The possibility of detecting subgingival calculus by laser-fluorescence in vitro

Effectiveness of a 655-nm InGaAsP diode laser to detect subgingival calculus in patients with periodontal disease

BACKGROUND

Previous in vitro studies have proven laser fluorescence measurement using a 655-nm Indium Gallium Arsenide Phosphide (InGaAsP) based diode laser radiation to be a useful tool to detect subgingival calculus. The aim of this prospective study was to evaluate the 655-nm InGaAsP diode laser in detecting subgingival calculus in patients with periodontal disease compared with photographic assessment during periodontal surgery.

METHODS

Twelve patients (six women, six men) aged between 21 and 75 years with periodontitis scheduled for periodontal surgery were included in this prospective study. All laser fluorescence measurements were made before periodontal surgery. Intraoperatively a mucoperiostal flap was performed, subgingival calculus was visualized, and photographic images were taken. The presence of calculus was recorded for each evaluated site.

RESULTS

A total of 115 tooth surface sites of 32 teeth from the 12 patients were evaluated before (laser) and during surgery (image). Compared with image evaluation the laser assessment showed a sensitivity of 0.70 (CI_{0 .025} 0.53 to CI_0.975 0.83) and a specificity of 0.97 (CI_0.025 0.85 to CI_0.975 0.99). The overall probability to correctly detect subgingival calculus with the laser (accuracy) was 0.82 (CI_0.025 0.74 to CI_0.975 0.88).

CONCLUSIONS

The 655-nm diode laser was able to detect subgingival calculus. Hence, the 655 nm diode laser may be used as an additional tool for calculus detection in non-surgical periodontal therapy.

Photonic Therapy in Periodontal Diseases an Overview with Appraisal of the Literature and Reasoned Treatment Recommendations

Recent reviews and meta-analyses of the literature over the past quarter-century have failed to provide enough evidence to prove or disprove the actual utility of photonic therapy in periodontitis, alone or adjunctive to conventional approaches. This apparent paradox has been explained by the many physical, molecular, biological, anatomical, and technical variables of photonic treatments, which can differ in light-emitting devices (laser or LED), wavelengths, irradiation power and modes, clinical objectives, follow-up times, disease grading, and assessment methods. This multi-faceted, controversial scenario has led practitioners to underestimate the actual potential of photonic therapy in periodontal diseases. In this critical appraisal of the literature, we have briefly summarized the main photonic therapies and instruments used in Periodontology, highlighting their main characteristics and limitations. Then, we have tried to identify and discuss the key methodological issues which can have an impact on the outcome of photonic therapies. Our main goal was to identify the best parameters, settings, and methodologies to perform effective periodontal photonic treatments and to extrapolate some recommendations for clinical use. Should these recommendations find a consensus among periodontologists and be adopted in future clinical studies, they will hopefully contribute to dissipate the present confusion and uncertainty on this complex matter.

Image-Guided Ablation of Dental Calculus From Root Surfaces Using a DPSS Er:YAG Laser

BACKGROUND AND OBJECTIVES

Recent studies have demonstrated that near-infrared (IR) imaging can be used to acquire high-contrast images of root caries and calculus on the root surfaces of extracted teeth at wavelengths longer than 1450 nm. The purpose of this study was to determine if image-guided laser ablation can be used to selectively remove calculus from tooth surfaces with minimal damage to the underlying sound cementum and dentin.

MATERIALS AND METHODS

In this study, sequential near-IR images at 1500-1700 nm were used to guide a diode-pumped (DPSS) Er:YAG laser for the removal of calculus from the root surfaces of 10 extracted teeth. The selectivity of removal was assessed using digital microscopy, optical coherence tomography, and surface profilometry.

RESULTS

Calculus was removed rapidly with minimal damage to the underlying sound cementum and dentin. Image-guided ablation achieved high-selectivity, the mean volume of calculus removal was more than 27 times higher than the mean loss of cementum.

CONCLUSIONS

We have demonstrated that near-IR image-guided laser ablation can be used for the selective removal of calculus from root surfaces ex vivo. Additionally, we have demonstrated that a diode-pumped solid-state Er:YAG laser is well suited for selective removal. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

Evaluation of calculus imaging on root surfaces by spectral-domain optical coherence tomography

OBJECTIVE

The aim of this in vitro study was to evaluate the ability of optical coherence tomography (OCT) to display calculus on root surfaces.

