Static and dynamic evaluations of the wettability of commercial vinyl polysiloxane impression materials for artificial saliva.

This study evaluated the wettability of commercial vinyl polysiloxane impression materials by measuring contact angles on horizontal and non-horizontal surfaces using artificial saliva. Three light bodies (Affinis [Affi], Silagum [Sila] and Variotime [Vario-LB]) and one extra light body (Viriotime [Vario-ELB]) were prepared with flat surfaces. Static and dynamic contact angles were measured using the sessile drop method as a function of time. Contact angle hysteresis was the value of advancing contact angle minus receding contact angle. The results indicated that all materials were classified as hydrophilic materials. Vario-ELB and Affi showed better initial wettability than the other two materials. Vario-ELB showed more hydrophilic properties and was more vulnerable to changes in the intraoral environment compared to Affi, Sila and Vario-LB. These results suggest that measuring the time-dependent dynamic contact angle on the inclined surface can provide effective information regarding the wettability of impression materials to evaluate their clinical performance.

Performance of dental impression materials: Benchmarking of materials and techniques by three-dimensional analysis.

Among other factors, the precision of dental impressions is an important and determining factor for the fit of dental restorations. The aim of this study was to examine the three-dimensional (3D) precision of gypsum dies made using a range of impression techniques and materials. Ten impressions of a steel canine were fabricated for each of the 24 material-method-combinations and poured with type 4 die stone. The dies were optically digitized, aligned to the CAD model of the steel canine, and 3D differences were calculated. The results were statistically analyzed using one-way analysis of variance. Depending on material and impression technique, the mean values had a range between +10.9/-10.0 µm (SD 2.8/2.3) and +16.5/-23.5 µm (SD 11.8/18.8). Qualitative analysis using colorcoded graphs showed a characteristic location of deviations for different impression techniques. Three-dimensional analysis provided a comprehensive picture of the achievable precision. Processing aspects and impression technique were of significant influence.

Linear dimensional stability of irreversible hydrocolloid materials over time

El objetivo de este estudio fue evaluar la estabilidad dimensional lineal de diferentes hidrocoloides irreversibles enfunción del tiempo. Se confeccionó una matriz metálica con sus correspondientes cubetas individuales realizadas con láminas termoplásticas (Sabilex, de 0.125 mm de espesor). Sele realizaron perforaciones para la retención del material. Se tomaron cinco impresiones con cada material a esta matriz, utilizando Kromopan 100 (LASCOD) [AlKr], que presentauna estabilidad dimensional de 100 horas, y Phase Plus (ZHERMACK) [AlPh], que tiene una estabilidad dimensional de 48 horas. Luego se tomaron fotografías estandarizadas adiferentes intervalos de tiempo (0, 15, 30, 45, 60, 120 minutos; 12, 24 y 96 horas), usando un dispositivo ad-hoc. Las imágenes se analizaron con software de procesamiento de imágenes(UTHSCSA Image Tool) realizando la medición de la distancia entre las intersecciones de surcos previamente realizados en la porción superior de la matriz. Los resultados obtenidos fueronanalizados mediante Análisis de Varianza para mediciones repetidas. Se detallan los datos iniciales y finales obtenidos (media y DS): AlKr: 16,44 (0,22) y 16,34 (0,11), AlPh: 16,40(0,06) y 16,18 (0,06). El análisis estadístico ha mostrado el efecto significativo para las variables material y tiempo. Bajo las condiciones de este estudio podemos concluir que tiempoafectaría significativamente la estabilidad dimensional lineal de los hidrocoloides irreversibles...

A novel technique to record crown and bridge impressions consistently.

Achieving accurate impressions of crown and bridge preparations remains a challenge for practicing dentists despite numerous material and technique advances. Precise material placement around the prepared tooth, proper management of soft tissue, and timely dispensing of both wash and tray materials are among the difficulties. As demonstrated in two cases presented, a new pneumatic impression device has been developed as a means of enabling clinicians to create precision impressions more easily, without the need for retraction cord or retraction paste.

Effect of different impression techniques on the dimensional accuracy of impressions using various elastomeric impression materials: an in vitro study.

UNLABELLED: Production of exemplary crowns and fixed partial dentures depends upon the usage of impression material and its technique of usage that accurately reproduces prepared teeth and their relationship to the adjacent oral structure. AIM: To evaluate the linear dimensional accuracy of the elastomeric impressions using various impression techniques using different combinations of viscosities of impression materials. MATERIALS AND METHODS: Crown preparation was done in a dentulous acrylic resin denture base model with six natural teeth embedded into it was made to represent the dentulous maxillary arch. A total of 55 impressions were obtained and poured in die stone using various impression techniques with different combinations of viscosities of impression materials. RESULTS: Among the six techniques used, the heavy body light body two-step technique using custom tray showed the least distortion which was closely followed by the putty wash two-step technique with 2 mm spacer using stock tray. CONCLUSION: The study revealed that the heavy body light body two-step technique with custom tray provided the best results. CLINICAL SIGNIFICANCE: Dimensional accuracy of impressions is very much required for precisely fitting of prosthesis. This study may be helpful to select the technique and materials as per clinical requirement of accuracy of impressions.

