Extractions

Indications, Equipment, Complications and Techniques

Introduction

Tooth extraction is one of the most common surgical procedures performed by veterinarians in small animal practice and should be perfected by all who attempt it. I would like to think that the ideal tooth extraction is the removal of the complete tooth, or tooth root, with minimal trauma to the surrounding soft and hard tissues, that results in a wound that heals uneventfully and without complications. Tooth extraction requires the veterinarian to have a detailed knowledge of anatomy, suturing, dental materials and equipment relevant to the procedure, as well as technique to accomplish the procedure. Every veterinarian should endeavour to make every tooth extraction an ideal one.

Common indications for extractions

The decision to extract a tooth should be a co-operative one between the owner and the veterinarian, but ultimately guided by the veterinarian.

The most common indications for tooth extraction include:

1. Persistent deciduous teeth
2. Interceptive orthodontics / Malocclusions
3. Severe periodontal disease
4. Highly mobile teeth
5. Endodontic disease
6. Impacted teeth
7. Jaw fractures
8. Oral tumours
9. Severe disease or injury to the crown, neck or root of the tooth
10. Tooth resorption (previously termed feline odontoclastic resorptive lesions)
11. Supernumerary teeth

In veterinary dentistry, extraction is a common indication due to lack of skill or experience by the veterinarian to perform advanced or specialist procedures, lack of referral opportunity, or financial constraints of the pet owner.

The importance of a tooth, i.e. its strategic position and the function it has in the mouth are important factors that must be considered before extraction. The canine and carnassial teeth (maxillary fourth pre-molar and mandibular first molar) play an important function in the mouth. The maxillary canines prevent the lips falling into the mouth, whilst the mandibular canine aids in keeping the tongue in the mouth. When a pet loses a maxillary canine tooth, an ulcerated lip often results, as the lip comes in contact with the cusp of the mandibular canine tooth. When a pet loses the mandibular canine teeth, the tongue often falls out of the mouth, which can result in a dry, painful tongue surface. It has also been shown that significant resorption of the rostral mandible occurs, often resulting in a pathological fracture. The carnassials are important for the cutting of the diet into small bite size pieces prior to swallowing and if either of these are lost, significant plaque accumulation occurs on the opposite arcade carnassials tooth and subsequent periodontitis.

The number of pet’s teeth and the level of homecare the owner and the pet is able and willing to perform are another important factor in deciding if the tooth stays or goes. If there are no teeth in the opposing jaw quadrant, or only a small number of teeth remain, treatment favours extraction. The decision to extract also rests heavily on the homecare compliance of the owner and the pet. When homecare cannot be performed because the owner is unwilling or when the pet is unco-operative and thus homecare is unable to be performed, the treatment option for a particular tooth leans heavily in favour of extraction.

Persistent deciduous teeth

The normal pattern of eruption ensures that as the crown of the permanent tooth develops, the pressure promotes resorption of the root of the deciduous tooth, so that once the permanent tooth erupts through the gingival, the deciduous tooth is exfoliated. Therefore, the deciduous and permanent tooth should not occupy the same alveolar socket concurrently. In many of the toy and terrier breed dogs and Persians breed cats, the deciduous canine tooth does not resorb and the permanent tooth erupts adjacent to it, thus two teeth are in the same socket. Extraction of the persistent deciduous tooth as soon as possible should be performed to prevent malocclusions and periodontal disease. When the maxillary canine deciduous tooth is retained, the permanent maxillary canine tooth erupts cranial (mesial) to its deciduous counterpart. All other permanent teeth erupt either lingual or palatal to their deciduous counterparts.

A persistant maxillary right canine tooth in a cat. Note there are two canines, the deciduous tooth occupying the caudal position and the permanent erupting into a cranial position.

A persistant maxillary right canine tooth in a dog. Note there are two canines, the deciduous tooth occupying the caudal position and the permanent erupting into a cranial position.

Interceptive orthodontics / Malocclusions

Class 2 malocclusions occur in young puppies and kittens where the mandible is shorter than the maxilla. This is a genetic, highly heritable condition in Rottweiler dogs. The mandibular canine teeth are often positioned caudal to the maxillary canine tooth and may result in the mandibular canine tooth penetrating the hard palate. The condition is also termed ‘dental interlock’ and the occlusion of the mandibular canine tooth caught caudal to the maxillary canine prevents further mandibular growth and therefore the mandible from achieving its genetic potential. The term ‘interceptive orthodontics’ is selective extraction of deciduous teeth to relieve a current or potential malocclusion.

A Class 2 malocclusion demonstrated by a short mandible compared to the maxilla and the mandibular canine positioned caudal to the maxillary canine tooth in a 10 week old puppy.

Severe periodontal disease

Periodontitis results in loss of the attachment tissues of the tooth including the periodontal ligament, alveolar bone, gingival and cementum. Extraction is recommended when:

1. Homecare compliance is lacking, the owner is not motivated or the pet is unwilling
2. A palatal pocket exists on the maxillary canine tooth resulting in an oro-nasal fistula, detected by nasal haemorrhage on probing
3. Greater than 75% of the tooth attachment is los on more than 2 sides of the tooth and it has not responded to local delivery system antibiotic management
4. Greater than 50% of the attachment is lost on more than 3 sides of the tooth
5. The tooth is mobile more than 4mm
6. A stage 3 furcation exists and the owner is unable to perform adequate homecare
7. A periodontal fistula or sinus exists

A gutta percha point is placed into a draining fistula overlying the buccal aspect of the maxillary left canine tooth.

