Objective:This clinical study was conducted to evaluate the effect of immediate loading on peri-implant soft tissue health using three protocols: i) Immediate functional loading using polymer infiltrated ceramic (PIC) material (IFLV). ii)Immediate functional loading using polymethyl methacrylate (PMMA) followed by delayed functional loading using PIC material (IFLP). iii) Immediate non-functional loading using PMMA followed by delayed functional loading using PIC material (INFLP). Material & Methods: 30 Implants were placed in the upper premolar area and divided randomly according to the immediate loading protocol. In the control group (INFLP), CAD/CAM PMMA crowns were placed out of occlusion for 3 months, and then replaced by CAD/CAM VITA ENAMIC crowns in functional occlusion. For (IFLV) group, CAD/CAM VITA ENAMIC crowns were immediately loaded in functional occlusion; while in (IFLP) group, CAD/CAM PMMA crowns were placed in functional occlusion for 3 months, and then replaced by CAD/CAM VITA ENAMIC crowns. Modified pink esthetic score (MPES) and probing depth were used for evaluation of peri-implant soft tissue at base line and follow up periods. Results: INFLP showed higher MPES results compared to IFLV and IFLP. Moreover, the INFLP probing depth at 3 months showed higher results compared to the other groups. Conclusions: Immediate non-functional loading showed the best outcomes. However, peri-implant soft tissue health of the immediate functional loading using the PIC crown material was clinically acceptable.Key WordsPolymer infiltrated ceramics, immediate dental implant loading, peri-implant soft tissue health.

Background This study aimed to evaluate and compare the marginal gap using two different methods and the internal fit of 3D printed and zirconia crowns. Methods 3Y-TZP zirconia crowns (n = 20) were manufactured using subtractive milling (group M) and 3D printed (group P). The marginal gap was measured at 60 points using vertical marginal gap technique (VMGT). On the other hand, the silicone replica technique (SRT) was used to evaluate the internal fit and was divided into 4 groups: marginal gap, cervical gap, axial gap, and occlusal gap where the thickness of light impression was measured at 16 references. The numerical data was tested for normality using Shapiro–Wilk's test. They were found to be normally distributed and were analyzed using an independent t-test. Results Using VMGT, group P had significantly higher mean marginal gap values of 80 ± 30 µm compared to group M = 60 ± 20 µm (p < 0.001). Also, with the SRT, the marginal gap of group P (100 ± 10 µm) had significantly higher values compared to group M (60 ± 10 µm). The internal fit showed significant difference between the tested groups except for Axial Gap. Conclusions Although milled crowns showed better results. The 3D printed zirconia crowns offer clinically acceptable results in terms of marginal adaptation and internal fit. Both VMGT and SRT are reliable methods for the assessment of the marginal gap.