الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The advancement in Computer-aided design and computer-aided manufacturing (CAD-CAM) technology has postulated many applications in dentistry, especially implant prosthodontics. Dental CAD-CAM systems are now able to produce custom dental implant abutments, however, there is a paucity of information regarding the accuracy of the mating surfaces and biological performance during clinical service.
This study was conducted to custom titanium dental implant abutments evaluate in two categories; in vitro part that evaluated surface roughness and interfacial micogaps, and clinical trial to evaluate biological, clinical, and radiographical parameters. To characterize the manufacturing of custom implant abutments, in vitro laboratory evaluation was done to assess surface roughness (Ra), and microgap size at the implant-abutment interface. Ten custom abutments were fabricated and compared to 10 stock abutments for Ra evaluation using a confocal laser microscope at the mucosal cuff area. The same abutments were torqued into implant bodies to be evaluated for interfacial microgaps using a stereomicroscope.
For the randomized controlled trial, thirty participants with single missing mandibular first molars underwent implant placement following the standard 2-stage surgical protocol. Second-stage surgery was commenced 3 months after implant placement. All participants were randomly assigned into one of the two groups; Control group (n=15): Pre-machined stock titanium implant abutment, and Test group (n=15): Custom titanium CAD-CAM abutment. All abutments received monolithic complete contour zirconia crowns. Sampling of peri-implant sulcular fluid was done and clinical parameters were assessed at baseline, 3-, 6- and 12- month
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time points. Crestal bone loss was evaluated by comparing radiographs at baseline and 12- month time points. MMP-8 level was assessed by Enzyme-Linked ImmunoSorbent Assay (ELISA).
No significant differences were found between stock and custom abutments regarding surface roughness or microgaps at the implant-abutment interface. MMP-8 levels of both types of abutments were comparable at all time points. All clinical parameters and crestal bone loss recorded no significant differences between the two types of abutments at all time points.
Custom titanium abutments fabricated by dental CAD-CAM system had surface roughness and microgaps at implant-abutment interface comparable to the manufacturer’s stock titanium abutments. Soft tissue around both types of abutments showed a similar reaction in terms of MMP-8 level, clinical parameters, and crestal bone level.