Accuracy of 3-dimensional Printed Implant Cast Versus Conventional Stone Cast for Edentulous Mandibular Arch

Inclusion Criteria: * • Patients were healthy and free from all systemic diseases that affect osseointegration or bone resorption around the implant as recorded from medical and dental history. * Patients were free from all oral pathological conditions and any remaining roots which were verified by pre-operative panoramic radiograph. * Patients with U shaped arch, flat mandibular alveolar ridge covered with even compressibility healthy mucosa and gingival thickness of about 2mm verified by dual scan of cone beam computed tomography (CBCT) during treatment planning. Fig.(1) * Adequate residual alveolar bone quality D2 bone type in the anterior and premolar regions according to the Misch bone density classification scheme (850 to1250 housefield units) confirmed by CBCT. * Angel's class I maxillomandibular relation with moderate inter- arch space (20 mm) confirmed through tentative jaw relationship, and restorative space of at least 15 mm determined by putty index technique * Patients complain from poor retentive mandibular denture seeking for alternative fixed options. * Patient who is motivated, agreed with the follow-up visits and willing to return for follow-up appointments. Exclusion Criteria: * • Patient with absolute contraindications that interfere with surgical placement and osseointegration of implants as uncontrolled diabetes mellitus, generalized osteoporosis, recent myocardial infarction, patient with radiotherapy. * Patient with relative contraindication such as UN controlled diabetes mellitus, moderate smoking and alcoholism, patient with TMJ disorder and heavy smokers for more than10 cigarettes per day. * Patient with local contra indication as insufficient bone quality, localized lesion in canine area and premolar area, unfavourable position of the lower alveolar or mental nerve, bone defects as verified by cone beam CT. * Uncooperative patient.