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Assembly and clinical use of XCP-ORA: a three-function dental X-ray film positioning device for taking anterior and posterior periapical and bitewing intraoral radiographs.

Abstract:

This article describes the assembly and clinical use of a newer type of XCP dental X-ray film positioning device, called the XCP-ORA. The previous version of the XCP consists of three separate devices for taking anterior, posterior, and bitewing radiographs. The XCP-ORA dental X-ray film holder combines all three of these dental X-ray functions into one device, in contrast to the previous generation of XCP holders. The large paralleling ring of the device contains three color-coded square-shaped holes that attach to a metal rod. This single metal rod with two right angle bends contains two sets of corresponding color-coded prongs that attach the anterior, posterior and bitewing X-ray film holders. One set of prongs consists of two red prongs that correspond to the insertion points of the bitewing X-ray film holder. The other set of prongs consists of one prong that is yellow colored, and another prong that is blue colored. Both of these prongs fit into the insertion holes of either the yellow (posterior) or the blue (anterior) film holders. The multi-function XCP-ORA device reduces the total number of XCP parts that are needed to take intraoral dental radiographs. Fewer parts make the device less confusing to assemble and reduce the number of steps that are needed to prepare the XCP-ORA parts for autoclaving.

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The XCP-ORA is a type of dental X-ray film positioning device. XCP-ORA stands for "eXtension Cone Paralleling-One Ring and Arm" This acronym refers to the device's capability to enable an assistant to parallel the plane of the difficult-to-see intra-orally located dental X-ray film with the cross-section of the X-ray beam as the beam emerges from the extension (or collimating) tube that extends from the X-ray machine head. It also refers to the ability to use this one device to perform all three functions of taking anterior periapical, posterior periapical and bitewing radiographs. This article describes the clinical techniques of assembling the XCP-ORA device and of positioning it intra-orally for taking dental radiographs. The reader should, however, consult other sources for a complete overview of how to produce a full mouth series of radiographs or how to take oral and maxillo-facial radiographs in general. (1-3)

The XCP-ORA device contains a film holder that provides a stiff backing plane for the film, allowing intra-oral placement of the film so as to overcome intra-oral muscular forces that might normally dislodge a film placed intra-orally by itself without a backing support. A metal rod connects the film holder to a large circular guiding or paralleling ring, the plane of which is parallel to the film-holding plane of the film holder. The assistant aligns the plane of the X-ray tube opening parallel with the plane of the extra-orally located paralleling ring. By doing so, the assistant parallels the plane of an imaginary cross-section of the X-ray beam (cut perpendicularly to the beam or at a right angle to it) with the plane of the intra-orally located film.

The three-function XCP-ORA dental X-ray positioning device consists of five different parts, three parts of which together make a specific assemblage for taking anterior, posterior or bitewing radiographs, respectively. (Figure 1, p.39, bottom left).

One part is a small film holder piece. There are three types of these film holders, which are color-coded. The two periapical radiographic film holders are colored yellow for posterior and blue to distinguish anterior. The film holder for bitewing radiographic imaging is colored red. The film holder piece consists of two fused planes. One plane holds the dental X-ray film (which fits into slots on that plane) while another plane is a platform that the patient occludes into to hold the X-ray film holder and film in position. The occluding platform contains two insertion holes for the prongs of a metal connecting rod.

A second part is the metal connecting rod, which connects the film holder piece with the large circular paralleling ring. The metal rod lies flat on a two-dimensional plane and has two sets of two prongs on it. One set of prongs is color-coded red; the insertion holes of the red bitewing film holder connect into both of these prongs when taking bitewing radiographs.

Another set of prongs consists of one prong that is yellow colored, and another prong that is blue colored. These two prongs fit into the insertion holes of either the yellow (posterior) or the blue (anterior) film holders. Whether the yellow or the blue film holder is used, both insertion holes of that piece will connect into the prongs.

When a film holder is connected to one set of the prongs, the other set of prongs is unused and is left open. The metal connecting rod is designed so that, when the XCP-ORA is fully assembled for a particular type of imaging (anterior, posterior or bitewing), and the XCP-ORA device is positioned intra-orally, the unused set of prongs will be located extra-orally and out of the way of the patient's bite.

