Optical impressions assessment for overlay restorations with rubber dam: A clinical trial.

OBJECTIVE: The possibility of making impressions of teeth prepared with a rubber dam in place has been proposed; however, this requires trimming and rescanning the mesh, which has been described as a cause of accuracy loss. This study aims to clinically determine whether overlay restorations obtained from a scan with a rubber dam in place have equivalent marginal fit, contact points, and occlusal fit to the same type of restorations obtained from a scan without a rubber dam. MATERIAL AND METHODS: Thirty patients who underwent overlay restoration of a molar with at least one neighbouring tooth were selected. After tooth preparation, two scans were performed: one without a rubber dam and the other with a rubber dam. Restorations were randomly created from one scan or another. The marginal fit, interproximal contact points, and occlusal fit were evaluated clinically. Two meshes, with and without rubber dams, were also compared. RESULTS: No significant differences were observed in the clinical evaluation of the overlays made of the two meshes. The trueness of the mesh from the impression made with a rubber dam with respect to the mesh without a rubber dam was about 40 µm in the critical areas of the preparation (margins, intaglio, and interproximal contact points). CONCLUSIONS: The results of this study show that under the conditions performed and with the equipment used, there are no significant clinical differences between overlay restorations made from a scan with a rubber dam and those made from a scan without a rubber dam. CLINICAL SIGNIFICANCE: Scanning with a rubber dam in place may be a valid option for certain types of restorations under certain clinical conditions.

Evaluación in vitro mediante microscopíaelectrónica de barrido de la oclusiónde túbulos dentinarios de dos agentesdesensibilizantes / No disponible

Introducción: La sensibilidad dentinaria es un motivo de consulta frecuente y los tratamientos disponibles no siempre ofrecen resultados satisfactorios a largo plazo. De aquí surge la necesidad de buscar nuevas alternativas de tratamiento. Objetivos: Evaluar mediante microscopio electrónico de barrido la capacidad de oclusión de los túbulos dentinarios de dos agentes desensibilizantes comercializados compuestos por carbonato y fosfato potásico y cloruro de estroncio y de calcio (TwinGel) y por fluoruro de estaño (Emoflúor).Material y métodos: Se seleccionaron 15 dientes de origen humano y se cortaron 2 discos de dentina de cada diente. Se grabó la superficie dentinaria con ácido ortofosfórico durante 70 segundos y se dividieron los discos en 2 grupos. Al primer grupo se le aplicó el agente desensibilizante compuesto por carbonato y fosfato potásico, cloruro de estroncio y de calcio y al segundo grupo fluoruro de estaño, ambos durante 3 minutos. Posteriormente se observó con microscopía electrónica de barrido la oclusión de los túbulos dentinarios y se realizaron fotografías a 10.000 aumentos. El porcentaje de obturación tubular fue analizado mediante escala visual analógica. Resultados: Para el grupo 1 (Twin Gel) obtuvimos un promedio de oclusión de los túbulos del 73%, y para el grupo 2 (Emofluor) un62%, tras aplicar el agente desensibilizante durante 3 minutos. Discusión y conclusiones: Ambos tienen capacidad para ocluirlos túbulos dentinarios, sin embargo, la aplicación del producto desensibilizante Twin Gel sobre la superficie de dentina produce la oclusión de más de 2/3 partes de la superficie a tratar (AU)

Introduction: Dentinal sensitivity is a common problem. Although there have been described several treatments for this particular entity, none of them has offered the right solution for an extended period of time; for this reason, it is necessary to find new treatment alternatives. Aim: To evaluate the occlusion of dentinal tubules with two desensitizing agents “Twin Gel” (potassium carbonate and phosphate, strontium and calcium chloride) and “Emoflúor” (stannous chloride)using Scanning electron microscopy (SEM).Material and methods: 15 human teeth free of caries and restorations were used in this study. Two discs of each tooth were obtained and etched with ortophosphoric acid 37%. Discs were divided in2 groups. In the first group, a desensitizing agent with potassium carbonate, phosphate and strontium and calcium chloride was applied; in the second group, stannous chloride was used, both for 3minutes. Then, the occlusion of dentinal tubules was observed using SEM at 10.000 X. Percentages of tubular sealing were measured using a analogical visual scale. Results: For the group 1 (Twin Gel), an average of 73% of sealed tubuleswas observed, for the group 2 (Emofluor) a 63% was observed after application of desensitizing agent for 3 minutes. Conclusion: Both desensitizing agents have sealing capacity of dentinal tubules; however, the application of the “TwinGel” desensitizing agent on dentin surface, has an increased capacity of more than 2/3 parts of the treated surface (AU)

