The aim of the study is to compare the effect of high intensity light cure (2200 mw/cm2) for 1 second with low intensity light cure (1200 mw/cm2) for 20 seconds on the clinical performance of bulk fill resin composite restorations in compound Class II cavities of posterior teeth

The prepared cavities will be conditioned with 35% phosphoric acid gel for15 seconds, then will be rinsed and dried with compressed air. Then application of universal adhesive system to all cavity with bond brush then light cured for 10 seconds using LED light curing unit (1200 mw/cm2). Extra-Fill bulk fill resin composite will be applied in onebulk increment and will be light polymerized for 1 second using (LED) light curing unit (2200 mw/cm2).for intervention group Extra-Fill bulk fill resin composite will be applied in one bulk increment and will be light polymerized for 20 seconds using (LED) light curing unit (1200 mw/cm2) fot control group

Inclusion Criteria:

• Permanent premolars or molars.
• Moderate to deep compound class II cavities.
• Vital with the positive reaction to a cold thermal stimulus.
• Absence of parafunctional habits

Exclusion Criteria:

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

The aim of the study is to compare the effect of high intensity light cure (2200 mw/cm2) for 1 second with low intensity light cure (1200 mw/cm2) for 20 seconds on the clinical performance of bulk fill resin composite restorations incompound Class II cavities of posterior teeth

T0: baseline (after one week) T1: after 6 months T2: after 12 months

1. Permanent premolars or molars.
2. Moderate to deep compound class II cavities.