Comparison of Bolton analysis and tooth size measurements obtained using conventional and three-dimensional orthodontic models

ABSTRACT

Objectives: The aim of this study was to compare the accuracy, reproducibility, efficacy and effectiveness of measurements obtained using digital models with those obtained using plaster models. Materials and Methods: A total of 20 digital models were produced by the Ortho Three-dimensional Models (O3DM) Laboratory and their software (O3DM version 2) was used to obtain measurements. Identical plaster models were used to obtain measurements of teeth with a vernier caliper. The maximum mesiodistal width of each study model, from first molar to first molar, was measured. All measurements were repeated at least 1 month later by the same operator for both digital and manual methods. The data were analyzed using Cronbach α, Wilcoxon signed rank test and the McNemar test. Results: Cronbach α value of the data at T1 and T2 for 6 anterior and 12 overall teeth measured using the two methods was very close to the ideal value of 1, indicating high intra-observer reliability. The Wilcoxon signed rank test showed statistically significant differences between the two methods (p = 0.000, P < 0.001). The measurements obtained using the digital models were lower than those obtained using the plaster models. No statistically significant differences were found between the two methods for anterior Bolton discrepancies (p = 0.375) or overall Bolton discrepancies (p = 0.00). Paired comparisons of repeated measurements for Bolton ratios showed no statistically significant differences for anterior or overall Bolton discrepancies (p = 0.688 and P = 0.375, respectively). Conclusions: Use of O3DM software is an acceptable alternative to the traditional vernier caliper method in orthodontic practice.

Key words:

Bolton ratio - digital model - tooth size - vernier caliper

• REFERENCES

• 1 Bolton WA. Disharmony in tooth size and its relation to the analysis and treatment of malocclusion. Angle Orthod 1958; 28: 113-30
• 2 Shellhart WC, Lange DW, Kluemper GT, Hicks EP, Kaplan AL. Reliability of the Bolton tooth-size analysis when applied to crowded dentitions. Angle Orthod 1995; 65: 327-34
• 3 Schirmer UR, Wiltshire WA. Manual and computer-aided space analysis: A comparative study. Am J Orthod Dentofacial Orthop 1997; 112: 676-80
• 4 Champagne M. Reliability of measurements from photocopies of study models. J Clin Orthod 1992; 26: 648-50
• 5 Bhatia SN, Harrison VE. Operational performance of the travelling microscope in the measurement of dental casts. Br J Orthod 1987; 14: 147-53
• 6 Mårtensson B, Rydén H. The holodent system, a new technique for measurement and storage of dental casts. Am J Orthod Dentofacial Orthop 1992; 102: 113-9
• 7 Halazonetis DJ. Acquisition of 3-dimensional shapes from images. Am J Orthod Dentofacial Orthop 2001; 119: 556-60
• 8 Ramsay DS, Soma M, Sarason IG. Enhancing patient adherence: The role of technology and its application to orthodontics. In: McNamara Jr JA, Trotman CA. editors. Creating the Compliant Patient. Craniofacial Growth Series. Vol. 33. Ann Arbor: Center for Human Growth and Development, University of Michigan; 1997: p. 141-65
• 9 Mok KH, Cooke MS. Space analysis: A comparison between sonic digitization (Digigraph workstation) and the digital caliper. Eur J Orthod 1998; 20: 653-61
• 10 Ayoub AF, Wray D, Moos KF, Jin J, Niblett TB, Urquhart C. et al. A three-dimensional imaging system for archiving dental study casts: A preliminary report. Int J Adult Orthodon Orthognath Surg 1997; 12: 79-84
• 11 Bell A, Ayoub AF, Siebert P. Assessment of the accuracy of a three-dimensional imaging system for archiving dental study models. J Orthod 2003; 30: 219-23
• 12 Tomassetti JJ, Taloumis LJ, Denny JM, Fischer Jr JR. A comparison of 3 computerized Bolton tooth-size analyses with a commonly used method. Angle Orthod 2001; 71: 351-7
• 13 Quimby ML, Vig KW, Rashid RG, Firestone AR. The accuracy and reliability of measurements made on computer-based digital models. Angle Orthod 2004; 74: 298-303
• 14 Santoro M, Galkin S, Teredesai M, Nicolay OF, Cangialosi TJ. Comparison of measurements made on digital and plaster models. Am J Orthod Dentofacial Orthop 2003; 124: 101-5
• 15 Zilberman O, Huggare JA, Parikakis KA. Evaluation of the validity of tooth size and arch width measurements using conventional and three-dimensional virtual orthodontic models. Angle Orthod 2003; 73: 301-6
• 16 Proffit WR. Contemporary Orthodontics. 3 rd ed. St. Louis, MO: Mosby 2000; P. 169-70
• 17 Stevens DR, Flores-Mir C, Nebbe B, Raboud DW, Heo G, Major PW. Validity, reliability, and reproducibility of plaster vs digital study models: Comparison of peer assessment rating and Bolton analysis and their constituent measurements. Am J Orthod Dentofacial Orthop 2006; 129: 794-803
• 18 Mullen SR, Martin CA, Ngan P, Gladwin M. Accuracy of space analysis with emodels and plaster models. Am J Orthod Dentofacial Orthop 2007; 132: 346-52