2017 Oregon Dental Conference Course Handout

Transcription

1 217 Oregon Dental Conference Course Handout Jim Kessler, DDS Course 8115: Merging Today s Restorative Options with Proven Principles: A Blueprint for Success Thursday, April 6 9 am - 12 pm

2 Proven Principles A Look at New Materials... Through the Lens of Proven Principles Oregon Dental Conference April 6, 217 Portland, Oregon Dr. James Kessler jim.kessler52@gmail.com At the end of this presentation participants should be able to: -understand the physical properties for all-ceramic materials with particular emphasis on what most frequently leads to failure -determine the most appropriate restorative material and design for each clinical situation -understand the preparation designs and laboratory communications necessary to maximize results with today s ceramic materials -con idently discuss the risks and bene its of contemporary restorative options with their patients and laboratory technician Good science happens slowly! You & I do the clinical research for new materials! Proven Principles Good science happens slowly! With ceramic materials, the clinical (in-vivo) performance is routinely inferior to laboratory (in-vitro) results With bonding procedures, clinical (in-vivo) performance is routinely inferior to laboratory (in-vitro) results When there s smoke-there s often fire Goals for Our Time Together Understand the physical properties of the various all-ceramic materials with particular emphasis on what frequently leads to failure Understand the indications and limitations of the current all-ceramic restorative options to determine the most appropriate material for each situation Enhance your ability to confidently discuss the risks and benefits of contemporary restorative options with patients and laboratory technicians Recognize clinical situations for which gold and PFM restorations remain the restorations of choice Goals for Our Time Together Understand the physical properties of the various all-ceramic materials with particular emphasis on what frequently leads to failure Properties of the ideal C & B material Ceramic materials do not fail because they are weak, They fail because of fatigue and defect propagation Wear resistance equivalent to or lower than enamel Gold Resin All Tooth Colored Restorative Materials Fatigue with Time and Function Result=Delayed Failure! Gold Fracture-proof in dimensions of Gold 1 mm or less Predictably Bondable-Conservative Etch-able Ceramics preparations All-Ceramic Restorations Maximum Esthetics Economics/Efficiency Conservation of tooth structure Metal-free restorations Ceramic materials do not fail because they are weak, They fail because of fatigue and defect propagation Result=Delayed Failure! Dr. Terry Donavan - Lecture to AES Fracture rates of IPS Empress all-ceramic crowns-a systematic review Heintze, Rousson International Journal of Prosth., 21 Most fractures 3-6 years

3 All Tooth Colored Restorative Materials Fatigue with Time and Function Understanding All-ceramic material limitations Damage due to instrumentation Ceramic materials do not fail because they are weak, They fail because of fatigue and defect propagation Single Load to Fracture Effect of Surface Damage Usually results in catastrophic failure Typical failure mechanism with thin samples 7 N Ceramic fatigue is dramatically accelerated with sliding contact in a moist environment! damage to intaglio surface significantly weakens N Simulated Dentin Overview: damage in brittle layers structures from Lawn, B, et al, J. Material Research, Radial Crack 22 Understanding All-ceramic material limitations Understanding All-ceramic material limitations Understanding All-ceramic material limitations Single Load to Fracture May occur at each layer junction More prone to occur with thicker samples & softer ceramics Usually results in catastrophic failure Typical failure mechanism with thin samples Cone Crack May occur at each layer junction Layered All-Ceramics are more susceptible to fracture than Monolithic Ceramics Radial Crack Radial Crack Understanding All-ceramic material limitations More prone to occur with thicker samples & softer ceramics Understanding All-ceramic material limitations Sliding contact fatigue damage in layered ceramic structures Understanding All-ceramic material limitations Sliding contact fatigue damage in layered ceramic structures Cone Crack Results in surface defects which have been shown to increase abrasion potential Outer Cone Crack Kim, Kim, Thompson, Zhang JDR, 27 Outer Cone Crack Kim, Kim, Thompson, Zhang JDR, 27 Inner Cone Crack Inner Cone Crack Uniaxial 2, cycles

