## 4 Discussion
\begin{table}
\begin{tabular}{c c c c} \hline
**Measurements** & **F-Value** & \(p\)**-Value** & **Pairwise Comparison** \\ \hline \multirow{3}{*}{NA-APo (\({}^{\circ}\))} & \multirow{3}{*}{0.8} & \multirow{3}{*}{0.6021} \\  & & & 1 \(<\) 3, 1 \(<\) 7, 1 \(>\) 5, 2 \(<\) 3, 2 \(<\) 4, 2 \(<\) 7, 2 \(>\) 5, 2 \(<\) 9, 3 \(>\) 4, \\ \multirow{3}{*}{FH-NFo (\({}^{\circ}\))} & \multirow{3}{*}{15.05} & \multirow{3}{*}{\textless{}0.0001} & 3 \(>\) 8, 3 \(>\) 5, 3 \(>\) 6, 3 \(>\) 9, 4 \(>\) 8, 4 \(>\) 5, 4 \(>\) 6, 7 \(>\) 8, 7 \(>\) 5, \\  & & & 7 \(>\) 6, 8 \(>\) 5, 6 \(<\) 5 \(>\) 9, 6 \(<\) 9 \\ \hline \end{tabular}  
* 1: Orthodontist, 2: orthodontist/AI, 3: resident, 4: resident/AI, 5: dentist, 6: dentist/AI, 7: student, 8: student/AI, 9: AI.  
\end{table} 
Table 4: _Cont._significant reduction in accuracy in U1-NA (mm) compared to other measurements and theorized it may be due to superimposition of surrounding anatomy [11]. In terms of accuracy averaged among all the examiners, 13 of the 26 measurements demonstrated MAEs greater than 2 mm or degrees without the use of AI. The increased MAEs of FMA and posterior face height may be due to the difficulty of identification of the gonion landmark. Gonion is a constructed point that relies on accurate identification of other landmarks, such as articulare and menton, to create tangent lines to the inferior body of the mandible and posterior border of the ramus. Slight inaccuracies in the tangent lines can dramatically affect the location of gonion. Among the 16 landmarks evaluated by [PERSON] and [PERSON], gonion was found to be the least reliable landmark in both the x and y-axes in lateral cephalometric films [20]. Additionally, in the case of FMA, it is possible that the orbitale landmark was not accurately identified by all examiners. Orbitale has been shown to have significant variability in lateral cephalometric identification, especially in the y-axis [21]. Inaccuracy of the maxillary length measurement may be due to difficulty of identification of the posterior nasal spine landmark, as it is often superimposed with the third molar germ. Condylion and basion landmarks are also challenging to identify due to the superimposition of other craniofacial structures and thus may explain the higher MAEs of mandibular length and cranial base angle. Basion has shown significant variation in identification in both the x and y-coordinates [21]. The incisor angulation measurements (U1-SN, U1-NA, L1-MP, L1-NB, and interincisal angle) also demonstrated increased MAEs. This could be due to difficulty in the identification of upper and lower incisor apices. [PERSON] and [PERSON] found that upper and lower incisor apices were not reproducibly identified in 75% of cases [22]. Misidentification of the incisor root apices results in alterations of the long axis of the upper and lower incisors, which affects the accuracy of U1-SN, U1-NA, L1-MP, L1-NB, and interincisal angles. The AI/human augmentation method was a novel aspect of this study. This method demonstrated an increase in the precision and accuracy of all examiner groups compared to the manual landmark identification technique, especially with the less experienced student and dentist examiners. This is likely due to the inherent ability of the AI to predictably locate each landmark in a nearly identical position [9]. The less experienced examiners may not have changed the position of landmarks unless there was a significant discrepancy due to a lack of skill in tracing lateral cephalometric radiographs. Most measurements that showed clinical significance overlapped between AI alone and the AI/human augmentation method (posterior face height, FMA, L1-MP, L1-NB, and interincisal angles). This reinforces the idea that the location of difficult to locate landmarks, such as gonion and incisor apices, may not have been modified by examiners. Overall, the results from this study show that the human/AI augmentation method demonstrates greater accuracy and precision for all examiner groups compared to manual landmark identification.