Laser Fluorescence Method Research Articles

Remineralization effect of NaF, NaF with TCP, NaF with CPP-ACP and NaF with CXP varnishes on newly erupted first permanent molars: A randomized controlled trial.

The aim of this study was to evaluate the remineralization effect of NaF, NaF with TCP, NaF with CPP-ACP and NaF with CXP varnishes on newly erupted first permanent molars using laser fluorescence (LF) method. The study was a randomized, double-blind, controlled trial with four parallel groups. The study was carried out in 48 high caries-risk children (DMFS >8), aged 6-7 years with newly erupted permanent first molars (initial lesion with 13 < LF value<30). A total of 140 teeth were divided randomly into four groups (n = 35): G1.Duraphat Varnish containing 5% NaF, G2. Clinpro™ White Varnish containing 5% NaF with TCP, G3.Embrace™ Varnish containing 5% NaF with CXP, G4. MI Varnish containing 5% NaF with CPP-ACP. All dental treatments of the patients were completed before the varnish application. The varnishes were applied to the targeted teeth at baseline, 1 and 3 months. Patients were called for follow-up appointments at 1, 3 and 6 months, and LF scanning was used to monitor mineralization changes. Data were analysed statistically by Wilcoxon signed-rank and Mann-Whitney U-tests. In total, 40 children (122 teeth) completed the trial. At the end of 6 months, the amount of reduction in LF values (indicating remineralization) are as follows: NaF with CXP(6.87 ± 4.32) < NaF with TCP(7.36 ± 7.05) < NaF(7.40 ± 7.03) < NaF with CPP-ACP(8.33 ± 4.90). All of the varnishes resulted in significant decrease in LF measurements and there was no significant difference between control (NaF alone) group and other groups. Only MI varnish had a significantly greater remineralization effect than Embrace™ Varnish (p < 0.05). As a non-invasive approach, CPP-ACP, TCP and CXP containing NaF varnishes have the potential to remineralize initial caries lesions on permanent first molars in high caries-risk children.

OPTIMIZATION OF ONBOARD LASER-FLUORESCENT CONTROL OF ENVIRONMENT POLLUTION BY OIL AND OIL PRODUCTS

The article is devoted to the optimization of sea surface pollution control using the laser-fluorescence method. Two optimization variational problems for remote detection and assessment of sea surface pollution by oil and oil products have been compiled and solved using the fluorescence method. The solution of the first problem on the optimal choice of the wavelength of the emission signal was carried out according to the criterion of achieving maximum information content. The solution of this problem made it possible to determine the wavelength in multipoint laser sounding of sea waters. The solution of the second optimization problem made it possible to determine the optimal form of the dependence of the optical thickness of atmospheric aerosol in the used wavelength range of optical fluorescent emission.

Effect of gas mixture pressure on detection sensitivity of molecular iodine in the atmosphere by laser-fluorescent method using a copper vapor laser (578.2 nm)

The paper reports on the calculation studies of the influence of the pressure of the analyzed gas mixture on the measuring sensitivity of the concentrations of 127I2, 127I129I and 129I2 in atmospheric air by the laser-fluorescence method using a copper vapor laser with a wavelength of 578.2 nm as a fluorescence excitation source. It is shown that for each of these iodine molecules there are pressures at which the highest fluorescence intensity is achieved, which correspond to the best detection sensitivity of the molecules. The results obtained can be used in the development of methods for real-time detection of molecular iodine in the atmosphere.

Clinical Performance of Diagnostic Methods in Third Molar Teeth with Early Occlusal Caries.

