Mostafa Elhussieny Mohammed Ismail And Cherif Adel Mohsen,

ABSTRACT
This Study Was Carried Out To Evaluate And Compare The Vertical Marginal Gap Distance,and Cyclic Loading Of All-ceramic Crowns Vita Suprinity And IPs E.max CAD (CAD/CAM Milling, Cerec MCXL), Using Two Types Of Finish Lines (deep Chamfer And Radial Shoulder). Specially Designed Stainless Steel Dies Were Constructed And A Total Number Of 40 Samples Were Constructed Representing Two Equal Groups (20 Samples), According To The Type Of Materials (VITA Suprinity And IPs E.max CAD ?CAD/CAM Milling Technique Cerec MCXL) The Twenty Samples Were Further Divided Into Two Divisions (10 Each) According To The Type Of The Finish Line Used (deep Chamfer And Radial Shoulder). Each Division Was Then Divided Into Two Classes (5 Each) (one Class Was Constructed As A Crown Coping And Then Veneered, The Second One Was Constructed As A Full Contoured Crowns). Vita Suprinity And IPs E.max CAD Crowns Were Fabricated Following A Standard Procedure And Standard Dimensions As Controlled By The Cerec MCXL Software. As Regard The Vertical Marginal Gap Test, The Results Showed That IPs E.max CAD Crowns Regardless To Finish Line Type And Veneering, Recorded A Higher Vertical Marginal Gap Mean Value (42.59�2.38 �m) Than Obtained With Vita Suprinity Crowns (36.11�1.76�m). Regardless To The Production Techniques And Veneering, Deep Chamfer Finish Line Recorded A Lower Vertical Marginal Gap Mean Value (37.94�2.11�m) Than Obtained With Radial Shoulder Finish Line (40.77�2.33�m). Regardless To Production Techniques And Finish Lines, Full Contoured Crowns Recorded A Lower Vertical Marginal Gap Mean Value (38.34�2.36�m) Than Obtained Veneering (40.36�2.10�m). The Cyclic Loading Test Data Revealed That IPs E.max CAD Crowns Recorded A Higher Fracture Resistance Mean Value (1013�53.84N) Than The Load Cycled Crowns (888.1�104.4N). Vita Suprinity Crowns Recorded A Higher Fracture Resistance Mean Value (803.7�66.45N) Than The Load Cycled Crowns (703.8�34.26N), Regardless To Finish Line Type And Veneering. The Cyclic Loading Test Data Revealed That IPs E.max CAD Crowns Recorded A Higher Fracture Resistance Mean Value (1013�53.84N) Than The Load Cycled Crowns (888.1�104.4N). Vita Suprinity Crowns Recorded A Higher Fracture Resistance Mean Value (803.7�66.45N) Than The Load Cycled Crowns (703.8�34.26N), Regardless To Finish Line Type And Veneering.

Heba M. A. Darwish, Mostafa A. M. Hassan, Eman A. Abou Auf And Reham A.F.Dwedar,

ABSTRACT
The Present Investigation Was Conducted To Assess And Compare The Antimicrobial Effect Of Five Traditional Plant Extracts (green Tea, Guava Leaves, Coffee, Clove And Ginger) Against Common Cariogenic Microorganisms. The Samples Of The Study Were Divided Into Two Main Groups Of 125 Filter Paper Discs Each, According To The Type Of The Inoculated Bacteria; B1: Streptococcus Mutans Group And B2: Lactobacillus Acidophilus Group. Then Each Group Was Further Subdivided Into Five Equal Subgroups Of 25 Discs Each, According To The Type Of Plant Extract Tested. The Cultivation Of The Plant Extracts Discs On The Culture Media Was Done Using The ?disc Diffusion Method?. The Antibacterial Behavior Of Each Plant Extract Was Assessed By Measuring The Diameter Of The Inhibition Zones By Millimeters In Comparison To The Positive Control (antibiotic Disc) And Negative Control (distilled Water Disc). The Results Showed That The Only Potent Antibacterial Plant Extracts Against Streptococcus Mutans And Lactobacillus Acidophilus Were Green Tea And Ginger. Guava And Clove Extracts Showed Antibacterial Effect On The Streptococcus Mutans Only, While Coffee Extract Showed Antimicrobial Effect Against Lactobacillus Acidophilus Only.

