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Dental Tribune Nordic Edition | 3/201514 TRENDS&APPLICATIONS All dentists are familiar with the composite curing lamp. Some may not use it in their clinical work, like oralsurgeons,buteveryonehasseen and used one. Most current curing lightsarebaseduponlight-emitting diodes (LEDs). This blue light has a centre wavelength of around 460 nm and the power density is around 1,000 mW/cm2. The output power is typically 200–250 mW. Light is capable of many things and a curing light achieves more than curing of composites and cements. In 2008, Enwemeka et al. published a study showing that blue light at 405 nm could effi- ciently kill strains of methicillin- resistant Staphylococcus aureus (MRSA) in vitro.1 However, there may be safety concerns in clinical practice regarding the 390–420 nm spectral width of the 405 nm LED source owing to the trace of ultraviolet light within the spec- trum.Therefore,in2009,thesame researchers published a similar experiment,2 but using an LED withacentrewavelengthof470nm. They found that this wavelength wasjustaseffective:anenergyden- sity of 55 J/cm2 killed over 90 per cent of the MRSA. This wavelength seems familiar because we have it in our curing lamps. Since 405 and 470 nm produced similar results, the choice of blue wavelength does not appear to be crucial. In everyday dentistry, we do not see many cases of MRSA, but should still be aware of the potent tool at our disposal if such cases arise.However,whatwedoseedaily is dental plaque, and it is full of bacteria. So, could the curing light be used to reduce dental plaque? Using the curing light to reduce dental plaque seems a bit impracti- cal, but it is an idea for innovative productsinthenearfuture.Aprod- uctwiththeshapeofanimpression tray emitting blue light could be quite practical and could be com- bined with red light, for tissue bio- stimulation.Toothbrushesthatuse bluelightarealreadyonthemarket. In Soukos et al.,3 the 11 study sub- jectsrefrainedfrombrushingtheir teeth for three days. One side of the dental arch was irradiated with blue light at 455 nm with a power density of 70 mW/cm2 twice a day for four days. On the fourth day, plaque was collected from both sides and analysed by checkerboard DNA probe analysis of 40 perio- dontal bacteria. Porphyromonas gingivalis and Prevotella interme- dia were significantly reduced on the irradiated side by 25 and 56 per cent, respectively, compared with the non-irradiated side. Five other species were identified as being sensitive to this irradiation. Fur- ther, there was a slight decrease of gingival redness on the irradiated side, whereas there was a slight in- crease on the non-irradiated side. Fontana et al.4 exposed cultures of eight bacteria to blue light at 455 nm with a power density of 80 mW/cm2 and an energy density of 4.8 J/cm2 . Human dental plaque bacteria were also exposed once to blue light with a power density of 50 mW/cm2 and an energy density of 12 J/cm2 . In order to study the cumulative effect of phototherapy on the eight previously identified photosensitive pathogens and on biofilm growth, microbial biofilms developed from the same plaque were irradiated with blue light at 455 nm with a power density of 50 mW/cm2 once a day for 4 min- utes (12 J/cm2 ) for three days and four exposures. The photo-target- ing effect was studied using whole genomic probes in the checker- board DNA–DNA format. In cul- tures, all eight species showed significant growth reduction. After irradiation, the mean survival was reducedby28.5and48.2percentin plaque suspensions and biofilms, respectively. DNA probe analysis showed significant reduction in relative abundances of the eight bacteria as a group in plaque sus- pensions and biofilms. The cumu- lative blue light treatment sup- pressed biofilm growth in vitro. Whatelsecouldacuringlightdo? Ishikawa et al.5 state that dental curing lamps can emit blue-violet wavelengths of around 380–515 nm with two peaks (410 and 470 nm). Thesewavelengthscoverthemaxi- mum absorption spectra of hae- moglobin (430 nm). So could it be used to improve the coagulation process after extractions? In ten cases, irradiation of the extraction socket was performed 1 mm from the socket with