A prospective study concerning with the transmission of mutans streptococci from mother to infant

2002 Fiscal Year Final Research Report Summary

• Project/Area Number: 12672010
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 矯正・小児・社会系歯学
• Research Institution: Iwate Medical University
• Principal Investigator: ABE Akiko Iwate Medical University Assistant, 歯学部, 助手 (90185992)
• Co-Investigator(Kenkyū-buntansha): INABA Daisuke Iwate Medical University Assistant professor, 歯学部, 助教授 (90146085) ; KISHI Mituo Iwate Medical University lecturer, 歯学部, 講師 (60295988) ; AIZAWA Fumie Iwate Medical University Assistant, 歯学部, 助手 (80216754) ; YONEMITU Masami Iwate Medical University Professor, 歯学部, 教授 (80092451)
• Project Period (FY): 2000 – 2002
• Keywords: Mutans streptococci / Colonization / Dental caries / Childcare

Research Abstract

We attempted to clarify when mutans streptococci were colonized in Japanese infants' oral cavities, and to analyze what factors related to the occasion of dental caries in 30 months old infants. 71 infants were surveyed at the age of 12 months, 18 months and 30 months, in a town of Iwate prefecture, Japan. In each point of survey, we examined their dentitions, and obtained their dental plaque and sliva samples. Prior to the examination, their mothers had completed a questionnaire containing the questions about daily habits of dietary behavior and oral hygiene in the child care at the time, and we recovered it on the day of examination. To know the mother's experience of dental caries and level of mutans streptococci, we carried out the dental examinations for them and collected their sliva samples at the start of this study. The colonization of mutans streptococci was found in 21.1% of 12 months old infants. Afterwards, the colonization rate increased to 35.2% at the age of 18 months, and 54.9% at the age of 30 months. And 21.1% of the infants had one or more tooth suffering from dental caries at the age of 30 months. A logistic regression analysis showed the significant factors relating to the occurrence of dental caries at the age of 30 months. Those were taking sugar contained drinks with feeding bottle, sharing the tableware in parent and child, and the colonization of mutans streptococci in the age of 12 months. Further, in the age of 18 months, the colonization of mutans streptococci was significant factors even in the age, and daily toothbrushing by the mother was found as a factor could reduce the occasion of dental caries.