Abilitatea Diagnod.- c.aprox.molari

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In vitroability of a laser fluorescence device in quantifying

approximal caries lesions in primary molars

P. Celiberti, V.M. Leamari, J.C.P. Imparato, M.M. Braga, F.M. Mendes *

Department of Pediatric Dentistry, Faculdade de Odontologia, Universidade de Sao Paulo, Av. Lineu Prestes 2227, Cidade Universitaria,

Sao Paulo 05508-000, SP, Brazil

1. Introduction

The detection of caries lesions is normally accomplished using

visual, tactile and radiographic methods, but these methods

are subjective, which normally leads to a low reproducibility.

The search for a less subjective and examiner-dependent

diagnostic method has led to the development of devices,

which aim at providing quantitative and more reproducible

method.1

Recently, a new laser fluorescence device, named DIAG-

NOdent pen (LFpen) (Kavo, Biberach, Germany), was intro-

duced intothe market.2,3 This new device is basedon the same

principles of an earlier device, the DIAGNOdent (Kavo,

Biberach, Germany) and has been developed to detect occlusal

and approximal caries. The LFpen approximal probe is

designed with a prism which deflects the laser beam 1008,

making it possible to access more properly the approximal

surfaces, presenting accurate and reliable results in detecting

approximal caries lesions.2,3

However, a method for caries diagnosis should not only be

able to detect the presence of caries and its stage, but also be

able to monitor its progression or assess its inactivation. For

this, the method needs to be reproducible and present

correlation with parameters of caries lesions, such as lesion

depth, especially amongst non-cavitated lesions, which are in

need to be controlled. Since LFpen has presented good

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a r t i c l e i n f o

Article history:

Received 4 March 2010

Received in revised form

5 May 2010

Accepted 6 May 2010

Keywords:

Laser fluorescence

Approximal caries

DIAGNOdent

Reproducibility

Primary teeth

a b s t r a c t

Objectives: This in vitrostudy aimed at evaluating the ability of Laser Fluorescence device

(LFpen) in quantifying approximal caries lesions in primary molars.

Methods: Two examiners assessed 123 approximal surfaces of primary molars using the

DIAGNOdent pen (LFpen). Surfaces were determined to be either sound with white-spot

lesions or have small cavitations. After sectioning, lesion depth was determined through

polarized light microscopy. The intra-/inter-examiner agreement was calculated using

intraclass correlation coefficient (ICC) and BlandAltman analyses. Furthermore, Spearman

correlation coefficients (Rs) were calculated between LFpen readings and lesion depth.

Results: Correlation between LFpen values and lesion depth was low for both examiners

(Rs = 0.36 and 0.51), especially when cavitated lesions were excluded from the analysis

(Rs = 0.22 and 0.40). For all surfaces, ICC revealed intra- and inter-examiner reproducibility

values of 0.75 and 0.63, respectively, but when only non-cavitated surfaces were analyzed,

these values decreased (0.41 and 0.33, respectively).

Conclusions: LFpen readings present low correlation with approximal caries lesion depth

and lowreproducibility, especiallyin white-spotlesions.Therefore, thedevice could notbe a

suitable method for monitoring non-cavitated approximal caries lesion in primary molars.

# 2010 Elsevier Ltd. All rights reserved.

* Corresponding author. Tel.: +55 11 3091 7835; fax: +55 11 3091 7854.E-mail address:[email protected](F.M. Mendes).

a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m

journal homepage: www.intl.elsevierhealth.com/journals/jden

0300-5712/$ see front matter # 2010 Elsevier Ltd. All rights reserved.

doi:10.1016/j.jdent.2010.05.005
mailto:[email protected]://dx.doi.org/10.1016/j.jdent.2010.05.005http://dx.doi.org/10.1016/j.jdent.2010.05.005mailto:[email protected]


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accuracy and reproducibility in detecting decay on approximal

surfaces, its use in monitoring caries on these surfaces was

proposed.3 This ability has, however, not yet been tested.

