CORONAL MORPHOLOGY OF THE MANDIBULAR 2ND PREMOLAR IN THE SINGAPOREAN CHINESE

Five hundred and sixty-four patients of Singaporean Chinese origin wit h bilateral second premolars present were screened. Morphological feat ures of the crown, number and position of cusps and the sex of the pat ient were recorded. The mesio-distal dimensions of the cro ns were mea sured. Three hundred and seventy-four (66.3 per cent) exhibited bilate ral 2-cusp forms; 143 (25.4 per cent) were 3-cusp forms; and 47 (8.3 p er cent) were mixed. There was no sex predilection in the three groups . In the 2-cusp forms, the predominant occlusal pattern was H-shaped ( 75.9 per cent). The 3-cusp type with a Y-shaped pattern and a squarish outline is a significant morphological and racial characteristic in t he local population. The presence of 2-cusp and 3-cusp forms in an ind ividual is an unusual developmental phenomenon.