4 Understanding All-ceramic material limitations Understanding All-ceramic material limitations Understanding All-ceramic material limitations Outer Cone Crack Outer Cone Crack Outer Cone Crack Crack depth in microns 1² 1¹ Failure line Inner Cone Crack Crack depth in microns 1² 1¹ Uniaxial Outer Cone Inner Cone Crack Crack depth in microns 1² 1¹ Uniaxial 2, cycles Uniaxial Inner Cone Outer Cone Inner Cone Crack 1⁰ 1¹ 1² 1³ 1⁴ 1⁵ 1⁰ 1¹ 1² 1³ 1⁴ 1⁵ 1⁰ 1¹ 1² 1³ 1⁴ 1⁵ Number of 12 N Number of 12 N Number of 12 N Sliding contact fatigue damage in layered ceramic structures Kim, Kim, Thompson, Zhang JDR, 27 Inner Cone Crack Sliding contact fatigue damage in layered ceramic structures Kim, Kim, Thompson, Zhang JDR, 27 Biaxial 3 cycles Crack depth in microns 1² 1¹ 1⁰ Failure Uniaxial 2, cycles 1¹ 1² 1³ 1⁴ 1⁵ Number of 12 N Proven Principles Good science happens slowly! With ceramic materials, the clinical (in-vivo) performance is routinely inferior to laboratory (in-vitro) results With bonding procedures, clinical (in-vivo) performance is routinely inferior to laboratory (in-vitro) results Sliding contacts dramatically accelerate fatigue Monolithic is more fracture resistant than layered Fracture rates of IPS Empress all-ceramic crowns-a systematic review Heintze, Rousson International Journal of Prosth., 21...the material should not be used in patients with confirmed or suspected bruxism....the material should not be used in patients with confirmed or suspected bruxism. A ceramic layer of sufficient thickness needs to be ensured...the material should not be used in patients with confirmed or suspected bruxism. The evidence

5 Fracture-proof in dimensions of 1 mm or less...thickness,rather than inherent properties of the material, is the most important factor relating to the load Fracture-proof in dimensions of 1 mm or less required to initiate radial fractures. Can Material Properties Predict Survival of All-Ceramic Posterior Crowns? Thick & weak...thickness,rather than inherent properties of the material, is the most important factor relating to the load required to initiate radial fractures. Can Material Properties Predict Survival of All-Ceramic Posterior Crowns? Rekow, D., Zhang, Y., Thompson, V. Compendium, July, 27 Rekow, D., Zhang, Y., Thompson, V. Compendium, July, 27 As the thickness of the ceramic increases, the load required to initiate fracture increases dramatically, as indicated by this term appearing as the square of the thickness. 18 year post-op Hand-stacked feldspathic is more fracture resistant than thin & strong 36-4 MPa Feldspathic MPa Load to radial crack (N) Effect of ceramic thickness on load to failure 229 N 343 N.5 mm 1. mm 1.5 mm Ceramic thickness 64 N Effect of occlusal contact size on interfacial stresses and failure of bonded ceramic: FEA and monotonic loading analyses Yi, Yang-Jin, Kelly, J.Robert Dental Materials, 28 Proven Principles Good science happens slowly! With ceramic materials, the clinical (in-vivo) performance is routinely inferior to laboratory (in-vitro) results With bonding procedures, clinical (in-vivo) performance is routinely inferior to laboratory (in-vitro) results Sliding contacts dramatically accelerate fatigue Monolithic is more fracture resistant than layered With ceramic materials, thickness is more important than material properties Properties of the ideal C & B material Wear resistance equivalent to or lower than enamel Gold Resin Gold Fracture-proof in dimensions of Gold 1 mm or less Predictably Bondable-Conservative preparation Etch-able Ceramics Wear resistance equivalent to or lower than enamel Quantitative in vivo wear of human enamel Lambrechts, et al., j Dent Res, 1989 Ideally, a restoration should have a wear resistance similar to that of enamel. Wear resistance equivalent to or lower than enamel Each of these is critical, but WEAR RESISTANCE is perhaps the most important material property NOT material hardness NOT material abrasiveness NOT material roughness NOT material fracture resistance NOT the coefficient of friction Wear resistance equivalent to or lower than enamel Each of these is critical, but WEAR RESISTANCE is perhaps the most important material property Does a material that will not wear TOTAL WEAR RESISTANCE!!

6 Wear resistance equivalent to or lower than enamel Each of these is critical, but WEAR RESISTANCE is perhaps the most important material property Does a material that will not wear dangerously reduce our ability to adapt to dangerously CHANGES IN reduce THE STOMATOGNATHIC our ability to adapt SYSTEM? to CHANGES IN THE STOMATOGNATHIC SYSTEM? CHANGES IN THE STOMATOGNATHIC SYSTEM? HOW DO WE FREQUENTLY SEE THE SYSTEM CHANGE? Changes in occlusion related to changes in the TMJ dangerously Changes in reduce occlusion our ability related to adapt to to CHANGES IN THE STOMATOGNATHIC SYSTEM? Tooth Wear or Tooth Migration (Attrition, Erosion, Abrasion, or fracture) dangerously reduce our ability to adapt to CHANGES IN THE STOMATOGNATHIC SYSTEM? Avoiding System Failure Condylar Inclination Path of Rotating Condyle Near Misses Near Misses Angle of disclusion CHANGES IN THE STOMATOGNATHIC SYSTEM? Changes in occlusion related to changes in the TMJ Changes in occlusion related to Tooth Wear CHANGES IN THE STOMATOGNATHIC SYSTEM? Changes in occlusion related to changes in the TMJ Estimated to occur in 1/3 of our patients, irrespective of symptoms The System Normal-27 year old Current Original Current Original Normal-27 year old Degenerative-29 year old Normal-27 year old Degenerative-29 year old Normal-27 year old Degenerative-29 year old

