Dentaltown November 2013 - (Page 85)

continuing education feature The dental profession has seen major advances in restorative care and CAD/CAM technology has been the catalyst that has propelled the profession into the 21st century. A few examples of things that are only possible with CAD/CAM include zirconium crowns, custom implant abutments, single-visit monolithic lithium disilicate restorations, precision implant bars, and combined cone beam and intra-oral scans for restorative-driven implant planning and surgical guide fabrication. Despite the advantages of CAD/CAM technology, many clinicians remain skeptical as to the quality of the restoration produced. One common misconception is that CAD/CAM restorations do not fit as well as conventionally fabricated restorations. First, the fit of conventionally fabricated restorations must be established and defined as it is presented in the literature. Many studies have been conducted evaluating marginal fit of non-CAD/CAM restorations, with marginal gaps ranging from 0 to 313μm with a mean marginal opening of 155μm.1-2 In an in vivo study, McLean and Fraunhofer examined more than 1,000 conventionally fabricated crowns after a five-year period. They found that a marginal opening of ≤120μm is clinically acceptable for conventionally cemented restorations. Interestingly, this average is much greater than the once suggested acceptable marginal gap of 25 to 40μm.3-4 Another study in agreement with McLean and Fraunhofer suggested acceptable clinical longevity with marginal gaps of 100-200μm.3-9 Likewise, a lot of research has been conducted evaluating the marginal fit of CAD/CAM-generated crowns. Even the last generation of CAD/CAM systems produced in-office milled restorations that fit just as well as laboratory-fabricated restorations. For example, one study of ceramic onlay restorations compared CEREC Bluecam restorations to laboratory-pressed restorations and found that the CEREC-produced restorations had better marginal fit.10 It has further been reported that the CEREC system yields reliable internal and marginal fit.11-14 In a study just published, Brawek et. al, compared the fit of restorations made from intra-oral scans with both the CEREC AC Bluecam and Lava COS and concluded that at the mean marginal gap of the Lava COS crowns were 51μm (±38μm) while the CEREC AC had a mean gap of 83μm (±51μm).15 Similarly, a study evaluated 37 restorations fabricated using the Lava COS and found excellent marginal fit, with a mean marginal gap of 48.65μm.16 Fourunit fixed partial dentures fabricated using the Lava COS were found to have better fit than restorations fabricated on the same cases using conventional impression techniques.17 In a separate study, clinicians evaluated over 117 cases where two restorations were made, one by CAD/CAM and another by a lab, and were asked to choose what one they thought was better. Blind to which crown was made using digital technology or conventional techniques, they chose the crown made digitally 68 percent of the time. Restorations fabricated with the previous generation E4D system have also been researched and found to have excellent fit. In a recent publication, e.max restorations fabricated using the E4D system on preparations of varying quality were evaluated. It was found that the mean marginal gap of crowns fabricated on ideal preparations was 38.5μm, those considered fair had a mean marginal gap of 58.3μm, while those categorized as poor averaged 90.1μm.18 1. Adair PJ, Grossmann DG: The castable ceramic crown. Int J Periodont Restor Dent 1984;4:33-45 11. Nakamura T, Dei N, Kojima T, Wakabayashi K. Marginal and internal fit of Cerec 3 CAD/CAM all-ceramic 2. Pera P, Gilodi S, Bassi F, et al: In vitro marginal adaptation of alumina porcelain ceramic crowns. J Prosthet Dent 12. Bindl A, Mormann WH. Marginal and internal fit of all-ceramic CAD/CAM crown-copings on chamfer prepara- 1994;72:585-590 3. Study Reference 1-2 1-2 3, 5-9 Study Reference 15 (Lava COS) 15 (CEREC AC) 18 (E4D - ideal prep) 18 (E4D - fair prep) 18 (E4D - poor prep) 5. tions. J Oral Rehabil 2005; 32: 441-447. 