The purpose of the study is to compare and evaluate clinical performance between two different bevel preparations in Class IV lesions using nano-filled composite restorations.

The main reason for failure in anterior composite restorations is restoration fracture and aesthetic appearance. Restorations in anterior teeth are subjected to high-impact stresses produced through an incisal angle in class IV restorations, require high fracture resistance. It is the biomechanics of restorations that determine their functionality, retention, and functional longevity. Stair-step chamfer preparation is a modification of chamfer preparation that follows the vertical and horizontal anatomical contours, hence, achieves high degree of aesthetics along with exposure of enamel for bonding. According to current literature, no studies have analyzed the clinical performance of different bevel design using direct nano-filled composite resin restorations in Class IV lesions.

Therefore, the aim of this study is to compare and evaluate clinical performance between two different bevel preparations in Class IV lesions using nano-filled composite restorations.

Study will be conducted at Post Graduate Institute of Dental Sciences, Rohtak in Department of Conservative Dentistry & Endodontics. Time Frame of the study will be 12 months. Patients ≥ 18 years of age with Class IV lesion in maxillary central incisor, lateral incisor due to fracture or primary/ recurrent caries will be enrolled in the study.

After complete carious removal, tooth will be prepared in class IV lesions according to 2mm bevel or 2mm stair-step chamfer preparation group, selective enamel etching and bonding of the tooth using universal adhesive will be done. The cavity will be restored using nanofilled composite by layering technique. The restorations will be undergoing the standard finishing and polishing procedures.

Follow up of patients will be carried out at 3 months for clinical evaluation, 6 and 12 months for both radiographic and clinical evaluation. Restorations will be assessed clinically according to FDI criteria.

Inclusion Criteria:

• Patients ≥ 18 years of age at the time of treatment.
• Class IV lesion in maxillary central incisor, lateral incisor due to fracture or primary/ recurrent caries.
• Patients with complete and normal occlusion and teeth with proximal contacts.
• Patients not having periodontal or pulpal diseases.
• Positive response to the cold test and electric pulp test.

Exclusion Criteria:

• Patients with immunocompromised status or debilitating systemic diseases.
• Patients with uncontrolled parafunctional habits.
• Class IV lesion with involvement of pulp.ix
• Class IV lesions with no involvement of dentin.
• Patients presenting extremely poor oral hygiene.
• Patient with high caries index