Endod Dfiil I'liiwnalol I9')6: 12: 54 59

PrinWtt in Dciinuiik , , ( / / ri^hl.^ icscrval

'O Miiiik.\i;aaid 1996

Endodontics &Dental Traumatology

/.V,S',V I) 109-251)2

Detection of pulse in oral mucosa anddental pulp by means of optical reflectionmethodOikariuen K, Kopoht 11, Makiniemi M, Herrala Iv Ueieelion of])ulse in oral mucos;t and denial pnip by means of optical relleclicinmethod, IMUIOCI Denl Traumalol 1'!!)(); 12: 5\ .')<). © Munksgaard,

AbsUael Iliis pitper desc tibes a new syslem in wluc h opticalrelleeUmce is used to lest the pulse and \'itality ol oial nuicosa ordental ])ulp. Radiation at red (660 nm) and near inlra-red (c'i,̂ )O nm)wavelengths are directed through a thin probe-. T h e beam is cli-nx ted inio tissue and rcfleclcd back, Plcth\'sni()graphy i,s nsed tomeasvire the pulse rate from the- right forelingei\ Rellec ted radiationi,s related lo plethysmogram using a compnler. Preliminary liiidingsrelating to tlte lips, and gingiva in 9 healthy x'oltinleers were promis-ing. Preliminary lests showed that vital and nonvital JHI1]JS rcdeclecltlie radiation dillereutly, Pulpal ])vilse did not always correspond to])lelhysmc)gi am from the lighl forelinger.

K. Oikarinen\ H. Kopola ,̂M. Makiniemi^, E. Herrala^Departments of 'Oral and Maxillotacial Stirgery,Instittite of Dentistry, ^Electrical Engineering,Technical Faculty, University of Oulu, 'Oral andMaxillafacial Department, Oulu University hlospital,•'Optoelectronics Laboratory, Technical ResearchCentre of Finland, Oulu, Finland

Key words: pulse oximetry; tisstia vitality: toothvitality; pulse

Kyosti Oikarinen, Institute of Dentistry, University

of Oulu, Aapistie 3, SF-90220 Oulu, Finland

Act;epted for pulicafion March 28, t995

Pulp neerosis is a common comj^lication after trau-matic tootli injury, II is found on the average in LV/ool leeth wilh closed apicc-s after siibliixalion, T.')"/i>alter luxation, and lOO'Vo after intrnsion (1), and inmore than 90"/'(i after a\ tilsion (2). Ptilp nee rosis is alsocommon after LelM)rt 1 osteotomy (3), and in leethlelt iu lite line of mandibular fractures (1).

Pulp necrosis should be diagnosed on llie basis ofa variety of denial linclings e.g. lenclei ness on per-cussion, increased mobility, ])ain, crown discoloialionand racliographical widening of the- periapical peri-odontal sj)acc (5). IJ|) to now il has been pos,sible toa,s,sess tooth vitality more or less inclireetly. Thermal\ilalily testing has bec-n inlraduced (6). Electrical pulptesting gives information on nerve stipply, itot circtila-lion in tlie pulp. 'lV,sling can be tinplea,sanl andsttulies in clogs ha \e shown ihat electrical \ i talomelrycan ai led ftnic-tioning of cardiac |)acH'inakeis (7).La,ser Dopi:)ler based ou lasc:r and ultrasound havebeen tisecl, e.g. to delermine o,s,seoiis blood How inosteomyelitie patients (c")) and gingival blood status (9),Since the 19H0s rc])ort,s ha \ e been pulished on laserDoppler diagnosis of ptilp \italily in men and animals(10-13). The lechnologv reveals blood How, and

54

iherelore it is not necessarily a reliable method in situ-ations in which |iulp chamber has rcc:luced. Theec|tiipment is at ]:)resent expensive.

Tec hiiic|ues have been used to sttidy clillerenccs inlight absor|:)lion ol one wavelength in healthy and un-healthy animal teetli (14). Ultraviolet light (15, 16)and speclrophotometry (17, IB) have also been nsedin sliidies of tooth vitality. It has recently been re-ported that pulpal pulse eau be cletected better usingwavelcngth,s of less than (iOO nm ihaii higher wave-lengths ('l9).

In (his pajx-r, preliminary ITSUILS using a new typeof system are cleseril)ed. Ojitieal reflection \ i ta lometry(ORV) i,s based on j^iilse o.ximclry, O R V could alsobe used for noninvasive delermination of blood Howand to sltidy snpcrlicial circulation in tlic oral mucosaa n d skill.

