Fady A. Issa, Hesham Katamish And Tarek Salah Morsi,

ABSTRACT
The Purpose Of This Study Was To Evaluate The Performance Of New Hybrid-ceramics As Anterior And Posterior Implant Supported Abutments Under Cyclic Loading As A One-piece Hybrid Abutment And Measure Their Fracture Resistance. 20 Implant Analogues Were Embedded In Acrylic Resin Blocks. Titanium Base Was Placed And Scanned. Samples Were Designed As Upper Central Incisors And Upper First Premolars Using Exocad Software For CAD/CAM Milling Using VITA ENAMIC Blocks. All Abutments Were Permanently Cemented To Titanium Base Using Resin Cement. All Samples Were Subjected To Cyclic Fatigue Loading Followed By Fracture Resistance Testing Of Surviving Specimens. Posterior One-piece Hybrid Abutment Samples Showed Higher Survival Rate Than Posterior One-piece Abutments During Cyclic Loading. The Mean Fracture Loads Of The One-piece Hybrid Abutments Both Anterior & Posterior Were 304 N And 417.6 N Respectively. Fractographic Analysis Confirmed That Crack Originated From The Occlusal Surface (under The Indenter) And Spread To Restoration Margins, Which Lead To Clean Bulk Fracture Of The Samples.

Basmah El-Sayed, Fatma Mohamed, Rehab R. El-Zehery And Mohammed Grawish,

ABSTRACT
Periodontal Disease Is Currently One Of The Major Health Problems Worldwide. Unfortunately Once The Periodontal Tissues Are Destructed, Periodontal Regeneration Is Quite Difficult And Current Regenerative Techniques Do Not Produce Satisfactory Results. Recently Many New Regenerative Therapies Have Emerged And Are Considered Favorable Candidates For Periodontal Regeneration. Rats Serve As One Of The Suitable And Most Common Animal Models Used In Preclinical Experiments Evaluating New Treatments For Periodontal Regeneration.

Hossam Hassan Soliman Hassan, Amal Hessein Mubarak, Fatema El Zahraa Awad Sayed, Ahmed Mohamed Osama And Sherihan Mohamed Eissa Ali,

ABSTRACT
Background: Fracture Strength And Hardness Could Be Found To Be Sensitive To The Curing Techniques Of The Polymerized Resins; The Hardness Is An Efficient Technique To Judge The Polymerisation Depth Of Resin Materials.

Aim: Compare The Effect Of Curing Techniques On The Fracture Resistance Of Implant Retained Acrylic Resin Overdenture Bases. Method: Acrylic Resin Denture Bases Had Been Divided Into Three Groups According To The Technique Of Polymerization (group I: Heat Cured Acrylic Resin, Group II: Microwave Cured Acrylic Resin, Group III: Light Cured Acrylic Resin). Universal Testing Machine Had Been Used To Measure Fracture Strength And Vicker`s Hardness Tester Had Been Used To Measure Vicker�s Hardness.

Results: Light Cured (Eclipse) Denture Base Resin Revealed Significantly Higher Fracture Strength And Hardness Properties, As Compared To The Water Bath And Microwave Polymerization Methods. Conventional Heat Cured Resin Demonstrated Significantly Higher Fracture Strength And Hardness Properties, As Compared To Microwave Polymerized Resin. Conclusion: High Strengths Exhibited By Eclipse Is Also Concerning The High Degree Of Polymerization And Crystalline Nature Of The Formulation Moreover As Less Voids Among The Material

