The Influence of Facial Parameters on Orthognathic Patient, Layperson and Clinician Perceived Attractiveness

    Student thesis: Doctoral ThesisDoctor of Philosophy


    Purpose: To undertake an objective and quantitative evaluation of how the variation of facial parameters influences perceived attractiveness.
    Part 1 (chapter 3): The craniofacial height of an idealized image was altered from 1/6 to 1/10 of standing height, creating 10 images shown in random order to 89 observers (74 laypeople; 15 clinicians), who ranked the images from most to least attractive.
    Part 2 (chapters 4-8): Assessing the influence of lower facial parameters on perceived attractiveness.
    Idealized facial images were created. Specific parameters were incrementally altered, creating a range of images, rated on a Likert scale by 185 observers: pre-treatment orthognathic patients (n=75), laypeople (n=75) and clinicians (n=35).
    Part 3 (chapter 9): A longitudinal study assessing the effects of orthognathic surgery on perceptions of attractiveness. The images from chapter 8 were rated by 50 orthognathic patients at T1 (pre-treatment) and T2 (6-months following debond).
    Part 1: A proportion of 1/7.5 was perceived as the most attractive (range: 1/7 to 1/8.5). Images perceived as most unattractive had a proportion of 1/6 and 1/10.
    Part 2:
    Chin height: The classical lower facial canon may be used as an ‘ideal’ proportional ratio. Variations within a given range were largely unnoticed, i.e. between 30% chin to lower anterior face height (LAFH) (male and female), up to 40% (males) and 50% (females). Surgery was desired with greater variations in chin height: >50% and <20-23% of LAFH (males), >58% and <20-22% of LAFH (females). Clinician and patient ratings were similar and more critical than laypeople.
    Mandibular and chin point asymmetry: 10-mm is perceived as significant; at 5-mm and below, it is largely unnoticed. The greater the degree of asymmetry above 10-mm, the greater the desire for correction. Clinician and patient ratings were similar and more critical than laypeople.
    Lower face convexity: A straight profile is perceived as most attractive and greater degrees of convexity or concavity deemed progressively less attractive. A range of 10°
    to -12° may be acceptable; beyond these values surgical correction is desired. Patients are most critical, and clinicians are more critical than laypeople.
    Chin prominence: An ‘ideal’ sagittal position with soft tissue pogonion on or just behind a true vertical line through subnasale may be used. Retrusion or protrusion up to 4-mm is unnoticeable. Surgery is desired for protrusions greater than 6-mm and retrusions greater than 10-mm. The overall direction of aesthetic opinion appears to be the same for all observer groups.
    Mandibular prominence: Retrusion up to −4 mm or protrusion up to 2-mm was unnoticeable. Surgery was desired from protrusions of greater than 3 mm (patients and laypeople) and 5-mm (clinicians) and retrusions greater than −8 mm. The overall direction of aesthetic opinion was the same for all the observer groups, but patients were more critical than laypeople.
    Part 3: There was little change in perception between T1 and T2. The process of orthognathic treatment does not appear to have any significant effect on patients’ perceptions of facial profile attractiveness or the limits of mandibular sagittal deviation at which they would desire surgery.
    Date of Award1 Feb 2013
    Original languageEnglish
    Awarding Institution
    • King's College London
    SupervisorMartyn Cobourne (Supervisor), Fraser McDonald (Supervisor) & Nora Donaldson (Supervisor)

    Cite this