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Esthetic implant therapy can be challenging in the anterior maxilla, and meticulous treatment is often required to deliver optimal esthetics. Close collaboration between surgical and prosthetic team members using the novel approach of prosthetic crown lengthening helped camouflage a shallow implant platform location, providing the proper gingival frame for esthetic restorations. This case report presents an interdisciplinary approach that included ridge augmentation, second-stage crown lengthening, and prosthetic soft tissue manipulation to address an implant placed too shallow in the alveolus of an extraction socket. [ABSTRACT FROM AUTHOR]

The article focuses on dental implant-supported zirconia full-mouth rehabilitations have become a treatment option for patients with failing dentitions or edentulism. It mentions fabricating metal-ceramic or metal-acrylic restorations and number and position of implants and guided surgery and loading protocol and zirconia full-mouth restorations with reduced risk of chipping and fractures. It also mentions principles of porcelain-fused-to-metal and porcelain-fused-to-zirconia restorations.

The article focuses on the use of high-strength all-ceramic restorations in the rehabilitation of a patient with a severely worn dentition caused by dental attrition and compromised by dental caries. Topics include etiology and diagnosis of worn dentition, treatment plan, and esthetic evaluation. The use of monolithic zirconia for the definitive restorations and fabrication planned is also mentioned.

The article describes the case of a patient who underwent esthetic and functional rehabilitation of the severely worn dentition. It discusses the patient's medical history, the objectives of the full-mouth rehabilitation, determination of incisal edge position, and surgical guide fabrication and implant placement.

Objectives: This retrospective survey assessed the clinical survival of zirconia-based crowns (PFZ) and conventional porcelain- fused-to-metal (PFM) crowns on posterior teeth in private practice. Method and Materials: A print survey of 13 private practitioners was conducted to assess the long-term survival of previously placed full-coverage crowns. The practitioners reported a total of 2,182 premolar (n = 881) and molar (n = 1,301) full-coverage single crowns, 1,102 PFZ and 1,080 PFM, fabricated by one dental laboratory (Cusp, Boston) and followed over 7.4 years. All post-cementation complications (eg, porcelain fractures and chippings) were recorded as failures. In the PFZ group, one veneering porcelain (CZR, Kuraray Noritake) was used in combination with three coping systems (Lava, 3M ESPE; Procera, Nobelbiocare; Katana, Kuraray Noritake). Kaplan-Meier survival analysis was used for statistical analyses. Results: The probability of survival of posterior crowns investigated over the period of study (7.4 years) was 99.3% for PFM and 99.2% for PFZ restorations. There was no statistically significant difference (P = .614) between PFZ and PFM groups. In the PFZ group, probability of survival was 97.7% for Lava, 100% for Procera, and 99.5% for Katana. There were no statistically significant differences (P = .34) between the three PFZ systems or the location of the crowns (premolar or molar; P = .454). Conclusion: PFZ crowns fabricated with CZR and three commercial zirconia coping systems revealed excellent long-term success rates. Survival times and survival probabilities of posterior PFZ crowns did not differ from PFM crowns and were independent of type of coping system and location (molar or premolar teeth). [ABSTRACT FROM AUTHOR]

The article focuses on the treatment of esthetic problems due to parafunction in the anterior dentition. It states that treating a displeasing smile entails the need to know its causative factor particularly in terms of wear patterns. It mentions that orthodontic therapy is useful to rebuild the proper anteroposterior position of the anterior incisors. It says that the prior to the administration of the esthetic wax-up, the he incisal edge position must first be established so that patient and clinician can decide on the wanted length. It adds that restorations involve the attachment of veeners on all anterior maxillary and mandibular teeth.