The aim of this study was to compare the diagnostic performance of clinical visual examination (ICDAS II), digital periapical radiography (PR), near infrared light transillumination (NIR-LT), and laser fluorescence (LF) to microcomputed tomography (Micro-CT) which is the reference standard for the detection of non-cavitated occlusal enamel and dentin caries in third molar teeth. Potential participants were consecutively recruited. In this prospective study, 101 third molars of 101 patients were examined; the molars had non-cavitated occlusal caries which required extraction. ICDAS II, PR, NIR-LT and LF examinations were carried out by two blinded examiners. Reference standard was determined by micro-CT imaging seven days after extraction. Accuracy rate, sensitivity, specificity, predictive values and areas under receiver operating characteristic (ROC) curves (Az) were statistically analyzed. Nonparametric variables were subjected to the Kruskal-Wallis Test. Significance level was set as p &lt; 0.05. NIR-LT had the highest sensitivity (99.67-99.67%) and accuracy (78.22-77.23%) for the determination of occlusal enamel caries according to examiners 1 and 2, respectively. LF method had the highest sensitivity (70.83-54.17%) and accuracy (66.34-59.41%) for determining occlusal dentin caries according to examiners 1 and 2, respectively. The ROC curve (Az) value ranged between 0.524 and 0.726 for the different methods tested. Most effective methods for the diagnosis of occlusal enamel and dentin caries were determined to be NIR-LT and LF pen methods, respectively. The present prospective clinical study showed that NIR-LT and LF-Pen were a reliable modality for the detection of occlusal enamel and dentin caries without ionizing radiation.

Remote laser fluorescence method for oil leak detection at an excitation wavelength of 266 nm

Subject of study. The possibility of implementing a remote laser fluorescence method to detect oil leaks on the Earth’s surface at a fluorescence excitation wavelength of 266 nm was analyzed and substantiated. Method. Laser-induced fluorescence spectra of clean oil, oil spilled on different types of soil at different time intervals after leakage, and natural and anthropogenic terrain elements were investigated. The experimental setup for remote measurements of laser-induced fluorescence spectra of oil pollution on the Earth’s surface using a laser source with a wavelength of 266 nm, pulse energy of 0.3 mJ, and a single spectral channel of a detector with a central wavelength of 510 nm and a bandwidth of 84 nm is described. The detection possibility of oil pollution against a background of natural vegetation (shrubs and grass) and soil without oil pollution were investigated remotely at a distance of 75 m using emission with a fluorescence excitation wavelength of 266 nm. Main results. Laser-induced fluorescence spectra of commercial oil from the Ryazan oil refinery and oil from Almetyevsk oil field were obtained in addition to the fluorescence spectra of vegetation, soil, and asphalt. Analysis of the data in laser-induced fluorescence spectra indicates that the maximum of the oil spectra is in the range 450–550 nm. Laser-induced fluorescence from vegetation is the largest interference signal in the detection of oil leaks on the Earth’s surface. Remote detection of oil pollution against the background of vegetation and other landscape elements was experimentally demonstrated both immediately after pollution and two days later. Practical significance. The possibility of remote monitoring of oil pollution on the Earth’s surface was experimentally demonstrated at a fluorescence excitation wavelength of 266 nm at distances close to safe aircraft flying altitudes.

Effects of different remineralization agents on MIH defects: a randomized clinical study.

The aim of this study was to present a comparative evaluation of the long-term efficacy of fluoride varnish and pastes containing CPP-ACP and CPP-ACP with fluoride (CPP-ACFP) in the remineralization of creamy-white and yellow-brown defects in permanent first molars with MIH. The study included 120 teeth with yellow-brown or creamy-white defects in 67 children (37 girls, 30 boys) aged 6-9 years (mean, 7.2) who were newly diagnosed with MIH with no substance loss or caries or prior restorative treatment. The patients were randomly divided into the experiment groups; control (oral hygiene motivation only), fluoride varnish, and pastes containing CPP-ACP and CPP-ACPF, and followed up for 24 months. The evaluations were made based on the ICDAS criteria and the measurements which were performed using the laser fluorescence method (DIAGNOdent, KaVo, Biberach, Germany) in the follow-ups. The research was completed with 49 patients (23 females, 26 males; mean age, 7.7) and 90 teeth. All remineralization agents increased remineralization rates in both creamy-white and yellow-brown colored defects without presenting any statistically significant difference at the end of the follow-up period (p > 0.05). However, the effects of fluoride varnishes were late to observe when compared to pastes containing CPP-ACP and CPP-ACPF. Pastes containing calcium and phosphate may be recommended for the longer-term preservation of teeth with yellow-brown defects which showed a post-eruptive breakdown in a shorter time. There is a lack of studies investigating MIH treatments in which lesion appearance was recorded. This study evaluated creamy-white and yellow-brown MIH defects separately and reported long-term results of different remineralization agents.