Design of removable partial dentures: a survey of dental laboratories in Greece.

The aim of this study was to compare data on design and fabrication methods of removable partial dentures (RPDs) in two major cities in Greece. A questionnaire was sent to 150 randomly selected dental technicians. The participation rate was 79.3%. The anterior palatal strap, the lingual bar, and the Roach-type clasp arm designs were preferred. Half of the RPDs fabricated were retained using precision attachments. Differences between the two cities were observed in types of major maxillary connectors used, types of attachments and impression materials used, as well as the design of distal-extension RPDs. Postdoctoral education was found to have an impact on RPD fabrication. Despite the differences observed, design and fabrication of RPDs followed commonly used principles.

Transferencia de la posición tridimensional del implante / Transfer of the three-dimensional implant position

Uno de los pasos fundamentales para la obtención de un resultado protésico satisfactorio en implantología es la transferencia de la posición tridimensional del implante ya oseointegrado al modelo definitivo. Para ello generalmente se utilizan cubetas individuales de termocurado confeccionadas por el protésico dental, rígidas y con perforaciones que corresponden a la emergencia del transfer del implante y materiales de tipo elastómeros. En el siguiente trabajo se expondrán los pasos detallados para una correcta toma de impresiones, la crítica de las mismas y la justificación de los materiales utilizados. Asimismo, se expondrán las bondades que presentan las placas de fotocurado para la realización de una cubeta individual por el profesional, confeccionadas a partir de un modelo de estudio preliminar, en el consultorio.

Impression materials in fixed prosthodontics: influence of choice on clinical procedure.

The purpose of this article is to review impression materials used for fabricating fixed restorations in dentistry. Their compositions, properties, advantages, and disadvantages are presented and compared. How these properties influence clinical decisions is also described. This review helps the clinician choose which material is more suitable for a specific case. A broad search of the published literature was performed using Medline to identify pertinent current articles. Textbooks, the Internet, and manufacturers' literature were also used to supplement this information. It is limited to impression materials used in fixed prosthodontics. The review gives basic knowledge of ideal impression material properties and discusses traditional and, primarily, more recently developed products, such as polyethers, poly(vinyl siloxane), polysulfides, and condensation silicone materials. Clear advantages and disadvantages for these impression materials are provided along with the role that compositional variations have on the outcome of the impression. This should enable clinicians and technicians to easily identify the important physical properties of each type of impression material and their primary clinical indications.

Linear dimensional stability of elastomeric impression materials over time

El objetivo del trabajo fue evaluar la estabilidad dimensional lineal de diferentes elastómeros para impresión. Se confeccionó una matriz metálica con sus correspondientes cubetas individuales realizadas con láminas termoplásticas (Marca Sabilex, de 0.125 mm de espesor). Se tomaron tres impresiones con cada material a estamatriz. Se utilizaron tres siliconas por adición: Examix-GC- (AdEx), Aquasil-Dentsply-(AdAq), y Panasil –Kettenbach-(AdPa); y tres siliconas por condensación: Densell-Dental Medrano-(CoDe), Speedex-Coltene-(CoSp), y Lastic-Kettenbach-(CoLa). Se realizaron todas las impresiones utilizando dos consistencias: pesada y liviana, con la técnica de un solo tiempo. Luego se tomaron fotografías estandarizadas a diferentes intervalos de tiempo (0, 15,30, 60, 120 minutos; 24 horas; 7 días y 14 días), con una cámara fotográfica digital, utilizando un dispositivo ad-hoc. Las imágenes se analizaron con software de procesamiento de imágenes (Image Tool) realizando la medición de la distancia entre las interseccionesde surcos previamente realizados en la porción superior de la matriz. Los resultados obtenidos fueron analizados mediante Análisis de varianza para mediciones repetidas. La media y el DSinicial y final para todos los materiales fue: AdEx: 1,32 (0,01) y 1,31 (0,00); AdAq: 1,32 (0,00) y 1,32 (0,00); AdPa: 1,327 (0,006) y 1,31 (0,00); CoDe: 1,32 (0,00) y 1,32 (0,01); CoSp: 1,327 (0,006) y 1,31 (0,00); CoLa: 1,327 (0,006) y 1,303 (0,006). La evaluaciónestadística mostró el efecto significativo de las variables material y tiempo. Conclusión: Bajo las condiciones de este estudio podemos concluir que el tiempo afectaría significativamente la estabilidad dimensional lineal de elastómeros para impresiones.