MATERIAL AND METHODS

Ten teeth with calculus on the root surface were embedded in resin, omitting the root surface. A region of interest (ROI) was marked by small drill holes coronally and apically of the calculus and imaged by spectral-domain optical coherence tomography ([SD OCT], Telesto SP5, centre wavelength 1310 nm) and light microscopy (LM). To evaluate the impact of different fluids on calculus visualisation, using OCT, root surfaces were covered by a layer of NaCl and blood and displayed by OCT. Subsequently, teeth were completely covered with resin and sectioned for histological evaluation. Within the ROI, lengths of root surface and calculus were measured by LM and OCT, and the ratio [%] was calculated. In addition, at three sites of each ROI, agreement of presence and length of calculus was evaluated. Both methods were compared using Pearson's correlation.

RESULTS

Regarding the presence of calculus, agreement between LM and OCT was strong (κ_i = 0.783, p = 0.033), and measurements regarding the length of the calculus were strongly correlated (r_i >0.906; p_i <0.001). However, the values differed for dry (p = 0.023) and NaCl-covered root surfaces (p = 0.035).

CONCLUSION

Calculus on the root surface can be displayed by SD-OCT, which therefore may be suited as imaging technology for subgingival calculus in periodontal pockets.

In vitro performance of DIAGNOdent laser fluorescence device for dental calculus detection on human tooth root surfaces

OBJECTIVE

This study assessed the reproducibility of a red diode laser device, and its capability to detect dental calculus in vitro on human tooth root surfaces.

MATERIAL AND METHODS

On each of 50 extracted teeth, a calculus-positive and calculus-free root surface was evaluated by two independent examiners with a low-power indium gallium arsenide phosphide diode laser (DIAGNOdent) fitted with a periodontal probe-like sapphire tip and emitting visible red light at 655 nm wavelength. Laser autofluorescence intensity readings of examined root surfaces were scored on a 0-99 scale, with duplicate assessments performed using the laser probe tip directed both perpendicular and parallel to evaluated tooth root surfaces. Pearson correlation coefficients of untransformed measurements, and kappa analysis of data dichotomized with a >40 autofluorescence intensity threshold, were calculated to assess intra- and inter-examiner reproducibility of the laser device. Mean autofluorescence intensity scores of calculus-positive and calculus-free root surfaces were evaluated with the Student's t-test.

RESULTS

Excellent intra- and inter-examiner reproducibility was found for DIAGNOdent laser autofluorescence intensity measurements, with Pearson correlation coefficients above 94%, and kappa values ranging between 0.96 and 1.0, for duplicate readings taken with both laser probe tip orientations. Significantly higher autofluorescence intensity values were measured when the laser probe tip was directed perpendicular, rather than parallel, to tooth root surfaces. However, calculus-positive roots, particularly with calculus in markedly-raised ledges, yielded significantly greater mean DIAGNOdent laser autofluorescence intensity scores than calculus-free surfaces, regardless of probe tip orientation. DIAGNOdent autofluorescence intensity values >40 exhibited a stronger association with calculus (36.6 odds ratio) then measurements of ≥5 (20.1 odds ratio) when the laser probe tip was advanced parallel to root surfaces.

CONCLUSIONS

Excellent intra- and inter-examiner reproducibility of autofluorescence intensity measurements was obtained with the DIAGNOdent laser fluorescence device on human tooth roots. Calculus-positive root surfaces exhibited significantly greater DIAGNOdent laser autofluorescence than calculus-free tooth roots, even with the laser probe tip directed parallel to root surfaces. These findings provide further in vitro validation of the potential utility of a DIAGNOdent laser fluorescence device for identifying dental calculus on human tooth root surfaces.

