Zirconia: Clinical Impressions an in Vivo Comparison of the Aesthetics of Various Zirconia Crowns

2 DENTAL MATERIALS

Zirconia: Clinical Impressions An In Vivo Comparison of the Aesthetics of Various Zirconia Crowns

INTRODUCTION There are many developments in dental materials with each passing year, but one of the most established solutions for a broken or structurally compromised tooth is a crown. Dental crowns have been constructed utiliz - ing composite, porcelain and gold (and semi- and nonprecious metals), several all-porce - Brent lain varieties, and recently zirconia. The shift Engelberg, DDS in dentistry to lifelike restorations that mimic natural tooth structure is undeniable, and zirconia crowns are considered “cosmet - Figure 1. Preoperative view of lower arch, including Figure 2. Working view of the lower arch teeth after ic” in nature compared to certain other alter - failing restorations on teeth Nos. 29 and 30. restoration removal. native crown materials. Based on perceived and actual patient demand owing to aesthetic and health concerns, material choices have dramatically shifted to “metal-free” wherever possible. This shift to “metal-free” is a bit iron - ic, since dental zirconia is technically an oxi - dized metal but is considered by dentists and patients to be metal-free. 1 Initially, zirconia crowns were predomi - nantly fabricated with a zirconia coping lay - ered or pressed with different types of porce - lain. Recently, a growing number of mono - lithic (full-contour) zirconia crowns have Figure 3. Close-up view of teeth Nos. 29 and 30, Figure 4. Lower arch view after initial cleanup. been requested by dentists, predominantly demonstrating decay and leaking restorations.

carpule of Septocaine (Septodont), and the Dental crowns have been constructed utilizing composite, porcelain and teeth were isolated (Isolite [Isolite Systems]). The old restorations were removed using a gold...several all-porcelain varieties, and recently zirconia. raptor 557 bur (Axis Dental) and a high- speed electric handpiece (KaVo Dental Handpieces) (Figures 2 and 3). The remain - as a result of ubiquitous laboratory market - caries were suspected. Finally, the patient ing cements, liners, and caries were ing. These full-contour zirconia crowns are desired restorations that were more aesthetic removed with a series of diamond burs, ie, extraordinarily strong, and it has been in this region of the mouth. KS0, KS1SC, KS3SC, and KS5SC (KOMET argued that they are just as aesthetic as lay - There are multiple aesthetic materials USA) and the rough crown margins were ered zirconia crowns. 2,3 In a routine restora - that would be indicated for this region, initially prepared (Figures 4 and 5). tive case, several varieties of zirconia including lithium disilicate, leucite-rein - After all visible caries were removed crowns were fabricated for comparison, and forced porcelain, and zirconia-based res - (Figure 6), the remaining dark areas were the results of this clinical case report follow. torations. A discussion with the patient in verified to be sound, and an anti-microbial this particular case confirmed that both scrub (Consepsis Pumice Scrub [Ultradent CASE REPORT teeth would be crowned with a zirconia- Products]) was applied to the preparations Diagnosis and Treatment Planning based restoration. Ease of cementation of and brushed across the teeth with a Star A 69-year-old male presented with failing the zirconia-based restoration with a resin- Brush (Ultradent Products) inside a slow- gold onlay restorations on teeth Nos. 29 and modified glass ionomer cement con - speed latch handpiece (KaVo Dental 30. After several decades of service, the patient tributed to the decision, as the mesial mar - Handpieces). A size 1 retraction cord was having occasional symptoms when gin of tooth No. 30 would clearly be subgin - (GingiBRAID [DUX Dental]) was carefully drinking cold beverages, and a contact had gival based on preoperative radiographs. 4 placed in the sulcus of both teeth to avoid opened between the 2 teeth (Figure 1). In addi - fluid contamination during the crown tion, the margins were slightly open in sever - Clinical Treatment buildups and to minimize bleeding poten - al areas around both gold restorations, and The patient was anesthetized with one continued on page xx

