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Extraction – an introductory guide to approach and technique

Alexander J Smithson MRCVS
Veterinary Dental, Oral & Maxillofacial Referrals

Extractions are a common surgical procedure; indeed the ability to perform basic extractions is generally classed as a day one competency. Based on prevalence, approximately 30% of each daily operating list may be anticipated to be dentistry related, with extraction being a frequent necessity or treatment option. Various extraction techniques exist and the operator should be familiar with these, in addition to the indications for extraction, in order to appropriately advise clients and treat patients. It should also be remembered that extractions have the potential to cause a high degree of pain and collateral damage; in humans for example anticipated discomfort from surgical extraction is classified within the bracket of severe pain and amongst the most painful of surgical procedures.

Extraction techniques are broadly divided into:

Closed (‘simple’ / ‘intra-alveolar’) - techniques are used to displace the tooth within the alveolus
Surgical (‘open’ /’trans-alveolar’) - this involves formation of a soft tissue flap to access the underlying alveolar (socket) bone, followed by removal of an amount of alveolar bone in order to better access tooth root and thereby facilitate extraction.

Essential Anatomy

Prior to surgery and during planning revise and identify the salient anatomy. Structures adjacent to teeth such as the nasal cavity, neurovascular bundles and the eye are at risk of serious iatrogenic damage.

figure 1 and 2 - dental anatomy

Indications for Extraction

It is important to be able to fully assess the mouth and make a diagnosis of common cases where extraction may be required. The mouth should be fully charted. A pre-operative, diagnostic radiograph is required to appropriately plan treatment.

Indications for extraction include: 

  • Trauma – fracture, wear
  • Abscess & infection
  • Caries (‘dental decay’)
  • Periodontitis
  • Stomatitis
  • Resorptive lesions

It is also essential to recognise that alternative treatments are available and may be appropriate or preferable. Client, patient and local factors which incorporate clinical, practical and financial considerations influence these options. Education of ones self in order to educate clients and enable them to make an informed decision and consent is critical. Example alternative treatments may include: 

  • Maxillofacial surgery
  • Medical treatment
  • Endodontics e.g. root canal therapy
  • Orthodontics e.g. tooth movement, reshaping teeth
  • Restoration e.g. fillings for caries-affected teeth
  • Periodontal surgery

 **A pre-operative, diagnostic radiograph is required to appropriately plan treatment**

Surgical Preparation

The field for surgery should be made clean, as with surgery elsewhere on the body. Gross build-up is removed using a scaler (also to allow visualisation and examination via probing) and topical antimicrobial chlorhexidine gluconate applied to all soft and hard tissue surfaces. Debris must not be allowed to migrate into surgical sites or into the trachea. Prophy paste, if used to polish teeth, should be rinsed away to prevent it contaminating extraction sites. Some surgeons advocate use of a throat pack (sponge or large swab) to protect the trachea from solids, however this offers very limited protection from fluids and must be tied to the ET tube to ensure it is to not forgotten on extubation. Ensuring a well-fitting ET tube and downward tip of the nose relative to the rest of the body assists protection of the airway from fluids.

While antibiotics are rarely indicated, it is essential to provide adequate analgesia. A multi-modal, pre-emptive approach to pain relief is required. Analgesics are often incorporated into pre-medicant protocols and may include opiates and NSAIDs, local analgesic techniques are used once the patient is anaesthetised and diagnosis obtained.

Surgical Equipment

It is essential that extraction is recognised as a surgical procedure and equipment maintained as such. Equipment should be used only for the specific use for which it was intended. The blades of instruments must be kept sharp – a blunt instrument is dangerous as the operator is tempted to use force, often leading to slippage. Damage to adjacent anatomy such as neurovascular bundles or the retrobulbar space of the eye, is often unknown at the time and hidden by overlying soft tissues. Sharpening performed on a daily basis is rapid and efficient, requiring only a sharpening stone and, with many stones, special sharpening oil. It is important to avoid contamination of the stone – clean and sterilise (autoclave or cold sterilisation) instruments before sharpening, then wipe clean, pack and autoclave afterwards.