Objective: To compare in vitro the influence of 3 cementation techniques on leakage and fracture strength of alumina all-ceramic crowns after cyclic loading in an artificial chewing simulator. Method and Materials: Forty-eight extracted molars were mounted in a way that simulates natural tooth mobility. Crowns (Procera Alumina, Nobel Biocare) were fabricated and inserted with either conventional cementation with zinc phosphate cement without pretreatment (group ZOP); cementation with a universal adhesive resin cement without pretreatment (group HYB); or adhesive bonding with composite resin after pretreatment of the tooth (dentin bonding agent) and the crown (airborne-particle abrasion and a special ceramic priming agent containing adhesive monomers that bond to metal-oxide ceramics) (group ADH). All specimens were stored in artificial saliva and subjected to 1.2 million load cycles in a dual-axis chewing simulator (Willytec). Eight specimens per group were subjected to compressive load until failure, while the remaining 8 specimens were stained and sectioned for measuring of dye penetration. One-way ANOVA and Tukey HSD were used for statistical analyses (α= .05). Results: Cementation techniques were significantly different (P = .009) in regard to mean load at failure. Fracture strength was significantly greater for ADH (mean load at fracture, 2,782 ± 419 N) as compared to HYB (1,980 ± 270 N) or ZOP (1,788 ± 242 N). All groups differed significantly for leakage values (P < .001), with ADH showing the lowest mean leakage (0.04 ± 0.07 mm), followed by HYB (0.96 ± 0.16 mm) and ZOP (2.44 ± 0.19 mm). Conclusion: Cementation technique affects fracture strength and leakage of all-ceramic molar crowns. Fracture strengths were well above natural chewing forces for all cementation methods. However, adhesive bonding significantly increased fracture strength and improved marginal seal of alumina crowns. [ABSTRACT FROM AUTHOR]

Objective: To evaluate short- and long-term shear bond strengths of 4 luting agents to zirconia following different surface treatments. Method and Materials: A total of 320 ceramic specimens fabricated from a commercial zirconium oxide ceramic (Lava) were randomly divided into 4 groups: left untreated (NOT), airborne-particle abraded (SND), Rocatec tribochemical silica/silane coated (ROC), or ground and polished (GAD). Aesin composite cylinders were bonded to the zirconia specimens with resin composite luting agent RelyX ARC (ARC), universal adhesive resin composite RelyX Unicem (UNI), adhesive-phosphate- monomer-containing resin composite Panavia F (PAN), or the hybrid glass-ionomer cement RelyX Luting (LUT). Subgroups of 10 specimens were stored in distilled water (37°C) for 3 days (ST) or stored for 180 days and thermocycled for 12,000 cycles (LT/TC) before shear bond strength was tested. Statistical analyses included Kruskal-Wallis and Wilcoxon 2-sample rank sum test (a = .01). Results: Short-term shear bond strengths were higher with AOC than with SND, which were both greater than GAD or NOT. UNI revealed higher shear bond strengths than PAN, AAC, and LUT. LT/TC significantly decreased shear bond strength values. GAD and NOT produced the lowest shear bond strengths. SND and ROC significantly increased bond strength. ROC generally yielded the highest long-term shear bond strength, especially with UNI, PAN, or AAC. These were similar to SND and PAN, which revealed the highest long-term shear bond strengths. Conclusions: Surface treatment, luting agent, and storage conditions significantly influence shear bond strengths to zirconia. Artificial aging significantly reduces shear bond strengths. Airborne-particle abrasion combined with a resin composite containing adhesive phosphate monomers or tribochemical silica/silane coating combined with any of the tested resin composite luting agents provides superior long-term shear bond strength values. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to determine whether anterior crowns fabricated using a computerized shade selection system (ShadeScan, Cynovad) (experimental procedure) match adjacent teeth better than anterior crowns fabricated using conventional shade prescription and clinical slides (control). Method and Materials: Five subjects who required a crown to restore a maxillary central incisor were selected. Two metal-ceramic crowns were fabricated for each incisor, 1 using the experimental procedure and 1 using the control method. The shade selection method to be used for the first and second crowns was randomly assigned. The duration of each procedure was recorded. Each restoration was tried-in in a double-blind manner and evaluated for its level of match to adjacent teeth using modified Ryge criteria. Data were analyzed within each subject using descriptive statistics and paired t test (alpha = .05). Results: In 40% of the cases, both procedures did equally well. In the remaining 60% of the cases the control procedure (two-thirds of the cases) performed better than the experimental procedure (one-third of the cases). Duration of the control procedure was 14.4 ± 5 minutes, and the experimental procedure was 5.2 ± 3.3 minutes. A paired t test showed the difference was significant (P = .0045). Conclusion: The level of matching of crowns fabricated with the ShadeScan system was not different from crowns fabricated using the control. However, it took significantly less time to record the shade with the ShadeScan system. [ABSTRACT FROM AUTHOR]

