Resurfacing Tooth Structure With Ceramic Laminates

INTRODUCTION
Through adhesive dentistry, we can resurface natural tooth structure to improve aesthetics, function, and dental health. Composite resin can be directly placed in many clinical situations, but this treatment modality requires that the provider be both the clinician and the artist. My experience tells me that composite resin can be expected to last up to 10-plus years when placed with excellence and in correctly indicated clinical situations.

Relaminating tooth structure with ceramic materials can result in a more durable and stain-resistant surface. In my practice, patients are informed that they can expect about twice the life from these restorations as compared to direct composite alternatives. In-office CAD/CAM technology can allow these laminates to be produced in a single appointment, but the majority of dentists that I know still utilize a commercial dental laboratory, delivering these restorations in 2 appointments. With the indirect process, a team approach is utilized; the clinician and the artistic ceramist combine their talents to create optimal restorative outcomes.

In this article, several clinical cases will be shared that demonstrate how natural teeth can be resurfaced with ceramic laminates. First, I would like to address some brief background information on the materials being used in these cases.

Bonding Agents
I currently use 5th and 7th generation bonding agents for these all-ceramic restorations. The 5th generation bonding agents utilize the total-etch process, and the primer and bonding agent are applied simultaneously. The one-step 7th generation bonding agents contain the etchant, primer, and the bonding agent. Several manufacturers have developed “universal” bonding agents that can be used with, or without, total-etch.

Luting Composites
There are many excellent luting composites on the market. I have considerable experience with the 3 of them used here, but there are a number of others from which to choose. Light-cured and dual-cured alternatives are available. There are also a few that are considered self-adhesive, requiring no bonding agent or silane primer.

Ceramics
Stacked (also referred to as layered) feldspathic porcelain can be used to produce thin veneers for teeth that need littl or no tooth preparation. The powder/liquid process of hand mixing by the ceramist allows for the layering of color throughout the ceramic material, producing excellent aesthetics with no external staining. The bonding process helps increase the strength to a level that is clinically acceptable in various situations. Where heavy function is not a factor, this material can be a good aesthetic choice for laminates.

Pressed or milled ceramics with increased leucite content can be used to nearly double the strength of layered (nonreinforced) feldspathic porcelain. However, the color is monochromatic unless the surface is cut back and lower strength ceramics are used to layer the surface.

Lithium dislicate is a unique ceramic that is nearly twice the strength of luecite-reinforced pressed or milled ceramics. It can be pressed or milled and is also monochromatic until layered with a (weaker) surface porcelain. However, the layering porcelains can be applied in very thin layers, increasing aesthetics without significantly decreasing the underlying strength of the restorations.

For my patients who desire or need tooth resurfacing, I prescribe feldspathic laminates when occlusion is not a major factor in the long-term outlook for the case, and lithium dislicate laminates when heavier occlusal function is or may be a contributing factor.

CASE REPORTS
Case 1
Figure 1 shows a patient who wanted an update for her direct veneers that she said had been in place for nearly 10 years. Her previous dentist had placed them in order to close diastemas on the mesial and distal of both maxillary central incisors.

Upon removal of the composite resin with a carbide finishing bur (ET 9 [Brasseler USA]), it was obvious that there had been very little previously completed tooth preparation, and total enamel bonding would be possible. It was decided that we would include the lateral incisors for better proportions.

Fine diamond burs (8850 KR 014 [Brasseler USA]) were used to contour the 4 anterior teeth for draw. Figure 2 shows the minimally prepared teeth, as readied for the enamel bonding procedures. Final impressions were taken with a vinyl polysiloxane (VPS) impression material (Aquasil Ultra [DENTSPLY Caulk]). In this case, no provisional restorations were necessary.

Figure 1. Old composite resin veneers on teeth Nos. 8 and 9.	Figure 2. Composite removed and teeth Nos. 7 to 10 prepared for thin laminate veneers.
Figure 3. Thin feldspathic veneers (Optec [Jeneric Pentron]) ready for placement.	Figure 4. Etching of prepared enamel surfaces.
Figure 5. The 5th generation bonding agent (Prime & Bond NT [DENTSPLY Caulk]) applied to etched surfaces.	Figure 6. Thin laminates placed with light-cured luting composite (Calibra [DENTSPLY Caulk]).

Figure 7. Final result.

Thin laminate veneers were fabricated by our ceramist, using feldspathic porcelain (Optec [Jeneric Pentron]) in an enamel shade (Figure 3). The intaglio surfaces of the restorations were hydrofluoric (HF) acid-etched and then returned to our office to be bonded into place using a total-etch technique.

