Samia Mostafa Kamal, Rehab A. Abdel Moneim And Aml Mostafa Kamal,

ABSTRACT
Background: Human Eruption Is A Unique Developmental Process In The Organism. The Etiology Or The Mechanism Behind Eruption Has Never Been Fully Understood. Accordingly, The Mechanism Of Eruption Depends On The Correlation Between Space In The Eruption Course Created By The Crown Follicle, Eruption Pressure Triggered By Innervation In The Apical Root Membrane And The Ability Of The Periodontal Ligament To Adapt To Eruptive Movements.

Aim: This Study Was Designed To Localize And Delineate The Role Of The Signaling Molecule; Transforming Growth Factor Beta (TGF-?) Before, During And After Eruption.

Materials and Methods: The Study Was Carried Out On Twenty Adult Albino Rats (6-8 Months Old) And Of Average Weight 200-250 Gm. The Rats Were Housed Together For Mating. After Pregnancy Confirmation, The Off- Springs Were: Sacrificed At Birth (Group I), 5 Days Postpartum (Group II), 10 Days Postpartum (Group III) And 15 Days Postpartum (Group IV). Each Group Consisted Of Ten Off-springs. The Lower Jaws Of All Off-springs Were Then Dissected, Processed And Mounted In Paraffin Wax For Histological Examination, Immunohistochemical Assessment And Statistical Analysis.

Results: Immunohistochemical Investigation Showed That TGF-? Was Widely And Deeply Expressed In Tooth Follicle And Bone Trabeculae At The Base Of The Growing Tooth At All Developmental Ages And Was Significantly Increased At 15 Days Postpartum With Statistical Significance; P<0.0001. Conclusion: Although The Exact Mechanisms Of Eruption Are Not Yet Known, We Proposed A Close Relation Between Signaling Molecules And Eruption Process Based Upon Our Findings And The Apparent Effects Of TGF-? On Odontogenesis And On The Whole Eruption Process.

Nermeen Ahmed Hassan , Amr Hosni El-Khadem And Maha Wagdy El-Kerdawy,

ABSTRACT
Background: Titanium Has Been Used Considered The Gold Standard For Dental Implants For Many Years Due To Its Superior Mechanical Properties. However, It Has Many Drawbacks Regarding Corrosion And Esthetics That Required Searching For Another Alternative. In This Study, We Aimed To Determine The Amount Of Stresses Developing In The Peri-implant Bone Under Vertical Load When Different Types Of PEEK Are Used As An Implant Material.

Materials and Methods: Four Virtual Models Of A Mandible With Two Inter-foraminal Implants Supporting An Overdenture Were Designed Using SolidWorks Software. Unilateral Vertical Load Was Applied Over The Denture Teeth And Von Misses Stresses Were Collected From The Peri-implant Bone.

Results: Von Mises Stresses In The Coronal Portion Of The Peri-implant Bone Was The Highest Around PEEK Implants And The Least Around Titanium Implants. Conclusion: PEEK Can Be Used As An Alternative To Titanium In Dental Implants From The Mechanical Point Of View, But Further Clinical Studies Are Recommended To Test The Material Behavior Intraorally.

Mennat-Allah Sayed Gaber, Shaymaa I. Habib And Abdel-Hadi Mohamed Amin,

ABSTRACT


Purpose: The Aim Of This Study Was To Evaluate Solubility, Calcium And Phosphorus Ions Release And Bioactivity Of Resin Modified Glass Ionomer Cement Before And After Addition Of Nanobioactive Glass Particles.

Materials and Methods: One Commercially Available Resin Modified Glass Ionomer Cement And Nanobioactive Glass Particles Were Used In This Study. Bioactive Glass Was Added To The Cement Powder By Two Weight Percentages 2wt% And 5wt%. Solubility Was Evaluated Using ANSI/ADA Specification No.66-1989 For Glass Ionomer Cements. Twenty One Samples (n=7/gp) Were Prepared Using Split Teflon Mold (7.75�1.5mm). Solubility Was Recorded At 7 Days And 30 Days. For Calcium And Phosphorus Ions Release, 21 Samples (n=7/gp) Were Prepared Using The Same Mold And Stored In Deionized Water Then Recorded At 7 Days And 30 Days. Regarding Bioactivity ,12 Samples (n=4/gp) Were Prepared And Immersed In PBS Solution For 7 Days And 30 Days And Examined By Scanning Electron Microscope (Field Emission Gun) Attached With Energy Dispersive X-ray Analysis Unit EDXA. The Results Were Statistically Analyzed.

