Management of a Fractured Multiunit Maxillary Implant-Supported Fixed Prosthesis with Stripped Abutment Screws Using a Hybrid Cement-Retained and Screw-Retained Design: A 5-Year Follow-Up Clinical Report Mohammad D. Al Amri, BDS, MS, FRCDC Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia The article is associated with the American College of Prosthodontists’ journal-based continuing education program. It is accompanied by an online continuing education activity worth 1 credit. Please visit www.wileyhealthlearning.com/jopr to complete the activity and earn credit. Keywords Implant-supported prosthesis; cement-retained; screw-retained; loosening, fracture, retrievability. Correspondence Mohammad D. Al Amri, Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, P. O. Box 60169, Riyadh 11545, Saudi Arabia. E-mail: dramri@yahoo.com The author denies any conflicts of interest. Accepted September 14, 2015 doi: 10.1111/jopr.12433 Abstract Fracture and loosening of implant-supported prostheses (ISPs) are complications encountered in routine dental practice. In the present report, management of a fractured maxillary full-arch cement-retained (CR) fixed dental prosthesis supported by six implants is presented. Due to stripped screws, complications were encountered that prevented the retrieval of two of the six abutment screws, which was managed by using a hybrid retention approach, whereby a single full-arch CR and screw-retained (SR) ISP was used. The techniques used to successfully retrieve four of the abutment screws are described. The final retention design involved a combination of three CR and three SR restorations, which offers the advantages of both retention designs. Conventionally, implant-supported prostheses (ISPs) are ex- clusively screw-retained (SR), particularly in fully edentulous patients. 1 However, cement-retained (CR) prostheses have be- come a popular treatment option, mainly in treatments with single and fixed partial prostheses. 2,3 Previous studies 4-6 have reported that the main disadvantage of CR ISPs is the lack of reliable retrievability compared with SR ISPs; however, com- pared with SR prostheses, CR prostheses may offer other clini- cal advantages, such as greater passivity of fit, fewer incidences of ceramic veneer fracture, improved esthetics, reduced cost and complexity of laboratory procedures, and ability to create a more precise occlusion and to compensate for malpositioned implants. 4-13 Furthermore, microstrain and stress distribution between multiple splinted implant restorations is less favorable in SR prostheses, as it can lead to a higher risk of screw loosen- ing and fracture. 2,14-16 However, according to Karl et al, 17 the retention mechanism appears to have a minor effect on strain development in ISPs. In the present 5-year follow-up clinical report, management of a fractured multiunit maxillary implant-supported cement- retained fixed prosthesis using a hybrid retention design of CR and SR crowns is described. The clinical management of this case included the successful use of novel techniques to retrieve four of the six stripped abutment screws. Clinical report A 67-year-old male patient was referred from the Clinic of Pe- riodontics at the College of Dentistry of King Saud University in Riyadh, Saudi Arabia to the prosthodontic clinic at the same college for final restoration of the implants placed in the areas of missing teeth (Table 1). The patient self-reported as a non- smoker and had a medical history of type 2 diabetes mellitus (DM). After a comprehensive clinical examination and inves- tigation, the treatment options and plan were discussed with the patient. From the time of implant placement until the final restoration, the patient did not wear an interim prosthesis. The patient’s plaque score and bleeding index were 45% and 35%, respectively. In addition, the fasting blood glucose level of the patient was 77 mg/dl. A full-arch fixed ISP was fabricated and cemented onto the six maxillary implants using provisional cement (Temp Bond NE; Kerr Corporation, Orange, CA). Likewise, the mandibu- lar implants were restored using splinted cemented restorations (Fig 1). Occlusion was restored in a mutually protected ar- ticulation with stable bilateral centric contacts; however, the patient returned to the clinic four times within 6 months after the FPD placement with complaints of loosening of the maxil- lary prosthesis. During the first three return visits, the prosthesis 330 Journal of Prosthodontics 25 (2016) 330–334 C  2015 by the American College of Prosthodontists