Comparative study of soft tissue parameters reliability by digital and manual tracing method: A cephalometric study

 Corresponding author: Nikhith Navin Kumar Copyright © 2025 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution Liscense 4.0. Comparative study of soft tissue parameters reliability by digital and manual tracing method: A cephalometric study Nikhith Navin Kumar 1, *, Anil Kumar 2, Pratham Shetty 3, Thomas Abraham 1 and Simran Naik 1 1 Postgraduate, Department of Orthodontics and Dentofacial Orthopedics, AJ Institute of Dental Sciences, Mangalore, Karnataka, India. 2 Reader, Department of Orthodontics and Dentofacial Orthopedics, AJ Institute of Dental Sciences, Mangalore, Karnataka, India. 3 Assistant Professor, Department of Orthodontics and Dentofacial Orthopedics, AJ Institute Of Dental Sciences, Mangalore, Karnataka, India. World Journal of Biology Pharmacy and Health Sciences, 2025, 21(03), 145-160 Publication history: Received on 05 January 2025; revised on 24 February 2025; accepted on 27 February 2025 Article DOI: https://doi.org/10.30574/wjbphs.2025.21.3.0189 Abstract Aim: To compare and evaluate soft tissue linear and angular measurements reliability between Digital and Manual Tracing method Objectives: The objective of the study is to conclude that digital and manual tracing method for soft tissue measurements are reliable and comparable to each other Materials & methods: Lateral Cephalograms of 35 patients who reported for Orthodontic Treatment irrespective of the type of malocclusion were taken. A total of 24 measurements were taken with 17 Linear Soft Tissue Measurements and 7 Angular Soft Tissue Measurements respectively. The digital images of each cephalogram was directly imported to Nemoceph Software for digital tracing whereas for manual tracing compatible printed images were used. Results: Soft Tissue Chin Thickness, Lower Lip Thickness, A’- B’, Sn’-Pog’, Upper Lip Length, Upper Lip Protrusion, Upper Lip Anterior - Lower Lip Anterior showed statistically significant difference between the two techniques among linear measurements but were clinically acceptable (difference between the digital and manual technique were less than 2 units ie 1 unit = 1mm for linear measurement and 1 degree for angular measurements). Throat Length also showed statistically significant difference between the two techniques for linear measurement but was not clinically acceptable as it exceeded 2mm difference. Amongst the Angular measurement only Z-Angle Upper Lip showed statistically significant difference between the two techniques but was clinically acceptable. Conclusion: Digital measurements were found to be reliable and comparable to manual tracing method for all soft tissue linear and angular measurements except Throat Length. Keywords: Nemoceph; Soft Tissue Parameters; Cephalogram; Digital Tracing; Manual Tracing; Reliability 1. Introduction One of the most important tool in orthodontics is cephalometric analysis as it plays a key role in diagnosis, treatment planning, growth prediction, treatment results evaluation. Hand tracing has been the go to method for orthodontists for a while but now there is a shift from conventional method of hand tracing to the digital tracing as we evolve with World Journal of Biology Pharmacy and Health Sciences, 2025, 21(03), 145-160 146 technology.[1] We know that manual tracing method is a tedious process even though its been used since long time as it is time consuming, fatigue of the operator, incorrect identification of landmarks and therefore leading to errors in measurements.[2-5] Now as we evolve with technology the patient’s concerns have also evolved ie they are more aware and concerned about the esthetic point of view so due to which soft tissue analysis is gaining popularity among orthodontists as it also plays a key role in treatment planning and diagnosis.[6] There could be a possibility at times when hard tissue cephalometric criteria does not necessarily ensure overlying soft tissue will drape in a harmonious manner therefore not resulting in a pleasing profile so therefore highlighting the importance of soft tissues.[7] It is reported that very few studies have been evaluated on soft tissue landmarks due to the uncertainty in identifying it.[8] It is also reported that digitally acquired cephalometric imaging has numerous advantages ie elimination of chemical processing and dark room, reduced radiation exposure, improved landmark identification through image enhancement techniques, faster cephalometric data acquisition, efficient storage and archiving.