Double Primary Teeth in Children under 17 Years Old and Their Correlation with Permanent Successors

Background: The existence of double primary teeth associated with further problems inpermanent successors may have deleterious effects on occlusion and esthetics.The purposes of this study were to investigate the prevalence of doubleteeth in a group of Taiwanese children under 17 years old, and to comparethe distribution of the different types of double primary teeth and their relationshipto permanent successors.Methods: A total of 7868 qualified dental records of children under age 17 from thepediatric dental clinic of Chang Gung Memorial Hospital-KaohsiungMedical Center were selected for this study. Panoramic radiographs wereobtained from each child. The distribution of double teeth was investigatedaccording to sex differences, types and clinical positions. The occurrence ofdouble primary teeth and their effects on the permanent dentition were alsorecorded.Results: The prevalence of double primary teeth in children under 17 years old in thisstudy was 0.72%. Double primary teeth were found mostly in the mandibularlateral incisors and canines (63.2%). Approximately 56% of cases experiencedfurther problems in the permanent successors. Hypodontia (51.5%)was the most common problem in the permanent successors.Conclusion: The close relationship between double primary teeth and permanent successorsjustifies radiographic examination to evaluate the number and conditionof permanent successors and determine a proper treatment plan.