Review of Surgical Extraction of Mandibular Cheek Teeth

Take Home Message—Successful surgical extraction of all mandibular cheek teeth is possible, and a variety of surgical approaches are available. Choosing an appropriate approach depends heavily on the experience of the surgeon, the condition of the tooth, and the clinical presentation of the horse.

I. Introduction

Pathology associated with equine cheek teeth has been well documented by many research veterinarians and scientists from around the world.¹ Dental fractures leading to significant crown loss and pulp exposure, apical infection, periodontal disease, dental malformation, supernumerary teeth, and maloccluded teeth are all potential pathologies that would necessitate extraction of a cheek tooth. Patient age and health, severity of disease, tooth positioning, severity of clinical signs, and owner’s financial and physical capabilities all play a role in determining if extraction is the best therapeutic option. Extraction of equine cheek teeth, especially of those that are not already mobile, is a demanding undertaking for both horse and veterinarian, and it should be undertaken with serious thought, preparation, and conviction. Before attempting any extraction proper sedation, anesthesia, analgesia, visualization, equipment, and assistant help should be ready for use. The surgeon undertaking the extraction should also be prepared to handle any complication that arises as a result of the procedure however minor or major.

In all published studies to date, intraoral extraction of teeth has provided the highest success rate and the lowest complication rate of any extraction technique; therefore, intraoral extraction of cheek teeth in the horse should always be considered prior to surgical extraction options.² When intraoral extraction is either impossible or suboptimal, surgical extraction techniques can be utilized. The fact that there are so many different approaches to the extraction of equine cheek teeth highlights that no one technique is appropriate for every case. The more techniques a surgeon masters, the more positive the outcome for the horse. The ideal surgical procedure is always the one that poses the least amount of risk for major complication and disturbs the least amount of soft and hard tissue while providing adequate visualization and access to perform the extraction. Indications for these procedures are loss or severe damage to clinical crown, crown-root fractures, apical infection of young teeth, impacted teeth, open-mouth restriction, very small patient size, radicular/odontogenic cyst formation, and dental malformation. The following extraction techniques have been previously described in the literature, and a summary of each technique is presented.

II. Materials and methods

**An in-depth knowledge of equine maxillofacial and dental anatomy is paramount to perform these surgical procedures successfully.**

All surgical descriptions are quoted directly from the articles indicated.

Immediate Pre-surgical Preparation:

• A complete oral exam was performed and intraoral dental treatments were performed as necessary.
• Preoperative radiographs were acquired to ensure the appropriate tooth for extraction and to evaluate regional and dental anatomy/pathology.
• Procedures were performed by either general anesthesia or standing with a CRI depending on the procedure and the disposition of the horse.
• The head was supported either by table or suspended with dental halter or like equipment.
• Sites were clipped and aseptically prepped.
• The site was draped, partially draped, or undraped depending on the technique.

Procedure A: Lateral Buccotomy Technique as described by O'Neil³

All performed under general anesthesia. 

• Pre-surgical Landmarks

1. The clinical crown and gingival margin of the tooth to be extracted.

2. The junction of the buccal mucosa and the alveolar mucosa (vestibule or buccal reflection) adjacent to the tooth extracted.

• Incision

1. The skin incision was centered directly over the tooth to be extracted.
2. Dorso-ventrally the incision was centered between the gingival margin and the buccal reflection (vestibule).
3. A 5-10 cm long skin incision directed ventrally approximately 30 degrees in a caudo-dorsal to rostro-ventral direction.
4. If parotid salivary duct in surgical field, it was either retracted or transected and subsequently repaired.

• Access to Tooth

1. Buccal part of buccinator muscle was incised.
2. Care was given to identify and avoid facial nerve.
3. Sharp and blunt dissection was performed through underlying connective tissue and glandular layer.
4. Buccal venous plexus was encountered deep to glandular tissue in caudal mandible resulting in significant bleeding. Electrocautery and ligation used for hemostasis.
5. Buccal mucosa was sharply incised, and the incision extended rostro-caudally to expose the full width of the clinical crown. Identity of tooth confirmed.
6. A dorso-ventral gingival incision made rostral and caudal to the affected tooth from the free gingival margin to the buccal reflection (vestibule).
7. Gingiva and mucosa elevated off tooth and lateral alveolar bone plate using periosteal elevator.
8. Bone plate partially removed by chiseling.

 

1. With part of reserve crown exposed, the periodontal ligament was broken down with use of small gouge around tooth edges in attempt to remove tooth en bloc.
2. Most teeth required splitting either longitudinally or latero-medially using a chisel and mallet and the tooth was removed piecemeal.

Procedure B: Transcortical Osteotomy and Buccotomy as described by Tremaine⁴

All teeth were impacted or partially erupted, and all procedures were performed under general anesthesia.

• Pre-surgical Landmarks

1. Using fluoroscopic guidance, the osteotomy site was marked with skin staples.

• Incision

1. A curvilinear skin incision was made with its base orientated coronally, so that skin reflection exposed tissues overlying the unerupted tooth. The buccinator muscle was bluntly sectioned, and the ventral branch of the facial nerve was identified and a traumatically reflected.
2. The periosteum was identified, incised, and reflected.

• Access to Tooth

1. Positioning confirmed by fluoroscopy and an osteotomy was made through mandibular cortex using a sharp osteotome or an air- powered bur parallel with the rostral margin of the apical component of the tooth.
2. A second parallel osteotomy was made 2 cm more caudal (level with the caudal extremity of the tooth) and was extended to the level of the gingival attachment to the bone at the gingival sulcus.
3. The buccal mucosa was sharply incised at its mucoperiosteal attachment.
4. The section of lateral mandibular cortex and dental alveolus was elevated in a coronal to apical direction to expose the unerupted tooth, until the remaining apical side of the cortical flap fractured and the bone was discarded. 
5. If needed, the osteotomy was enlarged with bone rongeurs or a sharp osteotome.

• Tooth Extraction

1. Periodontal ligaments around the dental apex and on the mesial and distal aspects were disrupted with a sharp elevator and a gouge.
2. The tooth was sectioned longitudinally or transversely using a bur or sharp chisel.
3. The apical dental fragments were separated and elevated through the osteotomy site and any coronal fragments were repulsed into the oral cavity if the path was unobstructed by adjacent teeth.

Procedure C: Transcutaneous Lateral Alveolar Ostectomy as described by Rawlinson5 as modified from Tremaine⁶

All performed with either standing sedation or under general anesthesia.

• Pre-surgical Landmarks

1. The junction of the buccal mucosa and the alveolar mucosa (vestibule) adjacent to the tooth to be extracted.
2. The clinical crown of the tooth to be extracted.

• Incision

1. The skin incision was placed directly over the tooth to be extracted.
2. Premolar: a curvilinear, horizontal incision extending in a rostrocaudal direction with the base oriented apically was created. The most ventral portion of the incision was placed directly over the tooth midway between the vestibule (previously marked) and the root apices of the tooth.  [...]