Aging, Antioxidants, Skeletal muscle.During aging, skeletal muscle is subjected to progressive loss of muscle mass and strength (sarcopenia) and a decline in the functional ability. The reduction in the antioxidative capacity of the skeletal muscle resulting in an abnormal accumulation of the reactive oxygen species (ROS) that is one of the possible causes of the decline in muscle performance. In this study the histological changes in the soleus muscles of male mice at the age of 1 st and 15 th old were examined and the activities of the antioxidant enzymes, CAT and SOD, non-enzymatic antioxidant GPH and MDA level were measured to clarify the age-related changes in healthy subjects. Results showed that there is a significant reduction (P ≤ 0.05) in the antioxidants SOD, CAT and GPH and there is a significant increase (P ≤ 0.05) in MDA level at the age of 15 th month when compared to 1 st month old. We concluded that the activities of the antioxidants were affected by aging. Moreover, there is age-related lipid peroxidation.

Statement of problem:Longer-term clinical trials with success data are required to validate the current design options of Ti base as viable abutments.Objective: The aim of this clinical research was to investigate the influence of abutment designs on the clinical outcome of screw-and cement-retained, implant-supported monolithic zirconia crowns. Material and methods:A total of 28 patients with missing 30 single maxillary premolar areas were implanted (4.1x12mm), and random classified into 3 equal groups (n =10): Group (A) (VC): patients receiving hybrid Ti base abutments (Variobase, Straumann, Switzerland) with cementretained crowns, Group (B) (VS): patients receiving hybrid Ti base abutments (Variobase) with screw-retained crowns, Group (C) (DS): patients receiving non-segmented screw-retained crown (cemented onto Dess Ti Base). The monolithic zirconia crowns were CAD/CAM fabricated, cemented, and evaluated at baseline, 3, 6, 12 and 18 months clinically and radiographically. All data were collected and statistically analyzed.Results: All 30 implants remained stable and reached osseointegration (100% cumulative success rate ⁅CSR⁆). The highest mean average crestal bone level (BL) measured 1.23+0.72mm (median: 1.40mm, range: 0.00-2.25mm) (P=0.09 NS) in group (C) (DS), and the least mean BL measured 1.00+0.55mm (median: 1.10mm, range: 0.00-2.00mm) and (median: 1.00mm, range: 0.10-1.90mm) (P=0.83 NS) and (P=0.52 NS) in the groups (B and A) (VS and VC) respectively. Conclusions:Under the conditions of this study, using a prefabricated (Variobase or Dess) Ti base as an abutment for an implant-supported zirconia crown is an alternative procedure for FPDs. It promotes healthy and stable hard and soft tissues.