Laser Fluorescence and Extinction Methods for Measuring the Flow and Composition of Milk in a Milking Machine

Automation of milking systems is linked to accurate measurement of fluctuations in milk flow during milking. To assess the fluctuations of the milk flow, the formation and movement of milk portions in the milking machine-milk pipeline system was studied. By considering the movement of a milk plug along the milk pipeline, a hydraulic model of the formation of a critical volume of milk in the milking machine manifold was compiled. In practice, the most expedient way of determining milk flow parameters may be to measure the laser fluorescent and extinction responses of moving air-milk mixture. We have implemented a new laser sensing method for measuring the flow rate and composition of milk on the basis of counting the optical response pulses received from moving dispersed components by a CCD array or a randomized fiber optic bundle. Using the developed laser sensors, the theoretical model of milk flow was tested.

Prospects for multimodal visualisation of biological tissues using fluorescence imaging

We investigate skin optical clearing in laboratory animals ex vivo and in vivo by means of low-molecular-weight paramagnetic contrast agents used in magnetic resonance imaging (MRI) and a radiopaque agent used in computed tomography (CT) to increase the sounding depth and image contrast in the methods of fluorescence laser imaging and optical coherence tomography (OCT). The diffusion coefficients of the MRI agents Gadovist®, Magnevist®, and Dotarem®, which are widely used in medicine, and the Visipaque® CT agent in ex vivo mouse skin, are determined from the collimated transmission spectra. MRI agents Gadovist® and Magnevist® provide the greatest optical clearing (optical transmission) of the skin, which allowed: 1) an almost 19-fold increase in transmission at 540 nm and a 7 – 8-fold increase in transmission in the NIR region from 750 to 900 nm; 2) a noticeable improvement in OCT images of skin architecture; and 3) a 5-fold increase in the ratio of fluorescence intensity to background using TagRFP-red fluorescent marker protein expressed in a tumour, after application to the skin of animals in vivo for 15 min. The obtained results are important for multimodal imaging of tumours, namely, when combining laser fluorescence and OCT methods with MRI and CT, since the contrast agents under study can simultaneously enhance the contrast of several imaging methods.

What diagnostic strategy performs better for caries lesion detection on proximal surfaces of adolescents?

To evaluate the performance of visual inspection alone and associated to radiographic and laser fluorescence (LF) methods in detecting non-evident caries lesions at adolescents' proximal surfaces. Adolescents (12 to 17years old) were assessed for the presence of caries lesions through visual inspection, radiographic examination, and LF method (DIAGNOdent pen), at non-cavitated (NC) and cavitated lesion (CAV) thresholds. Temporary separation with orthodontic rubbers followed by direct visual inspection was the reference standard method. Two examiners conducted the examinations, and the first examiner reassessed around 20% of the sample, to evaluate inter- and intra-examiner reproducibility, respectively. Sensitivity, specificity, accuracy, and utility values were calculated for the methods alone and combined with visual inspection using two different strategies: simultaneous and sequential combination. A total of 834 proximal surfaces (51 adolescents) were included. Visual inspection presented higher reproducibility values (higher than 0.98). Moreover, visual inspection presented higher sensitivity (around 0.51) than those obtained with other diagnostic strategies (varying from 0.09 to 0.20) at the NC threshold. For CAV, visual inspection presented higher specificity (0.996) than the sequential association with adjunct methods (around 0.97), but with lower sensitivity. Accuracy and utility values for combined strategies were similar or lower than those achieved with the visual inspection performed alone. Visual inspection alone performs better for detecting caries lesions in premolars and molars of adolescents than other diagnostic strategies. The best diagnostic strategy for caries detection of proximal caries lesions in adolescents is the visual inspection alone.

