6: Removal of teeth and surgical implantology

Removal of teeth and surgical implantology

6.1 Dental extractions

Assessment for extraction

History and clinical examination

The assessment of the patient has already been described in Chapter 2. A thorough medical history prior to any surgical procedure is obviously essential. This will identify patients who may require special preparation prior to even the simplest dental extraction. Such patients may include those taking anticoagulant medication or those that have undergone irradiation, among many others (Chapter 3). The information obtained will also determine whether surgery should be undertaken by the general dentist or specialist and also the choice of setting. The home circumstances and availability of an escort may also be important if considering conscious sedation or general anaesthesia.

The history also includes questions about previous dental and surgical experience and assessment of patient anxiety (Chapter 4). The sex, general build of the patient or other factors may give an indication as to the expected ease or difficulty of the extraction. For example, an extraction is likely to be more difficult in heavily built men, elderly patients may have more brittle teeth and Afro-Caribbeans more dense alveolar bone, while child patients may have reduced access and less cooperation.

The intraoral examination should include a note of the access to and position of the tooth. The crown of a heavily restored tooth is more likely to fracture during extraction, while endodontically treated teeth may be more brittle.

Radiological examination

Preoperative radiographs need not be taken prior to all extractions, but there are situations when radiographic assessment is essential to demonstrate root morphology, anatomical relationships or associated pathology (Box 6.1). Mandibular and maxillary third molar teeth are known to show a wide variability in root morphology, and so pre-extraction radiographs should always be taken. It is also essential to know the relationship of the inferior alveolar canal in the case of the lower third molar. Cone beam computed tomography (CBCT) is indicated when an intimate relationship of the third molar and the inferior alveolar nerve canal is observed on plain film. In general, where any difficulty is anticipated, it would be wise to take a radiograph before rather than during the extraction, so that the procedure may be planned appropriately. Where a radiograph is judged to be necessary, a periapical view should be the first choice, although other films may be substituted or used in addition when indicated (e.g. panoramic or lateral oblique for lower third molar).

Surgical techniques

Instrumental extraction

To extract a tooth from the alveolus, the periodontal attachment must be disrupted and the bony dental socket enlarged to allow withdrawal of the tooth. To achieve this, various instruments have been developed:

There are several different forceps extraction techniques described and some basic principles and guidance are required when learning. Forceps are used to disrupt the periodontal attachment and dilate the bony socket either directly, by forcing the blades between tooth and bone, or by moving the tooth root within the socket, or both. Once this has been done, the tooth may be lifted from its socket. The movements that are required to complete the extraction may be described as a preliminary movement to sever the periodontal membrane and generally dilate the socket, followed by a second movement to complete the dilation and withdraw the tooth. The first movement requires that force is directed along the long axis of the tooth, pushing the blades of the forceps towards the root apex. This force is then maintained during the second movement, which is dependent on the tooth root and bone morphology. If a tooth has a single round root, then it may be rotated. Where the buccal bone plate is relatively thin, it may be possible to distort it significantly by moving the forceps applied to the tooth root in a buccal direction. The second movement depends on the tooth and may be described as:

Alternative techniques for forceps movement are advocated by some, including a ‘figure of eight’ movement to expand the socket for molar teeth. Elevators may be used to carry out the first movement prior to completion of the extraction with forceps. Sometimes teeth and roots may be removed with elevators alone. There are many different designs of elevator (Fig. 6.1). The most commonly used are:

It is important that elevators are used appropriately, with their blades between root and bone rather than between adjacent teeth, or else both teeth will be loosened.

There are many designs of forceps. The blades vary in size and shape according to the root morphology of the tooth/teeth for which they are designed. For example, lower molar forceps incorporate a right angle between blades and handles, while the blades each have a central projection to accommodate the bifurcation. Upper ‘root’ forceps have narrower blades than the equivalent upper premolar forceps.

It may be difficult to apply forceps to teeth that are outside of a crowded dental arch and elevators may be more appropriate for initiating the extraction or for the whole procedure. The applied force should be controlled and limited when using both elevators and forceps so that the soft tissues are not accidentally injured or the jaws fractured. Only with experience is it possible to know that the usual force is not producing the expected result, when further investigation is required with a radiograph (if not already available) or a transalveolar approach required.

The non-dominant hand is used to support the mandible against the force of the first movement when extracting lower teeth. It is also used to retract the intraoral soft tissues and, by supporting the adjacent alveolus, provide feedback of movement as a measure of control.

The patient should have eye protection; if the treatment is carried out under local anaesthesia, then the patient may be placed in a position between sitting up and supine or treated supine. Treatment under conscious sedation or general anaesthesia will dictate the supine position. Lower right quadrant extractions are best performed with the operator standing behind the patient; for all other extractions, the operator should stand in front of the patient.

Surgical removal of teeth

Tooth roots, teeth resistant to forceps extraction and those that fracture during extraction need to be removed surgically. However, it may be acceptable to leave a very small root apex if there is no associated periapical pathology and the anticipated surgical morbidity is significant. The patient must be told if any fragments are to be retained.

Teeth are surgically removed by a transalveolar approach. The procedure is described in Box 6.2.

