RESTS AND REST SEATS

Rest: A rigid component of a removable partial denture which rests in a recessed preparation on the occlusal, lingual or incisal surface of a tooth to provide vertical support for the denture. Although a rest is a component of a direct retainer (retentive unit, clasp assembly), the rest itself is classified as a supporting element due to the nature of its function.

Determination of Melting points and Boiling points

The melting point (m.p)℃ of a compound is the temperature at which it changes from a solid to a liquid. Since this requires that the intermolecular forces that hold the solid together have to be overcome . The melting point is a physical property (melting point, boiling point, density, solubility ,etc.) often used to identify compounds . Usually, chemists can only obtain a melting range of a 2 - 3℃ accuracy. A pure, non-ionic, crystalline organic compound usually has a sharp and characteristic melting point (usually 0.5-1.0 ℃ range).

Surveying

This objective is achieved by a careful evaluation of a patient’s study casts. The instrument used to aid the examination of the study casts is called a dental surveyor and the procedure is known as surveying.