Caries Inhibition of Pit and Fissure Non Cavitated Lesions in Children by Low Level Lasers – A Clinical Study

Background: The incipient non-cavitated carious lesion are characterized by subsurface dissolution which have potential to remineralize. Traditional remineralization protocols have varying results. An effective remineralizing protocol thus would be one which brings about a change in enamel crystal and makes it more resistant to acidic challenges of oral cavity. Material &amp; Methods: 102 patients of either sex, between age of 6 - 18 years having incipient pit and fissure caries on first or second mandibular molar were selected and its respective contralateral tooth type served as control. Occlusal scanning for both groups was done by LASER fluorescence method (DIAGNOdent) and this was baseline value. Group B (Test) was irradiated with 810 nm AlGaAs low level LASER for 30 seconds followed by application of CPP-ACP F remineralizing paste. In Group a (Control) only remineralization paste was applied. The LASER fluorescence values were recorded after 7 days and the treatment protocol repeated. 18 months follow up at 6 monthly intervals included LASER fluorescence serial scanning. Fall in values from baseline indicates remineralization. Statistical analysis was done.

Monitoring the results of enamel demineralization treatment with the caries infiltration method (according to laser fluorescence value)

Relevance. In the actual dentistry a special place takes opportune diagnosis of early stages of dental caries and effective non-surgical treatment. In the recent times new approaches, technologies and methods for diagnosing focal demineralization of tooth enamel have been developed, among which the laser fluorescence method is widely used. Purpose. To study the results of local enamel demineralization treatment with the caries infiltration method according to laser fluorescence value. Materials and methods. The method of caries infiltration was applied in 99 permanent teeth with local enamel demineralization in 15 children aged 10-16 years. Laser fluorescence method was used for enamel demineralization assessment before and immediately after the treatment, after 6, 12 and 18 months. Three study groups were formed according to laser fluorescence value before the treatment: the first one – values 14-20 (initial enamel demineralization), the second one – values 21-29 (deep enamel demineralization), the third one – values ≥ 30 (enamel and dentine demineralization). Proportions (%), mean-values and standard errors (M±m) were calculated, significance (p) of differences was assessed according to Students’ criteria (t) at p &lt; 0.05. Results. During 18 months after caries infiltration caries cavities forming were not revealed. The mean-values of laser fluorescence were in the first group before the treatment 17.38 ± 0.27, after the treatment 5.00±0.82, after 18 months – 4.82 ± 0.79; in the second group 25.42 ± 0.38, 15.25 ± 0.78 and 13.96 ± 0.75, in the third group 33.08 ± 0.69, 22.54 ± 1.39 and 20.77 ± 1.44 respectively. The differences between the values before and after the treatment were significant statistically (p &lt; 0,001) in all groups. After 18 months the laser fluorescence values corresponding to healthy enamel were revealed in 94.1% cases in the first group, in 50.0% cases in the second group, and in 7.7% cases in the third group.Conclusions. Local enamel demineralization treatment of permanent teeth in children with the caries infiltration method prevented caries cavity forming. Monitoring laser fluorescence values revealed that the results of the treatment with the caries infiltration method depended on the depth of dental hard tissue demineralization.

Use of alaser fluorescence device for the in vitro activity assessment of incipient caries lesions.

To evaluate the progression of demineralization during orthodontic treatment, the assessment of lesion activity is important in addition to the detection of lesion extent. This study aimed to evaluate the ability of laser fluorescence measurements to differentiate between active and inactive initial lesions in vitro. In all, 63extracted, permanent human teeth were available for the study. On each occlusal investigation site, surface extent and activity of caries lesions were classified visually using ICDAS/ICCMS (International Caries Detection and Assessment System/International Caries Classification and Management System) criteria, following laser fluorescence measurements. Teeth were hemisected and assessed for lesion depth. Methyl red dye was applied to validate lesion activity on the sections. AMann-WhitneyU-test was performed to evaluate differences between laser fluorescence measurements for active and inactive lesions. For visual and laser fluorescence findings, diagnostic accuracy (Az, sensitivity and specificity) were calculated. A total of 19sound surfaces and 44surfaces with ICDAS codes 1/2 were classified visually. The differences in laser fluorescence measurements between active and inactive lesions were not significant for the initial lesions (p > 0.05). Sensitivity/specificity for lesion depth was 90.5/92.3% (Az = 0.894), respectively, for visual assessment and 69.1/76.9% (Az = 0.745), respectively, for laser fluorescence. Sensitivity/specificity for activity assessment was 68.6/85.0% (Az = 0.768) for the visual method. For laser fluorescence measurements, no diagnostic accuracy values could be calculated for caries activity assessment. The visual detection and activity assessment of initial lesions was more suitable than the laser fluorescence method. Based on the results of this in vitro study, use of laser fluorescence cannot be recommended for distinguishing between active and inactive initial caries lesions on occlusal surfaces.

