The purpose of this double-blind, randomized trial is to compare the clinical performance of a composite restorations in root surface carious lesions with or without resin modified glass ionomer lining.

Thirty-nine patients with at least one pair of equivalent root caries lesions and a mean age of 39.6 years (range 18-65 years; median 39 years) were enrolled in this study. After caries removal, the depth, length, and width of the cavity were measured. Lesions in the same patient was randomly divided into two groups, and the dentin surfaces were either lined with resin-modified glass ionomer liner (Glass liner II, Willmann & Pein GmbH Dental, Barmstedt, Germany) or not. All cavities were restored with nanohybrid composite resin (Clearfil Majesty Esthetic, Kuraray, Tokyo, Japan). A total of 100 restorations (50 lined, 50 unlined) were placed according to manufacturer's instructions. The restorations will be evaluated at baseline and at 6, 12, 24, 36, 48 months and 5-year after placement using the modified Haveman Criteria for marginal adaptation, anatomic form, marginal staining, anatomic form, caries in adjacent tooth structure, caries at the cavosurface margin and sensitivity. Statistical analysis will be conducted using the Chi- Square, Fisher's Exact, Mann Whitney-U and Cochran Q tests at a significance level of 5% (P < 0.05).

Inclusion Criteria:

• Non-hospitalized, healthy patients that were seeking dental treatment for caries lesions on the root surface

Exclusion Criteria:

• Patients who were under the age of 18 years
• Complex medical history
• Severe or chronic periodontitis
• Extreme carious activity
• Heavy bruxism
• Very deep or superficial carious lesions
• Previously restored and abutment teeth