Mustafa M. Abdullah, Manal R. Hassan And Raiesa M. Mohammed,

ABSTRACT
Objective: The Purpose Of This Study Was To Assess Fracture Resistance Of Endocrown Constructed Of Two Different Materials Namely IPS E.max And Hybrid Ceramic Compared To Conventional Post And Core And IPS E.max Full Coverage Crown. Materials And Methods : Thirty Sound Extracted Human Permanent Mandibular Molars (N =30) Were Endodontically Treated. Standardized Preparations Were Done With 3-mm Intracoronal Extensions Into The Pulp Chamber And Divided Into 3groups Of Each (n=10). Group I : Specimens Involved Endodontically Treated Mandibular Molars Restored With Glass Fiber Posts Cemented With Rely X Cement, Composite Cores Were Built Up And IPS E.max Press Full Coverage Crowns (control Group) .Group II: Involved Endodontically Treated Mandibular Molars Restored With IPS E.max Press Endocrown. Group III: Specimens Involved Endodontically Treated Mandibular Molars Restored With Hybrid Ceramic Vita Enamic Endocrown. Each Group Of II And III Subdivided Into Sub-groups According To Ferrule Preparation GPIa (n=5) With Ferrule And GPIIb(n=5) Without Ferrule. Specimens Were Subjected To Fatigue By Cyclic Loading 150,000 Cycles In Order To Simulate A Clinical Service Time Of 1years And Were Mounted In A Universal Testing Machine(instron) And Then They Subjected To Vertical Compression Load Until Failure. Data Were Collected, Tabulated And Statically Analyzed. One Way ANOVA Followed By Pair-wise Tukey�s Post-hoc Tests Were Performed To Detect Significance Between Groups. Student T-test Was Done Between Subgroups. Result: The Highest Fracture Resistance Mean Value Was Recorded For Vita Enamic Endocrown With Ferrule Group (1405.69�34.7 N) While The Lowest Fracture Resistance Mean Value Was Recorded For Vita-enamic Endocrown Without Ferrule Group (847.04�45.54 N). Difference Between Control Group And Vita Enamic Endocrown With Ferrule Group While Without Ferrule The Difference Was Significant (p<0.05) Conclusion: Endocrowns Preparation With 1mm Ferrule And Vita Enamic Material Can Be The Best Of Choice To Achieve A Higher Fracture Resistance In High Stress Bearing Areas. KEY WORDS: Endocrown, Endodontically Treated Molars Reinforced With Post And Core, IPS E.max Crown, Hybrid Ceramics Vita Enamic.

Basma A. Alrazhi, Alaa H. Diab And Shaimaa Gawdat,

ABSTRACT
This Study Was Conducted To Evaluate Postoperative Pain After Root Canal Preparation With ProTaper Next And WaveOne NiTi Systems. Fifty Two Patients With Mandibular Permanent Premolars And Molars, Showing Signs/symptoms Of Symptomatic Irreversible Pulpitis Were Selected From The Outpatient Clinic Of Endodontic Department, Cairo University. An Approval From The Ethic Committee And An Informed Consent From The Patients Were Taken. Patients Were Randomly Divided Into Two Groups; Comparator Group: Root Canal Instrumented With WaveOne Instruments (n=26), And Intervention Group: Root Canal Instrumented With Protaper Next (PTN) Instruments (n=26). Postoperative Pain Was Recorded Using Numerical Rating Scale (NRS) At 6, 12, 24, 48 Hours Intervals. Results Showed That A Significantly Lower Levels Of Postoperative Pain In The PTN Group Compared To WaveOne Group At 6 And12 Hours. No Significant Difference Was Found Between Both Groups At 24 And 48 Hours. In Conclusion, PTN Rotary System Was Able To Minimize The Risk Of Postoperative Pain Intensity, As Compared To WaveOne Reciprocating System In The First 24 Hour.

Ehab Mohmed Abd-Al Halim, Maged Gaber M. El Saadawy And Alaa Bashir Kassem,

ABSTRACT
Background: The Purpose Of This Prospective Study Is To Compare Between Effects Of Two Occlusal Systems On The Biting Force And Masticatory Efficiency Of Implant Bar Retained Mandibular Over Denture Opposed By Maxillary Complete Denture. Methods: After Evaluation Of 10 Completely Edentulous Patients Using Panoramic X-ray, Mucoperiosteal Flaps Were Reflected Exposing The Mandibular Interforaminal Region. Two Implants Were Placed In The Interforaminal Region For Each Of The 10 Patients. After A Healing Period Of 3�months, Acrylic Maxillary And Mandibular Overdentures Were Fabricated With Bilateral Balanced Occlusion For All Patients, Positioner Attachments Were Used And Incorporated Into The Dentures Using Direct Pickup Method. All Patients Used Their Dentures With Bilateral Balanced Occlusion For 1�month As Adaptation Period Then Were Evaluated 3-6-9 Months. Following Evaluation At 9 Months Post Insertion, It Was Converted Into Canine Guidance Occlusion Using The Same Denture. This Was Achieved Clinically By Remounting Using The Semi-adjustable Articulator. Light-cured Composite Resin Was Then Added In The Mandibular Canines To Provide An Interarch Disocclusion Space Of 2�mm During Eccentric Movements.Then Evaluated After3-6-9 Months For The New Occlusion Then Comparing The Results Of Masticatory Efficiency And Biting Force For Both Types Of Occlusion. Results : The Results Of This Study Showed No Significant Difference For The Masticatory Efficiency And Biting Force Between The Occlusal Concepts Proposed.

