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At least 271 records · Page 15Linked to original sources
PubMed2004

Bleaching efficacy of whitening agents activated by xenon lamp and 960-nm diode radiation.

OBJECTIVE: This in vitro study examines the efficacy of two different dental whitening agents, Opalescence Xtra and Opus White, by analyzing the change in color achieved by the treatment and the temperature increase induced in the pulpal chamber. BACKGROUND DATA: Bleaching techniques achieved significant advances with the use of coherent or incoherent radiation sources to activate the bleaching chemicals. METHODS: The bleaching agents, containing 35% of hydrogen peroxide, were stimulated with 0.9 W of xenon arc lamp and 0.9 W or 2 W of a 960-nm diode laser during 60 sec (0.9 W) and 30 sec (2 W) on 33 extracted human teeth. During irradiation, the temperature in the pulpal cavity was monitored. The color change was evaluated using the CIE L*a*b* color space measurement system. RESULTS: The treated groups showed an increase in color saturation (DeltaC*) of 3-32% and a change in whiteness (DeltaL*) of 0-8%. This study found that only some of the irradiated groups show statistically significant difference (p < 0.05) in the effectiveness of their treatment when compared to the control, whereas no significant statistical difference was obtained in between the irradiated groups. Temperature increase was 2-4 degrees C when using the xenon arc lamp, 2-8 degrees C and 4-12 degrees C when using the diode laser at 0.9 W and 2 W, respectively. CONCLUSIONS: The results of this study suggest that Opalescence Extra and Opus White are both effective to provide brighter teeth. However, according to the conditions used in this study, only the xenon arc lamp induced a safer temperature increase.

Body Temperature↗
PubMed2004

A comparative study of polymerization lamps to determine the degree of cure of composites using infrared spectroscopy.

The aim of this study was to compare polymerization lamps of various technologies (halogen, high performance halogen, xenon, i.e. plasma arc, as well as diode lamps) to determine the degree of polymerization of composite probes using Fourier-transform infrared (FTIR) spectroscopy. To observe the light-induced curing reaction under a bracket, an attenuated total reflection (ATR)-FTIR was used. The results showed that the recommended curing times for all the polymerization lamps tested were adequate for successful polymerization of the composite used (degree of conversion approximately 60 per cent, which did not exceed 66 per cent after longer curing times). However, even after very long curing times, delayed curing of the composite must be taken into consideration as there was a decrease of approximately 10 per cent in FTIR band intensities (1637 and 3104 cm(-1)). ATR-FTIR spectroscopy showed that when bonding brackets with materials cured by light, uncured areas remain in the centre of the lowest layer of the adhesive.

Acrylic Resins↗
PubMed1979

An accessory fill-in flash for the Nikon photo-slit lamp.

High-quality slit lamp photographs require a balance between slit beam exposure and exposure of surrounding ocular structures. Proper exposure of surrounding ocular structure is difficult to obtain with the Nikon photo-slit lamp. The purpose of this research was to design an accessory fill-in flash for this slit lamp, which would provide proper exposure of over all ocular structures. In addition, this paper describes the procedures used to obtain proper exposure values and provides an exposure table for this accessory flash unit.

Eye↗
PubMed2006

Shooting a film photo slit lamp into the digital age.

PURPOSE: The purpose of this study is to describe a method of taking a slit lamp initially designed for film photography and updating it to provide digital photographs. METHODS: A "how-to" guide is provided. RESULTS: Updating a Nikon FS-2 slit lamp is more economic than many practitioners may realize. By using what is already available on the market, a few steps can make a would-be dated instrument useful for many years to come. CONCLUSIONS: The upgrade to the Nikon FS-2 slit lamp is not only possible, but is able to functional well in the clinical setting and capture high-resolution photographs.

Diagnostic Techniques, Ophthalmological↗
PubMed2004

Wood's lamp employed as a provocative technique to identify pseudoseizures.

We present a case of a 12-year-old female who presented to the emergency department with ictal phenomena suggestive of pseudoseizures. A Wood's lamp was successfully employed to induce the stereotypic phenomena and thereby identify the ictal events as nonepileptiform. Use of the Wood's lamp has not previously been reported as a provocative stimulus to induce pseudoseizures. Given its noninvasive nature and ready availability, the Wood's lamp should be considered for identification of pseudoseizures.