Results: Regarding Solubility, Results Showed A Statistically Significant Difference Between Group I, Group II And Group III After Both 7 Days And 30 Days. Moreover, Storage For 30 Days Showed Statistically Higher Solubility Values In All Groups Than 7 Days. Regarding Calcium Ions Release, There Was A Statistically Significant Difference Between Group I, Group II And Group III After Both 7 Days And 30 Days. However, No Statistically Significant Difference Was Recorded Between 7days And 30 Days In All Groups. For Phosphorus Ions Release, It Was Found That There Was A Statistically Significant Difference Between Group I, Group II And Group III After 7 Days. However, After 30 Days There Was No Statistically Significant Difference Between Group I, Group II And Group III. Results Also Showed Statistically Significant Higher Ph Ions Release After 30 Days Than 7 Days. Regarding Bioactivity, CaP Deposits Were Obvious Only In High Concentrations Of BAG (group III) After 30 Days Immersion In PBS On The Surface Of The Samples With Ca/P Molar Ratio =1.3.

Conclusions: 1. There Is A Direct Relationship Between The Amount Of BAG Added To RMGI And Its Solubility. 2. Although Addition Of BAG To RMGI Increased The Ion Bioavailability And Solubility, The Bioactivity Was Not Sufficiently Improved.

Mohamed S. Elbehairy, Nora Cheta, Tamer M. Nassef And Hamdy A. Hamed,

ABSTRACT
Background Comparing The Effect Of Implant Inclination On Stress Distribution In Peri-implant Bone In Mandibular All On Four Hybrid Prosthesis. Material And Methods Bone Model Was Reconstructed From CBCT Scan Segmentation, Implants And Cad/cam Prosthesis Were Exported As STL Files And Converted Into Solid Parts By Reverse Engineering Followed By Part Assembly, Meshing And Load Application. Results A Large Decrease In Von-mises Stresses Was Observed In The Model With 30 Degrees Tilted Implants. Conclusion Model D30 Was The Best Treatment Design Regarding Stress Distribution Compared To The Other Two Models.

Osama S. Selim, Jihan F. Younis And Tamer A. Hamza,

ABSTRACT
Statement Of Problem: The Mechanical Properties Of Recently Introduced Zirconia Reinforced Lithium Silicate Materials As Full Anatomical Restorations Require More Evaluation. The Lack Of Documentation Studying The Effect Of Different Finish Line Curvatures On The Mechanical Behaviour Of Ceramics Necessitated Investigation. The Purpose Of This In-vitro Study Is To Compare The Fracture Resistance Of Recently Introduced Zirconia Reinforced Lithium Silicate To Lithium Disilicate Using Two Different Finish Line Curvatures.

Materials and Methods: Twenty-eight Crowns Were Milled And Fabricated Using CAD/CAM System On Epoxy Dies Duplicated From A Stainless-steel Master Die. They Were Divided Into 2 Equal Groups (n = 14) According To The Ceramic Material Type Used: Group I, Monolithic Lithium Disilicate (IPS E.maxCAD) And Group S, Monolithic Zirconia-reinforced Lithium Silicate (Vita Suprinity). According To The Finish Line Curvature; Zero And 3mm Curve, Each Group Were Subdivided Into Two Equal Subgroups (n=7). All Specimens Were Cemented On Epoxy Dies Using A Self-adhesive Resin Cement (TOTALCEM, Itena), And Then Loaded Until Fracture Using A Universal Testing Machine. Kruskal-Wallis Test Was Used To Compare Between The Two Ceramic Types. Mann-Whitney U Test Was Used To Compare Between The Two Finish Line Curvatures. The Significance Level Was Set At P ? 0.05. Hypothesis: The Two Different Finish Line Curvatures Will Affect The Fracture Resistance Of The Tested Monolithic Crowns

Results: With Both Ceramic Types, There Was No Statistically Significant Difference Between Mean Fracture Resistance Values Of The Two Finish Line Curvatures. IPS E.maxCAD Showed The Statistically Significantly Higher Mean Fracture Resistance Than Vita Suprinity. Conclusion: The Finish Line Curvature Had No Effect On The Fracture Resistance Of The Tested Ceramic Restorations. The Strength Of Tested Ceramic Is A Material Dependant Where IPS E.maxCAD Crowns Showed Higher Fracture Resistance Mean Values Than Vita Suprinity

Rana Abdel Hameed El Gazar, Mohamad Seddik Mohamad Kamel And Eman Fahmy Ado Elfetoh .,

ABSTRACT
Background: Tooth Bleaching Has Become Popular In Dentistry Since It Has Been Shown To Be An Effective And Noninvasive Treatment. The Bleaching Agent Is Applied In Intimate Contact With The Teeth, With Potentially Associated Restorations, It Has Been Speculated That This Process Could Cause Negative Alterations In Oral Substrates

Purpose: To Evaluate In-office Light-activated Bleaching On Translucency Of Hybrid Ceramic By Measuring Transmittance And Absorption Of Light By Spectrophotometer.

