All teeth will be treated with (Palodent ® plus sectional matrix system) (sectional matrix, biting ring, plastic diamond wedge)

Proximal contact tightness (PCT) will be measured using the custom-made contact pressure system that was based on the tooth pressure meter, a device fabricated at the University of Technology, Delft, the Netherlands. (20) The system will use a 0.05-mm-thick metal strip inserted interdentally from An occlusal direction . The metal strip will be connected to the digital force gauge (Mark-10 series 2 digital force gauge). The tightness of the proximal contact will be quantified as the maximum frictional force when the strip will slowly removed in a buccal-lingual direction. The maximum force will be recorded on the screen of the gauge for each measurement when the gauge will be switched to peak-mode

calibration will be carried out by a radiologist, who evaluates the teeth carefully scrolling down through the images from the floor of the pulp chamber in all three orthogonal reconstructions (axial, coronal, and sagittal). To ensure image standardization, all cone-beam computed tomography (CBCT) images will be chosen from a single machine with a standard field of view, voxel size, exposure time and the thickness of the slice.

CBCT images will be analyzed with the built-in digital imaging software. The measurement tool will be used to determine the total length of the crown of the restored teeth, measured from the tip of the mesiobuccal cusp to the cementoenamel junction. Based on this length, the crown portion will be divided into three levels: coronal, middle and apical thirds.