Surgical flap design

A mucoperiosteal flap is a full-thickness flap including oral mucosa and periosteum and is raised to provide access to the underlying bone. The flap should be large enough to permit visualisation of the underlying tissues and have a broad base to ensure adequate blood supply. The design should ensure that the margins be placed on sound bone on wound closure otherwise there is a risk of wound dehiscence (breakdown) and papillae should not be divided.

There are a number of anatomical structures to consider when designing oral flaps: mental nerve, lingual nerve, greater palatine artery and nerve, and nasopalatine nerve.

The mental nerve emerges from the mental foramen usually between the mandibular premolar tooth root apices. Its position should be confirmed on a preoperative radiograph so relieving incisions can be planned to avoid it. Flaps in this area should be retracted with care to avoid stretch or crush injury to the nerve.

The lingual nerve lies adjacent to the medial surface of the body of the mandible and is high up and superficial in the region of the lower third molar just beneath the mucosa. Surgical incisions are therefore best kept buccal to avoid the nerve.

The greater palatine artery and nerve lie in the palate (see Fig. 6.6 on p. 128) and can be safely retracted within an envelope flap to provide adequate access. The nasopalatine nerve and vessels emerge onto the palate via the incisive fossa in the midline just behind the maxillary central incisor teeth. The neurovascular bundle may have to be cut with a scalpel blade to allow a palatal flap to be raised and it is preferable to do this rather than to tear the bundle. Bleeding can be readily controlled with pressure for a short time and loss of sensation to the anterior palate is usually not of concern to the patient although it should be mentioned in advance of the procedure.

The three most commonly used mucoperiosteal flaps used in oral surgery are the envelope (one-sided), two-sided and three-sided flaps. The envelope flap can be used for removal of superficial retained roots that require little or no bone removal as the access is limited. It can also be used palatally when the access provided is good. The incision in an edentulous patient is made along the crest of the ridge but care must be taken when the mandible is atrophic to avoid the mental nerve which is at risk because of its relative superficial position.

The two-sided flap is used when greater access is required. A relieving incision is usually made from the anterior aspect of the flap to maximise vision. A three-sided flap has anterior and posterior relieving incisions to provide the greatest mobility of the flap and access (see Fig. 5.9 on p. 96).

Postoperative care

Control of postoperative pain is important (Chapter 4). Some clinicians prescribe antibiotics if bone removal is necessary. There is some research evidence to support the use of corticosteroids to reduce postoperative oedema and trismus.

Patients should be given a written set of postoperative instructions (Fig. 6.2) and these should be also given verbally before the patient leaves.

Complications of dental extractions

Excessive bleeding

It may be difficult to gauge the seriousness of the blood loss from the patient’s history, because they are usually anxious. However, it is important to establish whether or not the patient is shocked by measuring the blood pressure and heart rate. This can be done while the patient bites firmly on a gauze swab to encourage haemostasis. Typically, if the systolic pressure is below 100 mmHg and the heart rate in excess of 100/minute, then the patient is shocked and there is an urgent need to replace lost volume. This may be done by infusion of a plasma expander such as Gelofusine or Haemaccel or a crystalloid such as sodium chloride via a large peripheral vein. For this purpose, the patient should be transferred immediately to hospital. More commonly, the patient is not shocked and can be managed in the primary care setting.

The next step in management is to investigate the cause of the haemorrhage by taking a history and carrying out an examination.

Dry socket (alveolar osteitis)

In some cases, a blood clot may inadequately form or be broken down. Predisposing factors of osteitis include smoking, surgical trauma, the vasoconstrictor added to a local anaesthetic solution, oral contraceptives and a history of radiotherapy. The exposed bone is extremely painful and sensitive to touch. Dry socket is managed by:

Osteomyelitis

Osteomyelitis (Chapter 5) is rare but may be identified by radiological evidence of loss of the socket lamina dura and a rarefying osteitis in the surrounding bone, often with scattered radio-opacities representing sequestra (see Figs 5.20 and 5.21 on p. 105 and 106).

6.2 Impacted and ectopic teeth

Assessment

In the context of teeth, the term ectopic is applicable to a tooth that is malpositioned through congenital factors or displaced by the presence of pathology. It includes impacted teeth. Impaction may occur because there is no path of eruption because the tooth develops in an abnormal position or is obstructed by a physical barrier such as another tooth, odontogenic cyst or tumour. Most commonly affected are:

Less commonly affected are:

An impacted tooth may be completely impacted, when entirely covered by soft tissue and partially or completely covered by bone within the bony alveolus, or partially erupted, when it has failed to erupt into a normal functional position. The terms unerupted and partially erupted are commonly used for normally developing as well as impacted teeth. It is important, therefore, to distinguish between impaction and normal development.

Radiological examination

Radiological examination should be based upon clinical history and examination. Routine radiographic examination of unerupted third molars is not recommended. Radiological assessment is essential prior to surgery but does not need to be carried out at the initial examination if infection or some other local problem is present. The views used are:

Radiological assessment of impacted teeth should cover:

Diagnosis

Only gold members can continue reading. Log In or Register to continue

Jan 9, 2015 | Posted by in Oral and Maxillofacial Pathology | Comments Off on 6: Removal of teeth and surgical implantology
Premium Wordpress Themes by UFO Themes