- Email: [email protected]
Evaluation of panoramic dental radiographs taken in private practice
dental radiology Editor: JOHN W. PREECE, D.D.S.
American Academy of Dental Radiology Department of Dental Diagnostic Sciences School of Dentistry, The University of Texas Health Science Center at San Antonio 7703 Floyd Curl Dr. San Antonio, Texas 78284
Evaluation of panoramic dental radiographs taken in private practice Natalia A. Brezden, B.S.,* and Sharon L. Brooks, D.D.S., M.S.,** Ann Arbor, Mich. UNIVERSITY
OF MICHIGAN
Five hundred panoramic radiographs submitted to Delta Dental Plan of Michigan for preauthorization or claim processing were evaluated for frequency of occurrence of 15 categories of technical errors in patient positioning, film processing, and general film handling. Only one radiograph showed no errors. The average radiograph contained 2.2 positioning errors, 1 .O processing errors, and 1.5 miscellaneous errors, for a total of 4.7 errors. Of the 500 radiographs, 467 had positioning errors, 441 had processing errors, and 424 had miscellaneous errors. Diagnostic quality was judged to be adequate in 365 radiographs, inadequate in 91 radiographs and marginal in 44 radiographs. The severity of error was of more importance than the number of errors in the determination of diagnostic adequacy. (ORAL SURG. ORAL MED. ORAL PATHOL. 1987;63:617-21)
H
igh quality radiographs are of vital importance to the practicing dentist as an aid in the proper diagnosis of patients’ dental needs. Artifacts and common technical errors, however, may cause the radiographs to be of marginal or inadequate diagnostic quality, leading to the potential of compromised dental care. Several studies have been published on the frequency of errors on intraoral radiographs taken by dental and dental hygiene students during their training in dental radiography.‘-’ Depending on the radiographic technique used, technical errors occurred on 7.6% to 49.9s4 of the films. Marked improvement in quality was noted as students advanced in their training.’ When Beideman and coworkers* evaluated intraoral radiographs taken in private dental offices and submitted to a third party carrier, they found that only 24.5% showed no technical errors. Even when *Dental student, Class of 1989. Oral Diagnosis and Radiology.
**Professor,
mounting errors were disregarded, only 44.7% were judged to be free of error. In Scandinavian countries, error rates for intraoral radiographs have been reported to be as high as 54% for periapical radiographs9 and 95.4% for bitewing radiographs.‘O In recent years, there has been a large increase in the use of panoramic radiography in dentistry.” Schiff and coworkers’* found that only about 20% of 1,000 randomly selected panoramic radiographs taken in a dental school by students, faculty, or technicians showed no positioning or other errors. A trained technician produced error-free panoramic radiographs 47% of the time. The purpose of this study was to evaluate the quality of panoramic radiographs taken in private dental offices in an effort to determine the need for continuing education in panoramic dental radiography. MATERIALS
AND METHODS
Textbooks on panoramic radiography’3-‘s were consulted in the development of a form to analyze the 617
616
Brezden and Brooks
Oral Surg. May, 1987
Error
Rate in 500 Panoramic from
Private
Radiographs
Practice
120 tn 5 100 i z g iii $
80
:1
20
80 40
0 0
1
9
2345678
Number
of Errors Fig.
quality of each panoramic radiograph screened.The rating factors included the following 15 categories of common errors: 1. A dark shadow above the tongue due to the patient not placing the tongue on the palate. 2. Vertical overlap of teeth due to the patient not biting on a bite block. 3. Artifacts such as lead aprons, dentures, jewelry, hearing aids, and eyeglasses. 4. Vertebral column causing extreme lightness in the anterior region as a result of the superimposed shadow of the spine. 5. Diagnostic information cut off at the lower border of the mandible or at the temporomandibular joint areas. Superimposition of diagnostic information caused by the spine overlapping the condyles or rami. 6. Double exposure. 7. Alternate vertical black and white bands caused by mechanical movements of the x-ray machine. 8. Blurring and distortion of objects (narrowing or widening of images) due to improper placement of the patient’s teeth in the focal trough, either anterior-posteriorly or asymmetrically, or incorrect setting of the profile index meter. 9. The occlusal plane tipped too far down or up, as evidenced by an extreme occlusal “smile” or “frown,” inward or outward tilting of the condyles, and the superimposition of the shadow of the palate on the apices of the maxillary teeth.
