A new d e n ta l xe ro ra d io g ra p h ic processor was c lin ic a lly tested. In com parison w ith conventional radiographs, xeroradiographs often showed m ore anatom ic d e ta il o f teeth and bone and re q u ire d a pp ro xim a tely h a lf the exposure tim e. These characteristics, the speed o f operation and the added features fo r convenience, suggest th a t xe ro ra dio grap h y m ay be im p o rta n t to d en tal ra d io g ra p h y in the fu tu re .
C lin ic a l t r ia ls o f in t r a o r a l d e n ta l x e r o r a d io g r a p h y S tu a rt C. W h ite , DDS, PhD B a rto n M . G ra tt, DDS
v
- /a L e r o r a d io g r a p h y has been u sed fo r m e d ic a l d ia g n o s is sin ce th e b e g in n in g o f th is decade fo r m a n y typ es o f ra d io g ra p h ic e x a m in a tio n s , p a rtic u la r ly fo r m a m m o g ra p h y .1 T he m e d ic a l x e ro ra d i o g ra p h ic u n it has also had m a n y d e n ta l a p p lic a tio n s , in c lu d in g c e p h a lo m e tric r a d io g r a p h y ,2' 8 te m p o r o m a n d ib u la r jo in t r a d io g r a p h y ,9 s ia lo g r a p h y ,10-11 a nd p a n o ra m ic ra d io g ra p h y .12 C o n s id e ra tio n has also been g iv e n to a d a p tio n o f th is te c h n o lo g y fo r in tra o ra l use.1317 R e ce n tly, a n e w x e ro ra d io g ra p h ic u n it has been d e s ig n e d s p e c ific a lly fo r d e n ta l in tra o ra l use. T h is d e n ta l im a g in g d e vice uses the same general p r in c i p le s o f x e ro ra d io g ra p h y b u t in co rp o ra te s m o d ific a tio n s in th e d e v e lo p m e n t process th a t re s u lt in im p ro v e d q u a lity o f th e im age. L a b o ra to ry tests o f th is e x p e rim e n ta l in s tru m e n t, u s in g ca d a ve rs, w e re e n c o u ra g in g 18 and le d to p r e lim in a ry c lin ic a l tria ls in tw o u n iv e r s ity d e n ta l schools. T h is re p o rt de scribes the re s u lts o f the p re lim in a ry c lin ic a l tests.
Materials and methods T he fir s t tria ls o f th e d e n ta l x e ro ra d io g ra p h ic u n it (d e ve lo p e d b y X e ro x M e d ic a l System s) w ere c o n d u c te d at th e U n iv e rs ity o f C a lifo rn ia at Los A n ge les a nd th e U n iv e rs ity o f C a lifo rn ia at San F ra n cisco . C o n v e n tio n a l fu ll- m o u th , p e ria p ic a l, and b ite w in g ra d io g ra p h s w e re ta ke n as p a rt o f th e in it ia l e x a m i n a tio n o f p a tie n ts o f th e d e n ta l c lin ic . A fte r c o m p le tio n o f c o n v e n tio n a l ra d io g ra p h s , s im ila r ly p ro jected x e ro ra d io g ra p h s w ere taken o f m a n y o f th e same areas o n c o n s e n tin g p a tie n ts. A to ta l o f 1,200 c lin ic a l x e ro ra d io g ra p h ic im ages w e re exposed d u r in g th re e m o n th s . 8 1 0 ■ J A D A , V o l. 9 9 , N o v e m b e r 1 9 7 9
T he n e w ly d esign ed x e ro ra d io g ra p h ic im age re c e p to r w as h ou sed in a r ig id cassette the size o f a no. 2 p e ria p ic a l film . I t w as p o s itio n e d in tra o r a lly u s in g e ith e r a m o d ifie d re c ta n g u la r c o llim a to r (P re cisio n X-R ay), hem ostats, o r b ite w in g tabs. S im p le m o d ifi c a tio n s o f these in s tru m e n ts w ere re q u ire d as the cassette is a p p ro x im a te ly 2.5 m m th ic k e r th a n a p a cke t o f film . C o n v e n tio n a l d e n ta l ra d io g ra p h ic m a ch in e s w ere used to expose film s and x e ro ra d io g ra p h ic cassettes. T h e m ach in e s w ere operated at 60 to 100 k ilo v o lt peak (k V p ). E xp osu re tim e s w ere ad ju s te d as needed to o b ta in the p ro p e r im age d e n s ity . A fte r e xpo sure, th e x e ro g ra p h ic im a ge rece pto rs w ere processed in th e x e ro ra d io g ra p h ic processor. D e n ta l film s (K o d a k U ltra sp e e d ) w ere processed ac c o rd in g to m a n u fa c tu re rs ’ re c o m m e n d a tio n s in fresh c o n v e n tio n a l p ro ce ssin g s o lu tio n s (K odak) o r in an a u to m a tic p ro cesso r (L itto n ). R e s u lta n t im ages fro m each system (c o n v e n tio n a l ra d io g ra p h s and x e ro ra d io g ra p h s ) w e re th e n a v a ila b le fo r c o m p a ri son. D esig n and o p e ra tio n o f the e x p e rim e n ta l x e ro ra d io g ra p h ic processor have been describ e d in d e ta il b y Je ro m in and o th e rs .19 B rie fly , th e im age rece pto r co nsists o f an a lu m in u m -b a s e d p la te th a t is coated w it h a s e le n iu m a llo y a nd p ro te c te d b y a p la s tic lig h tp r o o f cassette. T h is im a g in g p la te is a c tiv a te d before use b y the a p p lic a tio n o f a surface charge. W h e n th e p la te is exposed in tra o ra lly , the ra d ia tio n p ro p o rtio n a te ly d ischarges th e surface charge o n th e p la te ; th is leaves an e le c tro s ta tic la te n t im age. Be cause the vo lta g e a p p lie d to th e s e le n iu m b a c k in g d u r in g d e v e lo p m e n t o f th e im age (d e v e lo p m e n t e le ctro d e bias) in flu e n c e s the ch a ra c te ris tic s o f th e im age, d iffe re n t e le ctro d e vo ltag es fo r d e v e lo p m e n t
F ig 1
■ X e r o r a d io g r a p h ( A ) c le a r ly s h o w s e n a m e l, d e n t in , a n d p u lp . F e a tu r e s a r e e n h a n c e d b e c a u s e o f e d g e e n
h a n c e m e n t in h e r e n t in x e r o r a d io g r a p h ic p ro c e s s . C o n v e n t io n a l r a d io g r a p h (B ) o f s a m e a r e a is s h o w n .
w ere tested. T h e im a ge is d eve lo pe d b y th e d e p o s i tio n o f ch arge d to n e r p a rticle s on th e la te n t e le c tro s ta tic im age. F in a lly , the im a ge is m e c h a n ic a lly tra n s fe rre d fro m th e s e le n iu m surface b y a clea r a dh esive ta pe a nd is fix e d to an opaque p la s tic sub strate fo r v ie w in g . T h is x e ro ra d io g ra p h ic im a ge m ay be v ie w e d e ith e r in re fle c te d lig h t as a p h o to g ra p h o r b y tra n s m itte d lig h t fro m a v ie w b o x .
Results In th e c lin ic a l tria ls , th e im ages o f the h a rd a nd soft tis s u e s o f th e o r a l c a v it y w e re c o m p a r e d in x e ro ra d io g ra p h ic and c o n v e n tio n a l ra d io g ra p h ic v ie w s o f th e same p atie nts. A d d itio n a lly , va rio u s features w ere e va lu a te d co n ce rn in g the ease o f use o f th e x e ro g ra p h ic system . V a lue s o f ra d ia tio n e x p o sure re q u ire d to p ro d u ce sa tisfa cto ry im ages w ith each system w e re com pared. T h e a m o u n t o f in fo rm a tio n a va ila b le to th e v ie w e r o f d e n ta l x e ro ra d io g ra p h ic im ages d ep en de d o n th e v ie w in g c o n d itio n s used. A lth o u g h x e r o r a d io g ra p h ic im ages are u s e fu l w h e n v ie w e d in ro o m lig h t, th e m a x im u m d ia g n o s tic in fo rm a tio n w as ob ta in e d w h e n th e im ages w ere in te rp re te d on a v ie w b o x w ith m a s k in g o f extraneous lig h t. A c c o rd in g ly , these o bse rva tion s (and illu s tra tio n s ) w ere m ade w it h use o f tra n s m itte d lig h t. T he a m o u n t o f edge e n h a n ce m e n t d epends on the selected se ttin g fo r d e v e lo p m e n t e le ctro d e bias d u rin g d e v e lo p m e n t. W h e n lo w e r vo ltag es o f d e ve lo p m e n t e le ctro d e bias w e re used, th e im ages sh o w e d greater edge e n h a n c e m e n t a nd m ore contrast. W h e n h ig h e r bias v a lu e s w ere used, th e im age sh o w e d less edge e n h a n c e m e n t a n d lo w e r contrast. T EE TH . T e e th are v is u a liz e d w e l l o n x e r o r a d io g ra p h s. E x a m in a tio n o f the enam el cap show s c o n s id e ra b le a n a to m ic d e ta il, e s p e c ia lly o f th e oc c lu s a l a nd m a rg in a l rid ge s and grooves. T h is is u s u
a lly m ore p ro n o u n c e d o n p re m o la rs a nd m o la rs w h e re th e fissures m ay be deep (F ig 1). A reas o f e nam el o v e rla p s h o w th e edges o f b o th ena m e l s u r faces. T h e b o rd e r b etw e e n th e ena m e l a nd d e n tin is seen m ore d is tin c tly on th e x e ro ra d io g ra p h ic im ages. O n th e x e ro ra d io g ra p h s , th e d e n tin e x h ib its a sm o o th a nd stru ctu re le ss surface s im ila r to th a t seen on c o n v e n tio n a l film s . Areas o f c e rv ic a l b u rn o u t are seen less fre q u e n tly on x e ro ra d io g ra p h s th a n on c o n v e n tio n a l film s , as th e w id e r la titu d e o f th e x e ro ra d io g ra p h s a llo w s th e la te ra l surfaces o f te eth in th e c e rv ic a l re g io n to be m o re s h a rp ly d e fin e d (F ig 2). Because o f th e edge e n h a n ce m e n t o f th e x e ro ra d io g ra p h ic process, p u lp cham bers a nd ca n als are m ore c le a rly seen o n x e ro ra d io g ra p h s th a n on c o n v e n tio n a l film s , e s p e c ia lly in th e re g io n s o f the m a x illa ry m o la rs w h e re p u lp a l a n a to m y is o fte n d if f ic u lt to d isce rn . S im ila rly , p u lp stones a nd p u l p a l d y s tro p h ic c a lc ific a tio n s are m ore re a d ily de te c te d o n x e r o r a d io g r a p h s . C e m e n tu m is n o t n o rm a lly seen o n to o th surfaces w it h e ith e r im a g in g system . CARIES. C o m p a ris o n o f th e ra d io g ra p h ic app ea r ance o f in te rp ro x im a l c a rio u s le s io n s sh ow s th a t th e m a rg in s o f these lesio ns are ty p ic a lly m ore s h a rp ly d e fin e d on x e ro ra d io g ra p h s (F ig 3). T h is is tru e fo r le sio n s re s tric te d to th e e na m e l as w e ll as fo r those p e n e tra tin g in to u n d e rly in g d e n tin . G e n e ra lly , the d e p th o f p e n e tra tio n as seen b y each system is c o m parable. E x te n s io n o f gross c a rio u s le s io n s is seen e q u a lly w e ll b y b o th te c h n iq u e s . O c c a s io n a lly , w h e n lo w se ttin g s o f d e v e lo p m e n t e le ctro d e bias are used, a djace nt enam el surfaces w i l l s h o w a d iffu s e ra d io lu c e n t area in th e area o f co n ta ct. T h is app ea r ance is a rtifa c tu a l b u t m a y suggest a c a rio u s le s io n . T h is a rtifa c t m a y be re d u c e d o r e lim in a te d b y in creasing the s e ttin g o f th e d e v e lo p m e n t e le ctro d e bias, b y re d u c in g th e a m o u n t o f ra d ia tio n expo sure, o r b y d o in g b o th . W h it e - G r a t t : C L IN IC A L T R IA L S O F X E R O R A D IO G R A P H Y
■ 811
F ig 2
■ X e r o r a d io g r a p h ( A ) s h o w s w e ll- d e fin e d la t e r a l b o r d e r s o f te e th ju s t a b o v e a lv e o la r c re s ts b e c a u s e o f
w id e r la t it u d e a v a ila b le i n x e r o g r a p h ic p r o c e s s . C o n v e n t io n a l im a g e ( B ) s h o w s a r e a s o f “ c e r v ic a l b u r n o u t . ”
F ig 3
■ X e r o r a d io g r a p h ( A ) is m a g n if ie d v ie w o f p o r t io n o f b it e w in g p r o je c t io n s h o w in g m u lt ip le c a r io u s te e th .