Materials and Methods: Twenty Specimens Were Prepared In (3M2-T) Shade And Were Cut From CAD/CAM Blocks Of Hybrid Ceramic. The Study Will Consist Of Twenty Specimens Of Hybrid Ceramic And These Specimens Will Be Randomly Divided Into 2 Groups. The Translucency Of The Samples Of Group I Act As A Controlled Group Which Were Not Received32% Hydrogen Peroxide Bleaching Agent Was Measured By Spectrophotometer. Samples Of Group II Received 3 Times Applications Of The Bleaching Agent. Each Cycle Ranges 15-20 Min. Then Exposed To A LED Power Bleach System For Three Cycles � 15 Min Each With 10 Min Resting Time. New Translucency Evaluation By The Spectrophotometry In The Same Way For Samples Of Group II.

Results: In This Study, A Comparison Of The Groups Using Independent T-test Revealed Statistically Significant Differences In Translucency Values Before And After Bleaching (P<0.001). After Bleaching, We Can Observe A Decrease In The Absorption Of Light. Also, There Was An Increase In Transmittance Of Light In Group II Samples When Compared With Samples Of Group I. This Is Proved That Bleaching Caused A Highly Significant Change In Translucency Values Of Hybrid Ceramic. Conclusion: In Conclusion, Statistically Significant Differences Among The Translucency Changes Of All Test Groups Were Found After Exposing Them To The Bleaching Agent.

Mohamed Khalid Ebn- Elwaleed Diab, Manal Rafie Hassan And Mohammed Moustafa Shalaby,

ABSTRACT

Objectives: The Aim Of This Study Was To Assess The Effect Of Finishing Techniques On Translucency Of Two All Ceramic Materials (pressed Lithium Di Silicate And Yttrium Stabilized Tetragonal Zirconia). Methods: Sixty Discs Were Fabricated; Thirty Of Each Material Was Divided Randomly To Three Sub Groups According To Techniques Of Traditional Polishing, Auto Glaze And Add-on Glaze. All Of Discs Were Subjected To Aging Procedures Of Thermocycling & Subjected To Different Coloring Solutions That Mimic The Conditions Of Oral Cavities Tea, Coffee, Orange Juice, Lemon Juice And Cola . All Discs Were Subjected To Translucency Test Using Portable Intraoral Digital Spectrophotometer (Vita Easy Shade) Against Black & White Backgrounds For Comparison With The Respective Control Groups.

Results: Regarding To Polishing & Glazing Tests Was The Only Significant Test From The Three Way ANOVA (p Value 0.001). Pressed Lithium Di Silicate Discs Were More Translucent In All Subgroups With High Statistical Significance (P Value <0.001). Pressed Lithium Di Silicate Discs Were Non-significant Before And After Emersion In Coloring Solutions And Aging Thermo-cycling Test. (P Value 0.336). Yttrium Stabilized Tetragonal Zirconia Discs Was Non-significant Before And After Emersion In Coloring Solutions And Aging Thermo-cycling Test When Subjected To Auto Glaze. (P Value 0.586). Tetragonal Zirconia Discs Were Significant Before And After Emersion In Coloring Solutions And Aging Thermo-cycling Test When Subjected To Add-on Glaze (P Value 0.175) And Traditional Polishing (P Value 1). Conclusion: It Could Be Concluded From This Study, That Pressed Lithium Di Silicate Was The Material Of Choice When It Comes To Esthetics As It Was More Translucent Than Yttrium Stabilized Tetragonal Zirconia & It Was Resistant To Staining By Food And Drinks, More Over It Was Highly Resistant To Ageing As Proven By Thermocycling.

Mohamed Gamal Hamdy Abddel-Aal, Cherief Adel Mohsen And Shams Waaz Amgad .,

ABSTRACT
Statement Of The Problem: Color Stability Of All Ceramic Restorations Cemented In The Oral Cavity Is Point Of Concern For Both Dentist And Patient. The Aim Of This Study Was To Evaluate Color Stability Of Zirconia Ceramic After Being Subjected To Aging.