A third part is a large circular paralleling ring that contains three square-shaped insertion holes in it. The holes are color-coded red, blue and yellow, for bitewing, anterior and posterior films, respectively. The non-prong end of the metal rod (which is also square-shaped in cross section) inserts into the color--coded hole that corresponds to the type of radiographic image to be taken to connect the film holder with the paralleling ring.

Assembling the three-function XCP-ORA device

The author suggests that, in general, the assistant begins assembling the three-function XCP device by first orienting the film holder part of the device in three-dimensional space, given what type of imaging (anterior, posterior or bitewing) is to be taken (Figure 2, bottom right). Once the film holder is correctly oriented in space, it is more systematic and less confusing to correctly add the metal rod to the film holder. The circular paralleling ring should be the last part added to the XCP-ORA assemblage, after the metal rod and the film holder have been attached.

[FIGURE 1 OMITTED]

Assembling the XCP-ORA device for taking bitewing radiographs

The bitewing X-ray film holder consists of two planes, a film-holding plane and a bite plane. The film-holding plane is fused at its midline to the bite plane. The film-holding plane contains two film-holding slots. The X-ray film packet is oriented horizontally and is placed into these slots so that the white side of the film packet faces the bite plane of the film holder. The bite plane of the film holder is placed between the maxillary and mandibular teeth being imaged so that the patient can occlude on it. The bitewing film holder would be oriented in the mouth so that the film-holding plane is located between the tongue and the lingual aspect of the teeth being imaged. (Figure 3, pg. 40, bottom left)

After attaching the metal rod to the properly oriented bitewing X-ray film holder, the large round paralleling ring is attached to the metal rod by inserting the non-prong end of the metal rod through the red bitewing insertion slot on the paralleling ring. The paralleling ring is correctly attached to the metal rod when the assistant can see the white side of the X-ray film packet within the ring and also when the film appears centered within the ring when the assistant looks through the ring. That is, the top and bottom sides of the film are both equidistant, respectively; from the top and bottom aspects of the paralleling ring, and the left and right sides of the film are both equidistant, respectively; from the left and right aspects of the paralleling ring.

[FIGURE 2 OMITTED]

There is only one correct assemblage of the bitewing X-ray film holder, and this assemblage enables imaging of the posterior teeth of both the left and the right sides of a patient requiring bitewing radiographs.

Some assistants may assemble the bitewing XCP in an "inverted" way; by reversing the orientation of the bitewing film holder so that the bite plane is towards the medial aspect of the mouth and the film-holding plane and its film-holding slots face the teeth being imaged. Here, the film is placed so that the white part of the film faces away from the film-holding plane and away from the bite plane. The assemblage is placed intra-orally so that the bite plane pushes the tongue out of the way: This way of assembling the bitewing XCP is technically incorrect, although it may produce acceptable bitewing films. (Figure 4, page 40, bottom right)

Assembling the XCP-ORA device for taking anterior periapical radiographs

The anterior X-ray film holder consists of two planes, a film-holding plane and a bite plane. They are both of the same width and are fused to each other at a right angle. The bite plane contains at its end the two insertion holes for the two prongs (one yellow and one blue) on the metal rod. The film-holding plane contains a slot at the bottom in which the dental X-ray film is placed. The white, exposure, side of the film packet faces away from the film-holding plane of the anterior X-ray film holder, and faces towards the bite plane of the film holder.

When taking maxillary anterior periapical images, the anterior X-ray film holder is oriented in the mouth so that the film-holding plane of the anterior film holder is superior to the bite plane of the anterior film holder. The superior aspect of the film-holding plane is close to or barely touching the superior aspect of the palate. The bite plane is oriented so that the patient's anterior teeth occlude as close to the end of the bite plane as is practical, and the two insertion holes at the end of the bite plane are located at or just anterior to the mouth opening.

When taking mandibular anterior periapical images the anterior X-ray film holder is oriented in the mouth so that the film-holding plane of the anterior film holder is inferior to the bite plane of the anterior film holder. The inferior end of the film-holding plane protrudes (gently) into the floor of the patient's mouth. The patient's anterior teeth occlude into the end of the bite plane.

