 1 day (T1), and 2 days (T2). MATERIALS AND METHODS: A total of sixty impressions were taken from a master model with an alginate, and were poured into plaster models in three different storage periods. Twenty impressions were directly scanned (negative digital models), after which plaster models were poured and scanned (positive digital models) immediately. The remaining 40 impressions were poured after 1 and 2 days. In total, 9 points and 11 linear measurements were used to analyze the plaster models, and negative and positive digital models. Time-dependent deformation of the alginate impressions and the accuracy of the conventional plaster models and digital models were evaluated separately. RESULTS: Plaster models, negative and positive digital models showed significant differences in nearly all measurements at T (0), T (1), and T (2) times (P < 0.01, P < 0.05, and P < 0.001). Arch perimeter measurements did not differ at T (0) and T (1) times (P > 0.05), but they demonstrated statistically significant differences at T (2) time (P < 0.05) between the models. CONCLUSIONS: This study showed that measurements on negative digital models offer a high degree of validity when compared to measurements on positive digital models and plaster models; differences between the techniques are clinically acceptable. Direct scanning of the impressions is practicable method for orthodontists.

Alginatos/química , Materiais para Moldagem Odontológica/química , Técnica de Moldagem Odontológica , Modelos Dentários , Processamento de Imagem Assistida por Computador , Imageamento Tridimensional/métodos , Feminino , Humanos , Processamento de Imagem Assistida por Computador/métodos , Masculino , Teste de Materiais , Reprodutibilidade dos Testes , Fatores de Tempo , Dente
Rev. Odontol. Araçatuba (Impr.) ; 38(3): 27-33, set.-dez. 2017. tab, graf, ilus
Artigo em Português | LILACS, BBO - Odontologia | ID: biblio-881656


Este é um estudo cuja finalidade foi demonstrar as possíveis deformações que podem ocorrer nos modelos obtidos de moldes de alginato, dependentes da forma de vazamento. Foram obtidos 20 moldes de alginato da marca Hydrogum 5 (Zhermack, Badia Polesine, Italy), através de um modelo de resina acrílica previamente preparado, divididos em dois grupos de 10: com vazamento invertido e não invertido. Os modelos foram analisados por fotografias, mensurados por um programa de computação (Corel Draw X3 Graphics Suíte (Corel Corporation ­ USA) e comparados com o modelo padrão. Os resultados mostraram que os vazamentos invertidos e não invertidos apresentaram valores clínicos diferentes do modelo padrão, mas que na comparação entre as técnicas, dos quatro segmentos analisados, apenas um apresentou diferença estatística significante(AU)

This is a study whose purpose was to demonstrate the possible deformations that may occur in the models obtained from alginate molds, depending on the form of flow. 20 alginate molds of Hydrogum 5 (Zhermack, Badia Polesine, Italy) were obtained through a previously prepared acrylic resin model, divided into two groups of 10: with inverted and non inverted casting. The models were analyzed by photographs, measured by a computer program (Corel Draw X3 Graphics Suite (Corel Corporation - USA) and compared with the standard model.The results showed that inverted and non inverted flow presented clinical values different from the standard model, But that in the comparison between the techniques, of the four analyzed segments, only one presented significant statistical difference(AU)

Alginatos , Materiais para Moldagem Odontológica
Prosthes. Lab. Sci ; 6(24): 58-64, jul.-set. 2017. ilus
Artigo em Português | BBO - Odontologia | ID: biblio-877531


Este artigo descreve a utilização de alginato e silicone de adição para a obtenção de moldes, preliminares e definitivos, em casos de moldagens de pacientes edêntulos.

This article describes the use of alginate and vinyl polysiloxane to obtain preliminar and functional impressions for edentulous patients.

Humanos , Materiais para Moldagem Odontológica , Técnica de Moldagem Odontológica/instrumentação , Materiais Dentários , Silicones/uso terapêutico
Prosthes. Lab. Sci ; 6(24): 92-98, jul.-set. 2017. ilus, tab
Artigo em Português | BBO - Odontologia | ID: biblio-877656


