Computer-aided designs have considered dynamic occlusion with virtual articulator systems. However, the process involved is currently lengthy. The simplified transfer of casts from a mechanical to a virtual articulator has required bulky and expensive instruments. Recently, new methods based on mandibular motion tracking using optical devices have been introduced for integrating individual functional movement into occlusal morphology.

The aim of this study: This study will clinically assess the reliability of the virtual reproduction of mandibular movement for detecting occlusal interferences and adjustments of designed and milled CAD-CAM zirconia crowns using a digital occlusal analyzer.

Materials and methods: Intraoral optical impression will be made for thirteen selected patients with endodontically treated maxillary first premolars after abutment preparation followed by buccal and lateral interocclusal records taking. Two zirconia crowns will be fabricated for each patient following regular digital workflow with twenty six zirconia crowns, which will be allocated according to the virtual method of adjustment of occlusal interferences into two groups (Group I: Virtual occlusal interferences adjustment of CAD-CAM zirconia crowns using buccal interocclusal record (n=13) and Group II: Virtual occlusal interferences adjustment of CAD-CAM zirconia crowns using buccal and lateral interocclusal records (n=13)). Then milling and sintering of all crowns will be performed following the manufacturer's instructions. The occlusion of all crowns will be analyzed using an electronic pressure analyzer. All data will be statistically analyzed and discussed in light of the results obtained.

Inclusion Criteria:

The patient presented with successful endodontically treated maxillary 1st premolar.

• Patients having class I occlusion.
• Good oral hygiene with no signs of periapical pathology or periodontal disease(24).
• Patient having natural teeth as opposed to dentition.

Exclusion Criteria:

• Pregnancy, which prevents the use of diagnostic x-rays.
• Parafunctional habits.
• Mobility in the abutment teeth more than grade 1.
• Patient presenting allergy to materials being used.