Bonding by Dr Chan Joon Yee When a painted wall in your home becomes indelibly stained, what do you do? Yes, you'd paint it. If you decide to make the wall less stainable and easier to clean, you could also bond ceramic tiles to it. In dentistry, bonding is the method by which a dentist adds a tooth coloured material to the surfaces of your teeth to mask underlying discolouration, cavities, gaps or undesirable contours or alignment. Like the wall in your home, there are 2 methods of bonding, namely direct and indirect bonding. Direct Bonding We have upgraded to a new cordless LED curing light (left). The light is cool, it's more powerful in terms of pure light intensity and does the job in half the time that older machines take. The older halogen light unit (right) is cumbersome and heat-generating. The tooth or teeth to be treated are first trimmed to reduce or roughen the surfaces that are to be bonded. Next, chemicals are applied to the surfaces of the teeth to improve the grip in much the same way you would apply paint primers. Then, a composite material of the desired colour is applied to the surface of the tooth and allowed to harden. The results are faster and more dramatic than bleaching. You can theoretically "paint" your teeth as white as you want. For shape or alignment correction, the dentist will add material to the tooth to thicken it in some areas. By selectively thickening certain parts of a tooth that are slightly out of place, the treated tooth can be made to flush with the other teeth. In a similar way, teeth can be slightly enlarged by adding material to close gaps between them. Putting on braces may be the ideal treatment for crooked teeth, but bonding yields immediate results and costs much less. One limitation to bonding is that you can only add but not subtract. To correct the positions of teeth that are too bulging, you'll have see an orthodontist. Another setback is the strength and durability of composites. These materials seldom last more than 5 years. You are likely to need repairs and patch up every few years. Cost Estimation Tooth coloured fillings/bonding S$100-S$200 Indirect Bonding (laminates/veneers) Also known as veneering, the most frequently used materials in indirect bonding are ceramics. Bonding ceramic veneers to teeth is like bonding tiles to a wall. A veneer is often simply a thin shell of tooth-coloured ceramic that slips over just the outer surface of the tooth. The surface of the teeth to be veneered are first thinned down to make space for the veneers. The amount of trimming required is very minimal, usually only 0.5mm. After preparation, an accurate impression is taken of the teeth and the rest of your mouth. From this impression, a cast is made. If necessary, temporary veneers are cemented to cover the trimmed surfaces of your teeth. Inside the laboratory, ceramic veneers (porcelain, Empress, Cercon etc) are fabricated to fit your prepared teeth exactly. With the advent of newer and stronger ceramics, we do not recommend porcelain veneers anymore. Besides being stronger, the newer generation of ceramics are also more translucent and cosmetic. When the dentist gets the finished veneers, he will call you back and then bond them to your teeth. Veneers are quite similar to crowns, except that unlike crowns which wrap around all surfaces of the tooth, veneers only cover a couple of visible surfaces. Veneers are also often much thinner than crowns. Like opaque composites, ceramic veneers cemented with the appropriate cement can mask underlying discolouration and correct minor crookedness. Indirect bonding is preferable to composites because the materials used are more durable. They are expected to last twice as long as composites and even though they are not tough enough for you to chew crab shells and sugar cane, ceramic veneers are considerably stronger than composites. However, due to the complexity of the procedures, ceramic veneers cost a lot more than bonding. In fact, they cost as much as crowns. The main reason for this is that veneers are very thin and translucent. The final cementation stage is a delicate step in which different pastes must be tried on to determine the final appearance before the right cement can be selected. After cementation, some adjustment to the edges of the veneers is often necessary. All this extra work adds to the cost of veneers, making them as expensive as crowns. Veneers are a good idea for young people who don't want too much of their natural teeth to be trimmed. That's about it. There is a price to be paid of trimming too little of the natural teeth. The difficulties to the dentist are numerous. If the aim of veneering is to mask deep discolouration, then the preparation of the teeth to be masked will be a tricky procedure. All contact areas and margins are at risk of having the dark underlying colour showing through. Hence, the same procedure may yield different results in different people depending on the initial condition their teeth are in. The durability of veneers depend on several factors. One key factor is the bond strength between the tooth and the veneer. If the veneer is bonded to enamel, then the bond strength can be very high. If the tooth is so worn out that all enamel is lost after trimming, then bond strength will be weaker. The way the patient's jaws come together can also affect the durability of veneers. People with deep and heavy bites will tend to dislodge their own veneers. Hence, people who do veneers should be mentally prepared to have their veneers replaced in 5 to 10 years. For people who want to do up their once and for all and expect "expensive" things to last "forever", then crowns may be more suitable for them. Cost Estimation Empress veneers S$800 each Please call 62358316 for appointments or email us