Occlusal caries detection with KaVo DIAGNOdent and radiography: an in vitro comparison

Relationship between bacterial infection and evaluation using a laser fluorescence device, DIAGNOdent

The aim of this in vitro study was to investigate the relationship between bacterial infections in carious dentin when detected by two different methods -- polymerase chain reaction (PCR), and a laser fluorescence device, DIAGNOdent. Dentin was removed every 300 micro m in the direction of the pulp chamber in 10 extracted molars with occlusal dentin caries and 3 extracted sound molars. Dentin surfaces were evaluated using DIAGNOdent, and dentinal tissue samples were removed by using a round bur before and after each removal. Bacterial DNA in the dentinal tissues was detected by PCR, using primers based on the nucleotide sequence of a conserved region of the 16S rDNA, and yielded a PCR product of 466 bp. The rates of bacterial detection increased as the DIAGNOdent values increased. In the 10 specimens, the lowest DIAGNOdent value at which bacteria were detected was 15.6; at DIAGNOdent values below 15.6, no bacteria were detected. The results of a receiver operating characteristic (ROC) curve for the DIAGNOdent values showed that the area under the ROC curve was 0.91. This study clarified the relationship between the DIAGNOdent values of dentin caries and the rates of bacterial detection.

A follow-up study of the use of DIAGNOdent for monitoring fissure caries in children

OBJECTIVES

The aim of this study was to evaluate the utility of the laser fluorescence device DIAGNOdent for monitoring occlusal caries longitudinally as part of a routine dental check-up in a public dental clinic.

METHODS

Children aged 7-8 and 13-14 years at baseline participated in the study. As part of two consecutive dental check-ups with a mean interval of 1,19, years, 423 permanent molars and 315 primary molars in 81 children were examined visually and using DIAGNOdent by one dentist. In teeth where, as judged by visual examination, caries had emerged or progressed during the follow-up, the DIAGNOdent values had increased significantly from the baseline.

RESULTS

In permanent teeth with a change in visual score from sound to enamel or dentin caries, the mean DIAGNOdent value increased from 24 to 37 and in primary teeth from 8 to 40. The increase in DIANGOdent values correlated positively with the increase in visual score. The mean DIAGNOdent value at baseline was significantly higher in teeth that became carious than in those that remained sound during the follow-up. For permanent teeth with a visual reversal from inactive or active enamel caries to a sound surface, the mean DIAGNOdent value decreased from 36 to 24.

CONCLUSIONS

These results suggest that DIAGNOdent is useful in monitoring occlusal caries in both permanent and primary molars.

Nonintrusive, noncontacting frequency-domain photothermal radiometry and luminescence depth profilometry of carious and artificial subsurface lesions in human teeth

Nonintrusive, noncontacting frequency-domain photothermal radiometry (FD-PTR or PTR) and frequency-domain luminescence (FD-LUM or LUM) have been used with 659-nm and 830-nm laser sources to detect artificial and natural subsurface defects in human teeth. The major findings of this study are (1) PTR is sensitive to very deep (>5 mm) defects at low modulation frequencies (5 Hz). Both PTR and LUM amplitudes exhibit a peak at tooth thicknesses of ca. 1.4 to 2.7 mm. Furthermore, the LUM amplitude exhibits a small trough at ca. 2.5 to 3.5 mm. (2) PTR is sensitive to various defects such as a deep carious lesion, a demineralized area, an edge, a crack, and a surface stain, while LUM exhibits low sensitivity and spatial resolution. (3) PTR frequency scans over the surface of a fissure into demineralized enamel and dentin show higher amplitude than those for healthy teeth, as well as a pronounced curvature in both the amplitude and phase signal channels. These can be excellent markers for the diagnosis of subsurface carious lesions. (4) PTR amplitude frequency scans over the surface of enamels of variable thickness exhibit strong thickness dependence, thus establishing depth profilometric sensitivity to subsurface interfaces such as the dentin/enamel junction.

Evaluation of Several Techniques for the Detection of Secondary Caries Adjacent to Amalgam Restorations

The objective of this study was to determine the ability of several techniques to detect natural secondary caries adjacent to proximal class II amalgam restorations. Two sites were selected and marked on each of 50 human extracted posterior teeth. Three examiners visually characterized each site independently for signs of demineralization (VI), ditching presence (VD), and color change, and utilized light-induced fluorescence (QLF), and infrared laser fluorescence (LF) techniques. The teeth were sectioned through the selected sites, and the severity of each lesion was determined by confocal laser scanning microscopy (CLSM) as the 'gold standard'. Agreement among examiners was assessed using weighted kappa statistics and showed fair to moderate correlation with all techniques. Sensitivity, specificity, positive predictive value (PPV), negative predictive value and accuracy were determined by utilizing three arbitrary CLSM thresholds. Higher sensitivity was indicated by the QLF and LF than by VI. For PPV and accuracy, QLF and LF showed values higher or similar to VI. Low sensitivity was found for VD. The results obtained in this study suggest that LF and QLF may improve the ability to detect early secondary caries around amalgam restorations.

