I’ve always believed that majority of dentists do seriously practice our oath, “First Do No Harm”. However, we are only human and do make mistakes. In fact, our mistakes makes us better dentists. As one speaker said ”That’s why it is called dental practice as we often times practice dentistry to our patients.” When I heard it, I both got amused and sad because it’s actually true. Thus, why I and the rest of our team at DMD Center do this blog and vlog. DMD Center wants for us to continually be reminded of what we already know in dental practice but sometimes forget and provide information that we should know, but, probably don’t know. On this post, I will share the most common causes of why we tend to fail sometimes when it comes to doing veneer treatment and really simple measurements to take on how to avoid them.
Over and Under Tooth Reduction
As the saying goes, “too much or too little is not good”, same goes to dentistry especially on veneer preparation. An over or under reduced tooth preparation doesn’t bid well for the success of your veneer treatment. Depending on the kind of veneer and what you are trying to achieve on this treatment lies on how much tooth reduction is needed in your tooth preparation. There’s an ideal measurement on how much a dentist should do veneer preparation as we discussed on the Part 1 of this blog: https://dmd.center/blog/types-of-veneers-and-how-to-prepare-them/. However, knowing the ideal tooth reduction measurement is totally different from implementing it especially since we are in fact just most of the time estimating the tooth reduction we do as we are doing it. So, here are some tips to avoid this mistake:
- Use a depth guide bur - this can truly provide you an accurate measurement in your tooth reduction.
- Use the hand piece as both the measuring and cutting instrument. This is done by concentrating on the top surface of the head of hand piece, which is perpendicular to the shank of the bur and by using burs of known dimensions.
- Proper tooth reduction requires the complete control of all rotary instruments. A good grasp should be maintained on the handpiece while the hand rests firmly on other teeth in the arch.
Debonding of the Veneer Restoration
One of the things we truly want to avoid is for our final restoration to unsuspectingly gets totally separated from our patient’s tooth after our treatment. This often results to a lot of our nightmares not only probable lost of profit for us but total lost of our patient’s confidence with us. As majority of our restorations nowadays have something to do with bonding our restorations to the teeth, it is critical that we do this procedure right. Here are some of the tips to avoid this issue:
- Choose well the bonding agent you are going to use. Don’t use the bonding agent just because it is included in the composite kit we purchased. The bonding agent we should use is at least in 5th generation, it has alcohol as its solvent and must at least have a bonding strength of 17 MPa or even better as high as it can get because bonding strength goes down after 24 hours.
- As much as possible end your tooth preparation on enamel. This has always been the principle of tooth preparation especially in consideration to bonding. Dentin is hydrophilic, composites are hydrophobic and bonding works well with enamel rather than on dentin surface. Thus, on these conditions, your best bet is for your final restorative material, more so, if composite to bond on the enamel rather than on dentin.
- Air thin dry the bonding agent at least 10-30 seconds to allow the bonding agent to penetrate the dentinal tubules that was etched.
- Do not apply the bonding agent too thick and agitate it well during the application. Placing the bonding too thick just results a space in between the tooth and your composite resin cement. The bonding agent won't be able to fully penetrate into the dentinal tubules especially if it is not air properly into a thin layer and given enough time.
- The clinical application of 2% chlorhexidine (for dental use NOT mouthwash) for one minute to the etched dentin after rinsing off the acid and before applying the dentin bonding primer and resin is able to stop significant in vivo degradation of bond strength from MMPs (Matrix Metalloproteinases). Phosphoric acid in the acid etch and rinse bonding process and acid primers in the self etch process are implicated in the release of these proteases and their activation by several non-collagen proteins also released from dentin by the etching. MMPs are released in saliva by salivary glands, by cells in the gingival crevices to crevicular fluid and by pulpal odontoblasts cells to the dentinal fluids. Studies shows MMPs results to bond strength deterioration over time and the ability of Chlorhexidine to prevent bond deterioration by inhibiting MMP action.
Leakage on the Final Cementation
In every lecture I do, I always mention the fact to the participants that dentistry is a matter of practice of conscience. This is because when we make mistakes even unknowingly like this error. Majority of the time, the consequence/s of what we did only shows after a certain period of time. Thus, we don’t get blamed from it and more often than not, even earn from our own mistakes. Leakage of our restorations like in veneer treatment can result to recurrent caries which takes time to happen, so, if this occurs, we even earn from this error such as the patient may end up needing a crown or bridge or even ending to RCT or extraction, and, the most famous and favourite treatment of choice recently by dentists, implant. And, this is where our conscience comes in. So, how do we avoid it?
- Proper isolation of the tooth during cementation. The use of rubber dam is still the best barrier from contamination and moisture. If rubber dam is not an option or we don’t want as an option, then, at least use a properly rolled cotton (not done manually), dri-aid barrier, tongue retractor and angle widener.
- Investing in a good LED light that fully cures no matter what the photoinitiator is added by the manufacturer of the composites we use in our clinic. If the cost of your mobile phone is higher than the cost of your LED light, then, you are better off using your old halogen light cure unit to cure your composites. Check the wavelength of your LED lights and if you are unsure of it, cure the composite cement longer as it is prescribed.
- Use a composite sealer with low viscosity allows excellent penetration to unseen leakage we might have created during finishing and polishing. Apply this on the cavosurface margins at the junction of your restoration and the tooth.