Selected Research on CEREC ^® 

Hickel R, Manhart J., Longevity of restorations in posterior teeth and reasons for failure. J of Adhesive Dent 3(1):45-64, 2001 Spring

PURPOSE: This article compiles a survey on the longevity of restorations in stress-bearing posterior cavities and assesses possible reasons for failure.

MATERIALS AND METHODS: The dental literature predominantly of the last decade was reviewed for longitudinal, controlled clinical studies and retrospective cross-sectional studies of posterior restorations. Only studies investigating the clinical performance of restorations in permanent teeth were included. Longevity and annual failure rates of amalgam, direct composite restorations, glass ionomers and derivative products, composite and ceramic inlays, and cast gold restorations were determined for Class I and II cavities.

RESULTS: Annual failure rates in posterior stress-bearing restorations are:

0% to 7% for amalgam restorations,
0% to 9% for direct composites,
1.4% to 14.4% for glass ionomers and derivatives,
0% to 11.8% for composite inlays,
0% to 7.5% for ceramic restorations,
0% to 4.4% for CAD/CAM (CEREC) ceramic restorations, and
0% to 5.9% for cast gold inlays and onlays.

CONCLUSION: Longevity of dental restorations is dependent upon many different factors that are related to materials, the patient, and the dentist. The principal reasons for failure were secondary caries, fracture, marginal deficiencies, wear, and postoperative sensitivity. A distinction must be made between factors causing early failures and those that are responsible for restoration loss after several years of service.

A website of dentists who assist others using CEREC, called PlanetCEREC, compiles Research on CEREC

 www.planetcerec.com/research/

“Browse through the most complete collection of CEREC-related research on the internet. We've categorized the data into three parts:”

n Margins & Fit

n Longevity, Wear & Bonding

• n Charts -- Two of the relevant charts on
• • Sensitivity after placing various materials and
  • a Comparison of the Thermal Expansion of different dental restorative materials
     are copied from that site below:

This chart comes from Clinical Research Associates, November 1999. The CEREC® ceramic is highlighted in red:

Information compiled by PlanetCerec, March 2001

Interpretation:

The higher the value associated with a product, the more it expands when temperatures rise in the oral cavity. Therefor, of the materials studied, we see "Composite resin" has the most expansion when exposed to increased temperatures. Notice VITA Mark II is in between the expansions of Tooth root and crown.

Nakamura T, Dei N, Kojima T, Wakabayashi K. Marginal and internal fit of CEREC 3 CAD/CAM all-ceramic crowns. Eur J Oral Sci. 2003; 111(2): 163 – 169.

PURPOSE: The purpose of this study was to examine the effects of the occlusal convergence angle of the abutment and the computer's luting space setting on the marginal and internal fit of CEREC 3 computer-aided design/manufacturing (CAD/CAM) all-ceramic crowns.

MATERIALS AND METHODS: Mandibular second premolar all ceramic crowns were fabricated for nine different conditions using CEREC 3: all combinations of abutments with three different total occlusal convergence angles (4, 8, and 12 degrees) with three different luting space settings (10, 30, and 50 micron). The completed crowns were seated on the abutments, and the marginal gaps were measured. The internal gaps between the crowns and abutments were also measured, using test-fit silicone paste.

RESULTS: When the luting space was set to 10 micron, the marginal gaps of the crowns were greater than when it was set to 30 or 50 micron. When the luting space was set to 30 or 50 micron, the marginal gaps ranged from 53 to 67 micron and were not affected by the occlusal convergence angle of the abutment. The internal gaps were within a range of 116 to 162 micron and tended to decrease as the occlusal convergence angle of the abutment decreased.

CONCLUSION: When the luting space was set to 30 microns, crowns with a good fit could be fabricated on the CEREC 3 system, regardless of the occlusal convergence angle of the abutment. [Dr R’s Note: CEREC 3-D is even more accurate and we have used the 30 micron setting from the start of our usage of CEREC]
 

If you would like to search the National Library of Medicine for research studies on CEREC® Click Here and enter CEREC® or any other search terms you want information on.

Some studies that I think are most relevant are:

Sjogren G, Molin M, van Dijken JW. Department of Odontology, Faculty of Medicine and Odontology, Umea University, Sweden. Goran.Sjogren@odont.umu.se
A 10-year prospective evaluation of CAD/CAM-manufactured (CEREC) ceramic inlays cemented with a chemically cured or dual-cured resin composite. Int J Prosthodont. 2004 Mar -Apr;17(2):241-6.

