An amalgam consists of a mixture of two or more metals, one of which is mercury. Dental amalgam consists, essentially, of mercury combined with a powdered silver-tin alloy. Mercury is a liquid at room temperature and is able to form a ‘workable’ mass when mixed with the alloy. This behaviour renders the material suitable for use in dentistry. Dental amalgam has been used for many years with a large measure of success. For many years it was the most widely used of all filling materials. For various reasons, including the development of viable alternatives based upon resins and ceramics and perceptions of a dubious and frequently questioned level of safety, its popularity has declined.

Many designs of cavity have been used for amalgam restorations, starting with modification of Black’s design for cavities for gold restorations. Over the years the cavity design has been refined to minimize destruction of sound tooth tissue and to give an appropriate form to the restoration to ensure that the physical properties of the material are optimized in the end product. Amalgam has no intrinsic ability to bond to enamel and dentine, hence cavities have to be used which are undercut, i.e., the cavity is wider within the structure of the tooth than at its surface, in order that the material should be mechanically retained. At all times the cavity should be no wider than is compatible with removal of caries from the dentine, removal of any unsupported enamel and adequate access to pack the amalgam into the cavity.

It is important when rebuilding the proximal surfaces of any tooth to restore its contact relationship with any adjacent tooth. Obviously the use of a matrix may compromise this objective as the thickness of the matrix is interposed between the filling material and the tooth. This problem is surmounted when using amalgam in two ways. First, having adapted the matrix to the tooth it is burnished outward to try to achieve a contact with the adjacent tooth. Second, a wooden or metal wedge should be inserted between the teeth if possible. This has a dual benefit in that it helps to maintain adaptation of the band to the tooth surface cervically and it separates the teeth slightly. Once the wedge is in place the matrix can be loosened slightly to facilitate burnishing against the adjacent tooth.

The work of dentist is to diagnose, treat and prevent problems related with mouth tissues and teeth. In addition, the dentist has several other duties such as removing decay, examining x-rays, repairing fractured teeth, filling cavities, straightening teeth, as well as insertion protective plastics sealants on the teeth of children. Other duties of dentist are to perform corrective surgery on the supporting bones and gums in order to treat diseases of the gum. If you have a missing tooth, it is the work of a dentist to extract teeth and make measurements for dentures in order to replace them.

In addition, other duties may include providing instructions on diet, flossing, brushing, the use of fluorides and several other aspects of dental care. In addition, dentists administer anesthetics and they are the ones who write prescriptions for medications and other such medications. There are several equipment which dentist use in their day-to-day activities such as the x ray machine, drills and several instruments like forceps, probes, mouth mirror, scalpels and brushes. As the dentist administers dental care, he/she wears masks, safety glasses and gloves that provide the necessary protection from several infectious diseases. This also helps the patient from getting these diseases.

Most of the dentists are general practitioners and they are the ones who handle a variety of dental needs. There are however nine specialty areas where dentist practice and these are: Orthodontist which is the largest group of specialty and their work involves straightening teeth by putting pressure to teeth with retainers or braces. Oral and maxillofacial who operates on the jaws and mouth. Periodontist who treat gum and the bones that support the teeth. Prosthodontist who replaces teeth with permanent fixtures, Endodontist, Public health dentist, Oral pathologist, Oral and maxillofacial radiologist.