Dental Curing Light Research Articles

Effect of Curing Light with Different Intensities on the Penetration of Silver and Fluoride Ions and Dentin Hardness in Primary Carious Molars Following Silver Diamine Fluoride Application: A Comparative Microscopic Ex Vivo Study.

A paradigm shift from surgical to medical approach for caries management has popularized silver diamine fluoride (SDF) as a preventive and interim caries arrest medicament. Few studies conducted have explored the effect of curing light on SDF's microbial property, its penetration, and effect on dentin. However, there is a research gap regarding the effect of different intensities of curing light on SDF performance. To determine the effect of different curing light intensities on SDF penetration depth and dentin hardness in carious lesions of primary molars. Silver diamine fluoride was applied on 30 extracted carious primary molars. Teeth were randomly allocated into three groups-(1) control group, no light curing after application of SDF; (2) light curing of SDF with low intensity (1000 mW/cm2); and (3) light curing of SDF with high intensity (2500 mW/cm2). A scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis was performed to check ion penetration after 1 week, and a Vickers hardness test was used to assess dentin hardness of both infected and affected dentin layers at 1-week and 1-month intervals. Based on the distribution of data, parametric and nonparametric tests were applied. Statistical Package for the Social Sciences (SPSS) version 26 was used for statistical analysis. The level of significance was set at 5%. Silver diamine fluoride penetrated beyond the carious lesion in all three groups. The mean silver ion precipitation in infected dentin in group III (16.90 ± 0.68) was maximum, whereas it was found to be minimum in group II (7.31 ± 0.63). The mean fluoride ion precipitation in affected dentin in group III (4.06 ± 0.41) was highest and least in group II (3.09 ± 0.58). A considerable increase in mean dentin hardness of infected dentin was observed in all three groups (214.00 ± 89.06, 218.00 ± 75.17, 231.00 ± 98.86, respectively; p < 0.001) after 1 month. Applying SDF to carious lesions using a high-intensity dental curing light induced more silver ion precipitation in infected dentin and increased its hardness. Bhatt R, Patel M, Thakkar A, et al. Effect of Curing Light with Different Intensities on the Penetration of Silver and Fluoride Ions and Dentin Hardness in Primary Carious Molars Following Silver Diamine Fluoride Application: A Comparative Microscopic Ex Vivo Study. Int J Clin Pediatr Dent 2024;17(7):766-772.

Dental Curing Light : Sustainability, Environmental and Cancer Responsibility

Dental Curing Light : Sustainability, Environmental and Cancer Responsibility

Morphological changes and viability of Streptococcus mutans biofilm treated with erythrosine: A confocal laser scanning microscopy analysis.

Antimicrobial photodynamic therapy (a-PDT) is a modality that aims to induce microorganisms through visible light, a photosensitizer, and molecular oxygen. This therapy has shown promising results in controlling cariogenic biofilm in vitro and in vivo counterparts. This study investigated bacterial viability and morphological characterization of Streptococcus mutans mature biofilms after combination of erythrosine and a high potency dental curing light. Biofilms were formed on saliva-coated hydroxyapatite disks in batch culture. The samples were performed in triplicates. Fresh medium was replaced daily for five days and treated using 40 μM of E activated by HL 288 J/cm2 and total dose of 226 J at 1200 mW/cm2. Phosphate buffer saline and 0.12% of chlorhexidine were used as negative and positive control, respectively. After treatment, biofilms were assessed for microbial viability and morphological characterization by means of bio-volume and thickness. COMSTAT software was used for image analysis. Data were analyzed using two-way ANOVA followed by Tukey test with significance level 5%. The application of a-PDT and CHX treatments decreased S. mutans bacterial viability. The image analysis showed more red cells on biofilms when compared to other groups, demonstrating photobacterial killing. Erythrosine irradiated with a high potency curing light can potentially act as an antimicrobial tool in the treatment of cariogenic biofilms. The morphology and viability of microorganisms were impacted after treatment. Treatment with photodynamic therapy may be able to reduce the bio-volume and viability of bacteria present in biofilms. CLINICAL RELEVANCE AND RESEARCH HIGHLIGHTS: The use of the a-PDT technique has been applied in dentistry with satisfactory results. Some applications of this technique are in stomatology and endodontics. In the present study, we sought to understand the use of photodynamic therapy in the control of biofilm and the results found are compatible with the objective of microbiological control proposed by this technique, thus raising the alert for future studies in vivo using the combination of a-PDT with erythrosine, since they are easily accessible materials for the dental surgeon and can be applied in clinical practice.