The set of two prongs, one of which is yellow while the other is blue, on the metal rod inserts into the insertion holes on the anterior (blue) X-ray film holder. The metal rod is oriented so that the two unused red bitewing prongs on the rod are located lateral to the patient's mouth opening. The other non-prong end of the metal rod protrudes anteriorly, straight out in front of the lateral aspect of the patient's mouth opening. (Figure 5, pg. 42, bottom left)

[FIGURE 3 OMITTED]

The large paralleling ring is then attached to the metal rod, by sliding the non-prong end of the metal rod through the blue insertion slot on the paralleling ring. The paralleling ring is correctly oriented when the assistant can see the white side of the dental X-ray film packet when looking directly through the ring, and the film appears centered within the ring. That is, the top and bottom sides of the dental X-ray film appear equidistant from the top and bottom sides, respectively; of the paralleling ring, and the left and right sides of the film appear equidistant from the left and right sides, respectively; of the paralleling ring.

There is only one correct assemblage of the anterior X-ray film holder, and this assemblage enables imaging of both the maxillary and mandibular anterior dentition.

Assembling the XCP-ORA device for taking posterior periapical radiographs

The posterior X-ray film holder consists of a film-holding plane and a bite plane, with the film-holding plane wider than the bite plane. The planes are fused to each other to form a right angle. The end of the bite plane contains two insertion holes for the two corresponding prongs (one yellow and one blue) on the metal rod. The film-holding plane has a slot at the bottom in which the dental X-ray film is placed. The white, exposure, side of the film packet faces away from the film-holding plane of the posterior X-ray film holder.

[FIGURE 4 OMITTED]

The large paralleling ring is then attached to the metal rod, by sliding the non-prong end of the metal rod through the insertion slot located within the yellow posterior X-ray protrusion on the paralleling ring. The paralleling ring is correctly oriented when the assistant sees the plain white side of the film packet when looking directly through the ring, and the dental X-ray film appears centered when looking directly through the ring. That is, the top and bottom sides of the dental X-ray film appear equidistant from the top and bottom sides, respectively; of the paralleling ring, and the left and right sides of the film appear equidistant from the left and right sides, respectively; of the paralleling ring.

The film-holding plane is superior to the bite plane when the X-ray film holder is oriented in the mouth to take maxillary posterior images of the teeth. The superior edge of the film-holding plane is close to or touching the midline of the palate. The film-holding plane is positioned as parallel as possible with the lingual aspect of the posterior teeth being imaged. The posterior X-ray film holder bite plane protrudes towards the lateral aspect of the patient's mouth, so that the posterior teeth being imaged occlude into the edge of the bite plane.

When taking images of mandibular posterior teeth, the posterior X-ray film holder is oriented in the mouth so that the film-holding plane is inferior to the bite plane. The inferior edge of the film-holding plane is gently pressed into the floor of the mouth so that it is positioned between the tongue and the lingual aspect of the posterior teeth being imaged. The film-holding plane is positioned as parallel as possible with the lingual aspect of the posterior teeth being imaged. The posterior X-ray film holder bite plane protrudes towards the lateral aspect of the patient's mouth.

The two prongs, one of which is yellow and the other blue in color, on the metal rod insert into the insertion holes on the posterior X-ray film holder. When the posterior XCP-ORA assemblage is placed intra-orally, the metal rod is oriented so that the two unused red bitewing prongs on the metal rod are positioned anterior to the patient's mouth opening. The other end of the metal rod (non-prong end) protrudes laterally to the patient's mouth opening. (Figure 6, bottom right)

There are two possible ways of assembling the posterior XCP-ORA device. The posterior XCP-ORA assemblage that enables imaging of one quadrant of posterior teeth also enables imaging of the opposite diagonal quadrant of posterior teeth. For example, the assemblage that enables imaging of the maxillary right posterior dentition also enables imaging of the mandibular left posterior dentition. Likewise, the assemblage that enables imaging of the maxillary left posterior dentition also enables imaging of the mandibular right posterior dentition.

