Dental Injury

This topic featured as an SAQ back in September 2017, with the marks evenly split between risk factors (anaesthetic, patient) and management (immediate, subsequent follow-up)

Resources

Dental injury under general anaesthesia may include fracture, dislocation or avulsion of ≥1 teeth
The overall incidence is 1 in 4,500, though it is higher in cases of difficult intubation

In 90% of cases injury is to the upper incisors, typically:

During intubation or extubation (20%)
In patients with pre-existing poor-quality dentition or dental prostheses

Dental injuries account for approximately 10% of all medico-legal claims against anaesthetists

Anaesthetic risk factors

Airway-related	Operator/technique-related
Laryngoscopy and tracheal intubation	Inexperienced anaesthetic personnel
Use of airway adjuncts including LMA's, bronchoscopes, suction catheters and Magill's forceps	Inadequate depth of anaesthesia
Difficult intubation or airway maintenance	Teeth clenching during emergence
Emergency anaesthesia/RSI	Direct laryngoscopy^*

^*This isn't robustly proven

Some German anaesthetists and biomechanical engineers demonstrated that DL is indeed associated with a much higher force (20 - 30N) on the maxillary incisors than hyperangulated VL (10 - 18N), but that VL with a C-MAC made no difference (Anaesthesia, 2019)
A retrospective Singaporean study from 2018 found that use of a McGrath VL had an OR of 2.5 for dental injury, but wonder whether that was because it was used preferentially in patients deemd to be at high risk anyway
A Cochrane review from 2022 found the relative risk of dental injury compared to DL was lower with Mac-VL (0.68), hyperangulated VL (0.51) and channelled VL (0.52) but the 95%CI for each comparison crosses 1 and the collaborators themselves comment on the "very low" quality of evidence

Patient risk factors

Characteristics	Oral anatomy	Dental pathology	Drug therapy	Oral Sx of systemic dx
Obesity	Limited mandibular mobility	Previous dental injury	↓ saliva production e.g. anticholinergics, antipsychotics	Smoking
Extremes of age	Isolated or missing teeth	Caries	Sugary drugs e.g. methadone	Diabetes
Reduced neck movement	Abnormally positioned teeth	Gingival disease	↓ oral pH e.g. inhaled steroids	HIV
	Malocclusion	Peridontal disease	Gingival hypertrophy e.g. phenytoin, nifedipine	GORD/bulimia
		Bridges, caps, braces, crowns, implants	Drug therapy	Osteoporosis

Pre-operative

Pre-operative dental review ± removal of suspect teeth
Appropriate consent

Intubation

Avoid airway intervention; use regional or neuraxial technique
Avoid intubation, use an LMA
Use nasal intubation rather than oral intubation
Senior anaesthetist

Extubation

Bite-blocks inserted pre-emptively between the premolars reduces the risk of dental injury from masseter contraction during emergence

Use of OPA's are associated with dental injuries
Use of protective plastic guards intra-operatively is not evidence based

Extubate deep

Dental fracture

The loose fragment of tooth must be identified and removed from the patient's airway
If tooth not found requires CXR/CT ± bronchoscopy to exclude distal airway lodgement
Store the fragment in saline or milk as it may be suitable for bonding [the literature doesn't comment on whether semi-skimmed is adequate]

Avulsed tooth

An avulsed tooth can be immediately relocated into its socket and firm pressure applied for several minutes if the patient is not immunocompromised and the socket is healthy
Or placed in saline or milk for later re-insertion

Post-operative

Discuss with senior/consultant anaesthetic colleague
Review of pre-op assessment of dentition and intra-operative documentation
Document discussion and management in notes
Incident form complete and trust risk manager informed

Counsel the patient as to the events that occurred
Apologise
Offer analgesia
OMFS or dental review, although more usual for a patient to attend their own dentist
Follow local policies and pathways