C o n v e n t io n a l r a d io g r a p h (B ) s h o w s c o m p a r a b le a r e a .
BONE. T h e la m in a d u ra , in c o n ju n c tio n w ith the a l v e o la r crest, is seen b e tte r on x e ro ra d io g ra p h ic im ages. T h is is m o st u s e fu l w h e n the a p ic a l p o rtio n s o f te e th are e x a m in e d fo r p e ria p ic a l disease o r w h e n th e p o s itio n o f ro o t apexes is d e te rm in e d . In d iv id u a l b o n y tra b e cu la e are also seen m ore s h a rp ly on the x e ro ra d io g ra p h ic im ages. T h is is e s p e c ia lly e v id e n t in in te r ra d ic u la r areas b u t is also n o tice a b le in bone s u p e rim p o s e d o ve r teeth. V a ria tio n s in d e n s ity and s tru c tu re o f bone tra b e cu la tio n s m ay be e a s ily ob served. T h is is im p o rta n t in e v a lu a tio n o f p e ria p ic a l bone fo r e vid e n ce o f ly s is fro m p u lp a l disease. Areas o f dense s c le ro tic bone are also re a d ily observed; o fte n m o re d e ta il is n o tic e d th a n on c o n v e n tio n a l film s . T h e s tru c tu re o f the in te rra d ic u la r a lv e o la r crest m a y be seen w ith co nside rab le c la r ity a nd m a y a id in e a rly id e n tific a tio n o f p e rio d o n ta l disease (F ig 4). PERIODONTAL LIG AM EN T SPACE. T h e p e rio d o n ta l lig a m e n t space is s h a rp ly d e fin e d on x e ro ra d io g ra p h ic im ages as the edge e ffe ct p ro v id e s sharp c o n tra s t w it h th e a djace nt dense to o th a nd la m in a 8 1 2 ■ J A D A , V o l. 99 , N o v e m b e r 1 9 7 9
d ura. T h is is p a r tic u la rly h e lp fu l in id e n tify in g in d iv id u a l roots th a t are o fte n o v e rla p p e d in m u l tiro o te d teeth. A ls o , th e apex o f th e ro o t is m ore p re c is e ly d e fin e d and m o re e a s ily e x a m in e d because o f a m o re s h a rp ly id e n t if ie d p e rio d o n ta l lig a m e n t space and la m in a dura. SOFT TISSUES. G in g iv a l tissues are m ore re a d ily seen on x e ro ra d io g ra p h ic im ages. T h is is e v id e n t b o th o n b ite w in g a nd p e ria p ic a l p ro je c tio n s . T h is c h a ra c te ris tic is also tru e fo r o th e r soft tissu e s tru c tu re s su ch as the tip o f th e nose, the lip s , and the cheeks (F ig 5). In a d d itio n , c a lc ific a tio n s o f so ft tis sue m ay o c c a s io n a lly be seen th a t are n o t e v id e n t on c o n v e n tio n a l ra d io g ra p h s. CALCULUS. C o m p a riso n o f x e ro ra d io g ra p h ic im ages w ith c o n v e n tio n a l ra d io g ra p h s sh ow s a d e c id e d d if ference in the degree to w h ic h d ep osits o f c a lc u lu s m ay be detected. X e ro ra d io g ra p h ic im ages s h o w b o th s u p ra g in g iv a l a n d s u b g in g iv a l c a lc u lu s in m u c h greater d e ta il (F ig 6).
F ig 4
■ X e r o r a d io g r a p h ( A ) c le a r ly s h o w s a lv e o la r c re s ts a n d tr a b e c u la r b o n e . C o n v e n t io n a l r a d io g r a p h (B )
s h o w s s a m e a re a .
F ig 5
■ X e r o r a d io g r a p h ( A ) s h o w s s o f t tis s u e o f t ip o f n o s e p r o je c te d o v e r r o o t s o f in c is o r s . C o n
v e n tio n a l r a d io g r a p h (B ) s h o w s s a m e a re a .
RESTORATIVE M A TER IA LS . C o m m o n ly used re s to ra tiv e m a te ria ls sh o w the same re la tiv e ra d io d e n s itie s w it h b o th system s. A m a lg a m and g o ld resto ra tio n s are e n tire ly ra d io p a q u e , w hereas p o rc e la in and p la s tic re s to ra tio n s are m ore ra d io lu c e n t. Base m a te ria ls are re a d ily d is tin g u is h e d fro m a m a lg a m or g o ld . W ith d e v e lo p m e n t e le ctro d e bias se tting s, th e great d iffe re n c e in ra d io g ra p h ic d e n sitie s o f a m a l gam a nd d e n tin m ay re s u lt in excessive edge en h a n ce m e n t in th e im age o f th is ju n c tio n . A s a re s u lt, p o rtio n s o f th e m a rg in o f the d e n tin a djace nt to m e ta llic re s to ra tio n s m a y s h o w a p e rip h e ra l ra d io lu c e n t zone. Care m u s t be ta ken n o t to confuse th is area w ith re c u rre n t caries th a t i t m a y resem ble. T h is a rtifa c t is d im in is h e d w h e n h ig h e r vo ltag es o f de v e lo p m e n t e le c tro d e b ias o r lo w e r e xp o su re s o f ra d ia tio n are used. R e e x a m in a tio n o f th e same teeth w ith h ig h e r values o f d e v e lo p m e n t e le ctro d e bias e ith e r e lim in a te s th is p ro b le m o r reduces i t to w it h in a cceptable lim its (Fig 7).
ARTIFACTS. In g eneral, th e in c id e n c e o f a rtifa c ts w as h ig h e r th a n on c o n v e n tio n a l film . A rtifa c ts u s u a lly appeared as s m a ll w h ite o r b la c k dots a lth o u g h o ccasion al lin e s w ere observed. In a ll cases, th e a rtifa c tu a l n atu re w as c le a rly e v id e n t a nd th e y w e re n o t c o n fu s e d w it h a n a to m ic s tru c tu re s . I t w as a lso n o tic e d th a t c e n tra l areas o f large m e ta llic re s to ra tio n s w o u ld o c c a s io n a lly s h o w d a rk e n in g because o f d e p o s itio n o f to n e r. P o te n tia l d iffic u ltie s re s u lt in g fro m lo w s e ttin g s o f d e v e lo p m e n t e le ctro d e bias w ere d escribed. A s w it h m o st ra d io g ra p h ic a rtifa c ts , th e greatest p ro b le m w as the p o s s ib ility o f o b s c u r in g im p o rta n t in fo rm a tio n . DOSIMETRY. E v a lu a tio n o f the param eters o f e x p o sure used in th e c lin ic and la b o ra to ry in d ic a te s th a t c o n v e n tio n a l d e n ta l ra d io g ra p h ic m a c h in e s o p e ra t in g in th e u s u a l (60 to 100) k V p range are a p p ro p r i ate fo r e x p o s in g x e ro ra d io g ra p h s . In o u r e xp e rie n ce , th e exposure tim e m a y be re d u c e d b y a fa c to r o f 2 to W h it e - G r a t t : C L I N I C A L T R IA L S O F X E R O R A D IO G R A P H Y
»813
F ig 6
■ X e r o r a d io g r a p h ( A ) d e m o n s tr a te s m o r e e x te n s iv e d e p o s itio n o f c a lc u lu s t h a n is e v id e n t o n c o n v e n t io n a l
r a d io g r a p h s (B ) o f s a m e a re a .
F ig 7
■ X e r o r a d io g r a p h ( A ) w a s p r o c e s s e d w i t h lo w d e v e l
o p m e n t e le c tr o d e b ia s a n d s h o w s r a d io lu c e n t a r e a s , a d ja c e n t t o a m a lg a m r e s to r a tio n s , t h a t a r e n o t s u b s ta n tia te d o n c o n v e n t io n a l r a d io g r a p h ( B ) o f s a m e a r e a . I n c r e a s in g d e v e l o p m e n t e le c t r o d e b ia s r e d u c e s im a g e c o n t r a s t a n d r e m o v e s r a d io lu c e n t a r e a s ( Q .
