The aim of this study was to compare the clinical performance over 1 year of a microhybrid composite resin for class V restorations both lined and not lined with a flowable composite resin. Nineteen patients having at least two pairs of cervical noncarious lesions under occlusion were enrolled in this study. A total of 38 restorations were placed, half for each group (Single-Bond + Filtek-Flow + Filtek Z250, and Single-Bond + Filtek Z250). Two calibrated operators placed all restorations according to the manufacturers' instructions. Two other independent examiners evaluated the restorations at baseline and after a 12-month period according to the USPHS criteria and modified criteria for color match. The classic alpha score was divided into A1 for "not detectable" and A2 for "slightly discernible" filling. Statistical analysis was conducted using Fisher's exact test and McNemar's test (P=0.05). One restoration was lost after 12 months for each group (retention rate 95% for each group). After 12 months, 18 restorations showed a trend towards dark yellowing (color match A2). The use of Filtek Flow as a liner under Filtek Z250 restorations did not improve the clinical performance of class V restorations after 6 and 12 months of evaluation.