Therefore, the aim of this in vitrostudy was to assess the

potential use of LF in monitoring quantitatively approximal

caries lesions in primary teeth through the assessment of its

correlation with lesion depth and its reproducibility.

2. Materials and methods

After obtaining approval from the local Committee for Ethics

in Research, 84 primary molars, 42 primary canines and42 first

permanent molars were selected. All primary teeth were

extracted by dental practitioners in Sao Paulo, Brazil (0.7 mg/L

fluoride in water supply). Prior to the extraction, written

consent was obtained from the patients or the patients

guardians, and they were informed that their teeth would be

used for research purposes in the future. In regards to the first

permanent molars, the teeth were donated by the School of

Dentistry, University of Sao Paulo, using their Bankof Teeth.Following the experiments, the researchers returned the teeth

to the university. All procedures were in accordance with

Resolution 196/96 of the National Health Council (Brazil).

After extraction, the teeth were stored frozen in individual

containers at 20 8C with no contact with any storing

solutions until use. During the experiment, the teeth were

stored in individual plastic containers and thawed at room

temperature (ca. 24 1 8C) for 4 h. To avoid dehydration of the

samples, a cotton roll soaked in distilled water was placed, at

the bottom of each individual container, assuring 100%

humidity in the closed container and avoiding contact

between the tooth and the cotton roll.4

The approximal surfaces were then cleaned using arotating brush and pumice/water slurry and rinsed for at

least 6 s. In order to simulate approximal contact points/areas,

the teeth were placed in arch models and fixed with melted

utility wax in the following sequence: a primary canine, a first

primary molar, a second primary molar, and a first permanent

molar from the same arch (Fig. 1). Care was taken to simulate

the contact points as best as possible, and its presence was

confirmed using dental floss.

The evaluations were performed only on the approximal

surfaces of primary molars. Therefore, the distal surfaces of

canines and mesial surfaces of first permanent molars were

not evaluated. Surfaces with approximal restorations, hypo-

plastic pits, frank approximal cavitation extending to facial or

buccal surface, or to the marginal ridge (the cavitation, when

present, could not be detected visually when in contact with

the adjacent tooth). Presence of large carious lesions on

smooth or occlusal surfaces that could in some way interfere

the approximal readings, and surfaces with difficulty insimulating the contact point were excluded, yielding in final

sample of 123 approximal surfaces.

All examinations were carried out by two trained exam-

iners. One benchmark examiner (M.M.B.) trained the others to

perform examinations using the laser fluorescence method

and visual inspection. For this purpose, the other 15 extracted

teeth were used. No calibration procedures were performed.

These teeth were not included in the samples. The examiners

were directed to analyze each site independently and

disagreements were discussed later.

Before the examinations, teeth were defrosted as previ-

ously described and were again frosted after the examina-

tions. A DIAGNOdent pen device (Kavo, Biberach, Germany)attached to Probe tip1 (for approximal surfaces)was employed

according to the manufacturers instructions. Before each

measurement, the LF device was calibrated against a ceramic

reference (standard calibration), as well as on a predetermined

sound, smooth surface of every tooth, so that a zero value of

fluorescence could be obtained (individual calibration). This

laser fluorescence reading was electronically subtracted from

the readings of the approximal site under examination. Teeth

were kept humid and were air dried for 3 s with a 3-in-1

syringe previously to examination using LF. The detection-

side of the LF device tip was introduced underneath the

contactarea and moved until the peak value wasreached. One

measurement on the facial and one on lingual interproximalspace were carried out and the highest value from both

measurements was recorded. One examiner, chosen random-

ly, repeated all measurements a week after to assess intra-

examiner reproducibility.

