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: 

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), emphasizes 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 exceptional 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).