Analysis of root surface properties by fluorescence/Raman intensity ratio

The aim of this study is to evaluate the existence of residual calculus on root surfaces by determining the fluorescence/Raman intensity ratio. Thirty-two extracted human teeth, partially covered with calculus on the root surface, were evaluated by using a portable Raman spectrophotometer, and a 785-nm, 100-mW laser was applied for fluorescence/Raman excitation. The collected spectra were normalized to the hydroxyapatite Raman band intensity at 960 cm⁻¹. Raman spectra were recorded from the same point after changing the focal distance of the laser and the target radiating angle. In seven teeth, the condition of calculus, cementum, and dentin were evaluated. In 25 teeth, we determined the fluorescence/Raman intensity ratio following three strokes of debridement. Raman spectra collected from the dentin, cementum, and calculus were different. After normalization, spectra values were constant. The fluorescence/Raman intensity ratio of calculus region showed significant differences compared to the cementum and dentin (p < 0.05). The fluorescence/Raman intensity ratio decreased with calculus debridement. For this analysis, the delta value was defined as the difference between the values before and after three strokes, with the final 2 delta values close to zero, indicating a gradual asymptotic curve and the change in intensity ratio approximating that of individual constants. Fluorescence/Raman intensity ratio was effectively used to cancel the angle- and distance-dependent fluctuations of fluorescence collection efficiency during measurement. Changes in the fluorescence/Raman intensity ratio near zero suggested that cementum or dentin was exposed, and calculus removed.

Dental calculus detection using the VistaCam

The VistaCam® intra-oral camera system (Dürr Dental, Bietigheim-Bissingen, Germany) is a fluorescence system using light emitting diodes that produce a 405-nm violet light. This wavelength has potential application for detection of dental calculus based on red emissions from porphyrin molecules. This study assessed the digital scores obtained for both supragingival and subgingival calculus on 60 extracted teeth and compared these with lesions of dental caries. It has also examined the effect of saliva and blood on the fluorescence readings for dental calculus. VistaCam fluorescence scores for both supragingival (1.7-3.3) and subgingival calculus (1.3-2.4) were higher than those for sound root surfaces (0.9-1.1) and dental caries (0.9-2.2) (p < .05). The readings for calculus samples were not affected by the presence of saliva or blood. These results suggest that the use of violet light fluorescence could be a possible adjunct to clinical examination for deposits of dental calculus.

DIAGNOdent Pen versus tactile sense for detection of subgingival calculus: an in vitro study

The objective of this study is to compare the performance of the DIAGNOdent laser fluorescence (LF) Pen to conventional periodontal probing for detection of subgingival calculus under defined laboratory conditions. Extracted teeth with various levels of subgingival deposits of calculus were mounted anatomically in stone casts, and an impression material was used to replicate periodontal soft tissues. The casts were examined for the presence of subgingival calculus at eight surfaces per tooth (240 sites) using LF and a periodontal probe. Sites were rescored after 1 and 3 weeks. Direct imaging of the root surfaces under magnification was the gold standard. As a result, for an experienced operator, LF was more accurate than tactile assessment (across all sites, 84.0% vs. 59.8%). The performance difference was greater for multi-rooted teeth (85.8% vs. 56.9%) than single-rooted teeth (77.2% vs. 66.7%). The performance of LF in this laboratory trial was influenced strongly by clinician skill and experience. When used by an experienced operator, LF was more sensitive (75.1% vs. 69.2%), specific (92.6% vs. 86.3%), and accurate (84% vs. 77.9%) than for an inexperienced operator. In conclusion, under the defined laboratory conditions used, LF had better performance than tactile examination, particularly for multi-rooted teeth. This method may have value clinically as an adjunct for detecting subgingival deposits of calculus in clinical practice. The usefulness of the method improves with operator experience.

Effect of Different Contact Materials on Approximal Caries Detection by Laser Fluorescence and Light-Emitting Diode Devices

OBJECTIVE

The aim of this in vitro study was to investigate the influence of the adjacent tooth surface on pen type laser fluorescence (LFpen) and light-emitting diode (LED) device readings in detecting approximal caries lesions in permanent teeth.

BACKGROUND DATA

Early detection of noncavitated dental caries is important, because disease progression can be easily halted at this stage with certain applications, such as fluoride therapy, antibacterial therapy, dietary changes, or low-intensity laser irradiation.

MATERIALS AND METHODS

A total of 87 permanent molars with 156 approximal surfaces were assessed with LED- and LF-based devices in contact with sound tooth surfaces (the control group) as well as approximal amalgam, composite, zirconia, and full ceramic restorations. All teeth were assessed once by one trained examiner. After the LF and LED assessments, the teeth were histologically evaluated using stereomicroscopy as the gold standard. The sensitivity, specificity, accuracy, and area under the receiver operating characteristics (ROC) curve were calculated according to the appropriate thresholds (T1, sound surface or enamel caries; T2, dentin caries).

RESULTS

For the LFpen device, higher sensitivity and accuracy was found when the adjacent surface was sound at the T1 threshold and no significant differences were found among accuracy at the T2 threshold. For the LED-based device, no significant differences were found among sensitivities at the T1 threshold. At the T2 threshold, specificity was higher when the adjacent tooth had a zirconia restoration.

