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Clinical television research instrumentation
In clinical dental research, television instrum entation can be used to measure buccoproximal m arginal deterioration of dental restorations, to measure finite density changes of a specific region in clinical radiographs or historadiographs, or to control radiographic characteristics of impor tan t diagnostic regions.
Clinical television research instrumentation
Arthur I. Klein, DDS, MSD, Indianapolis The application of electronic and television en gineering technology to dental research is overdue. The impact that these technologies have had on our lives is obvious. More spectacular, however, are their accomplishments in space research, nu clear research, missile and military weapons re search, and biomedical research. These and more recent advancements in technology should be applied to the development of new dental re search methods, technics, and instrumentation. The operational theory of the application of television to dental research has been reported.1 Basically, the television instrumentation is used to obtain measured information from the tele vision image of the object of investigation. The television image is composed of a series of scan lines of various shades of gray that depict the viewed image. These shades of gray are the result of varying intensities of microvoltage that the television camera creates as it scans the image,
line by line. The ability of the developed instru mentation to measure the changes of microvolt ages (shades of gray) of any scan line or part of this scan line is the basis of the measurement system.2 The instrumentations and applications of television to clinical dental research discussed in this paper have been designed and developed at the Electronics Research Laboratories of the Indiana University School of Dentistry (Fig. 1). Intraoral television microscope Intraoral clinical dental research generally has been conducted with the naked eye or the limited magnification of a binocular loop. Bulky equip ment and the low light levels of the oral cavity make observations at higher magnification impos sible and accurate measurements improbable. The intraoral television microscope3 provides instru mentation to magnify a 1-mm. intraoral region 250 times. Linear measurement change of 2 ¡t, is readily made on accurate calibration of the equip-
Fig. ! ■ Electronics research laboratory and associated television instrumentation: intraoral television microscope ( A ) , television control console (B ), recording monitor camera (C ), oscilloscope television camera ( D ) , and digital readout and experimental electrophoresis tele vision Instrumentation (E) 1 210
2 Weeks
1212
6 Months
9 Months
ment. One application of this instrumentation, intraoral television micromeasurement of cavity margin deterioration4 is shown in Figure 2. In this study, the buccoproximal marginal deteriora tion of 51 mesioocclusal alloy restorations of deciduous second molars were serially and peri odically measured and evaluated over 9 months. The data indicated that the gingival region of the proximal margin deteriorated faster during the first 12 weeks, whereas the occlusal region broke down at an increased rate during the last 24 weeks. The instrumentation can be modified to improve the investigator’s accuracy of repeated return to the location of measurement, making it possible to study the entire restoration margin. In this technic of macroscopic image identification (Fig. 3), an additional television camera is attached to the television microscope, which contains a fiber optic system that views the macroscopic image of the restoration margin. The macroscopic camera views the entire margin of the tooth while a portion of that margin is studied microscopically by the intraoral television microscope. The in tense spot of light from the microscopic unit iden tifies the region of study on the macroscopic im age. A specifically designed electromechanical shutter eliminates movement of the patient. The macroscopic and microscopic images are com bined by means of a special effects generator and stored simultaneously on a video tape recorder. The restoration margin of study observed microsconically is therefore identified macroscopically. Both images can then be viewed in stop-motion playback of the video tape recording for measure ment of the marginal deterioration.
