Clinical Statistical Study on Supernumerary Teeth and Congenital Absence of Teeth

Abstract

Statistics obtained from the clinical observation of the supernumerary teeth and the congenital absence of teeth, based on the examination of our clinic are as follows :
(A) On the supernumerary teeth.
(1) The frequency of the supernumerary teeth was in 0.8% of the patients, giving a little higher degree in male than in female.
(2) Those accurrence was predominantly frequent in the anterior and premolar teeth, above all in the upper jaw.
(3) As for the state of eruption, 12 teeth (85.7%) erupted and only 2 teeth (14.3%) remained without eruption.
(4) Most of the supernumerary teeth were of rudimentary form.
(5) The abnormal displacement of the neighbouring teeth which is due to the supernumerary teeth was observed in as high as 54%.
(6) As for the combination of the other diseases, harelip and cleft palate was seen in 2 cases and schizophrenia in one case of all the eleven cases.
(B) On the congenital absence of teeth.
(1) The congenital absence of teeth was discovered in 1.44% of the patients, The occuring frequency was two times higher in female than in male.
(2) The congenital absence of teeth was seen most frequency in the anterior and premolar regio, showing little difference between upper and lower jaw as well as between right and left and it was discovered in female more than in male.
(3) 76.2 of the patients has 1 tooth missed, 9.6% 2 or 3 teeth, 4.8% 4 teeth missed.
(4) The effect on the neighbouring teeth was seen in as high as 95.2%.
(5) As for the combination of the other diseases the short frenulum linguae was discovered in only 2 cases of 21.