In patients with compound posterior proximal cavities, will the use of organically modified ceramic resin composite restorative material have similar clinical performance to conventional bulk fill resin composite, evaluation of restorations will be done at baseline,six and twelve months using World Dental Federation FDI criteria.

The study will be conducted in the clinic of Conservative Dentistry Department, Faculty of Dentistry, Cairo University; the operator in charge Safinaz Hussien ,The subjects fulfilling the eligibility criteria of the trial will be selected from the regular attendees at the clinic of Conservative Dentistry Department, Faculty of Dentistry, Cairo University.Patient examination will be done including medical history, dental history, extra-oral examination and intra-oral examination. A periapical radiograph will be taken prior to restorative procedures to assess the degree of approximation of caries to pulp, intactness of lamina dura and/or presence of any periapical radiolucency to exclude the case.The field of operation will be isolated with the application of a rubber dam if possible. Otherwise, cotton rolls and the saliva ejector will be used for moisture control. For cavity preparation, local anesthetic (Mepecaine-L, Alexandria Company, Egypt) solution will be administrated to control patient discomfort during the procedure.The cavities will be prepared by using cylindrical #314 (Komet®, Germany) in a high speed handpiece (Sirona, Germany) rotating at high speed with copious coolant. Remaining soft caries -if present- will be removed using sharp excavator (Maillefer, Dentsuply, Switzerland).After the cavity preparation is finished, it will be thoroughly air-water cleaned. The bonding system; FuturabondU(Voco, Germany) will be applied according to the following instructions recommended by the manufacturer: Futurabond M+ will be applied to prepared tooth structure and cured for 20 seconds using Elipar™ S10 LED curing light (3M ESPE, St Paul, MN, USA) with light intensity of 1200 mW/cm2. The prepared cavities will be restored with Admira fusion X--tra® bulk (VOCO, Cuxhaven in layers that are a maximum of 4 mm thick then cured for 20 seconds using usingElipar™ S10 LED curing light (3M ESPE, St Paul, MN, USA) with light intensity of 1200 mW/cm2. and for the control group cavities will be restored with GrandioSO x-tra(VOCO, Cuxhaven) in layers that are a maximum of 4 mm thick then cured for 20 seconds using usingElipar™ S10 LED curing light (3M ESPE, St Paul, MN, USA) with light intensity of 1200 mW/cm2.

Inclusion Criteria:

• Patients aging ≥18 years.
• Patients with a high level of oral hygiene.
• Patients having at least 1or 2 posterior teeth in occlusion.
• Patients with good likelihood of recall availability.

Tooth inclusion:

• Permanent premolars or molars.
• Moderate to deep compound class II cavities.
• Primary carious lesions.
• Vital with positive reaction to cold thermal stimulus.
• Well-formed and fully-erupted in normal functional occlusion with natural antagonist and adjacent teeth.

Exclusion Criteria:

• Participants with general/systemic illness.
• Pregnant or lactating females.
• Concomitant participation in another research study.
• Inability to comply with study procedures.
• Heavy bruxism habits.
• Last experience with allergic reactions against any components of the used materials.
• Patients receiving orthodontic treatment.

Tooth exclusion:

• Teeth with clinical symptoms of pulpitis such as spontaneous pain or sensitivity to pressure.
• Non-vital teeth.
• Secondary carious lesions.

expecting to have all the data by October 2022