Television subtraction readout The television subtraction readout instrumenta tion (Fig. 4) consists of a two-camera closedcircuit television system that is focused on
duplicate radiographic information (headplates, periapical film, and so forth). One camera provides a negative television image while the other camera provides a positive image. Both video signals are supplied to the multipurpose video mixer-switcher where the operator has complete control of elec tronically altering the density, contrast, bright ness, and image reversal of the original radiographic information. Therefore, radiographic shadows of overlying and underlying anatomic structures can be enhanced or eliminated to im prove the radiographic characteristics of the re gion of diagnostic importance. The operator may also more closely examine a particular region of the radiograph by initially determining the optical and electronic magnification to be combined with this application. Serial radiographs may be studied in the same manner by electronic superimposi tion of the original radiograph viewed as a nega tive signal with the succeeding radiograph super imposed as a positive signal. This electronic superimposition gives the investigator an excellent view of radiographic change in a region that may be ordinarily difficult to view and interpret radiographically. This instrumentation was used in the study, “A Clinical Television Radiographic Evaluation of Spongy Bone Architecture of the Edentulous Mandible.”5 The purpose of the investigation was to count bone trabeculae and medullary spaces and to measure maximum cross-section diameters of these medullary spaces in a standardized sam ple region from clinical radiographs of edentulous patients. A standardized 5-mm. molar and pre molar sample area of periapical radiographs from 27 patients without dentures and 39 patients with edentulous mandibles who wore dentures were evaluated. An analysis of the data indicates that there was no correlation between the average number of bone trabeculae or average number of medullary spaces in the patients with dentures or the patients without dentures. An increase of 17 to 27 percent in the average medullary space
Fig. 2 ■ Top left: Clinical application of intraoral instrumentation. Operator uses electrocular (1 ) as a television view ing device to focus microscope ( 2 ) . Top right: Relationship between gold overlay containing occlusal (3 ) and gingival marginal (4 ) viewing holes, through which the microscope objective lens is focused for serial marginal deterioration meas urements. Center: Am algam (A ) and enamel (E) are identified on restored tooth margin. Line o f marginal micromeasure ment is indicated by series of white dots through restoration margin. Space between each of these dots is calibrated to be 1 0 Region of marginal deterioration, indicated by arrow, begins 2 weeks postoperatively with complete marginal loss at 9 months. Dashed line indicates gradual fracture of occlusal-buccoproximal marginal region, which did not become clinically evident until 9 months postoperatively. Bottom: Schematic block diagram shows operation of instrumentation. High-intensity light system is focused as pinpoint of light on tooth margin through Leitz ultrapack microscope. Reflected marginal image is viewed through television viewing camera for focusing microscope. W hen marginal image is focused, foot control is used to activate electronic flash synchronizer and expose permachon (electronic memory) television camera through shutter and prism assembly. Electronically stored image of margin is then measured by scan line measurement system Klein: TELEVISION RESEARCH IN S T R U M E N T A T IO N
■ 1213
Fig. 3 ■ Macroscopic image identification: Intraoral microscope television camera views microscopic region image of restored margin simultaneously with fiber optic macroscopic television camera viewing macroscopic image, which are observed on their individual monitors. Macroscopic image identifies region of microscopic measurement by intense spot of light used as light source for intraoral microscope. Specifically designed electromechanical synchronized shutter reduces image movement of patient. Microscopic and macroscopic images are combined. Therefore, identifying region of measurement as entire restored margin is viewed and video tape recorded for future scan line measurement
Fig. 4 ■ Television subtraction readout: Electronic mixing of normal radiographic or positive televison image (A ) with negative television image (B) from duplicate radiograph creates subtraction image (C ). Subtraction image enables clin ician to enhance radiographic characteristics of region of diagnostic importance. Note diffused outline of mesial pulphorn and apparent caries exposure on normal radiograph ( A ) . Subtraction image (C ) definitely defines mesial pulphorn and delineates extent of caries as nonexposure. Pulp chamber, root canal, and crown appear in three-dim en sion effect. Normal radiograph (lateral view) of mandible bone specimen region (D ) with end view photograph of specimen (E ), in which series of holes were made. Holes do not appear clinically evident in white circular area of radiograph (D ). Television multiple subtraction technic ( F ) , consisting of mixing positive and negative image of region inside and outside electronically created circle, readily identifies region of hole in bone. Two television cameras are used for instrumentations (G ). One camera (1 ) views negative image and another camera (1 ) views positive image. Both cameras are coupled to two calibrated optollners (2 ) as constant light sources for backlighting viewed radio graphs that are carried in optoliners 1 214
1215
Fig. 5 ■ M ic ro ra d io g ra p h ic density in s tru m e n ta tio n : H isto ra d io g ra p h ic u n it can id e n tify and measure changes in density (c a lc ific a tio n ) o f h istoradiograph in 1/t region a t 1 ,8 0 0 X m a g n ific a tio n . Inset television m o n ito r photograph o f histo ra d io g rap h o f d e n tin indicates scan line o f m easurem ent (w h ite lin e ) and w h ite dot (a rro w ) id e n tifie s region of d e n sity m easurem ent made in p e ritu b u la r ring o f d e n tin tu b u le . R elative density is inserted in television p ictu re as d ig ita l readout display. T w o television cameras, one vie w in g d ig ita l readout (A ) and a n o th e r vie w in g histo ra d io g rap h ic im age ( B ) , are used in in stru m e n tatio n
width was noted for the group without dentures compared with that of the group with dentures.