10
Per Radiograph
1.
10. Horizontal or vertical movement of patient during exposure, appearing as missing or doubled objects or abrupt shifting of image vertically. 11. A low- or high-density film from improper exposure (kVp) or processing. Fogged film with a uniform gray shade caused by excessive length of processing time, developing solutions that are too warm, excessive storage time or temperature, contaminated and/or depleted chemicals, or improper darkroom lighting. 12. Colored stains caused by accumulated chemicals and foreign material on the rollers of an automated processor. 13. Marks such as static electricity, dust or paper found in the screen, streaking due to processing error, and other marks such as crinkles, fingerprints, scratches, contamination, emulsion tears, water and chemical droplets, and others due to improper handling of the film. 14. Dirty or bent films. 15. Other errors, including films cut in size or cut in half and taped together, labels or paper left in the cassettes,film struck by light, uneven images on the films, etc. A subjective rating of diagnostic quality was also made, based on the significance of the errors and the degree they compromised the diagnostic usefulness of the radiograph. Before beginning the study, the investigators used the rating form developed to evaluate a series of panoramic radiographs several times to ensure con-
Volume 63 Number 5
Evaluation
sistency of judgment of errors. Periodically during the study, the original series was again reviewed and evaluated. Five hundred panoramic radiographs submitted for preauthorization or claim processing to Delta Dental Plan of Michigan (DDPM) in Southfield, Michigan, were reviewed by one of us for technical quality over an 8-week period. To eliminate bias in selection of radiographs, the caseswere evaluated in the order they were received at DDPM on the days chosen for site visits. The data collected were recorded on the rating form and later statistically analyzed by the Michigan Interactive Data Analysis System (MIDAS).
Table
RESULTS
Only one of the 500 panoramic radiographs evaluated had no technical errors present. Of the 499 panoramic radiographs with errors, 276 (55.2%) had 5 or more errors present and 223 (44.6%) had fewer than 5 errors present (Fig. 1). The average radiograph contained 2.2 positioning errors, 1.0 processing error, and 1.5 miscellaneous errors, for a total of 4.7 errors. Positioning mistakes, such as the dark shadow above the tongue, the blurring of anterior teeth, the presence of artifacts, the image of the vertebral column superimposed on the anterior teeth, and the position of the patient’s occlusal plane, accounted for errors on 467 radiographs. In addition, 441 radiographs had processing errors, which included stains and marks, and 424 radiographs had miscellaneous errors, which included diagnostic information being cut off or superimposed, an object missing or portrayed twice, improper density, and other problems in procedures and film handling. The frequency of occurrence of the most common errors is shown in Table I. Of the 500 panoramic radiographs, 414 (82.8%) were of dentulous patients, 8 (1.6%) were of edentulous patients, and 78 (15.6%) were of partially edentulous patients. This uneven distribution was due to selection of radiographs from a source used most often by persons with teeth. No relationship was found between the state of the dentition and the number of errors. In addition, no relationship was found between the type of panoramic machine, split versus continuous image, and the number of errors present. Diagnostic quality was judged to be adequate for 365 radiographs (73.0%), inadequate for 91 radiographs (18.2%), and marginal for 44 radiographs (8.8%). An example of a radiograph judged to be inadequate can be seen in Fig. 2. The average number of total errors per radiograph was 4.5 for
of panoramic dental radiographs
619
I. Frequency of errors in 500 panoramic radiographs Marks on film (fingerprints, scratches, etc.) Vertebral column superimposed on anterior teeth Shadow of airway above tongue Blurry anterior teeth Information cut off on edges of film Occlusal plane too flat Other miscellaneous errors Vertical bands from mechanical movement of x-ray machine Widened anterior teeth Density too low Radiopaque artifacts (earrings, lead apron, etc.) Superimposition of spine on other structures Asymmetrical placement of teeth Narrowed anterior teeth Films dirty or bent Vertical overlap of anterior teeth Occlusal plane tipped up Density too high Stains on film Film fogged Occlusal plane tipped down Patient movement
438* 263 235 227 197 149 I25 119 113 97 88 68 64 63 61 51 50 43 43 32 27 6
*Some films showed more than one type of mark
those of adequate diagnostic quality and 5.4 for those of inadequate or marginal quality. While radiographs judged diagnostically adequate had statistically significant fewer errors in all categories except processing than those judged inadequate or marginal, the major difference between adequate and inadequate radiographs was the severity, not the number of errors. The most frequent errors causing the radiograph to be judged inadequate, in order, were the presence of the vertebral column, improper density (usually too low), blurring and distortion of objects, and miscellaneous errors in processing and handling of the film. Other reasons for marginal or inadequate diagnostic quality included radiopaque areas or areas with low density, diagnostic information being cut off or superimposed, the presence of artifacts, bands, a dark shadow, and marks such as static, streaking, and contamination. DISCUSSION
Sixty-four different types of errors were encountered on the 500 panoramic radiographs evaluated. The only category of error listed on the rating form but not found in the sample was double exposure. Presumably if this error occurred, the radiograph would have been retaken before submission. A vari-
620
Brezden and Brooks
Fig.
