Last year, I was invited by professor (and my personal friend) Fernanda Faot to plan a non prep veneer restoration case. I felt butterflies in my stomach, typical of one that knows the weight of the responsibility! It was my first veneer patient! But since I love challenges, I accepted it right away! The result was very exciting and we celebrated in great style: the presentation of a beautiful lecture by my dear student Mariana Piassa!
As I believe that knowledge should be shared, I present you a part of Mari’s work. The objective was to clarify the main clinical questions about this technique, and therefore, the discussion was written as questions and answers.
I hope this publication helps to clarify some of your questions! I wish you all an excellent reading! =)
1. What are non prep veneer restorations?
According to the literature, non prep veneer restorations are ultra-thin restorations with a thickness less than 0.5 mm thick, usually made ??of ceramic (Kina & Bruguera, 2007; De Andrade et al, 2012; Gresnigt & Ozcan, 2011). They are indicated in very limited cases, basically when you want to change the shape of the teeth by adding restorative material. In other words, when the tooth receives virtually no preparation with drills (Kina & Bruguera, 2007). The success of these restorations is directly associated with adhesive cementation, which is held, in these cases, on enamel (De Andrade et al , 2012).
2. When do I use non prep veneers or conventional veneers?
Conventional veneers are indicated to correct teeth with color alterations, changes in form and malformations. All these indications suggest that the teeth are subjected to a dental preparation for making the restorations (Kina & Bruguera, 2007). The non prep veneer restorations have more limited applications: just to correct the form of teeth that need little or no preparation! As the thickness of the restoration is very thin (less than 0.5 mm), the end result is a highly translucent restoration and for this reason can not be indicated for correction of teeth with any color change (Kina & Bruguera, 2007).
3. Can it be said that the difference between the non prep veneers and the conventional veneers is whether or not to prepare the teeth?
Based on the literature, it can be stated that the need of tooth preparation is one of the differences between the two types of restorations. And this is subject of a lot of discussions. However, it is noteworthy that the performance of small wear strain accumulation some areas, as well as the making of a limit or cervical end are needed in cases of " contact lenses ". That means, whenever there is need to prepare a greater or lesser amount. Furthermore, there is a difference in thickness of the workpiece between the two ceramic restorations : the contact lens is less than 0.5mm thick, while the conventional laminates have an average thickness of between 0.5mm and 1.0mm.
4. How to start the treatment planning?
Just like any other treatment, planning is based on a thorough clinical and radiographic examination. It is essential that the patient is healthy. After all, nothing is more important than the health and the function! The facial and dental esthetics analysis should also precede the restorative treatment. The details of the vertical dimension of occlusion, dental arches, occlusal plane, sagittal midline, smile line, gingival contour, proportion of teeth, among others should be evaluated too (Fradeani, 2006; Magne & Belser, 2002). Facial and intraoral photos and articulated casts are indispensable! (De Andrade et al, 2012; Fradeani, 2006; Ittipuriphat & Leevailoj, 2013; Magne & Belser, 2002).
5. What is the "Wax -up”?
It is the diagnostic waxing! It aims to define the form and the final position of the teeth from the waxing of the casts. It is essential the accurate knowledge of the dental arches and the occlusal plane, knowledge of anatomy, proportion and dental harmony. Based on the diagnostic wax-up one can manufacture a silicon guide that will direct where the preparation must be done and the tooth must be worn. This step, along with the " mock-up”, defines the restorative strategy (De Andrade et al, 2012; Magne & Belser, 2002).
6. What is the "Mock -up" and how can it be implemented and tested clinically?
The "mock-up" is the intraoral restorative test, carried out from the diagnostic waxing. The "mock-up" is intended to endorse restorative treatment plan set in wax (De Andrade et al, 2012; Magne & Belser, 2002; Magne & Belser, 2004). The simplest “mock-up" is to make a temporary restoration with bis-acrylic resin, a self-curing material that does not release heat during polymerization (Magne & Belser, 2002). The first step is to prepare a tray guide from the wax model. The bis- acrylic resin is placed on the tray guide and the whole is taken into intraoral position. After polymerization of the resin, the tray is removed and the "mock-up" ready (Magne & Belser, 2002). At this time, the patient and the professional can assess all the details of how will the final restoration be. It is possible that the patient stays with the restorative trial in mouth for a few days to evaluate the expectation of the final restorations (Magne & Belser, 2002).