M icroscopic and macroscopic linear and density radiographic instrum entation The instrumentation was developed to facilitate the measurement of finite density change of a particular region in clinical serial radiographic 1 2 1 6 ■ J A D A , V o l. 7 4 , M a y 1967
studies or at the microscopic level of historadio graphic investigations. Density readings are a logarithmic function; however, to determine the percentage of density change in a particular area of a radiograph, the density information must be converted to a linear function. This conversion is accomplished by the linear density converter dis play unit, which converts the density information of a particular scan line or portion of the line to linear information. The microscopic and macro scopic instrumentations are essentially identical electronically, differing only in the initial optical
m a g n i f i c a t i o n of the image viewed by the tele vision camera. The image is processed by means of the scan line measurement, linear density con verter, and multipurpose video mixer-switcher instrumentations to the master monitor where the regions of measurement are determined by the investigator. The microradiographic instru mentation (Fig. 5) can identify and measure changes in the density of historadiographs in an area of 1^ at 1,800X magnification. The macro radiographic unit (Fig. 6) can identify and meas ure density and linear change from clinical radio graphs at 10 X magnification. A macroscopic television evaluation6 of the effectiveness of zinc oxide-eugenol and calcium hydroxide methylcellulose base materials for in direct pulp-capping procedures was accomplished by the measurement of calcification change of the dentin between the indirect pulp-capping material and the pulp chamber. The data from periapical radiographs of 35 teeth treated with calcium hy droxide methylcellulose and 41 teeth treated with zinc oxide-eugenol at 3, 6, and 12 months in dicate only a slight difference in increased radiopacity (calcification) in the overlying pulpal den tin after the use of either indirect pulp-capping material. The increased radiopacity was usually only evident with the more sensitive television macroscopic density instrumentation. The microradiographic instrumentation was used in the evaluation of dentinal sclerosis in deciduous teeth.7 The microradiographs were pre pared from ground sections precisely oriented to the regions of sclerosis shown on the clinical radiograph. During the measurement and study of these regions of dental sclerosis, evidence of a rhythmic hypercalcificatiori was noted and de scribed as a zone of hypercalcified matrix, zone of moderate matrix calcification, or zone of tu bule obliteration.
Other research applications of television instrum entation
and home care procedures in the treatment of periodontal disease. These micromeasurement changes, in terms of gingival tissue height and tone, can also be investigated for their relation ship to gingivitis, periodontal surgery (preoperatively and postoperatively), and orthodontic treat ment (pretreatment, during treatment, and posttreatment). The macroscopic instrumentation and the sub traction readout system could be combined to de termine more accurate growth and calcification factors of the bones of the face along with erup tion and calcification rates of the developing per manent dentition. Macroscopic observations of two separate cephalometrically produced and elec tronically superimposed video-taped images would make it possible to simultaneously electronically correlate anatomic dynamic function of the oral mechanism with the soft tissue profile. The soft tissue profile would be television-taped simultane ously with a direct radiographic (fluoroscopic) image on a specifically designed television tape recorder. This technic would be of more value in the study of the masticatory process before im mediate complete denture construction compared with periodic postoperative evaluations, and be fore orthodontic treatment in patients with tongue thrust compared with periodic posttreatment eval uation. The television microdensitometric instrumenta tion can be used to determine critically the amount of stain absorption of various cells relative to a known standard during the evaluation of histo logic, histochemical, and pathologic studies. This instrumentation, combined with the subtraction readout technic and use of specifically designed electronic comparison density wedges, can be used to evaluate critically calcification changes in an area of 1^ of historadiographs from dentin of teeth involved in endodontic and operative procedures, bone healing and bone growth studies, and tooth development studies. Sum m ary