Efficient Photopolymerization of Dental Resin Composites Using the Photoluminescent Long Afterglow of Sr2MgSi2O7:Eu2+,Dy3.

Dental curing light with blue emission acts as the excitation source for the photopolymerization of the dental composite resin to achieve dental repairing. However, the current repair methods still suffer from a low monomer conversion degree and incomplete resin curing. In this study, novel dental resin composites (DRCs) were prepared by combining Sr2MgSi2O7:Eu2+,Dy3+ (SMSED), a photoluminescent material with a blue long afterglow, and dental resin composites. The curing depth, double bond conversion, elastic modulus, compressive strength, water absorption and solubility, and cytotoxicity were investigated systematically. The results suggest that adding 1 wt % SMSED to dental resin composites can maximize the curing depth and double bond conversion rate of DRCs and reduce its water absorption capacity without affecting the mechanical properties and biological toxicity. This work explores the practical applications of SMSED in dental resin composites, which provides an important reference for further improving the effect of dental caries repair.

Evaluation of a novel caries detecting oral rinse

AimLumiCare™ Caries Detection Rinse (LC Rinse), a starch-based rinse, illuminates active initial caries (positive response) using dental curing light, thus augmenting the dentist’s visual examination. This clinical study investigated if active caries as assessed by the International Caries Detection and Assessment System (ICDAS) were more likely to have positive LC Rinse response than sound surfaces and inactive caries.Methods25 subjects participated in the study. Caries was assessed on selected teeth and the entire dentition, firstly using ICDAS and then by fluorescence evaluation after LC Rinse application. Data were statistically analyzed using Diagnostic Odds Ratio (OR) and Chi-square test X2 (α = 0.05). Sensitivity (Se), specificity (Sp), and Diagnostic accuracy (DA) were calculated.ResultsWith selected teeth, active caries were 638.6 times (60.05 with full dentition) more likely to have positive LC Rinse response than sound surfaces and inactive caries combined (X2, p < 0.01) and 191.67 times (18.35 with full dentition) than inactive lesions only (X2, p < 0.01). With combined sound surfaces and inactive caries, Se, Sp, and DA of LC Rinse assessment were 0.94, 0.98, and 0.96 respectively.ConclusionsLC Rinse can distinguish between active caries, inactive caries and hypomineralization, and can augment caries detection with high sensitivity, specificity, and diagnostic accuracy.

Can We Use Our Dental Curing Lights to Polymerize Objects Produced with 3D Resin Printer?

BACKGROUND&#x0D; Dental treatment objects produced with 3D resin printers barely polymerize after fabrication. They need post-curing and an extra polymerization oven is required. Present study is aimed to determine the effectiveness of dental curing lights for post-curing of objects produced with a 3D resin printer.&#x0D; METHODS&#x0D; Samples were produced with Alias ​​Sharp &amp; Rigid Model 3D Printing Resin in Photon Mono X 3D resin printer. The control set samples were cured with UV light for 2 min in Wash &amp; Cure Plus device. T-20, T-40 and T-60 set samples were exposed to VALO Cordless curing light for 20, 40 and 60 seconds respectively. The hardness was measured with the Shore D Durometer. Then, the samples were subjected to compression. For statistical analysis, one way analysis of variance (ANOVA) and Tukey test was used.&#x0D; RESULTS&#x0D; The set cured with VALO Cordless for 20 seconds showed the highest strength. Compressive strength decreased with prolongation of the curing time. All experimental sets showed significantly higher hardness than the control set. Hardness increased gradually in the 20 and 40 second sets, but the difference between the 40 and 60 second sets was not significant. Also, color change was observed in the experimental sets samples.&#x0D; CONCLUSIONS&#x0D; Dental curing lights are effective in post-curing 3D printer resins.

