Comparative Evaluation of Five Alternative Methods for Estimation of Point A with Different Maxillary Incisor Inclinations: A Cephalometric Study

International Journal of Dental Science and Innovative Research (IJDSIR) IJDSIR : Dental Publication Service Available Online at:www.ijdsir.com Volume – 8, Issue – 4, August – 2025, Page No. : 121 - 149 Corresponding Author: Dr. Mehak, ijdsir, Volume – 8 Issue - 4, Page No. : 121 - 149 Page121 ISSN: 2581-5989 PubMed - National Library of Medicine - ID: 101738774 Comparative Evaluation of Five Alternative Methods for Estimation of Point A with Different Maxillary Incisor Inclinations: A Cephalometric Study 1Dr. Mehak, PG 3rd Year, Department of Orthodontics and Dentofacial Orthopaedics, Guru Nanak Dev Dental College and Research Institute, Sunam, Punjab. 2Dr. Parul Jain, Professor and HOD, Department of Orthodontics and Dentofacial Orthopaedics, Guru Nanak Dev Dental College and Research Institute, Sunam, Punjab. 3Dr. Abhishek Sharma, Professor, Department of Orthodontics and Dentofacial Orthopaedics, Guru Nanak Dev Dental College and Research Institute, Sunam, Punjab. 4Dr. Atul Jindal, Reader, Department of Orthodontics and Dentofacial Orthopaedics, Guru Nanak Dev Dental College and Research Institute, Sunam, Punjab. 5Dr. Ushmita Mehta, Senior Lecturer, Department of Orthodontics and Dentofacial Orthopaedics, Guru Nanak Dev Dental College and Research Institute, Sunam, Punjab. 6Dr. Mohammed Ismail, Postgraduate, Department of Orthodontics and Dentofacial Orthopaedics, Guru Nanak Dev Dental College and Research Institute, Sunam, Punjab. Corresponding Author: Dr. Mehak, PG 3rd Year, Department of Orthodontics and Dentofacial Orthopaedics, Guru Nanak Dev Dental College and Research Institute, Sunam, Punjab. Citation of this Article: Dr. Mehak, Dr. Parul Jain, Dr. Abhishek Sharma, Dr. Atul Jindal, Dr. Ushmita Mehta, Dr. Mohammed Ismail, “Comparative Evaluation of Five Alternative Methods for Estimation of Point A with Different Maxillary Incisor Inclinations: A Cephalometric Study”, IJDSIRAugust – 2025, Volume – 8, Issue – 4, P. No. 121 – 149. Copyright: © 2025, Dr. Mehak, et al. This is an open access journal and article distributed under the terms of the creative common’s attribution non-commercial License. Which allows others to remix, tweak, and build upon the work noncommercially, as long as appropriate credit is given, and the new creations are licensed under the identical terms. Type of Publication: Original Research Article Conflicts of Interest: Nil Abstract Objective: This study aimed to evaluate the reliability of five alternative cephalometric landmarks (A1–A5) as substitutes for Point A across varying maxillary incisor inclinations—normally inclined, proclined, and retroclined—using angular and linear cephalometric parameters. Materials and Methods: A total of 120 pretreatment lateral cephalograms were analyzed and divided into three groups (40 each) based on U1-PP angulation. Point A (Downs) and five alternatives—A1 (Jacobson), A2 (Tindlund), A3 (Prosthion projection), A4 (Labial lamella), and A5 (2 mm anterior to apex)—were identified on each radiograph. Angular (SNA, U1–NA, N–A–Pog) and linear (NA–P, U1–NA) measurements Dr. Mehak, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page122 Page122 Page122 Page122 Page122 Page122 Page122 Page122 Page122 Page122 Page122 Page122 Page122 Page122 Page122 Page122 Page122 Page122 Page122 were recorded. Intraand intergroup comparisons were made using ANOVA, post hoc Bonferroni tests, and Pearson correlation analysis. Results: Points A1 and A2 showed minimal variation from Point A across all groups and had the highest correlation coefficients, indicating strong reliability. Point A3 demonstrated the greatest variability, particularly in proclined incisors, while A4 and A5 were moderately reliable in retroclined cases but inconsistent elsewhere. Conclusion: Point A1 emerged as the most consistent and reliable alternative to Point A, regardless of