Cephalometric features of skeletal Class I, II and III (A comparative study)

Abstract

Aims: To identify the cephalometric features of three skeletal jaw relations (Class I, II and III). Materials and methods: one hundred thirty four students were selected aged 12-15 years from secondary schools in Mosul City, 45 with Class I normal occlusion as control, 44 with Class II malocclusion and 45 with Class III malocclusion, after taking the lateral cephalometric radiographs according to ANB angle. A 20 variables (12 angular and 8 linear) were used in this study to correlate these variables in the three skeletal Classes. Results: No significant sex differences were observed for the majority of angular and linear measurements for the three skeletal types. Anterior cranial base length (S-N) and saddle angle (NSAr) didn't show significant difference among the three skeletal Classes, the posterior cranial base (S-Ar) was shorter in Class III which indicate the anterior articulation of the mandible. The length of maxillary base (ANS-PNS) was longer in Class II than Class I and III which lead to maxillary prognathism. The body length of the mandible (Go-Pog),effective mandibular length (Ar-Gn) and lower anterior face height was significantly longer in Class III which lead to mandibular prognathism. The SNA angle was significantly smaller in Class III than in the others. SNB and SNPog angles were larger in Class III followed by Class I and then Class II. The gonial angle (Ar-Go-Me) was larger in Class III which acts to increase mandibular effective length. The (N-A-Pog) showed as convex in Class II and concave in Class III. (The U1-PP) angle was larger in Class II followed by Class I and then by Class III. The (L1-MP) angle in Class II and III was significantly smaller than in Class I. Conclusion: Most of the angular and linear measurements indicated that the skeletal differences between the Class I, Class II and Class III are concentrated with in the maxillary and mandibular bases in both the anteroposterior and vertical dimensions and their type of articulation. The dental measurements appear to be compensated with that of skeletal one. Also these variables showed no significant sex differences in the majority of their measurements.

Cranial base measurements in different anteroposterior skeletal relationships using Bjork-Jarabak analysis

“…Gonial angle was larger in Class III compared with the Class II skeletal relationship. This was supported by the findings of Gasgoos et al, 29 who found that the gonial angle was larger in the Class III group. Those authors suggested that the increase in the gonial angle resulted from the increase in the effective length of the mandible (Ar-Gn).…”

“…This agreed with the findings of previous studies that reported a longer mandible in Class III cases. 29,34,35 No differences were found in angular measurements between men and women except for articular angle. This was supported by previous findings of Rodriguez-Cardenas et al, 28 who reported that the articular angle was increased in female patients.…”

“…This was supported by the findings of a previous study. 5 Gasgoos et al 29 also found that subjects with a Class III skeletal relationship had a larger mandibular body length (Go-Pog) and larger effective mandibular length (Ar-Gn) than Class II subjects.…”

A Comparative Assessment of the Upper Pharyngeal Airway Dimensions among Different Anteroposterior Skeletal Patterns in 7–14-Year-Old Children: A Cephalometric Study

“…However, the skeletal patterns did not affect the SNA values in our study. Our results agreed with those of a previous study [ 35 ].…”

Metode Pengukuran Sudut Gonial Antar Pola Vertikal Skeletal Pada Sefalometri Lateral

“…2,7 Pada tiap kelompok pola vertikal skeletal, tidak ditemukan perbedaan yang signifikan antara melaporkan bahwa sudut gonial pada kasus maloklusi kelas III lebih besar daripada kelas I dan II. 32 Penelitian oleh Jacob dan Buschang menemukan bahwa sudut gonial pada maloklusi kelas II lebih kecil daripada kelas I akibat defisiensi pertumbuhan kondilus. 33 Selain itu ul-Haq et al tidak membedakan hasil sudut gonial antara usia growing dan non growing seperti kriteria inklusi penelitian ini yang hanya mengambil sampel dengan rentang usia non growing, yaitu 17-35 tahun.…”