Material and methods

Pulse oximetry

Pulse oximelry is widely used for continuous le-eord-liig ol the blood oxygen levels. Absorption of light byoxygenated (Hbo) and by cleoxygenated haemoglobin

Pulpal pulse & optical reflection vitalometry

( i.'̂ measured (20 22). Radiation is dirc-cic-dthrongh a linger or earlobe and absoiptious arc esti-mated. Absoipliou curxes lor bolh oxygenated (̂ Hbo)and cleoxygenated haemoglobin (HbiK)x^ •"''' known,and ]Milse oximetry calculates the relationships be-tween ihese two c ur\es al two waxeleugths (approxi-matelly ()()() nm and H,")0 nm). Oxygen saturation isdeliiied as the ratio between oxygenated Hb to totalHb (=Hb,,-(-Hb|),,x) (20),

Small amounts of carboxyhacmoglobin ^C'OHb)and mcthaemoglobin (MetHb) whic h ha\e absorbtioii|)rc)]3eities dillering from those of l lbo and Hbnoxdo not tisnally interfere with determination of oxygensaturation if ihc)' are [Mesenl in the blood in low con-centrations (2 1),

Optical retlection vitalometry

ORV is being dexelopecl in collaboialion b\- the l)e-ljarlmenl of l'̂ lec trie al lMtgineeriiig, Tec huical l'acultyand the Uepartment of Oral and MaxillofacialSurgery, Institule of Deniistry, LTui\'ersity of Oulti,and the Oploeleclronic s Laboraiorv ol the TechnicalResearch (!eiUie of Finland,

l-'or ihe |:irc-liminary measurenieuls fibre opiicprobe was coustructcci. I he dexice conslrnc-lcd con-tains two light-emitting diodes (Ll^n"), an oplical re-c-ei\er, signal-processing unit and a conipnter. TheLl'iDs are used in a pulse mode-, emitting x\a\c-leiigtlisof t)60 and 850 nm. The light pulses are transmittedalong the fibre optic" probe and lllnmmated the tissuetested, Rellected light from the tissue is transmitted\ia the- ])rol)c- to the- detector. The- signal rc-cc-i\c-cl iseli\ided into two e haniu-ls in the- signalpreHe-ssing elec-lie)ele-s e)ne' le)r e-ach wa\ c-lc-nglli, Ihe signals areamplified and lilterc-d. 1 he two signals are di\idedinto AC and DC c-ompone-nts. Analogue-to-digitale e)n\c-isie)n is iiiide-rlake-n by the- ee)iiiputer.

The right forc-liugc-r is subjected to ]:)lethysmogra-]ihy. Pulse rale is dcri\c-d from the- rc-sulls and used in]3roc-c-ssing signals Irom the- target tissue, Ihe- c-om-ptilc-r program displays a jnilsc- ]:)lethysmogram for llic-tissiu- at red (660 nm) and infrared (850 nm) \va\e-Ic-iigths,

The fibre optic probe is a bundle dixided into thirel^arts a red transmittc-r, a nc-ar-infr.ired transmitterand a reccix'cr, in the jjroportions lt)"i), 20" o andIt)" 0, repeetixely.

To c-liminatc- ellect arising from noise- from sur-rotmelmgs anel motion of the- ]irobe, dexicc io hold itbetween the tippc-r and lower teelh during testing wasconstriu-ted ilM,!̂ '-"̂ - bi- lb). This allowed measurc-mentfrom the- uppc-r and lowc-r U-c-lh, gingix a and lips. Thematerial is plastic and can easily be sterili/,c-cl and dis-inlectc-d.

Preliminary measurements

Inilially, the capacilx' of xital and nonxital teeth toabsorb light c-nc-rgy was dc-tc-rininc-cl by passing liilra-rc-d and rc-cl lighl through an extrac-ted tooth, andthrough a xital eeiitral iueisor ol a 2 l-yc-ar-olcl man.Pulse Wiis determined lii xarious iissuc-s m 9 hc-althyxolunteers. A relc-rc-ncc- pulse- lor all ine-asiire-nie-nt,sw.is cle-U-rmine-cl plc-lhysmograpliically. from the right

Table 1, Means and medians of difference in the peak ot pulse curves at redand infrared wavelengths between the measurements from various tissuesand reference plefhysmogram from the right forefinger

/');;, /, The- piobc- aiic:l ils holdc-r spcTJally dc-signc-d to c-limiiialc-

r l l rcls of luolioii (liirini;- incastirc-niciils rclalini;' In lh

and a looth (b).