Effect of alteration in organic material of the occlusal caries on DIAGNOdent readings

DIAGNOdent is a laser fluorescence device used for dental caries diagnosis in occlusal and smooth surfaces. Despite the promising preliminary results, the molecules involved in the increase of fluorescence in carious lesions remain unclear. The aim of this study was to compare the laser fluorescence readings before and after changes in the organic material of occlusal carious lesions in primary teeth. Twenty-four primary molars stored in saline solution with at least one site with occlusal caries were divided into two groups. The control group had 17 sites with caries and the experimental one had 16 sites. The carious lesions were measured with laser fluorescence. The experimental samples were then removed from the storage solution and immersed in a 2% sodium hypochlorite solution for 24 hours. After washing with water, the teeth were measured again with the laser fluorescence device. The teeth of the control group were submitted to the same procedures, but saline solution was used instead of the sodium hypochlorite solution. A statistically significant reduction in the mean of the readings after immersion in the two tested solutions compared with the initial readings was observed in both groups, but the decrease was statistically higher in the experimental group (p < 0.0001). In this study, the data indicate that changes in the fluorescence of carious lesions measured by the laser fluorescence are mainly due to the organic content alterations rather than to the mineral loss.

White spot lesions around brackets: in vitro detection by laser fluorescence

Demineralization around orthodontic brackets is one of the side-effects of orthodontic treatment. However, simple methods for its early detection, quantification and monitoring are lacking. Therefore, the aim of this investigation was to evaluate red laser-light induced fluorescence for measurement of demineralization around brackets in vitro, and whether an interference by the brackets should be expected. The site of measurement was standardized on 30 extracted human molars with natural demineralization on smooth surfaces. Fluorescence was measured (Diagnodent) on prebonded, etched, bonded with stainless steel brackets, and debonded enamel. We found no statistically significant difference in fluorescence after etching. After bonding, the fluorescence decreased by a median value of 0.5 compared to the prebonded and etched enamel. After debonding, the fluorescence increased by a median value of 0.5 and 1 compared with the prebonded and bonded conditions, respectively. The lack of agreement between prebonded and bonded enamel values (limits +12.4/-12.6) was possibly due to the difficulty in finding the same spot without the bracket (coefficient of repeatability = 9.1-10.8). In vitro, demineralization around brackets can be measured by laser fluorescence, but clinical studies are necessary.

Diagnostic comparison of three groups of examiners using visual and laser fluorescence methods to detect occlusal caries in vitro

BACKGROUND

To evaluate the accuracy of the DIAGNOdent laser device (DD) for detecting occlusal fissure caries when used by three groups of examiners.

METHODS

Three final-year dental students (S), three General Dental Practitioners (G), and three Academic Clinicians (A) individually examined the non-cavitated occlusal surfaces of 25 extracted permanent molars using visual inspection (VI) then DD assessments. The presence of caries was confirmed following tooth sectioning. A cut-off limit of 30 was used for the DD to avoid over-treatment in a low caries-risk situation.

RESULTS

For VI, individual examiner sensitivity (caries correctly diagnosed) ranged from 53 to 86 per cent, and specificity (sound teeth correctly diagnosed) ranged from 76 to 95 per cent, with low Kappa agreements. Group S achieved the highest sensitivity (80 per cent) and Groups G and A achieved the highest specificities (88 per cent). For DD, individual examiner sensitivity ranged from 19DD, individual examiner sensificity ranged from 19 to 77 per cent, and specificity from 71 to 97 per cent, with generally moderate Kappa agreements. Group A achieved the highest (67 per cent) and Group G the lowest (44 per cent) sensitivities, and Group G achieved the highest specificity (94 per cent).

CONCLUSIONS

There were similar widely varying results for the two diagnostic methods and for the three groups of examiners. However, the relatively high sensitivities found with VI and specificities found with DD should avoid over-treatment in low caries-risk populations.

The Effectiveness of InGaAsP Diode Laser Radiation to Detect Subgingival Calculus as Compared to an Explorer

BACKGROUND

The aim of the present study was to compare the ability of the diode laser to detect residual calculus with that of an explorer.

METHODS

The root surface of 40 extracted human teeth, each partially covered with subgingival calculus, was instrumented with curets under simulated clinical conditions in a manikin. The samples were randomly assigned to two study groups. In group A, the root surface was treated with an explorer until it appeared free of mineralized deposits upon examination. The samples in group B were instrumented until the relative intensity of fluorescence as induced with diode laser radiation was below a threshold value of 5. The root surface of each sample was then examined for residual calculus using standardized digital images. The statistical analysis was performed with a non-paired t test at a level of significance of 5% (P < 0.05).

RESULTS

The root surface of single-rooted teeth showed residual calculus on 0.19 +/- 0.37 x 10(7) microm2 in the laser group and on 0.11 +/- 0.26 x 10(7) microm2 in the explorer group (P = 0.19). For multirooted teeth, the mean calculus-covered area was 0.50 +/- 0.48 x 10(7) microm2 for the teeth evaluated with an explorer and 0.27 +/- 0.43 x 10(7) microm2 for the diode laser group (P = 0.02).

CONCLUSION

The present findings indicate that the detection of subgingival calculus is significantly improved using 655 nm diode laser radiation compared to an explorer for molars but not for single-rooted teeth.

