Background Growth and development of the dental arch is considered a continuous and complex biological process. During transition from primary to mixed then to permanent dentition, dental arch form, length and width vary, due to tooth movement and vertical growth of alveolar process. These naturally occurring changes, which happen in untreated individuals, have been used as a comparative standard to assist in diagnosis and treatment planning of children with malocclusion. Therefore, the aim of the current study was to analyze dental arch dimensions in Egyptian children and adolescents with normal occlusion in primary, mixed, and permanent dentitions as well as detection of the most common forms of the dental arches among a group of Egyptian children and adolescents. Results Results showed that lower and upper arch lengths showed increase during transition from mixed to permanent dentition. A small increase in lower anterior arch length was recorded during transition from primary (4.63) to mixed dentition (4.70), while reduction of upper anterior arch length was observed during transition from primary (8.35) to mixed dentitions. An increase in anterior arch length was observed in both arches during transition from mixed to permanent dentitions (from 4.70 to 5.42 in the mandible and from7.92 to 9.90 in the maxilla). Arch perimeter, intercanine width, intermolar width increased in the upper and lower arches during transition between dentition till reaching the permanent dentition. It was also found that the ovoid arch form (58%) and square arch form (29%) were the most prevalent among Egyptian children and adolescents followed by the tapered arch form (13%). Conclusions Dental arch measurements of Egyptian children and adolescents can be used as a guide for treatment planning of Egyptian children and can be used in further studies to provide standard values for the arch dimensions of the Egyptian children. Regarding the arch form, the ovoid arch form was the most common among the Egyptian population followed by the square while the tapered arch form was the least common one.

Aim: The present study was conducted to determine the correlation between the combined mesiodistal width of teeth, arch length and arch perimeter in a sample of the Egyptian population.Material and methods: Four hundred and twenty pairs of dental casts were traced using TracerNet. The combined mesiodistal width of teeth (CMWT), arch length (AL) and arch perimeter (AP) were measured. Statistical analysis was conducted utilizing Pearson correlation and paired t-test.Results: The results showed a significant positive correlation in the lower arch between the AP and the AL, the CMWT and AL; p<0.05. There were no significant correlations in the upper arch. There was significant difference between the ratio of the upper and lower AP to CMWT; p=0.00.Conclusions: There were positive correlations between the arch perimeter and arch length, combined mesiodistal width of teeth and the arch length in the lower arch, with no correlation between the arch perimeter and the combined mesiodistal width of teeth. Therefore, during orthodontic diagnosis and treatment planning a thought should be given to treatment options that do not involve reduction of tooth mass. The measured values of the different variables could act as a database describing the tooth width and arch dimensions of the representative sample.