Child↗
PubMed1994

Role of gene expression and protein synthesis of tyrosinase, TRP-1, lamp-1, and CD63 in UVB-induced melanogenesis in human melanomas.

Using melanotic cells (SK-MEL-23 and G361) and amelanotic cells (C32 and SK-MEL-24) of human melanoma, this study examined whether UV-B irradiation has a direct stimulatory effect on the expression of genes involved in melanogenesis. Our initial screening of methylthiazol tetrazolium (MTT)-formazan formation assay indicated a low dose of ultraviolet (UV)-B irradiation, 2.5 and 5.0 mJ/cm2, can metabolically stimulate these cells. Repeated exposure of UV-B at 5.0 mJ/cm2 for seven consecutive days resulted in increased tyrosinase activity and melanin synthesis in SK-MEL-23 and G361 cells, but not in C32 and SK-MEL-24 cells. On reverse-transcription-polymerase chain reaction and immunoprecipitation studies, the two melanotic cell lines exhibited upregulated expression of mRNA and antigenic epitopes of tyrosinase, tyrosinase-related protein (TRP-1; gp75/HMSA-5), and lysosomal membrane associated protein (Lamp-1). The amelanotic cell line, C32, expressed the tyrosinase gene and protein constitutively but revealed no active tyrosinase or melanin synthesis even after UV-B exposure. Another amelanotic cell line, SK-MEL-24, exhibited no expression of tyrosinase gene and protein before and after UV-B exposure and, therefore, no melanin synthesis. Both C32 and SK-MEL-24 showed no gene or protein expression of TRP-1 before or after UV exposure, but upregulation of the Lamp-1 gene and protein expressions after exposure. We conclude that tyrosinase is the key enzyme responsible for UVB-induced melanogenesis. Both TRP-1 and Lamp-1 act together in melanogenesis, TRP-1 being essential and necessary. There is no change in the expression of CD63 lysosomal membrane protein at either the mRNA or protein level.

Antigens, CD↗
PubMed1977

Localization of malanin pigmentation in the skin with Wood's lamp.

Examination of the skin or hair with Wood's lamp has long been used to aid in the clinical diagnosis of some cutaneous disorders. A new observation reported here illustrates that Wood's light can be used to determine the depth of melanin pigmentation in the skin: contrast in epidermal pigmentation is increased while contrast in dermal pigmentation is decreased under Wood's lamp illumination compared to ambient visible light. The principles underlying this phenomenon are discussed. Use of the Wood's lamp to localize abnormal melanin pigmentation in the skin can be a guide to clinical diagnosis of hypermelanosis.

Diagnosis, Differential↗
PubMed1989

Non-stereo fundus photography as a screening procedure for diabetic retinopathy among patients with type II diabetes. Compared with 60D enhanced slit-lamp examination.

The spectrum of diabetic retinopathy, the need for fundus screening and the evaluation of two presumptive screening methods, was investigated in a population based study among patients with type II diabetes. Retinal evaluation was performed in 86.9% of the known diabetic population. Background diabetic retinopathy was detected in 37.8%, pre-proliferative in 1.1% and proliferative retinopathy in 3.8%. Diabetic maculopathy was found in 24.3% of the patients. Laser therapy was considered in 11.4% of the patients due to diabetic retinopathy, and in 14.6% when venous occlusive diseases were included. Two methods, a slit-lamp observation enhanced by a 60D lens and reading from two non-stereo photographs of the posterior pole, were evaluated among 154 patients willing and mentally capable of being examined by either method. The sensitivity of the photographic method was 87/97% (right eye/left eye) when detecting background retinopathy and 81/80% for maculopathy versus 69/61% and 79/63%, respectively, with the slit-lamp method. The photographic method could be applied in 93% of the patients mentally capable of cooperation. Only 5 or 6 patients could be examined per hour with the 60D slit-lamp compared with 30-35 examined by reading retinal photographs. The photographic method is recommended as an easy and reliable screening device for diabetic retinopathy among patients with type II diabetes.

Adult↗
PubMed1989

Non-stereo photographic screening after panretinal photocoagulation for proliferative diabetic retinopathy. Compared with 60D enhanced slit-lamp examination.