Periodontal pocket of greater than 10mm on the buccal surface of the mandibular left 3^rd incisor tooth as demonstrated by the periodontal probe placed into the pocket.

Severe periodontal disease as demonstrated by significant gingival recession and stage 3 furcation exposure of all left maxillary premolar teeth.

Highly mobile teeth

Teeth may be mobile as a result of loss of supporting tissues (periodontium), resorption of the root, trauma or subluxation, jaw fracture, or oral tumour.

Endodontic disease

Pulp exposure and subsequent infection with or without periapical abscessation and general systemic infection, requires treatment. Deciduous teeth with pulp exposure should extracted to prevent infection and inflammation of the surrounding area. An increase in temperature will result in cessation of enamel formation in the developing permanent tooth crown, as the ameloblasts are sensitive to a rise in temperature. Permanent teeth with pulp exposure are ideally treated by performing complete pulpectomy (root canal therapy) , but if endodontic treatment is not performed, extraction is recommended in order to remove periapical osteomyelitis and abscessation.

A fractured maxillary right deciduous canine tooth with pulp exposure in a 16 week old puppy.

A fractured maxillary left permanent canine tooth with pulp exposure in a 6 month old dog.

Abrasion of the mandibular left third and fourth premolar teeth due to chewing tennis balls. The third premolar tooth has honey coloured tertiary dentine protecting the underlying pulp, whilst the fourth premolar has an exposed pulp canal, which requires either root canal therapy or extraction.

Impacted teeth

Abnormalities in root development, retention due to a dentiguous cyst or entrapment by fibrous gingiva or bone can prevent a tooth from normal growth and eruption

An absent maxillary 3^rd incisor tooth in a young Beagle dog.

Radiograph of the Beagle confirming the 3^rd incisor has abnormal root development.

Jaw fractures

A tooth in the direct line of a fracture, unless it is required to obtain stability should be extracted

Radiograph demonstrating a mandibular fracture extending through the cranial root of the first molar tooth secondary to advanced periodontal disease.

Oral neoplasia

Extraction of teeth are often performed to enable complete removal of an oral neoplasia during maxillectomy, mandibulectomy, or surgery to repair an oro-nasal fistula, as well as to relieve tension on sutures when gingival tissues are opposed.

Malignant melanoma adjacent to the maxillary second molar tooth.

Severe disease or injury to the crown, neck or root of the tooth

If the tooth cannot be restored and be a functional unit, extraction is recommended.

Caries / cavities in the occlusal surface of the mandibular first and second molar teeth in a Rottweiler dog.

Retained roots

Following crown fracture or tooth resorptive lesions (previously termed feline odontoclastic resorptive lesions), roots may be inadvertently retained, resulting in ongoing inflammation and infection.

Tooth resorption and crown loss of the maxillary right canine and fourth premolar teeth in a cat.

Radiograph of the right feline mandible demonstrating multiple retained tooth roots of the premolars and molar teeth.

Tooth resorption (previously termed feline odontoclastic resorptive lesions)

Tooth resorption is a result of a stimulus that initiates odontoclasts to resorb the tooth crown and root, commonly seen in felines. At this stage the only treatment is extraction.

Radiograph of the right mandible demonstrating early tooth resorption of the premolar and complete resorption of the molar tooth.

Supernumerary teeth

Extra teeth often do not cause a problem, but when they result in trauma or the accumulation of plaque and advancement of periodontal disease they should be extracted.

Supernumerary teeth (maxillary right 3^rd incisor – positioned high in bite) and malocclusion / anterior cross bite (right maxillary 1st incisor with bigeminy (left maxillary 1st incisor).

Essentials for good extraction technique

2.Accessibility to the site

• Proper positioning of the animal

As your dentistry increases in frequency, the ergonomics of the procedure becomes very important. A bad habit performed once may cause a short-term problem, but when repeated all day, every day, it may result in a repetitive strain injury (RSI), permanent tendon, muscle or tissue damage. I place the patient in lateral recumbency. Good lighting and a comfortable chair are important, so that you can do the procedure with a straight back and extended arms.

The following are important factors you should consider when setting up your dental suite. You should be comfortable, have good visibility, improve magnification with loupes, use a chair and table which will provide the needed arm, hand and instrument rests and support and make sure you have a proper fulcrum for hand and instrument support when required.

A wet table and general anaesthetic set-up with a cat attached to the machine.

• Appropriate mouth gag or prop

In order to perform successful dentistry without complications, you must be able to visualise what you are doing. A mouth gag, whether it be a European type that has a wire sprung bar placed caudal to the maxillary and mandibular teeth, or a spring loaded U shaped gag that contacts the tip of the canine teeth on opposite side of the jaw both will allow the caudal oral cavity to be visualized for dogs. If these are not available, a 3cc syringe can be cut off and engaged over the maxillary and mandibular canine teeth, being careful not to over-extend the TMJ.