incisor inclination. Point A2 serves as a viable secondary landmark. A3, A4, and A5 should be used with caution due to positional variability influenced by incisor angulation. Keywords: Cephalometric Analysis Maxillary Alveolar Process, SNA Angle Introduction Cephalometric analysis is an indispensable tool in orthodontic diagnosis, treatment planning, and the evaluation of growth and treatment-related changes. It allows for the quantitative assessment of skeletal, dental, and soft tissue relationships through standardized radiographic landmarks. Among the various skeletal landmarks, Point A (subspinale) plays a pivotal role. It is defined as the most concave point on the anterior contour of the maxillary alveolar process, located between the anterior nasal spine and the crest of the maxillary alveolar ridge. Point A is integral to several cephalometric parameters such as the SNA angle, which denotes maxillary position in relation to the cranial base, and the ANB angle, a fundamental indicator of sagittal skeletal discrepancies between the maxilla and mandible. Additionally, it contributes to Wits appraisal and other skeletal evaluations used to diagnose Class I, II, and III malocclusions.1 Despite its importance, the accurate identification of Point A can often be challenging. One of the key variables that affect its localization is the inclination of the maxillary incisors. In clinical orthodontics, maxillary incisors are frequently subjected to various movements, including proclination, retroclination, or vertical repositioning. Such movements may significantly influence the shape and position of the surrounding alveolar bone, thereby altering the concavity that defines Point A. These changes can result in variations in landmark identification, leading to potential inaccuracies in diagnostic measurements and treatment planning.2 This challenge has prompted researchers and clinicians to explore alternative strategies for more reliable and reproducible localization of Point A, particularly in cases with altered maxillary incisor inclinations. Various geometrically derived methods and anatomical surrogate approaches have been proposed in the literature to address this issue. These alternative methods attempt to identify Point A based on relatively stable skeletal or dental landmarks, thereby reducing the dependency on variable soft tissue or alveolar contours that may be affected by orthodontic treatment.3 However, the comparative validity and reliability of these alternative methods—especially across a range of maxillary incisor inclinations—have not been thoroughly investigated. Variability in cephalometric tracing and landmark identification can compromise the reproducibility of orthodontic assessments, especially in growing patients or cases involving significant dental compensation. Hence, it becomes essential to systematically evaluate these methods under controlled parameters to determine their clinical utility.3 Dr. Mehak, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page123 Page123 Page123 Page123 Page123 Page123 Page123 Page123 Page123 Page123 Page123 Page123 Page123 Page123 Page123 Page123 Page123 Page123 Page123 The present study aims to conduct a comparative cephalometric evaluation of five alternative methods for estimating Point A under varying maxillary incisor inclinations. By analyzing a sample of lateral cephalograms with different incisor angulations, the study will assess the consistency, accuracy, and reliability of each method in relation to a gold standard reference. This investigation seeks to identify the method least influenced by incisor inclination, thereby offering clinicians a more dependable approach for cephalometric analysis in both diagnosis and treatment monitoring. Ultimately, the findings of this study could contribute to improved diagnostic precision, better treatment planning, and enhanced inter-examiner reproducibility in cephalometric assessments, especially in cases where dental-alveolar changes are expected or have already occurred. Material and Methodology The study was conducted on 120 lateral cephalograms of patients reporting to the Department of Orthodontics and Dentofacial Orthopaedics at Guru Nanak Dev Dental College and Research Institute, Sunam. Lateral Cephalogram (figure 1) was traced using 3H lead pencil on acetate tracing paper under X ray viewer box and then sample was divided into 3 groups based on the maxillary incisor inclination (U1-PP angle). Figure 1: Cephalometric Landmarks  Group A – 40 participants with normally inclined incisors.  