135 patients treated with panretinal photocoagulation for proliferative diabetic retinopathy were examined in order to detect 7 specific fibrovascular lesions after treatment. Two presumptive methods for long-term follow-up were evaluated and compared, i.e. slit-lamp biomicroscopy enhanced by a 60 D lens and reading from two non-stereo photographs of the posterior pole. Two observers repeated their examinations with respective methods. Comparison of the methods with respect to detecting ability of the fibrovascular lesions showed no significant disagreement except in some eyes with fibrous tissue on the optic disc where new vessels were better detected with the slit-lamp method (P less than 0.001). There was no difference between the methods with respect to the intra- and inter-observer variability. Twenty to 30 patients could be diagnosed per hour with the photographic method compared to 5-6 patients with the slit-lamp. Two non-stereo photographs of the posterior pole can be recommended as a safe and time-saving method for objective documentation and long-time follow-up after panretinal photocoagulation for proliferative diabetic retinopathy.

Adult↗
PubMed1987

Phototherapy and dithranol treatment of psoriasis: new lamps for old.

The response of psoriasis to ultraviolet radiation and dithranol was compared with the response to dithranol alone in 24 patients. The difference in rate of response, measured as change in plaque thickness, and the difference in time to complete clearance of psoriasis between irradiated and non-irradiated forearm lesions was significantly greater for patients treated using fluorescent lamps with negligible ultraviolet C emission (Wolff Helarium) than for those patients treated with a medium pressure mercury arc lamp (p less than 0.01) or an array of fluorescent sunlamps (p less than 0.05). The difference in therapeutic response shows that ultraviolet B phototherapy is effective when used in combination with dithranol. Nevertheless, radiation sources with substantial ultraviolet C emission, such as the medium pressure mercury arc lamp most commonly used to treat psoriasis in the United Kingdom, have little effect because delivery of therapeutic doses of ultraviolet B is limited by erythema induced by ultraviolet C.

Adolescent↗
PubMed1988

Fluorescent lights, ultraviolet lamps, and risk of cutaneous melanoma.

Exposure to solar radiation is increasingly being associated with a risk of cutaneous melanoma, and some risk has also been attributed to exposure to fluorescent lights. The risk of cutaneous melanoma associated with exposure to some sources of artificial ultraviolet radiation was examined in a case-control study in a Scottish population with fairly low exposure to natural ultraviolet radiation. The risk was not significantly or consistently raised for exposure to fluorescent lights at home or at work. The use of ultraviolet lamps and sunbeds, however, was associated with a significantly increased risk (relative risk = 2.9; 95% confidence interval 1.3 to 6.4), and the risk was significantly related to duration of use. The risk was particularly raised among people who have first used [corrected] ultraviolet beds or lamps more than [corrected] five years before presentation (relative risk = 9.1; 95% confidence intervals 2.0-40.6), in whom it was significantly related to cumulative hours of exposure. The risks associated with exposure to ultraviolet lamps and sunbeds remained significant after adjustment for other risk factors for melanoma.

Adolescent↗
PubMedDate not supplied

Pathogen control in complex fluids with water-coupled excimer lamps at 282 and 308 nm.

Water-coupled excimer lamp systems have been developed to inactivate microorganisms within complex, low-optical quality, fluids. Monochromatic lamps were selected to minimize UV-B and UV-C absorption within the carrier fluids while maximizing deposition within specific chemical targets. Fundamentals, system scaling and power supply design are discussed. This work used two large-surface area excimer lamps as intense sources of near monochromatic radiation at 308 and 282 nm. Data are presented for two distinct fluid systems: flow-through processing of large-volume metalworking fluids used in heavy industry and batch irradiation of human blood plasma and platelet suspensions used in transfusion medicine. In the first, a 200-600 L/min reactor is used to control bacterial concentrations within metalworking fluids used in large-scale metal machining processes. Control is defined as the maintenance of 10(3) to 10(4) CFU/mL in fluids that without treatment would have concentrations over 10(7) CFU/mL. The second is a batch process for viral inactivation in undiluted blood bank products. Samples of fresh frozen plasma and platelet suspensions were spiked with high titers of porcine parvovirus (PPV) and irradiated at 308 and 282 nm. Although both wavelengths were effective at reducing PPV levels, 308 nm light resulted in both higher rates of viral inactivation (greater than 6 log units) and lower rates of fluid degradation.