Oral Surg. May. IV87
2. Example of panoramic radiograph that was judged to be diagnostically inadequate.
able that was not included on this rating form that may be added is whether the patient had the lips open as evidenced by a dark area superimposed on anterior crowns as a result of the air space between the open lips. This study confirmed the impression gained from discussion with personnel at DDPM that the quality of panoramic radiographs submitted is less than optimum. The average radiograph contained 4.7 technical errors. Only one radiograph was judged to contain no errors. This differs significantly from the results of the study published by Schiff and coworkers,I2 in which 20.3% were error free. The radiographs they evaluated were taken by a variety of unidentified persons, including students, faculty, and technicians. The faculty and technicians could presumably be considered experienced and aware of the requirements for making a good panoramic radiograph. The students, while less experienced, had the benefit of instruction in panoramic technique and possibly the motivation of grades to improve their performance. In the private office, in contrast, the training and experience of the operators are unknown. Many of the dentists entered practice before panoramic techniques were commonly taught in dental school. Few continuing education courses in panoramic techniques are offered through organizations and institutions listed in the Journal of the American Dental Association.16According to testimony given to the U.S. House of Representatives Subcommittee on Oversight and Investigation,” auxiliary personnel take more than 50% of the radiographs in the dental office. It was estimated that in 1979 as many as 100,000 of the 150,000 dental assistants in the United States who performed x-ray examinations were completely unlicensed. While some of these dental assistants may have had formal dental radiog-
raphy courses, many are trained on the job in the dental office. This situation has probably improved since 1979 as more states have instituted training requirements for licensure to take radiographs, but while institutions training auxiliary personnel have intraoral x-ray machines for their students to use, not all have panoramic equipment. It would have been helpful to ascertain the training and experience of the operators in this study to determine whether there is any correlation with radiographic quality, but this was not possible becausethe management at DDPM thought it would be an invasion of the privacy of the dentists who submitted radiographs since they were not expecting to be part of a research study when they filed for preauthorization or claim processing. Because the dentists were not contacted, it is not known whether errors were more frequently found with some machines than others or with manual versus automatic processing. However, the error rates were the same in the split image radiographs as in the continuous image radiographs. Some of the errors may have been caused by conditions beyond the operator’s control, such as the image of the spine being superimposed on the anterior teeth in the patient with a short heavy neck, but the processing errors and most of the positioning errors could have been avoided if more care had been given to the procedure. The value of training programs on radiographic quality has not been definitively proven.‘* It seems logical that offering instruction in a relatively new and unfamiliar technique would enable operators to produce better radiographs, yet even the trained technician in the study by Schiff and associates’*had at least one error on more than half of the radiographs. Not all errors are equally significant in reducing
Volume 63 Number 5
Evaluation
the diagnostic potential of the radiograph. A fogged radiograph may be so dark and monochromatic as to be virtually useless,while a radiograph that shows a static electricity artifact in a nonsignificant location may present no decrease in diagnostic value. An attempt was made to judge the usefulness of the submitted radiographs for diagnosis of the entire dentition and surrounding structures, but this is by nature a very subjective call. A radiograph may be blurred in the anterior region and judged inadequate, but it may be perfectly adequate for evaluation of the third molars. The primary purpose of the dentist in obtaining the radiograph was not determined in this study. It is possible that some of the radiographs judged to be marginal or inadequate could still have been useful in certain circumstances. The rating form used in this study was adequate for the purpose, but modification might improve it. The frequency and type of errors were well documented, but no provision was made for denoting the severity of error and its effect on the diagnostic usefulness of the radiograph. In addition, there were so many variations of certain types of errors, such as marks on the radiographs, that the form was cumbersome. Streamlining it would help if it were to be used by third party carriers to determine whether radiographs are adequate for the intended purpose and to offer suggestions to dentists for improvement.