Effects of Drying Time and the Presence of Plaque on the in vitro Performance of Laser Fluorescence in Occlusal Caries of Primary Teeth

The diode laser fluorescence device was introduced to diagnose caries lesions in occlusal and smooth surfaces. Despite promising results, much variation has been found in the protocol of utilization. The goal of this study was to evaluate the influence of dental plaque and drying time on the laser fluorescence (DIAGNOdent) performance in occlusal sites of primary molars. For the drying time study, 63 suspected occlusal sites in primary molars were used. The same sites were evaluated in four different conditions: (1) moist teeth, (2) teeth dried for 3 s with a 3-in-1 syringe, (3) teeth dried for 15 s, and (4) dehydrated teeth. For the plaque experiment, we selected 28 occlusal sites. After the baseline laser fluorescence readings, plaque collected from children was placed on the suspected site. New laser fluorescence measurements were performed. For both studies, we compared the laser fluorescence values, as well as sensitivity, specificity, accuracy, and area under ROC curve. For different drying times, the more dehydrated the teeth, the higher the values. Nevertheless, the performance of the method did not change significantly, except for dehydrated teeth. In the presence of plaque, the laser fluorescence values were reduced, and the evaluated parameters were worse than with no plaque. In conclusion, the hydration state of the teeth did not change the results significantly, but the presence of plaque worsened the performance of the laser fluorescence method.

Lasers in dentistry

BACKGROUND

During the last two decades, much has been written in both the scientific literature and the popular press about lasers and their use in the dental office. Both soft- and hard-tissue applications have been discussed, including frenectomy, gingival contouring, caries removal and bleaching.

OVERVIEW

Almost one-third of patients surveyed by the American Dental Association in the late 1990s thought it was very important that their dentists have lasers, which could put pressure on dentists to invest in this tool to attract patients. The authors describe the different types of dental lasers and examine the science behind their applications in dentistry.

CONCLUSION AND CLINICAL IMPLICATIONS

Although lasers do have legitimate uses in dentistry, they do not take the place of any of the more conventional tools in the dentist's armamentarium. Before investing in a laser, dentists should fully understand the differences between the various types, including what the scientific literature says about their applications.

In vivo effectiveness of laser fluorescence compared to visual inspection and radiography for the detection of occlusal caries in primary teeth

The purpose of this study was to evaluate the in vivo effectiveness of laser fluorescence compared to visual inspection and radiography for the detection of occlusal caries in primary teeth. Fifty sites from 30 molars in 29 patients were selected and evaluated under standardized conditions by 2 previously trained examiners according to the 3 diagnostic methods. Histological examination served as gold standard after exfoliation or extraction. Values obtained for sensitivity, specificity and accuracy were 0.60, 0.90 and 0.73 for laser fluorescence, 0.82, 0.85 and 0.84 for visual inspection and 0.62, 0.73 and 0.67 for radiography, respectively. Considering only dentinal caries, values were 0.73, 0.95 and 0.90 for laser fluorescence, 0.61, 1.00 and 0.90 for visual inspection and 0.96, 0.81 and 0.85 for radiography, respectively. We conclude that for the detection of occlusal caries in primary molars laser fluorescence presents a similar accuracy when compared to visual inspection and radiography, although visual inspection showed better values for sensitivities for both enamel and dentin lesions.

Validity of a laser fluorescence system (DIAGNOdent) for detection of occlusal caries in third molars: an in vitro study

The aim of this study was to compare the validity of the measurements of the laser fluorescence device, KaVo DIAGNOdent, with the result of polarized light microscopy in the detection of occlusal fissure caries in extracted third molars. Ten impacted, surgically removed, and 25 extracted third molars with macroscopically intact occlusal surfaces were selected. The DIAGNOdent measurements of the occlusal test site were recorded by two observers at intervals of 2 days. The teeth were then sectioned at the specified test sites for histological examinations. Prepared specimens were evaluated under the polarized light microscopy and all images were scored with the caries classification of D1 (sound and fissure lesion in the half of the outer enamel), D2 (enamel decay) and D3 (dentin decay) level (gold standard). The kappa value for the inter-observer repeatability was calculated and the value 0.83 for the first measurements and 0.67 for the second measurement were obtained,respectively. Inter-observer correct classification percentages were 88.5 and 77.1 for the first and second measurements, respectively. The kappa value for intra-observer repeatability was 0.79 for the first observer and 0.75 for the second observer. Intra-observer correct classification percentage values were 85.7 and 82.8 for the first and second observer, respectively. Value of specificity for the detection of enamel caries at D1 level was 0.74 and sensitivity values at D2 and D3 levels were 0.66 and 1.00, respectively. The present study indicates that the DIAGNOdent provides not only almost perfect agreement but also sufficient repeatability at D1, D2, D3 levels and better specificity at D1 level as well as lower sensitivity at D2 level and excellent sensitivity at D3 level.

