ORIGINAL ARTICLE Three-year clinical evaluation of high-viscosity glass ionomer restorations in non-carious cervical lesions: a randomised controlled split-mouth clinical trial Esra Uzer Celik 1 & Ayse Tugce Tunac 2 & Fatma Yilmaz 3 Received: 4 March 2018 /Accepted: 9 August 2018 # Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract Objective To compare the 3-year clinical performance of high-viscosity glass ionomer restorations with that of composite restorations in non-carious cervical lesions (NCCLs). Materials and methods One hundred thirty-four NCCLs were randomised into two groups according to a split-mouth design. In the experimental group (Hv-GIC), lesions were restored with a high-viscosity glass ionomer (EQUIA Fil, GC), whereas a composite resin (G-aenial, GC) was applied in the control group (E&Ra/comp). All restorative materials were used according to the manufacturers’ instructions. Clinical evaluations were performed after 1 week, 6 months, 1 year, 2 years, and 3 years using FDI (World Dental Federation) criteria. Data were analysed using Friedman’ s ANOVA and Mann-Whitney U tests (α = 0.05). Results While retention rates of the Hv-GIC group were 98.5%, 96%, 91%, and 87% in respective evaluation periods, no retention loss was observed in the E&Ra/comp group at any time. There was a statistically significant difference between study groups regarding the retention criterion in both the second and third years (p = 0.008 and p = 0.003, respectively). Furthermore, there was a statistically significant difference between the groups in terms of surface lustre at the third-year recall, in favour of the E&Ra/comp group (p = 0.022). Conclusions The 3-year clinical performance of E&Ra/comp restorations in NCCLs was better than that of Hv-GIC restorations. The most common problems in Hv-GIC restorations were a loss of retention and reduction in surface lustre. Clinical relevance Although the 3-year clinical performance of Hv-GIC restorations in non-retentive lesions was acceptable, it was worse than in composites. The operator should consider the benefit/loss ratio of Hv-GIC when he/she decides to use this material in non-retentive cavities, especially those that are shallow. Keywords High-viscosity glass ionomer . Non-carious cervical lesions . Composite resin . Clinical performance Introduction Non-carious cervical lesions (NCCLs) are characterised by loss of hard tissue at the cementoenamel junction in the absence of caries that is commonly caused by both patholog- ical and physiological tooth wear [1]. According to etiological factors, NCCLs are categorised as abrasion, erosion, and abfraction lesions [2]. The prevalence of these lesions is in- creasing, especially among both adolescents and older adults [3]. In particular, increased consumption of acidic drinks among youths and the higher amount of medications taken by older adults increase the risk of NCCLs [4, 5]. NCCLs may require intervention at any time throughout a patient’ s life due to the risk of caries occurrence, tooth fracture, hyper- sensitivity, and aesthetic problems. The restoration of NCCLs is a commonly preferred treatment choice in the presence of uncontrolled hypersensitivity, poor aesthetic appearance, un- controlled plaque retention, clear lesion progression, and in- creased cervical caries risk [6]. However, clinical success is difficult with restorative treatment because of stress * Esra Uzer Celik esrauzer@yahoo.com 1 Department of Restorative Dentistry, Faculty of Dentistry, İzmir Katip Çelebi University, Aydınlıkevler Mah, Cemil Meriç Caddesi, 6780 sok. No:48, 35640 Çiğli, Izmir, Turkey 2 Department of Restorative Dentistry, Faculty of Dentistry, Yeditepe University, Istanbul, Turkey 3 Department of Restorative Dentistry, Faculty of Dentistry, Pamukkale University, Denizli, Turkey Clinical Oral Investigations https://doi.org/10.1007/s00784-018-2575-y