Written by Martin B. Goldstein, DMD Saturday, 31 July 2004 19:00
A few weeks ago, my dental partner and I were both preparing 8-unit veneer cases on opposite ends of the hall- "dueling veneers", if you will. Upon case completion, we inspected each other's provisionalization prior to the patients' departure-shrink-wrapped, 8-unit Luxatemp temporary veneers. During this brief visit, we "ooh'd" and "ah'd" to make the patient feel good, but we were, of course, interested in seeing each other's results. Later, during a relaxed lunch, my partner, a gifted dentist possessing an excellent set of hands, commented, "Both of our temps looked nice, but how come your soft tissue looked like it hadn't been touched (Figure 1a), and mine had the usual battle-scarred look?" (Figure 1b) He was referring to the small gingival nicks and scrapes that we as dentists have been accustomed to seeing when finishing restorative work in close proximity to the gingiva. At the end of his sentence, it occurred to me that since I upgraded my level of magnification, the days of battle-scarred gingiva had essentially passed. I offered this as an explanation. Apparently he bought it, because an hour later he was on the phone to my Orascoptic rep. It was time to retire his 2.5x loupes.
|Figure 1a. Gingiva remains untouched.||Figure 1b. Gingival scrapes and nicks.|
|Figure 2. Orascoptic's loupe classification system.||Figure 3. Compound loupes.|
|Figure 4. Prismatic lens components. (Photo courtesy of Dennis A. Shanelec, DDS.)||Figure 5. EyeMax class IV loupes.|
|Figure 6. A forced upright posture for a healthy back.||Figure 7. Low and high magnification compared.|
|Figure 8. Orascoptic Zeon light.||Figure 9. Few bleeders with high magnification.|
|Figure 10. Oblique coronal fracture more readily seen.||Figure 11. Higher magnification reveals defective amalgams|
A FEW TECHNICALITIES
If you are currently using loupes that are said to have 2x or 2.5x magnification (called class II magnification by Orascoptic), then you are employing compound loupes. Rather than using a single lens to increase magnification, multiple lenses are combined with intervening air spaces (Figure 2). They are typically said to have a "Galilean design" named after Galileo Galilei, the 17th century astronomer. Most of us currently using loupes were weaned on such systems. They are lightweight, relatively unobtrusive, and sold in both flip-up and through-the-lens designs (Figure 3).
I'll coin a phrase: "visual anxiety" or "VA." It's the subtle but omnipresent uneasiness felt by a dentist barely able to see what he or she is doing, hoping that sense of touch will bail him or her out of harm's way. Remember our credo "Do No Harm?" Harm equals nicking adjacent teeth; nicking gingival tissue, cheeks, and tongues; cutting too deep when removing amalgam; leaving a finish line that looks like the steps of the Lincoln Memorial...the list is long. But the profession falls prey to VA daily, owing to the type of environment that we've chosen to work in: wet, dark, and distant. VA is stressful. It erodes our confidence. It tires us too early in the day.
Moving Along: You Don't Know What You Don't Know
What follows is an accounting of several practical benefits that this author encountered upon embracing a higher-powered prismatic system-little things, but unexpected and pleasant to experience.
Take a peek at Figure 9. Notice how the syringe tip has been placed in the "bare" area amidst a web of arterioles and capillaries. The result? Far fewer bleeders than before. This is particularly true when administering the relatively shallow injections in the anterior maxilla. I tear fewer vessels when I am able to visualize needle placement clearly. The other benefit is also unexpected but notable. The zoomed-in view "crops" out your patients' grimaces and scrunching eyes (even if they are not really in pain), allowing you to concentrate on the injection process and feel less like an agent of torture.
Certainly the benefits noted here apply to most indirect restorative techniques, but as was noted in the anecdote in the introduction, bur control is particularly important when preparing anterior veneer preps and finishing provisionals. It's equally important when removing shrink-wrapped provisionals because bleeding tissue will slow the cementation procedure considerably. The ability to section resin temps accurately that hug gingival tissue without concomitantly slicing the adjacent tissue is a "must-have."