2. Bean LR. Comparison of bisecting angle and paralleling methods of intraoral radiology. J Dent Educ 1969;33:441-5. 3. Mourshed F. A study of intraoral radiographic errors made by dental students. ORAL SURG ORAL MED ORAL PATHOL 1971;32:824-8. 4. Mourshed F, McKinney AL. A comparison of paralleling and bisecting radiographic techniques as experienced by dental students. ORAL SURG ORAL MED ORAL PATHOL 1972;33:28496. 5. Jensen TW. Improved reliability of dental radiography by application of x-ray beam-guiding instruments: a 2-year report. J Dent Educ 1978;42:481-5. 6. Pate1 JR. Intraoral radiographic errors. ORAL SUKC ORAI MED ORAL PATHOL 1979;48:479-83. I. Pate] JR, Greer DF. Evaluating student progress through error reduction in intraoral radiographic technique. ORAL SURG ORAL MED ORAL PATHOL 1986;62:471-4. 8. Beideman RW, Johnson ON, Alcox RW. A study to develop a rating system and evaluate dental radiographs submitted to a third party carrier. J Am Dent Assoc 1976;93:1010-3. 9. Grondahl HG, Hollender L, Osvald 0. Quality and quantity of dental x-ray examinations. A comparative study in a 5year interval. Dentomaxillofac Radio] 1980;9:70-2. IO. Nysether S, Hansen BF. Errors on dental bitewing radiographs. Community Dent Oral Epidemiol 1983;11:286-8. survey. Presented at the II. Kaugars GE. The Virginia-Florida annual meeting of the American Academy of Dental Radiology. 1984. 12. Schiff T, D’Ambrosio J, Glass BJ, Langlais RP, McDavid WD. Common positioning and technical errors in panoramic radiography. J Am Dent Assoc 1986;113:422-6. 13. Lanaland OE. Lanalais RP. Morris CR. Princinles and practice of panoramyc radiology. Philadelphia: W.B. Saunders Co, 1982. 14. Manson-Hing LR. Panoramic dental radiography. 2nd ed. Springfield, Illinois: Charles C Thomas, 1980. 15. Chomenko AG. Atlas for maxillofacial pantomographic interpretation. Chicago: Quintessence Publishing Co, 1985. 16. Department of Membership and Continuing Education Records. Continuing education course listing for June to December 1986. J Am Dent Assoc 1986;112:883-907. 17. Subcommittee on Oversight and Investigations, Committee on Interstate and Foreign Commerce, United States House of Representatives. Unnecessary exposure to radiation from medical and dental x-rays. Report 96-52, August 1980. 18. Department of Health and Human Services. Standards for the accreditation of educational programs for and the credentialing of radiologic personnel, 42 CFR Part 75. Federal Register, 50 (238):50710-50724, Dec. 1 I, 1985.