Islam Moftah, Enas Fathelbab And Mohammed M. Shalaby,

ABSTRACT

Objectives: The Aim Of The Study Was To Investigate The Influence Of Thermocycling On Shear Bond Strength Of Two CAD-CAM Fabricated Materials Luted To Teeth With Different Luting Agents. Methods: Thirty Six Freshly Extracted Sound Human Upper Six Molars Were Collected And Placed Into Color Coded Acrylic Molds. Occlusal Surfaces Of Teeth Were Reduced To Expose Dentin Then Flattened. Thirty Six Discs With 10mm Diameter And 1.5mm Thickness Were Milled Via CAD/CAM; Eighteen Of Vita Enamic And Eighteen Of Bio Hpp. Each Group Was Divided Into Three Subgroups According To The Used Luting Agent (six Samples Each). Subgroups (A1&B1) Luted By Vario-link, (A2&B2); Luted By Panavia And (A3&B3) Luted By Rely-X. All Samples Were Cemented Under Constant Static Load And Thermocycled 5000 Cycles Then Shear Bond Strength Was Tested. Data Were Collected, Tabulated And Statistically Analyzed Using SPSS. Failure Modes Were Evaluated Using SEM. For Parametric Data; One-way (ANOVA) Was Used To Analyze The Data, Followed By Scheffe?s Post-hoc. The Significance Level Was Set At P � 0.05.

Results: Statistical Analysis Revealed That There Is A Statistical Significant Difference Between Both Tested Materials At P Value 0.05. One Way Anova Revealed That There Was Statistical Significant Difference Between Mean Values Of SBS Of The Bio Hpp And Vita Enamic Among The Six Tested Sub Groups At 0.05 Level.Scheffe?spost-hoc Test Showed That Veriolink Luted Samples Of Both Tested Materials (VA& VB) Recorded The Highest Mean Values Of SBS. There Was No Statistical Significant Difference Between Subgroup (PB & RB). However There Was Statistical Significant Difference Between Mean Values Of SBS Of Both Subgroups To Those Of Subgroups (VA, PA& RA). All Tested Vita Enamic Subgroups Showed Mixed Mode Of Failure. Whereas, All Tested Bio Hpp Subgroups Showed Adhesive Failure Mode. Conclusion: Total Etch And Bond Resin Cements Yield The Highest Shear Bond Strength When Bonded To Bio Hpp And Vita Enamic, Self-etch Resin Cements Yield Low Shear Bond Strength When Bonded To Vita Enamic, While Self-adhesive Resin Cements Yield Low Shear Bond Strength When Bonded To Bio Hpp.

Noura M. El-Sherif And Enas Fathelbab,

ABSTRACT

Objectives: The Aim Of This Study Was To Find Out The Effect Of Home And Office Bleaching Agents On Color And Surface Roughness Of Different Thicknesses Of Hybrid Resin Ceramics. Methods: Forty Disc Shaped Samples (1 & 1.5mm Thick) Were Fabricated From Vita Enamic Shade (3M2-HT) And Lava Ultimate Shade (A3-HT) Hybrid Ceramics (20 Sample Each). Samples Of Each Subgroup Were Divided Into Two Classes According To The Used Bleaching Technique; (home And Office) (5 Samples Each). Surface Roughness Of All Samples Was Measured Before And After Treatment With Bleaching Agents Using A Tactile Profilometer. Color Measurements Were Done Using A Spectrophotometer For All The Samples Before And After Treatment With Bleaching Agents. Three-way (ANOVA) Was Used To Analyze The Data, Followed By Bonferroni?s Post-hoc Test. The Significance Level Was Set At P � 0.05.

Results: The ?E Values Of The Tested Materials Were Affected By Bleaching Technique And The Ceramic Thickness. The Mean Values Of (?E) For 1 Mm Thick Samples Were Higher Than Those Of 1.5 Mm Thick. The Mean Values Of (?E) For Home Bleaching Technique Samples Were Lower Than Those Treated With Office Bleaching Technique. All Samples Showed An Increase In Surface Roughness (Ra) Values After The Used Bleaching Techniques. Conclusion: Home And Office Bleaching Techniques Recorded Clinically Imperceptible Color Changes. Home Bleaching System Affected Surface Roughness Of Both Tested Materials.

