Aim: To determine the prevalence of oral habits and its association with certain parameters (age, gender, child rank in the family, mother education and feeding type and duration) and the effect of oral habits on the occlusion of primary dentition. Methods: A cross-sectional study throuPankaj Datta, gh questionnaire and clinical examination for 489 preschool Sudanese children 3-5 years old, from randomly selected kindergartens in Khartoum. Results: Prevalence of oral habits was found to be 30.3%. Thumb sucking was the most prevalent one. No significant associations were found between oral habits, age and gender. A significant association were found between oral habits and rank of the child in the family as well with mother education level and breast feeding (P<0.05). A higher prevalence of open bite, increased overjet, distal molar relation, Class II canine relation, and posterior cross bite were found among children with existing oral habits. Conclusion: Sudanese preschoolers had  high prevalence of oral habits and persistent of oral habits after the age of three years has side effect on the primary occlusion, so early recognition of oral habits and proper education program for parents and children are recommended to prevent and intercept the occurrence of malocclusion in the permanent dentition.   

Keyword: Oral Habits; Thumb Sucking; Nail Biting; Breast Feeding.