CONCLUSIONS
Panoramic radiographs taken in private dental offices show a large number of technical errors, some of which make the radiographs diagnostically useless. While the exact cause for the frequency of errors is not known, lack of familiarity with basic panoramic technique and lack of attention to details could be major contributors to the problem. This research was supported by the Delta Dental Fund. REFERENCES 1. Crandell CE. Cause and frequency of intraoral x-ray errors by dental hygiene students. J Dent Educ 1958;22:189-96.
of panoramic dental radiographs
Reprint requests to: Dr. Sharon L. Brooks University of Michigan School of Dentistry Department of Oral Diagnosis and Radiology Ann Arbor, MI 48109-1078
621
American Academy of Dental Radiology Department of Dental Diagnostic Sciences School of Dentistry, The University of Texas Health Science Center at San Antonio 7703 Floyd Curl Dr. San Antonio, Texas 78284
Evaluation of panoramic dental radiographs taken in private practice Natalia A. Brezden, B.S.,* and Sharon L. Brooks, D.D.S., M.S.,** Ann Arbor, Mich. UNIVERSITY
OF MICHIGAN
Five hundred panoramic radiographs submitted to Delta Dental Plan of Michigan for preauthorization or claim processing were evaluated for frequency of occurrence of 15 categories of technical errors in patient positioning, film processing, and general film handling. Only one radiograph showed no errors. The average radiograph contained 2.2 positioning errors, 1 .O processing errors, and 1.5 miscellaneous errors, for a total of 4.7 errors. Of the 500 radiographs, 467 had positioning errors, 441 had processing errors, and 424 had miscellaneous errors. Diagnostic quality was judged to be adequate in 365 radiographs, inadequate in 91 radiographs and marginal in 44 radiographs. The severity of error was of more importance than the number of errors in the determination of diagnostic adequacy. (ORAL SURG. ORAL MED. ORAL PATHOL. 1987;63:617-21)
H
igh quality radiographs are of vital importance to the practicing dentist as an aid in the proper diagnosis of patients’ dental needs. Artifacts and common technical errors, however, may cause the radiographs to be of marginal or inadequate diagnostic quality, leading to the potential of compromised dental care. Several studies have been published on the frequency of errors on intraoral radiographs taken by dental and dental hygiene students during their training in dental radiography.‘-’ Depending on the radiographic technique used, technical errors occurred on 7.6% to 49.9s4 of the films. Marked improvement in quality was noted as students advanced in their training.’ When Beideman and coworkers* evaluated intraoral radiographs taken in private dental offices and submitted to a third party carrier, they found that only 24.5% showed no technical errors. Even when *Dental student, Class of 1989. Oral Diagnosis and Radiology.
**Professor,
mounting errors were disregarded, only 44.7% were judged to be free of error. In Scandinavian countries, error rates for intraoral radiographs have been reported to be as high as 54% for periapical radiographs9 and 95.4% for bitewing radiographs.‘O In recent years, there has been a large increase in the use of panoramic radiography in dentistry.” Schiff and coworkers’* found that only about 20% of 1,000 randomly selected panoramic radiographs taken in a dental school by students, faculty, or technicians showed no positioning or other errors. A trained technician produced error-free panoramic radiographs 47% of the time. The purpose of this study was to evaluate the quality of panoramic radiographs taken in private dental offices in an effort to determine the need for continuing education in panoramic dental radiography. MATERIALS
AND METHODS
Textbooks on panoramic radiography’3-‘s were consulted in the development of a form to analyze the 617
616
Brezden and Brooks
Oral Surg. May, 1987
Error
Rate in 500 Panoramic from
Private
Radiographs
Practice
120 tn 5 100 i z g iii $
80
:1
20
80 40
0 0
1
9
2345678
Number
of Errors Fig.
quality of each panoramic radiograph screened.The rating factors included the following 15 categories of common errors: 1. A dark shadow above the tongue due to the patient not placing the tongue on the palate. 2. Vertical overlap of teeth due to the patient not biting on a bite block. 3. Artifacts such as lead aprons, dentures, jewelry, hearing aids, and eyeglasses. 4. Vertebral column causing extreme lightness in the anterior region as a result of the superimposed shadow of the spine. 5. Diagnostic information cut off at the lower border of the mandible or at the temporomandibular joint areas. Superimposition of diagnostic information caused by the spine overlapping the condyles or rami. 6. Double exposure. 7. Alternate vertical black and white bands caused by mechanical movements of the x-ray machine. 8. Blurring and distortion of objects (narrowing or widening of images) due to improper placement of the patient’s teeth in the focal trough, either anterior-posteriorly or asymmetrically, or incorrect setting of the profile index meter. 9. The occlusal plane tipped too far down or up, as evidenced by an extreme occlusal “smile” or “frown,” inward or outward tilting of the condyles, and the superimposition of the shadow of the palate on the apices of the maxillary teeth.