Determination of the Sequence of Intersecting Lines Between Toners and Seals by Laser Fluorescence Microscope.

Fluorescence microscope is considered to be one of the most effective ways to examine the sequence of intersecting seal and toner lines of questioned documents. In reality, however, the toner (mainly divided into compact and noncompact toners) and seal of a questioned document have such a complex morphology and sequence of crossing lines that current methods cannot meet the requirement of practical document identification. In view of the challenges of document examination, a laser fluorescence microscope and method are developed in this study. The developed microscope provides additional functionality to traditional fluorescence microscopes of transmitted light modality, laser excitation, selectable excitation wavelength, and selectable fluorescence filters. The results obtained from the method of comparisons between transmitted light and fluorescence modalities were positive under most conditions, particularly for noncompact toner examination for which a 100% accuracy rate and 90% detection rate were achieved in blind testing.

Laser fluorescence method for detecting oil pipeline leaks at a wavelength of 355 nm

The possibility of using the laser fluorescence method for detecting leakage of oil pipelines at a fluorescence excitation wavelength of 355 nm was analyzed. The results of experimental studies of the spectra of laser-induced fluorescence of clean crude oils and crude oils spilled on the soil as well as natural and anthropogenic elements of the site naturally located on the land are presented. It is shown that the fluorescent signal from oil spills on the Earth’s surface can be compared with that from vegetation and water bodies. However, the fluorescent signal from oil spills can be distinguished from that from vegetation and water bodies by analyzing the shape of the fluorescence spectra.

In-Vitro Comparison of The Validity and Reproducibility of Laser Fluorescence and Electrical Method in the Diagnosis of Initial Occlusal Caries

In-Vitro Comparison of The Validity and Reproducibility of Laser Fluorescence and Electrical Method in the Diagnosis of Initial Occlusal Caries

Laser fluorescence method for detecting oil pipeline leaks at a radiation wavelength of 355 nm

Laser fluorescence method for detecting oil pipeline leaks at a radiation wavelength of 355 nm

Selection of emission detection ranges for the laser method of plant stress revealing at a fluorescence excitation wavelength of 355 nm

The paper considers the development of a laser fluorescent method for the detection of plant stress conditions. The results of experimental studies of laser-induced fluorescence spectra of plants in normal and various stress conditions caused by various pollutants in the soil are presented for the laser wavelength of fluorescence excitation of 355 nm. A comparative analysis of various options has been carried out for choosing the spectral ranges of laser-induced fluorescent radiation plant registration. It is shown that for the task of monitoring the state of plants, the most effective (from the point of view of reliability of correct detection of stress conditions) ranges of fluorescent radiation registration are spectral ranges with central wavelengths of 685 and 740 nm.

In vivo assessment of clinical, radiographic and laser fluorescence examinations for the detection of secondary caries in Class I restorations

