One of the most common esthetic situations that I see in my practice day-to-day are people who have excessive gingival tissue over their maxillary anterior teeth. They present with maxillary anteriors that seem out of proportion, small and square. Sometimes this is a part of what they would like to alter and it comes up in my pre-clinical interview, and other times it is something I make note of as I am doing my exam. The patient I am talking about, is most often female, I have not gone to the literature to see if this has been proven scientifically, but it is the trend in my world. When I do the dentition exam they have very little to no wear on their maxillary anteriors, so they haven’t worn the teeth down into a short, square shape.
Last week I had an 18 year old female patient come in on an emergency visit. She was clear that she had a toothache on the lower left side, pulling back her cheek and pointing to her lower second molar. The discomfort had started several days ago, and been getting progressively worse. It seemed to be at it’s worse int he middle of the night when it woke her up from sleep. It was a dull pain, no throbbing, and could be controlled with OTC pain medication, but then came right back. Her medical history was non-contributory and her dental history included ortho 5 years prior, for which she was still wearing her retainers at night, cleanings and one or two fillings.
Last week on Facebook int he chat window across came the question, how do you manage dark dentin when placing composites. This is not the first time I have been asked this question, nor the first time I have asked myself the same thing. One of the key factors in getting an exquisite esthetic result with tooth colored restorative materials is the underlying prep color. Sclerotic dentin and amalgam staining from old restorations are an everyday hurdle to overcome. The question is how to manage these clinically. The majority of our tooth colored restorative materials are translucent, so discolored dentin will show through and create shadowing or alter the overall value and appearance of the finished product. The translucency of composite is very close to that of enamel, so if I can build up my preparation in a way that I have recreated the natural dentin contours, leaving only the enamel layer to replace and accomplish the chroma, hue and opacity of dentin, the rest is simple.
Placing an exquisite composite restoration on an anterior tooth involves managing lots of moving parts. My focus is creating an incredible final result where the color is such that the restoration disappears into the tooth, and the interproximal contour is so smooth that even a hygienist with loupes and floss can’t find anything to criticize. The challenge that I run into is a matrix system that actually meets my needs. I have tried many of the different mylar strip systems, and there have been many advances in this arena, resulting in great choices.
For a matrix band to work effectively, and not result in the operator having a lot of contouring and correction to handle with a bur it needs to meet a few criteria, I became acquainted again with these criteria when preparing for a program and going back to a well-known text on operative dentistry.
Seating small all porcelain restorations, inlays and onlays, can be very challenging. I find they are difficult to hold and maneuver in and out of the mouth, even if I use the placement tools. In my hands this challenge gets larger exponentially during the cementation process due to the presence of the resin cement. Now the restoration are not just small and delicate, they are slippery.
I have been known, more than once I have to admit, of loosing my grip on an inlay or onlay and having to retrieve it from the floor, or worse the patient’s mouth!! These embarrassing educational moments have influenced my technique. One of the worst consequences would be for the patient to swallow the restoration before we have a chance to seat it.
I had a patient come in today with a onlay out on the upper left first bicuspid. Fortunately the onlay and the tooth were in perfect shape and we would be able to bond it back in place. The challenge of doing this was returning both the tooth and the inside of the porcelain onlay to fresh surfaces that would accept a bond. In this case all the resin cement was on the intaglio surface of the onlay, and getting the tooth ready would not be the issue. The idea of picking up a handpiece to clean the inside of an all porcelain onlay however, is gut wrenching. Using a hand instrument to clean it out is an exercise in frustration.
Years ago while doing some research for a program on posterior composites I came across interesting information about how interproximal wedges work. The article looked at the distance the teeth were separated over the time the wedge was in place. What caught my eye was that the effect of the wedge increased for the first few minutes it was in place. I immediately incorporated the concept of pre-wedging while doing posterior composites. As soon as the anesthesia has taken effect I place the largest wedge I can in the interproximal between any teeth where I will be preparing the interproxmal.
Since than with the routine use of sectional matrix systems and the effectiveness of the ring separators the concept of pre-wedging has fallen out of favor and when I discuss it in a lecture I get asked why I still follow this protocol. This week I decided to answer that question for myself and on Tuesday treated two patients, both scheduled for posterior composites, without pre-wedging. Wednesday morning I came in to the office more committed then ever to always placing the wedge as the first step in class two and three restorations.
A routine procedure in my office is the restoration of a single posterior tooth with a crown or onlay The tooth is being restored for structural or biologic reasons, and we are accepting the existing occlusion with only minor alterations to the existing tooth form. At the completion of the preparation we need to fabricate a provisional that will seal the prep and hold tooth position occlusally as well as interproximally.
One of the most efficient and effective ways to create a matrix for the provisional is with a triple tray and bite registration silicone. Silicone bite registration material is highly accurate and captures all of the existing tooth anatomy and occlusal form. It is also extremely rigid and undergoes very little distortion so the provisional requires only minor adjustments with a bur. The two complications that can occur with this technique are that the patient does not bite down during the impression into MIP, and that the teeth may be to wet.
Until today I hadn’t given any thought to the lifespan, care and maintenance of the separation rings that I use in the office to create tight interproximal contacts when placing a posterior composite restoration. The quality of the contact, however, is something I think about each and every day. Creating a contact that is tight enough and has the appropriate shape to prevent food impaction following restoration is a critical factor in success of the procedure. This last week I struggled through a patient appointment where we completed three class 3 restorations, the frustration came from trying to manage the matrix system and create those ideal contacts. This morning I went in search of an explanation for why I had so much trouble with the separation rings, for a system I have used and really loved for years.
Getting back an exquisitely matched restoration is one of the challenges of daily practice. At the heart of this frustration is gathering and sending the ceramist the information and records to help them do their best work. At the center of this information is shade selection. When I think about selecting a shade, I know that I am actually selecting three separate factors, Value, Chroma and Hue. Of the three, my experience is that matching the value is the critical piece, and the one least often communicated to the lab.
Value is an assessment of the reflectiveness of a tooth or restoration. We assess it as being light to dark, or white to black on a scale. There are many factors that influence the value of a restoration, and our goal is to give as much of that information to the lab, so they can create the result we are looking for. This is a combination of gathering the records and maximizing our ability to interpret it.