Cats pose a completely different scenario, with respect to gags. I do not recommend any type of gag or artificial mouth opening device, as there are reports and a published paper on blindness in cats post dental surgery. This is thought to have been caused by pressure on the maxillary artery resulting to lack or cessation of blood to the brain and ultimate blindness. You be better to use your fingers and hand to keep the mouth open.

 

Gags to provide access into the oral cavity.

2.Good visibility

• Proper and precise lighting source

A general light or specific light source can be used. General light is achieved from an overhead light source. It must be moved manually and lights up the general area. Specific light is achieved from either a head mounted light, with or without loupes, or attached to the handpieces on your dental machine. A pair of optical loupes allows the veterinarian to magnify the area they are working on and therefore perform more precise and accurate treatment. A fibre optic light source is available on most high speed

and ultrasonic scalers. It directs light to the area being worked on.

• Loupes

Magnification is paramount for dental procedures. Generally x2.5 – x3.5 is recommended. It is possible to obtain loupes that have a fixed focal distance so the ergomonical seating position is maintained and your back is protected. Loupes will make visualizing the work area better and your work will improve many times fold.

• Cheek and tongue retractors

Plastic cheek retractors are ideal for holding the lips and cheek out of the way. A tongue retractor, such as a Minnesota retractor, can be used to hold the tongue out of the operating field. This is especially important when a high-speed bur or scalpel blades are used.

A Minnesota retractor.

3.Knowledge of tooth root attachment and the anatomy of crown and root

In order to perform a successful extraction knowledge of tooth anatomy and dental tissues are important; as well as, the types and thickness of bone associated with each tooth (important when performing osteoplasty); associated arteries, nerves and veins (important to avoid complications and to promote healing); relevant nerve canals and foramina (especially important for local analgesic nerve blocks); gingiva and sulcus (important for initiating the extraction); shape and number of tooth roots of each tooth (makes the extraction easier and avoids complications when sectioning multi-rooted teeth); shape of the tooth crown; and the periodontal ligament.

Each tooth root is housed within the tooth socket. The processes consist of the alveolar bone (or cribriform plate), compact bone and cancellous trabeculae bone. The alveolar bone lines the tooth sockets, radiographically appearing as a thin white, radio-opaque line, termed the lamina dura. In health, the lamina dura parallels the periodontal ligament. The compact bone covers the outer surface of the processes. The trabecular bone lies between the processes. When performing trans-alveolar extraction, osteoplasty to remove the lateral bone plate will result in removal of both the compact bone and the alveolar bone.

Radiograph of the mandibular 1^st molar tooth showing normal anatomy.

A healthy tooth is composed of two major parts: the supra-gingival portion that extends above the gingiva and is grossly visible, termed the crown, and the sub-gingival portion that extends beneath the gingiva, termed the root. The bulk of the root is composed of dentine. The root has an outer covering of cementum.

The periodontal ligament is a connective tissue that supports and holds the tooth in the alveolus. It also supports and cushions the tooth from external forces. The ligament is composed of collagen and elastic fibres arranged in bundles or groups, with one end attaching to the cementum on the tooth root and the other end attaching to the maxillary / mandibular alveolar bone (cribriform plate). The periodontal ligament contains blood vessels, lymphatics and nerves.

The gingiva is the part of the oral mucosa that covers the alveolar processes and surrounds the teeth. In the majority of animals, after the tooth has erupted to full crown height=”auto”ingiva attaches permanently to the tooth at the cemento-enamel junction. This attachment is via a junctional epithelium and is termed the epithelial attachment. The space created between the free gingiva and the tooth surface is termed the gingival sulcus.

Diagram of a tooth.

4.Radiology

Radiology is a vital tool in veterinary dentistry that can be used to assist in the diagnosis, treatment planning and monitoring of oral disease. It can be utilized to confirm missing teeth; diagnose diseases, such as periodontal and endodontic conditions; and confirm treatment procedures, such as complete tooth extraction.

An ACTEON XMIND wall mounted xray generator.

The ACTEON Sopix2 xray sensor

5.Knowledge of dental formula, tooth types and number, and number of tooth roots

The dental formula for the permanent dentition of the dog is: I³₃ C¹₁ P⁴₄ M²₃

	Dog – number of tooth roots
Tooth	Maxilla	Mandible
Incisors	1	1
Canine	1	1
Premolar 1	1 (occas. 2)	1 (occas. 2)
Premolar 2	2	2
Premolar 3	2	2
Premolar 4	3	2
Molar 1	3	2
Molar 2	3	2
Molar 3	Tooth absent	2

 

Canine Maxilla

Canine Mandible

The number of roots of each tooth in the permanent dentition of the dog.

The dental formula for the permanent dentition of the Cat is: I³₃ C¹₁ P³₂ M¹₁

	Cat-number of tooth roots
Tooth	Maxilla	Mandible
Incisors	1	1
Canine	1	1
Premolar 1	Tooth absent	Tooth absent
Premolar 2	1	Tooth absent
Premolar 3	2 (occas. 3)	2
Premolar 4	3	2
Molar 1	1	2
Molar 2	Tooth absent	Tooth absent
Molar 3	Tooth absent	Tooth absent

 

Feline Maxilla

Feline Mandible

The number of roots of each tooth in the permanent dentition of the cat.

