title: Assessment of 2D:4D in subjects with anteroposterior mandibular dysplasia.
abstract: OBJECTIVE
  To compare 2D:4D ratio which is determined by testosterone levels with patients having orthognathic, retrognathic and prognathic mandibles.
  
  
  METHODS
  The study was performed at Chennai, on 320 subjects of which, 60 subjects (32 males and 28 females) had retrognathic mandible; 55 subjects (25 males and 30 females) had prognathic mandible and 205 subjects (98 males and 107 females) had normal mandible. All the subjects had a normal maxilla and were in the age group of 18 to 25 years. 2D:4D ratio was determined using the photocopies of the ventral surface of right hand made with vernier calipers of 0.01 mm accuracy. Statistical analysis was undertaken using Student's t- test, ANOVA test and TukeyHSD test.
  
  
  RESULTS
  (i) Low 2D:4D is seen in subjects with mandibular prognathism, (ii) Among females, low 2D:4D is seen only in prognathic mandible.
  
  
  CONCLUSIONS
  These findings highlight the fact that testosterone plays an important role in mandibular growth. Thus 2D:4D, a least invasive and reproducible procedure can be used as an early marker for mandibular progathism, and as a diagnostic tool in correlating the mandibular growth with causal relations between hormones and craniofacial development.
authors.affiliation: Professor, Department of Orthodontics, Tamil Nadu Government Dental College and Hospital, Chennai, Tamil Nadu, India e-mail: dr_premsridhar@yahoo.co.in.
authors.forename: Sridhar
authors.initials: S
authors.lastname: Premkumar
authors.forename: Bhuvaneswari
authors.initials: B
authors.lastname: Gurumurthy
mesh_terms: D000293:Adolescent; D000328:Adult; D001837:Body Weights and Measures; D002508:Cephalometry / Q000379:methods; D005260:Female; D005385:Fingers / Q000033:anatomy & histology*; D006801:Humans; D008297:Male; D008311:Malocclusion, Angle Class I / Q000473:pathology; D008312:Malocclusion, Angle Class II / Q000473:pathology; D008313:Malocclusion, Angle Class III / Q000473:pathology; D008334:Mandible / Q000254:growth & development / Q000473:pathology; D009295:Nasal Bone / Q000473:pathology; D011378:Prognathism / Q000473:pathology*; D063173:Retrognathia / Q000473:pathology*; D012658:Sella Turcica / Q000473:pathology; D012737:Sex Factors; D055815:Young Adult