After all examinations were completed, the teeth were

removed from the arch models and their surfaces were

examined using visual inspection. Specimens were positioned

about 30 cm from examiners eyes. With no magnification, an

assessment was carriedout after air drying for 5 s with aid of a

ballpoint probe and light reflector. The examiner (VML)

classified the surfaces as sound, with either non-cavitated

caries lesions or with cavitated caries lesions. This examiner

was not aware from the results previously obtained whenteeth were examined positioned in the arch model.

Subsequently, teeth were embedded in acrylic resin and

sectioned mesio-distally in slices ca. 250mm thick, using a 0.3-

mm-thick diamond saw mounted in a microtome (Labcut

1010; Extec Co., Enfield, CT, USA). The sections were manually

ground and polished with silicon carbide paper (400, 600, 1200

and 4000 grits in sequence) to about 100 mm. Then, the

sections were examined in a microscope with transmitted

polarized light (Leica DM750, Leica microsystems, Heidelberg,

Germany) at 50 magnification and quartz plate. The sections

were imbibed in distilled water. The contrast between sound

enamel (negative birefringence) and the demineralized enam-

el (positivebirefringence) wasdetected andthe software (Leica

Fig. 1 Arch model used to simulate teeth position and the

contact points.

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Qwin, Leica microsystems, Heidelberg, Germany) determined

the depth of the body of the lesion (mm).

The statistical unit in this study was the approximal

surface. The intra-/inter-examiner agreement, using the

entire values of the device, was calculated using intraclass

correlation coefficient (ICC) and 95% confidence interval

(95%CI), and BlandAltman analyses. Furthermore, Spearman

correlation coefficient (Rs) and 95% CI were calculated

between LFpen readings and lesion depth. As cavitated lesionshould undergo restorative procedures, all analyses were

repeated after exclusion of the lesions which showed enamel

surface discontinuity on visualtactile inspection. All analyses

were carried out using statistical software (MedCalc 9.3.0.0;

MedCalc, Mariakerke, Belgium), and the level of significance

wasp < 0.05.

3. Results

The visual and tactile inspection revealed 34 (27.6%) sound

surfaces, 60 (48.8%) surfaces with non-cavitated caries lesions

and 29 (23.6%) surfaces with cavitated caries lesions. The

correlation between the LFpen values and lesion depth for

both examiners were low when all 123 surfaces were analyzed

(Rs = 0.359; 95%CI = 0.1940.504 for examiner 1; Rs = 0.511;

95%CI = 0.3670.631, for examiner 2). This correlation was

found to be even lower whencavitated surfaces were excluded

from the analysis (Rs = 0.215; 95%CI = 0.0140.401; Rs = 0.396;

95%CI = 0.2100.554 for examiner 1 and 2, respectively).

When all surfaces were analyzed, the ICC revealed a good

intra-examiner agreement for the LFpen device (ICC = 0.745;95%CI = 0.6580.813). The inter-examiner agreement was

found to be lower and with larger range of differences

between readings done by different examiners (Fig. 2). The

ICC was 0.632 (95%CI = 0.5240.720).

When only non-cavitated surfaces were analyzed, the

intra-/inter-examiner reproducibilities were found to be

considerably low. Intra-examiner reliability presented

ICC = 0.411 (95%CI = 0.2450.553), and the value for inter-

examiner reproducibility was ICC = 0.328 (95%CI = 0.186

0.456). The mean of differences as well as the limits of

agreement (mean 1.96SD) forboth inter- andintra-examiner

agreement can be seen on the BlandAltman plots (Fig. 2).

When the plots were analyzed, we could observe that the

Fig. 2 BlandAltman plots for intra- and inter-examiner reproducibility of all samples and only non-cavitated surfaces.



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disagreements are more pronounced in lesions with higher

LFpen readings, indicating higher variability in measurements

of more advanced caries lesions (Fig. 2).