The preceding television instrumentations can be modified and redesigned for other dental investi gations. The intraoral television microscope could be of value in other marginal deterioration studies of newly developed restorative materials and ex perimental cavity preparation designs. A modi fied version of the instrumentation could be de veloped to correlate micromeasurement changes of the superficial gingival tissue capillary vessel dilation-contraction in response to the clinical
The application of electronic and television en gineering technology to dental research is overdue. Some of these technics have been modified, de veloped, and redesigned to create instrumenta tion for dental research. Instrumentation is as follows: ■ Intraoral television micromeasurement: Intra oral instrumentation measures progressively serial Klein: TELEVISIO N RESEARCH IN S T R U M E N T A T IO N ■ 1217
****** M M *
Fig. 6 ■ C lin ic a l density in s tru m e n ta tio n : T h is u n it can id e n tify and m easure lin e a r and density (c a lc ific a tio n ) changes from c lin ic a l radiograph a t 10 X m a g n ific a tio n . Television m o n ito r photograph (inset) id e n tifie s scan line o f meas ure m e n t (w h ite lin e ) a nd indicates region o f m easurem ent as w h ite d o t (a rro w ). Relative change in density (c a lc i fic a tio n ) o f d e n tin is inserted in television p ic tu re as d ig ita l readout display. Radiographic step wedge in c lin ic a l ra d io graph is used to c a lib ra te density response o f television equ ip m e n t. T w o te le visio n cameras (A ) and (C ) are used in in stru m e n ta tio n . One cam era views c lin ic a l radiograph in o p to lin e r (B) a nd a n other camera views relative density d ig ita l readout (D )
buccoproximal marginal deterioration of den tal restorations. This instrumentation can intraorally record a linear change as small as 2 ^ in marginal deterioration. ■ Television subtraction readout: This instru mentation allows the operator to control elec 1 218 ■ JA D A , V o l. 7 4 , M a y 1967
tronically the density, contrast, brightness, and image reversal of original radiographic informa tion. Therefore, radiographic shadows of overlying and underlying anatomic structures can be enhanced or eliminated to improve the radiographic characteristics of the region of diagnostic importance.
■ Microradiographic and macroradiographic den sity measurement instrumentation: The instrumen tation can identify and measure changes in den sity of historadiographs in an area of 1/x at 1,800X magnification. The clinical macroradiographic unit can identify and measure the density and linear change from clinical radiographs at 10 X magni fication.
D octor Klein is an assistant professor o f pedodontics, In diana U n ive rsity School o f D e n tistry, 1 121 W e st M ic h igan St., Indianapolis, 4 6 2 0 2 . 1. Klein, A . I. The television microscope in d e ntal re search. Dent Prog 2 :2 7 4 Ju ly, 1963. 2. Klein, A . I., and M acPherson, D w ig h t. Television m easurem ent pulse g e n e ra to r-m ixe r. J M ed E lectm c Biol Engng 5 : In press. 3. Klein, A . I.,a n d M acPherson, D w ight. In tra o ra l te le vision m icrom easurem ent in stru m e n ta tio n . J M ed Elec trn c Biol Engng 5 :ln press. 4. H o rw itz, B. A . In tra o ra l television m icrom easure m en t o f ca vity m a rg in d e te rio ra tio n . Thesis, Indiana U n ive rsity School o f D e n tistry, 1966.
T he a u th o r th a nks M r. D w ig h t MacPherson fo r as sisting in th e developm ent and operation o f the television in s tru m e n ta tio n , Doctor Burton H o rw itz fo r pro vid in g the serial television in tra o ra l m icrom easurem ent occlusal hole photographs o f a Class II a llo y restoration, Doctor Jules G eller fo r p ro vid in g the c lin ic a l radiographs, Doc to r A n to n io d e A g u ia r fo r pro vid in g the bone ra d io graphs, and M r. Richard Scott fo r preparing th e illu s tra tiv e m a te ria l. T h is in ve stig a tion was supported in p a rt by USPHS research g ra n t D E -0 1 8 1 3 from th e N a tio n a l In stitu te s o f H e a lth , Bethesda, M d.
5. d e A g u ia r^ A . E. C lin ic a l television rad io g ra p hic eva lu a tion o f spongy bone a rc h ite c tu re in the e d e n tu lous m andible. Thesis, In d ia na U n ive rsity School o f D e n tistry, 1966. 6. Kerkhove, B. C. C lin ic a l and television densitom e tric e va lu a tion o f the in d ire c t p u lp capping technique. Thesis, In diana U n ive rsity School o f D entistry, 1965. 7. Klein, A . I. T elevision m icro d e n sito m e tric h is tio radiographic e va lu a tion o f d e n tin a l sclerosis in p rim a ry teeth. Paper presented a t th e A m e rican A cadem y o f Pedodontics, P hila d e lp h ia , Oct. 11, 1961.
