In addition to PEEK, new coatings based on PMMA or composite materials (Anaxblent®Anaxdent®, Nexco®Ivoclar®, Solidex®Shofu®, Novo.lign®Bredent®, etc.) which incorporate ceramic fillings have been developed. Due to their molecular structure, these materials have excellent density and homogeneity [24]. The micro filling integrated into the polymer matrix increases abrasion resistance, at the same time as providing optimal elasticity which resembles the natural structure of a tooth. Although these restorations show good colour stability and a long-lasting shine, texture and brightness, they differ substantially from ceramic coatings which have excellent optical properties that enable them to achieve better long-term aesthetic results.

None of the authors have any competing interests in the manuscript. All authors have performed important contribution and have read and approved the final version to be published.