Aim: This clinical study was conducted to evaluate the effect of using different denture base material on masticatory efficiency in implant supported complete mandibular overdenture. Subjects and methods: Twelve completely edentulous patients were selected for this study according to inclusion and exclusion criteria that affect implant success or masticatory system. History taking, clinical, and radiographic evaluation were done for each patient. Preoperative cone beam computerized tomography (CBCT) was done for each to determine bone height and width. Each patient received two implants in the inter-foraminal area of mandible, three months later lower denture was converted into mandibular overdenture. Patients were grouped in two groups Group I: patients were received a complete mandibular overdenture constructed of conventional heat cured acrylic resin denture base. Group II: patients were received a complete mandibular overdenture constructed of flexible denture base material (polyamide). Evaluation of masticatory efficiency were done for each group by calculating chewing numbers and times. All evaluations were done at the time of implant placement, three months, six months, twelve, eighteen and twenty-four months of implant placement. One-way ANOVA with post hoc turkey test was used for multiple time comparison. Results: The chewing number and times was non-significant between the two groups. Conclusion: The denture base has no effect on masticatory efficiency of mandibular implant supported overdentures.

Aim of this study was to evaluate influence of thermoplastic denture base material on plaque index and depth of gingival sulcus of implants supported mandibular overdenture. Patients and methods: Twenty completely edentulous patients were selected according to inclusion and exclusion criteria that affect implant success. Two implants were implanted in the interforaminal area of mandible following the two stages surgical protocol; patients were grouped into two groups Group I (TPG) patients received a complete mandibular overdenture constructed of thermoplastic poly amide denture base material and Group II (HCG) patients received a complete mandibular overdenture constructed of conventional heat cured acrylic resin, both groups are retained by ball and socket attachment system. Plaque index and depth of gingival sulcus were measured for each group after overdenture construction and every three months interval for 24 months. One-way ANOVA with post hoc turkey test was used for multiple time comparison. Results: the mean value of pocket depth between 2 groups [TPG -HCG] at different period has no statistically significant difference but statistically significant at a period of twenty four month <0.001 * P-value. plaque index show statistically significant <0.001 * P-value at all different periods. Conclusion: thermoplastic denture base overdenture has a superior benefit than conventional heat cured type as it give longevity of supported implant by enhancing peri-implant gingival health with reduced pocket depth and plaque index.

An in-vitro experimental study was conducted to compare retention and deformity of three different RPD clasp materials (poly ether ether ketone, nickle titanium alloy, and acetal materials) with conventional cobalt chromium alloy; material and methods; A total of (56) RPD's Aker clasps were divided into four equal main groups (n=14) according to type of clasp materials; poly ether ether ketone (PEEK), nickle titanium (Ni/Ti), acetal, and cobalt chromium (Co/Cr) materials. All clasp samples in each group were used for retention test and deformity test.Results: One way ANOVA test and Pairwise comparison between each 2 groups using Post Hoc Test were used for retention and deformity tests at base line and after 730 , 1460 ,2190 and 2920 cycles revealed that metallic (Co/Cr) clasps ofer greater retentive forces followed by(Ni/ Ti) than non metallic (PEEK) then acetal resin clasps with differences considered as Statistically significant as p ≤ 0.05 at all testing loading cycles. also (Co/Cr) clasps offer greater deformity value followed by(Ni/Ti) than non metallic (PEEK) and acetal resin clasps with differences considered as Statistically significant as p ≤ 0.05 nearly at all testing loading cycles except at 2920 cycles where non-metallic (PEEK) followed by acetal resin clasps offer greater deformity than metallic(Co/Cr) clasps then(Ni/Ti) with differences considered as Statistically significant as p ≤ 0.05.Conclusion within limitations of this study it is better to use PEEK clasps for esthetic reasons; and (Co/Cr) clasps for retention reasons.