6.Local analgesia injection (pre-emptive analgesia) by regional nerve block

Used in combination with general anaesthesia should be performed to decrease peri-operative pain, as well as, increase post-operative comfort and healing. Purchase of local anaesthetic, syringe and needles.

Aspirating syringe, anaesthetic carpules and dental needles.

7. Synergy osteoconductive synthetic bone material

Synergy is an osteoconductive synthetic material, which can be used in periodontal pockets to promote new alveolar bone production and encourage re-attachment of the gingival tissues and periodontal ligament or into post-extraction sites to maintain bone density.

Synergy crystals are a mixture of tricalcium phosphate and hydroxyapatite.

8. Extraction equipment

The types of instruments that I find useful and necessary for a successful extraction include:

1. Scalpel blade – #11 or #15
2. Periosteal elevator
3. High speed handpiece
4. Round bur – #2 and #4
5. Tapered fissure bur – #699 and #701L
6. Dental instruments – elevators: straight /winged / curved deciduous / root tip pick
7. Forceps
8. Suturing instruments and suture (Safil Quick 3/0 and 4/0)
9. Synthetic bone maerial (Synergy)

High Speed handpiece

Elevators

1.Straight

The traditional elevator is termed ‘straight’. It consists of a handle, shaft and working end. The working end consists of a blade with parallel sides, a concave and opposing convex surface with a rounded tip. The tip may be sharp or blunt.

A straight elevator.

2.Winged #1 – #8

Winged elevators are a variation of the straight elevator. The working end has a concave surface and opposing convex surface, flared sides, with an appearance of a wing, and a rounded tip, which is sharp. The winged elevators were designed by Dr Bob Wiggs, of Dallas Dental Clinic for Animals, Dallas, Texas and are available from a number of companies. The working tip is available in a variety of sizes from 1mm to 8mm, and they are designated #1, #2, etc to #8.

A winged elevator.

3. Feline specific elevators

The EX-5XS perfect for feline teeth.

The 1.3S-XS super slim elevator designed for feline tooth roots.

4. Root tip pick

The root tip pick has a sharp pointed tip that is used to loosen the apical tip of a root if the root inadvertently fractures during elevation.

A root tip pick.

5.Curved deciduous elevator

The curved deciduous elevator consists of a handle with two working ends at opposite ends of the handle. The first end is angled to have a concave surface and is used against the convex tooth root surface, whilst the other end has a convex surface to be used against the concave tooth root surface. It is used on the cranial and caudal surface of a curved deciduous tooth root.

A curved deciduous elevator.

Extraction forceps

Extraction forceps have two handles and two beaks, which are opposed when the handles are squeezed together. The beaks are used to grasp the tooth crown in order to extract it from the alveolus.

A pair of extraction forceps.

Complications of tooth extraction

A complication is any adverse, unplanned event that tends to increase morbidity above what would be expected from a particular operative procedure under normal circumstances.

Complications can be allocated to one of three groups:

Patient factors

Bleeding disorders, tooth deformities, delayed healing, medically compromised patients. The majority of the patient complications can be ruled out following a normal work-up prior to general anaesthesia and clinical examination of the patient.

Surgeon factors

Skill level, experience, poor technique. Not too much to say here! Encourage the Universities to increase the dental education to undergraduates so they graduate with adequate dental knowledge and skills, continue your own dental education by attending CVE courses, webinars or our practical courses.

Procedural factors

Inappropriate tools, complexity of procedure, surgical access, proximity of important anatomical structures. If the surgeon uses the appropriate instrument and follows a standard protocol, the majority of procedural complications are avoided. The most common complication is anatomical variation ie the feline maxillary 3^rd premolar tooth in 11% of patients has three roots rather than the usual two, which would be found on radiographs prior to extraction.

Some of the complications that may be encountered include:

1. Fractured roots
2. Soft tissue trauma
3. Haemorrhage
4. Jaw fracture
5. Oronasal fistula
6. Infection
7. Nerve damage
8. Root(s) lost into soft tissues / cavities
9. Protrusion of tongue post extraction
10. Damage to surrounding teeth

Proper grip of the Instrument

Dental elevators and luxators should be held properly for the best leverage and control. Your hand should wrap around the instrument so the handle rests in your palm, your thumb placed in the thumb clutch groove, which is the indentation at the point the handle meets the shaft. Your middle, ring and little finger should grip the handle of the instrument lightly and the forefinger held tight against the working tip for control. There should be approximately 5mm of the instrument tip extending past the end of your forefinger. Thus if the instrument slips during extraction, it does not penetrate very far into the patient’s soft tissues or your own hand that is being used for support of the head and jaws.

The correct technique of holding a dental elevator.

Extraction technique

A systematic approach to extraction is necessary to achieve success, reduce the chances of complications and ensure reliable results. The following list is the basis of what I use for a dependable extraction plan.

It goes without saying, that all extractions will be performed in a pet under gaseous general anaesthesia with an endo-tracheal in place. I also pack the oro-pharynx with gauze swabs attached to a yellow piece of string so I remember to remove it at extubation. Observe the general cleanliness of the oral cavity and perform a pre-extraction scaling to decrease calculus and debris entering the oro-pharynx or being forced into the extraction site and surrounding tissues during the extraction.