7 Non-Adaptive Non-Adaptive Rapid Joint Degeneration Adaptive Piper M, Piper Level 1 Manual: Comprehensive TMJ Science Piper M, Piper Level 1 Manual: Comprehensive TMJ Science Anterior Open Bite Decrease in the Fossa-Ramus VD Tooth/Restoration wear Joint Degeneration Anterior Open Bite Tooth/Restoration Increase in the fracture Anterior VDO Slow Joint posterior tooth Increase in the Degeneration intrusion/migration Anterior Facial VD Anterior tooth Supraeruption } } Image courtesy of Dr. Drew Swenda Adaptive Pt. Adaptive Pt. Adaptive Pt. Patient s Concerns Splaying of Max. Anteriors......with diastemas Reverse smile line Wear on lingual of anteriors Extrusion of mand. anteriors Adaptive Pt. Adaptive Pt. Adaptive Pt. #1 Patient s Concerns Splaying of Max. Anteriors... Almost no wear on premolars Minimal wear on molars Extremely short clinical crowns - second molars Wear on lingual of anteriors

8 Adaptive Pt. #1 Adaptive Pt. #1 Avoiding System Failure Adaptive Piper M, Piper Level 1 Manual: Comprehensive TMJ Science Non-Adaptive How did this pt. adapt? Intrusion of posterior teeth Migration of anterior teeth Wear of anterior teeth Question?? What would happen if these were restored with implants? What would happen if these were restored with a material that will not wear? Piper M, Piper Level 1 Manual: Comprehensive TMJ Science Terminal teeth take a beating! Terminal teeth take a beating! Dr. Jack Turbyfill With second molars I give my patients two choices... they can choose gold or find another dentist! CHANGES IN THE STOMATOGNATHIC SYSTEM? Changes in occlusion related to changes in the TMJ Changes in occlusion related to Tooth Wear CHANGES IN THE STOMATOGNATHIC SYSTEM? Changes in occlusion related to Tooth Wear Quantitative in vivo wear of human enamel Lambrechts, et al., j Dent Res, 1989 Quantitative in vivo wear of human enamel Lambrechts, et al., j Dent Res, Subjects (18-23 years old) Complete dentitions Lambr Occlusal contacts and tooth wear All restorative procedures accomplished prior to study Woda, et al, JPD, 1979 Occlusal tooth wear in the general population of Germany: Effects of Age, Sex, and Location of Teeth Enamel loss evaluated with measuring stereomicroscope Accurate to within 1µm Schierz O, et al. Journal of Prosthetic Dentistry, Sept., 214

9 Quantitative in vivo wear of human enamel Quantitative in vivo wear of human enamel Quantitative in vivo wear of human enamel Lambrechts, et al., j Dent Res, 1989 Lambr Lambrechts, et al., j Dent Res, 1989 Lambr Lambrechts, et al., j Dent Res, 1989 Wear data must be doubled since it occurs in both arches Wear in heavy bruxers is as much as 4-5 µm per year! The Degree to Which Dental Attrition in Modern Society is a Function of Age and of Canine Contact Seligman D, Pullinger A, Journal of Orofacial Pain, 1995 Dental wear is a general physiological phenomenon found in every civilization at every age Premolars (n=48) Molars (n=49) 153 µm SD=8 µm 88 µm SD=73 µm Premolars (n=48) Molars (n=49) 153 µm SD=8 µm 88 µm SD=73 µm The wear of a dental restoration must always be related to the stomatognathic system in which the restoration has to. Ideally, a restoration should have a wear resistance similar to that of enamel months 18 months 36 months 6 months 18 months 36 months Occlusal contacts and tooth wear Woda, et al, JPD, 1979 Occlusal contacts and tooth wear Woda, et al, JPD, 1979 Occlusal tooth wear in the general population of Germany: Effects of Age, Sex, and Location of Teeth 22 Subjects (18-5 years old) All of the teeth (except the lateral incisors) displayed facets Schierz O, et al. Journal of Prosthetic Dentistry, Sept., 214 Complete dentitions Working-side wear facets were found in all posterior teeth. Age was the only inclusion criterion The presence of tooth wear was found to be largely located in the anterior teeth, which agreed with the findings from NO caries, periodontal disease, bruxism, TMD, restorations, or history of occlusal or orthodontic therapy. Class I molar relationship with good tooth alignment and minimal wear...nonworking facets were found in all first and second molars, in 82% of second premolars, and in 58% of first premolars. Occlusion with canine protection evolves toward a group type after canine wear. 836 Subjects (2-59 years old) several other studies. This guidance pattern (anterior guidance) often changes to group Impressions were made and wear evaluated