Group B – 40 participants with proclined incisors.  Group C – 40 participants with retroclined incisors. Point A as suggested by Downs and five alternative points for estimation of point A suggested in the literature was marked and evaluated in all the three groups. The deepest midline point on the premaxilla between the anterior nasal spine and prosthion taken as point A (Downs).4 A point plotted 3 mm labial to a point between the upper third and lower two third of the long axis of the root of the maxillary central incisor taken as point A1.1 (figure 2) Point formed by the intersection of a line parallel to the palatal plane, 7mm below, and the anterior contour of maxilla as the replacement for point A, taken as point A2.5 (figure 3) Point at the intersection of projection of point prosthion on a line parallel to the palatal plane, 7 mm below the palatal plane taken as point A3.3 (figure 4) Point which is located on the anterior surface of the image of the labial lamella at the region of the apex of the maxillary incisors taken as point A4.6 (figure 5). Point which is 2 mm ahead of the root apex of maxillary incisors taken as point A5. (figure 6) Figure 2: Point A1 Dr. Mehak, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page124 Page124 Page124 Page124 Page124 Page124 Page124 Page124 Page124 Page124 Page124 Page124 Page124 Page124 Page124 Page124 Page124 Page124 Page124 Figure 3: Point A2 Figure 4: Point A3 Figure 5: Point A4 Figure 6: Point A5 Various angular and linear parameters were evaluated to check the reliability of five alternative methods for estimation of point A. 1. Angular measurements –  SNA, SNA1, SNA2, SNA3, SNA4, SNA5.  U1-NA, U1-NA1, U1-NA2, U1-NA3, U1-NA4, U1NA5.  N-A-Pog, N-A1-Pog, N-A2-Pog, N-A3-Pog, N-A4Pog, N-A5-Pog. 2. Linear measurements – (figure 7)  U1-NA, U1-NA1, U1-NA2, U1-NA3, U1-NA4, U1NA5.  NA-P, NA1-P, NA2-P, NA3-P, NA4-P, NA5-P. Figure 7: Lateral cephalogram tracing showing various linear parameters (NA-P, U1-NA) Results Mean Values of Various Angular And Linear Cephalometric Parameters for Group A, Group B, and Group C (GRAPH 1, 2 and 3) The linear and angular cephalometric parameters were evaluated across the 3 groups. The results were presented as mean and standard deviation of the entire sample among each group. Comparison of All the Angular And Linear Cephalometric Parameters Using One-Way Anova For Group A, B and C (Table 1, 2 And 3) Dr. Mehak, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page125 Page125 Page125 Page125 Page125 Page125 Page125 Page125 Page125 Page125 Page125 Page125 Page125 Page125 Page125 Page125 Page125 Page125 Page125 One-way ANOVA was used to compare the mean values of angular and linear cephalometric parameters. The interpretation disclosed highly statistically significant differences between groups for all angular and linear parameters in Groups A and B. In Group C, all linear variables showed statistically significant differences amongst groups, whereas the angular parameters did not, with the exception of N-A-Pog which showed a significant difference between groups. Table 1: Comparison of All The Angular And Linear Cephalometric Parameters Using One-Way Anova Group A – Normally Inclined Maxillary Incisors Parameter Type Cephalometric Parameter Sum of Squares df Mean Square F p value Angular Parameter (Degree) SNA Between Groups 967.338 5 193.468 13.322 ** Within Groups 3398.125 234 14.522 Total 4365.463 239 U1-NA