The keys to obtaining predictable and consistent results in esthetic treatment are diagnosis, smile design, treatment planning, team communication, and understanding patient expectations. Digital technology can facilitate this important communication with the patient in order to provide them with a clear understanding of the initial clinical situation, as well as a simulation of the future restoration. The goal of minimally prepared veneers is to preserve as much enamel as possible because bonding to enamel is more predictable than bonding to dentin. This article emphasizes an interdisciplinary approach, digital workflow, minimally invasive treatment, and material selection based on a digital smile design, printing technology for prototype models, and mock-up. [ABSTRACT FROM AUTHOR]

A one-step divergent sliding post incorporated through a crown casting provides effective auxiliary retention for the short crown preparation, especially when interocclusal distance is minimal. With this procedure, retention is gained from the residual walls of both the extracoronal preparation and the canal preparation even though their respective axes may be divergent. A tube and screw attachment may also be incorporated inside an understructure coping to secure a permanently cemented short crown-and-bridge retainer. Both techniques may be used separately or in combination for maximal retention and, despite the additional complexity and cost, will compensate for the short extracoronal walls of the second molar preparation. [ABSTRACT FROM AUTHOR]

The primary objective of a provisional restoration is to promote gingival health before placement of the final restoration. A method for construction of a provisional fixed partial denture with improved marginal adaptation without the use of an indirect method is presented. A preformed shell of the provisional restoration must be fabricated from the diagnostic cast before any operative procedure attempted. The laboratory-made shells are relined intraorally to promote close adaptation to the finishing line of the preparation. A wash of cold-curing acrylic resin is applied to the margins while the bulk of the relining material is at the doughy stage. The technique provider superior results and reduced chairtime. [ABSTRACT FROM AUTHOR]

Implant-supported posterior restorations must be fabricated following established prosthodontic principles. The need for screw-retained abutments and the narrow diameter of root-form implants dictate additional treatment protocols that fall beyond the scope of conventional prosthodontics. Cemented restorations offer simplicity and good control of morphology, but can only be considered if removal or no reservicing of the restoration is anticipated. Screw-retained restorations allow for reservicing or remediation but necessitate centering of the retaining screw within the occlusal anatomy. When the implant is misaligned, axis problems are solved with preangled copings, custom copings, or double frameworks. The diameter of root-form implants is significantly smaller than posterior natural teeth, and the emergence of the restorations must be progressively flared to achieve proper morphology. Limited interocclusal space and implant placement may dictate restoring posterior teeth as premolars, selecting a short abutment or a nonsegmented ("UCLA") abutment, or overlapping the crowns over the soft tissues. The final abutment selection is best assisted with a diagnostic waxing and with provisional restorations anticipating the completed treatment. [ABSTRACT FROM AUTHOR]

The article focuses on a study which examined the prosthetic restoration of hydroxylapatite-coated titanium dental Integral implants. The study included 772 implants that were placed between 1982 and 1989. Selection of patients for the study included various procedures such as general health examination, psychological evaluation, oral hygiene status and radiographic survey. For the construction of implant crown restoration, cemented prosthesis and screw-retained prosthesis were considered. The study concluded that the fabrication of fixed partial dentures for Integral implants depends on various assortment of abutment configurations.

Abstract: Objective: New technique describes an alternative treatment modality of making direct provisional restoration. Clinical considerations: A preoperative wax‐up should be fabricated, followed by fabrication of a transparent polyvinyl siloxane (VPS) matrix in a clear plastic prefabricated tray with retentive holes. After the tray is separated from the model, two additional holes will be made through the tray and the VPS for injecting and venting of the temporary resin. After the teeth are prepared and the separating medium applied to them, the resin should be injected into the entrance hole using the provided auto‐mix cartilage tip. The flow of the resin around the preparation can be observed through the clear mold and once the resin starts to extrude from the exit hole. It is necessary to block the exit hole with a finger while continuing to inject. This will increase the pressure inside the mold and improve marginal adaptation. Before complete polymerization, the matrix is removed. The provisional restorations are removed from the matrix and contoured, adjusted, and polished. Conclusion: This technique will help the clinicians to enhance the quality of the provisional restorations, to prevent entrapment of bubbles, improve marginal precision and prevent seating error. CLINICAL SIGNIFICANCE: This study described a novel technique for constructing a direct provisional restoration by injecting bis‐acryl temporary resin into a matrix that is already seated over the prepared tooth. [ABSTRACT FROM AUTHOR]

