Guest Editorial

The collimation and film speed mystery in dental radiology: what doesit take for a dentist to change?Theodore P, Croir

It has long been known that coUimalion of the x-raybeam used in intraoral radiographie procedures great-ly decreases the dose of radiation received by the pa-tient. The only portion of the x-ray beam that is ofany use is that which hits the x-ray film. Extraneous,radiation absorbed by surrounding body tissues hasno diagnostic value and should be eltminated as muchas possible.

It is also well documented that E-type dental x-rayfilm, introduced by Eastman Kodak Company in 1981as Ektaspeed, requires about one half the time ex-posure required by Kodak's slower D-type (Uhra-Speed) film to produce an equivalent diagnostic im-age.

However, decades after Precision Instruments (Ma-sei Orthodontics) were introduced, and almost 10years after Ektaspeed ftlm was first tnarketed, it isdisturbing and embarrassing that only a minority ofdentists use the faster film, and few dentists in theUnited States use Precision Instruments or collimationof any kind. The failure of dentists to flock to the useof colhmation techniques is bewildering because, be-sides elimination of much radiation, collimators makeintraoral radiologie procedures quicker, easier, andmuch more consistent. Few retakes are required, andtime and costs are saved by an efficient atid reliabletechnique. In addition, the quality of the radiographieimage obtained using collimation instruments is un-surpassed. Because radiographs serve as medicolegaldocumentation of patient care, and excellent qualityfilms are necessary for proper diagnosis and treatment

' Private Practice, Peciiatric Dentistry, Doylestown, Pennsylvania;Clinical Associate Professor, Department of Pédiatrie Detitistry.University of Pennsylvania, School of Dental Medicine; AdjutictClinical Professor, Departtncnt of Pédiatrie Dentistry, Universityoí' Tesas Health Science Center at Houston, Dental Branch.

Address all correspondence to Dr. T, P, CroM, East Street and NorthMain Street, Doylestown, Pennsylvania 18901-3S97,

planning, I would think that all dentists would strivefor the highest quality radiographs with the least ir-radiation of patients possible.

The only understandable reason for a modern den-tist not to use collimation or Ektaspeed ftlm is igtio-rance of the existence of these two methods of radia-tion reduction. This essay was written to rectify suchignorance, A proper intraoral radiographie techniqueis demonstrated pictorially, and a bibliography is pro-vided for dentists to use for study of this subject soimportant to patients.

Figures 1-5 illustrate the procedure of recording in-traoral radiographs. Use of Precision Tn.struments forperiapical images and a "clip-on" Ring Collimator(Rinn Corp) for bite-wing radiographs, representativeinstrument use, patient posifions, and resultant radio-graphs are shown, ! routinely use the Rinn clip-oncollimator plate for bite-wing radiographs because itis easier to use than the Precision bite-wing system.

It is estimated that with use of body and neck leadapron shielding, Ektaspeed ftlm, and stainless steelcollirnator plates with expo.sure windows, head andneck x-radiation expositre is reduced generally by 60%to 90% (Reiskin A: Personal communication, Feb-ruary 1990), The exact percentage of reduction de-pends on which anatomic site is considered.

Criticism that Ektaspeed tllm results in inferiorquahty images and that the Precision heam-guiding/field-si¿e I i mi ting/ft im-align ment instruments are un-wieldy, uncomfortable, and therefore unusable arecompletely unjustifted when the fiim is exposed andprocessed correctly, and the instruments are usedthoughtfully.

It is long past time to change dental radiographietechniques. Patients and parents of young patients arecounting on dentists to use all available methods tominimize radiation exposure during diagnostic radio-graphic procedures. To possess the knowledge of thebenefits of x-ray beam collimation and E-type x-rayfilm and not share those benefits with patients is un-conscionable.

Ojintefáence International Volume 21, lumber 6/1990 429

Guest Editorial

Fig 1 This 5-year-old displays a Precision field-size l¡m¡t-ing/beam-guiding/film-aligning collimating device and Ek-taspeed intraoral x-ray film.