[6,9,10] Some of the cephalometric software programs used are Quick ceph [10], Dolphin [6,11], Vista-dent [12], Nemoceph [13]. 1.1. Need for the study To compare and evaluate soft tissue parameters both digitally and manually in order to check the reliability of digital tracing of soft tissue in comparison to manual tracing to provide the best possible treatment for the patient. 1.2. Null hypothesis Digital tracing method is not reliable and comparable to manual tracing method for soft tissue linear and angular measurements 1.3. Alternative hypothesis Digital tracing method is reliable and comparable to manual tracing method for soft tissue linear and angular measurements. 1.4. Aim To compare and evaluate soft tissue linear and angular measurements reliability between Digital and Manual Tracing method Objectives • To Evaluate Linear and Angular Soft tissue measurements for digital tracing method • To Evaluate Linear and Angular Soft tissue measurements for manual tracing method • To Compare Linear and Angular Soft tissue measurements between digital and manual tracing method 2. Material and methods Ethical clearance was obtained for the study from the Institutional Ethics Committee, A.J. Institute of Dental Sciences. Pre-treatment Lateral Cephalograms of 35 patients (both hard and soft copies) who reported for Orthodontic treatment from Department of Orthodontics and Dentofacial Orthopedics, AJ Institute of Dental Sciences, Mangalore were taken irrespective of the type of malocclusion and gender. The inclusion criteria for this study were as follows • All Radiographs should be taken from the same machine with same magnification • Lateral Cephalograms should be obtained in natural head position • Only Soft Tissue Linear and Angular Parameters were measured taken from Arnett, COGS Soft Tissue Analysis and Tweed-Merrifield Analysis The exclusion criteria were as follows • Patients with Trauma, Craniofacial deformity, syndromes Following are the materials used for performing the study • Pre Treatment Lateral Cephalogram both Hard and Soft Copy World Journal of Biology Pharmacy and Health Sciences, 2025, 21(03), 145-160 147 • Acetate Tracing Sheet • Sharp 3H 0.5mm Drawing Pencil • Vernier Caliper • Protractor • Nemoceph Cephalometric Software For Manual Tracing, Soft tissue landmarks were traced on a acetate tracing sheet using sharp 3H 0.5mm drawing pencil using transilluminated light in a dark room and is made sure that no light radiations were present around the radiograph so that all landmarks were identified as accurately as possible. First the 3 registration crosses are marked ie 2 of them in the cranium and 1 near the cervical vertebrae region on the hard copies [14]. Using smooth continuous pressure on the pencil, tracing is done without stopping ie continuous freehand and also erasures are avoided as much as possible. Average between the left and right outlines were taken when there was lack of superimposition between them to mark the landmarks. Once all the outlines were drawn and landmarks were identified, the Linear and Angular measurements were done using parameters only from Arnett, COGS Soft Tissue Analysis and Tweed Merrifield Analysis [15,16,17]. Angular measurements were taken using protractor and for linear measurements a digital vernier caliper was used to give an accurate measurement. The same lateral cephalograms were stored as soft copies and then transferred to Nemoceph Software to perform digital tracing. The image was saved in the software with patient’s details for future references. First the image was calibrated by identifying 2 points which are 10 mm apart. Then, the software guides us to identify all the individual cephalometric landmarks so as to avoid confusions and to be as accurate as possible with the help of mouse. After identifying all the landmarks readjustment was done to correct all the outlines and points so as to increase the accuracy of the measurements. The software calculated automatically all the measurements for the parameters which we used for the study. Whichever parameters were to be measured it was checked whether its present in any of the 3 analysis (Arnett, COGS Soft tissue, Tweed Merrifield) so therefore that particular analysis was used to find out the measurements of the required parameter. Once all the parameters were measured digitally for angular and linear measurements the values were noted down so as to compare it with manual tracing measurements. Statistical Analysis was performed for all the data obtained. 