- Email: [email protected]
Serial bitewings — Two films versus four films
Serial bitewings -Two films versus four films William R. Stanmeyer, Captain (DC) USN,* Winthrop P. Smith, Captain (DC) USN**
and
T
he use of roentgenograms as an aid to diagnosis in dentistry is a recommended procedure. In such branches of dentistry as oral surgery, periodontics, and endodontics, the specialist usually insists that the patient return at definite specified times for follow-up roentgenograms. By comparing these with earlier films, he can determine to a great extent whether healing is progressing satisfactorily. With the recent advance of widespread programs of caries prevention, the follow-up (or serial) roentgenogram has become an important tool in the hands of the operative dentist. The use of fluorides in water supplies as a cariespreventive measure and the use of stannous fluoride incorporated in compatible pumice and/or applied as a topical solution for the prevention of new caries and the arrest of existing caries makes the use of serial bitewing films mandatory. Under the newer concepts of preventive dentistry, the decision to restore a carious surface of a tooth as determined by loss of translucency in a roentgenogram must be tempered by a history of that lesion. The days of indiscriminate removal of tooth structure are gone, for the progression of carious lesions can be arrested, and in many instances stopped, through the use of fluoride preventive programs. Serial bitewing films are not only an important aid in determining whether caries has been arrested, but they also are a source of information regarding the eficiency of a program of caries prevention. Some controversy has existed over the superiority of four periapical films for bitewing roentgenogram as compared to the regular bitewing films. Advocates of the four periapical films contend that, because of the normal curvature of the dental arches, roentgen rays emanating from one fixed position, as with the regular bitewing technique, will produce a roentgenogram with some overlapping interproximal contacts. The present study was made to determine the relative merits of the *United **United
States Naval Academy, Annapolis, Md. States Naval Submarine Base, New London,
Corm.
403
404
Stanmeyer
and Smith
O.K. ox. & O.P. ivarrh. 1967
two techniques in terms of diagnosis, radiation to the patient, film cost, and time spent by personnel in exposing, developing, and mounting the roentgenograms. METHOD
Seventy patients participated in the program. For each patient, a set of bitewing exposures was taken with the regular bitewing film. At the same visit, another set was taken with four periapical films, exposing the molar and premolar areas separately. The exposures were made by a. single technician, who was also responsible for developing and mounting. For all exposures, an X-R-M x-ray machine with a 16-inch anode distance was used. Rinn periapical and bitewing film of Type Class D, Speed Group 12.0 to 24.0 was used. To secure maximum contrast for caries diagnosis, the films were exposed at 65 kv. and 10 Ma. for 1.25 seconds. All films were developed at 68’ F. for 41/2 minutes and then properly fixed, washed, and dried. The four periapical bitewing films were mounted separately from the two film set; both sets were coded and circulated separately among ten dentists in such a manner that the two sets could not be compared and recall was impossible. The dentists were asked to examine all sets of roentgenograms with an x-ray view box and to record all carious lesions by tooth and surface. RESULTS Diagnosis
Nine of the ten examiners found that the four periapical bitewing films offered more caries diagnostic information than the regular two-film bitewing series. The number of patients in whom additional caries were diagnosed with the four-film set varied widely from examiner No. 10, who found caries in 5 per cent more patients, to examiner No. 9, who diagnosed caries in 50 per cent more patients. In all instances, the additional caries found were incipient and, in most instances, amounted to a single new surface. The maximum number of new carious surfaces found by any one examiner in any one patient was three. It was the consensus of all examiners that the four-film bitewing set offered a more suitable roentgenogram for diagnosis. cost
The cost of x-ray film was next computed using the price of film to a military dental activity when purchased from the Defense Medical Material Supply Agency. The bitewing film cost 7.4 cents and the periapical film 2.3 cents per film. The film cost was 14.8 cents for a regular two-film bitewing series and 9.3 cents for the bitewing series of four periapical films. To the cost of periapical film, however, must be added the cost of bitewing tabs. Paper tabs are available at 90 cents per hundred, or 0.9 cent each. This brings the total cost of a bitewing series of four periapical films to 12.9 cents, assuming that a new bitewing tab is used for each periapical films as compared to 14.8 cents for two regular bitewing films. Thus, the four-film series is 1.8 cents less expensive per patient than the regular two-film bitewing series.