Examine the tooth you are going to extract for physical for signs of disease or injury. The tooth may be suffering from any of the following:

1. Periodontal Disease
2. Fractures
3. Exposure Of The Pulp Chamber
4. Resorptive Lesions
5. Cavities
6. Tooth Mobility
7. Proximity To Major Structures
8. Condition Of The Alveolar Bone
9. Oronasal Fistulas
10. Oroantral Fistulas
11. Tooth Discolouration.

Pre-extraction radiographs are not practical in all extraction cases, but I recommend they should be taken if any of the following are present:

1. A history of difficult extractions in the pet
2. You have particular difficulties with the type of tooth in this species or breed
3. If sectioning the tooth is indicated
4. Any tooth with a close relationship to a major anatomical structure
5. Heavily restored or pulpless teeth
6. Any tooth with periodontal disease accompanied by sclerotic bone
7. Any tooth with tooth resorption
8. Any tooth which has a history of fracture
9. An isolated tooth without an opposing unit
10. Partially erupted teeth, retained roots or deciduous teeth
11. Any tooth with an abnormal crown anatomy
12. Feline maxillary third premolars (they often have either two or three roots)
13. Any animal with generalised disease such as renal complications, hypothyroidism.

Evaluate each tooth and the radiographic findings. Some teeth will be found to be so mobile that they can be easily removed at this point with intra-alveolar elevation and forceps extraction.

Pre-extraction local analgesia injection (pre-emptive analgesia) by regional nerve block in combination with general anaesthesia should be performed to decrease peri-operative pain, as well as, increase post-operative comfort and healing.

Extraction of deciduous teeth

Deciduous teeth that are present when the permanent tooth is erupting, should be extracted immediately. Exodontia is the only treatment choice in cases of persistent deciduous teeth. By the time the pet is 4 months of age, some of the permanent teeth should be erupting. The rule is that if the permanent tooth crown is visible above the gum line, the deciduous tooth should be exfoliated. If the deciduous tooth is present, it should be removed as soon as possible. Leaving it in place until 6 months to be performed at speying or castration is inappropriate because it forces the permanent tooth to erupt into an abnormal location.

If the permanent counterpart has not erupted, the mouth should be radiographed, and if the permanent tooth bud is absent, the deciduous tooth may be left. Exfoliation can be influenced by many factors, such as nutrition, inflammation, trauma, endocrine disorders such as hypothyroidism and ankylosis of the tooth to alveolar bone. Once the adult tooth starts eruption, unless its way is unimpeded, it will be deflected away from its normal position, lingually for most teeth, except for the maxillary canine, which are displaced rostrally. This may result in the mandibular canine tooth being displaced laterally. While the deciduous crown may be ready to exfoliate in some cases, if any root structure remains, it should be completely remove. Persistent deciduous teeth may commonly cause malocclusion such as base narrow canines, where the mandibular canine teeth erupt lingually to the deciduous teeth, or anterior cross bite, where one or more of the maxillary incisors lean lingually to the mandibular incisors (linguoversion). While specific dental malocclusions caused by persisitent deciduous teeth have not been proven to be genetic, as are jaw length discrepancies, any orthodontic adjustment should be thoroughly discussed, including breeding counselling.

The deciduous tooth is extracted by initially severing the epithelial attachment. A #11 or #15 scalpel blade is used to sever the epithelial attachment by running the blade around the circumference of the tooth root after placing it into the gingival sulcus to the level of the alveolar bone. The tooth is then elevated by using a combination of the curved deciduous tooth root elevator, which is a curved instrument with a concave blade on one end and a convex blade on the opposite end. The blade is inserted into the periodontal space occupied by the periodontal ligament so it hugs the curve of the tooth. A small winged elevator or luxator can then be placed into the lateral or palatal/lingual periodontal space and with gentle motion, either rotational (elevator) or flexion (luxator) the periodontal ligament is severed and loosened. It is usual to severe at least 80% of the root length in order to prevent root fracture. Once the root is mobile it can be gently grasped with extraction forceps and rotated and removed. If you find the root fractures regularly then I would recommend using needle drivers/holders to replace forceps so the force is less. Once extracted, check for complete removal and leave the socket open.

Intra-alveolar extraction

For single rooted teeth the following protocol can be used. A #11 or #15 scalpel blade is used to sever the epithelial attachment by running the blade around the circumference of the tooth root after placing it into the gingival sulcus to the level of the alveolar bone.

Diagrammatic sketch showing the positioning of the scalpel blade to commence severing of the epithelial attachment.

The position of the scalpel blade placed subgingivally to commence severing of the epithelial attachment.

