Background: Retrieval of cement-retained implant-supported restorations is intriguing in cases of screw loosening. Detecting the estimated size of the screw access hole (SAH) could decrease destruction to the prosthesis and preserve the crown. Objectives: To precisely localize loose implant screws through cemented crowns to reduce crown damage after screw loosening. Materials and methods: In this in vitro study, 60 cement-retained implants supported 30 zirconia-based, and 30 ceramics fused to metal (CFM) lower molar crowns were invented, and each was subdivided into three subgroups (10 each). In group I (AI/BI) (control), SAH was created with the aid of orthopantomography (OPG). In contrast, in group II (zirconia-crown), SAH was created with the aid of CBCT + 3D printed surgical guide with a 2 mm metal sleeve in subgroups IIA/IIIA and CBCT + MAR was used to develop SAH in subgroups IIB/IIIB. SEM and Micro-CT scanned the SAH openings to determine the diameter of the hole, cracking, chipping, and chipping volume. Results: Regarding the effect of plane CBCT and CBCT + MAR on prepared crowns, a highly significant association between group I with group II (p = 0.001) and group III (p = 0.002) was detected. Regarding the cracking of SAH, significant differences between the zirconium crown and CFM restoration (p = 0.009) were found, while for the chipping, no significant association was seen between groups (p = 0.19). Conclusions: CBCT, either as a plane CBCT or with MAR, significantly improved the accuracy of drilling the screw channel and decreased injury to the existing restoration and abutment, aiding in better localization of SAH in loosened implant abutment screws.

Objective: Patient perception increasingly influences the selection of restorative dental materials, especially as aesthetic expectations grow within modern dental practice. This study aimed to evaluate patient awareness, attitudes, and preferences regarding amalgam and tooth-coloured restorative materials in Sulaimaniyah City. Methods: A descriptive cross-sectional survey was conducted using a structured questionnaire distributed to patients attending various dental clinics. The questionnaire obtained demographic information, previous restorative experiences, aesthetic expectations, and perceptions of the functional, aesthetic, and biological characteristics of amalgam and composite resin materials. Results: The results showed that most participants preferred tooth-coloured restorations due to their natural appearance and higher aesthetic compatibility. Amalgam was favoured by a smaller proportion of respondents who emphasized its durability, strength, and relative affordability. Younger patients and those with higher educational levels demonstrated stronger preference for aesthetic materials, while awareness of possible health concerns associated with amalgam varied considerably among participants. Conclusions: Overall, the findings reflect a noticeable shift toward aesthetic-driven choices in restorative dentistry within the region. The study concludes that dental practitioners should acknowledge patient preferences during treatment planning and provide balanced, evidence-based information about the advantages and limitations of available restorative materials to support informed decision-making and enhance patient satisfaction.

Background: The restorative material used to seal the screw access channel in screw-retained implant-supported crowns may influence the biomechanical behavior and mechanical performance of the restoration. Objective: To evaluate the influence of different screw access channel restorative materials on stress distribution and deformation in porcelain-fused-to-metal (PFM) and monolithic zirconia implant-supported crowns using three-dimensional finite element analysis (FEA). Materials and Methods: Three-dimensional finite element models of screw-retained PFM and monolithic zirconia implant-supported crowns were developed. Four restorative materials—direct composite resin, resin matrix ceramic (RMC), lithium disilicate (LDS), and zirconia inlays—were used to restore the screw access channel. Each model was subjected to 200 N vertical and oblique occlusal loads. Equivalent von Mises (EVM) stress and total deformation were calculated and compared among the different restorative materials and crown types. Results: In PFM crowns, lithium disilicate and zirconia inlays produced lower stress transfer under vertical loading than direct composite resin and resin matrix ceramic. Under oblique loading, the differences in stress distribution among restorative materials were less pronounced. Zirconia inlays exhibited the highest internal stress concentrations but the lowest deformation, whereas direct composite resin demonstrated the greatest deformation. In monolithic zirconia crowns, deformation values were comparable among zirconia, lithium disilicate, and resin matrix ceramic inlays, indicating that the high stiffness of the zirconia crown largely governed the biomechanical response. Conclusions: Both the crown material and the restorative material used to seal the screw access channel affected the biomechanical performance of implant-supported restorations. Lithium disilicate and zirconia demonstrated more favorable mechanical behavior than direct composite resin, which exhibited greater deformation. These findings suggest that indirect restorative materials may provide biomechanical advantages over direct composite resin, particularly in restorations subjected to higher occlusal loads.