Moonlight is a 13 year old horse with bilateral sagittal factures of the upper 1st molars. Earlier attempts to extract these teeth orally were unsuccessful and the horse was referred to the Academy for surgical extraction. Partial removal of the crowns was accomplished during these attempts but the majority of the reserve crown and root still remained as shown in the lateral and dorsal ventral radiographs.
Oral extractions are difficult when the clinical crown is missing or fractured. In this case the adjacent teeth have drifted toward the fractured teeth filling in the space created by the missing portions of crown. This leaves the practitioner with a small clinical area in which to perform an oral extraction. Also complicating this extraction is the fact that feed has been packing into the fractured teeth causing periodontal disease which is a painful condition for the horse. Moonlight was not cooperative with any handling of this region by the practitioners. Sedation did not seem to be effective for further evaluation of the fractured teeth. A bilateral maxillary nerve block was performed along with local infusion of lidocaine on the buccal side of the fractured teeth. Moonlight’s pain was relieved and he was very cooperative for the ensuing procedures.
Surgical extraction is a reasonable option for this case but it was decided against due to the large size of this horse (1500 lbs.) and the amount of surgical time required for bilateral extractions, which can lead to complications during recovery. With the effectiveness of the local anesthesia, we felt that oral extractions could be successful in this case.
Because the crowns were fractured and partially missing, we decided to section the remaining portion of the crown and roots by making a cross cut from the buccal to the palatal side with a side-cut drill bit in a hand piece with a 90 degree head. This is a precise procedure that requires radiographs in order to measure the length of the reserve crown and roots that are to be sectioned. It is important to only section the tooth and not to cut into the alveolar bone. Sectioning of the tooth creates a space between the roots which allows instrument placement and manipulation of the separate fragments. It is important to properly elevate around the individual roots by placing the elevators between the roots and the alveolar bone. Using the bone as a fulcrum, we were able to extract the individual fragments successfully.
Discussion: Sagittal factures of the upper cheek teeth are thought to occur from weakened infundibula due to decay and erosion of the internal cementum. The most commonly affected teeth are the upper 1st molars. Genetics may also play a role since this is often a bilateral condition. Oral extraction of these types of fractured teeth is indeed a challenge for the oral practitioner and requires team effort. Proper instrumentation, digital radiographs, and effective nerve blocks are a necessity before attempting these complicated extractions on a standing horse.