10 Occlusal contacts and tooth wear Woda, et al, JPD, Maxillary Canine Wear the introduction of metallic or ceramic prosthetic surfaces [which are more wear resistant than enamel] will prevent normal abrasion and will counteract physiologic changes of the dentition s surface. the introduction of metallic or ceramic prosthetic surfaces [which are more wear resistant than enamel] will prevent normal abrasion and will counteract physiologic changes of the dentition s surface. Proven Principles All-ceramic Options What will happen if tooth attrition is more rapid than restoration wear? Wear is going to occur in all of our patients Anterior guidance moves toward group is most patients When we use a material more wear resistant than enamel some other part of the system will likely suffer The Stomatognathic system is constantly changing! Now Let s Talk About Specific Ceramic Materials What will happen if restorations wear at different rates? All-ceramic Options High Strength Cores Bonded Ceramics Zirconia core 9-12 MPa Monolithic Zirconia Alumina core 35-6 MPa Feldspathic veneers MPa Leucite reinforced MPa 36-4 MPa All-ceramic Options High Strength Cores Bonded Ceramics Zirconia core 9-12 MPa Monolithic Zirconia Alumina core 35-6 MPa Feldspathic veneers MPa Leucite reinforced MPa 36-4 MPa Distribution of restoration types produced by Glidewell Laboratories in December 213 Anterior Posterior Lithium Disilicate 44% 14% BruxZir Solid Zirconia 31% 59% Clinical Zirconia 15% 3% Porcelain Fused to Metal 1% 1% Full Cast % 3% DiTolla M, Dental Number of Units per Month Growth of BruxZir Restorations Glidewell Dental Laboratory

11 Enamel Abrasion Enamel Abrasion Enamel Abrasion Zirconia unpolished/glazed Material loss in microns Enamel Zirconia polished Material loss in microns 9 1% of the enamel samples opposing monolithic 6 zirconia developed cracks! Obviously, sliding of the enamel antagonists on 3 Enamel a hard zirconia surface caused added cracks of the Zirconia enamel. polished Material loss in microns Enamel Zirconia polished 2, 6, 1,2, Chewing cycles Two-body wear of monolithic, veneered and glazed zirconia and their corresponding enamel antagonists Stawarczyk B, et al. Acta Odont Scand, 213 2, 6, 1,2, Chewing cycles Two-body wear of monolithic, veneered and glazed zirconia and their corresponding enamel antagonists Stawarczyk B, et al. Acta Odont Scand, 213 2, 6, 1,2, Chewing cycles Two-body wear of monolithic, veneered and glazed zirconia and their corresponding enamel antagonists Stawarczyk B, et al. Acta Odont Scand, 213 Three-body wear potential of dental yttriumstabilized zirconia ceramic after grinding, polishing, and glazing treatments Amer R, et al, Jpd, November, 214 The glazed ceramic surfaces caused more wear on antagonist enamel specimens than the rough or smooth specimens. The material that caused the least amount of wear on opposing enamel was lithium disilicate ceramic (e.max). Ideally, a restoration should have a wear resistance similar to that of enamel. Material loss in microns Ideally, a restoration should have a wear resistance similar to that of enamel. Material Abrasion...none of the tested zirconia ceramics showed 6 any wear after the simulation tests Zirconia Does Not Wear! 2, 6, 1,2, Chewing cycles Enamel Zirconia polished Two-body wear of monolithic, veneered and glazed zirconia and their corresponding enamel antagonists Stawarczyk B, et al. Acta Odont Scand, 213 Total Wear Resistance Ideally, a restoration should have a wear resistance similar to that of enamel. Antogonist (Steatite) Ceramic Material Wear depth µm Zeno Zr-Bridge. Lava. Digizon. Ceramill Zi-T-YTZP. Cercon Base. Vita Omega 9 Cercon Ceram Kiss Creation Zi-F Lava Ceram ± ± ± ± Enamel ± Which material has a wear resistance most similar to enamel? Wear performance of substructure ceramics and veneering porcelains Preis V, et al, Dental Materials, 211 Tetragonal Zirconia?? Transformation Toughening Stress induced crack propagation Increase in volume Increase in roughness Decrease in strength Monoclinic