Estudio de la microfiltración en tres sistemas diferentes de elementos sobre implantes / No disponible

Los objetivos de este estudio in vitro son evaluar la presencia de gapsy microfiltración entre pilar e implante en un pilar cementado, pilar mecanizado, pilar colado en titanio, pilar colado en oro y pilar colado con conexión amortiguada, todos ellos excepto el primero, atornillados. Para ello se analizaron al microscopio electrónico, posteriormente se termociclaron y se realizó un análisis de filtración de fluidos. Los pilares cementados no fue posible valorar el gap, en los mecanizados el gap fue inexistente, en los colados en titanio fue de39.26 micras de media, en los colados en oro fue de 9.85 micras, en los colados en titanio amortiguados fue de 22.8 micras. Los pilares cementados, los mecanizados y los colados en titanio amortiguados no mostraron filtración, mientras que los pilares colados en titanio yen oro mostraron filtración de fluidos (AU)

The purpose of this in vitro study is to quantify the gap and microleakage in implants with trasmucosal collar and cemented bolt abutment, implants with screw retained prosthesis with mechanized abutment, implants with screw retained prostheses with abutment casted in titanium, implants with screw retained prostheses with abutment casted in gold and implants with transmucosal collar, resino'ring and titanium casted abutment will be used. All implants were analysed under a scanning electron, later we thermocycled its and evaluate fluid filtration. In mechanised abutments a mean of 0micron gap, in titanium casted abutments a mean of 39 micron gap,in gold casted abutment a mean of 22 micron gap, in casted abutment with o'ring a mean of 9 micron gap, and in cemented abutments the gap was completely filled with cement. Mechanised, cemented abutments and casted abutments with resin o'ring offer better results relating to abutment-implant interface sealing (AU)

Prótesis implantosoportada totalmentecerámica / No disponible

Objetivos: Evaluar la estética, la resistencia a la fractura y el ajuste marginal de los tratamientos restauradores cerámicos libres de metal. Material y métodos: Realizamos una búsqueda en PubMed/Medline. Resultados-Discusión: Diversos estudios clínicos demuestran que las restauraciones totalmente cerámicas ofrecen resultados estéticos excelentes y un éxito a largo plazo. Por otra parte, las coronas cerámicas libres de metal confirman tener una resistencia a la fractura menor que las restauraciones de metal-cerámica con aditamentos de titanio, aunque se ha comprobado que coronas de Empress 2,InCeram y AllCeram sobre aditamentos de cerámica funcionan satisfactoriamente en región de incisivos y premolares. En cuanto al ajuste marginal se vio que Procera presentaba el mejor ajuste marginal antes y después de la cementación en comparación con Empress2 e InCeram, independientemente de la combinación entre las líneas de terminación y los cementos probados. Tras la comparación de los aditamentos de titanio con los cerámicos se vio que los cerámicos ofrecen buenos resultados estéticos y funcionales a largo plazo. Conclusión: Se necesitan estudios a largo plazo para poder recomendar de forma rutinaria las cerámicas libres de metal (CLM), aunque los resultados actuales son prometedores (AU)

Purpose: Evaluation of the esthetics, fracture resistance and marginal fit of free metal restorations. Materials and methods: We carried out a search in PubMed/Medline. Results- Discussion: Several clinical studies demonstrated that all ceramic restorations achieved excellent esthetic results and a longterm success. On the other hand, free metal crowns (FMC) confirmed to have less fracture resistance than metal-ceramic crowns with titanium abutments, even though Empress 2, InCeram and AllCeramcrowns on ceramic abutments were proved to work satisfactorily in incisive and premolar regions. As regards marginal fit Procera showed the best marginal fit before and after cementation in comparison to Empress2 and InCeram. After comparing titanium abutments with ceramic abutments we noticed that ceramic abutments achieved good and long term esthetic and functional results. Conclusion: Although current results are promising, long term studies are required in order to be able to recommend FMC in a routine way (AU)