Bonded for good fortune: Seven-year medical efficiency of CAD/CAM lithium disilicate restorations with adhesive cementation.

On the College of Washington, a 7-year potential medical investigation has equipped treasured long-term insights into the efficiency of lithium disilicate CAD/CAM restorations in posterior tooth. Performed through Prof. John A. Sorensen and his staff, the learn about evaluated 50 IPS e.max CAD restorations fabricated with a completely virtual workflow and adhesively bonded with Adhese Common and Variolink Esthetic DC. With a Kaplan–Meier survival charge of 94.5% after as much as seven years, the findings underline the reliability of adhesive, teeth retaining approaches in fashionable prosthodontics (Sorensen, Chen & Sadr 2025).

Some great benefits of lithium disilicate in posterior restorations. 

Q&A with Dr. John Sorensen.

Q: Out of your medical standpoint, what are the important thing benefits of lithium disilicate ceramics akin to IPS e.max CAD, particularly for posterior restorations, in comparison to different ceramic subject matter?

Sorensen: Above all, the conservation of teeth construction is maximum essential. Adhesive ceramics like lithium disilicate let us keep considerably extra herbal teeth construction than conventional full-crown restorations. In research that Prof. Daniel Edelhoff and I carried out about 25 years in the past, we demonstrated that even probably the most competitive veneer design required near to part the teeth construction relief of a complete crown (Edelhoff & Sorensen 2002a). In posterior tooth, a 5-surface ceramic onlay design confirmed a identical outcome—kind of 50% much less relief (Edelhoff & Sorensen 2002b.).

We started with leucite-reinforced glass-ceramics, akin to IPS Empress, which had a flexural power of about 165 MPa and completed very good medium- and long-term effects when adhesively cemented (Sorensen et al. 1998). With IPS e.max CAD lithium disilicate, we reached flexural strengths of round 475–500 MPa and progressed fracture toughness. Consistent with producer knowledge and showed through long-term interior high quality trying out over ten years, the common flexural power of IPS e.max CAD is roughly 530 MPa. Adhesive cementation additional complements the general outcome through making a ceramic/adhesive cement/teeth advanced, conferring remarkable medical longevity – even at diminished wall thickness.

Our in vitro and medical knowledge additionally display that correctly polished lithium disilicate demonstrates put on conduct related to forged gold alloys (Sorensen et al. 2011; Sorensen 2013). And naturally, its optical houses are unequalled – it merely seems like teeth. For single-tooth restorations, lithium disilicate stays the perfect selection.

Key components for long-term adhesive good fortune

Q: What are probably the most crucial steps in adhesive cementation protocols to make sure the long-term good fortune of conservative onlay arrangements?

Sorensen: Ahead of discussing bonding, we will have to ensure that good enough ceramic thickness. For many years, my usual working process has been to make use of the transient recovery as the prototype for the general one. After occlusal adjustment, I measure thickness at key issues the use of calipers to make sure the preparation intensity. When it comes to milled restorations, we wish to imagine that the smallest milling bur is 0.6 mm – subsequently, sharp interior line angles will have to be have shyed away from to forestall overmilling.

With regards to cementation, six components are crucial:

1. Removing of transient cement: Each and every hint will have to be got rid of; even residual pumice from cleansing can save you whole seating.
2. Isolation: Moisture keep an eye on is non-negotiable. Saliva contamination after etching vastly reduces bond power.
3. Meticulous adhesive dealing with: Apply the producer’s protocol precisely – etching time, lively rubbing, air-thinning and curing. When the use of Adhese Common, totally disperse the bonding agent with compressed air so no liquid stays, and watch out to steer clear of pooling in line angles.
4. Steer clear of accumulation of extra adhesive: For the reason that protocol requires photo-polymerization of adhesice previous to cementation, if extra subject matter is cured it could possibly save you whole seating of the recovery
5. Take away extra cement ahead of curing: For the reason that 1990’s, even right through our IPS empress and Empress 2 bridge research (Sorensen et al. 1999), I’ve used micro brushes and waxed floss to take away extra ahead of polymerization. If resin cement stays within the gingival embrasure, it could possibly set and turn into just about unattainable to take away. 
6. Ultimate Test: After curing, run unwaxed floss via contacts – if it frays that signifies that cement fragments stay and will have to be got rid of. 

In my enjoy, those steps – although apparently small – make the adaptation between reasonable and very good results in adhesive restorations. 

