News Feature

Go for a trustworthy ceramic and metal primer

Article by Peter Schouten

Ceramic primers vary widely in composition and effectiveness, despite what their name might suggest. Most common primers include silane, but silane alone is insufficient for pre-treating all materials commonly used in indirect restorations before bonding.

Silane—typically in the form of γ-MPS—has a strong affinity for silica- or glass-based materials. While certain metals and their oxides can chemically react with silane, other components provide a stronger and more reliable bond to metals and metal oxides and should be seriously considered.

For metal(oxide) pretreatment in bonding, the MDP monomer is far more reactive than silane. The original MDP monomer, developed by Kuraray Co., Ltd. in 1981, remains the highest-quality MDP available, as confirmed by research.¹

CLEARFIL™ CERAMIC PRIMER PLUS is a single-component adhesive primer that forms strong bonds with a wide range of restorative materials. This two-in-one primer incorporates the original MDP monomer, which establishes a robust bond with metals and zirconia. Simultaneously, the silane coupling agent (γ-MPS) ensures excellent adhesion to resin composites, hybrid ceramics, and glass-based ceramics such as lithium disilicate and porcelain.

ENHANCED BOTTLE DESIGN

The primer bottle is designed for effortless one-handed operation. Its unique nozzle ensures precise dispensing, minimizing the risk of contamination and spills.

PROVEN EFFECTIVENESS OF MDP-CONTAINING PRIMERS

To enhance the bonding of prosthetic materials, use a primer containing both MDP and silane. Numerous studies have demonstrated the effectiveness of this combination.

A study by Cao, Y., et al² confirmed the superiority of CLEARFIL™ CERAMIC PRIMER PLUS (Kuraray Noritake Dental Inc.) over three other primers in improving the bond strength between zirconia and two different resin cements.	Study by Cao, Y., et al. The effects of four primers and two cement types on the bonding strength of zirconia. - Clearfil Ceramic Primer outperformed three other primers in improving the bond strength between zirconia and two different resin cements.
Reymus, M., et al. concluded in their study³ that before adhesive cementation of air abraded CAD/CAM resin composites, pretreatment with a specific primer, not only containing silane but also methacrylate monomers results in successfully bonded restorations. Pretreatment using an only silane containing primer results in inadequate adhesion.	Findings from Reymus, M., et al. Bonding to new CAD/CAM resin composites: influence of air abrasion and conditioning agents as pretreatment strategy. - Adhesive cementation of air-abraded CAD/CAM resin composites benefits from pre-treatment with a primer containing both silane and methacrylate monomers. - Primers with only silane provided inadequate adhesion, while the combination significantly enhanced bonding success.
Four different types of CAD/CAM ceramic materials where tested in a study by Uğur, M., et al.⁴ Vita Mark II, IPS E.max CAD, Vita Suprinity and Vita Enamic were primed with three different primers CLEARFIL™ CERAMIC PRIMER PLUS, G-Multi Primer (GC) and Monobond S (Ivoclar Vivadent), either after hydrofluoric acid etching or no etching. It was concluded in this study that the combined effects of MDP and γ-MPTS resulted in a significant increase in the bonding strength of the resin cement to the used ceramics.	Research by Uğur, M., et al. Effect of ceramic primers with different chemical contents on the shear bond strength of CAD/CAM ceramics with resin cement after thermal ageing. - Four types of CAD/CAM ceramic materials (Vita Mark II, IPS e.max CAD, Vita Suprinity, and Vita Enamic) were tested with three primers: Clearfil Ceramic Primer Plus, G-Multi Primer, and Monobond S. - Pre-treatment included hydrofluoric acid etching or no etching. Results showed that primers combining MDP and γ-MPTS substantially improved bond strength to ceramics.
Pilo, R., et al. concluded in their study⁵ investigating the effect of tribochemical treatment and silane reactivity on the bonding to zirconia that MDP greatly contributes to the bonding mechanism of the silane containing primers. CLEARFIL™ CERAMIC PRIMER PLUS showed to be the most reliable and effective primer in this study.	Pilo, R., et al. Study Effect of tribochemical treatments and silane reactivity on resin bonding to zirconia. - Examined tribochemical treatment and silane reactivity on zirconia bonding. - MDP significantly contributed to the bonding mechanism of silane-containing primers. - Ceramic Primer Plus was the most reliable and effective primer.
In his study⁶ that forms a part of his well-known dissertation, Masanao Inokoshi and others concluded that a combined mechanical/chemical pre-treatment of sintered IPS e.max ZirCAD (Ivoclar Vivadent) results in the most durable bond to zirconia. In this case when the chemical pretreatment was performed with CLEARFIL™ CERAMIC PRIMER PLUS or Monobond Plus (Ivoclar Vivadent). Scotchbond Universal (3M ESPE) and Z-PRIME Plus (Bisco), also used in this study as chemical pretreatment primers showed significant lower bond strengths.	Research by Masanao Inokoshi Bonding effectiveness to different chemically pre-treated dental zirconia. - Investigated mechanical/chemical pre-treatment of sintered IPS e.max ZirCAD for durable zirconia bonding. - Clearfil Ceramic Primer (Kuraray Noritake) and Monobond Plus (Ivoclar Vivadent) yielded the most durable bonds, outperforming Scotchbond Universal (3M ESPE) and Z-PRIME Plus (Bisco), which showed significantly lower bond strengths.

