Reports & Studies

Innovative caries detection

Proface* provides a clinical aid in the detection of bacterially infected hard tooth tissue, particularly infected dentin. This way, caries excavation is more reliable than with traditional tools (probing the hardness, application of staining agents). The traditional tools only indirectly permit a conclusion on the bacterial infection of dentin. By contrast, the Proface* light probe, together with the diagnostic goggles, form a tool which can be used to directly visualize the remaining bacterially infected dentin (referred to below as residual caries) at any time and to evaluate the success of the caries excavation.

The Proface* light probe uses the so-called FACE (Fluorescence Aided Caries Excavation) method, which has been proven in different clinical studies.

before excavation

with Proface*
wth Proface*
without Proface*
without Proface*

after excavation

with Proface*
with Proface*
without Proface*
without Proface*

*A new name for our winner: Proface will from now on be called Facelight

Quantity of remaining bacteria and cavity size after excavation with FACE, caries detector dye and conventional excavation in vitro.

Lennon AM, Attin T, Buchalla W.
Clinic for Preventive Dentistry, Periodontology and Cariology, University of Zürich, Zürich, Switzerland.
Oper Dent. 2007 May-Jun;32(3):236-41.


In this in vitro study, quantitative confocal microscopy was used to show differences in the quantity of bacteria remaining in dentin after excavation with different methods. A further parameter was the cavity volume after excavation relative to the original lesion size. Teeth with dentin caries were divided into three groups of 20 each. The caries was removed by a single operator using a slow handpiece and a round bur. In the first group, Fluorescence Aided Caries Excavation (FACE) was carried out: violet light was used to illuminate the operating field and the operator observed the cavity through a high-pass filter and removed the orange-red fluorescing areas. The second group was excavated using Caries Detector, while the third group used conventional excavation. After excavation, cavity volume was measured; samples were stained for bacteria with ethidium bromide, and they were examined using confocal microscopy under standardized conditions. The bound stain was quantified in terms of fluorescence intensity on the confocal images. Total pixel intensity was significantly lower in the FACE Group than in the Caries Detector group(p = 0.046) and in the conventional excavation group
(p = 0.021). Differences in cavity volume relative to original lesion size were not statistically significant
(p = 0.86, 0.35 and 0.51). Within the limitations of this in vitro study, it can be concluded that FACE is more effective in removing infected dentin without significantly increasing cavity size when compared to conventional excavation and excavation with the aid of caries detector dye.
PMID: 17555174 [PubMed - indexed for MEDLINE]

The Ability of Selected Oral Microorganisms to Emit Red Fluorescence

A.M. Lennona, W. Buchallaa , L. Brunea b, O. Zimmermannb , U. Grossb , T. Attina,
a Department of Operative Dentistry, Preventive Dentistry and Periodontology, and
b Institute of Medical Microbiology, Georg August University Göttingen, Göttingen, Germany
Caries Res 2006;40:2-5 (DOI: 10.1159/000088898)


Some novel caries detection and excavation devices rely on the ability of bacteria to produce red fluorescing compounds. The aim of this study was to examine the ability of selected oral microorganisms to emit red fluorescence. Streptococcus mutans, S. oralis, S. salivarius, S. sobrinus, Lactobacillus fermentans, L. casei, L. rhamnosus, Actinomyces naeslundi, A. israelii, Prevotella intermedia, and Fusobacterium nucleatum were inoculated onto Columbia agar with haemin and vitamin K and incubated anaerobically for up to 7 days in the dark. The resulting bacterial colonies were excited using filtered xenon light (405 ± 20 nm) and digitally photographed through a 530-nm high-pass filter. The red and green portions of the colony fluorescence were analyzed using a computer program and the red/green ratio was calculated. All colonies emitted both red and green fluorescence. The green outweighed the red portion for the following species (in descending order)
S. oralis, S. salivarius, S. mutans, F. nucleatum and S. sobrinus. The red portion was higher for the following species (in descending order) P. intermedia, A. naeslundi, A. israelii, L. fermentans,
L. rhamnosus and L. casei. With all the bacteria examined, one color portion generally outweighed the other, giving the visual impression of either red or green fluorescence. We conclude that red fluorescence is well suited to detection of the bacteria which cause dentin caries but it is not suitable as an indicator of the presence and activity of the streptococci involved in initial caries.
Copyright © 2006 S. Karger AG, Basel

Efficiency of 4 caries excavation methods compared.

Clinic for Preventive Dentistry, Periodontology and Cariology, University of Zürich, Switzerland.
Oper Dent. 2006 Sep-Oct;31(5):551-5.


