口腔顎顏面放射線學會
專科醫師繼續教育課程
Buccal Object Rule
從X光片辨識物體位置
2011/11/05
陳玉昆副教授: 高雄醫學大學 口腔病理科
07-3121101~2755
yukkwa@kmu.edu.tw
大
綱
Introduction
Understand buccal object rule
Assessment of the impacted
maxillary canine tooth position
Summaries
References:
1. White & Pharoah: Oral radiology: principle & interpretation, 5th edition,
Chapter 5, p. 91-93
2. Eric Whaites: Essentials of dental radiography & radiology, 3rd edition,
p.7, 8, 113, 279-283
Introduction
* In 1909, Clark [1] reported a radiographic procedure for
the localization of impacted teeth.
* The Buccal Object Rule is a method for determining the
relative location of objects hidden in the oral region.
* The rule is: When two different radiographs are made of a
pair of objects, the image of the buccal object moves,
relative to the image of the lingual object, in the same
direction that the X-ray beam is directed.
* The initial concepts of the procedure were reported in 1952
& 1953 [2, 3] & since that time the procedure has been
developed to its present state of refinement & usefulness.
[1] CLARK C A. A method of ascertaining the relative position of unerupted teeth by means of film
radiographs. Royal Society of Medicine Transactions 3:87-90, 1909-1910.
[2] RICHARDS AG. Roentgenographic localization of the mandibular canal. Journal of Oral Surgery
10:325-329, 1952.
[3] RICHARDS AG. The Buccal object rule. Journal of the Tennessee State Dental Association 33:263268, 1953.
Understand buccal object rule
Buccal object rule
Lingual
Tube shift technique
Mesial shift
Clake’s rule (1910)
同方向移動
Zygomatic
process
X-ray beam
Direct
orientation
Buccal
Zygomatic process
往mesial方向移
(與X-ray beam相反
方向移動)
Mesial shift 相反方向移動
Ref. 1
X-ray beam
Distal shift
Assessment of the impacted
maxillary canine tooth position
1. Parallax in the horizontal plane
2. Parallax in the vertical plane
3. A vertex occlusal
4. A true PA and lateral skull views
(two views at right angles)
*Impacted maxillary canine teeth occur in about 2% of the population.
1. Parallax in the horizontal plane
Principle of parallax: The apparent displacement of
an object due to different positions of the observer
Object moves in different direction
Left
Same
Ref. 2
Right
Front
Lingual Opposite
(遠方)
Buccal
(近方)
SLOB
1. Parallax in the horizontal plane
Position 2distal shift
11
Position 1centrally
oriented
Same
Lingual
(遠方-palatal side)
Ref. 2
12
1. Parallax in the horizontal plane
12
12
11
22
21
21
22
Choice
Same
Ref. 2
Lingual
(遠方)
Opposite
Buccal
(近方)
1. Parallax in the horizontal plane
Choice
Ref. 2
Same
Lingual
(遠方)
Apex
Opposite
Buccal
(近方)
Crown
2. Parallax in the vertical plane
Unerupted
mesiodens
Upper occlusal
Panorex
Lingual
Crown portion Same
(遠方-palatal side)
Apex portion Opposite
Buccal
(近方-labial side)
Ref. 2
SLOB
3. A vertex occlusal
Not recommended
due to high radiation
dose
Vertex occlusal
Ref. 2
4. A true PA and lateral skull views
(two views at right angles)
Similar images
PA view
PA view
Mass of head in a different
position & different shape
Similar images
Ref. 2
Radiodense object
Lateral view
Summaries
http://www.unc.edu/~jbl/
Summaries
http://www.unc.edu/~jbl/
Summaries
http://www.unc.edu/~jbl/
Thank you very much
for your kind
attention