ABSTRAKTWstęp: Współczesna stomatologia zachowawcza oparta jest głównie na pracy z materiałami kompozytowymi. Jest to związane nie tylko z możliwością ich kompleksowego zastosowania, ale także z estetycznymi względami, które można osiągnąć dzięki szerokiej gamie tych materiałów. W przypadkach, w których nie jest możliwe prawidłowe wykonanie uzupełnień kompozytowych, należy rozważyć zastąpienie go alternatywnym materiałem, który zapewni bardziej stabilną rekonstrukcję tkanek zęba. Nieprawidłowo wykonane odbudowy kompozytowe w stosunkowo krótkim czasie mogą prowadzić do powstania nieszczelności brzeżnej, co przyczynia się do akumulacji płytki nazębnej i rozwoju próchnicy wtórnej.Celem pracy było dokonanie in vivo oceny przydatności trzech różnych metod diagnostycznych (badania klinicznego, fluorescencji laserowej oraz radiografii) w wykrywaniu próchnicy wtórnej w zębach posiadających wypełnienia amalgamatowe lub kompozytowe w klasie I wg Blacka.Materiały i metody: Badaniem objęto grupę 94 pacjentów w wieku 17–67 lat. Oceniono łącznie 200 wypełnień z materiałów złożonych i amalgamatu, w których stwierdzono obecność nieszczelności brzeżnej, przebarwienie brzegów wypełnienia lub przylegających tkanek zęba. Nie uwzględniano zębów z widocznymi ogniskami próchnicy wtórnej. Przeprowadzono badanie kliniczne, ocenę fluorescencji laserowej oraz badanie radiologiczne zębów zakwalifikowanych do oceny. Wyniki: Obecność próchnicy wtórnej stwierdzono w przypadku 137 spośród 200 badanych zębów. Metoda fluorescencji laserowej i badanie radiologiczne wykazały niską czułość wykrywania próchnicy wtórnej (odpowiednio 0,31 i 0,39). Obydwie metody wykazywały natomiast wyższą swoistość (odpowiednio 0,86 i 0,98) oraz dokładność (odpowiednio 0,49 i 0,58). Wnioski: Badanie kliniczne jest najskuteczniejszą metodą diagnozowania wtórnych ognisk próchnicy w uzupełnieniach klasy I wg Blacka. Fluorescencja laserowa oraz badania radiologiczne powinny być przeprowadzane wyłącznie w ramach uzupełnienia badania klinicznego.

ПРОГНОЗИРОВАНИЕ И ДИАГНОСТИКА РЕПРОДУКТИВНЫХ НАРУШЕНИЙ, АССОЦИИРОВАННЫХ С ГЕНИТАЛЬНЫМ ТУБЕРКУЛЁЗОМ, У ЖЕНЩИН

Diagnosis of tuberculosis of female genitalia is based on a complex of traditional and new diagnostic methods used in a certain sequence in outpatient and/or inpatient settings. Because of insufficiently effective diagnostic tests, genital tuberculosis is often detected in irreversible anatomical changes, when the prospects for restoring the reproductive function are unsatisfactory. The aim of the work was to identify socio-economic and biomedical risk factors for reproductive disorders associated with genital tuberculosis in order to create statistical models for the prediction and diagnosis of these disorders. To study the connection between the presence of genital tuberculosis and a number of prognostic and diagnostic features, the method of nonlinear regression analysis (logistic regression) was used. Statistical models of prognosis and diagnosis of reproductive disorders associated with genital tuberculosis (HT) in women at the outpatient stage are proposed. The forecast model included clinical and anamnestic predictors: prolonged subfebrile condition, weight loss, increase in inguinal lymph nodes, membership in the social group «female students», contact with tuberculosis patients, tuberculin specimen turnover, presence of pulmonary tuberculosis in the anamnesis. The statistical diagnostic model included the following important methods: enzyme immunoassay, laser fluorescence method, Diaskin-test, hysterosalpingography (segmented fallopian tubes), determination of progesterone, estradiol and testosterone levels in the blood serum (decrease of these hormones).

An Assessment of the Impact of Zidovudine on Rat Teeth Ontogenesis with Quantitative Laser Induced Fluorescence and an Histomorphological Analysis

Objectives: It is known that many conditions may impact on dental organ development at foetus or new-born stages. The most important influence in this case is caused by genetic predispositions but also by drugs delivered prenatally and postnatally to the organism. The goal of this research was to find if the applications of Zidovudine to mothers’ organisms of rats can caused some abnormalities in dental organs of new-borns. Methods: The study was performed on 20 Wistar female rats and their 36 new-borns bred. The group of adult pregnant rats was divided on two sub-groups: with and without Zidovudine receiving. The influence of Zidovudine administered was assessed by using the quantitative laser-induced fluorescence and compared with the group without Zidovudine receiving as a reference subjects. Results: In result the dependences in Zidovudine receiving were obtained and the changes in tissues were detected by use the laser fluorescence method. Moreover the differences between groups with and without Zidovudine are obtained in morphological results. The stronger impact of drug was obtained for mothers rats than new-borns. Conclusions: All obtained results show usefulness laser fluorescence in dental organ assessment.