3 fo r x e ro ra d io g ra p h y co m p ared w ith th a t used fo r c o n v e n tio n a l (D-speed) film .
Operation of dental xeroradiographic processor Several in h e re n t features in the o p e ra tio n o f th e d e n ta l x e ro ra d io g ra p h ic processor are d iffe re n t fro m c o n v e n tio n a l ra d io g ra p h ic p rocedures. ROOM LIG H T PROCESSING. A s th e x e ro ra d io g ra p h ic cassettes m a y be processed in ro o m lig h t, the p ro 8 1 4 ■ J A D A , V o l. 9 9 , N o v e m b e r 1 9 7 9
cessor m ay be lo ca te d near th e ra d io g ra p h ic m a c h in e fo r ra p id access b y th e o pe ra to r. T h is can p o te n tia lly e lim in a te th e need fo r a d a rk ro o m . FAST, DRY IMAGES. T he p ro cessin g c y c le , fro m tim e o f in s e rtio n o f th e cassette in to th e p rocessor u n t il a d ry im age is a v a ila b le fo r v ie w in g , is 20 seconds. T h is gives th e o p e ra to r an o p p o r tu n ity to e xam in e th e re s u lta n t im age w ith o u t a p p re c ia b le d e la y and to in te rp re t th e x e ro ra d io g ra p h s im m e d ia te ly to de te rm in e i f a d d itio n a l p ro je c tio n s o r th e re ta k in g o f an im age is needed.
R O O M L IG H T V IE W IN G . T h e x e r o r a d io g r a p h ic im a ge appears as a p h o to g ra p h th a t m a y be v ie w e d at c h a irs id e i n ro o m lig h t, a nd th e re b y is easier to v ie w d u r in g c lin ic a l a c tiv ity . W e have n o tic e d th a t p a tie n ts a re o fte n in t e r e s te d i n v ie w in g th e x e ro ra d io g ra p h ic im ages a nd ask q u e stio n s a b o u t tre a tm e n t. T h e re b y, an e d u c a tio n a l o p p o r tu n ity fo r th e p a tie n t is p ro v id e d . H o w e v e r, th e m a x im a l a m o u n t o f in fo r m a tio n fro m th e im ages is a ch ie ve d w h e n th e y are v ie w e d w it h tra n s m itte d lig h t. R IG ID CASSETTES. In o u r e xpe rie nce , use o f r ig id cassettes does n o t cause u n d u e d iffic u ltie s fo r p a tie n ts o r operators. T h e cassettes w e re c a re fu lly p o s itio n e d w e ll in to th e o ra l c a v ity a nd a w a y fro m th e p a la ta l o r lin g u a l surfaces o f te e th in accordance w it h th e p rin c ip le s o f th e p a ra lle lin g te c h n iq u e . W h e n i t is necessary to ta ke im ages u s in g th e b is e c t in g a n g le te c h n iq u e , th e cassette m a y be s u p p o rte d in tra o r a lly w it h th e fin g e rs . REUSABLE CASSETTES. Because th e cassettes are re usable, i t w as necessary to p re v e n t m ic ro b io lo g ic a l c o n ta m in a tio n . In o u r c lin ic a l tria ls , th e cassettes w e re in d iv id u a lly w ra p p e d in s te rile , d isp osa ble , p la s tic bags befo re b e in g p la ce d in th e m o u th . T h is p ro c e d u re also p ro te cts th e im a g e re c e p to r fro m s a liv a ry c o n ta m in a tio n th a t c o u ld cause an im age a rtifa c t. SIZE OF IM AGE. D u rin g o u r tr ia l, o n ly im a g e rece p to rs th e size o f no. 2 p e ria p ic a l f i l m w e re a va ila b le a lth o u g h th e x e ro ra d io g ra p h ic pro cesso r is b e in g d e s ig n e d to p ro v id e cassettes th e size o f b o th n o. 1 a n d n o. 2 p e ria p ic a l film . T h e size o f th e re s u lta n t x e ro ra d io g ra p h ic im a g e is a p p ro x im a te ly 3 m m s m a lle r in each d im e n s io n th a n th e c o rre s p o n d in g p e ria p ic a l film . A lth o u g h n o. 1- a n d no. 2-size f ilm a c c o u n t fo r th e m a jo rity o f ra d io g ra p h s e xposed in th e g en eral d e n ta l p ra c tic e , c o n v e n tio n a l f i l m and p ro ce ssin g te ch n iq u e s m u s t be m a in ta in e d i f o th e r sizes o f f ilm are used.
Discussion D e v e lo p m e n t o f a d e n ta l x e ro ra d io g ra p h ic p ro cessor o ffe rs th e p ro sp e ct o f increa se d d ia g n o s tic c a p a b ility fo r d e n tists. T h is n e w system is d e sig n e d to w o r k w it h c o n v e n tio n a l ra d io g ra p h ic m ach in e s c u r r e n tly u sed i n d e n ta l o ffic e s . T h e x e ro ra d io g ra p h ic process is based o n w e ll-re s e a rc h e d im a g in g p rin c ip le s th a t have been w id e ly used in m e d i ca l ra d io g ra p h y . I t s h o u ld be n o tic e d , h o w e v e r, th a t th e d e n ta l u n it d e scrib e d in th is re p o rt is d is tin c t fro m th e system (X e ro x 125 M e d ic a l System ) in w id e s p re a d use sin ce 1970. A lth o u g h b o th system s d e m o n stra te th e p ro p e rty o f edge e nh an cem en t, th e d e n ta l system has a d iffe re n t system o f d e v e lo p m e n t
a n d p ro v id e s m u c h greater im a ge re s o lu tio n .18 D e n tis ts s h o u ld c a re fu lly c o n s id e r th e p o te n tia l im p a c t o f th is process o n th e ir p ra c tic e befo re d e c id in g to r e g u la rly use th is in s tru m e n t. O u r a n a ly s is is c o n s id e re d in th re e areas: Does use o f th e d e n ta l x e ro ra d io g ra p h ic system m ake a v a ila b le n e w d ia g n o s tic in fo rm a tio n ? Is th e re a n e w h aza rd associated w it h th e process? Is th is system p ra c tic a l in th e d e n ta l o ffice ? DIAGNOSTIC YIELD. T h e p rim a r y d ia g n o s tic v a lu e o f d e n ta l x e ro ra d io g ra p h y is its c a p a b ility o f p ro d u c in g im ages s u p e rio r in d ia g n o s tic q u a lity . In o u r c lin ic a l tria ls , th e d e n ta l x e ro ra d io g ra p h ic im ages c o u ld a llo w v is u a liz a tio n o f o ra l tissues w it h greater c la r ity a n d in m o re d e ta il th a n w as o b ta in e d w h e n c o n v e n tio n a l ra d io g ra p h y w as used. T h is re s u lts p r im a r ily fro m th e p ro p e rty o f edge e nh a n ce m e n t in h e re n t i n th e x e ro ra d io g ra p h ic process w h ic h ac centuates s m a ll d iffe re n ce s in d e n s ity o f tw o adja c e n t s tru c tu re s . S m a ll s tru c tu re s th a t d iffe r in d e n s ity fr o m th e im m e d ia te e n v iro n m e n t, s u c h as p e rio d o n ta l lig a m e n t, p u lp canals near th e apex o f th e ro o t, o r t h in p la te s o f tra b e c u la r bone, are m o re e a s ily seen o n x e ro ra d io g ra p h ic im ages. C ariou s le sion s w e re seen a t least as w e ll o n x e ro ra d io g ra p h ic im a g e s as o n c o n v e n tio n a l f i lm . In e x a m in in g p e rio d o n ta l disease, a lv e o la r bone m a y be s tu d ie d w it h gre ate r c o n fid e n c e th a n is c u rre n tly th e case w it h c o n v e n tio n a l film . O u r e x p e rie n c e sh ow s th a t th is n e w x e ro ra d io g ra p h ic process can d em on strate m o re s u b tle p a th o lo g ic changes in th e o ra l tissues th a n c o n v e n tio n a l ra d io g ra p h ic f ilm . I t m u s t be re c o g n iz e d , h o w e v e r, th a t o u r o bse rva tion s re p re se n t c lin ic a l im p re s s io n s d e r iv e d fr o m s id e -b y -s id e c o m p a ris o n s o f x e ro ra d io g ra p h s a nd c o n v e n tio n a l ra d io g ra p h s . I t is im p o rta n t th a t c o n tro lle d q u a n tita tiv e e v a lu a tio n s be m ade o f th e in c id e n c e o f d ete c tio n o f disease b y each system to s u p p le m e n t these o b se rva tion s. T o e va lu a te d ia g n o s tic u sefu lne ss o f a n e w p ro cess, th e p o s s ib ility m u s t be c o n s id e re d th a t use o f th e n e w system w i l l re s u lt in e rro r— e ith e r b y th e v ie w e r m is s in g p a th o lo g ic c o n d itio n s th a t a c tu a lly e x is t o r b y m is in te rp re tin g a rtifa c ts th a t resem ble n o n e x is te n t p a th o lo g ic c o n d itio n s . T h e s e p o s s ib ilitie s have been e x a m in e d in o u r c lin ic a l tria ls b y c o m p a ris o n o f x e ro ra d io g ra p h ic im ages w it h c o n v e n tio n a l ra d io g ra p h s o f th e same te eth. In o u r e x p e rie n c e , c a rio u s le s io n s a nd osseous changes w e re seen o n th e x e ro ra d io g ra p h ic im ages w h e n e ver th e y w e re seen o n co m p a ra b le c o n v e n tio n a l film . O c c a s io n a lly , h o w e v e r, a rtifa c ts w e re seen th a t o bscu re d d e ta il o f th e im age. C o n s id e rin g th a t th e s tu d ie d in s tru m e n t w as an e x p e rim e n ta l m o d e l o n its f ir s t c lin ic a l tria ls , th e in c id e n c e o f su ch a rtifa c ts w as lo w . O f greater c o n c e rn is th e o c c a s io n a l a rtifa c tu a l appearance o f a ra d io lu c e n t m a rg in a ro u n d a W h i t e - G r a t t : C L IN IC A L T R IA L S O F X E R O R A D IO G R A P H Y
815
p o r tio n o f an a m a lg a m re s to ra tio n o r th e d iffu s e ra d io lu c e n t area o n a d ja ce n t surfaces o f e n a m e l th a t suggest re c u rre n t decay. T h is c o n d itio n is m o st p re v a le n t w h e n lo w va lu e s o f d e v e lo p m e n t e le ctro d e b ia s are used to a chieve im ages w it h h ig h co ntrast. T h is p ro b le m w as re d u c e d b y in c re a s in g th e d e v e l o p m e n t e le ctro d e vo lta g e o r b y decrea sing th e ra d ia tio n e xposure. O u r e x p e rie n ce suggests th a t use o f d u a l d e v e lo p m e n t e le ctro d e b ias s e ttin g s o n th e pro cesso r m a y p ro v id e th e best re s u lts fo r d iffe re n t p ro je c tio n s o r c lin ic a l circu m sta n ce s. M o re research is re q u ire d to d e te rm in e th e o p tim a l c o m b in a tio n o f c lin ic a l, e le c tric a l, a n d ra d ia tio n e xpo sure fa cto rs re q u ire d to a chieve th e m o s t d ia g n o s tic a lly u s e fu l im ages.