Scientific enjoy with Variolink Esthetic DC and Adhese Common

Q: In accordance with your ling enjoy, how do you assessment the long-term efficiency of Variolink Esthetic DC and Adhese Common in extremely wired posterior spaces? 

Sorensen: My enjoy with Variolink cements spans mroe than 30 years. Throughout my PhD research in 1992-1997, I evaluated polymerization conduct in dual-curing and light-curing cements, and the unique Variolink carried out exceptionally properly (Sorensen & Munksgaard 1995; 1996). As of late, the fashionable Variolink Esthetic DC continues that legacy of reliability with progressed esthetics and dealing steadiness. Even after  extended garage, it maintains a constant operating time – crucial when cementing a couple of veneers or onlays concurrently. 

When assessing high-stress areas, akin to 2nd molars, which enjoy as much as 3 times the chunk pressure of central incisor, power and adhesive bonding turn into decisive. 

In our 7-year medical learn about involving 35 onlays and 15 crowns, all fabricated digitally and cemented with Variolink Esthetic DC, we noticed 94.5% medical good fortune charge, confirming the long-term reliability of this answer beneath posterior load. By the way, one of the most two recovery occurrred through a affected person biting right into a stone in his meals which fractured the onlay. The mix of IPS e.max CAD and confirmed adhesive cementation give clinicians self belief of their long-term results. 

Indications and medical variety

Q: Which varieties of medical instances are particularly well-suited for adhesive cementation of lithium disilicate CAD?CAM restorations? 

Sorensen: First, any teeth recovery that has now not prior to now been handled with a complete crown. My philosophy is understated: keep teeth anywhere imaginable. For anterior and premolar restorations, I most often use veneer-type arrangements with 0.5-0.6 mm chamfer margins. 

For posterior tooth with huge composite fillings or cracks, particularly mandibular molars with distal marginal ridge cracks (cracked teeth syndrome), lithium disilicate onlays are splendid. By means of restoring the structural integrity of posterior tooth adhesive ceramic onlays make stronger closing teeth construction with out competitive preparation. 

When blockading out undercuts, I take advantage of glass ionomer bases as a result of their thermal expansioncoefficient is closest to dentin. It makes little sense to take away all interior geometry that improves retention and floor space for bonding. 

Lithium disilicate could also be the fabric of selection for full-mouth rehabilitiations requiring higher occlusal vertical size. Its excessive bond power after hydroflouric acid etching, mixed with enamel-like translucency, makese it splendid for conservative reconstructions. 

Zirconia, even with MDP-based cements, most often achieves handiest 40-50% of the bond power of etched lithium disilicate (Sorensen & Chen; Bitsis 2015). 

Virtual Workflow and marginal constancy

Q: Your learn about additionally emphasised some great benefits of a completely virtual workflow. What are probably the most related findings on this regard?

Sorensen: The accuracy of recent virtual workflow is outstanding. The use of intraoral optical scanning (Trios 3, 3Shape), digital design (Dental Design, 3Shape) and IPS e.max CAD milling, we produced restorations with imply marginal discrepancies of simply 73 μm no supporting cusp shoulder margins and 53 μm on non-supporting cusp bevels, verified with optical coherence tomography (OCT) imaging (Sorensen, Hayashi & Sadr 2019). Those are awesome to many conventionally fabricated restorations. 

In our as much as 7-year trial, we additionally recorded time financial savings. Within the center 3rd of instances, about 40% of restorations required no proximal or occlusal adjustment. Within the ultimate 3rd, that quantity rose to 87% (Sorensen et al. 2025). Changes, when wanted, most often took just one or two mins.

This degree of accuracy has massive implications for medical potency. In early instances, we allotted an hour for supply and cementation; later, maximum had been completed in quarter-hour. Those beneficial properties in productiveness and predictability in reality exchange the workflow for restorative dentistry.

As CAD/CAM techniques evolve with quicker milling and AI-assisted scanning, we will be expecting even larger potency and precision within the close to long term.

Long term Developments

Q: What inventions or tendencies in adhesive protocols or CAD/CAM ceramics could have the best have an effect on on restorative dentistry within the coming years?

Sorensen: The evolution of virtual mounted prosthodontics continues at an outstanding tempo. Chairside techniques are quicker and extra actual; instrument integration between clinicians and laboratories helps to keep making improvements to.

