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Laser fluorescence (LF) and differential reflectometry (DR) are two new optical methods which have been used to help diagnose subgingival deposits of dental calculus. This study compared the performance of LF using the KEY3 laser system versus DR using the DetecTar system under controlled laboratory conditions designed to simulate clinical conditions as much as possible. A total of 30 extracted human posterior teeth were set in an anatomical configuration in stone typodonts with impression material replicating the periodontal soft tissues. LF was more accurate than DR (76.2% vs. 68.2%) and gave higher reproducibility (Bangdiwala's B statistic 0.71 vs. 0.54). The better performance of LF makes it the preferred option of the two methods for detection of subgingival dental calculus.

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Deposits of subgingival calculus on the root surfaces of the teeth are difficult to detect with conventional methods such as tactile probing. This study compared the performance of a 655-nm wavelength laser fluorescence (LF) system (DIAGNOdent Classic with a periodontal tip) with conventional periodontal probing under defined conditions in a laboratory simulation, using an experienced examiner. Models with a total of 30 extracted teeth with varying levels of subgingival deposits scattered on their root surfaces were prepared, and silicone impression material applied to replicate periodontal soft tissues. The models were located in a phantom head, and the presence of subgingival calculus recorded at 8 points per tooth (240 sites), then the entire scoring process repeated after 1 and 2 weeks. The optimal LF threshold was determined as a fluorescence score of 7 using Receiver Operating Characteristic curves. When compared the gold standard of direct microscopic examination of roots, LF was more sensitive, specific, and accurate than tactile probing (68.3 vs. 51.7 %; 92.1 vs. 67.8; and 80.2 vs. 59.8 %, respectively), and was also more reproducible (Cohen kappa 0.60 vs. 0.39). These data support the concept of using LF as an adjunct to clinical diagnosis.

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Objective Mineral trioxide aggregate (MTA) cements contain two types of particles, namely Portland cement (PC) (nominally 80% w/w) and bismuth oxide (BO) (20%). This study aims to determine the particle size distribution (PSD) of PC and BO found in MTA. Materials and methods The PSDs of ProRoot MTA (MTA-P) and MTA Angelus (MTA-A) powder were determined using laser diffraction, and compared to samples of PC (at three different particle sizes) and BO. The non-linear least squares method was used to deconvolute the PSDs into the constituents. MTA-P and MTA-A powders were also assessed with scanning electron microscopy. Results BO showed a near Gaussian distribution for particle size, with a mode distribution peak at 10.48 µm. PC samples milled to differing degrees of fineness had mode distribution peaks from 19.31 down to 4.88 µm. MTA-P had a complex PSD composed of both fine and large PC particles, with BO at an intermediate size, whereas MTA-A had only small BO particles and large PC particles. Conclusions The PSD of MTA cement products is bimodal or more complex, which has implications for understanding how particle size influences the overall properties of the material. Smaller particles may be reactive PC or unreactive radiopaque agent. Manufacturers should disclose particle size information for PC and radiopaque agents to prevent simplistic conclusions being drawn from statements of average particle size for MTA materials.

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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.

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This study compared the performance of three laser fluorescence (LF) devices (DIAGNOdent Classic, DIAGNOdent Pen and KEY3 laser) under standardized laboratory conditions for detecting subgingival deposits of calculus on root surfaces of extracted teeth in typodonts. While some studies show the efficacy of LF devices for calculus detection compared with conventional periodontal probes, little is known regarding the differential performance of different LF devices. In this laboratory study, extracted teeth were set in an anatomical configuration in stone typodont models in a phantom head and impression material used to replicate periodontal soft tissues. A total of 240 sites were assessed on three occasions using the three different LF devices and results compared to direct microscopic examination of the roots of the extracted teeth under magnification. The KEY3 showed greater accuracy (86.4 %) than the DIAGNOdent Pen (84 %) and DIAGNOdent Classic (80.2 %). The intra-examiner reproducibility was also higher for the KEY3 (mean Cohen kappa 0.74) than the DIAGNOdent Pen (0.66) and DIAGNOdent Classic (0.6). Of the three LF devices, the KEY3 has greater accuracy and reproducibility.

