AC-impedance spectroscopy and caries detection

Abstract

De tec tion and moni tor ing of the com plex pro cess of dem in er ali zation and re min er ali sa tion by the den tal car ies is a den tist's chal lenge. Even car ies start ing as a sub surface dem in er ali za tion of enamel, may prog ress to the un der ly ing den tine and, even tu ally, to cavi ta tion of the sur face [14]. Ac cu rate di ag no sis be fore cavi ta tion oc curs would per mit tar geted pre ven tive treat ment, thereby signifi cantly im prov ing den tal health and re duc ing the need for ex pen sive drill ing and fill ing [10]. Con ven tional di agnos tic meth ods in volv ing vis ual in spec tion and the use of sharp den tal ex plorer tools de pend on sub jec tive clini cal crite ria such as color, tex ture, soft ness and re sis tance to re moval. These meth ods are good for the de tec tion of larger or cavi tated le sions. How ever, they are not suit able for the de tec tion of early den tal car ies be cause of poor sen si tiv ity and speci fic ity. Rou tine den tal ra dio graphs also lack the abil ity to de tect early cari ous lesions on enamel sur face. Ap proxi mately 30-40% min eral loss is nec es sary be fore ra dio graphs can de tect the cari ous lesion. It can take a few months or longer for this ex tent of dem in er ali za tion. There fore, bet ter di ag nos tic tools are needed to de tect early cari ous le sions and help pre vent dental cavi ties. Over the last years, vari ous tech niques have been ex plored to ad dress the need for bet ter de tec tion tools to di ag nose early den tal car ies. These tech niques include mag ni fy ing loups, di rect digi tal ra di og ra phy, digi tal im ag ing fiber-optic tran sil lu mi na tion, elec tri cal con ductance, quan ti ta tive light-induced fluo res cence, laser-induced fluo res cence, auto fluo res cence, mul ti pho ton im ag ing, infra red ther mo gra phy, te ra hertz im ag ing, op ti cal co her ence to mo graphy, ul tra sound, Ra man spec tros copy and oth ers [1,2,11,14,15,16]. In spite of nu mer ous stud ies evalu at ing dif fer ent tools with re spect to car ies de tec tion, car ies di agno sis con tin ues to be a chal leng ing task for the den tal prac ti tio ner. Es pe cially oc clu sal car ies is a clini cally dif ficult one due to the com plex mor phol ogy of the fis sure and fossa sys tem and fre quent pres ence of stain ing. Ad di tionally, the ex ten sive use of fluo ride and re min er al iz ing agents seems to de lay cav ity for ma tion. There fore, the ac curate de tec tion in the pre cavi ta tion stages is very im por tant for un der tak ing proper pre ven tive and re stora tive pro cedures and avoid ing un nec es sary treat ment.Among al ter na tive tech niques, meas ure ment of elec trical re sis tance has shown the most prom is ing. Car ies di ag no sis by elec tri cal meas ure ment was in tro duced into den tistry many years ago. Even in 1878, Magi tot's first sug ges tion was to use elec tric cur rent for car ies de tec tion [15]. The method is based on the phe nome non that den tal enamel, con sist ing largely of hy droxy...

Comparison of visual, impedance spectroscopy and laser fluorescence methods in detecting early carious lesions on occlusal surfaces

“…A particular interest has been enjoyed currently by noninvasive diagnostic methods based on physical phenomena, using knowledge of the changes taking place at the ultrastructural level and in chemical composition of enamel in the course of carious process [2,3,14].…”

Use of Digital Diagnostic Aids for Initial Caries Detection: A Review

“…When caries occur, the porosities in dental hard tissue increase in size and contain more electrically conductive fluids from the oral cavity compared with the sound tooth. Since the porosities are filled with this ionic fluid, there is a decrease in electrical resistance and an increase in electrical conductance [55,56]. Electric-based caries-detecting approaches can be categorized as electrical conductance measurement and alternating current impedance spectroscopy, based on the nature of the frequency of the electric current.…”

“…The electrical conductance measurement device uses a single, fixed-frequency alternating current to measure the electrical conductance of a carious tooth [55]. The measuring electrode is designed to fit into deep pits and fissures to be in contact with a minuscule amount of dentinal fluid to complete the circuit [57].…”

Selected caries diagnostic methods

“…Quick examination, exact and repeatable measurements. [3,4] Energy conversion technology Enables assessment of tooth tissues crystal structure using photothermal radiometry and luminescence (The Canary System).…”

“…The electronic measurement of tooth hard tissue impedance is based on enamel physical properties, i.e., the mineral density of the examined tooth hard tissues, and is characterized by high specificity and sensitivity. The device is easy to handle, enables a quick, painless examination and guarantees exact and repeatable measurements [3,4].…”