Objective: To evaluate and compare the effect of two different attachment housing materials-Acetal Resin (Polyoxymethylene) versus conventional Nylon elastic caps-on marginal crestal bone loss around dental implants supporting a mandibular overdenture. It also evaluates peri-implant clinical tissue health by measuring pocket depth and the gingival bleeding index.

Study Design & Timeline: A prospective, double-blind, randomized controlled clinical trial with a 1:1 allocation ratio. Clinical and radiographic outcomes will be evaluated at overdenture insertion (baseline), and at 6 and 12 months post-insertion.ethodology & Analysis: Pre-operative bone volume will be assessed via Cone Beam CT (CBCT). Crestal bone loss will be measured using the long cone parallel radiographic technique , while pocket depth and gingival bleeding will be measured using a William's graduated probing device. Data will undergo normality testing to determine the use of parametric (Independent t-test, Repeated Measures ANOVA) or non-parametric (Mann-Whitney, Friedman) statistical analyse

Inclusion Criteria:

• Completely edentulous mandible.
• Sufficient bone height/width in mandibular residual ridges.
• Angles classification class I.
• Sufficient inter-arch distance

Exclusion Criteria:

• TMJ disorders.
• Diabetic
• Hypertensive
• Cancer patients.
• Smoker
• Osteoporosis.
• Immunosuppressive disease
• Any disease affecting bone/implant stability.

to avoid hormonal imbalance

1. Chronological Timeline and FrameworkTrial Duration: The active comparative clinical trial is designed to span a duration of one year. Measurement Intervals: Data collection and patient evaluation are scheduled at three distinct time points: at overdenture insertion (baseline), at 6 months, and at 12 months post-insertion