Maged Saleh Alkhuzae, Lamiaa Sayed Kheiralla And Gihan AbdElhady Elnaggar,

ABSTRACT


Purpose: The Purpose Of This Study Was To Compare Hybrid Ceramic Veneers And Pressable Laminate Veneers Regarding Resistance To Fracture Of Both Materials Following Thermal Cycling.

Materials and Methods: A Total Of Twenty Four Of Comparable Human Central Maxillary Incisors Were Extracted For Periodontal Reason, Were Selected For The Present Study. The Samples Were Divided Into Two Main Groups According To The Material Used For Construction Of Laminate Veneers Restoration. The Vita Enamic Hybrid Ceramic Laminate Veneers Were Fabricated From Vita Enamic Blocks Milled By A Cerec In-Lab CAD/CAM Machine. While The IPS E.max Press Ceramic Laminate Veneers Were Fabricated From Machinable CAD/CAM Wax Discs (CAD Wax) To Have Equal And Standardized Thickness Of All Samples. All Samples Were Subjected To Thermocycling Between 5C� To 55C� In Water Bath For A Total Of 1750 Cycle With 10 Seconds Dwell Time At Each Bath Using Thermocycling Device. The Fracture Load Strength Test Was Performed Using The Universal Testing Machine. Result: It Was Found That IPS Emax Ceramic Press Group Recorded Higher Mean Value Of Fracture Resistance (430.4 � 47.7 N) When Compared Vita Enamic Hybrid Ceramic Group (289.02 � 87.24N) With No Statistically Significant Difference (P>0.05) Between Two Groups As Indicated By Student T-test Conclusion: IPS Emax Ceramic Press Veneer Materials Recorded Higher Mean Value Of Fracture Resistance When Compared Vita Enamic Hybrid Ceramic Veneer Materials With No Statistically Significant Difference

Wasfi A. Qaid , Mohamed R. Farid And Mohamed F. Haridy,

ABSTRACT
Statement Of Problem: All-ceramic Onlay Has Become More Popular In Dental Clinics Due To Their Lifelike Appearance, Durability, And Biocompatibility. However, Their Drawbacks Include Fracture Susceptibility And Inadequate Marginal Fit And Fracture Susceptibility.

Purpose: The Aim Of This Study Was To Compare Hybrid Ceramic And Pressable Ceramic Onlay Restoration Regarding Vertical Marginal Discrepancy Of Both Materials Following Thermal Cycling.

Materials and Methods: A Total Of Twenty Four Extracted Intact Molar Were Fixed In Epoxy Resin. Standardized Onlay Preparation Was Performed On All Specimens By Computer Numerically Controlled Milling Machine (CNC). The Samples Were Divided Into Two Main Groups (I-Vita Enamic Hybrid Ceramic Materials & II- IPS E.max Press Ceramic Materials) According To The Ceramic Material Used For Construction Of Onlay Restoration. All Onlay Ceramic Restorations Were Fabricated And Treated And Cemented On The Prepared Teeth. All Samples Were Subjected To Thermocycling Between 5C� To 55C� In Water Bath For A Total Of 2000 Cycle With 10 Seconds Dwell Time At Each Bath Using Thermocycling Device. The Marginal Gap Distance Between The Outer Margins Of Each Onlay And The Shoulder Finish Line Of Prepared Tooth In A Vertical Direction Was Measured. The Data From The Two Groups Were Collected, Tabulated And Statistically Analyzed. The Results Were Analyzed Statistically Using Student?s ?t? Test. The Level Of Significance Was Taken At P < 0.05. Result: It Was Found That Vita Enamic Hybrid Ceramic Onlay Group Recorded Statistically Significant (P<0.016), (P<0.001), (P<0.0001), And (P<0.0001) Higher Vertical Marginal Gap Mean Value When Compared To IPS Emax Ceramic Onlay Group.

Conclusions: The Material Used For Fabrication Of The Indirect Ceramic Restorations Has A Crucial Effect On Its Performance Regarding The Marginal Gap. Differences In Marginal Fit Were Recorded For Ceramic Partial Restorations Fabricated By Different Manufacturing Techniques E.g. IPS E.max Press Ceramic Was Better In The Marginal Sealing Values Than The Vita Enamic Ceramic Onlay.