OPTIMAL PRIMING FOR ADHESIVE CEMENTING

These studies underscore the critical role of MDP-containing primers in achieving reliable and durable adhesion for prosthetic materials. Products containing only silane, such as RelyX™ Ceramic Primer (3M ESPE), are less effective at creating a durable bond between resin cements or composites and ceramic- or metal-based prosthetic materials.

Image from clinical case by MDT Rondoni and Dr. Attanasio

STRAIGHTFORWARD AND EFFICIENT

The use of CLEARFIL™ CERAMIC PRIMER PLUS is straightforward: just apply it to the bonding surface, dry it, and proceed with the following treatment step. Incorporated into your process to streamline adhesion preparation and achieve reliable results!

JUST APPLY AND DRY

CLEARFIL™ CERAMIC PRIMER PLUS may be applied to any restoration surface after the required pretreatment. Pretreat the adherent surface of the restoration as indicated:

* If your laboratory already treated with a hydrofluoric acid, cleaning and activating with K-ETCHANT Syringe just before applying CLEARFIL™ CERAMIC PRIMER PLUS is recommended.

**When using with PANAVIA™ V5 or CLEARFIL™ DC CORE PLUS

Universal prosthetic primer designed for a strong bond and procedural simplicity

Author:

PETER SCHOUTEN

References

1. Yoshihara K., et al.(2015) Functional monomer impurity affects adhesive performance, Dental Materials, Volume 31, Issue 12, https://doi.org/10.1016/j.dental.2015.09.019. Pilo, R., et al. (2018). “Effect of tribochemical treatments and silane reactivity on resin bonding to zirconia.” Dent Mater 34(2): 306-316.
2. Cao, Y., et al. (2021). The effects of four primers and two cement types on the bonding strength of zirconia. Annals of Translational Medicine. 10. 10.21037/atm-21-4909.
3. Reymus, M., et al. (2019). “Bonding to new CAD/CAM resin composites: influence of air abrasion and conditioning agents as pretreatment strategy.” Clin Oral Investig 23(2): 529-538.
4. Uğur, M., et al. (2023). Effect of ceramic primers with different chemical contents on the shear bond strength of CAD/CAM ceramics with resin cement after thermal ageing. BMC Oral Health. 23. 10.1186/s12903-023-02909-z.
5. Pilo, R., et al. (2018). “Effect of tribochemical treatments and silane reactivity on resin bonding to zirconia.” Dent Mater 34(2): 306-316.
6. Inokoshi, M., et al. (2014). “Bonding effectiveness to different chemically pre-treated dental zirconia.” Clin Oral Investig 18(7): 1803-1812.