CONCLUSIONS

It was found that both devices could be used effectively for evaluating approximal surfaces with adjacent restored teeth, regardless of the different kinds of restorative materials.

Er:YAG laser versus scaling and root planing as alternative or adjuvant for chronic periodontitis treatment: a systematic review

AIM

To perform a systematic review to evaluate the erbium-doped: yttrium, aluminium and garnet (Er:YAG) laser versus scaling and root planing (SRP) as alternative or adjuvant for chronic periodontitis treatment.

MATERIAL AND METHODS

We performed a literature search using six electronic databases and completed by manual searches up to July 2013. We conducted a meta-analysis as well as heterogeneity, sensitivity, subgroup and power analyses to clarify and validate the pooled results. The 3-, 6- and 12-month clinical outcomes were evaluated.

RESULTS

Twelve eligible randomized clinical trials were finally included. Our meta-analysis showed that Er:YAG laser resulted in similar clinical improvements as SRP 3 months postoperatively. For subgroups by laser level, quality of trials and fluorescence feedback device, the results remained consistent. The 6- and 12-month observations between Er:YaG laser and SRP demonstrated no difference but inconclusive, due to large heterogeneity. The advantage of Er:YAG laser adjuvant to SRP for periodontitis treatment was not significant.

CONCLUSIONS

This systematic review indicated that the clinical efficacy of Er:YAG laser was similar to SRP 3 months postoperatively. The clinical benefits of Er:YAG laser as adjuvant to SRP was still lacking. Since Er:YAG laser has certain advantages, it could be expected to be a novel short-term alternative choice for chronic periodontitis.

Diagnosis of occlusal caries using laser fluorescence versus conventional methods in permanent posterior teeth: a clinical study

OBJECTIVE

The purpose of this in vivo study was to compare three different caries detection methods [laser fluorescence (LFE), visual examination (VE), and radiological examination (RE)] for the detection of occlusal caries in permanent posterior teeth.

BACKGROUND DATA

Early diagnosis of caries is critical in the management of dental caries.

METHODS

Two examiners assessed the occlusal surfaces of 217 teeth by visual, radiographic, and laser fluorescence (DIAGNOdent Pen) examination methods. After a 1 week interval, randomly selected patients were recalled. Each measurement was repeated by two examiners before the cases were selected for operative intervention to classify lesion depths. Statistical analysis of the data was performed using SPSS and Stata IC. The intra- and inter-examiner reliabilities and reproducibilities of the VE, RE, and LFE were calculated using Cohen's κ statistics. The sensitivities and specificities were plotted in receiver operating characteristic curves. The differences between LFE scores were analyzed using the nonparametric Mann-Whitney U and Wilcoxon tests (α=0.05).

RESULTS

The VE method exhibited the highest sensitivity, accuracy, and κ values among the diagnostic groups in terms of inter-examiner agreement. With regard to the sensitivity, specificity, and likelihood ratios for the two examiners, significant differences were found between sensitivity and specificity for examiner 1, whereas no statistically significant differences were noted between sensitivity and specificity for examiner 2 for the LFE scores.

CONCLUSIONS

The DIAGNOdent pen is useful for the detection of dentinal caries of occlusal surfaces in permanent posterior teeth. Combination with other diagnostic conventional methods may enhance the reliability of this tool.

Anti-infective therapy with an Er:YAG laser: influence on peri-implant healing

In addition to conventional treatment modalities (mechanical and chemical), the use of lasers has been increasingly proposed for the treatment of periodontal and peri-implant infections (i.e., cleaning and detoxification of implant surfaces). Preliminary results from basic studies have pointed to the high potential of the Erbium-doped: Yttrium, Aluminum and Garnet (Er:YAG) laser. Furthermore, preliminary clinical data indicate that treatment with this kind of laser may positively influence peri-implant healing. The aim of this research update is to evaluate, based on the currently available evidence, the use of an Er:YAG laser for the treatment of peri-implant infections and to indicate its potential as a new treatment modality.

Dental optical coherence tomography

This review paper describes the applications of dental optical coherence tomography (OCT) in oral tissue images, caries, periodontal disease and oral cancer. The background of OCT, including basic theory, system setup, light sources, spatial resolution and system limitations, is provided. The comparisons between OCT and other clinical oral diagnostic methods are also discussed.