Application of Er,Cr:YSGG laser versus photopolymerization after silver diamine fluoride in primary teeth

Examine the effect of dental curing light and laser treatments applied after Silver Diamine Fluoride (SDF) on dentin hardness in carious primary molars. This in-vitro study consisted of 30 extracted primary molars with caries extending into dentin without pulpal involvement. The collected teeth were randomly divided into three groups: group 1: received SDF then Sub-ablative low-energy of Er,Cr:YSGG laser, group 2: received SDF followed by application of curing light for 40 s, group 3: had SDF treatment only. In all groups, 38% Ag (NH3)2F SDF was used. Vickers hardness test was performed on sound dentin below carious lesion. Kruskal–Wallis Test was used to determine the mean difference in dentin hardness of the groups at 5% Significance level using SPSS software. Surface hardness of sound dentin below the carious lesion was statistically significantly higher in the laser + SDF group (891.24 ± 37.33 kgf/mm2) versus the two other groups (Light cure + SDF = 266.65 ± 90.81 kgf/mm2 and SDF only = 117.91 ± 19.19 kgf/mm2) with p-value ≤ 0.001. Although Photopolymerization of SDF increases the surface hardness of sound dentin below the carious lesion, applying laser after SDF has the highest surface hardness due to the laser’s sub-ablation of dentin.

No-primer adhesive vs. self-adhesive resin: bonding strength following LED curing.

The goal of this study was to compare the shear bond strength (SBS) and failure modes of three different adhesive resins following the use of two different dental curing light units. A total of 160 human premolars were randomly divided into four groups (N = 40 for each): group1, Transbond™ XT (3M Unitek, Monrovia, CA, USA) adhesive paste; group2, Heliosit Orthodontic paste with no primer; group3, Maxcem Elite (Kerr, Orange, CA, USA) self-adhesive resin with prior etching; group4, Maxcem Elite self-adhesive resin with no etching. Each group was further divided into 2subgroups: half (named "a") were cured with VALO LED (Ultradent Products, South Jordan, UT, USA), and the other half (named "b") with the Elipar LED unit (3M Unitek LED, Monrovia, CA, USA). The brackets were submitted to SBS testing 24 h after bonding. Adhesive Remnant Index (ARI) scores and bonding time were also measured. Two-way analysis of variance (ANOVA) and Kruskal-Wallis tests were used for statistical analysis. No significant differences in SBS were observed when comparing the two different LED devices within the same bonding material. The mean SBS of group1 was significantly higher compared to groups2, 3, and 4 (p < 0.001). Mean SBS values of groups2 and 3 were significantly higher than that of group4 (p < 0.001). ARI scores were significantly different in groups4a and 4b compared to the other groups (p < 0.05). Group4a showed significantly lower bonding time/tooth compared to the other groups except to groups3a and 4b (p < 0.001). Decreasing curing time using high-power LED device did not significantly affect SBS. However, the composite type did affect SBS.

Degree of conversion and microhardness of resin cements photoactivated through glass ceramic.

BackgroundTo assess whether glass-ceramic shade, thickness and translucency affect degree of conversion (DC) and Knoop microhardness (KHN) of resin cements photoactivated using light-emitting diode (LED) or quartz-tungsten-halogen (QTH) units. Material and MethodsGlass-ceramic blocks were cut (2, 3 and 4mm) and sintered. For DC FT Raman spectroscopy (n=3), film specimens of cements (RelyX ARC, U200, Veneer, C&B) were obtained. For KHN test (n=3), cements were inserted in cylindrical matrix and covered by polyester strip. Specimens were photoactivated (30s) using LED or QTH according to each group: direct photoactivation (DP), interposing ceramic specimens or no photoactivation (NP). Data were analysed by ANOVA and Tukey’s test, Kruskal-Wallis and Dunn’s tests (p<0.05). ResultsCeramic features had significant effect on DC of RelyX ARC, U200 and Veneer (p<0.0017). Light source had no effect (p=0.9512). C&B and Veneer had higher DC, followed by dual cements. NP dual cements showed the lowest DC. For KHN, ceramic shade (p=0.1717) and light source (p=0.1421) were not significant, but ceramic translucency, thickness and resin cement were significant (p=0.0001). KHN was higher for U200 followed by ARC, and lowest for Veneer. ConclusionsDC was affected by ceramic shade, translucency and thickness. KHN was dependent on ceramic translucency and thickness. Higher DC and KHN were achieved for dual-cured cements photoactivated through 2mm-thick low translucent or 3mm-thick high translucent glass-ceramic. Key words:Cementation, composite resin cements, dental curing lights, glass ceramics.