DENTISTRYTODAY.COM • JULY 2012 4 DENTAL MATERIALS

Zirconia: Clinical Impressions... ing a zirconia coping (LPZ) (Figure 11) continued from page 00 ...the lack of in vivo studies makes it difficult to draw any effective 4. Multilayered porcelain (5 lay - ers) over a zirconia coping (MLPZ) tial in any subgingival preparation conclusions regarding full-contour zirconia-based crowns, render - (Figure 12). areas. ing the growing use of these crowns for our patients premature. It was requested that the 4 crown Once cleaned and ready for the types were to be made as identical as crown buildups, the teeth were etched possible in shape and contour for with 37% phosphoric acid (Ultra-Etch limited concern for unintentional tion’s margin was slightly subgingival comparison purposes at the delivery [Ultradent Products]) for 20 seconds contamination of the sulcular area (Figures 7 and 8). appointment. per tooth and thoroughly rinsed. A that could have arisen from “blowing” Final impressions were made uti - desensitizer (Telio Desensitizer [Ivo - the monomer with an air syringe to lizing vinyl polysiloxane impression Observations at Placement clar Vivadent]) was placed for 20 sec - remove the solvent. 6 The teeth were material (Imprint 3 Garant [3M As this was an experiment for the pur - onds per tooth, and the excess liquid each light-cured for 20 seconds with ESPE]). Then, the provisional restora - pose of comparing the aesthetics of was evaporated with a high-speed an LED light (Bluephase [Ivoclar tions were formed (Protemp [3M different zirconia crown types, each evaporation tip. A fifth-generation Vivadent]), and the build-up material ESPE]) and seated with provisional crown was photographed in the adhesive (One-Step [BISCO Dental was applied (Luxacore [Zenith Dental]) cement (Fynal [DENTSPLY Caulk]). patient’s mouth. The crowns will be Products]) was applied for a period of and light-cured for 20 seconds per The patient was given postoperative discussed in 2 categories: full-contour more than 20 seconds per tooth, and tooth. and hygiene instructions for care of and layered. the excess solvent was removed again, Next, the preparations were com - the provisionals during the following In the case of the full-contour with the aid of high-speed evapora - pleted, and the final margin positions 3 weeks. Instructions were sent to the restorations, the FCZP pair appeared to tion. This evaporation technique effec - were established and smoothed with dental laboratory team requesting the have a high luster, and the physical zir - tively removes the undesirable solvent the KS3SC, KS5SC, KS6SC, and fabricating of 4 different types of zir - conia material simply looked different (acetone), without blowing uncured 8856.021 burs (KOMET USA). Careful conia crowns: in every way than a natural tooth liquid resin monomer across the adja - consideration was made to ensure 1. Full-contour zirconia: polished (Figures 13 and 14). Zirconia is opaque cent teeth and into the sulcus, poten - accurate and smooth margins with only (FCZP) (Figure 9) by nature, 7,8 and the more translucent tially causing bleeding. 5 Another ben - minimal disruption to the surround - 2. Full-contour zirconia: stained a restoration is (given a healthy prepa - efit is a cleaner margin when the ing tissue; even on the mesial of tooth and glazed (FCZSG) (Figure 10) ration stump shade), the more natural preparation is completed, as there is No. 30 where the previous restora - 3. Layered porcelain (2 layers) dur - continued on page xx

Figure 5. Close-up view of teeth Nos. 29 and Figure 6. Lower arch view of the completed Figure 7. Close-up view of teeth Nos. 29 and Figure 8. Lateral view of the completed 30, after caries removal and initial margin preparations. 30, after crown buildups and preparation preparations. placement. completion.

Figure 9. Laboratory lateral view of the full- Figure 10. Laboratory lateral view of the full- Figure 11. Laboratory lateral view of the lay - Figure 12. Clinical occlusal view of the full- contour zirconia polished restorations. contour zirconia stained and glazed restora - ered zirconia restorations. contour zirconia stained and glazed restora - tions. tions.

Figure 13. Clinical lateral view of the full-con - Figure 14. Clinical occlusal view of the full- Figure 15. Clinical lateral view of the full-con - Figure 16. Clinical occlusal view of the full-con - tour zirconia polished restorations. contour zirconia polished restorations. tour zirconia stained and glazed restorations. tour zirconia stained and glazed restorations.

DENTISTRYTODAY.COM • JULY 2012 5 DENTAL MATERIALS

Figure 17. Clinical lateral view of the layered Figure 18. Clinical occlusal view of the lay - Figure 19. Clinical lateral view of the multiple Figure 20. Clinical occlusal view of the multi - zirconia restorations. ered zirconia restorations. layered zirconia restorations. ple layered zirconia restorations.