Characteristics of subgingival calculus detection by multiphoton fluorescence microscopy

Subgingival calculus has been recognized as a major cause of periodontitis, which is one of the main chronic infectious diseases of oral cavities and a principal cause of tooth loss in humans. Bacteria deposited in subgingival calculus or plaque cause gingival inflammation, function deterioration, and then periodontitis. However, subgingival calculus within the periodontal pocket is a complicated and potentially delicate structure to be detected with current dental armamentaria, namely dental x-rays and dental probes. Consequently, complete removal of subgingival calculus remains a challenge to periodontal therapies. In this study, the detection of subgingival calculus employing a multiphoton autofluorescence imaging method was characterized in comparison with a one-photon confocal fluorescence imaging technique. Feasibility of such a system was studied based on fluorescence response of gingiva, healthy teeth, and calculus with and without gingiva covered. The multiphoton fluorescence technology perceived the tissue-covered subgingival calculus that cannot be observed by the one-photon confocal fluorescence method.

Laser-induced fluorescence for subgingival calculus detection: scientific rational and clinical application in periodontology

OBJECTIVE

To review the data available on the laser-induced calculus fluorescence phenomenon and the calculus detection devices as well as to determine the clinical relevance of using commercialized calculus detection devices in periodontal treatment.

METHODS

In vitro or in vivo English publications found on Medline.

RESULTS

In vitro and in vivo studies showed that the devices on the market had a satisfactory detection capacity. Very few studies demonstrated that the erbium:yttrium-aluminium-garnet (Er:YAG) laser debridement, when performed with automatic calculus detection, could lead to improvements at the clinical level, and the outcome was similar to that obtained with conventional treatments.

CONCLUSIONS

Although preliminary data were encouraging, there was a lack of scientific data concerning the calculus detection devices. Therefore, future studies are crucial for determining the clinical relevance of such equipment.

Optical diagnostics in the oral cavity: an overview

As the emphasis shifts from damage mitigation to disease prevention or reversal of early disease in the oral cavity, the need for sensitive and accurate detection and diagnostic tools become more important. Many novel and emergent optical diagnostic modalities for the oral cavity are becoming available to clinicians with a variety of desirable attributes including: (i) non-invasiveness, (ii) absence of ionizing radiation, (iii) patient-friendliness, (iv) real-time information (v) repeatability, and (vi) high-resolution surface and subsurface images. In this article, the principles behind optical diagnostic approaches, their feasibility and applicability for imaging soft and hard tissues, and their potential usefulness as a tool in the diagnosis of oral mucosal lesions, dental pathologies, and other dental applications will be reviewed. The clinical applications of light-based imaging technologies in the oral cavity and of their derivative devices will be discussed to provide the reader with a comprehensive understanding of emergent diagnostic modalities.

Clinical diagnosis of fissure caries with conventional and laser-induced fluorescence techniques

We studied the in vivo validity of dentinal fissure caries diagnosis by visual examination, bitewing radiography, and use of a laser-induced fluorescence device (DIAGNOdent). A total of 144 and second molars with macroscopically intact occlusal surfaces in 41 Chinese young adults were examined visually, by bitewing radiography, and by DIAGNOdent. Visual examination after pit and fissure opening was used as the reference standard. The sensitivity and specificity of detecting caries that had extended into the dentin were, respectively, 0.89 and 0.44 by visual detection of opacity or discoloration after air drying, 0.13 and 1.00 by bitewing radiography to detect radiolucency extending into the dentin, and 0.70 and 0.84 by DIAGNOdent testing with a cut-off score of 40. Caries detection by a combination of visual examination and DIAGNOdent had a sensitivity of 0.67 and specificity of 0.94. Receiver operating characteristic analysis showed that this combined approach was superior to the other methods.

Laser application in non-surgical periodontal therapy: a systematic review

OBJECTIVES

The primary aim was to address the following focused question: What is the clinical effect of laser application compared with mechanical debridement in non-surgical periodontal therapy in patients with chronic periodontitis? A secondary aim was to survey the relevant literature in relation to safety of laser applications.

MATERIAL AND METHODS

Electronic databases of the PubMed and the Cochrane Library were searched and completed by manual searches up to December 2007.

