Korean J Orthod.  2013 Apr;43(2):54-61. 10.4041/kjod.2013.43.2.54.

Use of Reference Ear Plug to improve accuracy of lateral cephalograms generated from cone-beam computed tomography scans

• Hwang HS
• Lee KM
• Uhm GS
• Cho JH
• McNamara J

• KMID: 1975142
• DOI: http://doi.org/10.4041/kjod.2013.43.2.54

Abstract

OBJECTIVE
The purpose of this study was to evaluate the effectiveness of the use of Reference Ear Plug (REP) during cone-beam computed tomography (CBCT) scan for the generation of lateral cephalograms from CBCT scan data.
METHODS
Two CBCT scans were obtained from 33 adults. One CBCT scan was acquired using conventional methods, and the other scan was acquired with the use of REP. Virtual lateral cephalograms created from each CBCT image were traced and compared with tracings of the real cephalograms obtained from the same subject.
RESULTS
CBCT scan with REP resulted in a smaller discrepancy between real and virtual cephalograms. In comparing the real and virtual cephalograms, no measurements significantly differed from real cephalogram values in case of CBCT scan with REP, whereas many measurements significantly differed in the case of CBCT scan without REP.
CONCLUSION
Measurements from CBCT-generated cephalograms are more similar to those from real cephalograms when REP are used during CBCT scan. Thus, the use of REP is suggested during CBCT scan to generate accurate virtual cephalograms from CBCT scan data.

Keyword

Cone-beam computed tomography; Virtual cephalogram; Accuracy; Reference Ear Plug

MeSH Terms

Adult
Cone-Beam Computed Tomography
Ear
Humans

Figure

• 

  Figure 1 Reference Ear Plug used in this study. A, A titanium ball marker 1.0 mm in diameter is located in the center of each ear plug; B, a subject with ear plugs positioned in the earholes. By simulating ear rods in a conventional cephalometric apparatus, two ball markers are represented on a volume-rendering image.

• 

  Figure 2 This window shows the process for generating a virtual lateral cephalogram from a 3D volume-rendering image using a cone-beam computed tomography scan with Reference Ear Plug (REP). The virtual central ray is geometrized using the right and left titanium ball markers of the REP (top left and right). Using the function of the program, a virtual lateral cephalogram is created (bottom right).

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