Evaluation of the Effectiveness of Laser Fluorescence in Monitoring in vitro Remineralization of Incipient Caries Lesions in Primary Teeth

The purpose of this investigation was to examine the effectiveness of laser fluorescence for monitoring in vitro remineralization of caries lesions. Seventeen natural enamel lesions in primary molars were each cut into two parts. One part was exposed, at room temperature, to a remineralizing solution (experimental) and the other part to water (control) for 28 days. Laser fluorescence readings were taken at the beginning of the experiment and during the experiment. At the end of the experiment, lesion depth in the experimental halves was significantly less than in the control halves (p < 0.01), suggesting that remineralization had occurred. However, the laser fluorescence readings showed no statistically significant changes during the experiment, either in the experimental or control halves. We conclude that laser fluorescence was not able to detect in vitro remineralization of natural incipient caries lesions of primary teeth.

Comparative Study of Carious Dentin Removal by Er,Cr:YSGG Laser and Carisolv

OBJECTIVE

The present study aimed to compare carious dentin removal by air turbine, Carisolv and erbium,chromium:yttrium,scandium,gallium,garnet (Er,Cr:YSGG) laser, and examine morphological changes before and after these caries removal techniques under light microscopy and scanning electron microscopy (SEM).

BACKGROUND DATA

Although there have been numerous studies on removing caries by Er,Cr:YSGG laser, none has compared Er,Cr:YSGG laser and Carisolv, or reported on the usage of DIAGNOdent as a diagnostic tool particularly for advanced caries in in vitro experiments.

MATERIALS AND METHODS

Sixty extracted human teeth diagnosed as advanced caries were divided into three groups based on the treatment received, namely air turbine, Carisolv, and Er,Cr:YSGG laser groups. Each group was sub-divided into two in order to examine the results with or without finishing using nylon brush, 15% ethylene diamine tetraacetic acid (EDTA) or low-power laser, respectively. After evaluation by DIAGNOdent, specimens were observed under light microscopy or SEM.

RESULTS

Light microscopic observations varied considerably in the three treatment groups. SEM revealed that the surfaces treated by air turbine were very smooth, but with substantial debris. The Carisolv group exhibited a very rough surface with a thick smear layer, while the Er,Cr:YSGG group demonstrated smooth undulations with little smear layer and debris. Among the finishing techniques, the laser group demonstrated the best efficiency. DIAGNOdent scores supported the results of light microscopy.

CONCLUSION

These results suggest that caries removal by Er,Cr:YSGG laser is very effective even without finishing and DIAGNOdent is useful for diagnosing advanced caries in in vitro experiments.

The current status of laser applications in dentistry

A range of lasers is now available for use in dentistry. This paper summarizes key current and emerging applications for lasers in clinical practice. A major diagnostic application of low power lasers is the detection of caries, using fluorescence elicited from hydroxyapatite or from bacterial by-products. Laser fluorescence is an effective method for detecting and quantifying incipient occlusal and cervical carious lesions, and with further refinement could be used in the same manner for proximal lesions. Photoactivated dye techniques have been developed which use low power lasers to elicit a photochemical reaction. Photoactivated dye techniques can be used to disinfect root canals, periodontal pockets, cavity preparations and sites of peri-implantitis. Using similar principles, more powerful lasers can be used for photodynamic therapy in the treatment of malignancies of the oral mucosa. Laser-driven photochemical reactions can also be used for tooth whitening. In combination with fluoride, laser irradiation can improve the resistance of tooth structure to demineralization, and this application is of particular benefit for susceptible sites in high caries risk patients. Laser technology for caries removal, cavity preparation and soft tissue surgery is at a high state of refinement, having had several decades of development up to the present time. Used in conjunction with or as a replacement for traditional methods, it is expected that specific laser technologies will become an essential component of contemporary dental practice over the next decade.

Microtensile bond strength of total-etch and self-etching adhesives to caries-affected dentine

OBJECTIVES

To evaluate the microtensile bond strength of total-etch or self-etch adhesives to caries-affected versus normal dentine, and to correlate these bond strengths with DIAGNOdent laser fluorescence and Knoop microhardness (KH) measurements of the substrates.

METHODS

Extracted carious human molars were ground to expose flat surfaces where the caries lesion was surrounded by normal dentine. Surfaces were bonded with either Prime & Bond NT, Scotchbond 1, Clearfil SE Bond or Prompt L-Pop, according to manufacturers' recommendations. A crown was built up using resin composite (Tetric Ceram). After storage in water (37 degrees C, 24 h), teeth were vertically serially sectioned into 0.7 mm thick slabs and trimmed to yield 1 mm(2) test area that contained either caries-affected or normal dentine. Samples were tested in tension in an Instron machine at 1 mm/min. The quality of the dentine just beneath each fractured specimen was measured by laser fluorescence and KH.

RESULTS

Total-etch adhesives yielded higher bond strengths than self-etching systems. Significantly lower results were obtained with Prompt L-Pop. All the adhesives attained higher strengths in normal than in caries-affected dentine, but the differences were only significant for Prime & Bond NT and Clearfil SE Bond. Higher laser fluorescence values and lower KH (p<0.001) were recorded in caries-affected dentine compared to normal dentine.

CONCLUSIONS

The total-etch adhesives evaluated produced higher bond strengths to normal and caries-affected dentine than self-etching systems. Laser fluorescence measurements discriminated caries-affected dentine from normal dentine, and were strongly correlated with KH. However, laser fluorescence and KH did not permit high correlations with resin-dentine bond strengths in caries-affected dentine.