Between Groups 885.671 5 177.134 5.302 ** Within Groups 7818.125 234 33.411 Total 8703.796 239 N-A-Pog Between Groups 4667.450 5 933.490 24.771 ** Within Groups 8818.400 234 37.685 Total 13485.850 239 Linear Parameter (mm) NA-P Between Groups 921.600 5 184.320 14.780 ** Within Groups 2918.250 234 12.471 Total 3839.850 239 U1-NA Between Groups 1727.971 5 345.594 24.389 ** Within Groups 3315.825 234 14.170 Total 5043.796 239 p≤0.001 highly significant (**) Table 2: Comparison of All the Angular and Linear Cephalometric Parameters Using One-Way Anova Group B - Proclined Maxillary Incisors Parameter Type Cephalometric Parameter Sum of Squares df Mean Square F p value SNA Between Groups 1346.683 5 269.337 15.541 ** Within Groups 4055.300 234 17.356 Total 5401.983 239 U1-NA Between Groups 1431.633 5 286.327 5.197 ** Within Groups 12891.550 234 55.092 Total 14323.183 239 Dr. Mehak, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page126 Page126 Page126 Page126 Page126 Page126 Page126 Page126 Page126 Page126 Page126 Page126 Page126 Page126 Page126 Page126 Page126 Page126 Page126 Angular Parameter (Degree) N-A-Pog Between Groups 6868.971 5 1373.794 21.139 ** Within Groups 15207.025 234 64.987 Total 22075.996 239 Linear Parameter (mm) NA-P Between Groups 1322.238 5 264.448 21.193 ** Within Groups 2919.925 234 12.478 Total 4242.163 239 U1-NA Between Groups 2187.321 5 437.464 70.019 ** Within Groups 1461.975 234 6.248 Total 3649.296 239 p≤0.001 highly significant (**) Table 3: Comparison of All The Angular And Linear Cephalometric Parameters Using One-Way Anova Group C - Retroclined Maxillary Incisors Parameter Type Cephalometric Parameter Sum of Squares df Mean Square F p value Angular Parameter (Degree) SNA Between Groups 230.383 5 46.077 2.256 NS Within Groups 4779.600 234 20.426 Total 5009.983 239 U1-NA Between Groups 154.021 5 30.804 0.731 NS Within Groups 9866.775 234 42.166 Total 10020.796 239 N-A-Pog Between Groups 1400.883 5 280.177 3.751 ** Within Groups 17479.100 234 74.697 Total 18879.983 239 Linear Parameter (mm) NA-P Between Groups 224.600 5 44.920 2.498 * Within Groups 4207.250 234 17.980 Total 4431.850 239 U1-NA Between Groups 482.433 5 96.487 6.957 ** Within Groups 3245.300 234 13.869 Total 3727.733 239 p≤0.001 highly significant (**), p≤0.05 significant (*), p≥0.05 non-significant (NS) Intragroup Comparison Of Various Angular And Linear Parameters Using Post Hoc Test For Group A, B and C (Table 4, 5 And 6) Post hoc (Bonferroni) test was used to determine the specific parameters that deferred from each other. Table 4: Intragroup Comparison of Various Angular and Linear Cephalometric Parameters Using Post Hoc (Bonferroni) Test Dr. Mehak, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page127 Page127 Page127 Page127 Page127 Page127 Page127 Page127 Page127 Page127 Page127 Page127 Page127 Page127 Page127 Page127 Page127 Page127 Page127 Group A – Normally Inclined Maxillary Incisors Angular Parameters (Degree) A. SNA Parameter Mean Difference p-value SNA SNA1 -0.425 NS SNA2 -0.850 NS SNA3 -3.850 ** SNA4 2.125 NS SNA5 2.025 NS SNA1 SNA 0.425 NS SNA2 -0.425 NS SNA3 -3.425 ** SNA4 2.550 * SNA5 2.450 NS SNA2 SNA 0.850 NS SNA1 0.425 NS SNA3 -3.000 * SNA4 2.975 * SNA5 2.875 * SNA3 SNA 3.850 ** SNA1 3.425 ** SNA2 3.000 * SNA4 5.975 ** SNA5 5.875 ** SNA4 SNA -2.125 NS SNA1 -2.550 * SNA2 -2.975 * SNA3 -5.975 ** SNA5 -0.100 NS SNA5 SNA -2.025 NS SNA1 -2.450 NS SNA2 -2.875 * SNA3 -5.875 ** SNA4 0.100 NS p≤0.001 highly significant (**), p≤0.05 significant (*), p≥0.05 non-significant (NS) Dr. Mehak, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page128 Page128 Page128 Page128 Page128 Page128 Page128 Page128 Page128 Page128 Page128 Page128 Page128 Page128 Page128 Page128 Page128 Page128 Page128 B. U1-NA p≤0.001 highly significant (**), p≥0.05 non-significant (NS) Parameter Mean Difference p-value U1-NA U1-NA1 0.175 NS U1-NA2 0.700 NS U1-NA3 3.175 NS U1-NA4 -2.425 NS U1-NA5 -2.400 NS U1-NA1 U1-NA -0.175 NS U1-NA2 0.525 NS U1-NA3 3.000 NS U1-NA4 -2.600 NS U1-NA5 -2.575 NS U1-NA2 U1-NA -0.700 NS U1-NA1 -0.525 NS U1-NA3 2.475 NS U1-NA4 -3.125 NS U1-NA5 -3.100 NS U1-NA3 U1-NA -3.175 NS U1-NA1 -3.000 NS U1-NA2 -2.475 NS U1-NA4 -5.600 ** U1-NA5 -5.575 ** U1-NA4 U1-NA 2.425 NS U1-NA1 2.600 NS U1-NA2 3.125 NS U1-NA3 5.600 ** U1-NA5 0.025 NS U1-NA5 U1-NA 2.400 NS U1-NA1 2.575 NS U1-NA2 3.100 NS U1-NA3 5.575 ** U1-NA4 -0.025 NS Dr. Mehak, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page129 Page129 Page129 Page129 Page129 Page129 Page129 Page129 Page129 Page129 Page129 Page129 Page129 Page129 Page129 Page129 Page129 Page129 Page129 C. N-A-Pog Parameter Mean Difference p-value N-A-Pog N-A1-Pog -1.200 NS N-A2-Pog -2.050 NS N-A3-Pog -7.875 ** N-A4-Pog 5.050 * N-A5-Pog 4.875 * N-A1-Pog N-A-Pog 1.200 NS N-A2-Pog -0.850 NS N-A3-Pog -6.675 ** N-A4-Pog 6.250 ** N-A5-Pog 6.075 ** N-A2-Pog N-A-Pog 2.050 NS N-A1-Pog 0.850 NS N-A3-Pog -5.825 ** N-A4-Pog 7.100 ** N-A5-Pog 6.925 ** N-A3-Pog N-A-Pog 7.875 ** N-A1-Pog 6.675 ** N-A2-Pog 5.825 ** N-A4-Pog 12.925 ** N-A5-Pog 12.750 ** N-A4-Pog N-A-Pog -5.050 * N-A1-Pog -6.250 ** N-A2-Pog -7.100 ** N-A3-Pog -12.925 ** N-A5-Pog -0.175 NS N-A5-Pog N-A-Pog -4.875 * N-A1-Pog -6.075 ** N-A2-Pog -6.925 ** N-A3-Pog -12.750 ** N-A4-Pog 0.175 NS p≤0.001 highly significant (**), p≤0.05 significant (*), p≥0.05 non-significant (NS) Dr. Mehak, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page136 Page136 Page136 Page136 Page136 Page136 Page136 Page136 Page136 Page136 Page136 Page136 Page136 Page136 Page136 Page136 Page136 Page136 Page136 E. U1-NA Parameter Mean Difference p-value U1-NA U1-NA1 1.000 NS U1-NA2 0.850 NS U1-NA3 5.625 ** U1-NA4 -3.200 ** U1-NA5 -3.350 ** U1-NA1 U1-NA -1.000 NS U1-NA2 -0.150 NS U1-NA3 4.625 ** U1-NA4 -4.200 ** U1-NA5 -4.350 ** U1-NA2 U1-NA -0.850 NS U1-NA1 0.150 NS U1-NA3 4.775 ** U1-NA4 -4.050 ** U1-NA5 -4.200 ** U1-NA3 U1-NA -5.625 ** U1-NA1 -4.625 ** U1-NA2 -4.775 ** U1-NA4 -8.825 ** U1-NA5 -8.975 ** U1-NA4 U1-NA 3.200 ** U1-NA1 4.200 ** U1-NA2 4.050 ** U1-NA3 8.825 ** U1-NA5 -0.150 NS U1-NA5 U1-NA 3.350 ** U1-NA1 4.350 ** U1-NA2 4.200 ** U1-NA3 8.975 ** U1-NA4 0.150 NS p≤0.001 highly significant (**), p≥0.05 non-significant (NS) Dr. Mehak, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page137 Page137 Page137 Page137 Page137 Page137 Page137 Page137 Page137 Page137 Page137 Page137 Page137 Page137 Page137 Page137 Page137 Page137 Page137 Table 6: Intragroup Comparison of Various Angular and Linear Cephalometric Parameters Using Post Hoc (Bonferroni) Test Group C – Retroclined Maxillary Incisors, Angular Parameters (Degree) A. SNA Parameter Mean Difference p-value SNA SNA1 -0.375 NS SNA2 -0.350 NS SNA3 -1.800 NS SNA4 1.175 NS SNA5 0.950 NS SNA1 SNA 0.375 NS SNA2 0.025 NS SNA3 -1.425 NS SNA4 1.550 NS SNA5 1.325 NS SNA2 SNA 0.350 NS SNA1 -0.025 NS SNA3 -1.450 NS SNA4 1.525 NS SNA5 1.300 NS SNA3 SNA 1.800 NS SNA1 1.425 NS SNA2 1.450 NS SNA4 2.975 NS SNA5 2.750 NS SNA4 SNA -1.175 NS SNA1 -1.550 NS SNA2 -1.525 NS SNA3 -2.975 NS SNA5 -0.225 NS SNA5 SNA -0.950 NS SNA1 -1.325 NS SNA2 -1.300 NS SNA3 -2.750 NS SNA4 0.225 NS Dr. Mehak, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page138 Page138 Page138 Page138 Page138 Page138 Page138 Page138 Page138 Page138 Page138 Page138 Page138 Page138 Page138 Page138 Page138 Page138 Page138 p≥0.05 non-significant (NS) B. U1-NA Parameter Mean Difference p-value U1-NA U1-NA1 0.350 NS U1-NA2 0.250 NS U1-NA3 1.450 NS U1-NA4 -0.900 NS U1-NA5 -0.875 NS U1-NA1 U1-NA -0.350 NS U1-NA2 -0.100 NS U1-NA3 1.100 NS U1-NA4 -1.250 NS U1-NA5 -1.225 NS U1-NA2 U1-NA -0.250 NS U1-NA1 0.100 NS U1-NA3 1.200 NS U1-NA4 -1.150 NS U1-NA5 -1.125 NS U1-NA3 U1-NA -1.450 NS U1-NA1 -1.100 NS U1-NA2 -1.200 NS U1-NA4 -2.350 NS U1-NA5 -2.325 NS U1-NA4 U1-NA 0.900 NS U1-NA1 1.250 NS U1-NA2 1.150 NS U1-NA3 2.350 NS U1-NA5 0.025 NS U1-NA5 U1-NA 0.875 NS U1-NA1 1.225 NS U1-NA2 1.125 NS U1-NA3 2.325 NS U1-NA4 -0.025 NS p≥0.05 non-significant (NS) Dr. Mehak, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page139 Page139 Page139 Page139 