Serial bitewings
Volume 23 Number 3
Chair
405
time
The total time required to seat the patient, wash the operator’s hands, place the film, and complete the exposure for a regular bitewing series of two films was 97 seconds. The total time to seat the patient, wash the operator’s hands, place four periapical films in adaptors, place the film in the mouth, and complete the exposure for a bitewing series of four periapical films was 206 seconds. Darkroom
time
The time required to unwrap two conventional bitewing films and place them in developing racks was 30 seconds, as compared to 52 seconds for four periapical films. Once the films were in the developing racks, the developing, fixing, washing, and drying times were identical for both sets. Mounting
time
The time required to mount a regular two-film as compared to 118 seconds for the four-film set.
bitewing
set was ‘73 seconds,
DISCUSSION
Each technique appears to have advantages and disadvantages. The four-film technique offers more diagnostic information, and the film cost is lower. The primary disadvantage is that it is more time consuming. It takes approximately 3 minutes more per patient to expose, develop, and mount a four-film bitewing set than it does to process completely a two-film bitewing series. For this increase in time, the dentist will be able to diagnose incipient caries in 5 to 50 per cent more of his patients. Radiation does not appear to be a problem in either technique. Within the design of this study, the actual radiation to the patient could not be measured but it might be interpolated from figures quoted by the Division of Radiological Health, Public Health Service, United States Department of Health, Education, and Welfare. That Division reported that in a twenty-two-film series, using a 16-inch anode distance, 10 Ma., 90 kv., and Class D film, the patient would receive 3.85 r measured in air. This would amount to 180 mr (in air) per exposure or 360 mr for each regular bitewing series. With the four-film bitewing series, the exposure would result in a total of 720 mr, with the greatest dosage in the first molar/second premolar area where, because of the diameter of this beam and its overlap, the dose would amount to 360 mr. The gonadal dose was measured as l/173,000 of the facial dose. It must be remembered that these are facial doses measured in air, and they are far below the maximum dosage allowed per week. With a properly filtered and collimated x-ray machine, the gonadal dose would be infinitesimally small. What, then, are the criteria for the two-film versus the four-film bitewing roentgenogram? The amount of radiation to which the patient is exposed is so small that, except in rare isolated instances, it need not be considered as a factor. The regular two-film bitewing set is adequate for older patients in whom caries activity has decreased. It is also adequate for use when the dentist is interested in determining only which teeth need immediate operative attention.
406
Stanmeyer
and Smith
O.S., 0.x. March,
& O.P. 1967
The two-film set may also be adequate for transient patients or where cariesprevention programs have not been instituted and the dentist needs roentgenograms for a general clinical examination. The four-film technique must he considered the only acceptable technique in research designed to report on caries activity. The four-film technique is necessary for more accura,te diagnosis, particularly in young patients. It is an important adjunct to the dentist who prescribes and provides a caries-prevention program for his patients and uses roentgenograms as an aid to determine caries activity, for it permits the dentist to determine more accurately the necessary frequency of stannous fluoride application. This technique is less expensive if only the cost of the film is taken into considera.tion, but it becomes mo’re expensive if time is translated into money. The one disadvantage of the four-film technique is time consumption. If twenty sets of four bitewing films are taken per day, the working time is increased by one hour. Using the same equations, the following correlation can be made between the number of roentgenograms taken and the additional time necessary to complete the four-film set : 25 patients ------____________ --------------_-_-11/4 hours 50 patients ___________________ ------------------al/, hours 100 patients -------------------------------------5 hours 125 patients __________________ ---------------____ 61, hours 150 patients __________________________ -__--------7vz hours hours 200 patients --------------------------------------lO In a large institution or military installation, where great numbers of patients are referred for x-ray examination each day, a point is soon reached where the x-ray technician’s time and the availability of equipment become critical and limiting factors. Even though the four-film set provides greater diagnostic information, it cannot be categorically stated that the patient is not being provided with adequate dental care when the regular two-film set is used. It must be remembered that all the additional carious teeth diagnosed with the four-film set were teeth with incipient caries and should not normally be restored. The additional diagnostic information in a general practitioner’s office can be classified as “nice to know” but not necessarily essential. SUMMARY
Serial bitewing roentgenograms taken at definite intervals are essential to the provision of good denta. care to patients in a. fluoride c&es-prevention program. The use of four periapical films instead of two bitewing films increases diagnostic information, is less expensive, and does not increase x-ray dosage levels to points of concern, but it does increase the time required for film exposure, developing, and mounting by approximately 3 minutes per patient.