Crown and Bridge
The most notable change you will encounter upon stepping up to higher magnification will be the improved continuity of your finish lines (provided you dry your preps upon "near final" inspection). The sins resultant from interrupted diamond contact with the tooth will become apparent, as will scattered, unsupported shards of enamel extending beyond a typical chamfered or shouldered finish line. You will feel compelled to correct these issues by joining discontinuous segments of finish line and shaving off exogenous enamel shelves. Your labs will thank you for it. You will also be grateful at cementation time since the unsupported enamel would have quickly broken off the cast at die trim time, creating an ill-fitting crown. The final product, having been a product of better quality control on your part, will go to place with far fewer hitches. Additionally, you'll be less apt to scrimp on interocclusal space because you'll better visualize the space you've created. This translates to fewer "spot the opposing, doc" notes from your lab.
Today's enlightened endodontist typically features a surgical microscope such as those marketed by Global and Zeiss, to name a few. They've proven invaluable. I had the pleasure of using one on loan from Global for more than a month and came to recognize its value not only for endodontic purposes but for restorative dentistry as a whole. The wonderful magnification, resolution, and 3-D view would appear to be a perfect fit for dentistry, but there is a tradeoff-mobility. The practitioner must learn to sit still and more or less move the subject around the position and viewing axis of the microscope. Certainly, the scope is maneuverable, but not as much as a set of high-powered loupes perched on your nose; and it is certainly more cumbersome to maneuver when in the midst of doing a prep and needing to see a section of a tooth that is blocked out by an adjacent tooth. With high-powereds, you simply move or tilt your head and line up your view; with a scope you stop what you're doing, reposition the scope, the patient's head, or the operating chair, and continue. In light of this, it's easy to see why endodontics is such a good fit for a surgical scope. Typically, one can work in one view and see all that needs to be seen for the entirety of the procedure, changing only the depth of focus.
This area is fairly obvious but deserves mention. Consider the ubiquitous intracoronal fracture, particularly the ones located underneath a cusp, exposed when an amalgam is removed. When stained by corrosive products and microleakage, they are fairly easy to see, even with the naked eye. The ones that aren't stained, however, are a challenge to see and diagnose. To beat the dead horse, class IV high magnification and a headlight will make it happen for you. Couple your finding with a digital photo enlarged and on a 17-inch monitor in front of your patient, and your recommendations approach gospel status (Figure 10).
PERIODONTICS AND PREVENTION
Periodontists, you're probably already there. How can periodontal surgery not benefit from increased magnification? As Forrest Gump would say, like "peas and carrots," particularly with the vast numbers of implants being sewn by the subspeciality. I'd propose, however, that the prime benefactor of a higher-powered view would be the advanced dental hygienist, entrusted to root plane and scale and/or conduct a soft-tissue management regimen effectively. I sheepishly admit that I often feel like I have an unfair advantage when inspecting my hygienist's efforts under high magnification when they've been toiling away with 2x, or worse yet, no magnification. Also consider their ability to pick up defective restorations and subtle signs of coronal fracture. Again, the benefits are obvious.
IT'S NOT ALL ROSES
While the glory of high magnification is undeniable, take the following into account:
(1) They are more expensive than your 2 and 2.5s (more complexity, more cost).
(2) They take longer to get used to. (It took me 2 to 3 weeks of switching back and forth before putting my 2.5s to rest on a shelf.)
(3) Due to the reduced light allowed in, a head light is recommended.
(4) Once you use them for an extended period, you will become dependent on them in the sense that you will feel you are not seeing what you need to be seeing unless you are wearing them when you work. (I keep a spare.)
(5) Some operators, particularly those with natural vision that requires considerable correction with glasses, will not be able to adapt to class IV high magnification, settling perhaps in the class III or low class IV range. A reputable company will allow you to make an exchange should you be unable to accommodate to a new set of loupes.
Caplan SA. Magnification in dentistry. J Esthet Dent. 1990;2(1):17-21.
Freedman G, Goldstep F. Magnification: getting bigger every day. Dent Today. 2003;2(8):108-113.
Morris GA, Kokott MI. A clear view no longer means a stiff neck. Dental Economics. July 1999.
Shanelec DA. Optical principals of dental loupes. CDA J. 1992;20(11):25-32.
Strassler HE, Syme SE, Serio F, et al. Enhanced visualization during dental practice using magnification systems [published correction
appears in Compend Contin Educ Dent. 1998;19(9):894]. Compend Contin Educ Dent. 1998;19(6):595-602.
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