evaluation of the occlusion and arch dimensions in the primary dentition of an iranian population

introduction: the objective of this study was to gather information about normal occlusion and arch dimensions in the primary teeth of the children belonging to an iranian population. methods: this descriptive cross-sectional study was performed on 68 children from the city of mashhad in the 3-5 age range. dental arch dimensions, interrelationships of primary canine and second molars, overbite and overjet were evaluated. results: primate space was observed on both sides of the arch in 82.2% of the subjects. the most prevalent type of primary molar relationship was flush terminal plane (52.1%) followed by distal step (31.3%) and then mesial step (16.7%). the primary canine relationship was ranked in the descending order of prevalence as class i (77.1%), class ii (13.5%), end-to-end (5.2%) and class iii (4.2%). normal overbite and normal overjet was observed in 50% and 81.3% of cases, respectively. conclusion: this study provides an insight into the dental arch dimensions, occlusion, spacing and crowding in primary dentition in iranian children. in most of the cases, primate space and flush terminal plane were observed.