Instruments are most easily used when packed as kits, the author preferring a small breed/ feline kit separate to a standard canine kit, thus only the appropriate items are used or contaminated at any one operation. Different coloured instrument trays enable coding and easy identification, in addition to keeping instruments together. These, along with the hand instruments, are cleaned and sterilised in the same manner as any surgical equipment, usually for the appropriate cycle of an autoclave. During the cleaning process all edges and hinges should be checked, with any damaged items removed for repair or replacement.  See Oral assesment & extraction kit guide.

Hand Instruments 

  1. Elevators – e.g. Couplands. Modified bone gouges. Sharp but robust. Wedging or rotation
  2. Luxators – Modified scalpel blades. Sharp and slim. Apical movement into PDL space.
  3. Forceps – ‘paired elevators’. Robust. Used on roots. Expand the alveolus.

 figure 3 - elavators (red) and luxating instruments (blue)These instruments are held in a palm-grip. In the case of elevators and luxating instruments, the fore-finger is placed along the instrument’s shank such that only a short portion of blade tip is visible beyond the finger-tip. The elevator is prevented from slipping far as the forefinger on the elevator acts as a ‘stop’, contacting the finger of the supporting hand – since only a tiny amount of blade protrudes beyond the forefinger tip of the dominant hand, minimal damage to either patient or operator is likely. Select appropriate patterns and sizes by matching the blade of the instrument to the curvature of the root circumference. This may vary with species, breed, tooth type and area of root selected to work on.

The opposite hand supports the area of jaw around the tooth designated for extraction, with the thumb and forefinger ‘pinched’ around the tooth. This counters movement during extraction and prevents unchecked trauma should slippage of the instrument occur.

All movements should be smooth and use controlled force. This gradually shears the periodontal ligament fibres and subtly expands the socket, enabling atraumatic extraction.

Never :
- use instruments like a crowbar
- lever off / use against healthy adjacent teeth
- rush extractions with excess force or rapid movements

1. Luxators/ Luxating elevators... essentially modified scalpels, these sharp and slim instruments have delicate blades. They may be used to initiate extractions but do not use force or rotation.
Insert into periodontal ligament space, advance apically (towards root apex) with a forward and subtle rocking motion to allow the blade to find its path in the PDL space between root and alveolar wall.
Instrument slippage is a major concern; ensure that a palm grip with finger stop is always used.

2. Elevators... sharp but robust, these instruments are essentially a modified bone gouge.
They may be used between root and bone (or between multiple roots provided each is to be extracted), elevating teeth via wedging or rotational forces.
Wedging : apical advancement of the elevator between root and alveolar bone
Rotation: tension is applied to the root indirectly, using a fulcrum. Vertical and lateral rotation may be used.
For each technique patience is required, applying controlled and balanced force for 10-20seconds.

3. Forceps... used only on roots – will fracture or slip off crowns. Drive the blades below the gingival to engage on the roots, ensuring that gingiva is not trapped in the beaks.
Forceps have two blades ‘beaks’; their inner curvature should match the curve of the root’s outer circumference in order to prevent excess force being concentrated at spots on the tooth and leading to fracture or slippage. Few patterns exist for animals thus fit is often poor - do not use ill-fitting forceps.
Firmly grasp the root and, supporting the region of jaw, apply controlled apical force – count 10seconds.
Once a tooth has been loosened within its socket, use smooth, gentle force to further loosen and extract teeth, do not simply pull, rotate or lever the tooth as trauma is likely. Some authorities recommend that forceps are not used at all in animals or are only used as the end stage of extraction, once the tooth is already very loose.

4. Periosteal Elevators... used to lift mucoperiosteal flaps for surgical extraction by advancing between periosteum and bone.
The concave surface faces the bone and convex the figure 4 - periosteal elevatorsperiosteum; the sharp tip is directed downwards on to bone and gently rocked and moved across the bone to undermine the flap.

Held in a palm grip with finger stop. The opposite hand applies light force to tissue above the elevator’s blade, providing a stop and reducing likelihood of upward blade movement and flap perforation.
Useful patterns include: Dogs – Goldman-Fox, Small dogs/cats – 2/4mm or 2/3mm (double ended)

Tooth Cutting

High speed handpieces rotate at 300,000-500,000rpm and are designed to cut tooth. They are very useful for sectioning multi-rooted teeth into individual root portions by cutting from the furcation towards the crown (away from soft tissue).

Hand-pieces should be held using the modified pen grip. This allows a secure grip, stability and support via a finger rest ‘fulcrum’ and fine control of bur direction.

