Our purpose was to determine in 20 unilateral cleft lip and alveolus subjects characteristics of the maxillary permanent teeth and maxillary arch development. Clinical and radiographic examinations have been carried out to identify congenitally missing teeth and sagittal skeletal patterns. Study cast assessment was undertaken to evaluate mesiodistal widths of individual teeth, intercanine and intermolar distances for the maxillary arch, as well as dental relationships. We observed that the congenital absence of the upper incisors was higher on the cleft side than on the non-cleft side. There was a statistically significant difference between the mesiodistal widths of cleft-side permanent upper lateral incisors, and their antimeres (p<0.05). Most of the patients presented a class II dental relationship on the affected side comparing to class I/class III Angle on the unaffected side. We concluded that patients with isolated cleft lip and alveolus present perturbations in dental and maxillary arch development, a more severe disruption being recorded on the cleft side.