Lower lipsUpper lipsUpper gingiva

Lower gingivaUpper canine

Upper lateral incisorUpper central incisors

11

76874

34

Mean(ms)

168

36116110190187

Red

Median(ms)

20202510

220

200245

Infrared

Mean

232

493115

19730

Median

2015801055

200100

55

Oikarinen et al.

lorermger ol each subjecl, luformation during a !')()-smeasurement with the same- pulse as the refe-re-iue]:)lethysme)gTaiTi was summarizc-cl (i.c-, measurable- re-sults). Ihe tops of these enrvc-s wc-rc- calculated byeomputc-r and lhc- mc-an clillc-rc-neie-s bc-lween pulse

Time (0.01s)

/'/!;, 2 . A b , s ( ) i ' | ) l i ( ) i i c i i i A c s i c T a t i i m l o t i p p c T ( a ) a n d l o w e r ( b ) l i p o f

a 2 ! - \ c a t - o l d m a n . D a s h e d l i n e i,s t h e i n l o r n i a t t o n i c c c i \ ' c d I r o m

r c ' l ( T c ' n c ( - p t c t h y s i n o L ^ r a p h s f r o m l h c l i n t ^ c r , I t i l i a r c d s i g n a l ( f ' , ) ( ! t m i ;

i,s s h o w n a s a s o h d i h i n l i n e a n d i h r r<-d s i g n a l ( l ) ( i l ) n n i ; a s a i h i c k

line.

eui-\'es al rc-el and infrarc-d waxe-l(-iigtlis for the te-stc-cltissues and the referc-ncc- forefinger ]3lethysmograniswc-re analyzc-cl.

l'cHirier and mx'erse l'durier translorniations xverepc-iibrmed to eliminate misreaclings catisc-d by move-mc-nl of the object. After Fourier transform signalshave- be-en filtc-rc-cl in frec|ue-nce lex'el. Iiix'ersc- l'ciuriertransforins have- be-en made- fre)in filtered signals.

Results

Tests fre)m lowc-r lijxs gaxi- measurable- re-sults in 7 xe)l-untee-rs. 1 he- mean e;lille-re-iice in pulse- e-urxe-s at redand infrare-el wavek-ngtlis were 23 and 16 ms rc-spec-(ix'c-|y (Table 1,) Measurc-inc-nts Irom lhc- tippc-r lipsyic-lcled me-asurabk- results e)ii (i persons. The- nic-aiidc-lay was 2 ms at infrare-d and 8 ms at red xvave--length,s (Tal)le- 1,). Absorption etirves in i-elation te) thenp|:)e-r and le)xvc-r lips e)l'a 24-ye-ar-old man are shownin T'igs, 2a,b. Mc-asuremeiits made- in the- ni^yjer at-tac hc-cl gingiva could be calciilate-d for 8 and from thelox\c-r gingix'a for 7 subjeets, 'The- mc-an dc-lays iu ptilseCLirx'c-s (al inliiirecl and rc-d xvax'c-lc-nglhs rc-spc-ciixc-ly)xvere 49 ms and 3 I ms.

Pulse (-iirx'es from uppc-r and loxvc-r gingixa for a25-year-olcl woman arc- shown in Fig. 3a,b.

The first measurement relating to pulpal bl(5od wasof the energy of liglit ])a,ssing lh)-ough x'ital and non-xital teeth. Light c-nergy ]3assing through nonvital, ex-tracted teeth x'aric-d betxveen 8(i5 and 1200 nVV.

400

300

200

100

0

-100

•200

•300

-400

Time (0.01s)

Time (0.0is)

/'((;, ,), A b s o r p l i o i i ctiiA'c-s rc-lalinjr l o ihc- t ippc-r (a) a n d lowc-r fb)

al lac h c d ! i in j ; i \a oT .i 2 ," i -year-old wc j i i i an . D a s h e d l i ne is ihi- i n l o r -

m a l i o n r(-e<-i\'ed I r o m rc - le rence p l c - l h y s i n o t ; r a p h s IVoii) t h e l i n g e r .