12 Zirconia?? Transformation Toughening Zirconia?? Transformation Toughening Zirconia?? Transformation Toughening Tetragonal Stress induced crack propagation Low Temperature Degradation (LTD) Monoclinic Tetragonal Stress induced crack propagation Low Temperature Degradation (LTD) Monoclinic Tetragonal Stress induced crack propagation Low Temperature Degradation (LTD) Monoclinic Increase in volume Increase in roughness Decrease in strength 6, zirconia femoral heads placed assuming that transformation was irrelevant In 21 several hundred premature hip prosthesis failures were reported What future for zirconia as a biomaterial? Chevalier J, J Biomaterials, 26...because the material (zirconia in dentistry) can be expected to be as susceptible to LTD as in orthopedic applications...the durability of these dental devices is expected to be no less of an issue for their manufacturers. The Tetragonal-Monclinic Transformation in Zirconia: Lessons Learned and Future Trends Chevalier J & Gremillard L, J American Ceramic Society, 29 Material loss in microns Enamel Abrasion 2, 6, 1,2, Chewing cycles Zirconia unpolished/glazed Enamel Zirconia polished Two-body wear of monolithic, veneered and glazed zirconia and their corresponding enamel antagonists Stawarczyk B, et al. Acta Odont Scand, 213 Tetragonal Zirconia?? Transformation Toughening Stress induced crack propagation Low Temperature Degradation (LTD) Monoclinic Low Temperature Degradation (LTD) is defined as the spontaneous tetragonal to monoclinic transformation occurring over time at low temperatures... Two-body wear of monolithic, veneered and glazed zirconia and their corresponding enamel antagonists Stawarczyk B, et al. Acta Odont Scand, 213 Tetragonal Zirconia?? Transformation Toughening Stress induced crack propagation Low Temperature Degradation (LTD) Monoclinic Under hydrothermal changes, an undesired phase transformation from tetragonal phase to the weaker monoclinic zirconia can occur on the surface of the monolithic zirconia FDPs (fixed dental prosthesis). This is combined with an increase in the surface roughness, resulting possibly in high abrasion of the antagonist enamel. Two-body wear of monolithic, veneered and glazed zirconia and their corresponding enamel antagonists Stawarczyk B, et al. Acta Odont Scand, 213 Zirconia?? Transformation Toughening Zirconia?? Transformation Toughening Zirconia?? Transformation Toughening Tetragonal Stress Low Temperature induced crack Degradation propagation (LTD) Monoclinic Tetragonal Stress Low Temperature induced crack Degradation propagation (LTD) Monoclinic Tetragonal Stress Low Temperature induced crack Degradation propagation (LTD) Monoclinic...transformation also occurs in the presence of hydrothermal stress such as water, blood, and synovial fluids over a long period of time and is considered unfavorable because the excess volume is not compensated by crack space and causes micro and macro-cracking, reducing the mechanical properties. Low Temperature Degradation (LTD) is responsible for grain push-out, increased surface roughening, increased wear, decreased hardness, and loss of strength (2% decrease in fracture strength), which may lead to performance deterioration. The LTD treatment of dental zirconia specimens...induced a tetragonalto-monoclinic transformation (and) a significant increase of surface roughness from 12µ to 22µ... Influence of Low-Temperature Environmental Exposure on the Mechanical Properties and Structural Stability of Dental Zirconia Alghazzawi T, et al. Journal of Prosthodontics, 212 Influence of Low-Temperature Environmental Exposure on the Mechanical Properties and Structural Stability of Dental Zirconia Alghazzawi T, et al. Journal of Prosthodontics, 212 Influence of Low-Temperature Environmental Exposure on the Mechanical Properties and Structural Stability of Dental Zirconia Alghazzawi T, et al. Journal of Prosthodontics, 212

13 Surface wear Tooth Fracture Surface wear Tooth Fracture Monolithic Zirconia REMEMBER!!! Zirconia will not Break Zirconia will not wear Sacrificial Device Part of a system that is intentionally engineered to fail under excess stress. The sacrificial part is engineered to fail first, and thus protect other parts of the system. How the System Adapts to Change The System s Sacrificial Devices Change in occluding surfaces Surface wear Tooth Fracture Zirconia may aggressively wear opposing surfaces if not carefully adjusted & polished Zirconia may become rougher with and LTD Fuses Circuit Breakers GFI Switches (Ground Fault Interrupters) Periodontal Response Mobility Tooth Migration Tooth Intrusion Neuromuscular Adaptation Neuromuscular Disharmony Occlusal Disharmony How the System Adapts to Change Change in occluding surfaces Surface wear Tooth Fracture Surface wear Techscan Indicates that Initial Contact & most of the Occlusal Force is on #15 Tooth Fracture Techscan-214 Periodontal Response Muscle Pain- Approximately 1 year Techscan Indicates that Initial Contact & most of the Occlusal Force is on #15 Mobility Tooth Migration Tooth Intrusion What may happen if this is monolithic zirconia? Monolithic Zirconia Restoration Placed on #15 in Dec. 212 The Patient is a Dentist! Patient Identifies #15 as the Restoration is First Point of Contact Replaced & Patient is Asymptomatic 1 year, 9 months in Dec it s night and day the change after getting that thing off. 76.1% 23.9% 212 One Set From Immediately After Restoration Delivery Techscan One Set From Immediately After Restoration Delivery The Patient Provided Two Sets of Study Casts 214 One Set From Two Years Post-Op Just prior to replacement 214 One Set From Two Years Post-Op