and
T
he use of roentgenograms as an aid to diagnosis in dentistry is a recommended procedure. In such branches of dentistry as oral surgery, periodontics, and endodontics, the specialist usually insists that the patient return at definite specified times for follow-up roentgenograms. By comparing these with earlier films, he can determine to a great extent whether healing is progressing satisfactorily. With the recent advance of widespread programs of caries prevention, the follow-up (or serial) roentgenogram has become an important tool in the hands of the operative dentist. The use of fluorides in water supplies as a cariespreventive measure and the use of stannous fluoride incorporated in compatible pumice and/or applied as a topical solution for the prevention of new caries and the arrest of existing caries makes the use of serial bitewing films mandatory. Under the newer concepts of preventive dentistry, the decision to restore a carious surface of a tooth as determined by loss of translucency in a roentgenogram must be tempered by a history of that lesion. The days of indiscriminate removal of tooth structure are gone, for the progression of carious lesions can be arrested, and in many instances stopped, through the use of fluoride preventive programs. Serial bitewing films are not only an important aid in determining whether caries has been arrested, but they also are a source of information regarding the eficiency of a program of caries prevention. Some controversy has existed over the superiority of four periapical films for bitewing roentgenogram as compared to the regular bitewing films. Advocates of the four periapical films contend that, because of the normal curvature of the dental arches, roentgen rays emanating from one fixed position, as with the regular bitewing technique, will produce a roentgenogram with some overlapping interproximal contacts. The present study was made to determine the relative merits of the *United **United
States Naval Academy, Annapolis, Md. States Naval Submarine Base, New London,
Corm.
403
404
Stanmeyer
and Smith
O.K. ox. & O.P. ivarrh. 1967
two techniques in terms of diagnosis, radiation to the patient, film cost, and time spent by personnel in exposing, developing, and mounting the roentgenograms. METHOD
Seventy patients participated in the program. For each patient, a set of bitewing exposures was taken with the regular bitewing film. At the same visit, another set was taken with four periapical films, exposing the molar and premolar areas separately. The exposures were made by a. single technician, who was also responsible for developing and mounting. For all exposures, an X-R-M x-ray machine with a 16-inch anode distance was used. Rinn periapical and bitewing film of Type Class D, Speed Group 12.0 to 24.0 was used. To secure maximum contrast for caries diagnosis, the films were exposed at 65 kv. and 10 Ma. for 1.25 seconds. All films were developed at 68’ F. for 41/2 minutes and then properly fixed, washed, and dried. The four periapical bitewing films were mounted separately from the two film set; both sets were coded and circulated separately among ten dentists in such a manner that the two sets could not be compared and recall was impossible. The dentists were asked to examine all sets of roentgenograms with an x-ray view box and to record all carious lesions by tooth and surface. RESULTS Diagnosis
Nine of the ten examiners found that the four periapical bitewing films offered more caries diagnostic information than the regular two-film bitewing series. The number of patients in whom additional caries were diagnosed with the four-film set varied widely from examiner No. 10, who found caries in 5 per cent more patients, to examiner No. 9, who diagnosed caries in 50 per cent more patients. In all instances, the additional caries found were incipient and, in most instances, amounted to a single new surface. The maximum number of new carious surfaces found by any one examiner in any one patient was three. It was the consensus of all examiners that the four-film bitewing set offered a more suitable roentgenogram for diagnosis. cost
The cost of x-ray film was next computed using the price of film to a military dental activity when purchased from the Defense Medical Material Supply Agency. The bitewing film cost 7.4 cents and the periapical film 2.3 cents per film. The film cost was 14.8 cents for a regular two-film bitewing series and 9.3 cents for the bitewing series of four periapical films. To the cost of periapical film, however, must be added the cost of bitewing tabs. Paper tabs are available at 90 cents per hundred, or 0.9 cent each. This brings the total cost of a bitewing series of four periapical films to 12.9 cents, assuming that a new bitewing tab is used for each periapical films as compared to 14.8 cents for two regular bitewing films. Thus, the four-film series is 1.8 cents less expensive per patient than the regular two-film bitewing series.
