orthodontics: dental specialty that using braces, retainers, and other dental devices to treat misalignment of teeth, restoring them to proper functioning. orthodontist: the oral health provider who specializes in diagnosis, prevention, interception, and treatment of malocclusions, or bad bites, of the teeth and surrounding structures.
Define metric system: a decimal system of weights and measures based on the meter and on the kilogram a decimal system of weights and measures based on the meter and on the kilogramâ¦ See the full definition
1 The unit of mass is the kilogram. 2  A kilogram (kg) weighs the same as a litre of water (at normal temperature, and pressure). 3  1 gram (g) is the weight of 1 millilitre of water at 0 degrees Celsius. 4  The metric tonne is 1000 kilograms or a million grams.