Abstract
We investigated 1,946 outpatients of Nihon University Dental Hospital Department of Pediatric Dentistry, from 1978 to 1992, who had answered questionnaires on dental health control and we totaled the information in the questionnaires.
We arrived at the following conclusions.
1. With regard to the incidence of each peculiarity in males and females in total, finger sucking was seen most frequently, onychophagia was followed by mouthrespiration, and the incidence of lip biting was the lowest.
2. We divided all of the subjects into two groups to find out the recent tendencies. We compared the incidence of each peculiarity in the first group (1978-1985)with that in the second group (1986-1992). Finger sucking, mouth respiration and onychophagia tended to be seen more frequently in the second group than in the first group.
3. With regard to the duration of the period of finger sucking, the cases lasting up to three years were seen most frequently. As for onychophagia, cases lasting for one or two years were most frequently seen.
4. We examined the starting time and the ending time of the peculiarity. For finger sucking, cases in which the starting time was less than one year old were seen most frequently. There were no cases which began after six years of age. Moreover, cases in which the ending time was at three years of age were seen most frequently. With regard to onychophagia, the cases which began at three years of age were seen most frequently. The peak of the ending time ranged from four years of age to six years of age, and cases in which the ending time was after six years of age gradually decreased in number.
5. There were few connections between finger sucking and the following factors: up-bringing, the life-style or whether the mother worked. When the child lived with the grandparents, finger sucking was not so frequently seen. When the grandparents were taking care of the child chiefly, finger sucking tended to be not so frequently seen as compared to the case when the father was taking care of the child. When the father worked for a company or worked at an educational research organization, finger sucking was more frequently seen in comparison to the case when the father was self-employed or civil servant. When the child was the only child, or the middle child, finger sucking was more frequently seen in comparison to the case when the child was the eldest or the youngest in the family.