RESULTS

Following screening, 12 publications (11 studies) were eligible for the review. A meta-analysis could not be performed due to the heterogeneity of the studies. The results from a narrative synthesis indicate that Er:YAG laser monotherapy resulted in similar clinical outcomes, both in the short and the long term (up to 24 months), compared with mechanical debridement. There is insufficient evidence to support the clinical application of either CO(2), Nd:YAG, Nd:YAP, or different diode laser wavelengths.

CONCLUSIONS

The Er:YAG laser seems to possess characteristics most suitable for the non-surgical treatment of chronic periodontitis. Research conducted so far has indicated that its safety and effects might be expected to be within the range reported for conventional mechanical debridement. However, the evidence from the evaluated studies is weak.

Immunohistochemical characterization of periodontal wound healing following nonsurgical treatment with fluorescence controlled Er:YAG laser radiation in dogs

BACKGROUND AND OBJECTIVE

The aim of the present study was to immunohistochemically characterize periodontal wound healing following nonsurgical treatment with fluorescence controlled Er:YAG laser radiation in dogs.

STUDY DESIGN/MATERIALS AND METHODS

Five beagle dogs suffering from naturally occurring chronic periodontitis were randomly allocated in a split-mouth design to nonsurgical periodontal treatment using either (a) an Er:YAG laser at 10.2, 12.8, 15.4, 18, and 20.4 J/cm2 (ERL1-5), or (b) an ultrasonic device (VUS) serving as control. The animals were sacrificed after 3 months. Histomorphometrical (e.g. inflammatory cell infiltrate, surface changes, cementum formation), and immunohistochemical parameters (collagen type I, CD68, matrix metalloproteinase (MMP)-8) were assessed.

RESULTS

Inflammatory cell infiltrates of different extent were commonly observed in all treatment groups. However, histomorphometrical analysis revealed new cementum formation with inserting collagen type I fibers along the instrumented root surfaces in most specimens of both ERL (ERL2: 31+/-81 to ERL5: 595+/-575 microm) and VUS (50+/- 215 microm) groups. This was associated with pronounced CD68 and weak MMP-8 antigen reactivity.

CONCLUSION

Within the limits of the present study, it was concluded that both treatment procedures (i) were effective in controlling inflammatory cell infiltrates, and (ii) may support the formation of a new connective tissue attachment.

Real-time detection of dental calculus by blue-LED-induced fluorescence spectroscopy

Successful periodontal therapy requires sensitive techniques to discriminate dental calculus from healthy teeth. The aim of the present study was to develop a fluorescence-based procedure to enable real-time detection and quantification of dental calculus. Thirty human teeth--15 teeth with sub- and supragingival calculus and 15 healthy teeth--covered with a layer of physiological saline solution or blood were illuminated by a focused blue LED light source of 405 nm. Autofluorescence spectra recorded along a randomly selected line stretching over the crown-neck-root area of each tooth were utilized to evaluate a so called calculus parameter R, which was selected to define a relationship between the integrated intensities specific for healthy teeth and for calculus in the 477-497 nm (S(A)) and 628-685 nm (S(B)) wavelength regions, respectively. Statistical analysis was performed and a cut-off threshold of R=0.2 was found to distinguish dental calculus from healthy teeth with 100% sensitivity and specificity under various experimental conditions. The results of the spectral evaluation were confirmed by clinical and histological findings. Automated real-time detection and diagnostics for clinical use were implemented by a corresponding software program written in Visual Basic language. The method enables cost-effective and reliable calculus detection, and can be further developed for imaging applications.

Influence of the condition of the adjacent tooth surface on fluorescence measurements for the detection of approximal caries

The aim of this study was to test whether the status of the adjacent tooth surface has an influence on the signal of a new laser fluorescence (LF) device for the detection of approximal caries. Seventy-eight teeth were selected from a pool of extracted permanent human molars, frozen at -20 degrees C until use. Before being measured the teeth were defrosted, cleaned, and any calculus removed. As a control, a defined approximal surface of each tooth was measured with the LF device holding the tip with the detecting- and the reverse-side on it, but without a neighboring tooth contacting the surface. The proximal site under examination was then placed adjacent to a tooth, which had deep dentinal caries, a composite restoration, a provisional ZnO-Eugenol restoration, or a ceramic restoration. The adjacent tooth with the ZnO-Eugenol restoration, the composite restoration, and the dentinal caries all demonstrated a statistically significant increase of LF readings on sound tooth surfaces. Teeth with enamel or dentinal caries were only slightly (and not statistically significantly) influenced by the different types of neighboring surfaces compared with the control LF readings. It can be concluded that caries detection of approximal tooth surfaces with the new LF system might be influenced by the condition of the adjacent tooth surface.