Mostafa Abd El Hamid Abd El Ghany, Ahmed Gamal Ahmed Hassan And Emad Mohamed Tolba,

ABSTRACT


Introduction: Removable Prostheses Are Provided To Enable Oral Masticatory Function And To Improve The Quality Of Life For Edentulous Patients. The Main Objective In Denture Fabrication Is The Preservation Of The Remaining Oral Structures. In This Regards Efforts Should Be Made To Decrease Stresses To Residual Alveolar Ridges. Aim Of The Study: To Evaluate And Compare The Effect Of Ball And Socket And Bar Attachments On Supporting Structures In Implant Supported Overdenture Using Three Dimensional Finite Element Analysis (3D FEA).

Materials and Methods: A Three Dimensional (3D) Digital Model Simulating An Edentulous Mandible And A Mandibular Over Denture Was Constructed. The Mandibular Over Denture Was Supported By Two Implants Placed In The Canine Region Bilaterally With Ball And Socket Attachment In One Model (model I) And Bar Attachment In The Other Model (model II). The Digital Model Was Created From Scanning Of Edentulous Natural Mandible And A Suitable Set Of Anatomical Artificial Teeth By Identica Hybrid 3D Dental Scanner. The Stimulated Denture As Well As The Mucosa Was Drawn By Solid Work Software 2017.

Results: The Stresses Generated In Case Of Using Ball And Socket Attachment Were In General Less Than Those Generated In Case Of Bar Attachment. The Exceptions Were In Case Of Spongy Bone And Mucosa. Conclusion: Ball And Socket Attachment System Transmitted Lesser Amount Of Stresses To The Implants As Compared To The Bar-Clip Attachment System.

Ahmed M. Abou-Aly, Fatma A. El-Hendawy And Manal A. El-Ebiary,

ABSTRACT

Objectives: The Aim Of This Study Was To Evaluate Microleakage Of Bioactive Composite When Used In Class I Primary Molars.

Materials and Methods: Thirty Sound, Non-restored Freshly Extracted Human Primary Molars Were Included In The Study, Teeth Were Collected From The Pediatric Dentistry Department, Faculty Of Dentistry, Tanta University And From Private Clinics. A Standard Class I Cavity Was Prepared On The Occlusal Surface Of Each Tooth. The Scotchbond Universal Adhesive System Was Applied To All Prepared Teeth Then Cured With LED Curing Unit. Then Teeth Were Randomly Divided Into Two Groups (n = 15). Group A: ?Activa?; Group B: ?Filtek Z250 XT?. Then All The Samples Were Subjected To Thermocycling For 1000 Cycles At 50C And 550C And Covered With Nail Varnish. Later, Samples Were Immersed In 2% Methylene Blue Dye For 24 H. Teeth Were Sectioned Longitudinally In A Mesiodistal Direction And Studied Under A Stereomicroscope For Dye Penetration. Data Obtained Were Analyzed Using Independent T-test.

Results: The Mean Microleakage Value Of ?Activa? Was Lower Than Mean Microleakage Value Of ?Filtek Z250 XT? With No Significant Difference Conclusion: There Was No Statistically Significant Difference In Mean Microleakage Values Of Bioactive Composite ?Activa? And Nanohybrid Composite ?Filtek Z250 XT?.

Angham Ibrahim El-Gendy, Mohamed Farag Ayad And Amany Mohammed Korsel,

ABSTRACT


Purpose: To Evaluate The Fatigue Resistance Of High Translucent Zirconia And Hybrid Ceramic Posterior Occlusal Veneer.

Materials and Methods: Forty Freshly Extracted Human Molars Were Received Standardized Tooth Preparations Replicating A Worn Occlusal Table By Using A Diamond Saw By Removing All Coronal Tooth Structure 4 Mm Occlusal To The CEJs Leaving Exposed Dentin Centrally And Peripheral Enamel. Intra-enamel Indexing Notches Were Created Proximally. The Specimens Were Divided Into 2 Groups Based On Restorative Materials Each Group Included Twenty Teeth For Each Group. Group I: High Translucent Zirconia (Bruxzir Anterior), Group II: Polymer Infiltrated Ceramic (Vita Enamic). The Restoration Thickness Was 1 Mm At The Fossa And 1.5 Mm At The Cusp Tip. The Specimens Were Cemented By Self-etch Resin Cement (Panavia F2.0). Half Of The Specimens Of Each Group(10 Specimen) Were Subjected To Fracture Resistance Test While The Other Half Subjected To Thermocycling (15000 Cycles, 5-55 C, 30 Sec Dwell Time) And Chewing Simulator With A Load 150 N Which Was Applied For 600,000 Cycles To Simulate 2.5 Years With A Loading Frequency 6 HZ. Specimens That Survived Cyclic Loading Were Loaded Until Failure, To Calculate The Residual Fracture Strength After Fatigue. Mean Values For Each Group Were Calculated, And Differences Between The Groups Were Tested For Statistical Significance By Use Of 2-way Analysis Of Variance (ANOVA).