Conclusions: Both Bilateral Balanced Occlusion And Canine Guidance Occlusion Can Be Used Successfully In Implant-retained Mandibular Overdentures Without Affecting Masticatory Efficiency And Biting Forces.

Sherif Z. Hassan, Enas Fathelbab And Mohammed M. Shalaby,

ABSTRACT

Objectives: The Aim Of This Study Was To Determine The Effect Of Different Hybrid Ceramics Thicknesses And Different Luting Agent Shades On The Perceived Final Color Of The Restoration. Methods: Forty Disc Shaped Samples (0.5 & 1mm Thick) Were Fabricated From Vita Enamic Shade (3M2-HT) And Lava Ultimate Shade (A3-HT) Hybrid Ceramics (20 Sample Each). Resin Composite Discs (10 Mm Diameter & 2 Mm In Thickness) Shade A4 Was Used To Simulate The Color Of A Dark Underlying Substrate (n=40). Cementation Of Discs Was Carried Out With Rely X Veneer Shade A3 Opaque, Translucent Or Without Cement (control Group). Color Differences (?E) Were Determined Using Spectrophotometer. For Parametric Data; Three-way (ANOVA) Was Used To Analyze The Data, Followed By Bonferroni�s Post-hoc. The Significance Level Was Set At P ? 0.05.

Results: The L* A* B* Values Of The Tested Materials Were Affected By Both Luting Agent And The Ceramic Thickness. The Mean Values Of (?E) For 0.5 Mm Thick Samples Were Higher Than Those Of 1 Mm Thick. The Mean Values Of (?E) For Opaque Luting Agent Samples Were Higher Than Those Of Luted With Translucent Luting Agent. Decrease In Mean Values Of (?L) Of All The Tested Samples Was Detected. Conclusion: Both Tested Materials Luted With Translucent Luting Agent Recorded Clinically Acceptable Color When Used In 1mm Thickness. The Tested Luting Agent Shades Made The Final Color Of The Samples Darker Than The Control Group.

Omnia Badawy Darwish, Siza Yacoub Zakhary And Sherif Adel El-khodary,

ABSTRACT
OneShape Is A Single-file NiTi System That Uses Full-sequence Rotary Motion. The File Has Three Variable Cross-sections Along The Length Of The Blade Also It Has A Longer Pitch. These Properties Cause Reduction Of The Preparation Time, Efficient Cleaning, Decrease In The Bacterial Charge Similar To That Of Traditional Instruments And Lower Quantity Of Apically Extruded Debris. Root Canal Preparation Techniques May Cause Postoperative Pain. The Goal Of The Present Study Was To Compare The Intensity Of Postoperative Pain When Using OneShape Or ProTaper Universal System For Instrumentation Of Root Canals. Methods: Forty Patients Who Fulfilled Specific Inclusion Criteria Were Assigned To Two Groups According To The Root Canal Instrumentation Technique Used, OneShape Or ProTaper Universal. Root Canal Treatment Was Carried Out In Single Visit, And The Severity Of Postoperative Pain Was Assessed By Numerical Rating Scale (NRS) Score After The Session Until Complete Pain Relief Was Achieved. Analgesic Consumption Was Also Recorded.

Results: Mean Of NRS Scores Between The Two Groups And Within The Same Group At Different Follow Up Periods(6, 12, 24 And 48 Hours) Showed No Statistically Significant Difference. Also, There Was No Statistical Significant Difference In Analgesic Consumption Between The Two Groups.

Ahmed M. Metwally, Neven S. Abdou And Manal F. Osman,

ABSTRACT


Purpose: This Study Was Conducted To Evaluate The Effect Of Biodegradation Of Orthodontic Archwires In Different Solutions On Metal Ions Release, Surface Microhardness, Modulus Of Elasticity And Flexural Strength.