14 How the System Adapts to Change Change in occluding surfaces Surface wear Tooth Fracture Periodontal Response Mobility Tooth Migration Tooth Intrusion What may happen if these are both monolithic zirconia with implants? How the System Adapts to Change Change in occluding surfaces Surface wear Tooth Fracture Periodontal Response Implant Failure! Mobility Tooth Migration Tooth Intrusion } Neuromuscular Adaptation Neuromuscular Disharmony System Failure! Occlusal Disharmony Monolithic Zirconia REMEMBER!!! Zirconia will not Break Zirconia will not wear Zirconia may aggressively wear opposing surfaces if not carefully adjusted & polished Zirconia may become rougher with and LTD

15 Monolithic Zirconia REMEMBER!!! Zirconia will not Break The Zirconia System will is constantly not wear changing Zirconia may aggressively wear opposing surfaces if not carefully adjusted & polished Zirconia demonstrates Zirconia no adaptive may become capacity rougher with and LTD All-ceramic or metal-ceramic tooth supported fixed dental prostheses (FDPs)? A systematic review of the survival and complication rates. Part I S: Single crowns (SCs) Sailer I, et al, Dental Materials, 215 Zirconia based crowns exhibited significantly more loss of retention than metal-ceramic crowns. Zirconia based crowns exhibited significantly more loss of retention than metal-ceramic crowns. Zirconia-based restorations require preparations with significant retention and resistance form! All-ceramic or metal-ceramic tooth supported fixed dental prostheses (FDPs)? A systematic review of the survival and complication rates. Part I S: Single crowns (SCs) Crowns made out of densely sintered zirconia cannot be recommended as a primary treatment option, due to an increased risk of chipping of the veneering ceramic and loss of retention. Sailer I, et al, Dental Materials, 215 Zirconia based crowns exhibited significantly more loss of retention than metal-ceramic crowns. Can & should zirconia be bonded? Crowns made out of densely sintered zirconia cannot be recommended as a primary treatment option, due to an increased risk of chipping of the veneering ceramic and loss of retention. Means & SD in MPa Means & SD in MPa JPD, May 211 Primer RelyX Unicem Panavia Alloy Primer Totalbond Control Metal Primer II Metaltite 15.9 (6.2) 7.8 (5.2) 7.2 (3.2) 6.2 (3.2) 3.6 (5.5) 11.2 (7.9) 8.2 (6.5) 8.8 (5.1) 9. (5.9) 6.6 (5.6) MDT (1-methacryloyloxydecyl dihydrogen phosphate) RelyX Unicem Panavia Initial 15.9 (6.2) 11.2 (7.9) 48 Hours 15 Days 1.2 (6.5) 6.1 (5.3) 13.9 (4.4) 3.6 (2.2) Reductions in bond strength up to 87% for Panavia and 66% with RelyX Unicem were observed after 5 months of water storage. Fatigue Behavior of the Resinous Cement to Zirconia Bond Seto K, McLaren E, Caputo A, & White S: Journal of Prosthodontics, 213

16 Glidewell Dental Laboratory Glidewell Dental Laboratory Most restorations require replacementtherefore retrievability should be a consideration If we could bond zirconia, should we? Retrievability? Most restorations require replacementtherefore retrievability Retrievability? should be a consideration In the next 5-7 years we will have 6, zirconia restorations to cut off PER MONTH! Number of Units per Month Growth of BruxZir Restorations Glidewell Dental Laboratory Proven Principles Restorations Failtherefore, we should consider retrievability Restoration fracture is not the worst mode of failure The system is constantly changing The system is constantly ADAPTING! Our restorations should also adapt When we use a material more wear resistant than enamel some other part of the system will likely suffer Proven Principles The activity that caused the change in the system will almost always continue Is the best answer really a more wear resistant material? The activity that caused the change in the system will almost always continue Is the best answer really a more wear resistant material? The activity that caused the change in the system will almost always continue Is the best answer really a more wear resistant material? The activity that caused the change in the system will almost always continue Is the best answer really a more wear resistant material? All-ceramic Options High Strength Cores Zirconia core 9-12 MPa Monolithic Zirconia Alumina core 35-6 MPa When a patient generates enough occlusal force to break a PFM, a BruxZir is a great choice as a replacement. My Opinion A patient that is a bruxer, has significant wear, or has destroyed other restorations is the last patient in which these restorations should be placed. Bonded Ceramics Feldspathic veneers MPa Leucite reinforced MPa 36-4 MPa