In Figure 4, the 4 teeth are shown being etched with 34% phosphoric acid gel for 10 seconds. The etching gel was then thoroughly rinsed with an air/water syringe, an oil-free air stream applied, leaving them left slightly moist. A 5th generation bonding agent (Prime & Bond NT [DENTSPLY Caulk] was liberally applied using a brush (Figure 5) and lightly dried with oil-free air from the air/water syringe. The bonding agent was light cured for 10 seconds with an LED curing light (Bluephase [Ivoclar Vivadent]). Silane (Calibra Silane Coupling Agent [DENTSPLY Caulk]) was applied to the intaglio HF acid-etched surfaces of the veneers and dried. A light-cured composite resin cement (Calibra [DENTSPLY Caulk]) was then applied to the etched and silanated surfaces, and the veneers were gently seated on the prepared teeth (Figure 6). Next, the LED curing light was used to “tack” the veneers (one to 2 seconds per tooth) at the margins. Then, excess luting composite was removed using a No. 12 Bard Parker surgical blade, and floss was taken through the proximal areas before the curing light was used for 20 seconds on each veneer. Any remaining composite resin cement was removed using small carbide finishing burs (ET kit [Brasseler USA]). Final polishing was accomplished using finishing and polishing cups (Enhance [DENTSPLY Caulk]). The final result can be seen in Figure 7.

Case 2
Figure 8 shows a close-up view of anterior maxillary teeth with less than acceptable morphology, resulting in abnormal spacing and contours. The patient was in excellent dental health but had excess tissue at the facial margins of teeth Nos. 6 to 11. She desired laminates to achieve better form/surfaces that would be more proportional and lighter in color.

After tissue laser contouring with a diode laser (AMD Picasso [DENTSPLY International]) and minor tooth preparation using fine diamond burs, impressions were taken (Panasil [Kettenbach LP]) and sent to the laboratory team. Provisional restorations were fabricated using a bis-acryl provisional material (Luxatemp [DMG America]).

At the seating appointment, the provisional veneers were removed and tissue cord (Ultrapack No. 2 [Ultadent Products]) was placed. The prepared teeth (with cord in place) are shown in Figure 9, as readied for veneer placement. Thin feldspathic veneers (Durathin Veneers [Experience Lab]) were fabricated by the ceramist. Then, they were HF acid-etched in the lab and returned to our office. Figure 10 shows one of the veneers ready for placement.

Figure 8. Poor morphology in these anterior teeth with diastemas and slight tissue overgrowth.	Figure 9. Prepared teeth with cord (Ultrapack Mo. 2 [Ultradent Products]) in place ready for veneer placement.
Figure 10. Durathin Veneers (Experience Laboratory) feldspathic laminate ready for placement.	Figure 11. Etching gel (UNI-ETCH [BISCO Dental Products]) placed on prepared surfaces.
Figure 12. Universal bonding agent applied to etched tooth surfaces (ALL-BOND UNIVERSAL [BISCO Dental Products]).	Figure 13. Durathin Veneers restorations were placed with light-cured luting composite (CHOICE 2 [BISCO Dental Products]).

Figure 14. Final result.

The internally etched porcelain surfaces were treated with silane (Silane Primer [BISCO Dental Products]) and air-dried. Porcelain Bonding Resin (BISCO Dental Products) was applied to the inner surface of the veneers and air-thinned. Then, the prepared surfaces of the teeth were etched (Figure 11) with 34% phosphoric acid (UNI-ETCH [BISCO Dental Products]) for 10 seconds and then the teeth were thoroughly rinsed with water from an air/water syringe. Next, a universal bonding agent (ALL-BOND UNIVERSAL [BISCO Dental Products]) was liberally applied (Figure 12) and blown thin using oil-free air. The bonding agent was light cured for 10 seconds with our LED curing light. A light-cured composite resin cement (CHOICE 2 [BISCO Dental Products]) was applied to the inner surfaces of the veneers. (The Milky Bright shade was chosen to raise the value a bit.) Next, the restorations were placed on the prepared teeth (Figure 13). All 6 veneers were placed and “tacked” into place using the LED curing light (one to 2 seconds each). The excess cured composite was removed with a No. 12 surgical blade. Any excess interproximal composite resin was removed with floss before the luting agent was completely cured, using an LED curing light for 20 seconds each. Marginal finishing was completed using small finishing carbide burs (ET kit). Polishing was completed with Enhance polishing cups and points. Figure 14 shows the final result.

