Diastema closure, Filling gaps between teeth, Reverse smile line
This Highland Park, IL patient was concerned that she showed too much gum on the sides of her smile and her front teeth were too short and too small for her face. When the front teeth are shorter than the side teeth, it is called a "reverse smile line". She was tired of having her old dentist replace the bonding that filled the gaps between her teeth every 5 years and wanted her teeth to look better. She was a nighttime tooth clencher-grinder and the composite bonding chipped frequently. Her dentist was worried that if he placed veneers, they would break off due to the bruxism.
Making the "smile line" follow the contour of the lower lip, natural optical qualities of feldspathic porcelain
The patient had bilateral "gum lifts", also called crown lengthening, to reduce the amount of tissue showing in her smile from side views and 6 "feldspathic porcelain veneers". Feldspathic veneers have optical characteristics that most closely match natural teeth. The veneers were used to fill the gaps between the teeth and to give her a more appealing smile line. Porcelain veneers are an ideal restorative option to fill gaps or spaces between the teeth. Many dentists will drill too much tooth structure away when they prepare teeth for veneers. When your dentist is conservative with the tooth preparation and leaves the majority of enamel in place, the veneer bond is extremely high and the tooth is actually strengthened by the new veneer. This makes these restorations perfect for night grinders.
Feldspathic veneers are made with a hand stacking technique where small amounts of porcelain of different opacities, levels of brightness, and color are artfully laid down and a tooth form is built up. Less drilling is needed usually because feldspathic veneers match existing tooth shades better than pressed coping veneers do. Due to the unmatched blending capabilities of these restorations, this is the ceramic choice that is the least likely to ever have a black line at the gumline. The custom craftsmanship process of building feldspathic restorations yields a vibrant and vital appearance to the veneers that can create the most natural and life-like smile makeovers that can be achieved.
Feldspathic veneers have been losing market share in the United States. It is not because this hand crafted type of veneer is of less quality or that it does not last as long. In the rapidly evolving world of cosmetic dentistry, the market for feldspathic veneers would disappear instantly if that were true. This type of veneer takes longer to make and requires more training on both the lab and dentist sides. They are usually more costly to produce and are more technique sensitive for the dentist to deliver. Creating and providing feldspathic veneers is an art that is mainly left for the high end market.
Are feldspathic veneers strong?
It depends on your dentist and how much tooth is left. When your dentist is conservative with tooth preparation and leaves the majority of enamel in place, the feldspathic veneer bond is extremely high and the tooth is actually strengthened by the presence of the new veneer. The feldspathic restoration is considered monolithic with one type of porcelain. It does not have a strong coping substructure to support it. The tensile strength of 85 MPa is low on its own and needs to be treated like fine china until it is bonded onto the tooth. This type of restoration gains its strength from the bond to enamel. If supported and bonded to enamel, it is incredibly strong and suitable choices for night grinders. Many, if not the majority of dentists will drill too much tooth structure away when they prepare teeth for veneers. If much of the enamel is lost during preparation, and less than 50% of the remaining exposed clinical crown has enamel to bond to, then the feldspathic porcelain restoration will be one of the weakest restorative options and is contraindicated for patients who are tough on their teeth. Understandably, the choice of restorative material is often made intra-operatively.
Monolithic versus Bi-layered porcelains
A feldspathic veneer is considered monolithic or one layered. Studies on ceramic failures show that when porcelain crowns and veneers chip or break, it usually occurs as an “adhesive failure”, meaning that a fracture occurs between the different porcelain layers as opposed to a “cohesive failure” which is fracture within one of the layers. Monolithic restorations tend to be stronger than bi-layered porcelain (coping with veneering layer on top) because it does not have an interface of two bodies of ceramic with differing tensile strengths and coefficients of expansion. Te strongest monolithic porcelain available in the existing dental market is E Max monolithic.
If any type of cosmetic dentistry is requested, the more qualified cosmetic dentist or prosthodontist will do a dento-facial analysis. This analysis is an assessment of how the face and lip symmetry affect how the teeth display in a smile. The lips are said to be the picture frame for the teeth. It is customary for the dentist to take a series of photographs documenting the smile at many angles as well as how the gum tissue is shaped. Measurements are then taken on major landmarks on these images and compared with prevailing norms. If any ratios vary “significantly” from the norm, then the patient is offered the customary and usual treatment protocol to fix the problem. It is the patient’s right, privilege, and responsibility to make the final decisions on what treatment offerings are done based on the individual’s vision of importance.
“Reverse Smile Line”
One of the norms described in the previous paragraph is to evaluate the shape the lower lip takes with a big smile. Generally it will take the shape of a shallow “U”. When the smile is viewed from slightly above the teeth, the upper front teeth edges should also align in the form of a “U” which parallels the low lip. The patient above did have a normal lip shape pre-operatively but the upper incisal edges aligned in a reverse way, called a reverse smile line.