Zirconia: Clinical Impressions... cement into place after discussion wear to the opposing dentition, and Relative translucency of six all-ceramic systems. Part 1: core materials. J Prosthet Dent . continued from page 00 with the patient. would be the most difficult and poten - 2002;88:4-9. tially damaging to remove in the future. 9. Luo XP, Zhang L. Effect of veneering techniques 9,10 on color and translucency of Y-TZP. J Prosthodont . the restoration will appear. As there DISCUSSION It appears that the increasing trend 2010;19:465-470. is no ability to “block out” the opaque The layering technique requires more toward full-contour zirconia-based 10. McLaren EA, Giordano RA II. Zirconia-based ceramics: material properties, esthetics, and lay - zirconia coping with layering, the pol - time and, therefore, typically higher crowns should be met with caution, ering techniques of a new veneering porcelain, ished-only crowns’ opacity stood out dental laboratory fees for the final and not only due to aesthetic limita - VM9. Quintessence Dent Technol . 2005;28:99- 111. significantly among the surrounding restoration. In general, the strength of tions. Practices placing these full-con - 11. Barão VA, Gennari-Filho H, Goiato MC, et al. natural dentition. layered porcelain to substrates (cop - tour restorations must be equipped Factors to achieve aesthetics in all-ceramic 2 restorations. J Craniofac Surg . 2010;21:2007- The FCZSG pair clearly appeared ings) is in the 120 MPa range; this with staining, glazing, and polishing 2012. more aesthetic than the FCZP crowns applies to PFM crowns as well as lay - equipment for use before seating these 12. Yener ES, Ozcan M, Kazazolu E. The effect of glazing on the biaxial flexural strength of different (Figures 15 and 16). From the author’s ered zirconia restorations. This means crowns. Other factors need to be con - zirconia core materials. Acta Odontol Latinoam . experience, in restorative situations a decrease in strength from more than sidered, including occlusal adjust - 2011;24:133-140. 13. Edelhoff D, Brix O. All-ceramic restorations in dif - where there is a dark preparation 1,000 MPa (the full-contour zirconia ments that would require the place - ferent indications: a case series. J Am Dent stump, zirconia restorations are often restoration), but clearly a more aes - ment of the opposing tooth against a Assoc . 2011;142(suppl 2):14S-19S. 12 14. Guazzato M, Proos K, Sara G, et al. Strength, reli - considered or selected as the coping thetic restoration for the patient. It “nonpolished” zirconia crown that ability, and mode of fracture of bilayered porce - material. This selection is based on zir - has been proven that the coping will potentially wear faster. lain/core ceramics. Int J Prosthodont . 2004;17:142-149. conia’s ability to block the dark under - design for layered zirconia crowns has 15. Martínez-Rus F, Suárez MJ, Rivera B, et al. lying stump from show-through in the largest impact on resistance to CONCLUSION Evaluation of the absolute marginal discrepancy 7,11 of zirconia-based ceramic copings. J Prosthet the restoration. However, if the chipping of layered porcelain off of Today, dentists and patients demand Dent . 2011;105:108-114. entire crown is comprised of this opa - these restorations. 10,17-19 If the dental predictable materials, treatments, and 16. Guess PC, Schultheis S, Bonfante EA, et al. All- ceramic systems: laboratory and clinical per - cious material, the limited light trans - laboratory team is able to meet the results. However, the lack of in vivo formance. Dent Clin North Am . 2011;55:333- mission through this thickness of known ideals in coping design, a studies makes it difficult to draw any 352, ix. 17. Larsson C. Zirconium dioxide based dental restorative material appears to have a strength of layered porcelain in the effective conclusions regarding full- restorations. Studies on clinical performance and substantial aesthetic downside. In 120 MPa range should be successful, contour zirconia-based crowns, ren - fracture behaviour. Swed Dent J Suppl . 2011;(213):9-84. fact, while the FCZSG crowns offered as it has been utilized for decades with dering the growing use of these 18. McLaren EA, White SN. Survival of In-Ceram slight aesthetic improvement, it is PFM restorations. crowns for our patients premature. ! crowns in a private practice: a prospective clini - cal trial. J Prosthet Dent . 2000;83:216-222. very difficult to consistently stain and A potential drawback of full-con - 19. McLaren EA, Whiteman YY. Ceramics: rationale glaze an all-zirconia crown. 