I n f r a r e d s i g n a l ,){,")() nin,: is s h o w n as a so l id (hiii l ine a n d llu- r e d

s i g n a l (l)()l) n m ) a s a t h i e k line-.

56

I3

1000

600

600

4C0

200

0

-200

-403

Time (0.01s)

Time (0.01s)

B/% 4. Absoi-jjtion c-tirvc-,s relating to the gingival third oflhc- c town ofi h e n p p e r e a n i n e (a) a n d n i a x i l l a r y a l t a e h r d g i n g i v a (b) ol a I t l - y i s n -

o l d m a n . D a s h e d l i ne is t h e i n l o i n i a t i o n r e e e i v c d I r o m relc-ienec- p l c -

t h y s m o g r a p h s f r o m t h e l i n g e r . In Ira r e d s i g n a l i'>,)() n m ) i,s ,sho\\ n a s a

so l id i h i n l i ne a n d t h e r e d s ign. i l itilit) n i n j as a t h i c k l i n e .

'Through vital tc-etli it xarie-d from 350 lo 750 liW.'The ratio bc-txveen these txvo xvas about 0,(i,

A pulse- re-latmg to the gingix'al third ol an iijjpercanine in a -lO-ycar-old man is slioxvn in Fig. 4a. ThediHe-rc-nec- in pulse- m rc-lalion lo lhc- relerc-iice wa,s 130ms. The- result lor upper attached giiigix^a in the samesubjc-ct is shoxvn in Fig. 4b. The dilTcrencc in relationto tlu- rc-fc-re-nce was 160 ms. A pulse eurxe, from ilu-

Pulpal pulse & optical retlection vitalometry

Inverse Fourier transform (filtered in freq-domain)

Time (0.01s)

Time (0.01s)

I-'is;. :'). , \ l ) s ( ) i p i i o n c t t rxc 's r e l a t i n g t o t h e g i n g i \ ' a l U i i rd o f d i e c r o w n

o f d i e l imc- r c c n t r a f i n c i s o r ,.ii a n d l o \ v c r a l t a c l i e d g i n g i \ a (b! o f a

-i,T-yc-ar-old ni . ) i ) , D a s h c - d l i ne i l lnstratc-s tin- i n l b r n i a l i o n rc-c"ei\c'd

f r o m the- leferc-nc c- p l c - t l n s m o g i a p h s I r o m ( h e l i n g e r , Inf rarc-d s i g n a l

(JV")() n i l ) ' is s h o w n as a so l id t h i n l i n e a n d t h e r e d s i g n a l ()t)() n n i '

a s a l l i ick line-.

Fourier transformt5| ' —

Frequency (Hz)

Fii^. a. A s t i m i n a i i z c - d l-'oiiric-r t r a n s f o r i n a l i o n r i - l a l ing l o a n iip|)c-r

c e n t r a l inciscji ol a 2 , ' ) -yca r -o ld w o n t a n , I hc-rc is a p e a k .tt I H z .

a n d r e l l e c l a n c c s a t '2 1 1 / .iiicl 3 1 1 / a r e s e e n .

50 100

Time (0.01s)/')' ', 7, ln\t-rsc l 'onru-r I ranslormal ion ol c nr\'(- m I'lg, (),

gingixal ihird of ihc- croxMi of a loxver cc-ntral incisorol a 25-yc-ar-old man is shoxvn in Fig, 5a. The diiTer-c-iice in relation to the refereiie-e x\as 200 ms. Therc-sull ol mc-asurc-mc-ut in relation to the- loxver at-taelied gingixa is alsei sheixvn (Fig. 5b). 'Flic- diirereneexvas 70 ms.

Measurements re4ating le) an nppc-r cc-ntral incisorof a 25-year-old xvomaii are summarized in Fig. 6 and7. Ing. 6 is a T'ourier transformation. Intensity x\ashigh at loxv free|uencics (0 0.5 Hz), perhaps bec-auscol moxement of the probe duriug measurement andnoise from the- surroundings. There is an intensityi:)eak at 1 Hz and lesser ones at 2 Hz and 3 FT/,. In-xersc- I'cniric-r translormation taking into account c:>nlythe- arc-as ol these three frequencies resulted in sym-mclrical pulse curxcs. Results at infrared and redwaxc-lengths as xsell as the rc-fc-rc-nc c- photoplethysmo-graiii arc- shc)x\-ii in Fig, 7.