Shade matching is an essential aspect of restorative and esthetic dentistry. Despite the development of reliable dental technologies over the years, matching restorations to natural teeth is still one of the most challenging tasks for dental technicians and clinicians. This article offers a step-by-step approach for a more predictable and enhanced outcome for shade-matching cases with all-ceramic materials. Four case reports utilizing various tools and techniques are included. [ABSTRACT FROM AUTHOR]

Purpose:This study evaluated and compared the effect of different ceramic primers on the shear bond strength of RMGIC to zirconia with and without air-particle abrasion.Material and Methods:120 zirconia square specimens (5 mm × 5 mm × 2 mm) were fabricated. Half of the specimens were air-particle abraded (A) and the other half were left untreated (NA). Both groups were further divided into six subgroups (n = 10). Composite cylinders (2.9 mm × 3.0 mm) were fabricated and bonded to the zirconia samples with RMGIC (RelyX Plus) after different priming methods: no ceramic primer (group NS); Z-Prime (group ZP); Clearfil ceramic primer (group CP); cleaned with Ivoclean then Monobond plus (IV/MS); Monobond plus (group MS); and Rely X ceramic primer (group RX). Specimens were rinsed, stored in distilled water, and thermocycled (TC) for 10,000 cycles between 5 and 60 °C with a dwell time of 15s. Data were analyzed with two-way ANOVA and the Tukey–Kramer method test (a = .05).Results:air-particle abrasion significantly affected bond strength of RMGIC to zirconia regardless of the primer used (p < 0.001 for all primers and the control). After TC, A-ZP (11.1 ± 0.6 MPa), A-CP (11.9 ± 0.6 MPa), and A-MS (11.9 ± 0.5 MPa) revealed the highest shear bond strength values, while NA-NS (2.9 ± 0.3 MPa) and NA-RX (4.7 ± 0.5 MPa) had the lowest. Failure modes were primarily adhesive.Conclusion:air-particle abrasion with aluminum oxide and application of MDP-based ceramic primers provide the highest bond strength of RMGIC to zirconia. [ABSTRACT FROM AUTHOR]

Dentition that is worn from attrition or erosion presents many challenges. A comprehensive extraoral and intraoral examination should be performed to collect necessary data to create a treatment plan. This article covers key intraoral parameters when dealing with these complex cases. The case discussed illustrates an interdisciplinary plan to serve the patient's needs and expectations, and provide biological and functional support for the final restorations. [ABSTRACT FROM AUTHOR]

Ultimate restorative success always begins with an accurate diagnosis and a carefully designed treatment plan, which often mandates an interdisciplinary approach. The goal of minimally prepared veneers is to preserve as much enamel as possible, because bonding to enamel is more predictable than bonding to dentin. Keeping the majority of the preparation in enamel has been shown to improve long-term success. This article emphasizes an interdisciplinary approach, minimally invasive treatment, and guided tooth preparations, based upon a digital smile design, a diagnostic wax-up, and a mock-up. [ABSTRACT FROM AUTHOR]

A majority of the population regards separation of the anterior teeth as esthetically displeasing. If treatment is provided without properly analyzing such gaps and identifying the cause, the spaces may reopen. This article introduces a linear protocol to effectively assess and diagnose the etiologic factors creating the separation of anterior teeth. The clinician must pinpoint the location(s) of the space, measure the amount of separation, and identify the etiologic factors. Proper analysis will also reveal whether interdisciplinary treatment is needed. As an example of this protocol, a case is presented in which there was splaying of the maxillary anterior teeth. A systematic approach was taken to effectively analyze and diagnose the cause of separation. Splint therapy was used to ensure that the condyles were fully seated. The mandibular position was recorded and reproduced with mounted casts on a semiadjustable articulator. The maxillary posterior teeth were removed from the casts to evaluate the coupling of the anterior teeth, followed by trial equilibration. The wax-up was transferred to the patient's mouth for approval and to ensure that the tooth proportions were in harmony with the face. Conservative treatment using partial and full laminate veneers was administered to close the gaps. Tooth position was maintained by rechecking the occlusion and placing a Hawley retainer in the maxilla. This linear protocol increases diagnostic efficiency and allows the clinician to successfully manage splaying in the esthetic zone. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the bond strength of recently developed feldspathic veneering ceramics to zirconium- oxide ceramic core material (Y-TZP). In addition, the effect of thermocycling on the bond strength was investigated. Methods: 90 square Lava framework Y-TZP specimens were randomly assigned to three groups (n=30) and veneered with one of the three zirconia veneering ceramics Cerabien ZR (CZR), GC Initial (Gd), or Lava Ceram (LC). 30 additional metal-ceramic specimens served as the control (VO). 15 specimens per group were stored in a saline solution for 3 days. To test the durability of the bond, 15 specimens per group were thermocycled for 10,000 cycles between 5° to 60° C with a 15-second dwell time. Shear strength was tested with an Instron universal testing system. A two-way ANOVA model and Tukey's HSD were applied for statistical analyses (α= 0.05). Results: The different material combinations revealed significantly different shear bond strength values (CZR>GCI>LC>VO). All veneering ceramic/zirconia combinations showed significantly higher bond strength than the metal-ceramic control VO. Bond strength values were not affected by thermocycling, except for CZR, which had significantly higher bond strength after thermocycling. Microscopic evaluation of failure modes revealed 100% cohesive failures in the veneering ceramic for all specimens. [ABSTRACT FROM AUTHOR]

