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Compendium
May 2016
Volume 37, Issue 5
Peer-Reviewed

Discussion

A key disadvantage of the traditional approach commonly used to treat patients with substantial erosive lesions is the extensive tooth preparation required for conventional crowns.6,7 In particular, the reduced crown height of eroded teeth complicates prosthodontic treatment, because it means there is less remaining tooth structure, which is needed for retention. The extensive removal of tooth structure during conventional crown therapy often results in endodontic treatment and can compromise the long-term survival of the dentition, which is especially relevant when patients are relatively young. In contrast, adhesive restorations represent a more conservative treatment approach, reducing the need for preparation. Superficial preparation of the eroded tooth structure with diamond burs is recommended to ensure adequate surface roughening to enable reliable long-term bonding.9

Data on the performance of composite restorations in patients with severe erosive tooth wear are scarce and contradictory. Recent data are available only in case reports, case series,10 and a retrospective clinical study,11 but they document favorable mid-term results (3.98-year and 5.5-year survival rates of 93.1% and 99.2%, respectively) for adhesively bonded direct composite restorations. However, these chairside treatments using direct composites are time consuming and highly dependent on the operator’s skills. Moreover, deterioration with respect to marginal quality, marginal discoloration, surface texture, and anatomic form was observed. Hence, novel CAD/CAM composite-based material systems, such as resin nanoceramic and hybrid ceramics with enhanced wear resistance and mechanical properties, were developed in an effort to improve the long-term performance of extended restorations for erosive lesions in the load-bearing area. No scientific evidence, however, is available on these materials for the restoration of erosive wear.

Another minimally invasive treatment approach uses palatal indirect composite restorations and facial feldspathic ceramic veneers to restore anterior teeth with severe erosion. While this concept showed favorable results (100% 4-year survival rates) in a prospective clinical study, to date it has been implemented in only one study center; therefore, the success of its use in general remains unclear.12

All-ceramic restorations have a long history of clinical success in minimally invasive rehabilitation of the anterior and posterior dentition. For restoration of carious lesions, promising outcomes are reported for minimally invasive crowns (99.01% 3-year survival rates)13 and posterior restorations (97% to 100% 7-year survival rates).14 To the authors’ knowledge, no prospective, randomized clinical study on erosive lesions has yet been reported in the dental literature.

In the present case, conventional impressions were made, as only limited data are available regarding the precision of full-arch scans.15 Inaccuracies, distortions, and horizontal deviations have been reported in laboratory studies, particularly in the distal portions of the data sets.16

Emerging advantages of the digital technique described in this case report include reduced treatment time and a shorter manufacturing process. The predictability of the final treatment can also be enhanced because of the easy transfer from the planning to the definitive restoration. The virtual diagnostic tooth arrangement was used to manufacture the preparation splints as well as the temporary and permanent restorations, and it needed to be made only once. Moreover, it could be replicated and easily modified. Hence, the treatment was concluded in fewer appointments. The implementation of computer technology allowed for the expectation of highly predictable, precise, reliable restorations. The application of CAD wax enabled the machinability of thin margins of the minimally invasive restorations with a CAD/CAM milling device. The digital approach ensured a cost- and time-effective workflow. Consequently, this method could make the comprehensive treatment of erosive decay accessible to a wider patient population.

Conclusion and Clinical Significance

Defect-oriented adhesive monolithic restorations with reduced ceramic thicknesses represent an esthetic, functional, and minimally invasive treatment option for the rehabilitation of complex cases with erosive defects. In this case, the application of CAD/CAM technology efficiently facilitated treatment planning and restoration fabrication and provided the clinician with guidelines to successfully implement the presented minimally invasive treatment concept. The virtual wax-up, milled preparation splints, CAD/CAM provisionals, and wax patterns of the final lithium-disilicate ceramic restorations provided for a highly predictable and esthetic treatment outcome that was achieved in a timely and cost-effective manner. Long-term clinical studies on the performance of this CAD/CAM workflow are needed.

Disclosure

Enrico Steger, MDT, is founder and CEO of Zirkonzahn GmbH.

About the Authors

Petra C. Guess Gierthmuehlen, DDS
Professor and Chair
Department of Prosthodontics
School of  Dentistry
Heinrich-Heine University
Düsseldorf, Germany

Enrico Steger, MDT
Dental Laboratory Steger
Bruneck, Italy
Founder and CEO
Zirkonzahn GmbH, Gais, Italy

References

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2. Jaeggi T, Grüninger A, Lussi A. Restorative therapy of erosion. Monogr Oral Sci. 2006;20:200-214.

3. Bartlett DW, Lussi A, West NX, et al. Prevalence of tooth wear on buccal and lingual surfaces and possible risk factors in young European adults. J Dent. 2013;41(11):1007-1013.

4. West NX, Sanz M, Lussi A, et al. Prevalence of dentine hypersensitivity and study of associated factors: a European population-based cross-sectional study. J Dent. 2013;41(10):841-851.

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7. Edelhoff D, Sorensen JA. Tooth structure removal associated with various preparation designs for posterior teeth. Int J Periodontics Restorative Dent. 2002;22(3):241-249.

8. Guess PC, Schultheis S, Wolkewitz M, et al. Influence of preparation design and ceramic thicknesses on fracture resistance and failure modes of premolar partial coverage restorations. J Prosthet Dent. 2013;110(4):264-273.

9. Zimmerli B, De Munck J, Lussi A, et al. Long-term bonding to eroded dentin requires superficial bur preparation. Clin Oral Investig. 2012;16(5):1451-1461.

10. Attin T, Filli T, Imfeld C, Schmidlin PR. Composite vertical bite reconstructions in eroded dentitions after 5.5 years: a case series. J Oral Rehabil. 2012;39(1):73-79.

11. Hamburger JT, Opdam NJ, Bronkhorst EM, et al. Clinical performance of direct composite restorations for treatment of severe tooth wear. J Adhes Dent. 2011;13(6):585-593.

12. Grütter L, Vailati F. Full-mouth adhesive rehabilitation in case of severe dental erosion, a minimally invasive approach following the 3-step technique. Eur J Esthet Dent. 2013;8(3):358-375.

13. Cortellini D, Canale A. Bonding lithium disilicate ceramic to feather-edge tooth preparations: a minimally invasive treatment concept. J Adhes Dent. 2012;14(1):7-10.

14. Guess PC, Selz CF, Steinhart YN, et al. Prospective clinical split-mouth study of pressed and CAD/CAM all-ceramic partial-coverage restorations: 7-year results. Int J Prosthodont. 2013;26(1):21-25.

15. Ender A, Mehl A. In-vitro evaluation of the accuracy of conventional and digital methods of obtaining full-arch dental impressions. Quintessence Int. 2015;46(1):9-17.

16. Patzelt SB, Emmanouilidi A, Stampf S, et al. Accuracy of full-arch scans using intraoral scanners. Clin Oral Investig. 2014;18(6):1687-1694.

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