GTR

(guided tissue regeneration) Your teeth are at risk because of periodontal disease. Plaque and tartar on your teeth resulting from insufficient brushing and flossing can build up over time and lead to the loss of the supporting tissue around some of your teeth.
Found on http://www.dentalfind.com/info/gtr-guided-tissue-regeneration

gtr

Got to run
Found on http://www.noslang.com/dictionary/g/
No exact match found