This in vitro study compared the efficiency (time taken to excavate and successfully remove bacterially infected dentin) of Fluorescence Aided Caries Excavation (FACE), caries detector dye (CD), chemomechanical excavation (CS) and conventional excavation (CE). Teeth with dentin caries were assigned to 4 groups (n= 25). Caries excavation was carried out by one operator. In the FACE group, the operating field was illuminated with violet light. The operator observed the teeth through a high-pass filter and removed orange-red fluorescing areas with a slow speed bur. In the CS group, Carisolv was applied to the cavity using CS hand instruments and allowed to act for 30 seconds before caries was removed. In the CD group, caries was removed using the Caries Detector and, in the CE group, conventional excavation was carried out using visual-tactile criteria. The excavation time was recorded. Undecalcified thin slices (8 microm) were prepared, stained with giemsa and examined using light microscopy. The excavation time (median) was significantly shorter for FACE (3 minutes, 3 seconds) compared to CS (5 minutes, 8 seconds, p=0.015), CD (5 minutes, 26 seconds, p=0.003) and CE
(4 minutes, 2 seconds, p=0.025). Histology showed remaining bacteria in significantly fewer (5/25) FACE samples compared to CS (15/25 p=0.004) CD (12/25 p=0.037) but not significantly fewer than CE (11/25 p=0.069). In conclusion: the excavation result with FACE is equal to CE and superior to CD and CS but requires a significantly shorter excavation time.
PMID: 17024942 [PubMed - indexed for MEDLINE]

Fluorescence-aided caries excavation (FACE) compared to conventional method.

Lennon AM.
Department of Operative Dentistry, Preventive Dentistry and Periodontology, Georg-August-University Göttingen, Göttingen, Germany.
Oper Dent. 2003 Jul-Aug;28(4):341-5.


A recent study showed that orange-red fluorescence in carious dentin could be used to detect residual caries (Lennon & others, 2002). This study compared the ability of a new fluorescence-aided caries excavation technique (FACE) with the conventional method. Forty extracted teeth with occlusal dentin caries were selected. The teeth were bisected longitudinally through the center of the lesion. Lesion depth and width were measured and the teeth were divided into two groups of 20, each with the same average lesion size. The tooth halves were reassembled and fixed by embedding the roots in acrylic resin. Access cavities were prepared using a high-speed handpiece and diamond fissure bur. In the FACE group, violet light (370-420 nm) was fed into the fiber optics of a slow-speed hand-piece, so that it illuminated the operating field. The cavity was observed through a 530-nm high-pass filter and orange-red fluorescing areas were removed. In the conventional group, a sharp probe was used to detect soft dentin, which was removed. One-half of each tooth was stained for bacteria using Ethidium Bromide and examined using Confocal Laser Scanning Microscopy (CLSM). Bacteria were present in significantly (p=0.037) fewer FACE samples (3) compared to conventional samples (9). It can be concluded that the new method is more effective than conventional caries excavation.
PMID: 12877417 [PubMed - indexed for MEDLINE]

Residual Caries Detection Using Visible Fluorescence

Á.M. Lennonab, W. Buchallaab, L. Switalskia, G.K. Stookeya
aDepartment of Preventive and Community Dentistry, Oral Health Research Institute, Indiana University School of Dentistry, Indianapolis, Ind., USA;
bDepartment of Conservative Dentistry, Preventive Dentistry and Periodontology, Georg August University of Göttingen, Germany
Caries Res 2002;36:315-319 (DOI: 10.1159/000065956)


This study investigated the ability of a new fluorescence method to detect residual caries in vitro. Gross caries was removed from 40 teeth with D2 caries. Samples were excited with violet-blue light and viewed through a 530-nm high-pass filter. Residual caries (orange-red fluorescing dentin) was detected in all samples. Further tooth substance was removed from half of the samples until no residual caries was detectable using the new method. Half of the samples remained untreated.
A blinded examiner checked all samples for residual caries using DIAGNOdent, a visual tactile examination, and Caries Detector® dye. Presence or absence of residual caries in each sample was determined using a fluorescent nucleic acid stain in conjunction with confocal microscopy. The new method, Visible Fluorescence, had the greatest sensitivity, specificity, percent correct score and predictive values of any of the methods tested. The new method had significantly higher percent correct score than any of the other methods and significantly higher specificity than visual tactile and Caries Detector. It was concluded that Visible Fluorescence is an improvement on the currently available aids for residual caries detection.
Copyright © 2002 S. Karger AG, Basel