Secure bonding of CAD/CAM materials: A compact clinical guideline

For the clinical long-term stability of full ceramic restorations, a resilient and reliable adhesion after adhesive fixation is essential. However, different materials must be conditioned and adhered appropriately for the material. Dr. Julián Conejo (University of Pennsylvania, School of Dental Medicine, Philadelphia, USA) explains step-by-step the material-specific protocols for feldspar, glass, hybrid, and zirconia ceramics and demonstrates the differences.

Selection of the bonding system

"An adhesive bonding is indispensable for feldspar and hybrid ceramics," according to the recommendations of clinicians. Although full crowns of zirconia-reinforced lithium silicate glass ceramics and zirconia can also be conventionally cemented, Julián Conejo recommends this procedure only in the case of a retentive dissection form and in treatment situations with suboptimal drainage.

Conditioning the tooth substance

Julián Conejo performs the clinical conditioning steps as follows: "If the dissection is mainly in the enamel, I allow the phosphoric acid to act for 20 seconds. After that, I apply the adhesive components." If the dissection is in the dentine, he recommends a self-etching bonding system. "No phosphoric acid is required for these adhesive systems, which prevents sensory disturbances after the adhesive conditioning," says Julián Conejo.

Conditioning the restoration

"To obtain friction, feldspar and hybrid ceramics must be etched with hydrofluoric acid for 60 seconds, and zirconia-reinforced lithium silicate glass ceramic for 20 seconds," reports the dentist and scientist. He further explains, "A rough surface of the ceramic restoration is necessary for a good micromechanical retention. If this step is omitted, it can lead to adhesive failure." The silane bonding agent should be massaged in for 60 seconds to achieve a chemical bond to the restoration material.

Protocol for zirconia

Julián Conejo points out the deviating conditioning protocol for zirconia: "This material  should be sandblasted for 20 seconds with an  alumina grain size of 30 to 50 micrometers and  less than 2.8 bar." A primer (bonding agent) with the phosphate monomer MDP is  recommended for a high adhesion to zirconia.

Summary

"Every step is of great importance for the adhesive incorporation of ceramic restorations," according to Julián Conejo's conclusion on adhesive bonding. The flawless surface of the restoration should be properly conditioned. The instructions for use of the adhesive and bonding systems have to be followed, and only a careful  drainage of the working field allows a reliable adhesive attachment.

Report 08/16

Dr. Julián Conejo, Dentist
Philadelphia, USA
"Everything must be bonded harmoniously, specific to the material!"
Dr. Julián Conejo, Dentist
Philadelphia, USA
Fig. 1: Conditioning and bonding of different ceramic materials in overview.
Fig. 1: Conditioning and bonding of different ceramic materials in overview.
Fig. 1: Conditioning and bonding of different ceramic materials in overview.
Fig. 2: Insufficient composite and amalgam filling of tooth 16.
Fig. 3: Stump construction and dissection of tooth 16.
Fig. 2: Insufficient composite and amalgam filling of tooth 16.
Fig. 3: Stump construction and dissection of tooth 16.
Fig. 2: Insufficient composite and amalgam filling of tooth 16.
Fig. 3: Stump construction and dissection of tooth 16.
Fig. 4: The virtual model of the dissection.
Fig. 5: Computer aided design of the full crown.
Fig. 4: The virtual model of the dissection.
Fig. 5: Computer aided design of the full crown.
Fig. 4: The virtual model of the dissection.
Fig. 5: Computer aided design of the full crown.
Fig. 6: The virtual restoration placed in the block.
Fig. 6: The virtual restoration placed in the block.
Fig. 6: The virtual restoration placed in the block.
Fig. 7: The final cemented VITA ENAMIC crown.
Fig. 7: The final cemented VITA ENAMIC crown.
Fig. 7: The final cemented VITA ENAMIC crown.
Fig. 8: Palatal view on the dissection margins.
Fig. 8: Palatal view on the dissection margins.
Fig. 8: Palatal view on the dissection margins.
Fig. 9: X-ray control after final cementing.
Fig. 9: X-ray control after final cementing.
Fig. 9: X-ray control after final cementing.

We also use third-party cookies to optimize the website and provide information tailored to your interests. By using this website, you consent to the use and storage of cookies. For detailed information on the use of cookies on this website, click more information. You may also object to the use of cookies here.