There are four types of direct esthetic
restorative materials currently in use. They are:
Composites are dominating the materials used for direct esthetic restorations. Glass ionomers are primarily used for restorations of cervical eroded areas. Hybrid ionomers provide better esthetics than glass ionomers. Compomers provide improved handling and fluoride release when compared with composites.
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| Permlastic is a polysulfide, condensation-cured, elastomeric impression material in three viscosities |
The custom trays also known as special trays are fabricated so that the final impression of the patient’s edentulous mouth can be taken accurately with proper border extension. The selective pressure technique helps in making the impression in such a way that when the newly fabricated dentures are worn by a patient, they exert pressure only on those areas of the mouth that can withstand the masticatory load. The selective pressure technique of impression making spares the non-pressure bearing area of the edentulous jaw and thus eliminate the possibility of trauma resulting in pain and ulceration in the mucosa. The special tray for selective pressure technique is made on the primary cast that has been prepared by pouring the impression made in alginate or impression compound. The impression taken in impression compound records the mucosa in a compressed state whereas the impression taken with alginate records the mucosa in a non-compressed state. From these two opposite states of mucosa record, a dentist proceeds to prepare a special tray that is used to make an impression with selective pressure. We will learn here as to how to make a special tray on a cast that has been made from impression compound.
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| Distribution of subject wise questions in NEET MDS examination. |
The harmful effects of the excessive dose of the ionizing radiation can be divided into two types. These are as follows:
We shall discuss them one by one in detail.
In earlier articles on radiography, you studied the effects of ionizing radiation on biological tissues. These effects can be divided into two types- Deterministic and Stochastic. Therefore, the radiation safety becomes of paramount importance white taking a radiograph.
In this article termed as radiation physics, we shall talk about the ways, the x-rays are produced, the events that occur at atomic level during their production and how can one save oneself and others.
Electrons that travel from the filament to the tungsten convert part of their kinetic energy into x-ray photons. This phenomenon occurs by the formation of bremsstrahlung and characteristic radiation.
Radiation biology is the study of effects of ionizing radiation on living systems. In this article we shall talk about the harmful effects of ionizing radiation on tissues, how does it occur, and how sensitive different types of cells are?
The effects of radiation on the tissues can be divided into 2 broad categories. The Deterministic and Stochastic effects.
Odontogenic Cysts
Nonodontogenic Cysts
Pseudocysts