Fig 2a The "Elcan" PrecJsicn Instrument is ideal for max-illary and mandibular occlusal radiographs in young chil-dren.

Fig 2b This 5-year-old demonstrates proper technique torrecording a maxillary occlusal radiograph.

Fig 2c A proper technique tor recording a mandibular oc-clusal radiograph.

Fig2d Representative ocdusal radiographs obtained using the Elcan Precision Instrument.

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Guest Editorial

Fig 3a The Rinn clip-on ring collirnator used tor bite-wingradiograptis is shown from the front view.

Fig 3b The Rinn clip-on collimating plate is shown tromthe back view.

Fig 3c A proper bite-wing technique is shown using theRinn eollimator and "XCP" aiigning instrument.

Fig 3d (rigbt) Representative bite-wing radiographs ob-tained with the Rinn instruments are shown.

Fig 4a The Precision Instrument for vertical orientation ofNo, 2 x-ray film is used for [arge periapicai radiographs.

Fig 4b This 11-year-old boy demonstrates a proper tech-nique for recording a maxiilary central incisor periapicalradiograph.

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Fig 4c A proper technique for recording a mandibular an-terior periapical view.

Fig4d A proper technique for recording a periapical ra-diograph of the maxillary canine region.

Fig 4e Representative periapical radiographs obtained byuse of Precision Instruments for verticai positioning of No,2 x-ray film.

Fig 5a Precision Instrumerits for positioning of No, 0 andNo, 2 x-ray film in me posterior regions.

Fig 5b This child demonstrates a proper technique for re-cording a maxiliary posterior periapical radiograph.

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Fig 5c A proper tectirtique for a mandibular posterior peri-apical radiograph.

Fig5d (right) Representative maxillary and mandibularmolar radiographs obtained by use of the Precision Instru-ment as shown in Figs 5b and 5c.

Fig5e A proper technique for recording a mandibularposterior periapical radiograph in an 11-year-old.

Fig 5f Representative radiograph resulting from the tech-nique shown in Fig 5e.

Fig 5g This young adult demonstrates a proper techniquefor recording a periapical radiograph of the third molarregion.

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Fig 5h Represetitative third molar regional views usingthe Precision Instrument and No, 2 x-ray film.

Bibliography

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6, Greer D: Determination and analysis of absorbed doses result-ing from various intraoral radiograpliic techniques. Oral ,SwgOrat Med Oral Palhol 1972:34:146-162,

7, American Dental Association Council on Dental Materials andDevices: Precision x-ray device classified as acceptable. J AmDem A.-:soc 1972;85:372,

8, Alcox RW, Jameson WR: Patient exposures Irom intraoral ra-diographie examination, J Am Dem As.mc 1974:SB: 568-579.

9, Valachovic RW, Lurie AG: Risk-benefit considerations in pe-dodontic radiology. Pediair Dem 1980;2:128-i46.

10. Silha RE: The new Kodak Ektaspeed dental x-ray lilm. DentRadiogr Piioiogr 198i;54:32-35,

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12. American Dental Association Council on ÛL-atal Materials, In-strutnents. and Equipment: Bioloeical effects of radiation fromdental radiography, / Am Dent A.i.'^oc 1982;1O5:275-2K1,

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14. Girsch WJ, Matesor SR, McKee MN: An evaluation of KodikEktaspeed periapical film for use in endodontics, J Eiiduil1983:9:282-288.

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Í6. Grondahl K, Grondahi H-G, Olving A: A comparison of KodakEktaspeed and tjltra-speed films for the detection of periodontalbone lesions, Dentoma.xillofiii: Radioi 1983; 12:43-46,

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2t). Horton PS, Sippy FH, Kohout FJ, et al: A clinical comparisonor speed group D and E dental x-ray films. Oral Surg Orai MaiOral Pathol 1984:58:104-108.

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iVlanufacturers

Masel Ortbodiintici, Inc2701 Bartram RoadBristol. Pennsylvania 19007Rinn Corporation1212 Abbot DriveElgin, Illinois 6U123Eastman Kodak Company, Inc343 State StreetRochesler, New York 14650

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