The article presents several answers to the question of how dentists and clinicians should bond zirconia.

Purpose: Procera® Alumina crowns are widely used; however, the effect of crown margin design on marginal fit is unknown. This study measured and compared the precision of fit of Procera® Alumina crowns with two crown margin designs: all-porcelain versus alumina-supported margins. Materials and Methods: Sixteen noncarious extracted human premolars were prepared for Procera® Alumina crowns with an internally rounded shoulder preparation. Impressions were made from all teeth, and master dies were poured with type IV dental stone. The specimens were randomly divided into two groups. Procera® Alumina crowns were fabricated: eight crowns with circumferential porcelain-butt (all-porcelain) margins and eight crowns with coping (alumina-supported) margins (control). Precision of fit was measured at six points on each crown with a profilometer (profile projector). The data were statistically analyzed with an independent-samples t-test (α < 0.05). Results: The mean marginal gap size (μm) of coping margins was 68.07 ± 16.08 and of porcelain-butt margins was 101.29 ± 43.71. There was no statistically significant difference ( p= 0.065) of the marginal gap size between coping margins and porcelain-butt margins. Conclusion: The results of this study demonstrate that there was no statistically significant difference in the marginal fit of coping and porcelain-butt margins. Both margin designs are within clinically acceptable ranges. Therefore, clinicians may choose to use a coping margin, as it is less labor intensive and requires less time for fabrication, unless there is a specific high esthetic need for a porcelain-butt margin. [ABSTRACT FROM AUTHOR]

: Although metal-ceramic restorations are widely used, there is a lack of information about how the fit is affected by margin designs. : This study measured and compared the precision of fit of metal-ceramic crowns with two margin designs. : Thirty-two extracted human premolar teeth were prepared for complete-coverage restorations with an internally rounded shoulder preparation. Impressions were made from all teeth, and master dies were poured with improved stone type V. MC crowns were fabricated with a porcelain-butt margin on the buccal aspect (n = 32) and a feather-edge metal margin on the lingual aspect (n = 32), which served as a control group. Precision of fit was measured three times at the mid-buccal and mid-lingual margins of each crown with a profilometer. The data were statistically analyzed with the paired t-test (α < .05). : Mean marginal gap size of porcelain-butt margins was 27.93 μm (±15.84) and of feather-edge metal margins 42.43 μm (±24.12). The marginal gap size of feather-edge metal margins was statistically significantly greater than that of porcelain-butt margins (p = 0.0045). : The marginal fit of porcelain-butt margins was significantly better than that of feather-edge metal margins. : Porcelain-butt margins in this study had a better marginal fit than feather-edge metal margins, and thus have given clinicians evidence to prefer the use of porcelain-butt margins. [ABSTRACT FROM AUTHOR]