Conclusions C lin ic a l tria ls o f th e e x p e rim e n ta l d e n ta l x e ro ra d io g ra p h ic syste m have c le a rly in d ic a te d th a t th e i n s tru m e n t w i l l be v a lu a b le to d e n tis try . A lth o u g h th e re is m u c h to be le a rn e d , th e c a p a c ity o f th e sys te m to p ro d u c e im ages o f h ig h d ia g n o s tic q u a lity , th e ease o f o p e ra tio n , a n d th e re d u c e d e xpo sure to p a tie n ts re p re s e n t p o s itiv e c o n trib u tio n s to th e p ra c tic e o f d e n ta l ra d io g ra p h y .
T h e a u t h o r s t h a n k M r s . C y n t h ia C a r b e r r y , t h e W o r d P r o c e s s in g C e n te r u n d e r th e d ir e c tio n o f M r s . R h o d a F r e e m a n , a n d th e a u d io v is u a l d e p a rt m e n t f o r h e lp i n p r e p a r in g t h e m a n u s c r ip t . D r . W h i t e is a s s o c ia t e p r o f e s s o r a n d c h a ir m a n , s e c t io n o f o r a l r a d io lo g y , S c h o o l o f D e n t is t r y , U n iv e r s it y o f C a lif o r n ia L o s A n g e le s , T h e C e n te r f o r
HAZARD. T h e p rim a r y b io lo g ic a l h a za rd associated w it h d e n ta l d ia g n o s tic r a d io g ra p h y (o th e r th a n in te rp re ta tio n a l e rro r) is th e p o s s ib ility o f so m a tic r a d ia tio n in ju r y . T h e e x te n t o f th is ris k , i f a ny, is u n k n o w n b u t i t is m o s t p ro b a b ly p ro p o rtio n a l to th e ext e n t o f e x p o s u r e . O u r e x p e r ie n c e w i t h th e x e ro ra d io g ra p h ic system in d ic a te d th a t th e e x p o sure to p a tie n ts m a y be re d u c e d b y a fa c to r o f 2 to 3 fro m c o n v e n tio n a l ra d io g ra p h y . It s h o u ld be fu rth e r n o tic e d th a t, i f s u b o p tim a l f ilm p ro ce ssin g te c h n iq u e s a re u s e d , th e d o s e a d v a n ta g e o f th e x e r o r a d io g r a p h ic s y s te m w i l l t h e n b e c o r r e s p o n d in g ly m o re fa vorab le. T h is re d u c tio n in dose w i l l b e n e fit b o th p a tie n ts a n d d e n ta l p e rs o n n e l e x posed to scatter ra d ia tio n .
H e a lt h S c ie n c e s , L o s A n g e le s 9 0 0 2 4 . D r . G r a t t is a s s is t a n t p r o f e s s o r , d e p a r t m e n t o f o r a l r a d io lo g y , s e c tio n o f g e n e r a l d e n t is t r y , S c h o o l o f D e n t is t r y , U n iv e r s it y o f C a lif o r n ia L o s A n g e le s . A d d r e s s r e q u e s ts f o r r e p r in t s to D r . W h ite . 1 . W o lf e , J .N . X e r o r a d io g r a p h y o f th e b r e a s t. S p r in g f ie ld ,
111, C
h a r le s C
Thom as, 1972. 2 . B in n ie , W . H . , a n d o th e r s . A p p lic a t io n o f x e r o r a d io g r a p h y i n
den
t is tr y . J D e n t 3 ( 3 ) :9 9 - 1 0 4 ,1 9 7 5 . 3 . S c h r iv e r , W . R . ; S w in t a k , E .F .; a n d D a r la k , J .D . X e r o c e p h a lo g r a p h y . O r a l S u rg 4 0 (6 ):7 0 5 -7 0 8 , 1 9 7 5 . 4 . L o p e x , J ., J r . X e r o r a d io g r a p h y
in
d e n tis tr y . J A D A
9 2 (1 ):1 0 6 -1 1 0 ,
1976. 5 . T ip n is , A . K . X e r o r a d io g r a p h y f o r la t e r a l s k u ll r a d io g r a p h s . B r J O r th o d 1 (5 ):1 8 7 -1 8 9 ,1 9 7 4 . 6 . D a v is , R ., a n d o th e r s . T h e r o le o f x e r o r a d io g r a p h y i n c e p h a lo m e tr ic r a d io lo g y . J D e n t 5 ( l) : 3 2 - 3 8 , 1 9 7 7 . 7 . H u r s t, R ., a n d o th e r s . L a n d m a r k id e n t if ic a t io n a c c u ra c y in x e r o r a d io g r a p h ic c e p h a lo m e tr y . A m J Q r t h o d 7 3 ( 5 ) : 5 6 8 - 5 7 4 , 1 9 7 8 . 8 . J o h n s o n , N . A . X e r o r a d io g r a p h y f o r c e p h a lo m e tr ic a n a ly s is . A m J O r th o d 6 9 (5 ):5 2 4 -5 2 6 ,1 9 7 6 .
P R A C T IC A L IT Y . O u r c l i n i c a l t e s t i n g o f th e x e ro ra d io g ra p h ic p rocessor w as c o n d u c te d w it h an e x p e rim e n ta l m o d e l in an in s titu tio n a l e n v iro n m e n t. N eve rthe less, in o u r e xpe rie nce , th e ease o f o p e ra tio n , th e r a p id a v a ila b ility o f th e im ages, a n d th e ease o f in t e r p r e t a t io n a v a ila b le w i t h th e x e ro ra d io g ra p h ic system are d e sira b le features th a t w o u ld assist in tre a tm e n t. R a p id d e liv e ry o f im ages m a y also h e lp th e o p e ra to r as i t is easy to ch e ck w h e n a n a to m ic re g io n s are s a tis fa c to rily im a g e d . T h e o p p o r tu n ity to im m e d ia te ly expose a n o th e r xe ro ra d io g ra p h is p ro v id e d . Use o f r ig id cassettes w as p re v i o u s l y fo u n d c o m p a tib le w i t h in t r a o r a l r a d io g ra p h y .20 T h e system is lim ite d in th a t im ages are re s tric te d to th e size o f no. 1 a nd n o. 2 film . I f o th e r sizes o f f ilm are d esire d , a fa c ility fo r c o n v e n tio n a l p ro ce ssin g m u s t be m a in ta in e d .
9 . X e r o x C o r p o r a tio n . X e r o r a d io g r a p h y f o r t e m p o r o m a n d ib u la r jo in t . M e d ic a l A p p lic a t io n B u ll 1 1 5 ,1 9 7 3 . 1 0 . F e rg u s o n , M .M ., a n d
o th e rs . A p p lic a tio n
o f x e r o r a d io g r a p h y in
s ia lo g r a p h y . I n t J O r a l S u r g 5 :1 7 6 - 1 7 9 ,1 9 7 6 . 1 1 . G la s s m a n , L . M . ; O ’H a r a , A . E . ; a n d C r e g a r , D . X e r o s ia lo g r a p h y . A r c h O to la r y n g o l 1 0 0 ( 5 ) :3 4 1 - 3 4 3 ,1 9 7 4 . 1 2 . S n y d e r, B ., a n d
o th e rs . T h e
a d v a n ta g e s o f x e r o r a d io g r a p h y f o r
p a n o r a m ic e x a m in a t io n o f th e ja w s a n d te e th . J P e r io d o n t o l 4 8 ( 8 ) :4 6 7 - 4 7 2 , 1977. 1 3 . P o r g o r z e ls k a - S tr o n c z a k , B . T r ia ls o f e m p lo y in g r a d io x e r o g r a p h y in d e n t is t r y . C z a s S to m a t o l ll( 1 2 ) : 8 7 7 - 8 7 9 , 1 9 5 8 . 1 4 . L a p in s k a s , V . A . , a n d ( x e r o r a d io g r a p h y ) a n d
L a p in s k e n e , A . V .
p ro s p e c ts o f its
u s e in
E le c tr o r o e n tg e n o g r a p h y d e n t is t r y . S to m a to lo g ia
(M o s k ) 4 7 {4 ):3 5 -3 8 ,1 9 6 8 . 1 5 . R a w ls , H .R ., a n d
O w e n , W .D . T h e
d e n t a l p r o g n o s is f o r x e r o r a
d io g r a p h y . O r a l S u r g 3 3 :4 7 6 - 4 8 0 ,1 9 7 2 . 1 6 . G r a tt, B .M .; S ic k le s , E .A .; a n d P a r k s , C .R . X e r o r a d io g r a p h y o f d e n ta l s tr u c tu r e s . P r e lim in a r y in v e s tig a tio n s . O r a l S u r g 4 4 ( 1 ) : 1 4 8 - 1 5 2 , 1 9 7 7 . 1 7 . G r a tt, B .M .; S ic k le s , E .A .; a n d P a r k s , C .R . X e r o r a d io g r a p h y o f d e n ta l s tr u c tu r e s . Im a g e a n a ly s is . O r a l S u r g 4 6 ( 1 ) : 1 5 6 - 1 6 5 , 1 9 7 8 . 1 8 . W h it e , S .C .; S t a f f o r d , M . L . ; a n d B e e n in g a , L . R . I n t r a o r a l x e r o r a d io g r a p h y . O r a l S u r g 4 6 :8 6 2 - 8 7 0 ,1 9 7 8 . 1 9 . J e r o m in , L . , a n d o th e r s . X e r o r a d io g r a p h y f o r in t r a - o r a l d e n t a l r a d io lo g y : a p r o c e s s d e s c r ip tio n . O r a l S u r g , t o b e p u b lis h e d . 2 0 . G r a tt, B .M .; S ic k le s , E .A .; a n d P a r k s , C .R . U s e o f in t r a o r a l c a s s e tte s f o r d e n ta l x e r o r a d io g r a p h y . O r a l S u r g 4 6 : 7 1 7 - 7 2 0 ,1 9 7 8 .
