Coronectomy Alternative Wisdom Teeth Extraction Health And Social Care Essay

Clinical Scenario

A female patient aged 23 attends her general dental practitioner with repeated episodes of pain from the back of her lower jaw. Intra oral examination reveals swelling, soreness and erythema overlying the operculum of a partially erupted wisdom tooth, indicating pericoronitis. Radiographic examination reveals an impacted wisdom tooth with narrowing of the root and loss of the inferior alveolar canal lamina dura.

Realising the potential complications, the general dental practitioner refers the patient to the oral and maxillofacial department of the dental hospital where you are working as a Senior House Officer. Upon consultation, the patient reveals that she is worried about the complications associated with the procedure, and whether it will affect her future career as an actress. She informs you that a friend of hers recently underwent wisdom tooth extraction and as a result can no longer feel her lower lip and tongue. She asks you questions such as; what are the chances of this happening to me? how long will it last? and is there are any alternative treatments? Upon reviewing the radiographs, you realise the associated high risk of nerve damage to this patient, and recall that you recently overheard a fellow colleague talking about coronectomy as an alternative to extraction of wisdom teeth. You remember the colleague saying that this technique reduces post operative complications, and wonder if this technique would be a suitable treatment option for this patient. Before informing the patient, you want to know if there is any evidence to support this technique, and its potential harms and benefits.

Introduction

If present, third molar teeth normally erupt between the ages of eighteen and twenty four.3 An evolutionary reduction in jaw size coupled with a less abrasive diet makes the problem of impacted wisdom teeth somewhat inevitable in modern humans.1 Impaction arises when there is prevention of complete tooth eruption due to lack of space, obstruction or development in an abnormal position.3 This may result in the tooth erupting partially or not at all. Pericoronitis can be defined as an infection involving the soft tissues surrounding the crown of a partially erupting tooth, and is the most common reason for wisdom tooth extraction. Its signs and symptoms include facial and intra-oral swelling, soreness, erythema, trismus, raised temperature, lymphadenopathy and general malaise.

Hospital episode statistics for 2009/2010 show almost 12,000 out patient and 65,000 in patient admissions for surgical removal of wisdom teeth, making it the most common oral surgery procedure performed in the UK.

The NICE guidelines for extraction of third molar teeth suggest that their surgical removal should be limited to patients with evidence of pathology.3 Such pathology includes “unrestorable caries, non-treatable pulpal and/or periapical pathology, cellulitis, abscess and osteomyelitis, internal/external resorption of the tooth or adjacent teeth, fracture of tooth, disease of the follicle including cyst/tumour, tooth/teeth impeding jaw surgery, and when a tooth is involved in or within the field of tumour resection.”3 According to the NICE guidelines wisdom tooth extractions cost the NHS in England and Wales up to £12million per year.3 The guidelines published in 2000 dramatically changed the practice of wisdom tooth extraction. The guidelines do not support the prophylactic removal of pathology free impacted third molars, even in situations where future pathology is inevitable. This is a topic of huge debate at present.

Unfortunately the removal of third molar teeth has potential complications. These include damage to the inferior alveolar and lingual nerves, pain, swelling, infection, haemorrhage and alveolar osteitis. Damage to the inferior alveolar nerve may occur if the nerve and tooth are in close proximity. The intimate relationship of the nerve and the tooth is most commonly observed on panoral radiography. At present research into the benefits of cone beam computed tomography is underway, and shows promising results for assessing teeth in close proximity to the inferior alveolar nerve canal. There are several radiological signs visible on regular radiographs that predispose to increased likelihood of inferior alveolar nerve injury (see figure 1).5 These include:

Canal deviation

Canal narrowing

Periapical radiolucency

Narrowing of the root

Darkening of the roots

Curving of the root

Loss of canal lamina dura.5

Figure 1: Radiographic signs of increased risk to the inferior alveolar nerve.5

Nerve damage is also a potential complication, the majority of which are temporary but permanent hypoaesthesia, paraesthesia or even more worryingly dysaesthesia may occur. (See table 1 for definitions).

Table 1: Definitions of different pain pathologies.8

Research into nerve damage by Seddon and Sunderland classified five degrees of nerve injury ranging from conduction block to complete transaction of nerve fibres.9 Each of these five degrees of nerve injury may be created by wisdom tooth extraction.9 Different methods of nerve injury include; compression injuries causing neuropraxia, crush injuries inducing wallerian degeneration, stretch injuries such as that possible during lingual retraction and complete nerve sectioning.8 Injury to the nerve can occur from its compression either directly by elevators or indirectly by forces on the root during extraction.

This neurosensory deficit associated with nerve damage can cause problems with speech and mastication, which may consequently affect the patients quality of life. Third molar surgery related inferior alveolar nerve injury has been reported as temporary in up to 8% of cases, and permanent in up to 3.6%.6,7 Risk factors include increased age of patient, difficult extraction and perhaps most importantly, the proximity of the tooth to the inferior alveolar nerve canal.

Many different surgical techniques and approaches to wisdom tooth extraction exist with evidence of geographic preferences. A buccal mucoperiosteal flap is usually raised using a Howarth’s or similar periosteal elevator. Opinion varies as to whether a lingual flap should be raised. This improves visibility and involves protecting of the lingual nerve using a Howarth’s elevator or retractor. This has traditionally been the procedure of choice in the UK. It is less common in Europe and the USA where the lingual flap is not used in order to avoid possible damage to the lingual nerve. The tooth can then be sectioned if necessary to assist removal using a Cryer’s or Warwick-James elevator. Healing by primary intention is ideal, however in practice this is rarely achieved and sutures may be needed to assist healing.

Coronectomy is an alternative procedure to complete extraction and aims to remove the crown of an impacted Mandibular third molar whilst leaving the root undisturbed. It involves raising a buccal flap with subsequent removal of buccal bone down to the amelocemental junction of the tooth. The crown is then partly sectioned from the root using a fissure bur, and elevated using a suitable instrument. There is a small chance that on elevation the roots may loosen and become mobile.2 This is increasingly likely in young females, and those with conically shaped roots.2 If the roots are mobilised, they must be removed. A rose head bur should be used to remove any remaining enamel from the tooth, and the buccal flap closed using 4/0 Vicryl sutures. There is no need to medicate the pulp and antibiotics are conta-indicated. Pre- and post-operative corsodyl mouthwash, and good oral hygiene are sufficient. Alveolar osteitis is a possible post-operative complication and patients must be made aware of this and the need to seek further treatment if there is persistent pain or swelling. The tooth must be high risk, vital and the patient must not be immunocompromised.