10
Per Radiograph
1.
10. Horizontal or vertical movement of patient during exposure, appearing as missing or doubled objects or abrupt shifting of image vertically. 11. A low- or high-density film from improper exposure (kVp) or processing. Fogged film with a uniform gray shade caused by excessive length of processing time, developing solutions that are too warm, excessive storage time or temperature, contaminated and/or depleted chemicals, or improper darkroom lighting. 12. Colored stains caused by accumulated chemicals and foreign material on the rollers of an automated processor. 13. Marks such as static electricity, dust or paper found in the screen, streaking due to processing error, and other marks such as crinkles, fingerprints, scratches, contamination, emulsion tears, water and chemical droplets, and others due to improper handling of the film. 14. Dirty or bent films. 15. Other errors, including films cut in size or cut in half and taped together, labels or paper left in the cassettes,film struck by light, uneven images on the films, etc. A subjective rating of diagnostic quality was also made, based on the significance of the errors and the degree they compromised the diagnostic usefulness of the radiograph. Before beginning the study, the investigators used the rating form developed to evaluate a series of panoramic radiographs several times to ensure con-
Volume 63 Number 5
Evaluation
sistency of judgment of errors. Periodically during the study, the original series was again reviewed and evaluated. Five hundred panoramic radiographs submitted for preauthorization or claim processing to Delta Dental Plan of Michigan (DDPM) in Southfield, Michigan, were reviewed by one of us for technical quality over an 8-week period. To eliminate bias in selection of radiographs, the caseswere evaluated in the order they were received at DDPM on the days chosen for site visits. The data collected were recorded on the rating form and later statistically analyzed by the Michigan Interactive Data Analysis System (MIDAS).
Table
RESULTS
Only one of the 500 panoramic radiographs evaluated had no technical errors present. Of the 499 panoramic radiographs with errors, 276 (55.2%) had 5 or more errors present and 223 (44.6%) had fewer than 5 errors present (Fig. 1). The average radiograph contained 2.2 positioning errors, 1.0 processing error, and 1.5 miscellaneous errors, for a total of 4.7 errors. Positioning mistakes, such as the dark shadow above the tongue, the blurring of anterior teeth, the presence of artifacts, the image of the vertebral column superimposed on the anterior teeth, and the position of the patient’s occlusal plane, accounted for errors on 467 radiographs. In addition, 441 radiographs had processing errors, which included stains and marks, and 424 radiographs had miscellaneous errors, which included diagnostic information being cut off or superimposed, an object missing or portrayed twice, improper density, and other problems in procedures and film handling. The frequency of occurrence of the most common errors is shown in Table I. Of the 500 panoramic radiographs, 414 (82.8%) were of dentulous patients, 8 (1.6%) were of edentulous patients, and 78 (15.6%) were of partially edentulous patients. This uneven distribution was due to selection of radiographs from a source used most often by persons with teeth. No relationship was found between the state of the dentition and the number of errors. In addition, no relationship was found between the type of panoramic machine, split versus continuous image, and the number of errors present. Diagnostic quality was judged to be adequate for 365 radiographs (73.0%), inadequate for 91 radiographs (18.2%), and marginal for 44 radiographs (8.8%). An example of a radiograph judged to be inadequate can be seen in Fig. 2. The average number of total errors per radiograph was 4.5 for
of panoramic dental radiographs
619
I. Frequency of errors in 500 panoramic radiographs Marks on film (fingerprints, scratches, etc.) Vertebral column superimposed on anterior teeth Shadow of airway above tongue Blurry anterior teeth Information cut off on edges of film Occlusal plane too flat Other miscellaneous errors Vertical bands from mechanical movement of x-ray machine Widened anterior teeth Density too low Radiopaque artifacts (earrings, lead apron, etc.) Superimposition of spine on other structures Asymmetrical placement of teeth Narrowed anterior teeth Films dirty or bent Vertical overlap of anterior teeth Occlusal plane tipped up Density too high Stains on film Film fogged Occlusal plane tipped down Patient movement
438* 263 235 227 197 149 I25 119 113 97 88 68 64 63 61 51 50 43 43 32 27 6
*Some films showed more than one type of mark
those of adequate diagnostic quality and 5.4 for those of inadequate or marginal quality. While radiographs judged diagnostically adequate had statistically significant fewer errors in all categories except processing than those judged inadequate or marginal, the major difference between adequate and inadequate radiographs was the severity, not the number of errors. The most frequent errors causing the radiograph to be judged inadequate, in order, were the presence of the vertebral column, improper density (usually too low), blurring and distortion of objects, and miscellaneous errors in processing and handling of the film. Other reasons for marginal or inadequate diagnostic quality included radiopaque areas or areas with low density, diagnostic information being cut off or superimposed, the presence of artifacts, bands, a dark shadow, and marks such as static, streaking, and contamination. DISCUSSION
Sixty-four different types of errors were encountered on the 500 panoramic radiographs evaluated. The only category of error listed on the rating form but not found in the sample was double exposure. Presumably if this error occurred, the radiograph would have been retaken before submission. A vari-
620
Brezden and Brooks
Fig.