Page139 Page139 Page139 Page139 Page139 Page139 Page139 Page139 Page139 Page139 Page139 Page139 Page139 Page139 Page139 C. N-A-Pog Parameter Mean Difference p-value N-A-Pog N-A1-Pog -1.025 NS N-A2-Pog -1.000 NS N-A3-Pog -3.600 NS N-A4-Pog 3.375 NS N-A5-Pog 2.950 NS N-A1-Pog N-A-Pog 1.025 NS N-A2-Pog 0.025 NS N-A3-Pog -2.575 NS N-A4-Pog 4.400 NS N-A5-Pog 3.975 NS N-A2-Pog N-A-Pog 1.000 NS N-A1-Pog -0.025 NS N-A3-Pog -2.600 NS N-A4-Pog 4.375 NS N-A5-Pog 3.950 NS N-A3-Pog N-A-Pog 3.600 NS N-A1-Pog 2.575 NS N-A2-Pog 2.600 NS N-A4-Pog 6.975 * N-A5-Pog 6.550 * N-A4-Pog N-A-Pog -3.375 NS N-A1-Pog -4.400 NS N-A2-Pog -4.375 NS N-A3-Pog -6.975 * N-A5-Pog -0.425 NS N-A5-Pog N-A-Pog -2.950 NS N-A1-Pog -3.975 NS N-A2-Pog -3.950 NS N-A3-Pog -6.550 * N-A4-Pog 0.425 NS Dr. Mehak, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page140 Page140 Page140 Page140 Page140 Page140 Page140 Page140 Page140 Page140 Page140 Page140 Page140 Page140 Page140 Page140 Page140 Page140 Page140 Linear Parameters (mm) NA-P Parameter Mean Difference p-value NA-P NA1-P -0.425 NS NA2-P -0.375 NS NA3-P -1.425 NS NA4-P 1.475 NS NA5-P 1.050 NS NA1-P NA-P 0.425 NS NA2-P 0.050 NS NA3-P -1.000 NS NA4-P 1.900 NS NA5-P 1.475 NS NA2-P NA-P 0.375 NS NA1-P -0.050 NS NA3-P -1.050 NS NA4-P 1.850 NS NA5-P 1.425 NS NA3-P NA-P 1.425 NS NA1-P 1.000 NS NA2-P 1.050 NS NA4-P 2.900 * NA5-P 2.475 NS NA4-P NA-P -1.475 NS NA1-P -1.900 NS NA2-P -1.850 NS NA3-P -2.900 * NA5-P -0.425 NS NA5-P NA-P -1.050 NS NA1-P -1.475 NS NA2-P -1.425 NS NA3-P -2.475 NS NA4-P 0.425 NS p≤0.05 significant (*), p≥0.05 non-significant (NS) Dr. Mehak, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page141 Page141 Page141 Page141 Page141 Page141 Page141 Page141 Page141 Page141 Page141 Page141 Page141 Page141 Page141 Page141 Page141 Page141 Page141 D. U1-NA Parameter Mean Difference p-value U1-NA U1-NA1 0.450 NS U1-NA2 0.325 NS U1-NA3 1.850 NS U1-NA4 -2.175 NS U1-NA5 -2.000 NS U1-NA1 U1-NA -0.450 NS U1-NA2 -0.125 NS U1-NA3 1.400 NS U1-NA4 -2.625 * U1-NA5 -2.450 NS U1-NA2 U1-NA -0.325 NS U1-NA1 0.125 NS U1-NA3 1.525 NS U1-NA4 -2.500 * U1-NA5 -2.325 NS U1-NA3 U1-NA -1.850 NS U1-NA1 -1.400 NS U1-NA2 -1.525 NS U1-NA4 -4.025 ** U1-NA5 -3.850 ** U1-NA4 U1-NA 2.175 NS U1-NA1 2.625 * U1-NA2 2.500 * U1-NA3 4.025 ** U1-NA5 0.175 NS U1-NA5 U1-NA 2.000 NS U1-NA1 2.450 NS U1-NA2 2.325 NS U1-NA3 3.850 ** U1-NA4 -0.175 NS p≤0.001 highly significant (**), p≤0.05 significant (*), p≥0.05 non-significant (NS) Group A – Normally Inclined Maxillary Incisors Angular Parameters SNA1 differed significantly from SNA4. SNA2 revealed statistically significant difference from SNA4 and SNA5. Dr. Mehak, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page142 Page142 Page142 Page142 Page142 Page142 Page142 Page142 Page142 Page142 Page142 Page142 Page142 Page142 Page142 Page142 Page142 Page142 Page142 Statistically significant variations were noticed amongst SNA3 and all other SNA measurements (SNA, SNA1, SNA2, SNA4, SNA5). U1-NA3 showed significant differences, specifically from U1-NA4 and U1-NA5. All other angular measurements were statistically similar. NA-Pog, N-A1-Pog, N-A2-Pog showed statistically significant difference from N-A4-Pog and N-A5-Pog. NA3-Pog significantly differed from all other N-A-Pog variants. Linear Parameters Post hoc analysis revealed that NA-P showed statistically significant differences from NA4-P. NA1-P and NA2-P showed notable difference from NA4-P and NA5-P. NA3-P was statistically significantly different from all other variants (NA-P, NA1-P, NA2-P, NA4-P, and NA5P). U1-NA, U1-NA1, U1-NA2 exhibited a statistically highly significant variation among U1-NA4, U1-NA5. U1-NA3 was statistically significantly different from all other variants (U1-NA, U1-NA1, U1-NA2, U1-NA4, and U1-NA5). Group B – Proclined Maxillary Incisors Angular Parameters Analysis revealed that SNA1 and SNA2 was statistically different from SNA5. SNA3 was statistically distinct from all other SNA variants (SNA, SNA1, SNA2, SNA4, SNA5). U1-NA3 displayed a