Diagnosis of approximal caries: bite-wing radiology versus the Ultrasound Caries Detector. An in vitro study

OBJECTIVE

We sought to examine the validity, sensitivity, and specificity of bite-wing radiographs and a high-frequency sound wave device (the Ultrasound Caries Detector) used to detect caries on contacting approximal surfaces.

METHODS

A total of 36 extracted premolars and molars were first visually examined for the presence of caries; then a probe was used. Twelve models were prepared, each containing 3 teeth with 2 approximal surfaces and 2 contacted surfaces (of adjacent teeth). Bite-wing radiographs were taken and evaluated for proximal caries lesions. A high-frequency sound wave (ultrasound) device called the Ultrasound Caries Detector was also used to detect caries. Examinations were repeated after 1 week. Teeth were then sectioned and viewed under a stereomicroscope at 20x magnification, with which the true interproximal caries diagnosis was validated. The receiver operating characteristic curves were computed to establish the accuracy of the observer data.

RESULTS

The efficacy of the ultrasound diagnostic device for cavitated carious lesion detection was assessed by determining its specificity and sensitivity, 1.0 for each, in comparison with those of bite-wing radiography, 0.92 and 0.90, respectively (P <.001). The mean receiver operating characteristic value for the area under the curve was 0.934 with bite-wing radiography and 1 with the ultrasound diagnostic device.

CONCLUSIONS

Under in vitro conditions, the ultrasound diagnostic device had a higher sensitivity and specificity, in terms of the detection of approximal carious lesions, than bite-wing radiographs.

A systematic review of the performance of methods for identifying carious lesions

This systematic review evaluates evidence describing histologically validated performance of methods for identifying carious lesions. A search identified 1,407 articles, of which 39 were included that described 126 assessment of visual, visual/tactile, radiographic (film and digital), fiber optic transillumination, electrical conductance, and laser fluorescence methods. A subsequent update added four studies contributing 10 assessments. The strength of the evidence was judged to be poor for all applications, signifying that the available information is insufficient to support generalizable estimates of the sensitivity and specificity of any given application of a diagnostic method. The literature is problematic with respect to complete reporting of methods, variations in histological validation methods, the small number of in vivo studies, selection of teeth, small numbers of examiners, and other factors threatening both internal and external validity. Future research must address these problems as well as expand the range of assessments to include primary teeth and root surfaces.

In vitro study of caries detection through sound dentin using a laser fluorescence device, DIAGNOdent

The objective of this study was to investigate the feasibility of proximal surface caries detection using a laser fluorescence device, DIAGNOdent, through the sound dentin surrounding the cavity wall after removal of occlusal caries. Extracted sound human molars were ground to prepare horizontal and vertical dentin plates 1.4 mm thick. Extracted carious human molars were reduced in thickness horizontally from the occlusal surfaces until exposure of the dentin caries. The dentin plate was placed on the carious tooth. Before and after gradual thinning of the dentin plate from approximately 1.4 mm to 0.2 mm thick, the dentin caries was measured 10 times through the plate by the laser fluorescence device with a cone-shaped tip or a broad tip. When the dentin plate was reduced to less than 0.3 mm thick (using a combination of a horizontal plate and cone-shaped tip) or 0.2 mm thick (using the other combinations), the values measured with the laser fluorescence device were significantly larger than the values before reducing the thickness of the dentin. Based on these results, the device offers potential use as one of the screening tests for proximal surface caries detection through sound dentin when the sound dentin between tip and caries is thin.

An in vitro comparison of a combined FOTI/visual examination of occlusal caries with other caries diagnostic methods and the effect of stain on their diagnostic performance

The aims of this in vitro study were to compare the combination of FOTI and visual inspection to other diagnostic methods for the detection and evaluation of the depth of occlusal caries and assess the effect of stain on diagnostic performance. Five diagnostic methods (combined FOTI/Visual (CFV), Visual, FOTI, DIAGNOdent and Electrical Caries Monitor) were considered. Histological validation was performed in the 152 occlusal molar sites (111 teeth) using 350-microm sections and a stereomicroscope. The rank correlation coefficients with histology ranged from 0.42 (DIAGNOdent) to 0.66 (CFV). The area under the ROC curves (AUC) for enamel lesions ranged from 0.82 (ECM) to 0.88 (CFV) and from 0.81 (DIAGNOdent) to 0.91 (CFV) for dentine lesions. The AUC at the dentine level for CFV and FOTI were similar (p > 0.05), but the AUC for CFV was significantly greater than for visual (p < 0.001), DIAGNOdent (p = 0.005) and the ECM (p = 0.04). FOTI was found to be particularly useful for the detection of dentine lesions. The exclusion of stain and brown spot lesions improved performance for all methods. It is concluded that CFV is useful for the determination of occlusal lesion depth and that in the presence of stain and brown spot lesions different cut-off points may be required for the ECM and DIAGNOdent to identify dentine lesions.

