Oral Health Related Quality of Life and Cost Effectiveness in CAD/CAM and Conventional Metallic Partial Denture Frameworks in Mandibular Kennedy Class III Cases: A Randomised Cross-over Trial

Eligible patient will be selected from outpatient clinic in removable prosthodontics department clinic. Patients will be informed of the nature of the research work and informed consent will be obtained from each of them. Only motivated patients who shows cooperation will participate in the study. Patients will be randomised to receive CAD/CAM metallic RPD followed by Conventional metallic RPD (Group A), or the opposite sequence (Group B), with a 3-month wear duration for each denture and washout period for one week. Patients will be recalled at base line and 3 months following prosthetic insertion to evaluate Oral health related quality of life and cost effectiveness.

Patients will be subjected to:

• Comprehensive clinical examination and understanding of patient's chief complaints and their expectations from the prosthesis.
• Digital periapical radiographs with paralleling technique will be taken for the abutment teeth as base line for bone height before prosthesis construction.

CAD/CAM metallic RPD:

1. Make digital scans using an intraoral scanning device. Scan the maxillary (antagonistic scan) and mandibular (pre-preparation scan) arches, as well as an initial digital record of the inter-occlusal relation (occlusal scan).
2. Analyse the digital cast using CAD software. Primary electronic surveying will be carried out to ensure if the tooth preparations will be needed.
3. Make a definitive intraoral scan only of the prepared teeth and record the maxillary-mandibular relationship.
4. The virtual cast is digitally surveyed and the design of the framework is done using computer software. The wax pattern 3D framework information will be converted into a standard tessellation language (STL) file and transfer to a rapid prototyping (RP) system to be printed and finally cast using the conventional technique to produce RPD framework.
5. The overall treatments costs, including the fees from the dental laboratory, will be calculated and compared with the costs of a conventionally fabricated RPD.