In vitro antimicrobial effect of curcumin-based photodynamic therapy on Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans

Photodynamic therapy (PDT) is a bactericidal method, which has recently been introduced in the field of dental medicine and therapy. Curcumin, a compound isolated from Curcuma longa L., exerts potent phototoxic effects at micromolar concentrations. The aim of our study was to explore the in vitro antimicrobial effect of curcumin-based PDT on two major etiological agents of periodontitis, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. P. gingivalis ATCC33277 and A. actinomycetemcomitans ATCC24523 suspension was irradiated with blue LED (BL) (450-470 nm, output power density 1.2 W/cm2) for 20-60 s (6-18 J/cm2), treated with curcumin (2 min), or subjected to a combination of curcumin treatment and BL irradiation (60 s, 18 J/cm2). A suspension of chlorhexidine gluconate (CHG) was used as the positive control. All bacterial suspensions used were serially diluted, plated, and incubated anaerobically or microaerobically. The numbers of colony-forming units (CFUs) were counted on day 7. One-way analysis of variance (ANOVA) and Tukey's HSD tests were used for statistical analysis. BL irradiation at 6, 12, and 18 J/cm2 alone reduced the number of CFUs of both P. gingivalis and A. actinomycetemcomitans, but the reduction was not statistically significant. Compared with BL irradiation alone, curcumin solution at 20 μmol/L used alone achieved a lower reduction in the number of CFUs. Combined use of BL at 18 J/cm2 20 μmol/L curcumin treatment yielded a log reduction of 0.43 and 1.51 for P. gingivalis and A. actinomycetemcomitans CFUs, respectively. Suspensions treated with 0.12 % CHG showed a log reduction of 0.29 and 0.28 for P. gingivalis and A. actinomycetemcomitans CFUs, respectively. Although the bactericidal and growth-inhibitory effects of BL alone on P. gingivalis and A. actinomycetemcomitans were not significant, A. actinomycetemcomitans was susceptible to photodynamic inactivation by the combination of BL and curcumin.

Shedding light on a potential hazard: Dental light-curing units

BackgroundDental light-curing units (LCUs) are powerful sources of blue light that can cause soft-tissue burns and ocular damage. Although most ophthalmic research on the hazards of blue light pertains to low levels from personal electronic devices, computer monitors, and light-emitting diode light sources, the amount of blue light emitted from dental LCUs is much greater and may pose a “blue light hazard.” MethodsThe authors explain the potential risks of using dental LCUs, identify the agencies that provide guidelines designed to protect all workers from excessive exposure to blue light, discuss the selection of appropriate eye protection, and provide clinical tips to ensure eye safety when using LCUs. ResultsWhile current literature and regulatory standards regarding the safety of blue light is primarily based on animal studies, sufficient evidence exists to suggest that appropriate precautions should be taken when using dental curing lights. The authors found it difficult to find on the U.S. Food and Drug Administration database which curing lights had been cleared for use in the United States or Europe and could find no database that listed which brands of eyewear designed to protect against the blue light has been cleared for use. The authors conclude that more research is needed on the cumulative exposure to blue light in humans. Manufacturers of curing lights, government and regulatory agencies, employers, and dental personnel should collaborate to determine ocular risks from blue light exist in the dental setting, and recommend appropriate eye protection. Guidance on selection and proper use of eye protection should be readily accessible. Conclusions and Practical ImplicationsThe Centers for Disease Control and Prevention Guidelines for Infection Control in the Dental Health-Care Setting–2003 and the Occupational Safety and Health Administration Bloodborne Pathogen Standard do not include safety recommendations or regulations that are directly related to blue light exposure. However, there are additional Occupational Safety and Health Administration regulations that require employers to protect their employees from potentially injurious light radiation. Unfortunately, it is not readily evident that these regulations apply to the excessive exposure to blue light. Consequently employers and dental personnel may be unaware that these Occupational Safety and Health Administration regulations exist.