4. Discussion

The present study evaluated the potential use of LFpen inmonitoring quantitatively approximal caries lesions in prima-

ry teeth through the assessment of its reliability and

correlation with lesion depth. Previous studies have investi-

gated the performance of the device in detecting approximal

caries lesions,3,5,6 but the ability of LFpen in quantifying these

lesions has not been assessed. Our results showed that the

device presented low correlation with lesion depth and poor

reproducibility. These findings, therefore, could contradict the

previous assertion that the device could be able to monitor

caries progress or arrest.3

In order to determine the agreement using absolute LF

readings, ICC was carried out.7 The method of Bland and

Altman8 was additionally performed in order to showdeviations from the LF readings and indicate the range

between the upper and the lower limit of agreement between

LF readings performed by different examiners. Both analyses

were performed twice, firstly using all samples and then,

strictly considering non-cavitated surfaces. This last step was

carried out in order to assess the reproducibility of LF pen on

surfaces in need of non-operative treatment, according to the

concepts of minimal intervention dentistry, which advocate

the adoption of preventive measures on non-cavitated lesions

in enamel and dentine.9

After being submitted to preventive measures, non-

cavitated surfaces need to be monitored over time in order

to state the success of the treatment or to detect lesionprogression. However, approximal caries lesions diagnosis

and control has seen limited success by means of clinical

examination, due to restricted access in this area and the

location of these lesions. Radiographs are able to aid detection

of approximal lesions within enamel or already progressed

into dentine,10 estimating lesion depth. However, besides the

hazards of ionizing radiation, radiographs with similar film

position and X-ray beam angulation, which would provide an

adequate control of lesion progression, are more difficult to

achieve. Thus, a quantitative, valid and reproducible method

in monitoring approximal caries lesions and that reduces the

need of frequent control radiographs is wished.

Although a previous study has claimed that the LFpencould be useful in monitoring approximal caries lesions due to

its high reproducibility,3 we have found low intra-/inter-

examiner reproducibility, especially when cavitated lesions

were not considered. This is consistent with a previous in vivo

study on primary molars, which also showed a lower

agreement values at white-spot threshold.6 Furthermore,

higher ICC values and lower range values were observed in

the intra-examiner analysis than in the inter-examiner one,

what is in agreement to an earlier study performedon occlusal

surfaces.11 The Bland and Altman analysis showed that the

lowest range between the upper and the lower limits of

agreement could be seen for intra-examiner agreement, in

spite of surface condition, meaning that a lower measurement

deviation could be observed when the same examiner

performed both LFpen readings.

Astothepresenceofcavitatedsurfacesintheanalysis,lower

range values were observed only when non-cavitated surfaces

were included.As this lowerrange does notmeanthata smaller

deviationinthemeasurementsoccurred,thiscomparisonisnot

acceptable. The range is dependent on the measurement value

available for the device. Non-cavitated surfaces are likely toexhibita lower range, as thesesurfaces yieldlowerLFpen values

than cavitated ones. A previous study on occlusal surfaces

divided the sample in two intervals, and showed a lower range

for the samples under the cut-off point of 30.11

Besides the low reliability, a low correlation between LFpen

valuesandhistologicallesiondepthwasobservedinthepresent

study. This correlation was even lower when cavitated lesions

were removed from the sample. This low correlation between

LFpen values and histological examination indicates that the

method didnot properly measure the actual statusthe disease.

Despite the fact that the device shows numerical values from 0

to99,LFpendoesnotworkasaquantitativemethodinassessing

approximal caries lesions. Therefore, the method can detectaccurately approximal caries lesions,3,5,6 working as a qualita-

tive method, but it cannot quantify these lesions. The first

version of the device presented higher correlation with smooth

surface caries lesions in primary teeth,12 probably because of

the easier access to this type of lesion and direct contact of the

tip withthe lesion, whatprobably didnot happen in approximal

assessments with the new device.

Some authors have affirmed that lesion depth assessed by

polarized light microscope is not the main property of caries

lesions to indicate the severity, and the mineral loss would be

more appropriated. However, lesion depth is the second most

important property which indicates severity of caries lesions.

