Mostafa Hossam; Waleed Elshahawy And Gaber E. Masoud,

ABSTRACT

Objectives: The Purpose Of This In-vitro Study Is To Evaluate The Marginal Adaptation And Fracture Resistance Of The High-Performance Polymer (Bio HPP) Three-unit Fixed Dental Prostheses (FDPs) Framework And Compare It With That Of Yttrium-oxide Partially Stabilized Zirconia (Y-TZP). Methods: Two Groups Of Standardized Three-unit FDPs Framework With Flat Occlusal Surface (n=10/group) Were Fabricated. The First Group (control) Was Made Of Zirconia Blank. The Second Group Was Made Of Bio HPP Blank Using (CAD/CAM) Milling Machine. The Wall Thickness Of The Framework Was 0.7 Mm And The Connectors Had An Almost Rectangular Cross-section Of 7.36 Mm2 Surface Area, An Occluso-gingival Height Of 3.2 Mm, And A Bucco-lingual Width Of 2.3 Mm. To Evaluate The Marginal Adaptation, Each Specimen Was Photographed Before And After Cementation Using USB Digital Microscope With A Built-in Camera Connected With An IBM Compatible Personal Computer Using A Fixed Magnification Of 50 X, A Digital Image Analysis System Was Used To Measure And Evaluate The Vertical Gap Length. To Evaluate The Fracture Resistance, All Samples Were Individually Mounted On The Universal Materials Testing Machine, Fracture Test Was Done By Compressive Static Load Applied Occlousally At The Center Of The Pontic With Upper Movable Compartment Of A Universal Testing Machine Traveling At Cross-head Speed Of 1mm/min. The Load Required To Fracture Was Recorded In Newton.

Results: It Was Found That Zirconia Group Recorded Statistically Non-significant Higher Marginal Gap Mean Value (22.71�3.1�m) Than Bio HPP Group (20.27�3.03�m) As Indicated By Three-way ANOVA Followed By Pair-wise Tukey?s Post-hoc Tests (P=0.0825>0.05) It Was Noted That Bio HPP Group Recorded Statistically Significant (p<0.05) Higher Fracture Resistance Mean Value (1626.31�191.9 N) Than Zirconia Group (1243.51�175.8 N) As Indicated By Student T-test (t= 3.1, P= 0.007<0.05)

Conclusions: Bio HPP FDPs Framework Showed Non-significant Better Marginal Adaptation Than Zirconia. Bio HPP Framework Showed Significant Higher Fracture Resistance Than Y-TZP Zirconia. It Can Be Potentially Used As Crown And Bridge Material Even In Posterior Area.