PURPOSE: The present follow-up study was carried out to evaluate the performance of Class II CEREC® inlays after 10 years of clinical service.

MATERIALS AND METHODS: Sixty-six Class II CAD/CAM ceramic inlays were placed in 27 patients. Each patient received at least one inlay luted with a dual-cured resin composite and one inlay luted with a chemically cured resin composite. At the 10-year recall, 25 (93%) patients with 61 (92%) inlays were available for evaluation using a slight modification of the USPHS criteria.

RESULTS: Fifty-four (89%) of the 61 inlays reevaluated still functioned well at the 10-year recall. During the follow -up period, seven (11%) of the inlays required replacement because of: four inlay fractures, one cusp fracture, endodontic problems in one case, and postoperative symptoms in one case. All the replaced inlays had been luted with the dual-cured resin composite. The fractured inlays were all placed in molars. The estimated survival rate after 10 years was 89%, 77% for the dual-cured resin composite-luted inlays and 100% for the chemically cured resin composite-luted ones. The difference was statistically significant.

CONCLUSION: Patient satisfaction with and acceptance of the CEREC®
inlays were high, and the performance after 10 years of clinical service was acceptable, especially regarding the inlays luted with the chemically cured resin composite. The properties of the luting agents seem to affect the longevity of the type of ceramic inlays evaluated.

[Dr. Rosenberg’s Note: Both cements and the 3D software have improved by “generations” since this ten study was begun and today’s CEREC® 3D restorations should be even more accurate and last longer.]
 

Posselt A, Kerschbaum T. Klinik fur Zahn-, Mund- und Kieferheilkunde, Universitat zu Koln Abtlg. fur Vorklinische Zahnheilkunde, Koln-Lindenthal, Germany. aposselt@gmx.de
Longevity of 2328 chairside CEREC® inlays and onlays. Int J Comput Dent. 2003 Jul;
6(3):231-48.

In a dental practice, 2328 ceramic inlays were placed in 794 patients. The restorations were manufactured chairside using CEREC® technology and adhesively inserted at the same appointment. The clinical performance of the restorations was evaluated with the Kaplan-Meier analysis. The probability of survival was 95.5% after 9 years; 35 CEREC® restorations were judged as failures. The prognosis for success was not significantly influenced by restoration size, tooth vitality, treatment of caries profunda (CP), type of tooth treated, or whether the restoration was located in the maxilla or mandible. The most common type of failure was the extraction of a tooth. In a clinical follow-up light -microscopic examination of 44 randomly selected restorations, an average composite joint width of 236.3 microns was found. 45.1% of the restorations exhibited a perfect margin, and 47.4% of the investigated joint sections showed underfilled margins.

[Dr. Rosenberg’s Note: Both cements and the 3D software have improved by “generations” since this ten study was begun and today’s CEREC® 3D restorations should be even more accurate and last longer.]
 

Nakamura T, Dei N, Kojima T, Wakabayashi K. Division of Oromaxillofacial Regeneration, Osaka University Graduate School of Dentistry, Suita, Japan. tnakamur@dent.osaka-u.ac.jp
Marginal and internal fit of CEREC® 3 CAD/CAM all-ceramic crowns.
Int J Prosthodont. 2003 May-Jun;16(3):244-8.

PURPOSE: The purpose of this study was to examine the effects of the occlusal convergence angle of the abutment and the computer's luting space setting on the marginal and internal fit of CEREC® 3 computer-aided design/manufacturing (CAD/CAM) all-ceramic crowns.

MATERIALS AND METHODS: Mandibular second premolar all-ceramic crowns were fabricated for nine different conditions using CEREC® 3: all combinations of abutments with three different total occlusal convergence angles (4, 8, and 12 degrees) with three different luting space settings (10, 30, and 50 micron). The completed crowns were seated on the abutments, and the marginal gaps were measured. The internal gaps between the crowns and abutments were also measured, using test-fit silicone paste.

RESULTS: When the luting space was set to 10 micron, the marginal gaps of the crowns were greater than when it was set to 30 or 50 micron. When the luting space was set to 30 or 50 micron, the marginal gaps ranged from 53 to 67 micron and were not affected by the occlusal convergence angle of the abutment. The internal gaps were within a range of 116 to 162 micron and tended to decrease as the occlusal convergence angle of the abutment decreased.

CONCLUSION: When the luting space was set to 30 micron, crowns with a good fit could be fabricated on the CEREC® 3 system, regardless of the occlusal convergence angle of the abutment.