Animals↗
PubMed2000

[Slit-lamp laser photocoagulation with a quadraspheric contact lens for the treatment of retinopathy of prematurity].

PURPOSE: To present our experience of slit-lamp laser photocoagulation with a pediatric quadraspheric contact lens for the treatment of retinopathy of prematurity (ROP). MATERIAL AND METHODS: 8 eyes of 4 premature babies with threshold ROP were consecutively treated under general anesthesia by means of blue-green argon laser photocoagulation delivered through a table mounted slit-lamp and a wide field contact lens specially designed for infants. Three of the treated eyes had a zone I disease, 2 a posterior zone II disease and 3 a zone II disease. Mean follow-up was 13 months. RESULTS: Early complete regression of the neovascular proliferations and plus disease was observed in all the treated eyes (100%) without apparent sequela. In only one eye that had zone I disease a mild and small peripheral vitreous hemorrhage was observed. Neither cataract nor posterior synechia was observed. A discrete and transient badly hypothermia occurred only in one case. COMMENTS AND CONCLUSIONS: This study shows the efficacy and precision of slit-lamp argon laser photocoagulation through a quadraspheric contact lens in ROP, with a very low rate of complications, and with a magnificent and comfortable visualization of all the structures to be treated. Each retinal burn was easily and very precisely placed from the ridge to the ora serrata in 360 with only a slight to moderate tilting of the wide field lens and without the need of scleral depression.

Gestational Age↗
PubMed2002

Occupational risk from ultraviolet germicidal irradiation (UVGI) lamps.

The recommended role of ultraviolet germicidal irradiation (UVGI) is to reduce the risk of tuberculosis (TB) transmission in health care facilities. However, excess exposure may result in dermatosis and photokeratitis. In one hospital setting in Botswana, two nurses and one housekeeper complained of eye discomfort, 'like sand in the eyes', after working in an administrative office. The following day, one employee noted facial skin peeling. All symptoms resolved over 2-4 days without sequelae. Six weeks later, the syndrome recurred for all three employees. A workplace investigation revealed that the office had been converted from a hospital sputum induction room, and that an unshielded 36-W UVGI lamp was still installed and operational. The on/off switch for the UVGI lamp was immediately adjacent to the fluorescent bulb on/off switch, and did not have a locking mechanism. The US National Institute for Occupational Safety and Health recommends that exposure to UVGI (254 nm) be less than 6000 microJ/cm2 (6000 microW approximately = sec/cm2) over a daily 8-hour period on unprotected skin or eyes. In the office, UVGI measurements at eye level and looking directly at the UVGI lamp ranged from a low of 20.0 microW approximately = sec/cm2 when seated to a high of 49.9 microW approximately = sec/cm2 when standing. These irradiance levels result in allowable exposure times of 300 and 120 seconds, respectively, and are the most likely cause of the clinical syndrome described.

Disinfection↗
PubMed2003

[Rapid and simple detection of Legionella species by LAMP, a mew DNA amplification method].

Legionella is a common cause of community-acquired respiratory tract infections and occasionally causes nosocomial pneumonia. Rapid and accurate detection of legionellae is important for diagnosis and treatment of patients. In order to detect legionellae, a new DNA amplification method was designed and evaluated. Loop-mediated isothermal amplification (LAMP) method amplifies DNA with high specificity, sensitivity, and rapidity under isothermal conditions at 65 degrees C. This method employs a DNA polymerase with strand displacement activity and a set of four specially designed primers that recognize a total of six distinct sequences on the target DNA. The primers targeting 16S rRNA gene were designed in order to detect a wide range of Legionella species. We could specifically detect Legionella species including Legionella pneumophila, Legionella anisa, Legionella bozemanii, Legionella dumoffii, Legionella erythra, Legionella feeleii, Legionella gormanii, Legionella longbeachae, Legionella micdadei, Legionella oakridgensis, and Legionella sainthelensi. The detection limit of the assay was 6 cfu per test of L. pneumophila strain. Furthermore, all of the positive LAMP results could be obtained within 50 minutes. The LAMP method was able to detect a wide range of Legionella species with high specificity, sensitivity, rapidity, and a simple procedure.