Oral Surg. May. IV87
2. Example of panoramic radiograph that was judged to be diagnostically inadequate.
able that was not included on this rating form that may be added is whether the patient had the lips open as evidenced by a dark area superimposed on anterior crowns as a result of the air space between the open lips. This study confirmed the impression gained from discussion with personnel at DDPM that the quality of panoramic radiographs submitted is less than optimum. The average radiograph contained 4.7 technical errors. Only one radiograph was judged to contain no errors. This differs significantly from the results of the study published by Schiff and coworkers,I2 in which 20.3% were error free. The radiographs they evaluated were taken by a variety of unidentified persons, including students, faculty, and technicians. The faculty and technicians could presumably be considered experienced and aware of the requirements for making a good panoramic radiograph. The students, while less experienced, had the benefit of instruction in panoramic technique and possibly the motivation of grades to improve their performance. In the private office, in contrast, the training and experience of the operators are unknown. Many of the dentists entered practice before panoramic techniques were commonly taught in dental school. Few continuing education courses in panoramic techniques are offered through organizations and institutions listed in the Journal of the American Dental Association.16According to testimony given to the U.S. House of Representatives Subcommittee on Oversight and Investigation,” auxiliary personnel take more than 50% of the radiographs in the dental office. It was estimated that in 1979 as many as 100,000 of the 150,000 dental assistants in the United States who performed x-ray examinations were completely unlicensed. While some of these dental assistants may have had formal dental radiog-
raphy courses, many are trained on the job in the dental office. This situation has probably improved since 1979 as more states have instituted training requirements for licensure to take radiographs, but while institutions training auxiliary personnel have intraoral x-ray machines for their students to use, not all have panoramic equipment. It would have been helpful to ascertain the training and experience of the operators in this study to determine whether there is any correlation with radiographic quality, but this was not possible becausethe management at DDPM thought it would be an invasion of the privacy of the dentists who submitted radiographs since they were not expecting to be part of a research study when they filed for preauthorization or claim processing. Because the dentists were not contacted, it is not known whether errors were more frequently found with some machines than others or with manual versus automatic processing. However, the error rates were the same in the split image radiographs as in the continuous image radiographs. Some of the errors may have been caused by conditions beyond the operator’s control, such as the image of the spine being superimposed on the anterior teeth in the patient with a short heavy neck, but the processing errors and most of the positioning errors could have been avoided if more care had been given to the procedure. The value of training programs on radiographic quality has not been definitively proven.‘* It seems logical that offering instruction in a relatively new and unfamiliar technique would enable operators to produce better radiographs, yet even the trained technician in the study by Schiff and associates’*had at least one error on more than half of the radiographs. Not all errors are equally significant in reducing
Volume 63 Number 5
Evaluation
the diagnostic potential of the radiograph. A fogged radiograph may be so dark and monochromatic as to be virtually useless,while a radiograph that shows a static electricity artifact in a nonsignificant location may present no decrease in diagnostic value. An attempt was made to judge the usefulness of the submitted radiographs for diagnosis of the entire dentition and surrounding structures, but this is by nature a very subjective call. A radiograph may be blurred in the anterior region and judged inadequate, but it may be perfectly adequate for evaluation of the third molars. The primary purpose of the dentist in obtaining the radiograph was not determined in this study. It is possible that some of the radiographs judged to be marginal or inadequate could still have been useful in certain circumstances. The rating form used in this study was adequate for the purpose, but modification might improve it. The frequency and type of errors were well documented, but no provision was made for denoting the severity of error and its effect on the diagnostic usefulness of the radiograph. In addition, there were so many variations of certain types of errors, such as marks on the radiographs, that the form was cumbersome. Streamlining it would help if it were to be used by third party carriers to determine whether radiographs are adequate for the intended purpose and to offer suggestions to dentists for improvement.