8 1 6 ■ J A D A , V o l. 9 9 , N o v e m b e r 1 9 7 9
C lin ic a l t r ia ls o f in t r a o r a l d e n ta l x e r o r a d io g r a p h y S tu a rt C. W h ite , DDS, PhD B a rto n M . G ra tt, DDS
v
- /a L e r o r a d io g r a p h y has been u sed fo r m e d ic a l d ia g n o s is sin ce th e b e g in n in g o f th is decade fo r m a n y typ es o f ra d io g ra p h ic e x a m in a tio n s , p a rtic u la r ly fo r m a m m o g ra p h y .1 T he m e d ic a l x e ro ra d i o g ra p h ic u n it has also had m a n y d e n ta l a p p lic a tio n s , in c lu d in g c e p h a lo m e tric r a d io g r a p h y ,2' 8 te m p o r o m a n d ib u la r jo in t r a d io g r a p h y ,9 s ia lo g r a p h y ,10-11 a nd p a n o ra m ic ra d io g ra p h y .12 C o n s id e ra tio n has also been g iv e n to a d a p tio n o f th is te c h n o lo g y fo r in tra o ra l use.1317 R e ce n tly, a n e w x e ro ra d io g ra p h ic u n it has been d e s ig n e d s p e c ific a lly fo r d e n ta l in tra o ra l use. T h is d e n ta l im a g in g d e vice uses the same general p r in c i p le s o f x e ro ra d io g ra p h y b u t in co rp o ra te s m o d ific a tio n s in th e d e v e lo p m e n t process th a t re s u lt in im p ro v e d q u a lity o f th e im age. L a b o ra to ry tests o f th is e x p e rim e n ta l in s tru m e n t, u s in g ca d a ve rs, w e re e n c o u ra g in g 18 and le d to p r e lim in a ry c lin ic a l tria ls in tw o u n iv e r s ity d e n ta l schools. T h is re p o rt de scribes the re s u lts o f the p re lim in a ry c lin ic a l tests.
Materials and methods T he fir s t tria ls o f th e d e n ta l x e ro ra d io g ra p h ic u n it (d e ve lo p e d b y X e ro x M e d ic a l System s) w ere c o n d u c te d at th e U n iv e rs ity o f C a lifo rn ia at Los A n ge les a nd th e U n iv e rs ity o f C a lifo rn ia at San F ra n cisco . C o n v e n tio n a l fu ll- m o u th , p e ria p ic a l, and b ite w in g ra d io g ra p h s w e re ta ke n as p a rt o f th e in it ia l e x a m i n a tio n o f p a tie n ts o f th e d e n ta l c lin ic . A fte r c o m p le tio n o f c o n v e n tio n a l ra d io g ra p h s , s im ila r ly p ro jected x e ro ra d io g ra p h s w ere taken o f m a n y o f th e same areas o n c o n s e n tin g p a tie n ts. A to ta l o f 1,200 c lin ic a l x e ro ra d io g ra p h ic im ages w e re exposed d u r in g th re e m o n th s . 8 1 0 ■ J A D A , V o l. 9 9 , N o v e m b e r 1 9 7 9
T he n e w ly d esign ed x e ro ra d io g ra p h ic im age re c e p to r w as h ou sed in a r ig id cassette the size o f a no. 2 p e ria p ic a l film . I t w as p o s itio n e d in tra o r a lly u s in g e ith e r a m o d ifie d re c ta n g u la r c o llim a to r (P re cisio n X-R ay), hem ostats, o r b ite w in g tabs. S im p le m o d ifi c a tio n s o f these in s tru m e n ts w ere re q u ire d as the cassette is a p p ro x im a te ly 2.5 m m th ic k e r th a n a p a cke t o f film . C o n v e n tio n a l d e n ta l ra d io g ra p h ic m a ch in e s w ere used to expose film s and x e ro ra d io g ra p h ic cassettes. T h e m ach in e s w ere operated at 60 to 100 k ilo v o lt peak (k V p ). E xp osu re tim e s w ere ad ju s te d as needed to o b ta in the p ro p e r im age d e n s ity . A fte r e xpo sure, th e x e ro g ra p h ic im a ge rece pto rs w ere processed in th e x e ro ra d io g ra p h ic processor. D e n ta l film s (K o d a k U ltra sp e e d ) w ere processed ac c o rd in g to m a n u fa c tu re rs ’ re c o m m e n d a tio n s in fresh c o n v e n tio n a l p ro ce ssin g s o lu tio n s (K odak) o r in an a u to m a tic p ro cesso r (L itto n ). R e s u lta n t im ages fro m each system (c o n v e n tio n a l ra d io g ra p h s and x e ro ra d io g ra p h s ) w e re th e n a v a ila b le fo r c o m p a ri son. D esig n and o p e ra tio n o f the e x p e rim e n ta l x e ro ra d io g ra p h ic processor have been describ e d in d e ta il b y Je ro m in and o th e rs .19 B rie fly , th e im age rece pto r co nsists o f an a lu m in u m -b a s e d p la te th a t is coated w it h a s e le n iu m a llo y a nd p ro te c te d b y a p la s tic lig h tp r o o f cassette. T h is im a g in g p la te is a c tiv a te d before use b y the a p p lic a tio n o f a surface charge. W h e n th e p la te is exposed in tra o ra lly , the ra d ia tio n p ro p o rtio n a te ly d ischarges th e surface charge o n th e p la te ; th is leaves an e le c tro s ta tic la te n t im age. Be cause the vo lta g e a p p lie d to th e s e le n iu m b a c k in g d u r in g d e v e lo p m e n t o f th e im age (d e v e lo p m e n t e le ctro d e bias) in flu e n c e s the ch a ra c te ris tic s o f th e im age, d iffe re n t e le ctro d e vo ltag es fo r d e v e lo p m e n t
F ig 1
■ X e r o r a d io g r a p h ( A ) c le a r ly s h o w s e n a m e l, d e n t in , a n d p u lp . F e a tu r e s a r e e n h a n c e d b e c a u s e o f e d g e e n
h a n c e m e n t in h e r e n t in x e r o r a d io g r a p h ic p ro c e s s . C o n v e n t io n a l r a d io g r a p h (B ) o f s a m e a r e a is s h o w n .
w ere tested. T h e im a ge is d eve lo pe d b y th e d e p o s i tio n o f ch arge d to n e r p a rticle s on th e la te n t e le c tro s ta tic im age. F in a lly , the im a ge is m e c h a n ic a lly tra n s fe rre d fro m th e s e le n iu m surface b y a clea r a dh esive ta pe a nd is fix e d to an opaque p la s tic sub strate fo r v ie w in g . T h is x e ro ra d io g ra p h ic im a ge m ay be v ie w e d e ith e r in re fle c te d lig h t as a p h o to g ra p h o r b y tra n s m itte d lig h t fro m a v ie w b o x .
Results In th e c lin ic a l tria ls , th e im ages o f the h a rd a nd soft tis s u e s o f th e o r a l c a v it y w e re c o m p a r e d in x e ro ra d io g ra p h ic and c o n v e n tio n a l ra d io g ra p h ic v ie w s o f th e same p atie nts. A d d itio n a lly , va rio u s features w ere e va lu a te d co n ce rn in g the ease o f use o f th e x e ro g ra p h ic system . V a lue s o f ra d ia tio n e x p o sure re q u ire d to p ro d u ce sa tisfa cto ry im ages w ith each system w e re com pared. T h e a m o u n t o f in fo rm a tio n a va ila b le to th e v ie w e r o f d e n ta l x e ro ra d io g ra p h ic im ages d ep en de d o n th e v ie w in g c o n d itio n s used. A lth o u g h x e r o r a d io g ra p h ic im ages are u s e fu l w h e n v ie w e d in ro o m lig h t, th e m a x im u m d ia g n o s tic in fo rm a tio n w as ob ta in e d w h e n th e im ages w ere in te rp re te d on a v ie w b o x w ith m a s k in g o f extraneous lig h t. A c c o rd in g ly , these o bse rva tion s (and illu s tra tio n s ) w ere m ade w it h use o f tra n s m itte d lig h t. T he a m o u n t o f edge e n h a n ce m e n t d epends on the selected se ttin g fo r d e v e lo p m e n t e le ctro d e bias d u rin g d e v e lo p m e n t. W h e n lo w e r vo ltag es o f d e ve lo p m e n t e le ctro d e bias w e re used, th e im ages sh o w e d greater edge e n h a n c e m e n t a nd m ore contrast. W h e n h ig h e r bias v a lu e s w ere used, th e im age sh o w e d less edge e n h a n c e m e n t a n d lo w e r contrast. T EE TH . T e e th are v is u a liz e d w e l l o n x e r o r a d io g ra p h s. E x a m in a tio n o f the enam el cap show s c o n s id e ra b le a n a to m ic d e ta il, e s p e c ia lly o f th e oc c lu s a l a nd m a rg in a l rid ge s and grooves. T h is is u s u
a lly m ore p ro n o u n c e d o n p re m o la rs a nd m o la rs w h e re th e fissures m ay be deep (F ig 1). A reas o f e nam el o v e rla p s h o w th e edges o f b o th ena m e l s u r faces. T h e b o rd e r b etw e e n th e ena m e l a nd d e n tin is seen m ore d is tin c tly on th e x e ro ra d io g ra p h ic im ages. O n th e x e ro ra d io g ra p h s , th e d e n tin e x h ib its a sm o o th a nd stru ctu re le ss surface s im ila r to th a t seen on c o n v e n tio n a l film s . Areas o f c e rv ic a l b u rn o u t are seen less fre q u e n tly on x e ro ra d io g ra p h s th a n on c o n v e n tio n a l film s , as th e w id e r la titu d e o f th e x e ro ra d io g ra p h s a llo w s th e la te ra l surfaces o f te eth in th e c e rv ic a l re g io n to be m o re s h a rp ly d e fin e d (F ig 2). Because o f th e edge e n h a n ce m e n t o f th e x e ro ra d io g ra p h ic process, p u lp cham bers a nd ca n als are m ore c le a rly seen o n x e ro ra d io g ra p h s th a n on c o n v e n tio n a l film s , e s p e c ia lly in th e re g io n s o f the m a x illa ry m o la rs w h e re p u lp a l a n a to m y is o fte n d if f ic u lt to d isce rn . S im ila rly , p u lp stones a nd p u l p a l d y s tro p h ic c a lc ific a tio n s are m ore re a d ily de te c te d o n x e r o r a d io g r a p h s . C e m e n tu m is n o t n o rm a lly seen o n to o th surfaces w it h e ith e r im a g in g system . CARIES. C o m p a ris o n o f th e ra d io g ra p h ic app ea r ance o f in te rp ro x im a l c a rio u s le s io n s sh ow s th a t th e m a rg in s o f these lesio ns are ty p ic a lly m ore s h a rp ly d e fin e d on x e ro ra d io g ra p h s (F ig 3). T h is is tru e fo r le sio n s re s tric te d to th e e na m e l as w e ll as fo r those p e n e tra tin g in to u n d e rly in g d e n tin . G e n e ra lly , the d e p th o f p e n e tra tio n as seen b y each system is c o m parable. E x te n s io n o f gross c a rio u s le s io n s is seen e q u a lly w e ll b y b o th te c h n iq u e s . O c c a s io n a lly , w h e n lo w se ttin g s o f d e v e lo p m e n t e le ctro d e bias are used, a djace nt enam el surfaces w i l l s h o w a d iffu s e ra d io lu c e n t area in th e area o f co n ta ct. T h is app ea r ance is a rtifa c tu a l b u t m a y suggest a c a rio u s le s io n . T h is a rtifa c t m a y be re d u c e d o r e lim in a te d b y in creasing the s e ttin g o f th e d e v e lo p m e n t e le ctro d e bias, b y re d u c in g th e a m o u n t o f ra d ia tio n expo sure, o r b y d o in g b o th . W h it e - G r a t t : C L IN IC A L T R IA L S O F X E R O R A D IO G R A P H Y
■ 811
F ig 2
■ X e r o r a d io g r a p h ( A ) s h o w s w e ll- d e fin e d la t e r a l b o r d e r s o f te e th ju s t a b o v e a lv e o la r c re s ts b e c a u s e o f
w id e r la t it u d e a v a ila b le i n x e r o g r a p h ic p r o c e s s . C o n v e n t io n a l im a g e ( B ) s h o w s a r e a s o f “ c e r v ic a l b u r n o u t . ”
F ig 3
■ X e r o r a d io g r a p h ( A ) is m a g n if ie d v ie w o f p o r t io n o f b it e w in g p r o je c t io n s h o w in g m u lt ip le c a r io u s te e th .