Clinical study of the use of the laser fluorescence device DIAGNOdent for detection of occlusal caries in children

Diagnosis of non-cavitated occlusal caries is generally considered problematic. The aim of this study was to evaluate the utility of the laser fluorescence device DIAGNOdent as part of routine dental check-ups in children. A total of 613 occlusal surfaces on permanent molars and 436 surfaces on primary molars in children aged 7-8 (n = 55) and 13-14 years (n = 54) were examined visually, using DIAGNOdent and for most 13- to 14-year-olds also using radiographs. The teeth were not cleaned professionally before examination. To provide a gold standard for carious teeth, the depth of the caries lesion was determined in those lesions that were judged visually to need opening by drilling (51 teeth). The higher the visual score, the higher were the mean DIAGNOdent values, but in each visual category the variation among values was large. The presence of a clear sealant did not affect DIAGNOdent measurements. The values for permanent and primary molars differed slightly. For permanent teeth, Youden's index value was highest (60%) at a cut-off value of 30, which indicates that the overall performance for DIAGNOdent in detecting dentinal caries was best at this point. Using this cut-off, sensitivity was 92% and specificity 69% with visual examination for validation, while sensitivity was 92% and specificity 82% with validation by fissure opening. Of the three methods, radiographic examination was the least accurate. In routine dental check-ups of children, DIAGNOdent appears to be useful as an adjunct to visual examination.

Performance of conventional and new methods for the detection of occlusal caries in deciduous teeth

The aim of this study was to compare, in vitro, the performance of different conventional diagnostic techniques with the laser-based device, DIAGNOdent, for diagnosis of occlusal caries in deciduous teeth. 95 deciduous teeth with macroscopically intact occlusal surfaces were selected. All teeth were assessed by the following techniques: visual inspection (VI), visual inspection with magnification (VIM), visual inspection combined with light pressure probing (VIP), bitewing radiography (BW) and the DIAGNOdent (DD). Caries extension was assessed by histology. DIAGNOdent showed, in comparison with the conventional clinical methods, a significantly improved ability (p < 0.05) to detect dentinal lesions (D(3) or D(4)) in deciduous teeth and an overall performance similar to that obtained in previous studies on permanent teeth. There was no statistically significant difference between VIM and DD in detecting caries confined to enamel (D(2)). DD performed better at D(2) level than the other methods. The intraexaminer kappa scores for DIAGNOdent were 0.76-0.86 (D(2)) and 0.77-0.85 (D(3)), respectively. It was concluded that DIAGNOdent could be used as an additional tool in the detection of occlusal caries in deciduous teeth and its good reproducibility should enable the laser device to monitor the caries process over time.

Occlusal caries detection and quantification by DIAGNOdent and Electronic Caries Monitor: in vitro comparison

The Electronic Caries Monitor (ECM) and the recently introduced laser-based KaVo DIAGNOdent have been developed as clinical diagnostic aids in the detection and quantification of occlusal carious lesions. The aim of this in vitro study was to compare their reproducibility and validity. The ability of DIAGNOdent to retrieve sites of occlusal carious lesions without reference to photographs or drawings from previous assessments was also tested. The material comprised 87 premolar teeth: the occlusal surfaces were sound or exhibited non-cavity carious lesions of varying severity. All were photographed and measured by DIAGNOdent and ECM on 2 occasions, 2 weeks apart. The teeth were then sectioned into 300 microm thick slices. Two observers independently classified the sections according to the histopathology, into 5 categories, ranging from sound to dentinal caries in the inner part of the dentin. Statistical analysis comprised intra-class correlation coefficients (ICC) to test reproducibility and regression analysis of validity. Sensitivity and specificity were also calculated for detection of D3 lesions for both devices. DIAGNOdent recorded maximum readings at identical sites on both occasions in 89% of the teeth. The ICC for readings on 2 separate occasions was 0.97 for DIAGNOdent and 0.71 for ECM. The correlations with histology were r = 0.93 and 0.83, for DIAGNOdent and ECM, respectively. For detection of D3 lesions, the sensitivity and specificity were 0.8 and 1 for DIAGNOdent and 0.75 and 0.88 for ECM. In this in vitro study, DIAGNOdent was superior to ECM for occlusal caries detection.

Imaging caries lesions and lesion progression with polarization sensitive optical coherence tomography

New diagnostic tools are needed for the characterization of dental caries in the early stages of development. If carious lesions are detected early enough, they can be arrested without the need for surgical intervention. The objective of this study was to demonstrate that polarization sensitive optical coherence tomography (PS-OCT) can be used for the imaging of early caries lesions and for the monitoring of lesion progression over time. High-resolution polarization resolved images were acquired of natural caries lesions and simulated caries lesions of varying severity created over time periods of 1 to 14 days. Linearly polarized light was incident on the tooth samples and the reflected intensity in both orthogonal polarizations was measured. PS-OCT was invaluable for removing the confounding influence of surface reflections and native birefringence necessary for the enhanced resolution of the surface structure of caries lesions. This study demonstrated that PS-OCT is well suited for the imaging of interproximal and occlusal caries, early root caries, and for imaging decay under composite fillings. Longitudinal measurements of the reflected light intensity in the orthogonal polarization state from the area of simulated caries lesions linearly correlated with the square root of time of demineralization indicating that PS-OCT is well suited for monitoring changes in enamel mineralization over time.

