Medico-legal importance of teeth examination

1. Estimation of age:

• Four sockets of teeth indicate a full term infant
• Eruption of milk and permanent teeth.
• Attrition of the surface of the teeth in old age.

2. Help in personal identification through presence of irregularities, crowdness, deformities, dental fillings or artificial dental plates.

3. Identification of the type and date of a crime from the site and date of the abrasions and contusions of the bite respectively. The human bite is elliptical in shape and may give identifying evidence about the shape and irregularity of the person's teeth.

4. Differentiation between human bites (2 curved rows of abrasions that meet in an elliptical form) and animal bites (2 parallel horizontal rows).
   Human bites

1. Identification of race: the teeth of the African races (e.g. Negroids) are strong, ivory white, large and in a good alignment. The upper jaw protrudes more than the lower one (prognathism) and the hard palate is less curved (flattened).
2. Careful examination of teeth may help also in diagnosis of some chronic poisoning cases by definite lines on gum margin at the root of the teeth e.g.:

• Blue black line indicates lead poisoning.

• Grey line indicates mercury poisoning.

• Green line indicates copper poisoning.

• Black line indicates bismuth poisoning.

• Yellow line indicates cadmium poisoning.

• Dirty yellowish coloration of children teeth in recurrent administration of tetracycline therapy by pregnant women.

• Arsenic deposited in enamel of the teeth which is detected chemically
  

• N.B.: Necrosis of the jaw (phossy jaw) occurs in chronic phosphorus poisoning.

Category: Forensic Medicine Notes