17 All-ceramic Options High Strength Cores Bonded Ceramics Zirconia core 9-12 MPa Monolithic Zirconia Alumina core 35-6 MPa Feldspathic veneers MPa Leucite reinforced MPa 36-4 MPa Conservative Bonded vs. Cemented Full Coverage Why Consider Bonded Ceramic Restorations? Conservative Bonded vs. Cemented Full Coverage Only Bonded All-Ceramics satisfy all of the indications! All-Ceramic Restorations Maximum Esthetics Conservation of tooth structure Economics/Efficiency Metal-free restorations Bonded All-Ceramic Bonded All-Ceramic All-Ceramic All-Ceramic Conservative Bonded vs. Cemented Full Coverage The failure mode of veneers is different than the failure mode for full coverage crowns. With veneers we put the risk in the restoration, not the tooth. John Kois Conservative Bonded vs. Cemented Full Coverage One of the most important factors in determining the longevity of the tooth/restoration complex is the amount of remaining tooth structure. Terry Donavan 9 Year post-op Maxillary anterior teeth derive most of their strength from the lingual tooth structure Natural enamel contacts are the most accurate, most durable, & kindest to opposing tooth structure 9 Year post-op Conservative Bonded vs. Cemented Full Coverage One of the most important factors in determining the longevity of the tooth/restoration complex is the amount of remaining tooth structure. Terry Donavan Conservative Bonded vs. Cemented Full Coverage One of the most important factors in determining the longevity of the tooth/restoration complex is the amount of remaining tooth structure. Terry Donavan Posterior supragingival finish lines... avoid pulpal encroachment... Simplify preparations and impressions... allow for more predictable bonding & are often more esthetic Posterior supragingival finish lines... avoid pulpal encroachment... Simplify preparations and impressions... allow for more predictable bonding & are often more esthetic

18 Conservative Bonded vs. Cemented Full Coverage One of the most important factors in determining the longevity of the tooth/restoration complex is the amount of remaining tooth structure. Terry Donavan The failure mode of veneers is different than the failure mode for full coverage crowns. With veneers we put the risk in the restoration, not the tooth. High Strength Lithium Disilicate e.max CAD-36 MPa e.max Press-4 MPa Layered Zirconia Core Crowns Sliding Fatigue in Water Metal-Ceramic Crowns Lithium Disilicate (monolithic) NYU Fatigue Research 1K failure >3K 1mil. or less failures John Kois The take-home 36-4 MPa damage to intaglio surface significantly weakens Steam Clean, Ultra-sonic, or carefully air abrade with glass beads! The take-home 36-4 MPa damage to intaglio surface significantly weakens Steam Clean, Ultra-sonic, or carefully air abrade with glass beads! Adjust with light pressure, keep wet & cool Zirconia Core e.max Restorations Adjust with light pressure, keep wet & cool Photograph, courtesy of Bill Connell, CDT e.max (lithium disilicate) wears opposing enamel less than Empress (leucite reinforced) e.max (lithium disilicate) wears when opposing enamel For clinical success, the quality of the technician is more important than the material. Dr. John Sorenson Southwest Academy of Restorative Dentistry Dallas, TX, January 17, Enamel Volume Loss-Two Body Wear e.max CAD IPS Empress CAD Lava Ultimate University of Minnesota Material Volume Loss opposing enamel e.max CAD IPS Empress CAD Lava Ultimate Zirconia Zirconia has total wear resistance-zero Wear 3K 15N fully hydrated University of Minnesota Two-body wear of monolithic, veneered and glazed zirconia and their corresponding enamel antagonists Stawarczyk B, et al. Acta Odont Scand, 213

19 Prep retention and resistance The bond to etched lithium disilicate is significantly stronger than the bond with leucite reinforced materials. Bona, A. D., et. al. J Adhesive Dent, 2 Should e.max be bonded? Prep retention and resistance... Should e.max be bonded? A relatively thin layer (1 microns) of resin luting agent bonded to both IPS Empress and IPS Empress 2 significantly increased the characteristic strength of the ceramics. Pagniano, R. P., Jr., et. al. JPD, May, 25 The evidence The evidence Prep retention and resistance... Should e.max be bonded?...the disruption of the bond at either interface results in a reduced ability of the ceramic to support a vertical load. Clelland, N. L., et. al. JPD, January, 27 Prep retention and resistance... Should e.max be bonded? disruption of the ceramic-cement interface had a more detrimental effect on the load-bearing capacity of the simulated restoration than the disruption of the cement-dentin interface. Clelland, N. L., et. al. JPD, January, 27 Prep retention and resistance... Should e.max be bonded? For maximum strength Ceramics that can be etched should be bonded With tooth preparations that have adequate reduction (restoration thickness), retention form, and/or compromised ability to isolate - Cementation with Resin Modified Glass Ionomer may be the preferred choice The evidence The evidence The Bottom line reinforced restorations 36-4 MPa Fixed Partial Dentures with e.max???? reinforced restorations 36-4 MPa Fixed Partial Dentures with e.max???? Fixed Partial Dentures with e.max???? Survival rate of lithium disilicate restorations at 4 years: A retrospective study Sulaiman,Delgado,Donovan, JPD, ,34 restorations - 15,82 monolithic & 5538 layered Data collected for 45 months from two commercial Dental Laboratory s database systems Layered Single unit crowns fractured at approximately twice the rate of monolithic crowns, but the fracture rate was still low. (1.83% vs.91%) The failure rate for FPD s (all monolithic) was 4.55% or almost 4 times that of single units

