Diamond burs are generally used for reducing tooth structures to prepare cavities for restorations or place crowns or porcelain veneers. Diamonds may also be used to smooth, refine, and polish composite or porcelain material.
Tooth Whitening
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| Photograph showing before and and after teeth whitening procedure. |
Tooth whitening is done to correct the discoloration of a tooth. When we talk about discoloration of a tooth, we mean to say that the color of a tooth has changed from its normal white color to light yellow, yellow, light brown to dark brown or from light grey to dark grey or to complete black. The discolouration may be of one tooth or all the teeth may be discoloured. Discoloration of a tooth is caused by several factors. It may be due to deposition of external stains over the surfaces of a tooth or it may be because of the internal position of certain chemicals into the teeth structure at molecular level during the period when teeth were being formed in the mother’s womb.
Composites: Composition
Composites are tooth coloured restorative materials that are usually recommended for class III, IV and class I cavities with less or no occlusal stress and esthetics are important. Specially designed composites are used in almost 50% of class II restorations, although less durable in comparison to dental amalgam. Composites can be classified as microfilled, nanofilled, flowable, packable, all purpose and laboratory. Composites are used for provisional restorations and core build-ups and in fibre-reinforced posts.
Composites: Properties
You have read about the composition of dental composites in earlier class notes This article will speak about the properties.
Properties of Composites
The important properties of the composites are as follows:
- Polymerisation shrinkage - should be low
- Water sorption - should be low
- Coefficient of thermal expansion - should be same as tooth
- Fracture resistance - should be high
- Wear resistance - should be high
- Radiopacity- should be high
- Bond strength to enamel & dentin - should be high
- Colour match to tooth structure - should be excellent
- Manipulation - should be easy
- Finishing and polishing - should be easy
Few of the above mentioned properties may be important for anterior than posteriors restorations and vice versa. The properties of
microfilled and nanofilled composites are same while the microhybrid's differ from both of them.
Direct Esthetic Restorative Materials
Direct Esthetic Restorative Materials
There are four types of direct esthetic
restorative materials currently in use. They are:
- Composites
- Compomers
- Hybrid
Ionomers
- Glass Ionomers
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.
Polysulfide Impression Materials
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| Permlastic is a polysulfide, condensation-cured, elastomeric impression material in three viscosities |
Polysulfide impression materials are flexible but do not have the major changes in dimensions during storage like agar and alginate. Furthermore, the polysulfide impression is much stronger and more resistant to tearing than agar or alginate. It can be electroformed and therefore metal dies or models, in addition to gypsum models, can be prepared.
Non-carious loss of tooth structure
Types, clinical features, Causes prevention & treatment
Non-carious loss of tooth structure is a problem that is often found in senior citizens and is a cause of many complaints. It is not a new entity but has acquired more attention in recent time.
Types of tooth wear
- Abrasion
- Attrition
- Erosion
- Demastication
- Abfraction