Evaluation of the Depth of the Curve of Spee in Untreated Orthodontic Patients in the University of Benin Teaching Hospital, Benin City, Nigeria

Abstract

Objective: Curve of Spee is a naturally occurring curve of the occlusal plane in the human dentition which begins at the tips of the  incisors following the buccal cusps of the premolars and molars and continuing to the anterior border of the ramus, and it plays several  roles in human dentition. The aim of this study was to evaluate the depth of Curve of Spee in untreated Orthodontic patients in Benin City, Nigeria.

Methods: Dental casts of 100 untreated orthodontic patients were selected and classified using Angle’s method. Using a digital caliper  (European Directive ROHS 2002/95/CE) the depth of curve of Spee was measured as the perpendicular distance between the deepest  cusp tip and a flat plane that was laid on the occlusal surface of the maxillary and mandibular dental casts, touching the incisal edges of the central incisor and the most distal cusp of the most posterior teeth in the upper and lower arches. The data was computed with SPSS  version 21.0 and analyzed for frequencies, percentages and means. Variations between variables were evaluated with the Chi-square test. P values at < 0.05 were set as significant.

Results: The mean depth of the curve of Spee in the mandibular arch on the right side was 2.4± 0.90 mm, while on the left side it was 2.3  ± 1.0 mm. The average depth of the mandibular curve of Spee was 2.3 ± 0.8 mm. The mean depth of the curve of Spee in the maxillary  arch on the right side was 2.6 ± 1.3 mm, while on the left side it was 2.6 ± 1.2 mm. The average depth of the maxillary curve of Spee was 2.6 ± 1.2 mm. The depth of the curve of Spee in the maxillary arch was greater than the value obtained for the mandibular arch, but not  statistically significant (P=0.05). 

Conclusion: This study recorded higher values in depth of curve of Spee in the maxillary arch when  compared to the mandibular arch. The difference was not statistically significant.