statistically highly significant variation compared to U1-NA4 and U1-NA5. N-A1-Pog and N-A2-Pog showed statistically significant differences with N-A4-Pog and N-A5-Pog. N-A3-Pog differed significantly from all other variants (N-A-Pog, N-A1-Pog, N-A2-Pog, N-A4-Pog, N-A5-Pog). Linear Parameters Both NA1-P and NA2-P differed statistically from NA4-P and NA5-P. NA3-P showed statistically significant differences from all other variants (NA-P, NA1-P, NA2P, NA4-P, and NA5-P). U1-NA, U1-NA1 and U1-NA2 showed highly statistically significant differences when compared to U1-NA4 and U1-NA5. Additionally, U1NA3 exhibited a statistically highly significant difference among all other variations (U1-NA, U1-NA1, U1-NA2, U1-NA4, and U1-NA5). Group C – Retroclined Maxillary Incisors Angular Parameters No statistically significant differences were found between SNA, U1-NA, and their alternative parameters. N-A3-Pog displayed a statistically significant variation from both N-A4-Pog and N-A5-Pog. Linear Parameters NA3-P presented a statistically significant variation from NA4-P. U1-NA1 and U1-NA2 also demonstrated statistically relevant disparities when compared to U1NA4. U1-NA3 exhibited a highly statistically notable contrast with both U1-NA4 and U1-NA5. Correlation Coefficient for Comparison of All Five Alternative Points To Original Parameter For All The Three Groups (Graph 1, 2, 3) The Pearson correlation coefficient revealed a highly significant positive correlation between all alternative angular and linear parameters and the original parameters across all three groups. Graph 1: Correlation Coefficient for Comparison of All Five Alternative Parameters To Original Parameter Group A – Normally Inclined Maxillary Incisors Angular Parameters (Degree) Dr. Mehak, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page143 Page143 Page143 Page143 Page143 Page143 Page143 Page143 Page143 Page143 Page143 Page143 Page143 Page143 Page143 Page143 Page143 Page143 Page143 Linear Parameters (mm) Graph 2: Correlation Coefficient for Comparison Of All Five Alternative Parameters To Original Parameter Group B – Proclined Maxillary Incisors Angular Parameters (Degree) Graph 3: Correlation Coeeficient For Comparison Of All Five Alternative Parameters To Orignial Parameter Group C – Retroclined Maxillary Incisors Angular Parameters (Degree) Linear Parameters (mm) Intergroup Comparison Using One – Way Anova (Table 7) Angular Parameters Statistically significant intergroup differences were observed for SNA–SNA3, SNA–SNA4, and SNA–SNA5. U1–NA differed statistically from all its alternative Dr. Mehak, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page144 Page144 Page144 Page144 Page144 Page144 Page144 Page144 Page144 Page144 Page144 Page144 Page144 Page144 Page144 Page144 Page144 Page144 Page144 parameters. N-A-Pog also showed statistically significant variation across all groups when compared with N-A2Pog, N-A3-Pog, and N-A5-Pog. Table 7: Intergroup Comparison Using OneWay Anova And Independent T-Test Angular Parameters (Degree) Parameter Mean difference p-value Group A Group B Group C Overall A vs B A vs C B vs C SNA -SNA1 0.425 0.725 0.375 NS NS NS NS SNA -SNA2 0.850 0.700 0.350 NS NS * NS SNA-SNA3 3.850 5.000 1.800 ** * ** ** SNA-SNA4 2.125 1.950 1.175 * NS * * SNA-SNA5 2.025 2.175 0.950 ** NS * ** U1-NA-U1-NA1 0.175 0.925 0.350 * * NS NS U1-NA-U1-NA2 0.700 0.800 0.250 * NS * * U1-NA-U1-NA3 3.175 4.825 1.450 ** ** ** ** U1-NA-U1-NA4 2.425 2.350 0.900 ** NS ** ** U1-NA-U1-NA5 2.400 2.450 0.875 ** NS ** ** N-A-Pog-N-A1-Pog 1.200 2.475 1.025 NS NS NS * N-A-Pog-N-A2-Pog 2.050 2.175 1.000 * NS * * N-A-Pog-N-A3-Pog 7.875 10.875 3.600 ** ** ** ** N-A-Pog-N-A4-Pog 5.050 4.750 3.375 NS NS * NS N-A-Pog-N-A5-Pog 4.875 5.050 2.950 * NS * * p≤0.001 highly significant (**), p≤0.05 significant (*), p≥0.05 non-significant (NS) Linear Parameters (mm) Parameter Mean difference p-value Group A Group B Group C Overall A vs B A vs C B vs C NA-P-NA1-P 0.300 0.925 0.425 NS NS NS NS NA-P-NA2-P 0.750 