The larger paradigm shift, although, is the rising medical self belief in conservative adhesive restorations. Many clinicians nonetheless make a choice complete crowns, particularly zirconia,
as it feels more secure and more effective. But long-term knowledge display that adhesively bonded ceramics, when used as it should be, are similarly dependable and way more tooth-conserving.

A number of research, together with ours, point out a considerably decrease prevalence of root canal treatment and postoperative sensitivity in adhesive onlays in comparison to complete crowns
(Edelhoff & Sorensen 2002; Sorensen et al. 2022).

Our 7-year knowledge obviously exhibit that IPS e.max CAD restorations adhesively bonded with Adhese Common and Variolink Esthetic DC supply solid adhesive interfaces, very good marginal adaptation and dependable medical efficiency even beneath posterior
stresses. I imagine the combo of adhesive lithium disilicate ceramics and an exact virtual workflow gives the very best steadiness of power, potency and the best possible esthetics– and will stay a cornerstone of recent restorative apply for years yet to come.

Conclusion

The 7-year College of Washington learn about led through Prof. Sorensen gives tough medical proof for the long-term reliability of adhesive lithium disilicate restorations. With a 94.5% survival charge and minimum marginal degradation (Sorensen et al., IADR J Dent Res 2025 Ab #1214), IPS e.max CAD restorations cemented with Adhese Common and Variolink Esthetic DC have demonstrated very good sturdiness, esthetics and bond steadiness – even in high-stress posterior programs.

As Prof. Sorensen emphasizes, the synergy of virtual precision, adhesive power and minimally invasive remedy approaches marks a brand new usual in mounted prosthodontics – one the place potency and longevity move hand in hand with minimally invasive care.

We thank Prof. Sorensen for sharing his insights and long-term medical enjoy in adhesive dentistry.

Symbol Review

© John A. Sorensen. Posterior IPS e.max CAD onlay on teeth 30 (46) after 7.5 years in serve as (lingual and quadrant)

References

Edelhoff D, Sorensen JA.Teeth construction removing related to quite a lot of preparation designs for anterior tooth. J Prosthet Dent 2002a;87:503–509.

Edelhoff D, Sorensen JA.Teeth construction removing related to quite a lot of preparation designs for posterior tooth. Int J Periodontics Restorative Dent 2002b;22:241–249.

Sorensen JA, Chen Y-W, Sadr A. Posterior CAD/CAM adhesive ceramic restorations: 7-year medical learn about standing. J Dent Res 2025; Summary #1214

Sorensen JA, Hayashi J, Sadr A. Scientific trial of OCT imaging of posterior adhesive ceramic restorations. J Dent Res 2019;98:Summary #2811.

Sorensen JA, Chen Y-W, Sadr A. Adhesive ceramics: 2-year medical learn about effects with a cracked teeth center of attention. J Dent Res 2022; Summary #1007.

Sorensen JA, Choi C, Fanuscu MI, Kang SK, Mito WT. IPS Empress crown gadget: Threeyear medical trial effects. J Cal Dent Assoc 1998;26:130-136.

Sorensen JA, Cruz M, Mito WT, Raffeiner O, Meredith HR, Foser HP. A medical investigation on three-unit mounted partial dentures fabricated with a lithium disilicate glassceramic.

Pract Periodont Aesthetic Dent 1999;11:95 -106

Sorensen JA, Munksgaard EC: Interfacial gaps of resin cemented ceramic inlays. Eur J Oral Sci 1995;103:116-120.

Sorensen JA, Munksgaard EC. Relative hole formation of resin-cemented ceramic inlays and dentin bonding brokers. J Prosthet Dent 1996;76:374-378.

Sorensen JA, Chen Y-W. Shearbond power of cements to dentin with various moisture stipulations. J Dent Res 2017;96:Spec.Iss.A, Ab#1616.

Sorensen JA, Sultan EA, Sorensen PN. 3-body put on of teeth towards complete crown ceramics. J Dent Res 2011;89 Ab#1652.

Sorensen JA. Completing and sharpening of recent ceramic techniques. Within Dentistry 2013;9(1) Particular Factor 1:10-16

Bitsis I. Shear bond power of adhesive cements to zirconia ceramics. MSD 2015, College of Washington.

Dr. John A. Sorensen

Prof. John A. Sorensen, DMD, PhD, FACP, is Professor of Restorative Dentistry on the
College of Washington and Director of the B4T Laboratory. A diplomate of the
American Board of Prosthodontics, he focuses his analysis on adhesive dentistry,
CAD/CAM ceramics, and virtual workflows in medical prosthodontics.

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