April 1, 2014
by Ron Goodlin, DDS, AAACD, FIADE, FAGD
The internet provides a vast amount of information for our patients. Dental websites and articles, showcasing the best work under ideal circumstances, have resulted in increased patient demands and expectations. Today’s practitioners must be able to provide high quality cosmetic dentistry in an efficient and predictable manner.
The theory behind this technique is very simple. Replace enamel with enamel and dentin with dentin.1
Although it is easier to use a single coloured composite, the addition of a few extra steps to layer your restoration replacing dentin with dentin-like materials and enamel with enamel-like materials will provide an aesthetic result that will meet even the highest of patient expectations.
The “inside out” method suggests the practitioner start by creating a dentin sub-layer followed by enamel layer. The “Lingual to Labial” method, is a much more predictable approach for most practitioners as it begins with the creation of a thin lingual enamel wall. This technique vastly improves the predictability and the efficiency, making it a less time consuming procedure (Fig. 1).
FIGURE 1. Review of maxillary central anatomy.
The building of the lingual shelf first provides the ideal incisal edge position (IEP)2 and provides a platform on which to support the creation of the dentinal lobes and subsequent placement of the appropriate translucency between those lobes.
Materials Selection. There are a myriad of direct composite materials available, and most have a variety of colours as well as translucency/opacity options to choose from. Dentin-like materials generally have a higher filler particle size making them stronger, less shrinkage and have a firmer handling characteristic. These dentin materials also mimic the opacity and colour of dentin, yellow A2 or A3 (vita shade guide) with about 10 percent opacity.3
Enamel-like materials have less opacity, between 30 and 60 percent and are generally made of finer filler particles to give a high long lasting polish, great wear characteristics but with less strength and higher shrinkage.4
Empress Direct by Ivoclar Vivadent (Amherst N.Y.), Point 4 by Kerr (Washington DC) Filtek Supreme by 3M Espe and many others have specific dentin and enamel materials as well as translucent materials in complete composite restorative systems that allow the practitioner to easily mimic the normal dental (dentin and enamel) anatomy.5,6
STEP 1: TOOTH PREPARATION
The first step is to start with a clean tooth. The enamel must be devoid of plaque, stain, or pellicle layer. By using a non-fluoridated pumice and water buccal and lingual prophylaxis is completed using a prophy cup and/or brush.7
Interproximal cleaning using floss is not enough to guarantee a great bond, it is recommended to use an interproximal strip (be careful to not elicit any bleeding) for this purpose.
Shade selection and translucency determination should occur immediately after cleaning the tooth. It is important to choose the shade before you begin the procedure as the tooth will dry out and make the tooth appear lighter than it actually is. Using a vita shade guide, choose the shade and then find an enamel shade that will complement. Place a small ball of material on the surface and light cure to ensure the composite material shade is correct. Now determine the dentin shade the same way. Finally, look carefully at the adjacent teeth to determine the amount of translucency. Then, use a black block out paddle to the lingual to help confirm the degree of translucency required. Categorize the translucency as none, moderate or pronounced.
Now study the tooth contours, labial anatomy and texture, making a mental note, or make notations on the before photograph, or a quick drawing, so that you know what is to be duplicated later8 (Figs. 2a & b). Many practitioners choose to refer to the before photographs during the fabrication of the tooth contours.
FIGURE 2A. AND 2B. Images of a class IV fracture on a central incisor.
The next step is to create a long bevel from the fractured area up onto the intact enamel surface. There are three reasons to create a long bevel. First, it has been shown that a long bevel will expose enamel rods for improved bonding. Secondly, be generous with this knife edged bevel, as it will assist the practitioner in developing an even colour transition zone, eliminating a line of demarcation between the filling and the tooth. Finally, the bevel will assist the practitioner in utilizing a greater percentage of enamel to bond thus strengthening the restoration.9 In cases where there is more dentin than enamel to bond to, a full coverage restoration is recommended10 (Figs. 3a & 3b).
FIGURE 3A. AND 3B. Images of extension of long bevel with knife edge finish line.
Whenever the practitioner is removing decay, or placing a bevel, tissue management is a key component of success. It is critical to ensure high bond strength by ensuring that the tooth surface is not contaminated by bleeding or sero-sanguinous sulcular fluid. If so packing cord is recommended. The packing cord should remain in place during the procedure and removed just prior to final polishing. Careful attention to being very gentle around the tissue will go a long way to ensure a successful bonded restoration. The proper application of rubber dam is a great way to protect the gingival tissue from extraneous saliva and sulcular fluid leakage.
Following tooth preparation, use a total acid etch technique by applying 37 percent phosphoric acid (H3PO4) for 30 seconds to one minute to create a frostlike surface on the enamel. If after etching, rinsing and drying there is still not an adequate frosted surface repeat the etch procedure
Once the tooth is dried and frosted, the application of an enamel-bonding agent will create the strongest and longest lasting bond. It is a common procedure to apply a dentin bonding agent to the exposed dentin (Adhese by Ivoclar) and a separate enamel bonding agent to the enamel (Scotchbond) to achieve the maximum bond strength.
STEP 2: LINGUAL ENAMEL SHELF
The re-creation of the lingual enamel shelf serves two important purposes. First it will replace the missing tooth structure with an enamel-like material, (Enamel 30 percent translucency) and secondly it provides a stable platform on which to create the dentin lobes during the following step.
There are two ways to support the lingual shelf of enamel when placing the uncured composite material. The first option is to create a polyvinyl siloxane index and utilize that as a stable platform to create a thin lingual enamel wall. This technique is typically utilized when restoring multiple teeth. A diagnostic wax up is most often created first in the lab and stent is made from that. Using a putty PVS material an incisal index is created. With this technique a small ball of material is placed in the index and pressed into place, then using an ipc instrument thin and shape the material using the index to support the material, thus creating the lingual enamel shelf.
