[Root canal morphology of deciduous tooth].

OBJECTIVE: To find out the morphological regularity of root canal in the primary tooth. METHODS: Through transparent specimen of a set of deciduous teeth, the shape of root canal was observed under stereomicroscope. RESULTS: Among the deciduous anterior teeth, 92% were single canal except for one single-double mixed canal. Maxillary deci-duous molar had 3 canals and mandibular deciduous molar had 4 canals, lateral canal and anastomosis between the root canals were popular in deciduous molar. CONCLUSION: Deciduous root canal morphology is simple in anterior teeth and comparatively complex in molar.

Age-related changes in pulp cavity of incisors as a determinant for forensic age identification.

To find a simple and convenient method for age identification upon age-related pulp cavity narrowing, the mesiodistal diameters of the cervical pulp chamber, the middle and terminal parts of the root canal of the pulp cavity of 620 incisors were measured on radiographs taken in situ in 80 Chinese aged from 15 to 80. It was shown that the three mesiodistal diameters significantly decreased in a negative linear relationship with age (-0.4233 ≤ r ≥ -0.8465) in all incisors, but the narrowing velocity of the cervical pulp chamber and the middle part of the root canal in the maxillary incisors (b = -0.02 mm) was faster than that in the mandibular incisors (b = -0.01 mm). Accordingly, a mathematical model describing the ages as a function of any one of the three mesiodistal diameters of the pulp cavity was deduced, which would be useful for age identification in forensic medicine or archaeology.