C o n v e n t io n a l r a d io g r a p h (B ) s h o w s c o m p a r a b le a r e a .
BONE. T h e la m in a d u ra , in c o n ju n c tio n w ith the a l v e o la r crest, is seen b e tte r on x e ro ra d io g ra p h ic im ages. T h is is m o st u s e fu l w h e n the a p ic a l p o rtio n s o f te e th are e x a m in e d fo r p e ria p ic a l disease o r w h e n th e p o s itio n o f ro o t apexes is d e te rm in e d . In d iv id u a l b o n y tra b e cu la e are also seen m ore s h a rp ly on the x e ro ra d io g ra p h ic im ages. T h is is e s p e c ia lly e v id e n t in in te r ra d ic u la r areas b u t is also n o tice a b le in bone s u p e rim p o s e d o ve r teeth. V a ria tio n s in d e n s ity and s tru c tu re o f bone tra b e cu la tio n s m ay be e a s ily ob served. T h is is im p o rta n t in e v a lu a tio n o f p e ria p ic a l bone fo r e vid e n ce o f ly s is fro m p u lp a l disease. Areas o f dense s c le ro tic bone are also re a d ily observed; o fte n m o re d e ta il is n o tic e d th a n on c o n v e n tio n a l film s . T h e s tru c tu re o f the in te rra d ic u la r a lv e o la r crest m a y be seen w ith co nside rab le c la r ity a nd m a y a id in e a rly id e n tific a tio n o f p e rio d o n ta l disease (F ig 4). PERIODONTAL LIG AM EN T SPACE. T h e p e rio d o n ta l lig a m e n t space is s h a rp ly d e fin e d on x e ro ra d io g ra p h ic im ages as the edge e ffe ct p ro v id e s sharp c o n tra s t w it h th e a djace nt dense to o th a nd la m in a 8 1 2 ■ J A D A , V o l. 99 , N o v e m b e r 1 9 7 9
d ura. T h is is p a r tic u la rly h e lp fu l in id e n tify in g in d iv id u a l roots th a t are o fte n o v e rla p p e d in m u l tiro o te d teeth. A ls o , th e apex o f th e ro o t is m ore p re c is e ly d e fin e d and m o re e a s ily e x a m in e d because o f a m o re s h a rp ly id e n t if ie d p e rio d o n ta l lig a m e n t space and la m in a dura. SOFT TISSUES. G in g iv a l tissues are m ore re a d ily seen on x e ro ra d io g ra p h ic im ages. T h is is e v id e n t b o th o n b ite w in g a nd p e ria p ic a l p ro je c tio n s . T h is c h a ra c te ris tic is also tru e fo r o th e r soft tissu e s tru c tu re s su ch as the tip o f th e nose, the lip s , and the cheeks (F ig 5). In a d d itio n , c a lc ific a tio n s o f so ft tis sue m ay o c c a s io n a lly be seen th a t are n o t e v id e n t on c o n v e n tio n a l ra d io g ra p h s. CALCULUS. C o m p a riso n o f x e ro ra d io g ra p h ic im ages w ith c o n v e n tio n a l ra d io g ra p h s sh ow s a d e c id e d d if ference in the degree to w h ic h d ep osits o f c a lc u lu s m ay be detected. X e ro ra d io g ra p h ic im ages s h o w b o th s u p ra g in g iv a l a n d s u b g in g iv a l c a lc u lu s in m u c h greater d e ta il (F ig 6).
F ig 4
■ X e r o r a d io g r a p h ( A ) c le a r ly s h o w s a lv e o la r c re s ts a n d tr a b e c u la r b o n e . C o n v e n t io n a l r a d io g r a p h (B )
s h o w s s a m e a re a .
F ig 5
■ X e r o r a d io g r a p h ( A ) s h o w s s o f t tis s u e o f t ip o f n o s e p r o je c te d o v e r r o o t s o f in c is o r s . C o n
v e n tio n a l r a d io g r a p h (B ) s h o w s s a m e a re a .
RESTORATIVE M A TER IA LS . C o m m o n ly used re s to ra tiv e m a te ria ls sh o w the same re la tiv e ra d io d e n s itie s w it h b o th system s. A m a lg a m and g o ld resto ra tio n s are e n tire ly ra d io p a q u e , w hereas p o rc e la in and p la s tic re s to ra tio n s are m ore ra d io lu c e n t. Base m a te ria ls are re a d ily d is tin g u is h e d fro m a m a lg a m or g o ld . W ith d e v e lo p m e n t e le ctro d e bias se tting s, th e great d iffe re n c e in ra d io g ra p h ic d e n sitie s o f a m a l gam a nd d e n tin m ay re s u lt in excessive edge en h a n ce m e n t in th e im age o f th is ju n c tio n . A s a re s u lt, p o rtio n s o f th e m a rg in o f the d e n tin a djace nt to m e ta llic re s to ra tio n s m a y s h o w a p e rip h e ra l ra d io lu c e n t zone. Care m u s t be ta ken n o t to confuse th is area w ith re c u rre n t caries th a t i t m a y resem ble. T h is a rtifa c t is d im in is h e d w h e n h ig h e r vo ltag es o f de v e lo p m e n t e le c tro d e b ias o r lo w e r e xp o su re s o f ra d ia tio n are used. R e e x a m in a tio n o f th e same teeth w ith h ig h e r values o f d e v e lo p m e n t e le ctro d e bias e ith e r e lim in a te s th is p ro b le m o r reduces i t to w it h in a cceptable lim its (Fig 7).
ARTIFACTS. In g eneral, th e in c id e n c e o f a rtifa c ts w as h ig h e r th a n on c o n v e n tio n a l film . A rtifa c ts u s u a lly appeared as s m a ll w h ite o r b la c k dots a lth o u g h o ccasion al lin e s w ere observed. In a ll cases, th e a rtifa c tu a l n atu re w as c le a rly e v id e n t a nd th e y w e re n o t c o n fu s e d w it h a n a to m ic s tru c tu re s . I t w as a lso n o tic e d th a t c e n tra l areas o f large m e ta llic re s to ra tio n s w o u ld o c c a s io n a lly s h o w d a rk e n in g because o f d e p o s itio n o f to n e r. P o te n tia l d iffic u ltie s re s u lt in g fro m lo w s e ttin g s o f d e v e lo p m e n t e le ctro d e bias w ere d escribed. A s w it h m o st ra d io g ra p h ic a rtifa c ts , th e greatest p ro b le m w as the p o s s ib ility o f o b s c u r in g im p o rta n t in fo rm a tio n . DOSIMETRY. E v a lu a tio n o f the param eters o f e x p o sure used in th e c lin ic and la b o ra to ry in d ic a te s th a t c o n v e n tio n a l d e n ta l ra d io g ra p h ic m a c h in e s o p e ra t in g in th e u s u a l (60 to 100) k V p range are a p p ro p r i ate fo r e x p o s in g x e ro ra d io g ra p h s . In o u r e xp e rie n ce , th e exposure tim e m a y be re d u c e d b y a fa c to r o f 2 to W h it e - G r a t t : C L I N I C A L T R IA L S O F X E R O R A D IO G R A P H Y
»813
F ig 6
■ X e r o r a d io g r a p h ( A ) d e m o n s tr a te s m o r e e x te n s iv e d e p o s itio n o f c a lc u lu s t h a n is e v id e n t o n c o n v e n t io n a l
r a d io g r a p h s (B ) o f s a m e a re a .
F ig 7
■ X e r o r a d io g r a p h ( A ) w a s p r o c e s s e d w i t h lo w d e v e l
o p m e n t e le c tr o d e b ia s a n d s h o w s r a d io lu c e n t a r e a s , a d ja c e n t t o a m a lg a m r e s to r a tio n s , t h a t a r e n o t s u b s ta n tia te d o n c o n v e n t io n a l r a d io g r a p h ( B ) o f s a m e a r e a . I n c r e a s in g d e v e l o p m e n t e le c t r o d e b ia s r e d u c e s im a g e c o n t r a s t a n d r e m o v e s r a d io lu c e n t a r e a s ( Q .
3 fo r x e ro ra d io g ra p h y co m p ared w ith th a t used fo r c o n v e n tio n a l (D-speed) film .
