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Lasers have been used in dif- ferent medical fields for many years and have revolutionised many treatments, notably eye surgery and hair removal. The technology is also an estab- lished aspect of modern den- tistry and is widely used in Europe and the USA. DTI edi- tor Anke Schiemann had a chance to speak to Graeme Milicich, who is a fellow, diplo- mate, and founding board member of the World Congress of Minimally Invasive Den- tistry (WCMID), prior to the recent FDI Congress in Stock- holm in Sweden. Anke Schiemann: In a nutshell, what are the ben- efits of using laser in clini- cal dentistry today? Graeme Milicich: Lasers have many applications in clinical dentistry. My re- search in the last four years fo- cused on the clinical applica- tions of hard tissue Erbium lasers. The broad range of laser applications has bene- fits for both the patient and the dentist. Many hard and soft tissue laser treatments are much less invasive com- pared with conventional ap- proaches. I do not think there is another piece of technology in dentistry that has the abil- ity Erbium lasers have to treat soft tissue, bone, and tooth structure, simply by changing laser-operating parameters. What is the advantage of lasers over rotary cutting instruments, and are there limitstowhatalasercando? Yes, there are some limita- tions as to what can be done with a laser, like the removal of metal restorations and crowns. But if you consider the totality of the types of treatments offered by general dentists, these limitations are far less compared to con- ventional rotary instrumenta- tion. For example, you could run into problems with soft tissue contours or bone levels associated with a deep cavity while cutting tooth structure. With a laser you can remove both bone and soft tissue by simply changing a setting, and are therefore able to complete the procedure in one appoint- ment—something that cannot really be done with a high- speed drill. Generally speak- ing, what can be done with a drill, scalpel, or bone bur can also be done with a laser. Ad- ditionally,manypatientshave a fear of dentistry based on the sounds and vibrations as- sociated with rotary instru- ments. These sensations do notoccurwiththelaser,mean- ing the patients find treat- ment much more acceptable. What role does laser flu- orescence detection cur- rently play in the preven- tion of oral diseases? WiththeadventoftheKaVo DIAGNOdent more than ten years ago, the first general dentistry application of laser fluorescence was introduced. Like with any new technology, it had to be understood first, in order to achieve the best results. In order to provide patients with accurate treatment rec- ommendations based on the results of early cavity detec- tion, an understanding of min- imally invasive concepts is es- sential. Otherwise, the profes- sion can be open to claims of over treatment. These charges often derive from a lack of understanding of the technol- ogy, its accurate application, and the concepts and applica- tions of minimally invasive techniques. Often, astute cli- nicians are at the forefront of the application of new tech- nology and techniques, and the research literature strug- gles to keep up with the clin- ical pioneers. This leads to aperiodwithashortageofval- idation for what eventually becomes a new and accepted standard of care. Further de- velopments in the field are occurring and, as they filter into general practice, the standards of diagnosis will continue to improve. For new diagnostic technology to be readily implemented in gen- eral practice, it has to be both cost effective and time effi- cient. What are the chances of treating peri-implantitis with lasers? There are many case stud- ies showing excellent results when treating peri-implanti- tis with a laser. The laser’s use for debridement and disinfec- tion gives the competent clini- cian a tool that previously wasn’t available. The laser is safe to use around implants with little risk of damage to the implant. Personally, I have only treated one case of peri- implantitis so far, and it was a complete success. The use of laser in fields like endodontics or peri- odontology is highly con- troversial. What are the main issues here? Once again, competent la- ser clinicians are ahead of the research in these fields. Clini- cal results are being achieved that are now only beginning to be validated by research, and until the research results are available, use of lasers in these fields is going to remain controversial for many. Those that are using lasers and are observing the clinical out- comes, have little doubt as to the efficacy of their treat- ments. Personally, I have been involved in research using the Waterlase (Er,Cr:YSGG) in endodontics. The ability for complete debridement of the canals following conventional canal preparation using radial firing tips in a non-ablative mode is significant, and ad- dresses the issues of air and fluid entrapment at the apex that are associated with con- ventional techniques used for final canal debridement and rinsing. In your FDI lecture you talked about new concepts associated with laser ther- apy. Can you give our read- ers a brief overview and ex- plain these concepts? The most common com- plaint from a new user is that it will not cut fast enough. The most significant contributor to slow ablation rates is the user, not the technology. The single biggest hurdle a dentist faces when beginning with laser is the difference be- tween rotary instrumentation and lasers. When this is un- derstood, a new laser dentist can become competent in a very short time. If these con- cepts are not well taught, then thenewuserwillbecomefrus- trated and may fail to inte- gratetheirnewlaserintotheir treatment regimes. The first concept is that