An appropriate sized elevator or luxator is chosen. If the elevator is chosen, the concave surface of the instrument contacts the root circumference without any space between them. The handle of the elevator is grasped and the working end placed into the gingival sulcus and against the long axis of the tooth root. The elevator is then forced into the periodontal space on the lateral surface of the tooth. Initially this expands the bony socket by forcing the lateral bone wall outwards, as well as severing the coronal periodontal ligament fibres. It is then rotated along its long axis clockwise and as the blade is wider then the periodontal space it will force the tooth palatally or lingually to the opposite side of the socket, stretching and tearing the periodontal ligament fibres and producing haemorrhage. The haemorrhage will additionally force the tooth root out of the socket. The instrument is held in this position of five seconds and then the tension released. The elevator can then be rotated in the counter-clockwise direction, repeating the steps just mentioned. The elevator can then be removed from the periodontal space and forced into the palatal or lingual surface and the steps repeated as before. As the tooth loosens from the bony socket, changing to larger sized elevators will increase the effectiveness. This action is repeated around the circumference of the tooth until it loosens and can then be grasped by forceps.

If a luxator is chosen, the blade is forced into periodontal space and small back and forth movements are made while applying apical pressure, until the luxator takes a grip and shows resistance. A luxator should not be twisted as this will damage the blade and bend the instrument. The luxator is moved back and forth until the blade moves further into the space, it can then be removed and forced into another position around the tooth. This is repeated until the tooth loosens.

Once the tooth is loose, it may be grasped in the beaks of the forceps. The tooth should be grasped as apically as possible. The tooth can then be forcibly pushed into the socket and rotated clockwise until resistance is felt. It is then held for five seconds, the tension released and the tooth rotated counter-clockwise and held for five seconds. This back and forth motion with continued holding is repeated until the tooth root is loose enough to pull from the socket.

Curved roots are not as amenable to this technique and multi-rooted teeth should be sectioned into individual root sections. Sectioning creates a ‘kerf’ – the space created by the sectioning cut – prior to extraction using intra-alveolar method. Once multi-rooted teeth are sectioned, the same intra-alveolar technique can be used on each individual root segment. All multi-rooted teeth are more easily removed by sectioning into individual segments. Elevators may be used in the ‘kerf’ to lever one root segment against the other, by placing the working tip into the ‘kerf’ between the segments at a perpendicular angle to the long axis of the tooth root. The elevator is then rotated clockwise (or counter-clockwise) with the concave edge of the instrument contacting and elevating the root while the convex surface rests against the other segment. The tension is held for five seconds and then released. The instrument is then reversed and the opposite segment is elevated. This is repeated until both segments are loose, at which point, they can be grasped with forceps and ‘pushed’ and rotated out of the socket as previously described.

Trans-alveolar extraction method

Trans-alveolar extraction method should be performed when:

1. The tooth you plan to extract shows any signs of pathology on radiograph
2. You have been elevating using the intra-alveolar method for longer than 5 minutes and the tooth still is rock solid
3. Retained roots which cannot be grasped with forceps
4. Root tips that are close to the nasal cavity, mandibular canal or maxillary antrum
5. A history of difficult extractions
6. Hypercementosed and ankylosed teeth
7. Teeth with resorption
8. Germinated and dilacerated teeth
9. Teeth on radiograph with complicated root patterns.

The trans-alveolar method is the preferred technique for canine and carnassial teeth extraction. The technique is the same for single and multi-rooted teeth, except that multi-rooted teeth will be sectioned into individual root segments. The technique involves raising a muco-periosteal gingival flap and removal of the alveolar bone overlying the lateral tooth root.

When performed correctly, the trans-alveolar technique is quicker and less traumatic than a prolonged intra-alveolar technique. Trans-alveolar extraction requires the formation of a muco-periosteal gingival flap, utilising a single or double vertical oblique releasing incision/s. The position of the releasing incisions is critical to the success of the extraction. The base of the flap at t he point where it is still attached and hinges should be wider than the free edge which is often the gingival margin> The flap is raised to incorporate the periosteum in order to maintain a good blood supply and give the flap adequate strength and resistance to tearing. The flap should be made to avoid subsequent suturing over the void created by osteoplasy. The flap should be large enough to cover any exposed bone and to prevent tension on the suture line. Specific anatomy (i.e. mandibular frenulum), blood vessels (i.e. infra-orbital vessels) and neurological structures (i.e. mental nerves) should be avoided.

Severing the epithelial attachment

The first step is to sever the gingival epithelial attachment with a #11 or #15 scalpel blade. The tip of the scalpel blade is placed into the gingival sulcus and through the epithelial attachment to the level of the alveolar bone. The blade should be moved around the circumference of the tooth until the entire epithelial attachment is severed. Whilst the scalpel blade is ideal, severing of the attachment can be performed with many instruments, including:

1. A periosteal elevator
2. The sharp tip of a root tip pick
3. Blade of a winged elevator

Making incisions for the muco-periosteal flap

The incisions of the muco-periosoteal flap should be made with a sharp scalpel blade with firm pressure through the mucosa and periosteal layers of the gingiva down to the bone. The maxillary and mandibular canine teeth generally require a single vertical incision with a flap that hinges along a triangular base, whereas most other teeth will require two vertical incisions, one at cranial edge and the other at the caudal edge of the tooth to be extracted.

Position of releasing incisions (dashed lines) of gingival flap for extraction of the maxillary 4^th pre-molar tooth.

Position of releasing incisions (dashed lines) of gingival flap for extraction of the maxillary canine tooth.

Raising the muco-periosteal flap.

