14 March 2023

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Wear in CAD-CAM resin ceramic materials: A review of the current state

Lorenzo Breschi

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Introduction

Today, the use of computer-aided design and computer-aided manufacturing (CAD-CAM) systems is increasingly widespread. In the last few years resin-ceramic materials have been developed in order to meet the requirements of minimally invasive dentistry, including the resin nanoceramic (RNC) and polymer-infiltrated ceramic network (PICN). 

Despite that, none of the currently available materials exhibit perfect intraoral stability over time. Regarding the wear resistance, it is strictly related to the characteristics of the ceramic embedded in the matrix. The wear process varies with the etiology (attrition, abrasion, or erosion) but always leads to material loss and topographic changes in the material. However, high hardness and low roughness can improve the resistance of the material to wear. Hybrid materials, such as resin-ceramic, with excellent esthetics, high hardness, and good wear resistance, appear to meet the clinical requirements and indications of those of lithium disilicate reinforced glass-ceramics. 

Recently, Laborie et al. conducted a systematic review to compare the wear resistance of resin-ceramic materials (RNC and PICN), in vitro and in vivo, with other resin-ceramic materials and lithium disilicate (LiSi) reinforced ceramics. 

Materials and methods

Researchers conducted a systematic review by following the preferred reporting item for systematic reviews and meta-analyses (PRISMA) guidelines. The team used PubMed, Scopus and DOSS search engines to identify articles published between 2013 and 2021. Two independent researchers conducted the review process by following PRISMA guidelines and by following a combination of keywords. Researchers considered laboratory and clinical studies in English and French languages evaluating the wear resistance of CAD/CAM manufactured RNC, PICN and LiSi ceramic.

Results

Of the 195 titles obtained from the initial search, only 35 articles were considered eligible. After comprehensive review of the articles, the research team included 23, with three additional articles retrieved from the reference section. Of these, 25 were in vitro studies and only one was a clinical trial. Fifteen studies compared resin-ceramic materials with each other, while 11 compared resin-ceramic materials with LiSi ceramics. 

Two types of wear were used to compare the materials: attrition and abrasion. The most studied materials were two RNCs (Lava Ultimate and Cerasmart), one PICN (Vita Enamic) and one ceramic (IPS e.max CAD). Among the resin-ceramic materials, the PICN (Vita Enamic) showed less wear than the RNCs. Of the RNCs, Cerasmart had less attrition wear and less wear of the opposing teeth.

Conclusions

What emerged from this review is that LiSi glass-ceramics have higher wear resistance than resin-ceramic materials, with CAD-CAM resin-ceramic materials exhibiting different wear resistance properties from each other. Furthermore, LiSi glass-ceramics cause more wear of the opposing teeth. 

Marion Laborie, Adrien Naveau and Aude Menard. “CAD-CAM resin-ceramic material wear: A systematic review.” J Prosthet Dent. 2022 Apr 19: S0022-3913(22)00076-2. doi: 10.1016/j.prosdent.2022.01.027. Epub ahead of print. PMID: 35459543.