Intra- and interexaminer variability and validity of laser fluorescence and electrical resistance readings on root surface lesions

The purpose of this study was to investigate the validity and reproducibility of laser fluorescence and electrical resistance readings on root carious lesions. One hundred and three freshly extracted human teeth with various forms of natural root caries were investigated by 6 operators using the laser fluorescence device DIAGNOdent (DD) and the Electronic Caries Monitor (ECM III). As a reference, a caries-free root area of each tooth was also examined. Specimens were classified as to colour, surface texture and cavitation depth. Teeth were sectioned through the centre of the lesion and prepared for polarising light microscopy. Histological depth of the lesions was defined as the distance between the surface and zone of translucency. Depths ranged from 0.1 to 3.1 mm. Statistical analysis of the interexaminer reproducibility revealed a significant correlation (Kendall's W) for DD measurements of 0.85 and 0.76 for ECM readings. Moderate correlation between the histological depth and DD (r(s) = 0.45) or ECM scores (r(s) = -0.48) could be demonstrated. Electrical resistance readings revealed a positive correlation (r(s) = 0.43) with the thickness of the remaining dentine, whereas this was negative for laser fluorescence readings (r(s) = -0.43). However, scatter plots suggested that most lesions had very low resistance. This investigation suggests that laser fluorescence and electrical conductance measurements can be obtained reproducibly by different operators and correlate moderately with histological lesion depth and remaining thickness of the dentine bridge.

Subgingival calculus detection with fluorescence induced by 655 nm InGaAsP diode laser radiation

BACKGROUND

It has been suggested that the 655 nm InGaAsP diode laser radiation can induce considerably higher amounts of fluorescence in subgingival calculus than in cementum. This in vitro study evaluated the use of fluorescence induced by the diode laser radiation for the detection of subgingival calculus.

METHODS

The study sample consisted of 30 extracted molars, premolars, canines, and incisors. The root surface of each sample was partially covered with subgingival calculus. The source of laser radiation was an InGaAsP diode laser emitting visible radiation at a wavelength of 655 nm. The fluorescent radiation reflected from the cementum and calculus was detected by a photoelectric cell integrated within the diagnostic system. The samples were randomly assigned to 3 experimental groups of 10 teeth each for detection of calculus in various media. Specifically, the fluorescence was determined in air (group A), in electrolytic salt solution (group B), and in blood (group C). For each sample, the intensity of the fluorescent light was evaluated separately for cementum and calculus in triplicate measurements. The statistical analysis was performed using a t test at a level of significance of 5% (P<0.05).

RESULTS

The intensities of fluorescence radiation emitted by cementum were 0.4 (+/-0.51) in air, 0.4 (+/-0.51) in electrolytic solution, and 2.13 (+/-0.59) in blood. For calculus, the relative intensities of fluorescence radiation were 54.1 (+/-29.09) in air, 60.77 (+/-28.35) in electrolytic salt solution, and 39.63 (+/-29.79) in blood. The differences in fluorescence between cementum and calculus within each experimental unit were significant (group A: P= 0.0002, group B: P= 0.0001, group C: P= 0.031). The intensity of fluorescence in calculus was also significantly different between the 3 experimental groups.

CONCLUSION

The present study indicates that subgingival calculus can be reliably detected on extracted teeth using laser fluorescence induced by the 655 nm diode-laser radiation. In vivo studies are necessary to evaluate the clinical utility of this procedure.

Reliability and validity issues of laser fluorescence measurements in occlusal caries diagnosis

OBJECTIVES

Recently, a device for detecting occlusal caries lesions based on laser fluorescence measurements (DIAGNOdent) has been introduced. The reliability (reproducibility) and validity of this laser-fluorescence device were investigated.

METHODS

In the in vitro part of the study, 49 permanent molars were measured by two observers using two DIAGNOdent devices. In addition, visual inspection was performed. The teeth were sectioned to measure the actual depth and area of the caries lesions. In the in vivo part of the study, 45 sites at the occlusal surfaces of permanent molar teeth in 13 patients were measured by two observers using two DIAGNOdent devices, manufactured in two successive years.

RESULTS

The reliability of both DIAGNOdent devices expressed in the intraclass correlation coefficient (ICC=0.90 for observer 1, and 0.88 for observer 2) was high, and so was the interobserver reliability (ICC=0.85 for the 1998-device, ICC=0.90 for the 1999-device). The correlation between DIAGNOdent measurements and the actual depth of the caries lesions was lower than that of visual inspection by one observer, yet higher than that of a second observer. The specificities of visual inspection (0.94 and 0.88) were higher than those of the DIAGNOdent devices, whereas the sensitivities of the DIAGNOdent devices (0.93-1.00) exceeded those of visual inspection The validity of the DIAGNOdent, expressed as the area under the receiver operating characteristic curve, was not statistically significantly different from that of visual inspection (P>0.05). The DIAGNOdent measurements showed a higher association with the enamel part of the caries lesion than with the dentinal part.

CONCLUSIONS

The DIAGNOdent is suitable for monitoring small caries lesions. Because of the high reproducibility of DIAGNOdent devices produced in successive years, a DIAGNOdent device may be replaced by a new one. Due to the higher specificity, visual inspection should be preferred to diagnose occlusal caries lesions in populations with a low caries prevalence.