The muco-periosteal flap is then raised off the underlying bone and reflected using the sharp edge of a periosteal elevator. The periosteal elevator is inserted into the gingival sulcus and pressed against the bone. The sharp edge of the elevator is pushed between the bone and the periosteum, so that the periosteum is removed from the bone and remains attached to the muco-periosteal gingival flap. This gives the flap strength and a better blood supply, which in turn reduces tearing of the flap, and encourages faster healing post-extraction. The surface of the lateral / buccal bone overlying the tooth root is exposed once the muco-periosteal flap is raised.

A raised muco-peristeal flap overlying the maxillary right fourth pre-molar tooth in a dog, exposing the underlying buccal alveolar bone. Note the vertical incisions are not immediately between the teeth, but slightly into the adjacent tooth, which is ideal for healing.

A raised muco-peristeal flap overlying the maxillary right canine tooth in a dog, exposing the underlying buccal alveolar bone. Note the single vertical incision is caudal to the tooth and the flap is hinged / reflected at a 45 degree angle.

Removal of the buccal alveolar bone plate.

The overlying buccal bone should not be removed unnecessarily. The bone overlying the maxillary teeth is relatively thin, a couple of millimetres, compared to the mandibular bone, which is very thick, often 6mm on the buccal surface of the first molar tooth in a large breed dog. The mandibular bone gets thicker as you move apically and caudally, so that at the alveolar margin the bone is 1mm thick, whereas overlying the lateral mandibular first molar roots, it can be up to 6mm thick. It is important to only remove bone from either the lateral or the medial side of the tooth root. Do not remove bone from both the lingual and buccal or palatal and buccal surfaces of the tooth root as it significantly weakens the mandible or maxilla.

A # 2 or #4 round shaped bur on a high-speed handpiece with water-cooling can make fast work of removing the bone plate. Initially the entire buccal bone plate overlying the tooth root can be removed. Once you have performed the procedure a number of times and are confident with the anatomy of the tooth root, a U shaped incision can be made with the bur that separates the bone attachment to the tooth root.

Once the buccal bone plate has been removed, the bur can be used to make a small groove along the cranial and caudal surfaces of the tooth root. The groove at the cranial and caudal aspects of the tooth root creates a space for elevator placement.

Following osteoplasty, the bone overlying the maxillary right canine tooth in a dog has been removed and grooves have been created on the cranial and caudal aspect of the tooth root. With the bone removed, the root cementum and dentine is now visible.

Following osteoplasty, the bone overlying the maxillary right fourth pre-molar tooth in a dog has been removed, the furcation is visible and the two buccal roots can clearly be seen. With the bone removed, the root cementum and dentine is now visible.

Placement of a winged elevator into the cranial groove adjacent to the maxillary right canine tooth in a dog.

Sectioning multi-rooted teeth into their individual root segments will make extractions much easier. Sectioning can be performed using the same round bur or a #699-701 crosscut fissure bur with a water-cooled high-speed handpiece. It is best to visualise the furcation and section the tooth starting at the furcation and cut towards the crown. Once the furcation is visualised, place the bur through the furcation and out the other side. The cut is then made from the furcation through the middle of the crown. The roots of most teeth are a mirror image with the furcation in the middle, so a central cut is required. The mandibular first molar in the dog and cat have different sized roots, with the cranial root being much larger than the caudal root. The furcation is also slightly caudal from the centre of the tooth, so the sectioning should be made from the furcation into the developmental groove. The maxillary fourth premolar has three uneven sized roots in both the dog and the cat. The distal root is large and wide, the mesio-buccal root is longer and thinner and these are both positioned on the buccal aspect of the jaw. The third root, the palatal root, is thin and angled in a palatal direction. The palatal root is best sectioned by placing the bur between the mesio-buccal root and the palatal root with the tip angled buccally at approximately 30 degrees to the vertical.

Using a high-speed bur in the furcation to section the maxillary 4^th pre-molar tooth into individual distal and mesial roots.

Following sectioning of the maxillary right fourth pre-molar tooth in a dog to divide the mesio-buccal and the distal root segments.

The appearance of the tooth following sectioning of the maxillary right fourth pre-molar tooth in a dog to divide the mesio-buccal, the distal root and the palatal root segments.

The appearance of the tooth following sectioning of the mandibular right fourth pre-molar and first molar teeth in a cat to divide the mesial and distal root segments.

The appearance of the teeth following sectioning of the maxillary right fourth pre-molar tooth in a cat to divide the mesio-buccal, the distal root and the palatal root segments and the third premolar to divide the mesial and distal root segments.

Once the teeth have been sectioned into individual root segments, the next step is to sever and fatigue the periodontal ligament. This is done by placing the elevator into the periodontal space between the tooth root and the alveolar bone. Force the elevator along the tooth root in an apical direction, using a back and forth light twisting motion as you press down into the ligament space, until you gain a short 1-2 mm depth. Once there is some resistance to the clockwise twist, hold the tension on the instrument for five seconds, which stretches and fatigues the periodontal ligament. Continue to work circumferentially around the tooth, repeating the above action. Eventually the tooth will loosen and the periodontal ligament will fatigue until it begins to elevate out of the socket, and can be easily removed with a pair of extraction forceps as previously described.

