ABSTRACT
PURPOSE: This study aimed to assess the reliability of the preoperative occlusal matrix technique in terms of the surface Vickers microhardness (VMH) of the underlying composite restorative material. MATERIALS AND METHODS: Two hundred microhybrid composite cylinders were built up and light-cured in a single-layer step, forming two experimental groups (N = 100) according to their heights (1.5 mm/2 mm). Each group was divided into five subgroups (N = 20) depending on the matrix thickness (no matrix/0.5 mm/1 mm/2 mm/3 mm). Half the specimens per subgroup (N = 10) were randomly polymerized with a quartz-tungsten-halogen (QTH) light-curing unit (LCU). The remaining half were cured using a light-emitting diode lamp. The top and bottom samples' sides were tested for VMH at 1 hour and 24 hours post-curing using a universal VMH machine. A multiple analysis of variance with repeated measurements for the "surface" factor and the Student-Newman-Keuls test were run (α = 0.05). Bottom/top microhardness ratios were compared with the empirically accepted limit (0.8). Surface topography was analyzed under a scanning electron microscope. RESULTS: The thinnest matrices provided the significantly best VMH values. LCU, disc height, and time also contributed to VMH. At 24 hours, 2-mm high discs polymerized with QTH resulted in inadequate microhardness ratios when 1-mm thick to 3-mm thick matrices were used. CONCLUSION: The thinnest matrices are the most recommendable ones. CLINICAL SIGNIFICANCE: The esthetics and occlusal reproducibility achieved with customized occlusal matrices fabricated before cavity preparation have been widely demonstrated. However, their effect on the physical properties of the restorations deserves further investigation. Although more studies are necessary, the thinnest matrices seem to be the most suitable to preserve the composite surface VMH and the curing depth.
Subject(s)
Composite Resins , Curing Lights, Dental , Hardness Tests , Humans , Microscopy, Electron, Scanning , Polymerization , Preoperative Period , Surface PropertiesABSTRACT
En el presente estudio, se describe la sistemática seguida por los dos principales sistemas presentes en España de procesado informático de la información que nos ofrece la tomografía computerizada (TC), para posteriormente, llevarla al acto quirúrgico mediante prototipado de guías quirúrgicas (estos sistemas son Nobel guide, Nobel Biocare y Facilitate, Astra Tech). También se hace una revisión de diferentes estudios que hablan sobre este tipo de sistemas, tratando el tema de su precisión y fiabilidad, sus indicaciones y sus limitaciones. Ante los datos obtenidos, podemos decir que dichos sistemas pueden ser divididos en tres apartados:1- Planificación óptima de la cirugía de implantes, teniendo en cuenta los ideales protésicos.2- Posibilidad de transferir dicha planificación al acto quirúrgico con gran precisión sin necesidad de realizar colgajo, gracias al prototipado de guíasquirúrgicas.3- Posibilidad de realizar carga inmediata en el mismo acto quirúrgico gracias a la exactitud que nos brinda el sistema. En cuanto a su precisión, podemos decir que es muy buena, pero se debe mejorar en la estabilidad de la guía quirúrgica durante la cirugía, y son necesarios más estudios para validar su exactitud (AU)
This study describes the systematics followed by the two principal data processing systems present in Spain offered by computerized tomography(CT) in order to later take it to surgical practice by means of prototyping surgical guides (these are the Nobelguide , Nobel Biocare and Facilitate, Astra Tech systems). A review is also made of different studies that report on this type of systems, dealing with the subject of their precision and reliability, their instructions and their limitations. In view of the data obtained, we can say that these systems can be divided into three sections:1- Optimal planning of the implant surgery, taking into account the prosthetic ideals.2- Possibility of transferring this planning to the surgical act with great precision without the need for making a flap, thanks to the prototyping of surgical guides.3- Possibility of performing immediate loading in the same surgical procedure thanks to the accuracy provided by the system. As regards its precision, we can say that it is very good, but the stability of the surgical guide during surgery should be improved, and further studies are necessary to validate its accuracy (AU)
Subject(s)
Humans , Dental Implantation/methods , Periodontal SplintsABSTRACT
Las benzodiacepinas son los fármacos psicotrópicos más prescritos en el Sistema Nacional de Salud. Las benzodiacepinas actúan amplificando las inhibiciones mediadas por el neurotransmisor GABA en el Sistema Nervioso Central, siendo el causante de los efectos clínicos de este grupo de fármacos, cuya eficacia y seguridad han sido sobradamente probadas. En Odontología, las benzodiacepinas son utilizadas en diversas actuaciones terapéuticas: sedación consciente, control de la ansiedad del paciente, relajación muscular producida por determinadas patologías, remisión de crisis comiciales, etc. Con el presente trabajo se pretende realizar una revisión y actualización del empleo que se hace de estos fármacos en el gabinete odontológico (AU)
Benzodiazepines are the most prescribed psychotropic drugs in the National Health System. Benzodiazepines act by amplifying the inhibitions mediated by the neurotransmitter GABA in the central nervous system, causing the clinical effects of this group of drugs whose efficacy and safety have been more than proven. In dentistry, benzodiazepines are used in different treatments: conscious sedation, control of patient anxiety, muscle relaxation produced by certain pathologies, seizure remission, etc. This paper attempts a review and updating of the use that is made of these drugs in the dental office (AU)