Dimensional accuracy of resultant casts made by a monophase, one-step and two-step, and a novel two-step putty/light-body impression technique: an in vitro study.

STATEMENT OF PROBLEM: Dimensional accuracy when making impressions is crucial to the quality of fixed prosthodontic treatment, and the impression technique is a critical factor affecting this accuracy. PURPOSE: The purpose of this in vitro study was to compare the dimensional accuracy of a monophase, 1- and 2-step putty/light-body, and a novel 2-step injection impression technique. MATERIAL AND METHODS: A stainless steel model with 2 abutment preparations was fabricated, and impressions were made 15 times with each technique. All impressions were made with an addition-reaction silicone impression material (Aquasil) and a stock perforated metal tray. The monophase impressions were made with regular body material. The 1-step putty/light-body impressions were made with simultaneous use of putty and light-body materials. The 2-step putty/light-body impressions were made with 2-mm-thick resin-prefabricated copings. The 2-step injection impressions were made with simultaneous use of putty and light-body materials. In this injection technique, after removing the preliminary impression, a hole was made through the polymerized material at each abutment edge, to coincide with holes present in the stock trays. Extra-light-body material was then added to the preliminary impression and further injected through the hole after reinsertion of the preliminary impression on the stainless steel model. The accuracy of the 4 different impression techniques was assessed by measuring 3 dimensions (intra- and interabutment) (5-mum accuracy) on stone casts poured from the impressions of the stainless steel model. The data were analyzed by 1-way ANOVA and Student-Newman-Keuls test (alpha=.05). RESULTS: The stone dies obtained with all the techniques had significantly larger dimensions as compared to those of the stainless steel model (P<.01). The order for highest to lowest deviation from the stainless steel model was: monophase, 1-step putty/light body, 2-step putty/light body, and 2-step injection. Significant differences among all of the groups for both absolute dimensions of the stone dies, and their percent deviations from the stainless steel model (P<.01), were noted. CONCLUSIONS: The 2-step putty/light-body and 2-step injection techniques were the most dimensionally accurate impression methods in terms of resultant casts.

Impresiones para el desdentado total: cubetas con topes digitales / Impressions for the complete edentulous patient: trays with digital tops

Las impresiones necesitan una distribución adecuada de los compuestos de impresión, para lo cual el mantenimiento de los dedos en la misma posición sobre la cubeta en las diferentes etapas, es fundamental. Se propone el agregado de topes que aseguren que la presión se realice siempre en el mismo lugar y que impidan el avance o el retroceso de los dedos sobre la cubeta. Se presentan las experiencias que justifican la propuesta.

Impresiones para el desdentado total: cubetas con topes digitales / Impressions for the complete edentulous patient: trays with digital tops

Las impresiones necesitan una distribución adecuada de los compuestos de impresión, para lo cual el mantenimiento de los dedos en la misma posición sobre la cubeta en las diferentes etapas, es fundamental. Se propone el agregado de topes que aseguren que la presión se realice siempre en el mismo lugar y que impidan el avance o el retroceso de los dedos sobre la cubeta. Se presentan las experiencias que justifican la propuesta.(AU)

Análisis de las técnicas de impresión en prótesis parcial removible a extensión distal / Analysis of the impression technique in distal extension removable partial denture

El procedimiento de impresión es una etapa importante en la elaboración de la prótesis parcial removible al reproducir la anatomía dentaria, los rebordes alveolares residuales y las estructuras adyacentes. La impresión funcional se indica para los casos dentomucosoportados para hacer compatible las diferencias en el comportamiento de los dientes pilares y la mucosa del reborde bajo cargas funcionales. Existen distintas técnicas de impresiones funcionales y todas ellas influyen distintamente en el desplazamiento de los tejidos que recubren al reborde y en el comportamiento de las bases protésicas. La técnica de modelo alterado es uno de los procedimientos de impresión más utilizados debido a los resultados que se obtienen, sin embargo, recientemente se ha demostrado efectos similares con otras técnicas.

The impression procedure is an important step in achieving sucess in removable partial denture. The functional impression is used for tooth-mucosa supported removable partial denture and it´s an attempt to accommodate the difference in resiliency between hard and soft tissue support. There are many techniques and all of them displace residual ridge mucosa in different ways. The altered cast impression fulfills the requirements of functional impression, however, other techniques have demonstrated the same effects.