2. Bean LR. Comparison of bisecting angle and paralleling methods of intraoral radiology. J Dent Educ 1969;33:441-5. 3. Mourshed F. A study of intraoral radiographic errors made by dental students. ORAL SURG ORAL MED ORAL PATHOL 1971;32:824-8. 4. Mourshed F, McKinney AL. A comparison of paralleling and bisecting radiographic techniques as experienced by dental students. ORAL SURG ORAL MED ORAL PATHOL 1972;33:28496. 5. Jensen TW. Improved reliability of dental radiography by application of x-ray beam-guiding instruments: a 2-year report. J Dent Educ 1978;42:481-5. 6. Pate1 JR. Intraoral radiographic errors. ORAL SUKC ORAI MED ORAL PATHOL 1979;48:479-83. I. Pate] JR, Greer DF. Evaluating student progress through error reduction in intraoral radiographic technique. ORAL SURG ORAL MED ORAL PATHOL 1986;62:471-4. 8. Beideman RW, Johnson ON, Alcox RW. A study to develop a rating system and evaluate dental radiographs submitted to a third party carrier. J Am Dent Assoc 1976;93:1010-3. 9. Grondahl HG, Hollender L, Osvald 0. Quality and quantity of dental x-ray examinations. A comparative study in a 5year interval. Dentomaxillofac Radio] 1980;9:70-2. IO. Nysether S, Hansen BF. Errors on dental bitewing radiographs. Community Dent Oral Epidemiol 1983;11:286-8. survey. Presented at the II. Kaugars GE. The Virginia-Florida annual meeting of the American Academy of Dental Radiology. 1984. 12. Schiff T, D’Ambrosio J, Glass BJ, Langlais RP, McDavid WD. Common positioning and technical errors in panoramic radiography. J Am Dent Assoc 1986;113:422-6. 13. Lanaland OE. Lanalais RP. Morris CR. Princinles and practice of panoramyc radiology. Philadelphia: W.B. Saunders Co, 1982. 14. Manson-Hing LR. Panoramic dental radiography. 2nd ed. Springfield, Illinois: Charles C Thomas, 1980. 15. Chomenko AG. Atlas for maxillofacial pantomographic interpretation. Chicago: Quintessence Publishing Co, 1985. 16. Department of Membership and Continuing Education Records. Continuing education course listing for June to December 1986. J Am Dent Assoc 1986;112:883-907. 17. Subcommittee on Oversight and Investigations, Committee on Interstate and Foreign Commerce, United States House of Representatives. Unnecessary exposure to radiation from medical and dental x-rays. Report 96-52, August 1980. 18. Department of Health and Human Services. Standards for the accreditation of educational programs for and the credentialing of radiologic personnel, 42 CFR Part 75. Federal Register, 50 (238):50710-50724, Dec. 1 I, 1985.
CONCLUSIONS
Panoramic radiographs taken in private dental offices show a large number of technical errors, some of which make the radiographs diagnostically useless. While the exact cause for the frequency of errors is not known, lack of familiarity with basic panoramic technique and lack of attention to details could be major contributors to the problem. This research was supported by the Delta Dental Fund. REFERENCES 1. Crandell CE. Cause and frequency of intraoral x-ray errors by dental hygiene students. J Dent Educ 1958;22:189-96.
of panoramic dental radiographs
Reprint requests to: Dr. Sharon L. Brooks University of Michigan School of Dentistry Department of Oral Diagnosis and Radiology Ann Arbor, MI 48109-1078
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