V is ito rs a tte n d in g the a n n ual session in W ash in n ton , D.C., O ctober 2 9 -N o ve m b e r 2, w ho have th e tim e, w ill enjoy a v is it to M o u n t V e r non, home o f George W a sh in g to n, w hich can be reached by ca r or bus via the M o u n t V ernon M e m o ria l H ighw ay
Klein: TELEVISIO N RESEARCH IN S T R U M E N T A T IO N
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Clinical television research instrumentation
Arthur I. Klein, DDS, MSD, Indianapolis The application of electronic and television en gineering technology to dental research is overdue. The impact that these technologies have had on our lives is obvious. More spectacular, however, are their accomplishments in space research, nu clear research, missile and military weapons re search, and biomedical research. These and more recent advancements in technology should be applied to the development of new dental re search methods, technics, and instrumentation. The operational theory of the application of television to dental research has been reported.1 Basically, the television instrumentation is used to obtain measured information from the tele vision image of the object of investigation. The television image is composed of a series of scan lines of various shades of gray that depict the viewed image. These shades of gray are the result of varying intensities of microvoltage that the television camera creates as it scans the image,
line by line. The ability of the developed instru mentation to measure the changes of microvolt ages (shades of gray) of any scan line or part of this scan line is the basis of the measurement system.2 The instrumentations and applications of television to clinical dental research discussed in this paper have been designed and developed at the Electronics Research Laboratories of the Indiana University School of Dentistry (Fig. 1). Intraoral television microscope Intraoral clinical dental research generally has been conducted with the naked eye or the limited magnification of a binocular loop. Bulky equip ment and the low light levels of the oral cavity make observations at higher magnification impos sible and accurate measurements improbable. The intraoral television microscope3 provides instru mentation to magnify a 1-mm. intraoral region 250 times. Linear measurement change of 2 ¡t, is readily made on accurate calibration of the equip-
Fig. ! ■ Electronics research laboratory and associated television instrumentation: intraoral television microscope ( A ) , television control console (B ), recording monitor camera (C ), oscilloscope television camera ( D ) , and digital readout and experimental electrophoresis tele vision Instrumentation (E) 1 210
2 Weeks
1212
6 Months
9 Months
ment. One application of this instrumentation, intraoral television micromeasurement of cavity margin deterioration4 is shown in Figure 2. In this study, the buccoproximal marginal deteriora tion of 51 mesioocclusal alloy restorations of deciduous second molars were serially and peri odically measured and evaluated over 9 months. The data indicated that the gingival region of the proximal margin deteriorated faster during the first 12 weeks, whereas the occlusal region broke down at an increased rate during the last 24 weeks. The instrumentation can be modified to improve the investigator’s accuracy of repeated return to the location of measurement, making it possible to study the entire restoration margin. In this technic of macroscopic image identification (Fig. 3), an additional television camera is attached to the television microscope, which contains a fiber optic system that views the macroscopic image of the restoration margin. The macroscopic camera views the entire margin of the tooth while a portion of that margin is studied microscopically by the intraoral television microscope. The in tense spot of light from the microscopic unit iden tifies the region of study on the macroscopic im age. A specifically designed electromechanical shutter eliminates movement of the patient. The macroscopic and microscopic images are com bined by means of a special effects generator and stored simultaneously on a video tape recorder. The restoration margin of study observed microsconically is therefore identified macroscopically. Both images can then be viewed in stop-motion playback of the video tape recording for measure ment of the marginal deterioration.