2.1. Measurements taken were as follows 2.1.1. Linear soft tissue measurement • Soft Tissue Chin Thickness (Pog-Pog’) • Upper Lip Thickness • Lower Lip Thickness • Menton - Menton’ • Ga’ – Pog’ • Ga’ – Pt. A’ • Pt. A’ – Pt. B’ • Inter-labial Gap • Throat Length • Pt. B’ – Pog’ • Na’ – Me’ • Sn’ – Pog’ • Upper Lip Length (Sn - ULI) • Lower Lip Length (LLS - Me’) • Upper Lip Anterior to Lower Lip Anterior (ULA - LLA) • Upper Lip Protrusion • Lower Lip Protrusion 2.1.2. Angular soft tissue measurements • Soft Tissue Facial Angle (G’- Sn - Pog’) • Upper Lip Angle • Lower Face Throat Angle (Sn - Gn) & (C - Gn) • Nasolabial Angle (C – Sn - ULA) • Z - Angle (Upper Lip) • Z - Angle (Lower Lip) World Journal of Biology Pharmacy and Health Sciences, 2025, 21(03), 145-160 148 • Facial Convexity Angle (G-Sn) & (Sn – Pog’) A Total of 24 parameters were taken with 17 Linear Measurements and 7 Angular Measurements The measurements between Manual and Digital tracing were considered to be clinically acceptable if the mean measurement difference between them were less than 2 units (1 unit = 1 mm for linear measurements and 1 degree for angular measurements). [9,18] 2.2. Statistical analysis Intra examiner error was measured by randomly repeating 10 selected radiographs. The measurement difference between the two sets of reading was statistically non-significant. The measurement between digital and manual tracing was subjected to paired t-tests for statistical analysis with p<0.05 deemed statistically significant FACIAL ANGLE FACIAL CONVEXITY ANGLE World Journal of Biology Pharmacy and Health Sciences, 2025, 21(03), 145-160 149 NASOLABIAL ANGLE UPPER LIP ANGLE Z-ANGLE UL World Journal of Biology Pharmacy and Health Sciences, 2025, 21(03), 145-160 150 Z-ANGLE LL LOWER FACE THROAT ANGLE UPPER LIP PROTRUSION World Journal of Biology Pharmacy and Health Sciences, 2025, 21(03), 145-160 151 LOWER LIP PROTRUSION UPPER LIP THICKNESS INTERLABIAL GAP World Journal of Biology Pharmacy and Health Sciences, 2025, 21(03), 145-160 152 SN’-POG’ B’-A’ G’-POG’ World Journal of Biology Pharmacy and Health Sciences, 2025, 21(03), 145-160 153 G’-A’ POG’-B’ N’-ME’ World Journal of Biology Pharmacy and Health Sciences, 2025, 21(03), 145-160 160 [10] Johnson DR, English J, Gallerano R. Comparison of hand traced and computerized cephalograms: landmark identification, measurement, and superimposition accuracy. Am J Orthod Dentofac Orthop. 2008; 133:56-64. [11] Sayinsu K, Isok F, Trakyali G, Arun T. An evaluation of errors in cephalometric measurements on scanned cephalometric images and conventional tracings. Eur J Orthod. 2007;29:105-108 [12] Celik E, Oszoy OP, Memikoglu TUT. Comparison of cephalometric measurements with digital versus conventional cephalometric analysis. Eur J Orthod. 2009,31 (3):241-246 [13] Tikku T, Khanna R, Maurya RP, Srivastava K, Bhushan R. Comparative evaluation of cephalometric measurements of monitor-dsiplayed images by Nemoceph Software and its Hard Copy by Manual Tracing. J Oral Biol Craniofac Res 2014 Jan-Apr;4(1):35-41 [14] Jacobson, A Radiographic cephalometry: from basics to video imaging. Chicago: Quintessence Publishing Co.;1995.p.336 [15] Arnett GW, Jelic JS, Kim J, Cummings DR, Beress A, Worley CM, Chung B and Bergman R. Soft tissue cephalometric analysis: diagnosis and treatment planning of dentofacial deformity. Am J OrthoDentofacialOrthop 1999; 116:239-53 [16] Burstone C, James R, Legan H, Murphy G, Norton L. Cephalometrics for orthognathic surgery. Journal of Oral Surgery 1978;36:269-77. [17] Vaden JL. Tweed-Merrifield Philosophy [18] Schultze RKW, Dent M, Gloede MB, Doll GM. Landmark identification on direct digital versus film based cephalometric radiographs e A human skull study. Am J Orthod Dentofac Orthop. 2002; 122:635-642. [19] Cooke MS, Wei SH. Cephalometric errors: a comparison between repeat measurements and retaken radiographs. Aust Dent J. 1991;36:38-43 [20] Kublashvili T, Kula K, Craven R, Vadachkoria Z. Reliability of soft tissue cephalometric parameters using conventional and digital cephalometric radiogram. Ann Biomed Res Educ. 2002;2(4):316-322. [21] Yu SH, Nahm DS, Baek SH. Reliability of landmark identification on monitor-displayed lateral cephalometric images. 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