This study will be conducted to evaluate the clinical, radiographic and periodontal performance of bioactive Giomer compared to nanohybrid resin composite restoration in deep subgingival proximal cavities extending below the CEJ over a period of 24 months.

Background and rationale:

Recent development in different adhesive techniques and materials has led clinicians to attempt restoring teeth with subgingival defects below the cemento-enamel junction (CEJ). Deep marginal elevation (DME) or cervical margin relocation (CMR) is a procedure that involves raising the proximal margin of the tooth defect with direct composite to promote isolation and restoration using direct, semi-direct or indirect techniques. A high level of knowledge and clinical expertise are necessary to perform such procedure in a predictable way in addition to meticulous attention to the supracrestal tissue attachment or the biological width which consists of junctional epithelium and supracrestal connective tissue attachment.

Research question:

In young and middle-aged patients having deep subgingival proximal cavities extending below CEJ, will the bioactive Giomer show similar clinical, radiographic and periodontal performance compared to nanohybrid resin composite over 2 years follow up?

Statement of the problem:

Carious lesions that extend in subgingival areas present several difficulties for the clinician. Firstly, applying rubber dam in deep cavities and the process of trying to obtain a gingival margin free of caries are very challenging. Secondly, there is a great biological concern to master the subgingival restoration reaction with the adjacent periodontal tissues. Obtaining a healthy periodontal status after treatment has long been a challenging endeavor in the restorative dentistry. Lastly, bonding to deep, carious, and moist dentin surrounded by cementum is inherently suboptimal. To overcome these problems, many techniques and materials were presented to deal with such complex restorative situations. Because of their chemical adherence to the tooth structure, fluoride release and hydrophilicity glass ionomer cements are a reliable option for cementum margins and deep dentin bonding. Marginal defects appearing at the cervical margins due to the solubility property of the material was the main problem the dentist faced in these situations. On the other hand, resin composites are a dependable choice in these circumstances due to their higher mechanical qualities and the way their composition has improved, however, poor material bonding in subgingival margins along with high polymerization stresses associated with them have made it a very complicated procedure.

Rationale for conducting the research:

The use of fluoride releasing dental materials in deep carious lesions was explored before to remineralize the surrounding tooth structure and allow for a more durable restoration with increased resistance to the development of secondary caries. The introduction of Giomers, which combines resin composite and glass ionomer modes of action by Shofu, (Inc.) in the early 2000s was due to the revolutionary surface prereacted glass-ionomer (S-PRG) filler technology that allowed for improved resistance to recurrent caries development. Therefore, this type of bioactive system, adhesive and restoring materials, was claimed to enhance the outcome of deep subgingival restoration clinically, periodontally, and radiographically.

Inclusion Criteria:

1. Young and middle aged patients (20-50)
2. Good or moderate oral hygiene (plaque index 0 or 1 )
3. Patient approval
4. Absence of parafunctional habits and/or bruxism

Exclusion Criteria:

1. Patients with known allergic or adverse reaction to the tested materials.
2. Systematic disease that may affect participation.
3. Xerostomic patients.
4. Patients with active periodontal disease.
5. Heavy smokers