Furthermore, significant correlation has been observed be-tween mineral loss and lesion depth.13 Despite of this, further

studies shouldbe conducting evaluating the ability of LFpen in

quantifying mineral loss of caries lesions instead of lesion

depth.

When only non-cavitated caries lesions were considered,

LFpen was shown to perform worse than in detecting

cavitated lesions at the approximal surface, corroborating

previous findings.6,14 This can be due to its mode of function,

where fluorescence is detected from changes in the organic

content due to bacterial metabolites, rather than deminerali-

zation. As a cavitated lesion is obviously more infected than a

non-cavitated one,15 a better performance of the LFpen device

is to be expected in these lesions.In conclusion, LFpen is not able to quantify approximal

caries lesion depth and presents low reliability in primary

molars, using an in vitro study design. Therefore, the results

suggest that method could not be a suitable method for

quantitatively monitoring approximal caries lesion in primary

molars, especially non-cavitated lesions.

r e f e r e n c e s

1. Pretty IA. Caries detection and diagnosis: novel

technologies.Journal of Dentistry2006;34:72739.

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2. Aljehani A, Yang L, Shi X. In vitro quantification of smoothsurface caries with DIAGNOdent and the DIAGNOdent pen.

Acta Odontologica Scandinavica 2007;65:603.3. Lussi A, Hack A, Hug I, Heckenberger H, Megert B, Stich H.

Detection of approximal caries with a new laserfluorescence device.Caries Research2006;40:97103.

4. Francescut P, Zimmerli B, Lussi A. Influence of differentstorage methods on laser fluorescence values: a two-year

study.Caries Research2006;40:1815.5. Braga MM, Morais CC, Nakama RC, Leamari VM, Siqueira

WL, Mendes FM. In vitro performance of methods ofapproximal caries detection in primary molars.Oral SurgeryOral Medicine Oral Pathology Oral Radiology and Endodontics

2009;108:e3541.6. Novaes TF, Matos R, Braga MM, Imparato JCP, Raggio DP,

Mendes FM. Performance of pen-type laser fluorescencedevice and conventional methods in detecting approximalcaries lesions in primary teethin vivostudy.Caries Research2009;43:3642.

7. Lin LI. A concordance correlation coefficient to evaluatereproducibility.Biometrics1989;45:25568. 1989.

8. Bland JM, Altman DG. Statistical methods for assessingagreement between two methods of clinical measurement.

Lancet1986;1:30710.

9. Tyas MJ, Anusavice KJ, Frencken JE, Mount GJ. Minimalintervention dentistrya review. FDI Commission Project197. International Dental Journal2000;50:112.

10. Wenzel A. Bitewing and digital bitewing radiography fordetection of caries lesion. Journal of Dental Research2004;83:C72C75.

11. Kuhnisch J, Bucher K, Hickel R. The intra/inter-examinerreproducibility of the new DIAGNOdent pen on occlusal

sites. Journal of Dentistry2007;35:50912.12. Mendes FM, Siqueira WL, Mazzitelli JF, Pinheiro SL,

Bengtson AL. Performance of DIAGNOdent for detection andquantification of smooth-surface caries in primary teeth.

Journal of Dentistry 2005;33:7984.13. Ten Bosch JJ, Angmar-Mansson B. A review of quantitative

methods for studies of mineral content of intra-oral carieslesions.Journal of Dental Research1991;70:214.

14. Braga M, Nicolau J, Rodrigues CR, Imparato JC, Mendes FM.Laser fluorescence device does not perform well indetection of early caries lesions in primary teeth: an in vitrostudy.Oral Health and Preventive Dentistry 2008;6:1659.

15. Kidd EA, Banerjee A, Ferrier S, Longbottom C, Nugent Z.Relationships between a clinical-visual scoring system andtwo histological techniques: a laboratory study on occlusal

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