Biometric analysis of the dental arches and teeth position in partially edentulous patients

Abstract

An edentulous state often causes changes in the dental arch shape first in the defect area, and then spreads to the entire dental arch. Secondary deformities of the tooth arches, which occur during pathological displacement of individual teeth, considerably complicate the clinical picture with partial tooth loss. The objective of the work is to study the dental arch size and teeth position in the defect area in sagittal and transversal planes in adult partially edentulous patients. Materials and methods. 32 partially edentulous patients aged from 20 to 60 years and older were examined. The diagnosis was based on Kennedy's classification. The dental arches size was determined by the methods of Pont and Korkhaus; the occlusal curve of Spee, contact angles and tooth angulation were assessed by diagnostic gypsum models (32 pairs). The patients were divided into 3 groups: Group 1 – 5 persons with defects only of the upper dental arch; Group 2 – 13 patients with defects only of the lower dental arch; Group 3 – 14 patients with defects of both upper and lower dental arch. Results. The measurements of diagnostic models by Pont and Korkhaus methods indicated an active influence of dental arch defects on deformation of both dental arches: due to their narrowing or expansion in the transversal plane and elongation or shortening in the sagittal one. The upper dental arch defects had lesser influence on a change in dentition width, while the lower dental arch defects 4 times more actively promoted the progression of dentition deformation and the presence of both jaw defects was accompanied by the dentition deformation in all the cases. The presence of a dental arch defect even in one jaw affected a change in the dentition length within both jaws. The Spee curve intensity was significantly increased among patients with defects of both dental arches. Normal indicators of the contact angles and tooth angulation values in the area of dental defects were not revealed among the patients of all groups. The lower dental arch defects presence had a greater effect on a change in the tooth contact angles than the upper dental arch defects presence. The degree of the values deviation from the normal angulation significantly exceeded the degree of the tooth contact angles deviation values. Conclusions. The measurements of the width and length of dental arches using diagnostic models of partially edentulous patients indicated the deformation of both dental arches in the transversal and sagittal planes due to their narrowing or expansion, elongation or shortening. All the patients with dental defects had changes in length, predominantly an elongation, in the anterior region of the dental arch. The occlusal plane in the partially edentulous patients was deformed. The deep occlusal curve was mostly determined. There was a displacement of the teeth among all the partially edentulous patients. This displacement limited the defect in mesiodistal / mediolateral (angulation) and vestibular-oral (contact angles) direction.

Keywords

• dentition
• spee curve
• dental contact angles
• dental angulation