Harvest EasyGum® Use for definitive restorations

EasyGum^® Use for definitive restorations 
 (by Dr. Ceci Marciano, Dr. Zaza Gomurashvili and Jörg Erxleben)

EasyGum™ has proven to be an efficient material that saves time and makes it easier to achieve great aesthetic results in your lab when doing gingiva characterization on provisional materials like PMMA.  

The question arises: is it possible to use EasyGum™ on definitive materials?

 Based on the below research, EasyGum™ is viable for use with Zirconia and other materials in definitive use when you follow recommended protocols. (See EasyGum IFU) 

There are 3 critical components outlined in this paper for EasyGum use as a definitive restoration: 

1. 1. SANDBLASTING the surface before the use of EasyGum Bond 

2. 2. USE of EASYGUM BOND for 17.5MPa bond strength which is 3.5x the ISO requirements for bonding.  

3. 3. POLISHING of the EasyGum surface for plaque & bacteria resistance.  

Veneering ceramics, metal-ceramics, or zirconia with composite materials for dental applications has always been a challenge for the clinical practitioner with the products available on market. However, today, many systems promise to be functional and stable for 5-10 years, even in occlusal restorations.  

Kimura and colleagues (2019), emphasize the importance of proper surface preparation and the choice of bonding materials to achieve optimal bond strength between veneers and zirconia frameworks. 

Özcan et. al. (2013 found that sandblasting with 30 μm aluminum trioxide particles coated with silica resulted in the highest bond strength of resin composites to zirconia cores measured after 6,000 thermocycles. 

Sarfaraz et al. (2020) compared the bond strength of composite resin to Zirconia and PEEK in Vitro before and after 5,000 thermocycles and the results suggest that the pretreatment method and primers used were effective. 

Meirelles et al (2020) reported a case of a chipped porcelain-zirconia restoration that was repaired with a composite resin reconstruction observed the repair for 5 years. The restoration stayed intact without visible deterioration. 

Saravia-Rojas and Geng-Vivanco (2022), reported a case of an intraoral repair of a chipped crown with the debonding of the feldspathic ceramic veneer and exposure of the zirconia framework. Per their study the repair can be performed with composite resin or cementing the fractured ceramic fragment with light-cured resin cement, like in their case. The patient reported after 10 years that the crown was functional and esthetic. 

Komine et al. (2013) found that the application of a combination of hydrophobic phosphate monomer (MDP) and initiator results in a durable long-term bond between zirconia and C&B composite material. 

SANDBLASTING:  

Considering these studies, we recommend the following protocol for bonding EasyGum™ to Zirconia as a standard surface treatment: Sandblasting the Zirconia surface with 30 μm SiO₂ coated Aluminum Oxide prior to application of the EasyGum Bond agent is the most recommended procedure.  

USE of EASYBOND: 

Based on the literature review, we expect EasyGum™ to be viable for definitive use with Zirconia when carefully following the recommended protocol for bonding. The EasyGum Bond provides an exceptionally high bond strength of 17.5 MPa to zirconia (According to our internal data), which is 3.5 times higher than the ≥ 5 MPa demanded by the ISO 10477:2004 standard. 

POLISHING: 

Smooth and highly polished surface finish of the composite restoration is the main factor in bacterial plaque adhesion to the material. Based on the literature review, the final surface roughness in composites is related to three factors: filler size, filler integration and surface finish. 

Kawai et al. (2001) showed that polishing reduced the plaque adherence by half (from 4700 on rough finish to 2700 cells on polished composite). 

Pereira et al. (2011) found that the Nano-Particle Composite had the lowest bacterial adherence with each of the finishing and polishing techniques. 

Derchi et al. concluded that Indirect dental restorative composite resins were found to be less prone to biofilm adhesion than direct composite resins 

EasyGum™ is made of easy to polish polymer matrix and, very important, a filler which is less than 50nm in size and so provides a smooth and easy to polish surface. This special characteristic and the advantage of being used in indirect restorations leads to less Plaque Adhesion and so to a longer lifetime in the patient’s mouth. 

References: 

1. Fumiaki Kimura et. al.  (2019). Bond strength of CAD/CAM-manufactured composite resin and ceramic veneers to a zirconia framework. Journal of Oral Science, Vol. 61, No. 2, 327-334. 

2. Mutlu Özcan et. al. (2013). Effect of Surface Conditioning Modalities on the Repair Bond Strength of Resin Composite to the Zirconia Core / Veneering Ceramic Complex. The Journal of Adhesive Dentistry, Vol 15, No 3, 207-210.  

3.  Sarfaraz H, Rasheed M, Shetty SK, Prabhu UM, Fernandes K, Mohandas S.  Comparison of the bond strength of composite resin to zirconia and composite resin to polyether ether ketone: An in vitro study. J Pharm Bioall Sci 2020;12:S504-9 

4. Meirelles PD, da Rocha LS, Pecho OE, Della Bona A, Benetti P; Intraoral repair of a chipped porcelain-zirconia restoration. J Esthet Restor Dent. 2020;1–7 

5. Saravia-Rojas MA, Geng-Vivanco R. Clinical protocol for intraoral repair of a chipped all-ceramic crown: a case report. Gen Dent. 2023 Jan-Feb;71(1):54-57 

6. F Komine, K Kobayashi, MB Blatz, R Fushiki, M Koizuka, K Taguchi, H Matsumura; Durability of bond between an indirect composite veneering material and zirconium dioxide ceramics. Acta Odontologica Scandinavica, 2013 

7. Kawai K., Urano M., Adherence of Plaque Components to Different Restorative Materials; Operative Dentistry, 2001, Vol. 26, 396-400  

8. CA Pereira E Eskelson V Cavalli PCS Liporoni AOC Jorge MA do Rego, Streptococcus mutans Biofilm Adhesion on Composite Resin Surfaces After Different Finishing and Polishing Techniques, Operative Dentistry, 2011, Vol. 36-3, 311-317 

9. G Derchi, M Vano, A Barone, U Covani, A Diaspro, M Salerno; Bacterial adhesion on direct and indirect dental restorative composite resins: An in vitro study on a natural biofilm J Prosthet Dent 2017;117:669-676