Television subtraction readout The television subtraction readout instrumenta tion (Fig. 4) consists of a two-camera closedcircuit television system that is focused on
duplicate radiographic information (headplates, periapical film, and so forth). One camera provides a negative television image while the other camera provides a positive image. Both video signals are supplied to the multipurpose video mixer-switcher where the operator has complete control of elec tronically altering the density, contrast, bright ness, and image reversal of the original radiographic information. Therefore, radiographic shadows of overlying and underlying anatomic structures can be enhanced or eliminated to im prove the radiographic characteristics of the re gion of diagnostic importance. The operator may also more closely examine a particular region of the radiograph by initially determining the optical and electronic magnification to be combined with this application. Serial radiographs may be studied in the same manner by electronic superimposi tion of the original radiograph viewed as a nega tive signal with the succeeding radiograph super imposed as a positive signal. This electronic superimposition gives the investigator an excellent view of radiographic change in a region that may be ordinarily difficult to view and interpret radiographically. This instrumentation was used in the study, “A Clinical Television Radiographic Evaluation of Spongy Bone Architecture of the Edentulous Mandible.”5 The purpose of the investigation was to count bone trabeculae and medullary spaces and to measure maximum cross-section diameters of these medullary spaces in a standardized sam ple region from clinical radiographs of edentulous patients. A standardized 5-mm. molar and pre molar sample area of periapical radiographs from 27 patients without dentures and 39 patients with edentulous mandibles who wore dentures were evaluated. An analysis of the data indicates that there was no correlation between the average number of bone trabeculae or average number of medullary spaces in the patients with dentures or the patients without dentures. An increase of 17 to 27 percent in the average medullary space
Fig. 2 ■ Top left: Clinical application of intraoral instrumentation. Operator uses electrocular (1 ) as a television view ing device to focus microscope ( 2 ) . Top right: Relationship between gold overlay containing occlusal (3 ) and gingival marginal (4 ) viewing holes, through which the microscope objective lens is focused for serial marginal deterioration meas urements. Center: Am algam (A ) and enamel (E) are identified on restored tooth margin. Line o f marginal micromeasure ment is indicated by series of white dots through restoration margin. Space between each of these dots is calibrated to be 1 0 Region of marginal deterioration, indicated by arrow, begins 2 weeks postoperatively with complete marginal loss at 9 months. Dashed line indicates gradual fracture of occlusal-buccoproximal marginal region, which did not become clinically evident until 9 months postoperatively. Bottom: Schematic block diagram shows operation of instrumentation. High-intensity light system is focused as pinpoint of light on tooth margin through Leitz ultrapack microscope. Reflected marginal image is viewed through television viewing camera for focusing microscope. W hen marginal image is focused, foot control is used to activate electronic flash synchronizer and expose permachon (electronic memory) television camera through shutter and prism assembly. Electronically stored image of margin is then measured by scan line measurement system Klein: TELEVISION RESEARCH IN S T R U M E N T A T IO N
■ 1213
Fig. 3 ■ Macroscopic image identification: Intraoral microscope television camera views microscopic region image of restored margin simultaneously with fiber optic macroscopic television camera viewing macroscopic image, which are observed on their individual monitors. Macroscopic image identifies region of microscopic measurement by intense spot of light used as light source for intraoral microscope. Specifically designed electromechanical synchronized shutter reduces image movement of patient. Microscopic and macroscopic images are combined. Therefore, identifying region of measurement as entire restored margin is viewed and video tape recorded for future scan line measurement
Fig. 4 ■ Television subtraction readout: Electronic mixing of normal radiographic or positive televison image (A ) with negative television image (B) from duplicate radiograph creates subtraction image (C ). Subtraction image enables clin ician to enhance radiographic characteristics of region of diagnostic importance. Note diffused outline of mesial pulphorn and apparent caries exposure on normal radiograph ( A ) . Subtraction image (C ) definitely defines mesial pulphorn and delineates extent of caries as nonexposure. Pulp chamber, root canal, and crown appear in three-dim en sion effect. Normal radiograph (lateral view) of mandible bone specimen region (D ) with end view photograph of specimen (E ), in which series of holes were made. Holes do not appear clinically evident in white circular area of radiograph (D ). Television multiple subtraction technic ( F ) , consisting of mixing positive and negative image of region inside and outside electronically created circle, readily identifies region of hole in bone. Two television cameras are used for instrumentations (G ). One camera (1 ) views negative image and another camera (1 ) views positive image. Both cameras are coupled to two calibrated optollners (2 ) as constant light sources for backlighting viewed radio graphs that are carried in optoliners 1 214
1215
Fig. 5 ■ M ic ro ra d io g ra p h ic density in s tru m e n ta tio n : H isto ra d io g ra p h ic u n it can id e n tify and measure changes in density (c a lc ific a tio n ) o f h istoradiograph in 1/t region a t 1 ,8 0 0 X m a g n ific a tio n . Inset television m o n ito r photograph o f histo ra d io g rap h o f d e n tin indicates scan line o f m easurem ent (w h ite lin e ) and w h ite dot (a rro w ) id e n tifie s region of d e n sity m easurem ent made in p e ritu b u la r ring o f d e n tin tu b u le . R elative density is inserted in television p ictu re as d ig ita l readout display. T w o television cameras, one vie w in g d ig ita l readout (A ) and a n o th e r vie w in g histo ra d io g rap h ic im age ( B ) , are used in in stru m e n tatio n
width was noted for the group without dentures compared with that of the group with dentures.