Operation of dental xeroradiographic processor Several in h e re n t features in the o p e ra tio n o f th e d e n ta l x e ro ra d io g ra p h ic processor are d iffe re n t fro m c o n v e n tio n a l ra d io g ra p h ic p rocedures. ROOM LIG H T PROCESSING. A s th e x e ro ra d io g ra p h ic cassettes m a y be processed in ro o m lig h t, the p ro 8 1 4 ■ J A D A , V o l. 9 9 , N o v e m b e r 1 9 7 9
cessor m ay be lo ca te d near th e ra d io g ra p h ic m a c h in e fo r ra p id access b y th e o pe ra to r. T h is can p o te n tia lly e lim in a te th e need fo r a d a rk ro o m . FAST, DRY IMAGES. T he p ro cessin g c y c le , fro m tim e o f in s e rtio n o f th e cassette in to th e p rocessor u n t il a d ry im age is a v a ila b le fo r v ie w in g , is 20 seconds. T h is gives th e o p e ra to r an o p p o r tu n ity to e xam in e th e re s u lta n t im age w ith o u t a p p re c ia b le d e la y and to in te rp re t th e x e ro ra d io g ra p h s im m e d ia te ly to de te rm in e i f a d d itio n a l p ro je c tio n s o r th e re ta k in g o f an im age is needed.
R O O M L IG H T V IE W IN G . T h e x e r o r a d io g r a p h ic im a ge appears as a p h o to g ra p h th a t m a y be v ie w e d at c h a irs id e i n ro o m lig h t, a nd th e re b y is easier to v ie w d u r in g c lin ic a l a c tiv ity . W e have n o tic e d th a t p a tie n ts a re o fte n in t e r e s te d i n v ie w in g th e x e ro ra d io g ra p h ic im ages a nd ask q u e stio n s a b o u t tre a tm e n t. T h e re b y, an e d u c a tio n a l o p p o r tu n ity fo r th e p a tie n t is p ro v id e d . H o w e v e r, th e m a x im a l a m o u n t o f in fo r m a tio n fro m th e im ages is a ch ie ve d w h e n th e y are v ie w e d w it h tra n s m itte d lig h t. R IG ID CASSETTES. In o u r e xpe rie nce , use o f r ig id cassettes does n o t cause u n d u e d iffic u ltie s fo r p a tie n ts o r operators. T h e cassettes w e re c a re fu lly p o s itio n e d w e ll in to th e o ra l c a v ity a nd a w a y fro m th e p a la ta l o r lin g u a l surfaces o f te e th in accordance w it h th e p rin c ip le s o f th e p a ra lle lin g te c h n iq u e . W h e n i t is necessary to ta ke im ages u s in g th e b is e c t in g a n g le te c h n iq u e , th e cassette m a y be s u p p o rte d in tra o r a lly w it h th e fin g e rs . REUSABLE CASSETTES. Because th e cassettes are re usable, i t w as necessary to p re v e n t m ic ro b io lo g ic a l c o n ta m in a tio n . In o u r c lin ic a l tria ls , th e cassettes w e re in d iv id u a lly w ra p p e d in s te rile , d isp osa ble , p la s tic bags befo re b e in g p la ce d in th e m o u th . T h is p ro c e d u re also p ro te cts th e im a g e re c e p to r fro m s a liv a ry c o n ta m in a tio n th a t c o u ld cause an im age a rtifa c t. SIZE OF IM AGE. D u rin g o u r tr ia l, o n ly im a g e rece p to rs th e size o f no. 2 p e ria p ic a l f i l m w e re a va ila b le a lth o u g h th e x e ro ra d io g ra p h ic pro cesso r is b e in g d e s ig n e d to p ro v id e cassettes th e size o f b o th n o. 1 a n d n o. 2 p e ria p ic a l film . T h e size o f th e re s u lta n t x e ro ra d io g ra p h ic im a g e is a p p ro x im a te ly 3 m m s m a lle r in each d im e n s io n th a n th e c o rre s p o n d in g p e ria p ic a l film . A lth o u g h n o. 1- a n d no. 2-size f ilm a c c o u n t fo r th e m a jo rity o f ra d io g ra p h s e xposed in th e g en eral d e n ta l p ra c tic e , c o n v e n tio n a l f i l m and p ro ce ssin g te ch n iq u e s m u s t be m a in ta in e d i f o th e r sizes o f f ilm are used.
Discussion D e v e lo p m e n t o f a d e n ta l x e ro ra d io g ra p h ic p ro cessor o ffe rs th e p ro sp e ct o f increa se d d ia g n o s tic c a p a b ility fo r d e n tists. T h is n e w system is d e sig n e d to w o r k w it h c o n v e n tio n a l ra d io g ra p h ic m ach in e s c u r r e n tly u sed i n d e n ta l o ffic e s . T h e x e ro ra d io g ra p h ic process is based o n w e ll-re s e a rc h e d im a g in g p rin c ip le s th a t have been w id e ly used in m e d i ca l ra d io g ra p h y . I t s h o u ld be n o tic e d , h o w e v e r, th a t th e d e n ta l u n it d e scrib e d in th is re p o rt is d is tin c t fro m th e system (X e ro x 125 M e d ic a l System ) in w id e s p re a d use sin ce 1970. A lth o u g h b o th system s d e m o n stra te th e p ro p e rty o f edge e nh an cem en t, th e d e n ta l system has a d iffe re n t system o f d e v e lo p m e n t
a n d p ro v id e s m u c h greater im a ge re s o lu tio n .18 D e n tis ts s h o u ld c a re fu lly c o n s id e r th e p o te n tia l im p a c t o f th is process o n th e ir p ra c tic e befo re d e c id in g to r e g u la rly use th is in s tru m e n t. O u r a n a ly s is is c o n s id e re d in th re e areas: Does use o f th e d e n ta l x e ro ra d io g ra p h ic system m ake a v a ila b le n e w d ia g n o s tic in fo rm a tio n ? Is th e re a n e w h aza rd associated w it h th e process? Is th is system p ra c tic a l in th e d e n ta l o ffice ? DIAGNOSTIC YIELD. T h e p rim a r y d ia g n o s tic v a lu e o f d e n ta l x e ro ra d io g ra p h y is its c a p a b ility o f p ro d u c in g im ages s u p e rio r in d ia g n o s tic q u a lity . In o u r c lin ic a l tria ls , th e d e n ta l x e ro ra d io g ra p h ic im ages c o u ld a llo w v is u a liz a tio n o f o ra l tissues w it h greater c la r ity a n d in m o re d e ta il th a n w as o b ta in e d w h e n c o n v e n tio n a l ra d io g ra p h y w as used. T h is re s u lts p r im a r ily fro m th e p ro p e rty o f edge e nh a n ce m e n t in h e re n t i n th e x e ro ra d io g ra p h ic process w h ic h ac centuates s m a ll d iffe re n ce s in d e n s ity o f tw o adja c e n t s tru c tu re s . S m a ll s tru c tu re s th a t d iffe r in d e n s ity fr o m th e im m e d ia te e n v iro n m e n t, s u c h as p e rio d o n ta l lig a m e n t, p u lp canals near th e apex o f th e ro o t, o r t h in p la te s o f tra b e c u la r bone, are m o re e a s ily seen o n x e ro ra d io g ra p h ic im ages. C ariou s le sion s w e re seen a t least as w e ll o n x e ro ra d io g ra p h ic im a g e s as o n c o n v e n tio n a l f i lm . In e x a m in in g p e rio d o n ta l disease, a lv e o la r bone m a y be s tu d ie d w it h gre ate r c o n fid e n c e th a n is c u rre n tly th e case w it h c o n v e n tio n a l film . O u r e x p e rie n c e sh ow s th a t th is n e w x e ro ra d io g ra p h ic process can d em on strate m o re s u b tle p a th o lo g ic changes in th e o ra l tissues th a n c o n v e n tio n a l ra d io g ra p h ic f ilm . I t m u s t be re c o g n iz e d , h o w e v e r, th a t o u r o bse rva tion s re p re se n t c lin ic a l im p re s s io n s d e r iv e d fr o m s id e -b y -s id e c o m p a ris o n s o f x e ro ra d io g ra p h s a nd c o n v e n tio n a l ra d io g ra p h s . I t is im p o rta n t th a t c o n tro lle d q u a n tita tiv e e v a lu a tio n s be m ade o f th e in c id e n c e o f d ete c tio n o f disease b y each system to s u p p le m e n t these o b se rva tion s. T o e va lu a te d ia g n o s tic u sefu lne ss o f a n e w p ro cess, th e p o s s ib ility m u s t be c o n s id e re d th a t use o f th e n e w system w i l l re s u lt in e rro r— e ith e r b y th e v ie w e r m is s in g p a th o lo g ic c o n d itio n s th a t a c tu a lly e x is t o r b y m is in te rp re tin g a rtifa c ts th a t resem ble n o n e x is te n t p a th o lo g ic c o n d itio n s . T h e s e p o s s ib ilitie s have been e x a m in e d in o u r c lin ic a l tria ls b y c o m p a ris o n o f x e ro ra d io g ra p h ic im ages w it h c o n v e n tio n a l ra d io g ra p h s o f th e same te eth. In o u r e x p e rie n c e , c a rio u s le s io n s a nd osseous changes w e re seen o n th e x e ro ra d io g ra p h ic im ages w h e n e ver th e y w e re seen o n co m p a ra b le c o n v e n tio n a l film . O c c a s io n a lly , h o w e v e r, a rtifa c ts w e re seen th a t o bscu re d d e ta il o f th e im age. C o n s id e rin g th a t th e s tu d ie d in s tru m e n t w as an e x p e rim e n ta l m o d e l o n its f ir s t c lin ic a l tria ls , th e in c id e n c e o f su ch a rtifa c ts w as lo w . O f greater c o n c e rn is th e o c c a s io n a l a rtifa c tu a l appearance o f a ra d io lu c e n t m a rg in a ro u n d a W h i t e - G r a t t : C L IN IC A L T R IA L S O F X E R O R A D IO G R A P H Y
815
p o r tio n o f an a m a lg a m re s to ra tio n o r th e d iffu s e ra d io lu c e n t area o n a d ja ce n t surfaces o f e n a m e l th a t suggest re c u rre n t decay. T h is c o n d itio n is m o st p re v a le n t w h e n lo w va lu e s o f d e v e lo p m e n t e le ctro d e b ia s are used to a chieve im ages w it h h ig h co ntrast. T h is p ro b le m w as re d u c e d b y in c re a s in g th e d e v e l o p m e n t e le ctro d e vo lta g e o r b y decrea sing th e ra d ia tio n e xposure. O u r e x p e rie n ce suggests th a t use o f d u a l d e v e lo p m e n t e le ctro d e b ias s e ttin g s o n th e pro cesso r m a y p ro v id e th e best re s u lts fo r d iffe re n t p ro je c tio n s o r c lin ic a l circu m sta n ce s. M o re research is re q u ire d to d e te rm in e th e o p tim a l c o m b in a tio n o f c lin ic a l, e le c tric a l, a n d ra d ia tio n e xpo sure fa cto rs re q u ire d to a chieve th e m o s t d ia g n o s tic a lly u s e fu l im ages.