O objetivo deste trabalho foi comparar, por meio de medições tridimensionais, modelos de gesso obtidos a partir de duas técnicas de moldagem preliminar: godiva (GG) e dupla moldagem com alginato (GA). Para isso, foi utilizado um modelo padrão metálico com três cilindros posicionados na região de molares esquerdo (A) e direito (B) e na região de papila incisiva (C). Para GG foi realizada a moldagem convencional com material plastificado entre 60-65°C. Para GA foi utilizada a técnica da mínima pressão equalizada, com a primeira moldagem realizada seguindo a proporção indicada pelo fabricante e a segunda com aumento de 25% na quantidade de água. Para avaliação da distorção, os modelos de gesso de cada grupo foram submetidos às medições tridimensionais em equipamento por coordenadas (n=10/grupo). O plano de nivelamento foi considerado no topo dos três cilindros e o centro de origem pela simetria dos cilindros A e B, permitindo a aferição da distância entre os cilindros (AB e BC), o diâmetro de cada cilindro (A, B e C) e a altura do palato. Os dados foram analisados por ANOVA 2 fatores e teste de Tukey (α=0.05). houve influência da interação do material de moldagem e localização das medidas (p0.05) entre os grupos, GG resultou em maior alteração dimensional nas mensurações dos diâmetros A, B e C. GG e GA não diferiram na estabilidade dimensional, portanto sendo consideradas técnicas clinicamente viáveis.

The aim of this study was to compare, through three-dimensional measurements, stone casts obtained by two preliminary impression techniques: compound (CG) and double-alginate (AG) impression. for this purpose, a metal pattern model with three cylinders positioned in the left (A) and right (B) molars and incisal papilla (C) regions was used. for CG, conventional impression with plasticized material between 60-65°C was carried out. for AG, the equalized minimum pressure technique was used with the first impression taken according to the proportion indicated by the manufacturer, and the second with 25% increase in the water quantity. To evaluate the distortion, the stone casts of each group were submitted to three-dimensional measurements in equipment by coordinates (n=10/group). The leveling plane was considered at the top of the three cylinders, and the center of origin by A and B cylinders symmetry, which allowed measurement of the distance between the cylinders (AB and BC), diameter of each cylinder (A, B and C) and palate height. The data were evaluated by two-way ANOVA and Tukey tests (α=0.05). There was influence on the interaction of impression material and location of the measurements (p0.05) between the groups, CG resulted in greater dimensional change in the measurements of A, B and C diameters. CG and AG did not differ in dimensional stability, thus being considered clinically feasible techniques.

Humanos , Alginatos , Materiais para Moldagem Odontológica , Técnica de Moldagem Odontológica , Materiais Dentários
Compend Contin Educ Dent ; 38(6): e1-e4, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28586232


Alginate impression (irreversible hydrocolloid) material is commonly used in dental practice because it is easy to mix, low in cost, and well tolerated by patients. The material is not dimensionally stable, however; thus, it is necessary to pour the impression immediately after the molding is accomplished, or within 60 minutes if the impression is kept in 100% humidity. Excessive contact of the alginate impression with the cast model over time may affect the model's properties. In this study, the authors tested the effect of contact time between an alginate impression and type III dental stone on cast model properties. Sixty-seven cast models were obtained from a stainless steel cylinder by using irreversible hydrocolloid impression material and type III dental stone. Thirty-seven cast models were separated from the impression after 1 hour (control group) and 30 cast models were separated after 6 hours (study group). The samples were evaluated under light microscope for surface details and measured by digital caliper for dimensional stability. An indentation on the cast was made and the depth of the indentation was then measured with a digital caliper to measure hardness. The dimensional stability of the cast models was not affected when contact time was increased from 1 hour to 6 hours (P = .507). Surface details did not deteriorate when contact time was increased, as all of the samples could reproduce all details after the 1-hour and 6-hour interval periods. However, hardness was greater after 1 hour of contact time (P = .001) than after 6 hours of contact time. In conclusion, contact between alginate impression material and type III dental stone up to 6 hours did not affect the dimensional stability and richness of the surface; hardness, though, was significantly affected.

Alginatos/química , Sulfato de Cálcio/química , Materiais para Moldagem Odontológica/química , Materiais para Moldagem Odontológica/normas , Técnica de Moldagem Odontológica/instrumentação , Materiais Dentários/química , Modelos Dentários , Testes de Dureza , Umidade , Teste de Materiais/estatística & dados numéricos , Microscopia , Aço Inoxidável , Propriedades de Superfície , Fatores de Tempo
Int J Prosthodont ; 30(1): 33-37, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28085976


PURPOSE: The aim of this study was to analyze the clinical fit of metal-frame partial removable dental prostheses (PRDPs) based on custom trays used with alginate or polyvinyl siloxane impression material. MATERIALS AND METHODS: Fifth-year students of the Nijmegen Dental School made 25 correct impressions for 23 PRDPs for 21 patients using alginate, and 31 correct impressions for 30 PRDPs for 28 patients using polyvinyl siloxane. Clinical fit of the framework as a whole and of each retainer separately were evaluated by calibrated supervisors during framework try-in before (first evaluation) and after (second evaluation) possible adjustments (score 0 = poor fit, up to score 3 = good fit). Framework fit and fit of the denture base were evaluated at delivery (third evaluation). Finally, postinsertion sessions were evaluated and total number of sessions needed, sore spots, adjustments to the denture base, and reported food-impaction were recorded. RESULTS: No significant differences in clinical fit (of the framework as a whole, for the retainers, or for the denture base) were found between the groups in the three evaluation sessions. Differences were not found for postinsertion sessions with one exception: in the alginate group, four subjects reported food impaction, versus none in the polyvinyl siloxane group. CONCLUSION: Clinical fit of metal-frame PRDPs based on impressions with custom trays combined with alginate or polyvinyl siloxane was similar.