Materials & Methods: Fifteen Zirconia Samples Were Constructed In The Form Of Discs By Copy Milling. All The Samples Were 5mm In Diameter But With Different Thickness. The Samples Were Divided Into Three Subgroups According To The Thickness Of The Ceramic C1:0.7mm, C2:1mm And C3:1.5mm. Spectrophotometric Measurements Were Made Before Aging And After Aging Where The Samples Were Immersed In Sodium Hypochlorite 1% For 15 Days As Aging And ?E Was Calculated. Data Were Tabulated And Statistically Analyzed Using One-way Analysis Of Variance (ANOVA). Result: The Most Color Change Occurred With 1.5mm Ceramic (?E:15.55�1.46), The 1mm Ceramic Had A Value About (?E: 5.2�1.27), While The Least Color Change Occurred With 0.7mm Ceramic (?E 3�0.82). Conclusion: There Was Increase In The Color Change With The Increase In The Thickness Of The Ceramic. Aging Had Significant Effect On The Color Stability Of Zirconia Ceramic With The Most Color Change Occured With The Higher Ceramic Thickness. Clinical Recommendation: Zirconia Should Not Be Used With A Thickness More Than 0.7mm To Attain Acceptable Color Stability.

Mahmoud Ahmed Kamel, Manal Rafei Hassan And Raiessa Mohammed Hashem .,

ABSTRACT

Objectives: The Purpose Of This Study Is To Investigate The Wear Of Recently Used CAD/CAM Ceramics Against Natural Tooth Structure In A Chewing Apparatus.

Materials and Methods: Thirty Rectangular Ceramic Samples (12x14x2) Were Divided Into Three Groups (n=10): Translucent Zirconia (Zr), Lithium Disilicate (e-max) And Hybrid Ceramic (vita Enamic). Natural Human Premolar Cusps Were Used As Antagonists. Ceramic Samples And Premolar Antagonists Were Dynamically Three-body Loaded In A Dual Axis Chewing Simulator With 49 N For 150,000 Loading Cycles. Wear Measurement For Ceramic Samples And Premolar Antagonists Were Calculated Using Weight Loss (gm.), And Surface Roughness Measurements (?m). Data Were Statistically Analyzed With One-way ANOVA Test, Followed By Post-hoc Test Between Groups.

Results: A Significant Difference Was Detected Between The Mean Values Of Weight Loss (gm.) Of The Three Tested Ceramic Materials And Their Premolar Antagonists With The Greatest Weight Loss Detected In Polymer-infiltrated Ceramics (Mean � SD: 0.0094�0.0028) Followed By Lithium-disilicate ( 0.0032�0.0009) And The Lowest Loss In Zirconia (0.0009�0.0002) And P Value Of (<0.001). For The Premolar Antagonists; The Greatest Loss In The Mean Weight Of Premolar Cusps Was Detected In Cusps Opposing Zirconia (0.0113�0.0018), Followed By Lithium-disilicate (0.0038�0.0009) And The Least Loss Detected In Cusps Opposing Polymer-infiltrated Ceramics (0.0003� 9) And P Value Of (<0.001). A Significant Difference In Surface Roughness (?m) In The Tested Ceramic Samples And In The Antagonistic Premolar Cusps. Surface Roughness Increased After Wear Testing But The Greatest Increase Was Found In Polymer-infiltrated Ceramic Samples (0.0056�0.0008) Followed By Lithium Disilicate (0.0033�0.0009) And The Least Change Was In Zirconia Samples (0.001�0.0003 And P Value Of (<0.001). Surface Roughness Of Zirconia Antagonistic Premolar Cusps Showed The Greatest Increase (0.0042�0.0007) Followed By Lithium-disilicate (0.0024�0.0009), While The Least Increase In Roughness Was In Cusps Opposing Polymer-infiltrated Ceramic Samples (0.0004�0.0001) And P Value Of (<0.001). Conclusion: Zirconia Showed The Best Wear Behavior Followed By Lithium-disilicate And Polymer-infiltrated Ceramics. Polymer-infiltrated Ceramic Is The Most Antagonist-friendly Among Tested Materials.

Hala Khaled Elsayed; Amal Hassan Abdel-Rahman And Dina Soliman Khater .,

ABSTRACT
Background: Head And Neck Cancer Among The Most Common Incident Cancers In Men Worldwide.�Early Detection Is The Key To Higher Survival Rate Against This Type Of Cancer. Cytokeratins Are Essential Intracellular Components, Reflecting Distinct Cellular Properties And Differentiation Stages In Epithelial Tissues. The CYFRA 21-1 Assay, Which Is The Soluble Fragment Of Cytokeratin 19, Has Been Proven Capable Of Early Detection Of Epithelial Carcinomas. This Study Was Conducted To Correlate The Immunoexpression Of CK 19 With The Concentration Of Its Salivary Fragments (CYFRA 21-1) For Early Detection Of Induced Dysplastic Changes Prior To Malignant Transformation In Experimental Rat. Conclusion: There Is A Positive Correlation Between CK 19 Immunoexpression In Tissue And The Level Of CYFRA 21-1 In Saliva.