Discussion

1 he measurement of oxygen in tissues by means oflight is based on the- faet that pheitons ]Kissing thrcmghhuman tissue arc- attenuated by absoriitioii and byboundaries. Absoiption is ,s])ectrally scnsitixT cs-]5eeially in the near infrarc-d range x\hc-re organomet-allic- iiiolc-c-ulc-s suc-li as haemoglobin liaxc- charactc-r-lstical absorption spectra that shift xvith cixvgcnation(23).

Ill nro ojMical spcctroscopy is a ni(-tlioci for mcasnr-ing oxygen concc-iitration in brain tissue c-xeii xvithoutjjulsatile blood and during circulatoiy arrest. Themeasurement is based on ojjtical relleetion and cc:)m-]M'iscs a light source- and a receiver set at various dis-tances apart, 'The- mc-thod is able to difTerentiate thede]Mh ol the informaticMi aeeording to the distanee

57

OikarJnen et al.

from thi- source-. This rlislanc-c- c a n x'aiy I rom a fc-w

millimc-tre-s lo thrc-e < e-nlimc-lrc-s (24j,

'I1ic-se prc-l imiiiaiy lc-,sts on c)]Mical re-(lc-eiioii x'ilal-

e)me-try showe-d some- prc jmis ing as xve-ll as seimc- e o n -

Il ict ing rc-sull,s, 'The- sysle-m is basc-d on e)plic-al r<-llc-c-

t a n c e abso rp l io i i bill nc-c-cls an a r te r ia l pulse- lor the

n ieasurem(-n t a n d is in this re-spe-c( s imi la r lo jjulse

oxinic-try. 'The- clillc-rc-nee from convc-nt ional ptilsc- ox i -

mc-| iy is thai (he- .•il)soi-ption is mc-astirc- from tx-(le-c'(ccl

i n s t ead ejf transmitlc-el l ight.

1 c-sts made- e)n lips gax'e- me-asural)lc- rc-stills in all

ease-s anel wc-rc- c-asy lo inlc-rprc-t, 'This is bc-catise the

lips arc- xvell x 'asculanzc-d. The- d i l l e r enees in t he

highc-st ptilse |3C-ak be-txve-en xvavc-lengths at rc-d o r in-

Iraic-cl lighl anel re-le-iencc- p h o l o p l c - t h y s m o g r a m in

b o t h nppc-r a n d lowc-r lips w e r e small a n d in t he san i e

d i r e d i o n i.c-, the pulse fi-om the- lips w a s e)ii a v e r a g e

a le-xv millise-c-onds late-r i h a n ihe- refere-iue- pholeiple--

t h y s m o g r a m , 'This is c-xplaiiu-d by lite- faet tha t t he

piilsc- r a l e in clillere-nt p a r t s e)f the- be)cly \ a r i e s d e p e n d -

ing on lac-tors such as ao r l i c liijinl impc-clancc- (25), It

d id no t sc-c-in lo make- a n y cliHe-re-ne-e- whe-the-r the-

l^i'eibe- was pre-ssc-d aga ins t the- lip o r jtisl lotichc-cl ils

suiiacc-, 'This is bc-cause n o c^onipression e)l the- vessels

e)eetirrc-cl a n d thc-rc- wc-re- not e-noiigh b l o o d x'c-ssels for

the meas t i rc -ments .

This mc-thod for m e a s u r i n g b l o o d o x y g e n c-ould

sc-rxc- in anac-sthesia eon t ro l for ehilclrc-ii. U s i n g a fin-

gc-r probe- in pulse- e)xinic-lry is not alxvays rc-liable, as

the e-e)mpre-ssioii c-an catise- tc-inpe)raiy clisappe-arane-e

of i^erijihc-ral (-irculatie)n,

'The- resiills from lhc- a l lachecl g ingixa clc-pc-iulc-cl

lnue-h e)n the pie-ssiire e-xe-rlc-d by the- probe-. If llie

probe- xvas c-om))ressc-cl on the g ing iva n o ]iulsc- c o u l d

be- (Ic-le-ele-cl. 'This is e-xphiine-el by Ihe llun that ihe ,soft

tissue- in the- attaehe-cl g ing ixa is rathc-r th in a n d its

m e c h a i i i e a l (-onipression r e d u c e s siipc-rlicial b l o o d cir-

eiilatiem, 'The- mc-an de-lax' in the- h ighes t |3e-ak of|DUISC-

eurvc-s at rc-d a n d inlVared wavc-le-iigths from the rc-fer-

(-iice- pulse e-urvc- in b o t h uppe-r a n d loxvc-r g ing iva was

simi lar le) tha t in lips anel was a le-w te-ns e)f inilli-

sec-onds b e h i n d ihal from lhc- l inger . Slill, thc-ie- xve-re-

se)me- e-xce-ptiems, Pe-iiiaps due- le) intc-rinclivielual xa r i -

a t ion Ol' to some- c c)in])re-,ssion of ihe soli li,ssue by the-

p r o b e .

