Case History:A 3-year-old QH gelding in good condition has a history of a chronic draining tract under the 306. After a thorough oral examination and careful review of the radiographs it was apparent the 306 was infected. There was a periodontal pocket on the lingual side of the 306 which was discovered during the oral exam.
A root canal is not an option in this case because of the age of the tooth and the communication of the oral cavity and drain tract. Extraction is the only treatment for this case.
The mandibular cheek teeth do not have true infundibula as do maxillary cheek teeth, but rather enamel folds, which are not completely closed. The enamel ridges are surrounded by cementum which fills in these folds. Cementoblast which are located in the periodontal space, deposit cementum around the tooth during maturation and eruption. In this case there was incomplete cementum deposit which normally fills in the enamel folds, which allowed feed from the oral cavity to travel through the periodontal space of the tooth into the apical portion, causing a pulp infection and resulting drain tract.
B. W. Fletcher, DVM