Conclusions C lin ic a l tria ls o f th e e x p e rim e n ta l d e n ta l x e ro ra d io g ra p h ic syste m have c le a rly in d ic a te d th a t th e i n s tru m e n t w i l l be v a lu a b le to d e n tis try . A lth o u g h th e re is m u c h to be le a rn e d , th e c a p a c ity o f th e sys te m to p ro d u c e im ages o f h ig h d ia g n o s tic q u a lity , th e ease o f o p e ra tio n , a n d th e re d u c e d e xpo sure to p a tie n ts re p re s e n t p o s itiv e c o n trib u tio n s to th e p ra c tic e o f d e n ta l ra d io g ra p h y .
T h e a u t h o r s t h a n k M r s . C y n t h ia C a r b e r r y , t h e W o r d P r o c e s s in g C e n te r u n d e r th e d ir e c tio n o f M r s . R h o d a F r e e m a n , a n d th e a u d io v is u a l d e p a rt m e n t f o r h e lp i n p r e p a r in g t h e m a n u s c r ip t . D r . W h i t e is a s s o c ia t e p r o f e s s o r a n d c h a ir m a n , s e c t io n o f o r a l r a d io lo g y , S c h o o l o f D e n t is t r y , U n iv e r s it y o f C a lif o r n ia L o s A n g e le s , T h e C e n te r f o r
HAZARD. T h e p rim a r y b io lo g ic a l h a za rd associated w it h d e n ta l d ia g n o s tic r a d io g ra p h y (o th e r th a n in te rp re ta tio n a l e rro r) is th e p o s s ib ility o f so m a tic r a d ia tio n in ju r y . T h e e x te n t o f th is ris k , i f a ny, is u n k n o w n b u t i t is m o s t p ro b a b ly p ro p o rtio n a l to th e ext e n t o f e x p o s u r e . O u r e x p e r ie n c e w i t h th e x e ro ra d io g ra p h ic system in d ic a te d th a t th e e x p o sure to p a tie n ts m a y be re d u c e d b y a fa c to r o f 2 to 3 fro m c o n v e n tio n a l ra d io g ra p h y . It s h o u ld be fu rth e r n o tic e d th a t, i f s u b o p tim a l f ilm p ro ce ssin g te c h n iq u e s a re u s e d , th e d o s e a d v a n ta g e o f th e x e r o r a d io g r a p h ic s y s te m w i l l t h e n b e c o r r e s p o n d in g ly m o re fa vorab le. T h is re d u c tio n in dose w i l l b e n e fit b o th p a tie n ts a n d d e n ta l p e rs o n n e l e x posed to scatter ra d ia tio n .
H e a lt h S c ie n c e s , L o s A n g e le s 9 0 0 2 4 . D r . G r a t t is a s s is t a n t p r o f e s s o r , d e p a r t m e n t o f o r a l r a d io lo g y , s e c tio n o f g e n e r a l d e n t is t r y , S c h o o l o f D e n t is t r y , U n iv e r s it y o f C a lif o r n ia L o s A n g e le s . A d d r e s s r e q u e s ts f o r r e p r in t s to D r . W h ite . 1 . W o lf e , J .N . X e r o r a d io g r a p h y o f th e b r e a s t. S p r in g f ie ld ,
111, C
h a r le s C
Thom as, 1972. 2 . B in n ie , W . H . , a n d o th e r s . A p p lic a t io n o f x e r o r a d io g r a p h y i n
den
t is tr y . J D e n t 3 ( 3 ) :9 9 - 1 0 4 ,1 9 7 5 . 3 . S c h r iv e r , W . R . ; S w in t a k , E .F .; a n d D a r la k , J .D . X e r o c e p h a lo g r a p h y . O r a l S u rg 4 0 (6 ):7 0 5 -7 0 8 , 1 9 7 5 . 4 . L o p e x , J ., J r . X e r o r a d io g r a p h y
in
d e n tis tr y . J A D A
9 2 (1 ):1 0 6 -1 1 0 ,
1976. 5 . T ip n is , A . K . X e r o r a d io g r a p h y f o r la t e r a l s k u ll r a d io g r a p h s . B r J O r th o d 1 (5 ):1 8 7 -1 8 9 ,1 9 7 4 . 6 . D a v is , R ., a n d o th e r s . T h e r o le o f x e r o r a d io g r a p h y i n c e p h a lo m e tr ic r a d io lo g y . J D e n t 5 ( l) : 3 2 - 3 8 , 1 9 7 7 . 7 . H u r s t, R ., a n d o th e r s . L a n d m a r k id e n t if ic a t io n a c c u ra c y in x e r o r a d io g r a p h ic c e p h a lo m e tr y . A m J Q r t h o d 7 3 ( 5 ) : 5 6 8 - 5 7 4 , 1 9 7 8 . 8 . J o h n s o n , N . A . X e r o r a d io g r a p h y f o r c e p h a lo m e tr ic a n a ly s is . A m J O r th o d 6 9 (5 ):5 2 4 -5 2 6 ,1 9 7 6 .
P R A C T IC A L IT Y . O u r c l i n i c a l t e s t i n g o f th e x e ro ra d io g ra p h ic p rocessor w as c o n d u c te d w it h an e x p e rim e n ta l m o d e l in an in s titu tio n a l e n v iro n m e n t. N eve rthe less, in o u r e xpe rie nce , th e ease o f o p e ra tio n , th e r a p id a v a ila b ility o f th e im ages, a n d th e ease o f in t e r p r e t a t io n a v a ila b le w i t h th e x e ro ra d io g ra p h ic system are d e sira b le features th a t w o u ld assist in tre a tm e n t. R a p id d e liv e ry o f im ages m a y also h e lp th e o p e ra to r as i t is easy to ch e ck w h e n a n a to m ic re g io n s are s a tis fa c to rily im a g e d . T h e o p p o r tu n ity to im m e d ia te ly expose a n o th e r xe ro ra d io g ra p h is p ro v id e d . Use o f r ig id cassettes w as p re v i o u s l y fo u n d c o m p a tib le w i t h in t r a o r a l r a d io g ra p h y .20 T h e system is lim ite d in th a t im ages are re s tric te d to th e size o f no. 1 a nd n o. 2 film . I f o th e r sizes o f f ilm are d esire d , a fa c ility fo r c o n v e n tio n a l p ro ce ssin g m u s t be m a in ta in e d .
9 . X e r o x C o r p o r a tio n . X e r o r a d io g r a p h y f o r t e m p o r o m a n d ib u la r jo in t . M e d ic a l A p p lic a t io n B u ll 1 1 5 ,1 9 7 3 . 1 0 . F e rg u s o n , M .M ., a n d
o th e rs . A p p lic a tio n
o f x e r o r a d io g r a p h y in
s ia lo g r a p h y . I n t J O r a l S u r g 5 :1 7 6 - 1 7 9 ,1 9 7 6 . 1 1 . G la s s m a n , L . M . ; O ’H a r a , A . E . ; a n d C r e g a r , D . X e r o s ia lo g r a p h y . A r c h O to la r y n g o l 1 0 0 ( 5 ) :3 4 1 - 3 4 3 ,1 9 7 4 . 1 2 . S n y d e r, B ., a n d
o th e rs . T h e
a d v a n ta g e s o f x e r o r a d io g r a p h y f o r
p a n o r a m ic e x a m in a t io n o f th e ja w s a n d te e th . J P e r io d o n t o l 4 8 ( 8 ) :4 6 7 - 4 7 2 , 1977. 1 3 . P o r g o r z e ls k a - S tr o n c z a k , B . T r ia ls o f e m p lo y in g r a d io x e r o g r a p h y in d e n t is t r y . C z a s S to m a t o l ll( 1 2 ) : 8 7 7 - 8 7 9 , 1 9 5 8 . 1 4 . L a p in s k a s , V . A . , a n d ( x e r o r a d io g r a p h y ) a n d
L a p in s k e n e , A . V .
p ro s p e c ts o f its
u s e in
E le c tr o r o e n tg e n o g r a p h y d e n t is t r y . S to m a to lo g ia
(M o s k ) 4 7 {4 ):3 5 -3 8 ,1 9 6 8 . 1 5 . R a w ls , H .R ., a n d
O w e n , W .D . T h e
d e n t a l p r o g n o s is f o r x e r o r a
d io g r a p h y . O r a l S u r g 3 3 :4 7 6 - 4 8 0 ,1 9 7 2 . 1 6 . G r a tt, B .M .; S ic k le s , E .A .; a n d P a r k s , C .R . X e r o r a d io g r a p h y o f d e n ta l s tr u c tu r e s . P r e lim in a r y in v e s tig a tio n s . O r a l S u r g 4 4 ( 1 ) : 1 4 8 - 1 5 2 , 1 9 7 7 . 1 7 . G r a tt, B .M .; S ic k le s , E .A .; a n d P a r k s , C .R . X e r o r a d io g r a p h y o f d e n ta l s tr u c tu r e s . Im a g e a n a ly s is . O r a l S u r g 4 6 ( 1 ) : 1 5 6 - 1 6 5 , 1 9 7 8 . 1 8 . W h it e , S .C .; S t a f f o r d , M . L . ; a n d B e e n in g a , L . R . I n t r a o r a l x e r o r a d io g r a p h y . O r a l S u r g 4 6 :8 6 2 - 8 7 0 ,1 9 7 8 . 1 9 . J e r o m in , L . , a n d o th e r s . X e r o r a d io g r a p h y f o r in t r a - o r a l d e n t a l r a d io lo g y : a p r o c e s s d e s c r ip tio n . O r a l S u r g , t o b e p u b lis h e d . 2 0 . G r a tt, B .M .; S ic k le s , E .A .; a n d P a r k s , C .R . U s e o f in t r a o r a l c a s s e tte s f o r d e n ta l x e r o r a d io g r a p h y . O r a l S u r g 4 6 : 7 1 7 - 7 2 0 ,1 9 7 8 .
8 1 6 ■ J A D A , V o l. 9 9 , N o v e m b e r 1 9 7 9