Materials and Methods: Four Orthodontic Archwires (stainless Steel, NiTi, Copper NiTi And Teflon-coated NiTi) Were Used. They Were Immersed In Different Solutions (distilled Water, Artificial Saliva, Tea, Hot Water, Coca Cola And Cold Water) For Four Weeks. A Total Number Of 460 Archwire Specimens Were Used In This Study. They Have Been Classified As Follow, 100 Archwire Specimens Were Prepared For Measurement Of Released Metal Ions After Immersion In Each Solution And 360 Archwire Specimens Were Prepared For Determination Of Their Mechanical Properties. For Metal Ions Release Assessment, The Specimens Were Classified Mainly Into Four Groups (25 Specimens Each) According To The Archwire Type. Each Group Was Further Subdivided Into 5 Subgroups (5 Specimens Each) According To The Used Solution. Each Subgroup Had Been Divided Into Two Divisions As The Following: Five Solutions As Test Specimens Immersed With Studied Archwires And Five Solutions As Control Specimens Without Archwire. Metal Ions Release Analysis Was Performed For All Solutions For Nickel, Chromium, Copper, Cobalt, Iron And Titanium Metal Ions In Parts Per Billion (ppb) Using Inductively Coupled Plasma Atomic Emission Spectrometer (ICP Spectroscope). For Mechanical Properties Assessment, The Specimens Were Classified Mainly Into Four Groups (90 Specimens Each) According To The Archwire Type. Each Group Was Further Subdivided Into 6 Subgroups (15 Specimens Each) According To The Used Solution. Each Subgroup Had Been Divided Into Three Divisions (5 Specimens Each) According To The Test Parameter (surface Microhardness, Modulus Of Elasticity, Flexural Strength). Surface Microhardness Was Evaluated Using Vickers Hardness Tester. While Modulus Of Elasticity And Flexural Strength Were Measured By Subjecting The Archwires Specimens To The Three Point Bending Test Using A Universal Testing Machine. Means And Standard Deviations Were Calculated For All Tests. The Data Was Analyzed And Compared Using Two-way ANOVA Analysis And Least Significant Difference (LSD) Test (p < 0.05).

Results: Artificial Saliva Significantly Decreased The Surface Microhardness Of St. St. And Teflon-coated NiTi Archwires And Significantly Decreased The Modulus Of Elasticity Of NiTi, CuNiTi, St. St. Archwires. Tea And Coca Cola Significantly Decreased The Surface Microhardness Of CuNiTi, St. St. And Teflon-coated NiTi Archwires And Significantly Decreased The Modulus Of Elasticity Of All Archwire Specimens. Immersion Of Orthodontic Archwire Specimens In The Testing Solutions Resulted In Release Of Minute Amounts Of Metal Ions.

Conclusions: Artificial Saliva, Tea And Coca Cola Potentially Would Contribute To Biodegradation Of Orthodontic Archwires Leading To Prolonged Orthodontic Treatment And Might Damage The Surface Of Archwires. The Realative High Temperatures Of Tea And Hot Water Played An Important Role In The Release Of Metal Ions With Subsequent Significant Decrease On The Mechanical Properties Of Orthodontic Archwires. The Released Metal Ions From Archwires Were Of Such Small Amounts To Be Of Any Biologic Risk. The Quantity Of Released Metal Ions Was Within Acceptable Biocompatible Limits.

Dina Ahmed AbdEllatif , Lamiaa Sayed Kheirallah And Maha Ahmed Taymour,

ABSTRACT
Conservation Of The Tooth Substance Connected With Aesthetic Treatment Modalities For Teeth Led To Rise In The Placement Of Indirect Restorations; Inlay, Onlay, Endo-crown, Veneer, Partial Coverage And Full Coverage Restorations In The Recent Years. The Aim Of This Study Was To Evaluate The Shear Bond Strength Of Vita Enamic Discs Bonded To Enamel And Dentin Using Bifix QM Resin Cement Versus Rely X Ultimate Resin Cement.

Materials and Methods: Twenty Eight Human Premolar Teeth Were Selected Then Divided Into Two Main Groups According To The Cement Used Then Further Subdivided Into Two Subgroups According To The Dental Substrate Either Enamel Or Dentin (n=7). Ceramic Discs Of 2mm Height And 4mm Diameter Were Cemented By Relay X Ultimate As A Control And Bifix QM As An Intervention. All Specimens Were Stored In Distilled Water For 24hr At 37?. The Specimens Were Loaded Until Fracture In A Shear Test At A Crosshead Speed Of 0.5mm/min In A Universal Testing Machine After Thermocycling.

Results: Relay X Cement Showed Significant Higher Shear Bond Strength In Enamel Substrate. Bifix QM Cement Showed Non Significant Higher Bond Strength In Dentin Substrate.

Conclusions: Rely X Ultimate Becomes The Cement Of Choice In The Cementation Of Conservative Restoration As Veneers. Both Cements Can Be Used For Bonding Vita Enamic Restorations With More Preferences To Bifix QM Cement When Most Of The Preparation In Dentin.