Oral Extraction of Cheek Teeth

Take Home Message—If feasible, oral extraction of cheek teeth is the preferred technique of exodontia in horses. It can be performed in standing sedated and locally anesthetized horses. Compared to other methods of exodontia, the post-operative complication rate is low.

I. Aim of the presentation

To describe how to perform oral extraction of equine cheek teeth.

II. Introduction

Oral extraction was described by Merillat already in 1906. Together with improved general anesthesia of equines, more invasive methods of tooth removal became increasingly popular.¹ Until the 1990’s, repulsion was the preferred method of exodontia for diseased equine cheek teeth. However, the complication rate of this technique was found to be considerably high^2,3 and lateral alveolar buccotomy was described as an alternative surgical method for extraction of the rostral three maxillary cheek teeth and rostral four mandibular cheek teeth with a lower complication rate.^4,5 The limits of lateral alveolar buccotomy have been described.⁶ More recently, lateral alveolar osteotomy has been utilized for surgical extraction of the caudal cheek teeth in both anesthetized and standing horses (Rawlinson, these proceedings).

III. Material and methods

Recommended Instruments for Oral Extraction of Cheek Teeth

• Flat-bladed elevator
• Set of molar separators/spreaders (2-3) of variable sizes and shapes
• Set of extraction forceps (serrated, 3-pronged, 4- pronged, fragment forceps...)
• Device for handle fixation (tape, rope, rubber band, bar clamps ...)
• Fulcrum with exchangeable heads of different sizes
• Set of root elevators, straight and curved
• Packing material for alveoli (gauze, dental impression material, bone cement, bone wax, plaster of paris.)

Extraction Technique –Step-by-Step

• Setup and Preparations Prior to Extraction
  The animal is sedated and anti-inflammatory premedication (flunixin-meglumine, 1.1 mg/kg i.v., b.i.d.) as well as antibiotic premedication (e.g. sodium penicillin, 30000 IU/kg i.v., q.i.d.; Gentamicin, 6.6 mg/kg i.v., s.i.d.) is administered via a venous indwelling catheter.

A local nerve block, depending on the location of the affected tooth, is performed (see in Proceedings: Local Anesthesia for Dental Procedures). Dental extraction is painful and should only be initiated when the local nerve block is fully effective. The required waiting time is 15-20 minutes. During this time the setup of all instruments can be completed or dental correction can be performed if needed.

A full mouth speculum is inserted and the oral cavity is rinsed with water. For the final flush a mild disinfectant (e.g. diluted (0.2-1 %) chlorhexidine solution,) might be used.

• Separation of the Gingival
  After identifying the correct tooth, the gingiva on both sides of the affected tooth is elevated using a flat-bladed elevator.
   
• Separation/Spreading of Interdental Spaces
  In a next step, the interdental spaces rostral and caudal of the affected tooth are widened using molar separators (spreaders).

Usually the spreaders are at first used on the rostral side of the tooth to be extracted; then the caudal interdental space is widened. When extracting a 3rd premolar (-07) the spreaders should be first inserted into the caudal interdental space. Care should be taken when using a spreader in the first or last interdental space as the -06 or -11 might be inadvertently loosened excessively.

Visual control of the correct positioning of the spreader blades on the buccal and palatial/lingual aspects of the respective interdental space should be performed before the blades are wedged between the teeth. Applying excessive force on the handles of spreaders in an incorrect position (on the sides of the tooth to be extracted or neighboring teeth) might result in dental fracture!

Spreading of the interdental space is a painful procedure which might provoke intense defensive movement of the horse. Consequently molar spreaders should first be applied when local anesthesia is fully effective.

If several pairs of molar spreaders are available, it is recommended to start with smaller wedged instruments. Subsequently larger sizes of spreaders might be used to further enlarge the interdental space(s).

Depending on the location, age and configuration of the tooth, widening of the interdental spaces might be accomplished within seconds or might require up to 20 minutes. Patience is required and strongly recommended for this essential step of oral cheek tooth extraction.

Sometimes soft tissues become entrapped between the blades of the spreader thus impeding complete closure of the blades in the interdental space. This problem can be overcome by removing the spreader, gentle flushing of the interdental space with water and repeating the procedure.

Sometimes the blades of the spreader are forced towards the occlusal surface during closure which renders spreading ineffective. To overcome this problem it might help to close the speculum to a degree which allows using the opposing cheek teeth row as a thrust block for the wedges of the instrument. In this way the undesirable effect of the wedges gliding out of the interdental space might be prevented.

• Placement of the Extraction Forceps
  Molar extraction forceps are available in a multitude of different sizes and shapes. No instrument is perfect for every tooth and over time the amount of available extraction forceps will increase in every dental practice.

Mandibular cheek teeth are narrower than their maxillary counterparts. Consequently forceps with different spacing between their jaws in closed position are required.¹ This is also true for dental extractions in

ponies and miniature breeds. In these patients small instruments with narrower spacing are required to successfully extract cheek teeth.

Before fixation of the handles, the position of the jaws of the extraction forceps on the crown should be controlled. The jaws should be firmly attached to the crown of the tooth to be extracted. Malpositioning of the jaws might involve a neighboring tooth, an interdental space or the bony alveolar crest of the mandible or maxilla.

At least minimal rotation can be provoked in any cheek tooth with correctly positioned extraction forceps, especially after spreading. This should be visualized closely.

Repositioning of the forceps ́ jaws is necessary when the tooth does not respond to horizontal movements of the forceps or if the jaws or prongs of the forceps glide on the buccal and/or lingual/palatinal surfaces of the dental crown. This frequently results in substantial abrasion of the dental crown and might ultimately render oral extraction impossible if the crown fractures.

• Fixation of the Extraction Forceps
  When the tooth to be extracted is not excessively loose, the handles of the forceps should be tightened and fixed. According to the surgeons preference, this can be performed with rope, rubber band, adhesive tape or a bar clamp to name the most frequently employed techniques. Some extraction forceps come with an implemented locking mechanism. However, those mechanisms might be potentially dangerous to the veterinarian or to assistants and viewers.
   
• Loosening of the Tooth With Extraction Forceps
  In the beginning the forceps are oscillated with low amplitude movements in the horizontal plane.¹ Rotating and twisting movements should be avoided as they might result in inadvertent abrasion or fracture of the clinical crown. Eventually the amplitude of the horizontal movements can be increased as the tooth loosens. Again, the premature increase of the amplitude or force of the horizontal oscillations might cause abrasion or fracture of the clinical crown.

Foamy hemorrhage from the periodontal space, typical “squelching” noises and a decreasing resistance of the periodontal ligament to the oscillating movements of the extraction forceps are typical signs for good progress in disrupting the periodontal attachments of the tooth. Sharp, cracking noises, followed by sudden loss of resistance towards the oscillations indicate dental or root fracture(s).  [...]