An Analysis of the Skeletal Relationships in a Group of Young People with Hypodontia

Abstract

The objective of this investigation was to examine the dentofacial features of a group of patients with hypodontia, in particular assessing whether cephalometric analysis confirmed the clinical assumption of a reduced lower face height, and to determine the relationship of these facial features with different numbers of missing teeth. It took the form of a cephalometric study, undertaken in a dedicated Dental Hospital clinic for patients with hypodontia. The study group comprised 59 patients seen on the Hypodontia Clinic: 32 females, 27 males, mean age 13.1+/-3.1 years (range 6-23 years). The average number of missing teeth was 7 (SD 5), ranging from 1 to 21. The mean SNA, SNB, and MMA angles were within normal limits, but there was a statistically significant reduction in the MMA when more than one tooth type was missing (P = 0.007) and the ANB angle decreased as the number of missing tooth types increased (P = 0.034). The mean values for the whole sample were within the normal range and did not demonstrate any feature specific to the group, but patients with more severe hypodontia showed tendencies to a Class III skeletal relationship and a reduced maxillary-mandibular planes angle.

Craniofacial morphology in individuals with increasing severity of hypodontia

“…In the present study, all three hypodontia groups showed a significant reduction in the SNB angle compared with the controls. This disagree with the findings of Wisth et al, 27 Nodal et al, 30 Chung et al 31 and Yüksel and Ucem, 36 who founds no changes in SNB, but confirms those of Bondarets and Mc Donald, 24 who showed decreased SNB angle in persons with hypodontia. In individuals with agenesis persist continued reductions of values of ANB angle.…”

“…A decrease in vertical jaw relation and mandibular plane inclination in persons with severe hypodontia was observed by Øgaard and Krogstad 25 and Nodal et al 30 Chung et al 31 and Acharya et al 32 found that severe hypodontia had a significant effect on a skeletal relationship.…”

“…However, only a few authors have investigated the influence of different numbers of missing teeth on craniofacial morphology. 24,25,[30][31][32] Bondarets and Mc Donald 24 found that individuals with severe hypodontia had the typical facial characteristics unique to hypodontia, with reduced vertical dimensions.…”

“…[25][26][27]31,32 The ANB angle decreased as number of missing teeth increased, and the patients with more severe hypodontia showed tendencies to a Class III skeletal relationship. 31,32 Increasing numbers of missing teeth resulted also in a decrease in the length of maxilla, what is consistency with the findings of Wisth et al 27 and Woodworth et al 23 According to Roald et al, 35 the absence of permanent tooth buds may have a negative influence on the magnitude of growth in the maxilla, which results in reduced maxillary length. There are opposite opinions in the literature for the length of mandible.…”

“…24,25,[30][31][32] Ogaard and Krogstad 25 concluded that typical dentofacial structure in individuals with a larger number of absent teeth, is due to dental and functional adjustment rather than to an altered growth pattern, but Bondarets and Mc Donald, 24 in Table 2. Significantly reduced value of SNA angle in patients with different number of absent teeth determined in this study, is in compliance with findings of Wisth et al, 27 Roald et al, 35 Sarnäs and Rune 26 and Ogaard and Krogstad, 25 opposite to normal values of this parameter established of Woodworth et al, 23 Nodal et al, 30 Chung et al 31 and Yüksel and Ucem. 36 Published results on the mandibular effects of hypodontia vary.…”