Results: Both Material And Fatigue Test Had Significant Effect On The Fracture Resistance Where (P-value<0.001). According To The Material Type; P-value Was High Significante As The Bruxzir Anterior Had A Higher Mean Of Fracture Resistance Than The Vita Enamic. According To The Fatigue Test For Bruxzir Anterior ,the P-value Was High Significant As The Mean Of The Initial Fracture Resistance Was 2240.60� 139.90 Which Is Higher Than The Mean Of The Specimen After Subjected To Fatigue Test 2019.88 � 132.29. For The Vita Enamic The P-value Was High Significant That The Mean Of The Initial Fracture Resistance Was 744.58 �99.23 Which Is Higher Than The Mean Of The Specimen After Subjected To Fatigue Test 596.45 �81.13. The Coefficient Of Variation Showed That For Bruxzir Anterior The Specimens Lost About 22 % Of Their Initial Fracture Resistance After They Were Subjected To Fatigue While The Vita Enamic Specimens Lost About 19 % Of Their Initial Fracture Resistance. Conclusion: Within Limitations Of This Study, High Translucent Zirconia Posterior Occlusal Veneers Can Resist Cyclic Loading That Represent Several Years In Patient Mouth, The Percentage Of The Loss In The Initial Fracture Resistance Of Both Material After Subjected To Chewing Simulator Was Approximated To Each Other, However More Researches Are Required To Prove The Use Of Polymer Infiltrated Ceramic As Posterior Occlusal Veneers.

Diaa Eldin Abulhassan Mosref, Magdy Mohamed Ali And Mohamed Medhat Kataia,

ABSTRACT


Introduction: The Aim Of The Study Was To Compare Between WaveOne Gold And WaveOne Reciprocating Files Concerning Surface Topography Analysis Using (SEM) And Changes In Canal Curvature Using (CBCT). Methods: A Number Of Extracted Mandibular Molars Were Collected, Their Mesial Roots Were Cut Using Diamond Disk. The Preoperative Angle Of Curvature Was Measured According To Schneider Technique On CBCT Images Scans. Seventy Two (72) Roots With Curvature Angles Ranges From 5o To 45o Were Selected For This Study Then Canal Preparation Was Done Using WaveOne Gold And WaveOne Files. The Angles Of Curvature Were Measured After Instrumentation And Comparison Was Done By Fusion (superimposition) Of The Pre-operative And Post-operative Cone Beam Scans. WaveOne Gold Files And WaveOne Files Were Scanned Using SEM Before And After Preparing 3,6,9 Canals. One Way-ANOVA Was Used To Study The Effect Of Different Groups On Mean Canal Curvature And Measurements Of Canal Transportation. Statistical Analysis Was Performed With IBM? SPSS? Statistics Version 21 For Windows.

Results: It Was Found That ?WaveOne Gold? File System Has Recorded Lower Statistically Significant Degree Of Canal Transportation After Instrumentation Than The ?WaveOne? File System (p<0.05), Also There Was Statistically Significant Effect Of Canal Curvature On The Degree Of Canal Transportation After Instrumentation (p>0.05), As There Was Statistically Significant Difference In Canal Transportation In Both Subgroups (?5?-25?? And ?25?-45??). SEM Analysis Showed A Range Of Defects Detected On ?both Files? In Their New As Well As In Their Used Condition. Defects As Strips, Debris, Pitting Micro-fracture, Cracks, Corrosion, Fretting And Scrapping. Conclusion: It Was Found That WaveOne Gold Reciprocating File Is Superior In Preserving Canal Curvature Than WaveOne File