Background: Densely sintered aluminium oxide ceramic is a popular material for ceramic copings and all-ceramic restorations. A strong, predictable, and long-term durable resin bond is key for long-term clinical success of bonded alumina-based restorations. Purpose: The purpose of this study was to measure and compare in vitro shear bond strengths of three resin cements with and without their corresponding silane coupling/bonding agent to air particle-abraded densely sintered aluminum oxide ceramic after long-term water storage and thermocycling. Materials and Methods: Composite resin cylinders were bonded to air particle-abraded samples of densely sintered aluminum oxide ceramic with Noribond DC® (Noritake Dental Supply, Inc., Aichi, Japan), Panavia 21® EX (Kuraray, Osaka, Japan), and Variolink II® (Ivoclar Vivadent, Schaan, Liechtenstein), which were used with and without their corresponding silane coupling and bonding agents (n = 15). All specimens (N = 90) were stored for 180 days in water and subjected to repeated thermocycling for a total of 12,000 cycles before shear bond strength was tested. Data were analyzed with the KruskalWallis test and the Wilcoxon two-sample rank sum test at the 5% level of significance. Results: Most groups had no or only minimal bond strength to densely sintered alumina after simulated aging. Panavia had the highest bond strength without silane/bonding agent application. Noribond with its silane/bonding agent revealed the highest overall bond strength, which was significantly greater than that of either Variolink or Panavia after silanization. Conclusions: Resin cements revealed significantly different bond strengths, and the use of silane coupling and bonding agents had various effects on the resin bond to pure densely sintered alumina. CLINICAL SIGNIFICANCE Selection of the proper cement/bonding system is fundamental to clinical long-term success of bonded alumina-based restorations. Noribond with its bonding agent and ceramic primer seem to fulfill these requirements under clinically relevant testing conditions. [ABSTRACT FROM AUTHOR]

Presents an overview of several studies on the clinical performance of all-ceramic fixed partial dentures. 'In-Ceram Fixed Partial Dentures: Three-Year Clinical Trial Results,' by J.A. Sorensen, et al, which appeared in the 1998 issue of the 'California Dental Association Journal; 'A Clinical Investigations on Three-Unit Fixed Partial Dentures Fabricated With A Lithium Disilicate Glass-Ceramic,' by J.A. Sorensen, et al.

Presents a study that measured the fracture resistance of three-unit fixed partial dentures made of ceramic core materials. Advice on selecting ceramic materials and techniques; Differences among mean failure loads of fixed partial dentures; Information on the law of beams in dentistry.

Part I. Analyzes the use of all-ceramic fixed partial dentures. Factor that plays a role in the strengthening mechanism of ceramic materials; Characteristic of a ceramic material that controls its mechanical failure; Evaluation of the flexural strength of CEREC 2 machined and jointed In-Ceram Alumina and In-Ceram Zirconia bars using a bending test.

An obituary for doctor John W. McLean is presented.

Objective: This in vitro study evaluated the long-term bond strength of adhesive bonding systems to yttrium-oxide partially stabilized zirconia ceramic (YPSZ). Materials and Methods: Industrially manufactured YPSZ disks were air abraded with 110 μ aluminum-oxide particles. Composite resin specimens were bonded to the pretreated ceramic surfaces with an alignment apparatus. Seven different surface treatment methods and bonding systems were included in this study (n = 16): Clearfil F2® (Kuraray Dental, Tokyo, Japan), Dyract Cem® (DeTrey/Dentsply, Konstanz, Germany), Kevloc® (Heraeus Kulzer, Wehrheim, Germany), Panavia® (Kuraray), Panavia 21® (Kuraray), Rocatec™ (3M ESPE, St. Paul, MN, USA), and Twinlook® (Heraeus Kulzer). Eight specimens per group were stored in distilled water at 37°C for either 3 days or 2 years and thermal cycled for 37,500 cycles between 5° and 55°C. Tensile bond strength was tested at a crosshead speed of 2 mm/min. The fractured interfaces were examined under a light microscope at x30 magnification to determine failure modes. Results: Conventional dimethacrylate composite resin had bond strengths that were initially low and, after the 2-year storage period, nonexistent. Specimens treated with Rocatec tribochemical coating had higher bond strengths after 3 days, which decreased by almost 50% during the storage period. Treatment with Kevloc resulted in bond strengths that were initially higher than with Rocatec. However, all specimens in this group spontaneously debonded during long-term storage. Bond strengths with Dyract Cem were relatively high initially with a dramatic decline after long-term water storage. Panavia and Panavia 21 had the significantly highest bond-strength values after 3 days and after 2 years of storage/thermal cycling. Bond strengths decreased slightly over the 2-year period, but the decreases were not statistically significant. The differences between these two groups also were not statistically significant. After 2 years of storage and thermal cycling, all specimens bonded with Twinlook, Clearfil F2, Kevloc, and Dyract Cem showed adhesive failure. The failures in the Panavia and Panavia 21 groups were exclusively cohesive. Mixed failure was seen in the Rocatec group (80% adhesive). Conclusions: Only the bonding systems containing an adhesive phosphate monomer (MDP) revealed strong and durable long-term resinbond strengths to YPSZ ceramic. All other materials in this study failed to achieve acceptable bond strengths after long-term storage and thermocycling. INSET: THE BOTTOM LINE: RESIN BOND TO DENTAL CERAMICS. [ABSTRACT FROM AUTHOR]