[FIGURE 5 OMITTED]

Avoiding sensitive intra-oral structures while positioning the XCP-ORA device

In general, prior to placing the XCP-ORA device, the assistant should briefly look inside the patient's mouth to identify intra-oral structures that a dental X-ray film packet may impinge upon. These include mandibular tori (if present), the floor of the mouth, palatal tori (if present), the palatal midline, the lingual boundaries of the mandibular gingiva and the palatal boundaries of the maxillary dentition.

After identifying the locations of these intra-oral structures in the patient's mouth, the assistant should also observe the sizes or dimensions of these structures. For example, a dental arch that has a narrow or acute angle of curvature towards the anterior, or that features large mandibular anterior tori that protrude lingually, may feature a small horizontal distance between the opposing lingual sides of the arch towards the anterior.

As a result, the comers of an adult sized film may aggressively push into the lingual aspects of the arch, unless the film is placed more posteriorly so that its comers do not impinge as such. Otherwise, an assistant may use a pediatric-sized film instead of an adult sized film in this area.

[FIGURE 6 OMITTED]

In general, the assistant should continuously observe the locations of the comers and edges of the dental X-ray film packet while placing an XCP device to ensure that the comers are not aggressively pushing into sensitive intra-oral structures.

When taking mandibular X-rays, the comers and edges of film used should be between the tongue and the lingual aspect of the gingiva during placement. The vertical depth of the lingual sulcus, and the amount of flexibility or "give" of the muscles in the floor of the mouth, affect how deeply a film may be placed in the floor of the mouth. The inferior edge of the film should be contacting that aspect of the floor of the mouth where there is maximum muscular flexibility or displacement in a downward direction. An assistant should use his or her best judgment to determine where this area of maximum flexibility is located in the floor of the mouth.

If the edges and corners of an adult sized film push too aggressively into intra-oral structures, so that the film cannot be placed posteriorly enough to obtain a complete image of the third molars, a pediatric sized film may be small enough to enable such imaging. The smallness of a pediatric sized film may enable an assistant to place a posterior XCP assemblage posteriorly, and then subsequently to rotate the assemblage in a posterior-medial direction, so that the imaginary axis connecting the paralleling ring and the film passes through the third molars.

Conclusion

The three function XCP-ORA dental X-ray positioning device combines anterior, posterior and bitewing dental X-ray positioning functions in one device. This may simplify the process of manually taking dental radiographic films and the process of cleaning and sterilizing the XCP device, since fewer parts are needed to take the three forms of X-rays. The XCP-ORA device also comes with film holders that are shaped to accept the various sizes of digital X-ray sensors. There may be less need for use of manual intraoral film positioning devices to take a full mouth series of radiographs in the future because digital panoramic or three-dimensional cone beam scans can be used to computer-generate a full mouth series of images. However, there will likely remain a need to take single dental radiographs manually using X-ray positioning devices.

Acknowledgements

The author would like to thank Ghena Mamoun and Anna-Marie Triano, RDA, for assistance in taking photographs for this article.

References

(1.) Hating, Joen Iannucci, and Lind, Laura Jansen. Dental Radiography: Principles and Techniques. 3d ed. Philadelphia, Saunders, 2005.

(2.) Whaites, E. Essentials of dental radiography and radiology. Edinburgh: Churchill Livingstone, 3rd edition, 2002.

(3.) White S, Pharaoh M. eds. Oral radiology: principles and interpretation. 5th ed. St Louis, Mo: Mosby, 2004.

John Mamoun, DMD, is a 2003 graduate of the University of Medicine and Dentistry of New Jersey. He completed a one-year Advanced Education in General Dentistry residency at the Eastman Dental Center, a division of the University of Rochester Medical School in Rochester, N.Y., and later earned Fellowship from the Academy of General Dentistry. He is currently in private practice in Manalapan, N.J. Dr. Mamoun has published several articles in peer-reviewed dental journals and serves as a manuscript reviewer for General Dentistry, the peer-reviewed journal of the Academy of General Dentistry. He is currently interested in analyzing how the use of high-magnification loupes or microscopes in clinical practice can lead to improved diagnoses and treatments of dental problems.
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Title Annotation:Clinical
Author:Mamoun, John S.
Publication:The Dental Assistant
Date:May 1, 2011
Words:3263
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