John Nagy Zaki, Amr Fouad Zahran, Ahmed Reda Abe El Rahman And Rania Farouk Mohamed,

ABSTRACT
This Paper Is Based On The Ph.D Thesis Of The First Author And Supervised By The Other Authors. Background: In Horizontal Ridge Augmentation Procedures The Clinicians Should Achieve A Passive Flap Closure Through Flap Release Techniques ?mostly Periosteal Releasing Incisions. However, Coronal Advancement Of The Tissues Might Place The Thin, Non-keratinized Tissues At Or Near The Crest Of The Ridge That Later On Might Have A Deleterious Effect On The Esthetics And Function Of The Implant-based Prosthesis.
Objectives: To Test The Efficacy Of The Xenogeneic Collagen Matrix In Increasing The Thickness Of The Peri-implant Soft Tissue And Widening The Zone Of Keratinized Tissue, When Used In Conjunction With Crest-split Technique And Simultaneous Implant Placement.

Materials and Methods: This Study Involved 20 Candidates For Horizontal Ridge Augmentation With Split-crest Technique And Simultaneous Implant Placement In The Anterior Maxilla. The Participants Were Randomized And Allocated To 2 Equal Groups. Group (A) Was The Test Group And Its Members Received The Xenogeneic Collagen Matrix In Addition To The Augmentation Procedure, While Group (B) Was The Control Group And Its Members Received Only The Augmentation Procedure. The Primary Outcome Was The Soft Tissue Thickness Measured By An Endodontic File And Ruler At Baseline, 3 And 6-months Post-operatively. The Secondary Outcome Was The Width Of Keratinized Tissue Measured By A Periodontal Probe At Baseline, 2, 3 And 6-months Post-operatively.

Results: The Mean Age (years) Was 37.1 � 12.3 For Group (A) And 38.0 � 12.3 For Group (B) With 7:3 Female To Male Ratio In Each Group. For The Soft Tissue Thickness There Was A Statistical Significant Increase (r=0.476, 95% CI=-0.22?0.85, P= 0.034) At 3-months In Group (A) Compared With Group (B) In The Overall Soft Tissue Thickness. However There Was No Difference At 6-months Follow-up (d= 1.012, 95% CI= (0.081?1.943), P= 0.034). The Outcome Width Of Keratinized Tissue Didn?t Express Any Significant Difference At 1 (p=0.183), 3 (p=0.166) Or 6-months (p=0.201) Follow-up. Conclusion: Split-crest Technique With Simultaneous Implant Placement Is A Successful And Predictable Technique Following Proper Case Selection. However, Xenogeneic Collagen Matrix (XCM) Lacks The Volume Stability To Augment The Soft Tissue Thickness, Also XCM Has A Modest Effect On Increasing The Width Of Keratinized Tissue When Used As An Inter-positional Graft.