Legionella↗
PubMed2004

Role of light emitted by incandescent or fluorescent lamps in the development of myopia and astigmatism.

BACKGROUND: The purpose of our study was to determine if the development of refractive errors night be associated with exposure to light emitted by incandescent or fluorescent lamps. MATERIAL/METHODS: 3377 students from elementary schools, junior high schools and high schools were examined, aged 6-19 years. Visual acuity was measured, and retinoscopy was performed after cycloplegia. The parents of all students examined completed a questionnaire concerning the child's exposure to light emitted by incandescent or fluorescent lamps before the age of two. The data was analyzed using the chi-squared test. RESULTS: Sleeping till the age of two with a room light turned on leads to an increase in the occurrence of myopia (P<0.01). It was also found that light emitted by fluorescent lamps leads to more frequent occurrence of astigmatism (P<0.01). CONCLUSIONS: Disturbance of the daily light/dark cycle over the time during which refraction develops may disrupt emmetropization and lead to refractive errors.

Adolescent↗
PubMed2004

Temperature rise in the pulp chamber induced by a conventional halogen light-curing source and a plasma arc lamp.

PURPOSE: To assess and compare the pulp chamber temperature increase during resin-based composite polymerization with two different light-curing units. METHODS: A Class I cavity was prepared in an extracted lower molar under standardized conditions using a specially designed industrial robot system. The dentin layer between the pulp chamber and the floor of the cavity was 1 mm thick. Pulp chamber temperature rises (starting temperature: 20.0 +/- 0.1 degrees C) were recorded for four different series of investigations using both the halogen curing lamp Elipar Visio (light-curing: 40 s) and the plasma arc lamp Apollo 95E (light-curing: 3 seconds): Group A: Operation of the light-curing units directly over the untreated, empty cavity; Group B: Resin-based composite polymerization without previously applied cement base or bonding agent; Group C: Resin-based composite polymerization with a previously applied cement base; Group D: Resin-based composite polymerization with a previously applied bonding agent. In each of the four groups 10 measurements were carried out for every light-curing unit. Data were statistically analyzed using ANOVA, post-hoc Scheffé test and t-test. RESULTS: The lowest temperature increase (0.3 degrees C) was recorded during composite polymerization with a previously applied cement base using the Apollo 95E unit (Group C, P < 0.05). The highest temperature increase was induced when using the Elipar Visio unit directly over the untreated cavity (Group A, P < 0.05). In Groups A, C and D higher pulp chamber temperature measurements were obtained when using the Elipar Visio unit as compared to the Apollo 95E plasma arc lamp (P < 0.01). In Group B, no significant differences were recorded during the composite polymerization when using the two different light-curing units (P > 0.05).

Analysis of Variance↗
PubMed2005

Clinical evaluation of a novel dental whitening lamp and light-catalyzed peroxide gel.

OBJECTIVE: This study examined whether an ultraviolet light enhanced the whitening efficacy of a peroxide gel containing a photo-Fenton activator. METHODOLOGY: Fifty subjects were enrolled into the trial at two geographically separate sites. As directed by the randomization keys, teeth of half of the study subjects were concurrently exposed to the whitening lamp, while the gel was on their teeth, for a total light exposure of 45 minutes. The other half of the subjects received no light treatment. At each examination, clinical data were collected on the gingival index, shade score, and self-assessed dentinal hypersensitivity. RESULTS: Changes in tooth shade were significantly better (approximately 26% improvement; p < 0.05) for subjects exposed to the gel and dental whitening lamp (average = 7.7 shade changes) compared to subjects exposed to the gel only (average 6.1 shades) immediately after treatment. No reports of erythema, desquamation, ulceration of soft tissues, gross changes in teeth, gingiva, or restorations were documented. The relative changes in mean sensitivity scores were similar for both groups, with no significant differences between the Light and No-light groups at any interval. CONCLUSION: The whitening effect was improved by approximately 26% when the Zoom2 dental whitening lamp was used. It was demonstrated that the a photo-Fenton activator used with a bleaching light and 20% hydrogen peroxide gel is safe and effective for whitening teeth rapidly.

Adolescent↗