Evaluation of selective calculus removal by a fluorescence feedback-controlled Er:YAG laser in vitro

OBJECTIVES

To evaluate the removal of subgingival calculus and dental hard tissues depending on the threshold level of a fluorescence feedback-controlled Er:YAG laser.

MATERIAL AND METHODS

Twenty teeth with calculus on the root surface were treated with an Er:YAG laser. Laser settings were 140 mJ and 10 Hz. The initial fluorescence threshold level of 5 [U] was reduced at intervals of 1 [U] for every laser treatment. Areas of residual calculus (RC) were evaluated using a surface analysis software. Loss of dental hard tissues was assessed by histomorphometric analysis of undecalcified ground sections.

RESULTS

Using a threshold value of 5 [U], the median amount of RC was 11% (0-78%). By lowering the threshold levels, the amount of RC decreased [level 1 [U]: 0% (0-26%)]. The laser-treated root surfaces revealed a statistically significant reduction of the cementum thickness [median: 80 microm (0-250)] compared with the non-treated opposite side [median: 90 microm (30-250)] (p<0.05).

CONCLUSION

The amount of RC following laser irradiation depends on the fluorescence threshold level for a feedback-controlled Er:YAG laser. It might be suggested that this laser system may be used with a threshold level even lower than 5 [U] without removing a clinically relevant amount of root cementum.

Application of DIAGNOdent® as a guide for removing carious dentin with Er:YAG laser

OBJECTIVES

The purpose of this study was to investigate the DIAGNOdent values applicable as a guide for removal of outer layer of carious dentin with Er:YAG laser.

METHODS

Carious dentin of human extracted molars was removed by bur with Caries Detector (Group 1: red stained dentin was left, Group 2: light pink stained dentin was left) and by Er:YAG laser with DIAGNOdent value as a guide (30>Group 3>21, 20>Group 4>11, 10>Group 5). The cavity floor dentin after removing carious dentin was examined using microradiograms, EPMA and SEM.

RESULTS

The cavity floor dentin of group 1,3 showed the decreases in the degree of X-ray absorption. In group 2,4 and 5, decrease of Ca, P were not observed. The decrease of Mg was observed on the more superficial part of the cavity floor for group 3 than for group 4.

CONCLUSIONS

When carious dentin was removed using Er:YAG laser, the carious dentin outer layer was ideally removed with DIAGNOdent values: 11-20. DIAGNOdent values: 11-20, could indicate the completion of outer layer removal of carious dentin with Er:YAG laser, but there are some problems that must be addressed before the clinical application.

Influence of fluorescence-controlled Er:YAG laser radiation, the Vectortm system and hand instruments on periodontally diseased root surfaces in vivo

OBJECTIVES

The aim of the present study was to evaluate the effects of fluorescence-controlled Er:YAG laser radiation, an ultrasonic device or hand instruments on periodontally diseased root surfaces in vivo.

MATERIAL AND METHODS

Seventy-two single-rooted teeth (n=12 patients) were randomly treated in vivo by a single course of subgingival instrumentation using (1-3) an Er:YAG laser (ERL1: 100 mJ; ERL2: 120 mJ; ERL3: 140 mJ; 10 Hz), or (4) the Vector ultrasonic system (VUS) or (5) hand instruments (SRP). Untreated teeth served as control (UC). Areas of residual subgingival calculus (RSC) and depth of root surface alterations were assessed histo-/morphometrically.

RESULTS

Highest values of RSC areas (%) were observed in the SRP group (12.5+/-6.9). ERL(1-3) (7.8+/-5.8, 8.6+/-4.5, 6.2+/-3.9, respectively) revealed significantly lower RSC areas than SRP. VUS (2.4+/-1.8) exhibited significantly lower RSC areas than SRP and ERL(1, 2). Specimens treated with SRP revealed conspicuous root surface damage, while specimens treated with ERL(1-3) and VUS exhibited a homogeneous and smooth appearance.

CONCLUSION

Within the limits of the present study, it may be concluded that ERL and VUS enabled (i) a more effective removal of subgingival calculus and (ii) a predictable root surface preservation in comparison with SRP.