20 Fixed Partial Dentures with e.max???? Clinical outcomes of lithium disilicate single crowns and partial fixed dental prostheses: A systematic review Pierre S, et al, JPD, 214 Single Units - Short term evidence (5 years) % survival Single Units - Medium term evidence (5-1 years) % survival Most For single FPD s short crowns term failed (1-5 in years) the - posterior 78.1% survival region For FPD s medium term (5-1 years) 7.9% survival Fixed Partial Dentures with e.max???? The Take-Home Single unit lithium disilicate restorations have an acceptable survival rate, particularly in the anterior region Fixed Partial Dentures should be used with extreme caution in the anterior region only Fixed Partial Dentures with e.max???? Survival rate of lithium disilicate restorations at 4 years: A retrospective study Sulaiman,Delgado,Donovan, JPD, ,34 restorations - 15,82 monolithic & 5538 layered Data collected for 45 months from two commercial Dental Laboratory s database systems Layered Single unit crowns fractured at approximately twice the rate of monolithic crowns, but the fracture rate was still low. (1.83% vs.91%) The failure rate for FPD s (all monolithic) was 4.55% or almost 4 times that of single units Layered Single unit crowns fractured at approximately twice the rate of monolithic crowns, but the fracture rate was still low. (1.83% vs.91%) Layered Single unit crowns fractured at approximately twice the rate of monolithic crowns, but the fracture rate was still low. (1.83% vs.91%) Indications for Monolithic Indications for Layered The take-home reinforced restorations 36-4 MPa Layered All-Ceramics are more susceptible to fracture than Monolithic Ceramics Posteriors Maxillary Anteriors The strongest BCR available today Suitable for all single unit restorations, veneer thru full coverage Current studies, both in-vitro and in-vivo report excellent durability with single unit restorations Monolithic or layered in a variety of translucencies Widely available, familiar fabrication technique Mandibular Anteriors The take-home reinforced restorations 36-4 MPa Micro-layered Lithium Disilicate Micro-layered Lithium Disilicate Ideal for preps with compromised retention Prep shade communication critical Aesthetics improving with additional translucencies, currently a new multi-layer ingot For maximum strength e.max should be etched and bonded Case provided by Dr. J. A. Reynolds Ceramist, Matt Roberts

21 Micro-layered Lithium Disilicate Layered Lithium Disilicate Layered Lithium Disilicate If your patient presents with evidence of bruxism including wear of the canines and exposed dentin in the molars, which of the following would be indicated if you had to restore the occlusal surface of the mandibular second molars? a. a gold crown b.a monolithic alumina restoration c. a monolithic zirconia restoration d.any of the above Answers a If your patient presents with evidence of bruxism including wear of the canines and exposed dentin in the molars, which of the following would be indicated if you had to restore the occlusal surface of the mandibular second molars? a. a gold crown b.a monolithic alumina restoration c. a monolithic zirconia restoration d.any of the above Which of the following is true of monolithic zirconia restorations? a. monolithic zirconia restoration wear excessively b. monolithic zirconia restorations tend to discolor c. monolithic zirconia restorations require preparations with signi icant retention d. monolithic zirconia restorations often fracture c Which of the following is true of monolithic zirconia restorations? a. monolithic zirconia restoration wear excessively b. monolithic zirconia restorations tend to discolor c. monolithic zirconia restorations require preparations with signi icant retention d. monolithic zirconia restorations often fracture Which of the following does not occur on the surface of a monolithic zirconia restoration after transformation toughening? a. The surface becomes smoother b. The surface becomes rougher c. The surface becomes weaker d. A & C above a Which of the following does not occur on the surface of a monolithic zirconia restoration after transformation toughening? a. The surface becomes smoother b. The surface becomes rougher c. The surface becomes weaker d. A & C above When a stress induced crack starts to spread through zirconia which of the following occurs? a. transformation toughening - a transformation from monoclinic to tetragonal crystalline structure b. low temperature degradation c. transformation toughening - a transformation from tetragonal to monoclinic crystalline structure d. catastrophic failure of the material c When a stress induced crack starts to spread through zirconia which of the following occurs? a. transformation toughening - a transformation from monoclinic to tetragonal crystalline structure b. low temperature degradation c. transformation toughening - a transformation from tetragonal to monoclinic crystalline structure d. catastrophic failure of the material Which of the following ceramic materials has the lowest fracture strength? a. Zirconia b. Feldspathic porcelain c. d. Leucite b Which of the following ceramic materials has the lowest fracture strength? a. Zirconia b. Feldspathic porcelain c. d. Leucite