Objective: This in vitro study investigated the resin bond to glass-infiltrated aluminum oxide ceramic and the effects of various bonding methods and simulated aging. Materials and Methods: A total of 144 samples were fabricated from InCeram® (Vita Zahnfabrik, Bad Sackingen, Germany) glass-infiltrated alumina ceramic, sandblasted with 110 µm alumina (Al[sub2]O[sub3]) at 2.5 bars, and divided into six adhesive groups: (1) SAND--bonding agent and dimethacrylate composite resin cement (Adhesive Bond/Twinlook®, Heraeus Kulzer, Wehrheim, Germany); (2) SIL--silane coupling agent (ESPE-Sil™, 3M ESPE, St. Paul, MN, USA) and dimethacrylate composite resin cement; (3) ROC--tribochemical silica coating (Rocatec™, 3M ESPE), ESPE-Sil, and dimethacrylate composite resin cement; (4) SMD--thermal silica coating (Silicoater® MD, Heraeus Kulzer), ESPE-Sil and dimethacrylate composite resin cement; (5) PEX--phosphate-monomer-modified composite resin cement (Panavia EX®, Kuraray Dental, Tokyo, Japan); (6) PNS--experimental phosphate-monomer-modified composite resin cement (Panavia TPN-S®, Kuraray). Samples of Clearfil FII® (Kuraray) autocuring composite resin were bonded to the ceramic disks with an alignment apparatus, and a weight of 750 g was added. Excess resin was removed with pellets, and an oxygen-blocking gel was applied. Dual-curing dimethacrylate resin (groups SIL, ROC, and SMD) was light cured for 30 seconds from both sides and then placed in a light-curing unit for an additional 90 seconds. These groups were each divided into three subgroups to evaluate the effects of storage time and thermocycling: (1) storage for 24 hours without thermocycling, (2) storage for 30 days and thermocycling for 7,500 cycles between 5° and 55°C, (3) storage for 150 days and thermocycling for 37,500 cycles between 5° and 55°C. The storage medium was an isotonic artificial saliva solution at 37°C. Tensile bond strength was tested at a crosshead speed of 2 mm/min. A light microscope (x30 magnification) was used to determine the mode of fracture. Two specimens of each subgroup were randomly selected and examined with a scanning electron microscope (SEM). Results: Specimens in group SAND had the weakest bond strength of all groups after 1 day, and bond strength significantly decreased after 30 days; spontaneous debonding occurred after 150 days of storage and thermal cycling. Bond strength of group SIL was greater than that of group SAND after 1 day, decreased by > 50% after 30 days, and was very low after simulated aging. Resin bonds achieved in the ROC group were significantly higher than in groups SAND and SIL and remained stable after simulated aging. Bond strength for group SMD was about the same as for the ROC group after 1 day, did not change significantly after 30 days, and then dropped dramatically after 150 days of storage and thermal cycling. Results in the PEX group were similar to those in groups ROC and SMD after 1 and 30 days, with only a slight decrease after 150 days. The PNS group had the highest bond strength after 1 day, but it decreased substantially after 150 days. There was no statistically significant difference between the two phosphate monomer-modified composite resins (groups PEX and PNS). Failure modes for all samples in the SAND and SIL groups were adhesive, and they were cohesive for the ROC, PEX, and PNS groups. The failure mode was mixed for group SMD after 150 days. [ABSTRACT FROM AUTHOR]

Presents a study on the effects of treatment and storage conditions on ceramic bond strength. Materials and methods used in the study; Evidence for the need of adhesive technologies to support ceramics; Importance of acid-etching and silane application to achieve strong and durable resin bonds to silica-based ceramics.