M icroscopic and macroscopic linear and density radiographic instrum entation The instrumentation was developed to facilitate the measurement of finite density change of a particular region in clinical serial radiographic 1 2 1 6 ■ J A D A , V o l. 7 4 , M a y 1967
studies or at the microscopic level of historadio graphic investigations. Density readings are a logarithmic function; however, to determine the percentage of density change in a particular area of a radiograph, the density information must be converted to a linear function. This conversion is accomplished by the linear density converter dis play unit, which converts the density information of a particular scan line or portion of the line to linear information. The microscopic and macro scopic instrumentations are essentially identical electronically, differing only in the initial optical
m a g n i f i c a t i o n of the image viewed by the tele vision camera. The image is processed by means of the scan line measurement, linear density con verter, and multipurpose video mixer-switcher instrumentations to the master monitor where the regions of measurement are determined by the investigator. The microradiographic instru mentation (Fig. 5) can identify and measure changes in the density of historadiographs in an area of 1^ at 1,800X magnification. The macro radiographic unit (Fig. 6) can identify and meas ure density and linear change from clinical radio graphs at 10 X magnification. A macroscopic television evaluation6 of the effectiveness of zinc oxide-eugenol and calcium hydroxide methylcellulose base materials for in direct pulp-capping procedures was accomplished by the measurement of calcification change of the dentin between the indirect pulp-capping material and the pulp chamber. The data from periapical radiographs of 35 teeth treated with calcium hy droxide methylcellulose and 41 teeth treated with zinc oxide-eugenol at 3, 6, and 12 months in dicate only a slight difference in increased radiopacity (calcification) in the overlying pulpal den tin after the use of either indirect pulp-capping material. The increased radiopacity was usually only evident with the more sensitive television macroscopic density instrumentation. The microradiographic instrumentation was used in the evaluation of dentinal sclerosis in deciduous teeth.7 The microradiographs were pre pared from ground sections precisely oriented to the regions of sclerosis shown on the clinical radiograph. During the measurement and study of these regions of dental sclerosis, evidence of a rhythmic hypercalcificatiori was noted and de scribed as a zone of hypercalcified matrix, zone of moderate matrix calcification, or zone of tu bule obliteration.
Other research applications of television instrum entation
and home care procedures in the treatment of periodontal disease. These micromeasurement changes, in terms of gingival tissue height and tone, can also be investigated for their relation ship to gingivitis, periodontal surgery (preoperatively and postoperatively), and orthodontic treat ment (pretreatment, during treatment, and posttreatment). The macroscopic instrumentation and the sub traction readout system could be combined to de termine more accurate growth and calcification factors of the bones of the face along with erup tion and calcification rates of the developing per manent dentition. Macroscopic observations of two separate cephalometrically produced and elec tronically superimposed video-taped images would make it possible to simultaneously electronically correlate anatomic dynamic function of the oral mechanism with the soft tissue profile. The soft tissue profile would be television-taped simultane ously with a direct radiographic (fluoroscopic) image on a specifically designed television tape recorder. This technic would be of more value in the study of the masticatory process before im mediate complete denture construction compared with periodic postoperative evaluations, and be fore orthodontic treatment in patients with tongue thrust compared with periodic posttreatment eval uation. The television microdensitometric instrumenta tion can be used to determine critically the amount of stain absorption of various cells relative to a known standard during the evaluation of histo logic, histochemical, and pathologic studies. This instrumentation, combined with the subtraction readout technic and use of specifically designed electronic comparison density wedges, can be used to evaluate critically calcification changes in an area of 1^ of historadiographs from dentin of teeth involved in endodontic and operative procedures, bone healing and bone growth studies, and tooth development studies. Sum m ary