13. Quintas AF, Oliveira F, Bottino MA. Vertical marginal discrepancy of ceramic copings with different ceramic mate- 14. Kyu-Bok L, Charn-Woon P, Kyo-Han K and Tae-Yub K. Marginal and Internal Fit of All-ceramic Crowns 15. Brawek PK, Wolfart S, Endres L, Kirsten A, Reich S. The clinical accuracy of single crowns exclusively fabricated by 16. Scotti R, Cardelli P, Baldissara P, Monaco C. Clinical fitting of CAD/CAM zirconia single crowns generated from 17. Almeida E Silva JS, Erdelt K, Edelhoff D, Araújo E, Stimmelmayr M, Vieira LC, Güth JF. Marginal and internal rials, finish lines, and luting agents: an in vitro evaluation. J Prosthet Dent 2004; 92: 250-257. Karlsson S. The fit of Procera titanium crowns. An in vitro and clinical study. Acta Odontol Scand 1993;51:129-34. 7. Fabricated with Two Different CAD/CAM Systems. Dent Mater J 2008; 27: 422-6 Fransson B, Øilo G, Gjeitanger R. The fit of metal-ceramic crowns, a clinical study. Dent Mater 1985;1:197-9. 6. In-Sung Y, Jae-Ho Y, Jai-Bong L. In vitro marginal fit of three all-ceramic crown systems. J Prosthet Dent 2003; 90: 459-64 8. 9. digital workflow-the comparison of two systems. Clin Oral Investig. 2013 Jan 31. digital intraoral impressions based on active wavefront sampling. J Dent. 2011 Oct 17. [Epub ahead of print] Boening K, Reppel PD, Walter M. Non-cast titanium restorations in fixed prosthodontics. J Oral Rehabil 1992;19:281-7. fit of four-unit zirconia fixed dental prostheses based on digital and conventional impression techniques Clin Oral Björn AL, Björn H, Grcovic B. Marginal fit of restorations and its relation to periodontal bone level. II. Crowns. Investig. 2013 May 29 Odontol Revy 1970;21:337-46. 10. Keshvad A, Hooshmand T, Asefzadeh F, Khalilinejad F, Alihemmati M, Van Noort R. Marginal gap, internal fit, Mean Marginal Gap Produced (μm) 51 (± 38) 83 (± 51) 38.5 58.3 90.1 crowns. Int J Prosthodont 2003; 16: 244-248. American Dental Association, ANSI/ADA Specification No. 8 for zinc phosphate cement. In Guide to Dental Materials and Devices (ed 5). Chicago, IL: American Dental Association,1970-1971: 87-88. Recommended Mean Marginal Gap (μm) 155 ≤ 120 100-200 CAD/CAM-generated Restoration Studies McLean JW, von Fraunhofer JA: The estimation of cement film thickness by an in vivo technique. Br Dent J 1971;131:107-111 4. Restoration Longevity Studies 18. Renne W, McGill ST, Forshee KV, DeFee MR, Mennito AS. Predicting marginal fit of CAD/CAM crowns based on and fracture load of leucite-reinforced ceramic inlays fabricated by CEREC inLab and hot-pressed techniques. J the presence or absence of common preparation errors. J Prosthet Dent. 2012 Nov;108(5):310-5. doi: Prosthodont. 2011 Oct;20(7):535-40. doi: 10.1111/j.1532-849X.2011.00745.x. Epub 2011 Aug 1. 10.1016/S0022-3913(12)60183-8. continued on page 86 dentaltown.com « NOVEMBER 2013 85 http://www.dentaltown.com

Table of Contents for the Digital Edition of Dentaltown November 2013

Dentaltown.com Highlights
Howard Speaks: Not Getting it Done? Hire a Consultant
Professional Courtesy: Painful Advertising
Continuing Education Update
Second Opinion: The Role of Teamwork in the Third Era of Medicine
Deprogrammed Open Bite Can Help with Veneers
Bruxism Worse with Splint
Corporate Profile: Burbank Dental Laboratory
Product Profile: Eaglesoft 17
Debunking the Social Stigma of Stress
The Personal Side of Stress
In Your Face: Facing the Realities of Stress in Dentistry
When Tragedy Strikes: How to Prepare for and Recover from a Natural Disaster
The Latex Problem: It’s More Complicated Than You Think
Why Dentists Require Specific Exercise
How Much Money Can You Make When You’re Dead?
Denture Stabilizations with Small-diameter Implants
You Should Know: CrownMen
Product Profile: Synergy
Product Profile: NuSmiles ZR
Continuing Education: The New Evolution of Chariside CAD/CAM Technology
Ad Index
In This Issue: Dry Brush Inside Bottom Teeth First
Perio Reports
Dentally Incorrect
101 Ways to Reduce Stress
Achieving Goal Congruency

Dentaltown November 2013