0.875 0.375 NS NS NS * NA-P-NA3-P 3.300 4.700 1.425 ** ** ** ** NA-P-NA4-P 2.475 2.150 1.475 * NS * * NA-P-NA5-P 2.325 2.325 1.050 ** NS * * U1-NA-U1-NA1 0.525 1.000 0.450 NS NS NS NS U1-NA-U1-NA2 0.950 0.850 0.325 NS NS * NS U1-NA-U1-NA3 4.625 5.625 1.850 ** NS ** ** U1-NA-U1-NA4 3.275 3.200 2.175 * NS * * U1-NA-U1-NA5 3.150 3.350 2.000 * NS * * Dr. Mehak, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page145 Page145 Page145 Page145 Page145 Page145 Page145 Page145 Page145 Page145 Page145 Page145 Page145 Page145 Page145 Page145 Page145 Page145 Page145 p≤0.001 highly significant (**), p≤0.05 significant (*), p≥0.05 non-significant (NS) Linear Parameters Statistically significant differences were observed for NA-P compared to NA3-P, NA4-P, and NA5-P. U1–NA also differed significantly from U1–NA3, U1–NA4, and U1–NA5. Intergroup Comparison Using Independent T-Test (Table 7) Angular Parameters SNA2 displayed a statistically significant variation amongst Groups A and C, while SNA3, U1–NA3, and NA3-Pog showed statistically significant differences across all groups. SNA4, SNA5, U1–NA2, U1–NA4, U1–NA5, and N-A2-Pog differed statistically between Group C and the other groups. U1–NA1 and N-A1-Pog exhibited statistically significant variations amongst Groups A and B, and Groups B and C, respectively. N-A4-Pog differed statistically between Groups B and C. Linear Parameters NA3-P showed statistically significant differences across all groups. NA4-P differed statistically between Group C and the others. U1–NA2 displayed statistically significant variations amongst Groups A and C, while U1–NA3, U1– NA4, and U1–NA5 differed statistically between Group C and the others. Discussion In this investigation, the reliability of five alternative landmarks to Point A was assessed across 120 subjects. The primary goal was to determine how consistently these alternative points could be identified, particularly in clinical scenarios where Point A is challenging to locate due to anatomical variation or image quality. To explore the effect of upper incisor inclination on landmark visibility and reproducibility, subjects were categorized into three groups: normally inclined, proclined, and retroclined maxillary incisors. A sample size of 120 was selected based on a power analysis conducted using G*Power 3.1.9.7 software (Heinrich Heine University. Düsseldorf, Germany), ensuring adequate power (95%) and a low probability of type I error (α = 0.05). This sample size was sufficient to detect significant differences among the groups and support robust comparisons based on incisor inclination. Previous studies, such as those by Patel et al. (2014) and Singh & Shivaprakash (2018),7,8 have addressed the difficulty of accurately locating Point A and suggested alternative landmarks. Building on this, the present study evaluates five alternatives (A1–A5) across a wider range of maxillary incisor inclinations. Unlike Singh & Shivaprakash’s two-group approach, this study includes a third group with normally inclined incisors, enhancing clinical relevance. Subjects were stratified into three groups—normally inclined, proclined, and retroclined— to assess the influence of incisor angulation on the reliability of alternative landmarks. Standardized cephalograms using the same X-ray unit minimized magnification errors, ensuring consistent measurements. Comparative Evaluation of Angular and Linear Parameters in Group A (Normally Inclined Maxillary Incisors) In individuals with normally inclined maxillary incisors, significant variation (p ≤ 0.001) was observed across all six reference points (A, A1–A5) in both angular and linear parameters. Among angular measurements, SNA showed the most variation. Points A1 and A2 exhibited minimal deviation from Point A, confirming their reliability—findings consistent with Patel et al. (2014) and Poudel et al. (2021).7,9 A3 showed higher SNA values due to its anterior position, echoing Singh and Shivaprakash (2018),8 who deemed it the least reliable.