I hc-se- resLills shovv(-el, h o w e v e r , iha l puLse- e a n be-

a c h i e v e d from the- gingival t issue in m o s t ease-s. 'This

o p e n s ne-xv o p p o r l uni t ies for nor i invas ivc s(udi(-s o f ihe

elle-cts of s m o k i n g , mecl ica t ion , i r r a d i a t i o n c-tc. on thc-

siipcrlif-ial ( i n -u l a t ion ol ' soft ti,s,suc-s. In purUculur

there- is a ne-e-d Ui assc-ss t he i n t e g r a t i o n of skin, m u -

cosal a n d frc-c- m i c r o v a s c u l a r Haps,

P r i m a r y n ieasure-menls e)n te-eth c o n c e r n i n g the- d e -

cre-asc in (he lighl (-nc-rgy- g a v e t he c-xpected rc-sul(s,

since- more- e-nergy was al)se)rbe-cl in vital t h a n in ne)n-

vital tc-c-(h, 'This s h o w e d that b l o o d in vilal | )u(p lisstie

m u s t h a x e a b s o r b e d s o m e light e n e r g y as found by

D i a z - A r n o l d c-t al, (11) xvlio iisc-cl a single- x\axe-Ie'ngth

te) le-st the- ab s o rp l i o i i of e-nipty a n d bloe)d-lilled t e e t h .

In ihe-se- prc- l i inmary le-sis il was clillieeill to e.iblain

in lormal ie)n lre)in t ee lh . He)x\-e-xc-r, the- le-sls she)x\e-el a

dillere-nee- l)e-lwe-en llu- me-asnri-me-nls h-e)m iippe-r

tee th a n d nppe-r g ingixa a n d e o n k l the-re-lbre- be- inte-r-

pretccl to c o n i c l i o m two clillere-nl soiircc-s,

F 'u r thc r analys is of the- d a t a t ising l''ouric-r a n d in-

vcrsc I'c)uric-r tran,slc)rmalic)iis g:i\c- c-\e-n more- p / o n i -

isiiig rc-sults. 'The Fotiric-r I r a n s f o r m a t i o n shox\c-el a

h igh in(e-nsi(y at (hc- hear ( he-at lre-c[tieiicy' (1 Tl/) .

W h e n t he in tens i ty at this lree|tie-ney x\as ana ly /c -d

toge-ther wi th harmeinic- intensitie-s at 2 Tl / a n d 3 H z ,

xvhicli lilte-re-d e)til t h e e-lleets e)f ne)ise- a n d m o l i o n , a

symnte-trieal pn lse eurxe- was e)l)tainc-cl. This a p p r o a c h

will be usc-cl lo analy/c- the- rc-sulls e)f future- e-xi)e-ri-

mc-nts,

I he a i m e)l this re-pe)rt x\as te) prc-sc-ni prc- l i inmaiy

resul ts xvith a nexv type of sys tem xvhicli co u l d se rve

as a n o n - i n v a s i v e , pa in le s s a n d harmle-ss x ' i ta lometer .

'The i n s t r u m e n t is n o w bc-iiig furtlic-r cic-velopc-cl xvith

]5art ieular attc-ntion to the- pi-e)l)lems reeeix ' ing mc-asur-

ab l e i n f o r m a t i o n from lhc- pul]ial c-irculation a n d c-al-

c u l a t i u g the ra t io of oxygeuatc-cl to clc-oxygc-uatc-d

h a e m o g l o b i n s I rom ptilse curx'c-s at rc-el anel infrare-d

w a v e l e n g t h s . T'orthe-oming ]irc))e-e-ts incitidc- dex 'e lop-

me-nt of a more- eet inpaet ins t rnmc-nt Ibr use in a n

ax'ei-age- dc-ntal p r a c t i e e .