Alginatos/química , Materiais para Moldagem Odontológica/química , Técnica de Moldagem Odontológica , Modelos Dentários , Prótese Parcial Removível , Polivinil/química , Ajuste de Prótese , Siloxanas/química , Planejamento de Dentadura , Humanos , Estudos Prospectivos
Eur J Paediatr Dent ; 17(3): 223-226, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27759412


AIM: This in vitro study compares a new system for manual chair side fabrication of indirect composite restorations, which uses silicone models after alginate impressions, to CAD/CAM-technology and laboratory manual production techniques. MATRIALS AND METHODS: and study design Each 10 composite inlays were fabricated using different types of production techniques: CAD/CAM- technology (A), the new inlay system (B), plaster model after alginate impression (C) or silicone impression (D). The inlays were adapted into a metal tooth and silicone replicas of the cement gaps were made and measured. Statistical analysis was performed using ANOVA and Tukey's test. Results and Statistics In group A the biggest marginal gaps (174.9µm ± 106.2µm) were found. In group B the gaps were significantly smaller (119.5 µm ± 90.6 µm) than in group A (p=0.035). Between groups C (64.6 µm ± 68.0µm) and D (58.2 µm ± 61.7 µm) no significant differences could be found (p=0.998), but the gaps were significantly smaller compared with group B. Conclusion Chairside manufacturing of composite inlays resulted in better marginal precision than CAD/CAM technology. In comparison to build restorations in a laboratory, the new system is a timesaving and inexpensive alternative. Nevertheless, production of indirect composite restorations in the dental laboratory showed the highest precision.

Resinas Compostas/química , Adaptação Marginal Dentária , Materiais Dentários/química , Planejamento de Prótese Dentária , Restaurações Intracoronárias , Alginatos/química , Sulfato de Cálcio/química , Desenho Assistido por Computador , Materiais para Moldagem Odontológica/química , Modelos Dentários , Humanos , Teste de Materiais , Técnicas de Réplica , Silicones/química , Propriedades de Superfície
Am J Orthod Dentofacial Orthop ; 150(2): 261-7, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27476358


INTRODUCTION: The aim of this crossover study was to assess perceptions and preferences for impression techniques in young orthodontic patients receiving alginate and 2 different digital impressions. METHODS: Thirty-eight subjects aged 10 to 17 years requiring impressions for orthodontic treatment were randomly allocated to 3 groups that differed in the order that an alginate impressions and 2 different intraoral scanning procedures were administered. After each procedure, the patients were asked to score their perceptions on a 5-point Likert scale for gag reflex, queasiness, difficulty to breathe, uncomfortable feeling, perception of the scanning time, state of anxiety, and use of a powder, and to select the preferred impression system. Chairside time and maximal mouth opening were also registered. RESULTS: More queasiness (P = 0.00) and discomfort (P = 0.02) during alginate impression taking of the maxilla were perceived compared with the scans with the CEREC Omnicam (Sirona Dental Systems, Bensheim, Germany). There were no significant differences in perceptions between the alginate impressions and the Lava C.O.S. (3M ESPE, St Paul, Minn) and between the 2 scanners. Chairside times for the alginate impressions (9.7 ± 1.8 minutes) and the CEREC Omnicam (10.7 ± 1.8 minutes) were significantly lower (P <0.001) than for the Lava C.O.S. (17.8 ± 4.0 minutes). Digital impressions were favored by 51% of the subjects, whereas 29% chose alginate impressions, and 20% had no preference. Regardless of the significant differences in the registered times among the 3 impression-taking methods, the distributions of the Likert scores of time perception and maximal mouth opening were similar in all 3 groups. CONCLUSIONS: Young orthodontic patients preferred the digital impression techniques over the alginate method, although alginate impressions required the shortest chairside time.

Desenho Assistido por Computador , Técnica de Moldagem Odontológica , Preferência do Paciente , Percepção do Tempo , Adolescente , Alginatos , Criança , Estudos Cross-Over , Materiais para Moldagem Odontológica , Modelos Dentários , Feminino , Humanos , Masculino , Ortodontia