Objective: The aim of the present study was to estimate the amount of overlap in children with the primary dentition. Study design: The sample consisted of 20 Japanese boys between 3 and 5 years of age (mean age:4years 10 months). Landmarks on their maxillary and mandibular dental models were digitized using a three-dimensional mechanical digitizer in a single coordinate system. Multilevel statistical models created best-fit polynomial curves to determine overbite, overjet and buccal height of all primary teeth and describe the dental arch forms. Results: No significant side differences were detected. The primary canine showed the largest overbite (1.87 mm) and buccal height (9.07 mm). The primary second molar exhibited the largest ovejet (2.76 mm). Buccal height was the least variable measurement. Conclusion: Occlusal relationships of the primary dentition were evaluated in 3-dimensions, establishing overlap variables for clinical diagnosis and treatment planning.