7. Is it necessary to perform a temporary restoration after preparation for non prep veneers?
There is no need to do it. After all, little preparation is performed. There is no dentin exposure and little change will be noted in the natural shape of the teeth of the patient. However, if the patient wishes, as in cases of diastema closure or conoids teeth, a provisional can be made using bis-acrylic resin, based on the diagnostic wax (like the mock-up) or even a freehand direct composite restoration.
8. How to know the tooth preparation limits?
The best way to make the preparation is by means of a guide. Just as one prepares a tray guide, with impression material, it is possible to perform a preparation guide based on the impression of the diagnostic wax-up. This guide should be cut in strategic positions, so that the clinician can observe where the tooth must be prepared and where the enamel can be preserved9.
9. Which are the relevant informations that we need to tell the dental technician?
The success of the treatment is directly related to the excellent communication between the dentist and the dental technician (Magne & Belser, 2004). Thus, it is essential that the technician receives all necessary information for making the prosthetic pieces, from the previous information, casts, diagnostic wax-up and photographs. The dentist can also make use of manual drawings to inform details about the optical properties and the texture of the teeth (De Andrade et al, 2012; Magne & Belser, 2004).
10. What cementing agent should be used?
The cement should always be adhesive! However, we should pay some attention to the contraindications: ( 1 ) resin cements chemically activated and " dual " cements - the tertiary amine presented in these materials turns the cement into yellow over time and therefore the restoration undergoes color changes; ( 2 ) self-adhesive resin cements - they are opaque cements that affect the final esthetic results of the restorations. Thus, the cementation can only be performed with resin cement or light cured “flow" composites. These cements do not turn yellow over time. In addition, the thickness of the contact lens does not interfere with the passage of light curing unit set, so these materials adequately polymerize in this clinical situation ( Kina & Bruguera, 2007; Turgut & Bagis, 2013). Some light curing cements have proof of folders ("try- in"), that can be used to test the interference of the cement's color in the final result. After using it and selecting of cement color, "try -in" paste can be removed from the ceramic piece with alcohol or water ( Kina & Bruguera, 2007).
11. How is the cementing technique?
Both the ceramic piece and the tooth structure must be properly treated.
1. Treatment of ceramic laminate or non prep veneers: the inner surface is the part to be conditioned with hydrofluoric acid, the concentration of the acid and the time are determined in accordance to the kind of ceramic that is being treated. After conditioning, silanization is carried out. A thin layer of pure adhesive is applied to the workpiece surface before applying the resin cement.
2. Treatment of dental structure: the enamel is conditioned with 35 % or 37% phosphoric acid for 30 seconds, followed by thorough washing, drying and adhesive application. It is recommended not polymerize the adhesive prior to cementation to avoid mismatch. The resin cement is applied on the piece and is brought into the tooth. The excess should be removed before polymerization. It is recommended that the dentist cements each veneer at a time, especially for beginners. (De Andrade et al, 2012; Kina & Bruguera, 2007). After polymerization of all restorations, it is recommended to remove the excess with scalpel blades and to polish the interface with adequate burs.
12. What is the longevity of these restorations ?
Opposite from what you could be thinking, non prep veneers restorations are being made for a long time, but were not known by this nomenclature. Eighteen years ago, Materndomini & Fridman published a paper in the Journal of Esthetic and Restorative Dentistry, where they discuss the application of ultra thin ceramic restorations. However, there is record in the literature that properly assesses the longevity of this kind of restorations. What we expect is that longitudinal clinical trial results are soon presented and, based on that, we can finally have good information to discuss the pros and cons of this kind of restorations.
What I am able to report on the longevity of this case is that after one year, the functional and esthetic results remain! The veneers are perfectly suited, no marginal staining was observed, occlusion and disocclusion are appropriate and the patient is very happy!!! And I could verify this last week! Sabrina returned to the clinic last week, October 14! And it was super gratifying to see the her happiness and the treatment's success! I know that one year of monitoring is very little time... but this is just the beginning of a long history!! My goal is to monitor Sabrina for a long time!!! There are some photos of our last week meeting below!
I hope that this post has cleared up some questions! Do not forget to leave your comments and your suggestions! The best learning happens in the discussion forums! Join and share your ideas!!
My purpose is to help you gain autonomy through knowledge, facilitating the dentistry and communication. AND how do I do this?
I put myself in your shoed, I identify what is preventing you from being happy with your results and untie the knots by means of a simple and accessible language! I graduated from UNESP | Araçatuba; did my Master and PhD in Operative Dentistry at UNESP Araraquara | I am a Professor of Operative Dentistry at the Federal University of Pelotas | RS.
Jul, 27th 2015