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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.

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The VistaCam® system (Durr Dental, Bietigheim-Bissingen, Germany) has been suggested as an adjunct to clinical examination for dental caries. This study assessed whether the digital scores obtained for tooth surfaces were affected by the colour of the carious lesions present and by the presence of saliva or blood on the tooth surface. The VistaCam intra-oral ries, or with sound enamel and root surfaces, with or without overlying dental plaque biofilm. Teeth that had undergone root treatment or were stained by tetracycline were also assessed. Readings were taken in the dry state and after application of human stimulated saliva or venous blood onto the surface of the samples. VistaCam fluorescence scores for all samples were similar in the dry state, and when covered with saliva (P > 0.05), however a coating of dilute blood elevated the readings for most samples to a high level (P < 0.01), other than tetracycline stained teeth and dental caries (P > 0.05). Readings for healthy enamel were 0.9-1.1, and these increased up to 2.8 in the presence of blood. VistaCam fluorescence scores are not affected by dryness or moisture from the presence of saliva but increase when traces of blood are present. This problem needs to be taken into account when the device is used clinically, because blood from the gingival crevice is a common contaminant of tooth surfaces when patients have widespread gingival inflammation. There are also issues with elevated scores from background fluorescence from tetracyclines, which need to be considered when the system is in clinical use.

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Visible red (655 nm) laser fluorescence (LF) devices are currently used for identifying deposits of subgingival calculus on the root surfaces of teeth during dental examination and treatment; however, it is not known how the fluorescence readings produced by commercially available LF systems correlate to the nature of the deposits. This laboratory study explored the correlation between LF digital readings and the surface area and volume of subgingival calculus deposits on teeth. A collection of 30 extracted human posterior teeth with various levels of subgingival deposits of calculus across 240 sites were used in a clinical simulation, with silicone impression material used to replicate periodontal soft tissues. The teeth were scored by two examiners by using three commercial LF systems (DIAGNOdent, DIAGNOdent Pen and KEY3). The silicone was removed, and the teeth were removed for photography at × 20 magnification under white or ultraviolet light. The surface area, thickness, and volume were calculated, and both linear least squares regression and nonlinear (Spearman's rank method) correlation coefficients were determined. Visible red LF digital readings showed better correlation to calculus volume than to surface area. Overall, the best performance was found for the KEY3 system (Spearman coefficient 0.59), compared to the Classic DIAGNOdent (0.56) and the DIAGNOdent Pen (0.49). These results indicate that while visible red LF systems vary somewhat in performance, their LF readings provide a useful estimation of the volume of subgingival calculus deposits present on teeth.

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Detecting dental calculus is clinically challenging in dentistry. This study used typodonts with extracted premolar and molar teeth and simulated gingival tissue to compare the performance of differential reflectometry and periodontal probing. A total of 30 extracted teeth were set in an anatomical configuration in stone to create three typodonts. Clear polyvinyl siloxane impression material was placed to replicate the periodontal soft tissues. Pocket depths ranged from 10 to 15 mm. The three models were placed in a phantom head, and an experienced dentist assessed the presence of subgingival calculus first using the DetecTar (differential reflectometry) and then a periodontal probe. Scores from these two different methods were compared to the gold standard (direct examination of the root surface using 20× magnification) to determine the accuracy and reproducibility. Differential reflectometry was more accurate than tactile assessment (79% versus 60%), and its reproducibility was also higher (Cohen kappa 0.54 versus 0.39). Both methods performed better on single rooted premolar teeth than on multirooted teeth. These laboratory results indicate that differential reflectometry allows more accurate and reproducible detection of subgingival calculus than conventional probing, and supports its use for supplementing traditional periodontal examination methods in dental practice.

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