Effect of Photodynamic Therapy on Multispecies Biofilms, Including Streptococcus mutans, Lactobacillus casei, and Candida albicans.

Objective: The aim of this study was to evaluate the effect of photodynamic therapy (PDT) on multispecies oral caries biofilms composed of Streptococcus mutans, Lactobacillus casei, and Candida albicans. Background: The abovementioned microorganisms largely cause dental caries, especially early childhood caries (ECC), by synthesizing of acids in the presence of sugar. PDT is considered an effective process to remove oral biofilms, and erythrosine, an oral bacterial disclosing agent, is an ideal dye that can be used as a photosensitizer in PDT. However, until now, there are no studies that have reported the effect of erythrosine-mediated PDT on biofilms, including the three microorganisms. Methods: The biofilms were formed on hydroxyapatite discs, and erythrosine was used as the photosensitizer, diluted to a concentration of 40 μM for 3 min. Light was irradiated for 10 and 20 sec using a blue light-emitting diode dental curing light. After the experiment, the colony-forming units of each microbial group cultured on blood agar plates were counted, and a confocal laser-scanning microscope was used to evaluate the effect of PDT. Results: The counts of all three microorganisms significantly decreased in the PDT group compared with those in the control group. For S. mutans and L. casei, there was a larger decrease proportional to the amount of energy irradiated. Conclusions: Overall, PDT showed a significant antimicrobial effect against oral biofilms composed of the three microorganisms, suggesting its potential clinical application for infants with ECC.

Evaluation of the Effectiveness of Dental Curing Light in Dental Offices Located in Karaj in 2016

Evaluation of the Effectiveness of Dental Curing Light in Dental Offices Located in Karaj in 2016

Effect of indirect restorative material and thickness on light transmission at different wavelengths

PurposeThe aim of this study was to evaluate the influence of indirect restorative material type and thickness on the transmission of different wavelengths from a broad-banded dental curing light. MethodsFour dental indirect restorative materials for computer-aided design and computer-aided manufacturing (CAD/CAM) were evaluated: [RC] resin/ceramic hybrid material (Lava Ultimate), [FC] feldspathic ceramic (VitaBlocs), and two zirconia-based ceramics ([ZK] Katana; and [ZL] Lava). Total loss of irradiance (TL) was measured for blue (WB, 425–490nm) and violet (WV, 350–425nm) wavelengths. Specimens of 15×15mm with varying thicknesses (0.5, 1.0, 1.5, and 2.0mm) were fabricated (n=5). A plasma-arc dental light-curing unit was used (Arc Light-II). To assess TL as a function of wavelength, a software (Spectra Suite v5.1) connected to a spectroradiometer (USB2000) and an integrating sphere (CTSM-LSM-60-SF) was used. Data was subjected to statistical analysis (two-way ANOVA and post-hoc Tukey test, α=0.05). ResultsA 0.5mm interposition resulted in TL from 50.5 to 67.2%, depending on material. Increased thickness resulted in higher TL for all materials. FC showed less TL compared to ZK. In general, WV showed higher TL than did WB, and WV/WB proportion decreased with increasing thickness. ConclusionsIndirect materials significantly reduced TL, and this effect is greater with increasing thickness. WV showed lower penetration compared to WB.

Effect of Combining Erythrosine with a High-Power Dental Curing Light Appliance on the Viability of a Planktonic Culture of Streptococcus mutans.