Serial bitewings
Volume 23 Number 3
Chair
405
time
The total time required to seat the patient, wash the operator’s hands, place the film, and complete the exposure for a regular bitewing series of two films was 97 seconds. The total time to seat the patient, wash the operator’s hands, place four periapical films in adaptors, place the film in the mouth, and complete the exposure for a bitewing series of four periapical films was 206 seconds. Darkroom
time
The time required to unwrap two conventional bitewing films and place them in developing racks was 30 seconds, as compared to 52 seconds for four periapical films. Once the films were in the developing racks, the developing, fixing, washing, and drying times were identical for both sets. Mounting
time
The time required to mount a regular two-film as compared to 118 seconds for the four-film set.
bitewing
set was ‘73 seconds,
DISCUSSION
Each technique appears to have advantages and disadvantages. The four-film technique offers more diagnostic information, and the film cost is lower. The primary disadvantage is that it is more time consuming. It takes approximately 3 minutes more per patient to expose, develop, and mount a four-film bitewing set than it does to process completely a two-film bitewing series. For this increase in time, the dentist will be able to diagnose incipient caries in 5 to 50 per cent more of his patients. Radiation does not appear to be a problem in either technique. Within the design of this study, the actual radiation to the patient could not be measured but it might be interpolated from figures quoted by the Division of Radiological Health, Public Health Service, United States Department of Health, Education, and Welfare. That Division reported that in a twenty-two-film series, using a 16-inch anode distance, 10 Ma., 90 kv., and Class D film, the patient would receive 3.85 r measured in air. This would amount to 180 mr (in air) per exposure or 360 mr for each regular bitewing series. With the four-film bitewing series, the exposure would result in a total of 720 mr, with the greatest dosage in the first molar/second premolar area where, because of the diameter of this beam and its overlap, the dose would amount to 360 mr. The gonadal dose was measured as l/173,000 of the facial dose. It must be remembered that these are facial doses measured in air, and they are far below the maximum dosage allowed per week. With a properly filtered and collimated x-ray machine, the gonadal dose would be infinitesimally small. What, then, are the criteria for the two-film versus the four-film bitewing roentgenogram? The amount of radiation to which the patient is exposed is so small that, except in rare isolated instances, it need not be considered as a factor. The regular two-film bitewing set is adequate for older patients in whom caries activity has decreased. It is also adequate for use when the dentist is interested in determining only which teeth need immediate operative attention.
406
Stanmeyer
and Smith
O.S., 0.x. March,
& O.P. 1967
The two-film set may also be adequate for transient patients or where cariesprevention programs have not been instituted and the dentist needs roentgenograms for a general clinical examination. The four-film technique must he considered the only acceptable technique in research designed to report on caries activity. The four-film technique is necessary for more accura,te diagnosis, particularly in young patients. It is an important adjunct to the dentist who prescribes and provides a caries-prevention program for his patients and uses roentgenograms as an aid to determine caries activity, for it permits the dentist to determine more accurately the necessary frequency of stannous fluoride application. This technique is less expensive if only the cost of the film is taken into considera.tion, but it becomes mo’re expensive if time is translated into money. The one disadvantage of the four-film technique is time consumption. If twenty sets of four bitewing films are taken per day, the working time is increased by one hour. Using the same equations, the following correlation can be made between the number of roentgenograms taken and the additional time necessary to complete the four-film set : 25 patients ------____________ --------------_-_-11/4 hours 50 patients ___________________ ------------------al/, hours 100 patients -------------------------------------5 hours 125 patients __________________ ---------------____ 61, hours 150 patients __________________________ -__--------7vz hours hours 200 patients --------------------------------------lO In a large institution or military installation, where great numbers of patients are referred for x-ray examination each day, a point is soon reached where the x-ray technician’s time and the availability of equipment become critical and limiting factors. Even though the four-film set provides greater diagnostic information, it cannot be categorically stated that the patient is not being provided with adequate dental care when the regular two-film set is used. It must be remembered that all the additional carious teeth diagnosed with the four-film set were teeth with incipient caries and should not normally be restored. The additional diagnostic information in a general practitioner’s office can be classified as “nice to know” but not necessarily essential. SUMMARY
Serial bitewing roentgenograms taken at definite intervals are essential to the provision of good denta. care to patients in a. fluoride c&es-prevention program. The use of four periapical films instead of two bitewing films increases diagnostic information, is less expensive, and does not increase x-ray dosage levels to points of concern, but it does increase the time required for film exposure, developing, and mounting by approximately 3 minutes per patient.