Placing the elevator parallel to the tooth root into the ‘kerf’.

Stressing the periodontal ligament by placement and gentle rotation of the elevator in the ‘kerf’ between the two crown segments.

A pair of extraction forceps are used to grasp the tooth root. A gentle rotation while pushing into the socket will aid in extraction.

Care should be taken with extraction of the maxillary canine teeth. The canine tooth root curves caudally and is bound on the buccal side by the thick alveolar bone but a thin plate of bone on the palatal side which is easily damaged by both osteomyelitis and trauma by extraction. If excessive force is placed on the palatal side of the tooth by the elevator or luxator, they may perforate the alveolar bone and enter the nasal passage and contribute to formation of an oronasal fistula. When periodontal disease thins the bone on the palatal side of the tooth, an oro-nasal fistula may already exist and no amount of care will prevent penetration of the elevator into the nasal cavity. Therefore, always use a periodontal probe on the maxillary canine teeth to check for deep palatal pockets before initiating the extraction. This will reduce the chances of creating an iatrogenic oro-nasal fistula on the palatal side. Additionally, always rotate the crown tip laterally rather than palatally during extraction to reduce the chance of the root apex being forced into the nasal passage.

Using dental forceps to extract the maxillary right canine tooth in a dog.

Following extraction the apical end of each tooth should be checked by running your finger over the tip, to ensure that the entire root has been extracted. If the tip is rough and sharp, it is highly likely that the root has fractured. If the tip is smooth then the root has been completely removed.

If granulation tissue or debris is present in the tooth socket, curettage and debridement of the sulcus after extraction with a bone or periodontal curette, or surgical or periosteal elevator is indicated as well as flushing with 0.12% chlorhexidine solution.

If bony spicules or irregular alveolar bone is present along the edge of the bony socket, which can be palpated with the tip of your finger as it catches on your glove, osteoplasty using a small round bur should be performed until a smooth edge is palpated. Leaving rough edges delays healing and irritates the pet, often seen as pawing at the mouth or chewing on the opposite side of the mouth.

Using a high speed bur to smooth any rough edges post-extraction.

Post extraction radiology is indicated in all complicated extractions to assure removal of all root fragments, as well as to assess the condition of the adjacent teeth and bone for fractures and to provide proof of complete extraction.

Placement of osseous inductive products (Synergy, Calcium Phosphate and Hydroxyapatite preparations with or without added doxycycline) that enhance bone growth into the empty socket should be placed following extraction. Following extraction, resorption of the alveolar ridge and ventral mandible border occurs. This is most prevalent in the rostral area of the mandible. It is most commonly observed in conjunction with periodontal disease. This may result in a pathological fracture in the future in an older animal.

After the extraction is complete, the muco-periosteal flap should be replaced and sutured. The intact free edges of the flap should be debrided so that free epithelial edges oppose each other. If you are having difficulties in opposing the edges, a scalpel blade can be used on the internal surface of the flap to sever the periosteum, which will allow the flap to be stretched. The flap must be opposed under no tension using absorbable 3-0 or 4-0 suture material in a simple interrupted or vertical mattress pattern. I use Safil Quick on a swaged needle PS-2. Haemorrhage in the short term can be controlled with pressure on a swab for five minutes and in the long term is better controlled when the flap is opposed and the blood clot stays in the socket better. Gingival tissue granulates over a clot faster than exposed bone. The pet heals faster and with less pain, eats better and requires lower analgesic dosage at home.

After extraction and packing, the gingiva is sutured with 4/0 absorbable vertical mattress sutures.

I would encourage you to use the trans-alveolar method for difficult to extract teeth. Although a tooth that is ankylosed to the surrounding bone can be removed by atomise / pulverise the root segment using the high-speed handpiece with a round or pear bur, I personally do not use or advocate pulverisation as a treatment for extraction, as complications are high. It has been suggested as a treatment for feline teeth with odontoclastic resorptive lesions though. If you wish to use pulverisation, it should only be done with excellent visualisation and when radiographic support is available. Adequate water irrigation during this process is necessary to prevent bone necrosis from excessive generation of heat.

Prior to atomisation, a radiograph should be taken to ascertain the length of the tooth root and the proximity of any adjacent anatomical structures. The bur would then be used to pulverise the root and a radiograph taken to confirm the root has been removed in its entirety. A trans-alveolar approach is recommended. Otherwise, crown amputation and suturing the gingiva over the resorbing root and radiographic monitoring is preferred. It has been reported that feline tooth resorption can be treated with crown amputation and gingiva coverage. Following radiographs to confirm there is no periapical pathology, the crown is amputated and the gingiva sutured over the roots. Radiographs are taken three months post-operatively to ensure healing. If there is any pathology then the tooth root should be extracted in its entirety.

Home care medications and instructions

1. Soft food including 1cm chunks of chicken or beef, minced meat, lightly steamed vegetables, pasta for 4 – 7 days
2. Call the clinic if excessive bleeding or pain is noticed
3. Gentle flushing using Maxiguard or OraZn twice daily
4. Dispensing of antibiotics (clindamycin 11 mg/kg bid 5 days) as required.
5. Dispensing of pain relief medications (NSAID 5 days).
6. Recheck animal in 10-14 days.