a power density of 750mW/cm2 andanenergydensity of7.5J/cm2 for10seconds.Bleeding was stopped by conventional roll pressure in another five cases as a control.Bleedingtimeforbothpro- cedures was measured. Irradiation withtheLEDresultedinimmediate haemostasis of the socket. Five cases showed coagulation within the first 10 seconds and another five cases required an additional 10 seconds to control the bleeding fully. In contrast, the roll pressure method required 120–300 seconds (median 180 seconds) to obtain haemostasis. One week later, the irradiated sockets had healed with epithelial covering. Transmission electron microscopy showed the formation of a thin amorphous layerandanadjacentagglutination of platelets and other cellular ele- ments under the layer at the inter- face of the irradiated blood. Okamoto et al.6 from the same group of researchers then went on to use a blue-violet LED in patients on warfarin who required tooth extraction. The patients were di- vided randomly into three groups. The first group was irradiated with blue LED after tooth extraction. The second group was treated with haemostatic gelatin sponges and LED irradiation. The third group was treated with only haemostatic gelatin sponges. Haemostasis was evaluated at 30 seconds after treat- ment. Less than 30 per cent of the patientsinthehaemostaticsponge group achieved haemostasis with- in30seconds,approximately50per cent of the patients in the simple LED irradiation group achieved haemostasis within 30 seconds, and 86.7 per cent of the patients in the LED and haemostatic sponge combined group achieved haemo- stasiswithin30seconds.Inconclu- sion, the additional use of the LED improved the effect of the haemo- static sponge. The studies by Enwemeka et al. and Ishikawa et al. stimulated my own curiosity, and I have used my curing light for several indications lately. A special case was an elderly malepatientwhohadsufferedfrom an MRSA infection on his scalp for about ten years. Every conceivable treatment had been tried, but in vain.Welaterdiscoveredthathehad beenwearingthesamecapformany years and thereby constantly re- infected himself. A combination of irradiationwiththecuringlightand ozone led to almost complete heal- ing. The first photograph shows the situationonthefirstday,thesecond photograph shows suppuration at the second session and the third photograph shows the situation at thelastsession. The power of the curing light is similar to that of a traditional low-level laser (200–250 mW). The “power”referredtoinLEDmanuals isactuallythepowerdensity,which is the output power in mW divided by the irradiated area. So if the output power is 250 mW and the tip of the probe is 0.25 cm2 , the powerdensityis250mW÷0.25cm2 = 1,000 mW/cm2 . There is a trend towards increas- ing the power of the curing light in ordertoshortenthetimenecessary to cure a filling. Rapid curing may or may not be optimal for the quality of the filling, but care should be taken not to let the high temperaturesharmthepulp.There are now curing lights with output in the W range and power densities of up to 5,000 mW/cm2 . Certainly fast curing, but what about the temperature rise? Runnacles et al.7 tested the temperature rise in hu- man premolars using different in- tensities from a standard curing light. All irradiations produced a higher peak temperature than the baseline temperature, with some teethexhibitingatemperaturerise of higher than 5.5 °C, an increase thought to be associated with pul- pal necrosis. Utilise the versatility of your curing light, but be careful not to harm the pulp. Editorialnote:Alistofreferencesisavail- able from the publisher. Anunknownphototherapeutictool Using the composite curing lamp in daily dental practice By Dr JanTunér,Sweden Dr Jan Tunér specialises in the field of laser phototherapy. He maintains a private practice in Grängesberg in Sweden and can be contacted at jan.tuner@ swipnet.se. Fig.1: Original situation after an MRSA infection on the scalp for about ten years.—Fig.2: Suppuration after two sessions.—Fig.3: Situation after ten sessions. “The power of the curing light is similar to that of a traditional low-level laser.” 1 2 3 DTNE0315_14_Tuner 02.11.15 11:06 Seite 1 123 DTNE0315_14_Tuner 02.11.1511:06 Seite 1