The preceding television instrumentations can be modified and redesigned for other dental investi gations. The intraoral television microscope could be of value in other marginal deterioration studies of newly developed restorative materials and ex perimental cavity preparation designs. A modi fied version of the instrumentation could be de veloped to correlate micromeasurement changes of the superficial gingival tissue capillary vessel dilation-contraction in response to the clinical
The application of electronic and television en gineering technology to dental research is overdue. Some of these technics have been modified, de veloped, and redesigned to create instrumenta tion for dental research. Instrumentation is as follows: ■ Intraoral television micromeasurement: Intra oral instrumentation measures progressively serial Klein: TELEVISIO N RESEARCH IN S T R U M E N T A T IO N ■ 1217
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Fig. 6 ■ C lin ic a l density in s tru m e n ta tio n : T h is u n it can id e n tify and m easure lin e a r and density (c a lc ific a tio n ) changes from c lin ic a l radiograph a t 10 X m a g n ific a tio n . Television m o n ito r photograph (inset) id e n tifie s scan line o f meas ure m e n t (w h ite lin e ) a nd indicates region o f m easurem ent as w h ite d o t (a rro w ). Relative change in density (c a lc i fic a tio n ) o f d e n tin is inserted in television p ic tu re as d ig ita l readout display. Radiographic step wedge in c lin ic a l ra d io graph is used to c a lib ra te density response o f television equ ip m e n t. T w o te le visio n cameras (A ) and (C ) are used in in stru m e n ta tio n . One cam era views c lin ic a l radiograph in o p to lin e r (B) a nd a n other camera views relative density d ig ita l readout (D )
buccoproximal marginal deterioration of den tal restorations. This instrumentation can intraorally record a linear change as small as 2 ^ in marginal deterioration. ■ Television subtraction readout: This instru mentation allows the operator to control elec 1 218 ■ JA D A , V o l. 7 4 , M a y 1967
tronically the density, contrast, brightness, and image reversal of original radiographic informa tion. Therefore, radiographic shadows of overlying and underlying anatomic structures can be enhanced or eliminated to improve the radiographic characteristics of the region of diagnostic importance.
■ Microradiographic and macroradiographic den sity measurement instrumentation: The instrumen tation can identify and measure changes in den sity of historadiographs in an area of 1/x at 1,800X magnification. The clinical macroradiographic unit can identify and measure the density and linear change from clinical radiographs at 10 X magni fication.
D octor Klein is an assistant professor o f pedodontics, In diana U n ive rsity School o f D e n tistry, 1 121 W e st M ic h igan St., Indianapolis, 4 6 2 0 2 . 1. Klein, A . I. The television microscope in d e ntal re search. Dent Prog 2 :2 7 4 Ju ly, 1963. 2. Klein, A . I., and M acPherson, D w ig h t. Television m easurem ent pulse g e n e ra to r-m ixe r. J M ed E lectm c Biol Engng 5 : In press. 3. Klein, A . I.,a n d M acPherson, D w ight. In tra o ra l te le vision m icrom easurem ent in stru m e n ta tio n . J M ed Elec trn c Biol Engng 5 :ln press. 4. H o rw itz, B. A . In tra o ra l television m icrom easure m en t o f ca vity m a rg in d e te rio ra tio n . Thesis, Indiana U n ive rsity School o f D e n tistry, 1966.
T he a u th o r th a nks M r. D w ig h t MacPherson fo r as sisting in th e developm ent and operation o f the television in s tru m e n ta tio n , Doctor Burton H o rw itz fo r pro vid in g the serial television in tra o ra l m icrom easurem ent occlusal hole photographs o f a Class II a llo y restoration, Doctor Jules G eller fo r p ro vid in g the c lin ic a l radiographs, Doc to r A n to n io d e A g u ia r fo r pro vid in g the bone ra d io graphs, and M r. Richard Scott fo r preparing th e illu s tra tiv e m a te ria l. T h is in ve stig a tion was supported in p a rt by USPHS research g ra n t D E -0 1 8 1 3 from th e N a tio n a l In stitu te s o f H e a lth , Bethesda, M d.
5. d e A g u ia r^ A . E. C lin ic a l television rad io g ra p hic eva lu a tion o f spongy bone a rc h ite c tu re in the e d e n tu lous m andible. Thesis, In d ia na U n ive rsity School o f D e n tistry, 1966. 6. Kerkhove, B. C. C lin ic a l and television densitom e tric e va lu a tion o f the in d ire c t p u lp capping technique. Thesis, In diana U n ive rsity School o f D entistry, 1965. 7. Klein, A . I. T elevision m icro d e n sito m e tric h is tio radiographic e va lu a tion o f d e n tin a l sclerosis in p rim a ry teeth. Paper presented a t th e A m e rican A cadem y o f Pedodontics, P hila d e lp h ia , Oct. 11, 1961.
V is ito rs a tte n d in g the a n n ual session in W ash in n ton , D.C., O ctober 2 9 -N o ve m b e r 2, w ho have th e tim e, w ill enjoy a v is it to M o u n t V e r non, home o f George W a sh in g to n, w hich can be reached by ca r or bus via the M o u n t V ernon M e m o ria l H ighw ay
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