Objective: This study evaluated the effect of different surface treatments on the surface morphology of densely sintered high-purity alumina and the influence of these treatments on the shear bond strength of a resin cement to this core material. Materials and Methods: Forty cylindric samples were fabricated from densely sintered high-purity aluminum-oxide ceramic (Procera®, Nobel Biocare AB, Gothenburg, Sweden) and divided into four groups of different surface treatments: (1) etching with hydrofluoric acid (9.6%) for 2 minutes followed by rinsing with air/water spray for 30 seconds; (2) sandblasting with a microetcher for 15 seconds using 50 µm alumina particles; (3) roughening with a diamond bur and etching with 37% phosphoric acid for 2 minutes followed by rinsing for 30 seconds with an air/water spray; (4) no treatment (control). The surfaces of all specimens were examined with an SEM to determine surface morphology. Four additional groups of specimens (n = 10) were prepared as described above and bonded with a dual-cure resin cement (EnForce®, Dentsply Caulk, Milford, DE, USA). The bonding areas were isolated and coated with EnForce silane coupling agent and EnForce bonding agent. After bonding, all specimens were stored at 100% humidity at room temperature for 1 week before shear bond strength was tested in an Instron® (Instron Corp, Canton, MA, USA) testing machine. Results: The SEM micrographs of the densely sintered high-purity alumina surfaces revealed a relatively rough and distinct microstructure in the control group. Surfaces after etching with hydrofluoric acid or diamond abrasion showed similar distinct boundaries. The sharp edges, however, appeared to be blunted in the specimens that were sandblasted. Bond strength tests identified sandblasting with alumina particles as the most effective surface treatment. Diamond-abraded specimens had higher bond strengths than those for the control group, but they were not significantly stronger than those for the hydrofluoric acid-etched group. Acid-etched samples had the weakest resin bond. Conclusions: SEM examination of densely sintered aluminum oxide ceramic illustrated its inherent surface morphology and the influence of different surface treatment methods. Sandblasting revealed the most pronounced alterations, that is, blunting of the sharp edges typically appearing with the other surface treatment methods and the control group. Sandblasting produced the significantly highest resin bond strengths. [ABSTRACT FROM AUTHOR]

Focuses on a study about the effects of adhesive technology on the success of all dental ceramic restorations. Review of laboratory and clinical studies of the influence of cementation media selection on the performance of all ceramic restorations; Variations in the fracture strengths of materials used for all ceramic restorations; Conclusion of the study.

Focuses on a study that evaluated methods to improve the bond strength of silanes to silica-based dental ceramics. Materials and methods used in the study; Comparisons of silane application procedures; Capability of the silane application method to eliminate the need for hydrofluoric acid etching.

Focuses on a study about dental bond strength and durability of various ceramic bonding systems bonded to feldspathic porcelain. Materials and methods used in the study; Effect of the absence of a priming agent on bond strength of ceramic bonding systems; Importance of silane coupling and bonding agents.

Purpose: Procera Alumina crowns are widely used; however, the effect of crown margin design on marginal fit is unknown. This study measured and compared the precision of fit of Procera Alumina crowns with two crown margin designs: all-porcelain versus alumina-supported margins., Materials and Methods: Sixteen noncarious extracted human premolars were prepared for Procera((R)) Alumina crowns with an internally rounded shoulder preparation. Impressions were made from all teeth, and master dies were poured with type IV dental stone. The specimens were randomly divided into two groups. Procera Alumina crowns were fabricated: eight crowns with circumferential porcelain-butt (all-porcelain) margins and eight crowns with coping (alumina-supported) margins (control). Precision of fit was measured at six points on each crown with a profilometer (profile projector). The data were statistically analyzed with an independent-samples t-test (alpha < 0.05)., Results: The mean marginal gap size (microm) of coping margins was 68.07 +/- 16.08 and of porcelain-butt margins was 101.29 +/- 43.71. There was no statistically significant difference (p= 0.065) of the marginal gap size between coping margins and porcelain-butt margins., Conclusion: The results of this study demonstrate that there was no statistically significant difference in the marginal fit of coping and porcelain-butt margins. Both margin designs are within clinically acceptable ranges. Therefore, clinicians may choose to use a coping margin, as it is less labor intensive and requires less time for fabrication, unless there is a specific high esthetic need for a porcelain-butt margin.