Case 3
A young lady wanted an improved smile for her upcoming wedding. The facial surfaces of her teeth are shown in Figure 15. The lingual surfaces of her maxillary anterior teeth had been affected by acid erosion (Figure 16). The first premolar teeth showed pitting on the incisal edges of the facial cusp tips.

It was decided to prepare for 360° laminates to resurface all the coronal surfaces of the 6 anterior teeth and veneers, including the incisal aspects of the facial cusp tips of the first premolars. Lithium disilicate (IPS e.max [Ivoclar Vivadent]) was chosen as the restorative material for its strength and excellent aesthetics.

Preparation with fine diamond burs (Brasseler USA) involved minimal tooth removal for the facial surfaces, creating smooth chamfer margins at the height of the tissue, and leaving in place a high percentage of enamel (Figure 17). The lingual reduction resulted in enough space for our lab team to create 0.5-mm thick lithium disilicate restorations. The finished preparations can be seen in Figure 18. Final impressions were taken with a VPS impression material (Panasil), and then provisional restorations were fabricated using a bis-acryl provisional material (Luxatemp).

Figure 15. Facial view of the acid-damaged anterior teeth.	Figure 16. Incisal view, showing acid erosion.
Figure 17. Prepared teeth Nos. 5 to 12, facial view.	Figure 18. Prepared teeth, incisal view.
Figure 19. Lithium disilicate (IPS e.max [Ivoclar Vivadent]) laminates (created by the Experience Lab team) are ready for placement.	Figure 20. Etching of the prepared tooth surfaces.
Figure 21. Etching gel rinsed. Then, the teeth were dried with oil-free air, but not desiccated.	Figure 22. Laminates placed with self-adhesive luting composite (Opal White FUSION-ZR [Taub Dental]), being delivered and held in place with a “Veneer Stick” (Taub Dental).
Figure 23. Final result, facial view.	Figure 24. Final result, incisal view.

Figure 19 shows the six 360° laminates and 2 veneers that were fabricated at the dental laboratory (Experience Lab). At the placement appointment, the provisionals were removed and the restorations were tried-in and approved by the patient. She desired a slight increase in value. A self-adhesive composite resin cement (Opal White FUSION-ZR [Taub Dental]) was chosen for this case. The manufacturer’s instructions indicate that the luting composite can be used with or without a bonding agent. In addition, this luting composite does not require that a silane-coupling agent be applied on the internal ceramic surfaces. Figure 20 shows the central incisors being etched with 34% phosphoric acid gel for 10 seconds. The etched teeth were thoroughly rinsed using water from an air/water syringe and lightly air-dried but not desiccated (Figure 21). The Opal White FUSION-ZR was applied to the internal (previously HF acid-etched) surfaces of the laminates. Then, the restorations were placed on the prepared teeth and fully seated using a “Veneer Stick” (Taub Dental) (Figure 22). The dual-cure version of the luting agent was chosen for its autocuring ability. At the gel stage, the excess composite at the margins was removed with a No. 12 surgical blade and floss was used to remove excess material in the interproximal areas. An LED curing light was then used for 10 seconds on the facial and lingual surfaces of the restorations.

The occlusion was checked using articulating paper (Bausch BK01 200 µm), and adjustments were made to the ceramic surfaces using fine finishing diamonds, 30-fluted finishing burs and porcelain polishing points (W16 DG, W16DM, W16D, in order [Brasseler USA]). The final results are shown in Figures 23 and 24.

IN SUMMARY
The series of case reports presented in this article have demonstrated clinical techniques involved in the resurfacing of natural tooth structure using ceramic laminates to solve various aesthetic and/or functional problems. Current bonding agents and luting composites suitable for such restorations, and with which I have had considerable clinical experience, were also briefly discussed. There are a variety of very good materials on the market from which to choose.
In my practice experience, ceramic laminates can be expected to last about twice as long as direct composite alternatives, making them an excellent patient treatment choice, when indicated.

Dr. Nash operates a general dental practice in Huntersville, NC, where he focuses on aesthetic dental treatment. A Fellow in the American Academy of Cosmetic Dentistry and a Diplomate for the American Board of Dental Aesthetics, he is co-founder of the Nash Institute for Dental Learning, also in Huntersville, where he offers courses in aesthetic and cosmetic dentistry. He presents internationally on subjects in this area. He has authored 2 chapters in dental textbooks and has published numerous articles in dental publications. He was a chemical engineer before entering dental school and is a consultant to numerous dental product manufacturers. He can be reached via his mobile phone at (704) 904-3458, via e-mail at rosswnashdds@aol.com, or by visiting the Web site located at thenashinstitute.com.

Disclosure: Dr. Nash reports no disclosures.