Objective: The aim of this in vitro study was to evaluate the effectiveness of antimicrobial photodynamic therapy (aPDT) composed of the association of the photosensitizer (PS) erythrosine irradiated by a high-intensity dental light source against a culture of Streptococcus mutans, comparing this effect with that of a 0.12% chlorhexidine solution. Materials and methods: For this purpose, planktonic suspensions of S. mutans were subjected to experimental conditions in which three different concentrations of erythrosine (E) (2, 4, and 8 μM) associated with three different doses emitted by the light source (L) (48, 96, and 144 J/cm2) were crossed, corresponding to the exposure times of 40, 80, and 120 sec, respectively, delivered in pulsed mode. The following experimental conditions were evaluated: G1-treatment with dye and light source (E+L+); G2-treatment with the dye only (E+L-); G3-treatment with the light source only (E-L+); G4-absence of dye and light (negative control); and G5-0.12% chlorhexidine (positive control). After treatment, aliquots of each group were plated on blood agar, then the colony forming units per milliliter (CFU/mL) later counted. The results were subjected to ANOVA and Tukey tests, considering the level of significance of 5%. Results: Group aPDT showed complete eradication of microorganisms as from the concentration of 4 μM irradiated for 40 sec, demonstrating statistically significant difference in comparison with the negative control group (p ≤ 0.05) and efficacy similar to that of the 0.12% chlorhexidine group (p ≥ 0.05). Conclusions: The authors concluded that the light-polymerizing appliance used in pulsed mode, associated with the PS erythrosine, was efficient for the control of S. mutans in a planktonic suspension in a short period of irradiation time.

Photopolymerization of cell-laden gelatin methacryloyl hydrogels using a dental curing light for regenerative dentistry

Photopolymerized hydrogels, such as gelatin methacryloyl (GelMA), have desirable biological and mechanical characteristics for a range of tissue engineering applications. ObjectiveThis study aimed to optimize a new method to photopolymerize GelMA using a dental curing light (DL). MethodsLithium acylphosphinate photo-initiator (LAP, 0.05, 0.067, 0.1% w/v) was evaluated for its ability to polymerize GelMA hydrogel precursors (10% w/v) encapsulated with odontoblast-like cells (OD21). Different irradiances (1650, 2300 and 3700mW/cm2) and photo-curing times (5–20s) were tested, and compared against the parameters typically used in UV light photopolymerization (45mW/cm2, 0.1% w/v Irgacure 2959 as photoinitiator). Physical and mechanical properties of the photopolymerized GelMA hydrogels were determined. Cell viability was assessed using a live and dead assay kit. ResultsComparing DL and UV polymerization methods, the DL method photopolymerized GelMA precursor faster and presented larger pore size than the UV polymerization method. The live and dead assay showed more than 80% of cells were viable when hydrogels were photopolymerized with the different DL irradiances. However, the cell viability decreased when the exposure time was increased to 20s using the 1650mW/cm2 intensity, and when the LAP concentration was increased from 0.05 to 0.1%. Both DL and UV photocrosslinked hydrogels supported a high percentage of cell viability and enabled fabrication of micropatterns using a photolithography microfabrication technique. SignificanceThe proposed method to photopolymerize GelMA cell-laden hydrogels using a dental curing light is effective and represents an important step towards the establishment of chair-side procedures in regenerative dentistry.

Ophthalmologic examination in dental school students and its relationship with the use of dental curing light

Objective: We determined the ophthalmic diagnostic of dental students at the University del Valle (Cali, Colombia), and compared the findings of ophthalmologic evaluation in a group of students previously exposed to the use of the curing light in clinical practice, and other group of students not exposed to it.&#x0D; Methods: It was implemented a survey by interview to report possible diseases, accidents and variables related to ocular pathology, including the use of curing lamp. Additional to this, it was performed an electroretinography, a photograph of eye fundus and a complete ophthalmological examination to each student.&#x0D; Results: It was not found a statistically significant association between injury and exposure to the lamp, but there was a trend towards a higher percentage of ninth-semester students who presented some kind of ocular pathology, compared with students coursing fifth semester.&#x0D; Conclusion: It is important to continue promoting and increasing knowledge about biosafety standards in dental students, dentists, assistants and patients, and give continuity to interdisciplinary work like this, which worked in a complementary manner with ophthalmologists. Further studies are recommended in the same population, after a period longer than two years.

Nanoparticle-Based Targeting and Detection of Microcavities.

