Abstract
Introduction: Cephalometric analysis is a cornerstone in orthodontic diagnosis and treatment planning, enabling precise evaluation of craniofacial structures. Among the various methods, Tetragon analysis offers a unique visual approach to evaluate the maxillo-mandibular relationship. This is based on two geometric constructs, the tetragon representing the maxillo-dento-mandibular complex and the trigon, a complimentary triangle situated above it. Considering the significant genetic and environmental variations in craniofacial development, cephalometric norms established for one population may not be applicable to others.
Objective: This study aimed to establish normative cephalometric values for Tetragon analysis among Nepali adults with normal skeletal relationships.
Materials and Methods: An observational cross-sectional study was conducted using lateral cephalograms of 122 subjects (61 males and 61 females) aged 18-25 years with Class I skeletal pattern. Manual tracings were performed marking selected landmarks and planes. Angular and linear measurements were analyzed using Tetragon analysis. Descriptive statistics were calculated and gender differences for the measured variables were assessed using an independent t-test.
Results: The mean values for angular measurements of tetragon were 117.71, 124.63, 94.98, and 22.85 for upper incisor to palatal plane angle (UI-PP), interincisal angle (UI-LI), lower incisor to mandibular plane angle (LI-MP) and mandibular plane to palatal plane angle (MP-PP) respectively. Significant gender differences were observed in LI-MP and ANB measurements. Compared to other South Asian and Caucasian populations, Nepali adults showed more proclined incisors, convergent maxillary-mandibular jaw base and smaller lower facial height.
Conclusion: The upper and lower incisors tend to be more proclined and labially positioned and are relatively infraerupted with a converging tendency of the maxillary and mandibular jaw bases. Smaller lower facial height and counterclockwise rotation of the palatal plane were found in the Nepali adults.
Recommended Citation
Bhattarai, Rashmi; Shrestha, Rabindra Man; and Dhakal, Jyoti
(2025)
"Establishment of Cephalometric Norms Using Tetragon Analysis in Nepali Adults with Normal Skeletal Relationship,"
Taiwanese Journal of Orthodontics: Vol. 36:
Iss.
4, Article 2.
https://doi.org/10.38209/2708-2636.1367
Available at:
https://www.tjo.org.tw/tjo/vol36/iss4/2
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