Validity and reproducibility of a laser fluorescence system for detecting the activity of white-spot lesions on free smooth surfaces in vivo

The aim of the study was to determine the reproducibility and validity of DIAGNOdent in detecting active and arrested caries lesions on free smooth surfaces. Volunteers were selected from state schools of Piracicaba, São Paulo, Brazil. Overall, 220 lesions were clinically examined. Two specially trained ('calibrated') examiners performed both clinical and laser evaluations independently, and after a 1-week interval, the examinations were repeated. The intra-examiner agreement for the laser evaluation was substantial (kappa(ex1) = 0.79, kappa(ex2) = 0.71). There was almost perfect agreement between the two examiners for the clinical examination (kappa(ex1) = 0.95, kappa(ex2) = 0.85). The inter-examiner agreement showed substantial reproducibility (kappa = 0.77) for the laser examination and almost perfect agreement (kappa = 0.85) for the clinical evaluation. The validation criterion was the clinical examination of white spots, recorded as active or arrested. The sensitivity was 0.72 and the specificity was 0.73, which indicates that the DIAGNOdent was a good auxiliary method for detecting incipient caries lesions on free smooth surfaces. The utilization of both methods can improve the efficacy of caries diagnosis.

Comparison between visual examination and a laser fluorescence system for in vivo diagnosis of occlusal caries

This study compared a laser fluorescence (LF) system (DIAGNOdent) with a visual caries scoring system for in vivo detection and diagnosis of occlusal caries under the conditions of an epidemiological study, in 132 mandibular and 38 maxillary first permanent molars in 170 children (mean age: 6.85 +/- 0.58 years). The teeth were cleaned and occlusal caries status in a selected investigation site recorded using both visual and LF systems. The LF readings were interpreted both according to the cut-off points recommended by the manufacturers and those based on laboratory research with histological validation. The percentage agreement of the LF and visual scoring system was better using the cut-off limits recommended by the manufacturer. Histological validation was not possible in this clinical study, but it appeared that either the LF method was overscoring some lesions or the visual method was underscoring them. Since the LF instrument cannot be expected to differentiate caries from hypomineralisation, it should probably be used as an adjunct to a clinical examination.

Detection of occlusal caries under sealants by use of a laser fluorescence system

OBJECTIVE

In recent years, various dental caries diagnosis systems, including digital radiography, light fluorescence, and lasers, have been developed. The aim of this study was to evaluate the new laser fluorescence system known as DIAGNOdent for its ability to detect occlusal caries under sealants.

BACKGROUND DATA

Fluorescence induced by laser light for early diagnosis of enamel caries was introduced by Bjelkhagen et al. in 1982, but these systems were difficult to use in the oral cavity. Recently, DIAGNOdent has been shown to have a higher diagnostic validity for the detection and quantification of caries lesions than the electronic caries monitor and to have a higher reproducibility for measurements, according to work by Lussi et al. in 1999. The laser diagnosis system is able to indicate the value of reflected fluorescence on a digital display. This value is associated with the carious progression.

METHODS

Thirty-two extracted permanent premolars and molars that had occlusal dental caries were used in this study. The reflected fluorescence was measured by use of DIAGNOdent at the occlusal surface of the tooth before and after chemical irrigation, acid etching, and application of a light-cured fluoride releasing sealant. The measurements were two or three points per experimental tooth. A total of 53 points on the experimental teeth was evaluated.

RESULTS

The mean reflected fluorescence value was significantly decreased by chemical irrigation; however, no difference was noted between the value before and the salve after acid etching. These teeth were divided into three groups: clear, red, and white as tooth color sealants of the tooth. The reflected fluorescence value before and after sealants was tested for statistical significance. The diagnosis of caries under sealants was up to 10 of reflected fluorescence value in the study. Clear and red sealants were used to reveal caries under sealants using visual inspection, and all sealants groups achieved 90% of reflected fluorescence value after sealants application. However, the white sealants did not reveal caries through visual inspection. The detection ability of caries under white sealants was 53.5% (n = 23/42).

CONCLUSIONS

This laser diagnosis system makes it easy to detect the existence of caries under a pit and fissure sealant during a routine check-up.

How to measure the effects of fluoride treatments in clinical trials? Assessment: modern versus traditional methods

In recent years there has been a pronounced change in the epidemiology and disease pattern of dental caries. In the current context, traditional methods of caries assessment, discriminating lesions at cavitation, are clinically inappropriate, and obsolete for research requiring detection of a very early phase of mineral loss. Modern prospective caries studies require sensitive methods permitting the measurement of small changes in tooth mineral content, and objective, quantitative measurements of such changes are now possible in a single caries lesion. For longitudinal studies there are noninvasive methods for assessment of new lesions as well as quantitative changes (progression or regression) in existing lesions. Among as yet unresolved issues are improved methods to assess the current activity of a lesion, methods for detection and quantification of secondary caries and root caries, calibration of methodologies between different research institutes, and methods capable of assessment of the whole continuum in the development of a caries lesion, from initial loss of mineral to cavitation.