References

1, A M ) H I : / \ S I ' : , N I ' ' I \ I , I ' l i lpal h e a l i n g alic-r h r x a l i o n i n j u r i e s a n d r o o t

Irac t u r c in t h e p e r n i a n c n l d e i i l i t i o n , h'jidod Drill Iiiiiimolol 1!)1!9;

5: I I I I :•! I,

2 , () t tsARtM,N K , ( i tNDKXCtt K K l l , P l I t l l R {,. 1 ,,Ue ( o m p l i -

c a t i o n s o f l u x a t i o n i n j u r i e s to I c c l h , luiilod DrnI 'Ilaiiiiialnl i9M7;

3: 2')(i :')02,,'!, Kiu>\\Ki. R M , I}K,\I)\- ( ; | , , 1''K,\JH: JW, Iboili pulp ihai iges lol-

lowing \r l''ort 1 maxillary oslc-otomy in a pr imate model, t'li7 Oral Maxillofac Sm.s, 1990; 2!l: I 7,

1, ()tt-^xt<iNt,N K , L A H I I ) , lOvUsi iA A M , P r o g n o s i s o f t c c th lelt in

l h c line- o f m a n d i b t i l a r I r a e t t i r c s , Endod Denl 'Iriiiiinnlol 191)0: (i:

177 IfiL',

,'), ANi)ki:Asi',N J O , / \ K I ) R I ; A S 1 ' , N I'Wl ' I c x l b o o k a n d e o l o r a l i a s oT

I r a n m a l i c injnrie-s l o l h c l e e l h , N h i n k s g a a r d I 9 ' ) l , ( l o p e n -

h a g e n ,

(), h'nss / , 1 R ( ) \ V H R I | ) C ; F , 11. B K N D K R I B , R I C K D M , ' H , S O R I N S , .As-

s e s s m e n t o( r e l i ab i l i t y o l ' c leclr ic al a n d t l u - i m a l p t i l p I c s l i n g

a g c n i s , ; / / • : « ( / « / 19»l) ; /:',• SOI 'M).

7, U ' i )oM,Kv I J J , W o o D w ' o K r i i ), l)()nn,s | l , , ,A p r c l i i i ) i n a r y c v a l i i -

a l i o i i o f l h c e l l e c l s o l ' e l e c t r i c a l pul ] ) t e s t e r o n d o g s w i l h a i t i -

l icial | ) ac ( - i i i akc r s , 7 , l « / DrnI A.uor l f ) 7 l ; IV.): \{)9\] \ | ( ) | ,

'!, \X',VNNl'ol(s K , (;,.\/|.,i,His li , l i l o o d How in j . iw b o n e s . i l l c i t c d

by chronic ostc-omyclilis, I'lr J Oral MiixiUiijdr Sura. 1991; 2'.):

117 I"),'{,

9 , I'lAAU t ) . \ . ( ) B I , R C ; l ' /V H o r i c i w A Y CiA, ( J i n g i v a l l ) l o o d How

i))ca,siiic-d vvilli a la,sc-i' D o p p l e r Ilt)wi7]eli-r, 'j Prrioil lies l')H(i-

•21: 7\\ r,,"),

10, (;A/,Ki,it:s li , ( ) i , ( ;Aur 1,, f',i)\\Ai,r B, Rc-sloied vilaliU' in l u x a t e dteed) assc-ssed b y laser D o p p l e r l l o w i i u i e r , Endod Drill 1 laiiinalol

19BU; </; 265-268,

1 1 , t^AMSAV DiS, , \ R r f X J , M A R r i N r : x ,S,S, Rel i , ib i l i l \ - o f p u l p , i l

b l o o d - I l o w nu-as t i rc -mi ' i i t s n l i l i / i n g lasc-r D o p p l i - r l l o w m e l i A , /

Drill Res 1 9 9 1 ; 7d: I 127 I ISO,

12, O u ' . A R i I,, CiA/i , i , i t is B, l.iNi)ii-,SiR()MHKRi; t ' , Las(-r D o p p l e r

tlc)Wiiu-lry in a s s e s s i n g \ i t a l i l y in l u x a t e d p e r m a n i - n t l e e l h , till

