Document Detail

Analysis of intra-arch and interarch measurements from digital models with 2 impression materials and a modeling process based on cone-beam computed tomography.
MedLine Citation:
PMID:  20362900     Owner:  NLM     Status:  MEDLINE    
INTRODUCTION: Study models are an essential part of an orthodontic record. Digital models are now available. One option for generating a digital model is cone-beam computed tomography (CBCT) scanning of orthodontic impressions and bite registrations. However, the accuracy of digital measurements from models generated by this method has yet to be thoroughly evaluated. METHODS: A plastic typodont was modified with reference points for standardized intra-arch and interarch measurements, and 16 sets of maxillary and mandibular vinylpolysiloxane and alginate impressions were made. A copper wax-bite registration was made with the typodont in maximum intercuspal position to accompany each set of impressions. The impressions were shipped to OrthoProofUSA (Albuquerque, NM), where digital orthodontic models were generated via CBCT. Intra-arch and interarch measurements were made directly on the typodont with electronic digital calipers and on the digital models by using OrthoProofUSA's proprietary DigiModel software. RESULTS: Percentage differences from the typodont of all intra-arch measurements in the alginate and vinylpolysiloxane groups were low, from 0.1% to 0.7%. Statistical analysis of the intra-arch percentage differences from the typodont of the alginate and vinylpolysiloxane groups had a statistically significant difference between the groups only for maxillary intermolar width. However, because of the small percentage differences, this was not considered clinically significant for orthodontic measurements. Percentage differences from the typodont of all interarch measurements in the alginate and vinylpolysiloxane groups were much higher, from 3.3% to 10.7%. Statistical analysis of the interarch percentage differences from the typodont of the alginate and vinylpolysiloxane groups showed statistically significant differences between the groups in both the maxillary right canine to mandibular right canine (alginate with a lower percentage difference than vinylpolysiloxane) and the maxillary left second molar to mandibular left second molar (alginate with a greater percentage difference than vinylpolysiloxane) segments. This difference, ranging from 0.24 to 0.72 mm, is clinically significant. CONCLUSIONS: In this study, digital orthodontic models from CBCT scans of alginate and vinylpolysiloxane impressions provided a dimensionally accurate representation of intra-arch relationships for orthodontic evaluation. However, the use of copper wax-bite registrations in this CBCT-based process did not result in an accurate digital representation of interarch relationships.
Aaron J White; Drew W Fallis; Kraig S Vandewalle
Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics     Volume:  137     ISSN:  1097-6752     ISO Abbreviation:  Am J Orthod Dentofacial Orthop     Publication Date:  2010 Apr 
Date Detail:
Created Date:  2010-04-05     Completed Date:  2010-05-04     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8610224     Medline TA:  Am J Orthod Dentofacial Orthop     Country:  United States    
Other Details:
Languages:  eng     Pagination:  456.e1-9; discussion 456-7     Citation Subset:  D; IM    
Copyright Information:
Copyright (c) 2010 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.
Tri-Service Orthodontic Residency Program, Wilford Hall Medical Center, Lackland Air Force Base, San Antonio, TX 78236, USA.
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MeSH Terms
Alginates / chemistry
Bicuspid / anatomy & histology
Cephalometry / methods,  statistics & numerical data*
Cone-Beam Computed Tomography / methods*
Copper / chemistry
Cuspid / anatomy & histology
Dental Arch / anatomy & histology*
Dental Impression Materials / chemistry*
Dental Models / standards*
Image Processing, Computer-Assisted / methods,  statistics & numerical data*
Incisor / anatomy & histology
Jaw Relation Record / instrumentation
Mandible / anatomy & histology
Maxilla / anatomy & histology
Molar / anatomy & histology
Pilot Projects
Polyvinyls / chemistry
Siloxanes / chemistry
Reg. No./Substance:
0/Alginates; 0/Dental Impression Materials; 0/Polyvinyls; 0/Siloxanes; 0/vinyl polysiloxane; 7440-50-8/Copper

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