la- sers are end cutting. We have all become very competent using rotary instrumentation and have developed reflex motions as a result. The natu- ral tendency is to apply these ‘reflexes’ when using a laser and this leads to frustration for the new user. When using a high-speed bur, we tend to move the bur laterally to ex- tend a cut. This does not work with a laser because it is end cutting, not side cutting. Therefore, the operator needs to learn a new way of pointing the laser directly in the direc- tion where a cut needs to be extended.Anyonewhohasbe- come competent in the use of airabrasionmasterstheuseof a laser very quickly because the same concepts apply to both technologies. The second concept is that slow is fast. Once again, this concept is associated with our reflex motions associated with using high-speed hand pieces. We tend to use a fast painting motion on the sur- facewhencontouringacavity. Exactly the opposite applies when using a laser. Ablation rates are stalled by this rapid painting motion, and initially it requires a mental aware- ness to slow the motion of the tip, to allow ablation to occur. As competence increases, this phenomenon is used to con- trol ablation rates, without having to alter laser settings, by increasing or decreasing the motion of the tip. The third concept is focus- ing and defocusing the beam, to alter ablation rates without having to change power set- tings on the laser. This tech- nique, in combination with slowing or speeding up the motion of the tip, allows the operator to finesse ablation rates to create very smooth contours. The final concept is the clinically observable ablation threshold. Many new users fo- cusonpowersettingsandhow far the tip should be from the surface, depending on what they want to do. Absolute dis- tances in relation to operating parameters are impossible to give because there are so many variables involved, in- cluding the tip being used, the state of the tip, the air/water ratios, and the surface being ablated. As a tip is moved to- wards the tooth, it reaches a point where the operator can begin to see the com- mencement of ablation. This then gives a reference maxi- mum operating distance in re- lation to the current settings and tip being used. New users are taught to start out of focus and move towards the tooth until the clinically observable ablation threshold is reached. This distance can range over several millimetres, depend- ing on the various parame- ters. Understanding the con- cept helps new users avoid in- advertent high fluence effects at the ablation surface. There are two other issues that will be dealt with as sep- arate topics in the lecture in regard to ablation rates in enamel. This is the area that new users find most frustrat- ing, because they tend to use rotary cutting movements with an end-cutting device. Firstly, because laser ablation is a non-contact technique, magnification is essential. Se- condly, enamel ablation rates are related to the orientation of the long axis of the enamel prisms in relation to the plane of the ablation face. Ablation rates are 40 per cent greater when enamel prisms are ab- lated from their sides, rather then on their ends. This re- quires an understanding of the orientation of the long axis of enamel prisms in dif- ferent surfaces of a tooth. The culmination of this under- standing is epitomised in the time it takes a new user or a competent laser clinician to cut a slot preparation, with a new user often taking more than three times as long to complete the same proce- dure. Recent research on shor- terwavelengthlasersorthe so-called blue lasers has shown them to be effective in diagnosing cancer cells. With this in mind, how do you see the use of the laser in general dental practice developing in the years to come? Many dentists focused on minimal intervention have embraced laser fluorescence in the diagnosis of demine- ralisation of tooth structure. With these new applications, such cancer screening be- comes cost effective and will become a common part of gen- eral dentistry. The main issue is that laser effects are fre- quency specific, and as appli- cations develop, this will lead to a plethora of technology that becomes difficult for the clinician to incorporate into a practice. I envisage, in the near future, a diode-based laser that will have multiple, switchable frequencies that will allow one unit to accom- plishvariedtasksthatrequire different frequencies. As up- take of laser technology in- creases, costs will decrease, making it more attractive to more of the profession. Do you expect lasers to be an essential part in every dental practice in 10 to 15 years? The multiple applications of lasers are only going to ex- pand in the future. At the mo- ment, the lasers with the most clinical applications in one unit are the Erbium family, and many dentists have em- braced this technology and are constantly expanding its clinical applications. If we look back over 60 years to the initial introduction of the high-speed hand piece, there was initial and significant re- sistance to the technology, and it took over 10 years be- fore it was readily accepted into general practice. Lasers have had a slower journey, mainlybecauseoftheneedfor advanced technology to make them more applicable in the field of dentistry and the asso- ciated research and develop- ment costs that are reflected in the price of lasers. Taking the cost of a laser out of the equation, it is very easy to vi- sualise a laser in every prac- tice in the near future. Thank you very much for the interview. IDEM10 113x213mm FDO Final Programme Ad.ai 8/8/08 5:39:20 PM AD “The applications of lasers are only going to expand” Interview with Graeme Milicich,New Zealand Graeme Milicich (DTI/Creation/Shafeev) trends10 Show Preview IDS Cologne 2009