Alternately, and usually for one or two teeth, the practitioner may choose to use the ball of the index finger to support the formation of the lingual shelf while creating the desired shape and thickness. After curing, the finger support is removed and the incisal edge position and lingual anatomy is refined using a combination of diamond burs and rotary discs (Figs. 4a & 4b).
FIGURE 4A. AND 4B. Images of translucent enamel lingual shelf using finger support.
STEP 3: DENTIN
Re-creating the dentin lobes and material is the next step. Choose a colour, usually A2 or A3; rarely it will be darker A3.5 or A4, or lighter A1 or B1. Place a ball of material so that it covers the lingual shelf, extending over the first 2 mm of the bevelled edge, and make sure it is 1/2 mm short of the IEP (Incisal edge position). Putty it into place, but do not cure.
The next step is to create lobes using an IPC or a cone shaped instrument. Simply cut into the incisal dentin material to create a pattern of slices thus creating an irregularly shaped pattern to simulate dentinal lobes. Gently form the lobe to make a gradual incline from the incisal to the bulk that is just slightly covering the initial part of the enamel bevel using a pointed brush. Light cure (Figs. 5a & 5b).
STEP 4: TRANSLUCENCY
Creating the degree of translucency to match the adjacent teeth is very important to make sure the characterization created will be aesthetic. The degree of translucency required is determined by looking at the adjacent teeth and rating the translucency as none, medium or pronounced. For cases with no translucency, you can skip to the next step, placing the labial enamel. For medium translucency cases use 30 percent translucent enamel material, while for a pronounced translucency effect, use a 50 percent translucent material such as a trans Opal.
The translucent material is placed using an IPC (thin bladed interproximal carving) instrument. Putty the translucent material in the depressions created between the lobes stopping just short of the incisal edge. The material should be flush with the dentin material, just filling in the lobes. Light cure (Figs. 6a & 6b).
FIGURE 6A. AND 6B. Images of translucency characterization puttied between dentinal lobes.
STEP 5: LABIAL ENAMEL SHADE
Finally we are ready to recreate the labial enamel anatomy utilizing the enamel composite material of the original shade taken just after the tooth was prophied. Remember the material may look just slightly too dark at this stage, because the tooth itself may have slightly dehydrated and may appear lighter accordingly. Now place the enamel shade composite from beyond the IEP all the way up to beyond the bevel that is towards the apical portion of the tooth. It is common practice to use the ball of your index finger to initially place the labial material. Fine tuning of the initial shape is done using a flat bladed composite instrument. Now recreate the labial anatomy and surface texture using a cone shaped instrument, the edge of the IPC and then smooth using a flat shaped brush dipped in modelling resin to create a smooth transition. It is very important to recreate the labial anatomy so that the light reflects off the surface of the tooth in a similar manner to the adjacent natural tooth. Sight incisally to duplicate the labial contours, shape the labial, lingual, and incisal embrasure spaces and light cure (Figs. 7a & 7b).
STEP 6: ADJUST AND POLISH
The shape of the tooth must match the adjacent teeth in order for the restoration to look natural. Take extra time to duplicate incisal and labial embrasure forms, incisal edge position and labial contours. Initial shaping can be achieved using a Soflex disc followed by a long needle shaped multi fluted carbide bur. Polish using your favourite composite polishing system (Figs. 8a & b).
FIGURE 8A. AND 8B. Images of shape adjustment and polishing.
Re-creation of the natural anatomy with a layering technique11 whereby the practitioner replaces missing dentin with dentin like composite and enamel with enamel like composite, a highly esthetic restoration can be achieved with efficiency and predictability.OH
Dr. Goodlin is an accredited member of the American Academy of Cosmetic Dentistry, and is the Immediate Past President of the American Academy of Cosmetic Dentistry (2012-13). Dr Goodlin served as the president of the Toronto Academy of Cosmetic Dentistry (2008-2010), was a co-founder of the Canadian Academy of Cosmetic Dentistry and served as the editor of the Canadian Journal of Cosmetic Dentistry for 6 years. Dr. Goodlin is a Fellow of the International Academy of Dento Facial Aesthetics as well as a fellow of the Academy of General Dentistry. He holds his dental licenses in Ontario, Florida and Texas. Dr. Goodlin created and taught the Cosmetic Dentistry Elective Program at the University of Toronto Faculty of Dentistry and maintains a full time practice limited to “Cosmetic Dentistry” in Toronto Canada.
Dr. Goodlin’s Dental accomplishment are just as numerous, with many prestigious awards, AACD Accreditation, the AGD clinician scholarship, and two Alpha Omega Meritorious service awards, ODA recognition, as well as a very successful Dental practice to his credit. He is the past President of the Aurora Dental Study club, and served on several committees at the Canadian Academy of Cosmetic Dentistry, the Ontario Dental Association and the Canadian, Toronto, and American Academies of Cosmetic Dentistry.
Dr. Goodlin has many Cosmetic Dentistry and Dental Photography articles, research papers and editorials to his credit, which have been printed in the AACD journal, the journal of the Canadian Dental Association the Journal of the Toronto Academy of Cosmetic Dentistry and Oral Health Magazine and Dental Clinics of North America.
For more information please go to his website at www.smiledental.ca
Dr. Goodlin Graduated from the University of Toronto in 1980, and has dedicated his career to the advancement of Cosmetic Dentistry. He is a popular and well sought after speaker, appearing regularly across Canada, the US and Europe.
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