Category: R

A prosthesis used during radiation treatment that protects adjacent areas of tissue not meant to be radiated from ortho‐voltage during treatment of malignant lesions of the head and neck area. Also known as a radiation positioner.  

In dentistry, usually refers to ionizing radiation. The energy that comes from a source of unstable atoms, which have excess energy, is then passed through tissue, producing charged particles called ions. These unstable ions are radioactive and become stable by release of energy, which can be in the form of electromagnetic radiation, such as X‐rays,…

Radiation absorbed dose, a unit of absorbed dose of ionizing radiation equivalent to an energy of 100 ergs per gram of irradiated material. A unit of measurement of absorbed radiation dose.  

The maximum peak‐to‐valley height of the entire measurement trace.  

The arithmetic average of the absolute value of all points of the profile, also called central line average height.  

A two‐dimensional roughness parameter calculated from the experimental profiles after filtering.  

The distance from a fixed reference point on a tooth or stent to the tip of the periodontal probe during usual periodontal diagnostic probing.  

A condition in which one or more forms of periodontitis are unresponsive to treatment despite excellent patient compliance and delivery of periodontal therapy that ordinarily is successful in arresting the progression of periodontitis.  

A condition in which periodontitis has been successfully treated but then recurs.  

A previously used term.