Endod J 198H; : ' / ,• SOO :U)t),

IS , lNcairi ssDN , \ R , T R O N S I / M J I., 1 II :RSII K , R I X ' A CiC, E l l i i a c y of

laser Dopplc-r l lowmc-ler in dc - t e imin ing pt i lp xi tal i ty ol h n m a i i

leelh, h'.ndod Drill •tiamnalol 199 1; ld:\',:\ !i7,

I I , D I A / - ; \ R N ( ) I , I ) , \ M . \ \ I I , C ; ( ) X I . 1 \ , . A R N O L D M , \ , ( )]) l i ( ,I1 dc-tc-c-

l i o n o f p t i l p a l b l o o d , , " / Endnd 1 9 9 1 ; 2d: l l i l Hi!!,

1,''), 1 0 R I ; M , X , N 1 ' ( ' , l ' l l r a \ i o l i - t l igh l .is a n a id to i - n d o d o n t i c d i . i g -

n o s i s , till t-.ndnd J WKVM Hi: 1 2 1 1 2 l ) ,

11), H i L i , C M , The- c-IIic.uy o t I r a n s i l l n m i n a l i o n in \ i t a l i t v l es l s , Inl

Endod J 19i!(i; i:>: I 9 i ! 2 0 1 ,

17, Niss , \N R . ' l ' t« ) i ' i , M , / i i A N i : C - D , CaiANca-, B, D u a l w a \ e -

l e n g t h s p c - e t r o p h o l o m e t i y a s a d i a g n o s l i e test ol d i e ])til])

c h a m b e r conti-nis. Oral Sinv Oral .\trd Oral t'alhol 1992; 7I:'M\

18, SciUNK'rn.ER J M . \\Ai,i,(:r | , \ , l'lilse oximelry as a diagnostic

tool of pulpal vitality, J t'jidod 1991; / ; , • 488 190,

Pulpal pulse & optical reflection vitalometry

19, 1 R , \ \ \ A M , 1 l o f R i t u a i i H , I K A W A K , O p t i c a l e h a r . u tcrist ics ol

h n t n . m c-xlrac ted t ee th a t id the possible- . ipp l ica l ion ol p b o l o -

| ) l c lhys inograp l iy to t he hni i ) ;m | )n lp . Air Oral I-Sinl 1 9 9 1 ; ,')',<A'

821 8 2 7 , '

20 , 'ri;Mi>i;R K K , B A R R I ; R S ] , l'tilsc- o \ i m e l r \ , AnurslhrMologr 1989;

7/A- 9 8 Ulf!,

2 1 , , \ i , i ; \AM)iR C : M , ri;i,i,i;R 1.1',, t h < o s s j B , Pr ine ip lcs ol pnlsc

o x i m e l r y ; rheoix- l ica l . \nd pracl ic . i l c o n s i d e r a l i o n s , .\iir.\lli Analii

19119: (iH: St)!i :i7l),

2 2 , SllKl'llKKl) , \ 1 ' , R A N D A I , \ r . SlKlNKI, J M , Si 11 IMAI/Kl, J I ., .All

o x i m c l c r Ibr m e . t s n r t n g h e m o g l o b i n eone t -n l r . i t ion a n d o x \ gc-n

c o n t c n l , .[ill J riirsnd 1989; : ' ; ) / , • 170,") 1 7 1 1 ,

2!'>, H A / K K I ( ) , r,XMi'RA M , ( , ) i ianl i t , i l i \c a n a K s i s of h e m o g l o b i n

ox \gc -na l i on sl.itc itl the' ta t b t . n n m silti by n e a r mlr;irc-d si)ec-

irophoionn-tiy, 7 .I/)/'//%v,vm/ 1988; (i4: 796 802,2 1 , MciCoRMiciK PW, SriavARr M, C^oivrrixG MCJ, Dt;]c)XNV M.

I,i-;wis ( I , ,At'SM,\\ )1, Nonin \ asi\(- t'erebr;il oplical s])ccloscopy

for moni tor ing ccrcl)r,il oxyge'ii dc-li\ery ;tnd h c m o d y n a m u s ,

Cnliral Carr .\trd 1 9 9 1 ; 19: 8 9 9 7 ,

2 ' ) , B t R A i l i M R , K \ c ) \ v r i ; x ( i ( ; , ( . A M P U K L I , K B , T w o a i l c i i a l c-l-

Icc l i \ c r c l l c c l i n g s i l i - s n i ; i \ , i p p ( - a r a s o n e - l o t h e l u - a r l , i'lmilal

Rrs 1 9 9 1 ; li!l: !i,") 9 9 ,

59