A study of the face recognition ability of orthodontists and lay persons of different age groups.

OBJECTIVE: To determine the face recognition ability of orthodontists and lay persons of different age groups. DESIGN: Cross-sectional study design, in which participants completed a 'Face Recognition Test'. SETTING: Participants were recruited from the Royal London Hospital, Ashford Hospital, Southend University Hospital and the British Orthodontic Society Conference, 2006. SUBJECTS AND METHOD: Colour photographs and 3D laser scans of eight volunteers were displayed and participants were asked to match the photographs of each face with the corresponding laser scan within 90 seconds. Participants consisted of 85 orthodontists under 50 years of age, 83 adolescents aged 15-18 years, 85 younger lay adults aged 19-49 years and 83 older lay adults aged 50-70 years. RESULTS: Female orthodontists were more successful in the face recognition test than female lay persons (P≤0·001) and were four times more successful than the male orthodontists (P = 0·003). There were no differences in face recognition ability between males and females in the lay persons groups (P = 0·970) or between male orthodontists and male lay persons (P = 0·240). When comparing age groups, no significant difference in successfully completing the face recognition test was detected between the adolescent, adult and older adult age groups (P = 0·070). CONCLUSIONS: Overall, our understanding of facial recognition is limited and the mechanisms by which lay people perceive and recognise other faces are important for the orthodontist to consider.

An in vitro investigation of the effectiveness of bioactive glass air-abrasion in the 'selective' removal of orthodontic resin adhesive.

The process of clinically debonding orthodontic brackets causes histomorphological damage to enamel that needs to be quantified and minimized. This study compared three methods for removing residual resin adhesive following bracket debonding. The surface finish following removal of residual adhesive using a slow-speed eight-bladed tungsten carbide bur (group 1), alumina air-abrasion (group 2), and bioactive-glass air-abrasion (group 3) and following polishing, was examined using scanning electron microscopy imaging of resin replicas. Contact profilometry was used to image surfaces before and after debonding for quantifiable volumetric analysis of enamel damage. Surface scarring was seen on scanning electron micrographs from group 1, a sharp pitted surface was identified in group 2, while group 3 exhibited similar, but subjectively smoother, pits. The surface finish following polishing was similar for groups 2 and 3 but did not completely remove the scarring evident from group 1. Quantifiable enamel lost was as follows: group 1, 0.285 mm(3); group 2, 0.386 mm(3); and group 3, 0.135 mm(3); statistical differences were observed between groups 2 and 3. From these results, bioactive-glass air-abrasion more consistently caused less physical damage to enamel and achieved a clinically smooth surface finish following polishing and is therefore to be recommended for clinical use.

Angio-oedema in dentistry: management of two cases using C1 esterase inhibitor.

UNLABELLED: Angio-oedema is a rare condition; it may be a hereditary or acquired form. It results from biochemical defects which cause excessive activation of the complement cascade and result in deep swellings in the skin and alimentary tract, called angio-oedema. These swellings are painful rather than itchy and not associated with urticaria, which helps to differentiate angio-oedema from allergic reactions. Even mild trauma can give rise to swelling, which may be life-threatening in the oral region. Management of two cases, one hereditary and the other acquired angio-oedema, are reported to demonstrate the use of C1 esterase inhibitor prophylaxis. CLINICAL RELEVANCE: It is important that patients giving a history of angio-oedema are thoroughly investigated and, in discussion with the patient's medical team, appropriate prophylactic measures are taken to prevent swelling.