12 tour zirconia based restorations could Acknowledgement for material selection. Compend Contin Educ Dent . 2010;31:666-672. It was subjectively determined be wear compatibility to the opposing The author extends a special thanks to 20. Ghuman T, Beck P, Ramp LC, et al. Wear of enam - that the 2 varieties of layered crown enamel, reminiscent of Vita Alpha Todd Franson of First Impressions el antagonist to ceramic surfaces. J Dent Res . 2010;89(special issue B). Abstract 1394. pairs were aesthetically superior. Not porcelain, during routine function. Dental Lab in Schaumburg, Ill, for his 21. Jung YS, Lee JW, Choi YJ, et al. A study on the in- only did the layered restorations more Wear to teeth opposing zirconia has outstanding laboratory work, and for vitro wear of the natural tooth structure by oppos - ing zirconia or dental porcelain. J Adv closely mimic the natural shade and not been studied with signifi - his willingness to make the extra Prosthodont . 2010;2:111-115. translucency characteristics of the cance. 20,21 Furthermore, in a clench - restorations required for the purpose of surrounding natural dentition; they ing or bruxing patient, what is the material and technique comparisons. Dr. Engelberg earned his BS degree in psy - looked far more realistic to the impact of full-contour zirconia on the chology at Indiana University in 1999 and his DDS from the Indiana University School of patient himself. When layering the opposing dentition long-term? References Dentistry in 2003. His private practice, porcelain, a zirconia coping is Unfortunately, no dental restora - 1. Giordano R, McLaren EA. Ceramics duringview: classification by microstructure and processing Arlington Heights Smiles, focuses on primarily designed to fit to the restoration mar - tion can be expected to last forever. methods. Compend Contin Educ Dent . adult cosmetic and restorative dentistry. Dr. gin, much like a metal coping would Therefore, inevitably many of these 2010;31:682-688. Engelberg lectures on aesthetic dentistry and 2. Guazzato M, Proos K, Quach L, et al. Strength, has published articles on cosmetic dentistry, be designed prior to layering porce - crowns will need to be replaced. reliability and mode of fracture of bilayered porce - full-mouth rehabilitation, and porcelain lain over a PFM crown. 13,14 Although When the time comes, can a full-con - lain/zirconia (Y-TZP) dental ceramics. veneers. Dr. Engelberg is also a co-director of Biomaterials . 2004;25:5045-5052. “Total Advantage Live,” a hands-on course the zirconia coping is opaque, the tour zirconia crown be easily re - 3. Vichi A, Louca C, Corciolani G, et al. Color related teaching cosmetic dentistry and veneers with porcelain layered over it can be much moved? Will the heat and vibration to ceramic and zirconia restorations: a review. Dent Mater. 2011;27:97-108. ceramist Brad Jones to other dentists. Please more translucent. The combination of generated in the removal of a full-con - 4. Komine F, Blatz MB, Matsumura H. Current sta - visit ahsmiles.com or totaladvantagelive.com coping and layered porcelain can pro - tour zirconia crown likely damage tus of zirconia-based fixed restorations. J Oral for specific information on cosmetic cases, Sci . 2010;52:531-539. dental treatment, or upcoming course details. duce very aesthetic results while still instruments and, more importantly, 5. van Dijken JW, Sjöström S. Development of gin - He can be reached at (847) 259-6988 or achieving an extremely accurate mar - the patient’s underlying tooth? givitis around aged restorations of resin-modified [email protected]. glass ionomer cement, polyacid-modified resin ginal fit of the crown without adding If the pros and cons of layered ver - composite (compomer) and resin composite. Clin Disclosure: Dr. Engelberg reports no disclosures. substantial fabrication time. 15,16 sus full-contour zirconia crowns are Oral Investig . 1998;2:180-183. 6. Magne P, Nielsen B. Interactions between impres - There was a slight increase in aes - compared, the less aesthetic full-con - sion materials and immediate dentin sealing. J thetics with the MLPZ pair versus the tour zirconia restorations, as subjective - Prosthet Dent . 2009;102:298-305. 7. Raptis NV, Michalakis KX, Hirayama H. Optical LPZ pair (Figures 17 to 20), and this ly determined in this case study, also behavior of current ceramic systems. Int J was selected as the crown pair to have the least long-term research on Periodontics Restorative Dent . 2006;26:31-41. 8. Heffernan MJ, Aquilino SA, Diaz-Arnold AM, et al.

DENTISTRYTODAY.COM • JULY 2012