Although dental caries is the most prevalent oral disease worldwide, currently, many dentists continue to use the traditional mirror and probe (dental explorer) method of caries diagnosis. This method of caries detection has the drawback that it is often difficult to distinguish between active and inactive carious lesions. In this work, novel bio-based nanoparticles are developed to specifically detect active caries in vitro. The nanoparticles are made from a cationic fluorescein-labeled food-grade starch in order to fluoresce when illuminated by a standard dental curing light, and to degrade in the oral cavity into nontoxic compounds after detecting the active carious lesion. When exposed to extracted human teeth, cationic fluorescent (+5.8 ± 1.2 mV) nanoparticles (size 101 ± 56 nm) selectively illuminate active caries, but not the healthy tooth surface. Two-photon microscopy confirms the selective binding and accumulation of cationic fluorescent nanoparticles into microscopic carious pores in enamel. These novel nanoparticles provide a unique method to assist in the early diagnosis of active carious lesions with the potential to directly impact dental treatment.

Light output from six battery operated dental curing lights

Light Curing Units (LCUs) are used daily in almost every dental office to photocure resins, but because the light is so bright, the user is unable to tell visually if there are any differences between different LCUs. This study evaluated the light output from six dental LCUs: Elipar Deep Cure-S (3M ESPE), Bluephase G2 (Ivoclar Vivadent), Translux 2Wave (Heraeus Kulzer), Optilight Prime (Gnatus), Slim Blast (First Medica) and Led.B (Guilin Woodpecker) with a fully charged battery, after 50, and again after 100, 20second light exposures. For each situation, the radiant power was measured 10 times with a laboratory-grade power meter. Then, the emission spectrum was measured using a fiber-optic spectrometer followed by an analysis of the light beam profile. It was found there were significant differences in the LCU power and the irradiance values between the LCUs (p<0.01). The Optilight Prime and Slim Blast LCUs showed a significant reduction in light output after a 50 and 100 exposures, while Bluephase G2 exhibited a significant reduction only after 100 exposures (p<0.01). The Bluephase G2 and Translux 2Wave delivered an emission spectrum that had two distinct wavelength emission peaks. Only the Elipar Deep Cure-S and Bluephase G2 LCUs displayed homogeneous light beam profiles, the other LCUs exhibited highly non-homogeneous light beam profiles. It was concluded that contemporary LCUs could have very different light output characteristics. Both manufacturers and researchers should provide more information about the light output from LCUs.

The dental curing light: A potential health risk

ABSTRACTPowerful blue-light emitting dental curing lights are used in dental offices to photocure resins in the mouth. In addition, many dental personnel use magnification loupes. This study measured the effect of magnification loupes on the “blue light hazard” when the light from a dental curing light was reflected off a human tooth. Loupes with 3.5x magnification (Design for Vision, Carl Zeiss, and Quality Aspirator) and 2.5x magnification (Design for Vision and Quality Aspirator) were placed at the entrance of an integrating sphere connected to a spectrometer (USB 4000, Ocean Optics). A model with human teeth was placed 40 cm away and in line with this sphere. The light guide tip of a broad-spectrum Sapphire Plus (Den-Mat) curing light was positioned at a 45° angle from the facial surface of the central incisor. The spectral radiant power reflected from the teeth was recorded five times with the loupes over the entrance into the sphere. The maximum permissible cumulative exposure times in an 8-hr day were calculated using guidelines set by the ACGIH. It was concluded that at a 40 cm distance, the maximum permissible cumulative daily exposure time to light reflected from the tooth was approximately 11 min without loupes. The weighted blue irradiance values were significantly different for each brand of loupe (Fisher's PLSD p < 0.05) and were up to eight times greater at the pupil than when loupes were not used. However, since the linear dimensions of the resulting images would be 2.5 to 3.5x larger on the retina, the image area was increased by the square of the magnification and the effective blue light hazard was reduced compared to without the loupes. Thus, although using magnification loupes increased the irradiance received at the pupil, the maximum cumulative daily exposure time to reflected light was increased up to 28 min. Further studies are required to determine the ocular hazards of a focused stare when using magnification loupes and the effects of other curing lights used in the dental office.