A clinical trial, comparing the clinical performance and occlusal wear resistance of two different restorative materials in restoring proximal caries in permanent posterior teeth. One is based on giomer technology and the other is nano-hybrid resin composite.

The aim of this study is to assess clinical performance and occlusal wear resistance of low shrinkage Giomer and Nanohybrid Resin Composite in proximal restorations using revised FDI (World Dental Federation) criteria and digital intra-oral scanner.

Two different restorative materials will be evaluated after two years for fracture, retention and occlusal wear. Furthermore, the rest of the revised FDI Criteria including functional (marginal adaptation, proximal contact point, form and contour, occlusion and occlusal wear) , biological (caries at restoration margin (CAR), dental hard tissue defects at restoration margin and postoperative hypersensitivity/pulp status) and esthetic properties (surface luster and surface texture, marginal staining and color match) will be also evaluated.

The first material is based on the giomer technology which is a true hybrid between nano-hybrid resin composite and glass ionomer. The comparator will be a nano-hybrid resin composite.

Examination and selection of all patients will be done. Teeth with proximal, primary carious lesions will be selected. Rubber dam isolation will be done followed by preparation of Class II cavities and placement of restorative material according to the randomization sequence.

Low-shrinkage bioactive material will be applied according to the manufacturer's instructions. For the comparator group, nano-hybrid resin composite will be also applied according to the manufacturer's instructions. Restorations will evaluated at baseline, after six, 12, 18 and 24 months.

Inclusion Criteria:

• Inclusion criteria for patients

  • Patient's age ranging from 19-30
  • Good oral hygiene.
  • Patients who have stable occlusion.
  • Patients who could be present for further periodic follow-ups.
  • Possibility for application of rubber dam during restoration.
  • Patient compliance.

• Inclusion criteria for Teeth

  • Vital first and second molars, with compound Class II lesions.
  • The selected teeth should be in occlusion with natural dentition and having proximal contact with adjacent teeth.
  • Healthy periodontium.

Exclusion Criteria:

• Exclusion criteria for patients

  • Poor oral hygiene.
  • Patients with high caries index or high plaque index.
  • Patients with periodontal problems.
  • Heavy bruxism habit or presence of any parafunctional habits.
  • Any allergic reactions against any components of the materials to be used in the study.
  • History of severe medical complications such as xerostomia.
  • Pregnant or lactating women.
  • Participating in another clinical trial.

• Exclusion criteria for teeth

  • Fractured or evidently cracked teeth.
  • Defective restorations adjacent or opposite the selected tooth for research.
  • Atypical extrinsic staining of teeth.
  • Teeth with defects or lesions requiring other operative interventions.
  • Teeth with pulpal pain.
  • Teeth with periapical lesions.
  • Root Canal treated teeth.
  • Mobile Teeth.
  • Non-functioning teeth with no opposing tooth.
  • Signs of severe attrition.
  • Heavy occlusion.
  • Periodontally affected teeth.