Medical assessor guidance note 15

Ear, nose and throat and related structures impairment

Assessment of dental injuries: loss of teeth and potential loss of structural integrity of the face.


This material is issued by the Motor Accidents Authority under s65 (2) of the Motor Accidents Compensation Act 1999 (the Act) in the interests of promoting accurate and consistent medical assessments under the Act. The interpretation provided here is not legally binding but represents the clinically recommended interpretation in an area where more than one interpretation of existing provisions may be possible. This recommended interpretation is publically available. Any medical assessment which does not adopt this interpretation should be accompanied by clinical justification for the interpretation adopted, supported by full, robust reasons.


  • The Motor Accidents Authority Permanent Impairment Guidelines – Guidelines for the assessment of permanent impairment of a person injured as a result of a motor vehicle accident 1 October 2007 (MAA Guidelines): Chapter 6 Teeth, paragraphs 6.18-6.21 (page 37).
  • The American Medical Association Guides to the Evaluation of Permanent Impairment, 4th Edition (AMA 4 Guides): Chapter 9 Section 9.3b, Mastication and Deglutition (page 231); and Chapter 9 section 9.2 The Face (page 229-30).


Currently, the majority of dental injuries are assessed in accordance with Chapter 6, Teeth, of the MAA Guidelines and Chapter 9, section 9.3b Mastication and Deglutition, of the AMA 4 Guides.

Issues requiring clarification

The AMA 4 Guides provide that ‘In evaluation of permanent impairment from a disorder of the face, functional capacity as well as structural integrity should be considered’ (9.2 The Face page 229).

Dental injuries may result in more than one assessable impairment. A dental injury or injuries may cause a loss of functional capacity and a loss of structural integrity.

When functional capacity (mastication or deglutition) is impaired, the imposition of dietary restrictions usually results. Such restrictions are the most objective criteria by which to evaluate permanent impairment of these functions (9.3b Mastication and Deglutition AMA 4 Guides page 231).

Loss of structural integrity (loss of supporting structures such as soft tissue, teeth, bone or cartilage of the facial skeleton) may result in cosmetic deformity (9.2 The Face AMA 4 Guides page 229).

Preferred approach

Prior to making any determination, Medical Assessors should consider the advice provided in the MAA Guidelines at clause 1.32 'Adjustments for the effects of prostheses or assistive devices' and whether the claimant advises that they are/are not planning to undertake future treatment. For example, where a claimant wears a plate/partial denture for the loss of several teeth as a result of the motor accident, the denture should be removed to determine any dietary restrictions and to determine any loss of structural integrity.

An impairment figure may be assigned by a Medical Assessor assessing the dental injury based on the claimant’s dietary restrictions, if any, in accordance with Table 6 AMA 4 Guides (page 231) and as modified by the MAA Guidelines clause 6.20 (page 37).

An impairment figure may be assigned by a Medical Assessor assessing the skin and scarring or facial injury based on a loss of supporting structures of the face in accordance with section 9.2 ‘The Face’ ‘Criteria for Facial Impairment’ Class 2 Impairment of the Whole Person 5-10% AMA 4 Guides (page 229).

Any impairment figures are combined.

Where the injury is referred to a Medical Assessor who is a dentist (or otherwise suitably qualified to assess the dental injury) and the injury has not resulted in any loss of structural integrity to the face, the Assessor should indicate that the issue has been addressed and that there is no assessable impairment for loss of structural integrity to the face.

Alternatively, where the injury is referred to a Medical Assessor who is a dentist (or otherwise suitably qualified to assess the dental injury) and, in their opinion, the injury may have resulted in a loss of structural integrity to the face, the injury should be referred to a suitably qualified Medical Assessor to assess the skin and scarring or facial injury.

Justification for preferred interpretation

This approach would ensure any functional loss (mastication) and any disfigurement are both considered when assessing permanent impairment. The preferred interpretation is suggested to promote consistency of assessment.

Issued by:

Injury Strategy Branch

April 2014