Very light strokes should be used- do not press on the tooth – to prevent the bur jamming and stopping, damaging the hand-piece.

Ensure all hand-pieces are cleaned, oiled and autoclaved between patients.

Bone Cutting

A variety of instruments may be used for bone cutting, contouring and removal. Rongeurs (‘bone nibblers’) are ideal for contouring/ smoothing bone after surgical figure 5 - rongeur 'beaks'extractions. Power equipment provides rapid removal and cutting of bone.

Low speed oral surgery hand-pieces rotate at around 10,000-40,000rpm and are designed to remove bone. They require irrigation via sterile bags of physiological solution e.g. Hartmann’s solution or saline and provide the following benefits: 

  • No air outlet towards tissue: prevents potential for emphysema and air emboli
  • No contaminated water and air to force microbes and debris into tissue
  • Directed cooling irrigant helps prevent thermal bone necrosis
  • Physiological , sterile irrigant used
  • Low-speed provides good tactile sensation feedback to the operator

Burs... useful bur patterns include:

  • High speed – FG TC round size 0.5, 1, 2 (cats) 2 & 6 (dogs) FG= friction grip TC=tungsten carbide
  • 701L (fissure bur – to section teeth. dogs)
  • Low speed – HP TC round size 0.5 – 6 as above

 figure 6 - burs; FG round size 6 (red) and FG fissure bur (blue)

Techniques

Extraction is also referred to as ‘exodontics’ in many (primarily human) texts.

Closed Extraction

Also known as ‘simple’ / ‘intra-alveolar’ technique. No soft tissue flaps or bone removal is involved however multi-rooted teeth normally require division into individual root portions. Luxating instruments and elevators are used to displace the tooth within the alveolus. Forceps may be used on loosened teeth if necessary and if correct technique is used, with close fitting forceps.

Closed extraction technique is most appropriate where it is anticipated that extraction will not pose great difficulty. Criteria for inclusion thus include teeth with small single roots (e.g. incisors), normal root anatomy and mobile multi-rooted teeth. A pre-operative, diagnostic radiograph is thus required to correctly plan surgery.

 

figure 7 - 15 - closed extraction

figure 7 - 15 - closed extraction

Surgical

Surgical (‘open’ /’trans-alveolar’) extraction involves formation of a soft tissue flap to access the underlying alveolar (socket) bone, followed by removal of an amount of alveolar bone in order to better access tooth root and thereby facilitate extraction. Bone removal allows visualisation and removes some tooth support.

 

figure 16 - 22 - surgical extraction

Surgical technique is often employed from the outset of an operation where a tooth is unlikely to be easily extracted via closed technique. Examples are canine teeth, immobile multi-rooted teeth, teeth affected by resorption (e.g. cats) or ankylosis (e.g. stone chewers). Other factors include concurrent disease e.g. periodontitis and bone destruction, and individual facial bone density and shape.

Pre-operative investigation and imaging will guide the operator to the preferred initial approach. Where difficulty is experienced during closed extraction, surgical extraction may be employed. Surgical technique may appear more invasive than closed technique, however, controlled, surgical procedures are far preferable to struggling with theoretically ‘less traumatic technique’ and resulting in tissue damage, healing delay and pain. Analgesia for 2-7days post-operatively should be selected based on the procedure type and quality; greater pain and likelihood of infection is anticipated with increased exposure time and trauma.

Simplified flow diagram for extraction technique selection:Specific teeth and situations require technique variations to best achieve atraumatic extraction. The surgeon must assess the likely approach and complications in advance and be prepared to alter this based on radiographic or other investigations. For example, surgical extraction may prove necessary for a tooth which was originally deemed as suitable for closed extraction, due to ankylosis or root shape. The wise surgeon exercises caution, ensuring adequate time, correct equipment and appropriate training and skill before embarking upon surgery. Where root fracture occurs and concern exists regarding likely trauma in order to obtain the root tip, radiograph the area, irrigate with saline or Hartmann’s solution and surgically close the site, provide analgesia and antibiosis for 3 days, monitor and obtain an expert opinion. If in doubt prior to any procedure, seek advice and endeavour never to start something you cannot adequately finish.

This article article was kindly sponsored by Midmark, manufacturer and supplier of veterinary anaesthesia, dental and monitoring equipment.

Midmark


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