Performance of methods of occlusal caries detection in permanent teeth under clinical and laboratory conditions

OBJECTIVES

To compare performance of visual inspection and Laser fluorescence methods to detect occlusal caries lesions under clinical and laboratory conditions in permanent teeth.

METHODS

One hundred and ten sites in 57 third molars scheduled for extraction were examined with visual inspection and laser fluorescence (DIAGNOdent) device by two trained examiners. After the extraction, teeth were re-examined. Then, teeth were sectioned to perform histological validation. Best cut-off points were calculated with ROC analysis, and sensitivity, specificity and accuracy were calculated at D2 and D3 thresholds. Comparisons between the methods and conditions of examination were performed using McNemar test. Inter-examiner agreement in the same conditions and agreement between the methods performed in vivo and in vitro conditions were assessed by Kappa test. Laser fluorescence values obtained in two conditions were compared with Wilcoxon test.

RESULTS

No difference was observed with visual inspection in both conditions. Laser fluorescence performed in vitro presented higher specificity and accuracy at D3 threshold. Visual inspection showed higher reproducibility. After adjustment of cut-off points for laser fluorescence method, there was no difference between the evaluated parameters.

CONCLUSION

Only slightly differences were observed between the examinations performed under clinical and laboratory conditions in the detection of occlusal caries lesions in permanent teeth.

Criteria for a Diagnosis of Caries through the DIAGNOdent

OBJECTIVE

The aim of this study was to investigate the correlation between the demineralization depth measured by dental computed tomography (CT) and the measured value from a non-destructive dental caries diagnosis with a laser.

METHODS

Optimal cut-off points were obtained for enamel and dentin caries, from the measured levels from a dental caries diagnosis with a laser, to investigate the clinical usefulness of a diagnosis using a laser. Using human teeth, the demineralization depth was measured and the caries were diagnosed by a dental caries diagnosis with a laser.

RESULTS

The optimal cut-off point was investigated for accuracy, sensibility, and specificity, which were calculated from the results. These results demonstrated the correlation between the measured values and demineralization depth in both the pit and fissure caries and smooth surface caries. The optimal cut-off points were found to be 16-21 in the fissure caries and 9-11 in the smooth surface caries.

Clinical effectiveness of laser fluorescence, visual inspection and radiography in the detection of occlusal caries

The aim of this in vivo study was to compare a laser fluorescence (LF) device with Ekstrand's visual scoring system and radiographic assessment for detection of occlusal caries. Thirty-eight adults aged 19-35 years participated in the study; a total of 57 third molars with macroscopically intact occlusal surfaces were selected. Two examiners assessed 110 sites by visual inspection (VI), bitewing radiography (BW) and LF. Teeth were then extracted and caries extent assessed by histology. The detection methods were compared by means of sensitivity, specificity, inter-examiner reproducibility (kappa statistics) and area under the ROC curve. VI and LF had similar (p > 0.05) and superior sensitivities than BW (p < 0.05). VI and BW showed similar specificities, which was superior to LF. The inter-examiner reproducibility was good for VI and BW and moderate for LF. The area under ROC curves showed that VI was better than LF. It was concluded that Ekstrand's visual scoring system is the most valid method for caries diagnosis. LF should be considered an adjunct to caries diagnosis.

Detection of Subgingival Calculus With a Novel LED-Based Optical Probe

BACKGROUND

A recently introduced detection device is designed for objective subgingival calculus diagnosis. The aim of the present study was to assess the possibility of detecting subgingival calculus with this novel LED-based optical probe in vitro.

METHODS

Twenty extracted human teeth with calculus on the root surface were fixed on a translation stage. Measurements on the root surface were carried out in increments of 0.25 mm with an angulation of 0 to 10 degrees , 45 degrees , or 90 degrees to the optical fiber. Teeth were covered either with sodium chloride (NaCl) or blood in order to determine the influence of ambient fluids. Successional areas of positive measurements were defined as "length of positive values" (LPV). The results were compared to the clinical and histological findings.

RESULTS

Clinically and histologically apparent calculus on the root surface was accompanied by positive measurement values. A reduction of the angulation between probe and root surface resulted in shorter LPV when measurements were performed in blood (P <0.05) and longer LPV employing NaCl as the ambient fluid (P <0.05). For both blood and NaCl, sensitivity and/or specificity values decreased when using lower angulations.

CONCLUSION

The optical probe offers the possibility of subgingival calculus detection and may, therefore, be suited to determine the endpoint of root surface instrumentation during non-surgical periodontal therapy.