• Journal of the Korean Academy of Esthetic Dentistry
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• v.22 no.1
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• pp.30-46
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• 2013

Porcelain fused to metal crown has been used mostly over the last 50 years for restorations in dentistry. However, the patients' awareness of aesthetic aspect, biocompatibility and the problems such as an allergy to metals led to the growing interest in the 'metal free restoration'. In particular, the price of the precious metals that have been mainly used to date has risen drastically, which made them impossible to play their role as oral restorative materials anymore, and in addition, the PFM restoration has intrinsic problems of chipping and fracture. Therefore, the CAD/CAM has been drawing more attention than ever due to the popular needs for the material that is more aesthetic and stronger for restoration of the molar implant. Considerations in carrying out the full zirconia restoration are as follows: 1) strength, 2) combination work, 3) light penetrability, 4) treatment of cracks, 5) the color reproducibility of the block, 6) the abrasivity of antagonistic tooth, 7) low temperature degradation. In this presentation, the color reproducibility of the block will be discussed. One of the biggest reasons for avoiding the full zirconia restoration is that it is difficult to reproduce the natural color compared to the conventional PFM restoration. Thus, many clinicians show reluctance due to the exposure of the ugly block when the coloring on the surface is removed after occlusal adjustment. From the experience of using blocks by Zirkonzahn for more than 4 years, it is considered that these problems can be addressed to some degrees. Accordingly, how to make restorations that are well in harmony with surrounding prosthesis or natural teeth will be discussed.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.3
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• pp.253-268
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• 2012

Full-mouth reconstruction of a patient using dental implants is a challenge if there is vertical and horizontal bone resorption, since this includes the gingival area and restricts the position of the implants. however, hard- and soft-tissue grafting may allow the implants to be placed into the desired position. Although it is possible to regenerate lost tissues, an alternative is to use fixed detachable prostheses that restore the function and the esthetics of the gingiva and teeth. Various material combinations including metal/acrylic, metal/ceramic, and zirconia/ceramic have been used for constructing this type of restoration. Other problems include wear, separation or fracture of the resin teeth from the metal/acrylic prosthesis, chipping or fracture of porcelain from the metal/ceramic or zirconia/ceramic prosthesis, and fracture of the framework in some free-end prostheses. With virtually unbreakable, chip-proof, life-like nature, monolithic zirconia frameworks can prospectively replace other framework materials. This clinical report describes the restoration of a patient with complete fixed detachable maxillary and mandibular prostheses made of monolithic zirconia with dental implants. The occluding surfaces were made of monolithic zirconia, to decrease the risk of chipping or fracture. The prostheses were esthetically pleasing, and no clinical complications have been reported after two years.

• The korean journal of orthodontics
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• v.45 no.6
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• pp.299-307
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• 2015

Objective: The aims of this study were to compare the shear bond strength between orthodontic metal brackets and glazed zirconia using different types of primer before applying resin cement and to determine which primer was more effective. Methods: Zirconia blocks were milled and embedded in acrylic resin and randomly assigned to one of four groups: nonglazed zirconia with sandblasting and zirconia primer (NZ); glazed zirconia with sandblasting, etching, and zirconia primer (GZ); glazed zirconia with sandblasting, etching, and porcelain primer (GP); and glazed zirconia with sandblasting, etching, zirconia primer, and porcelain primer (GZP). A stainless steel metal bracket was bonded to each target surface with resin cement, and all specimens underwent thermal cycling. The shear bond strength of the specimens was measured by a universal testing machine. A scanning electron microscope, three-dimensional optical surface-profiler, and stereoscopic microscope were used to image the zirconia surfaces. The data were analyzed with one-way analyses of variance and the Fisher exact test. Results: Group GZ showed significantly lower shear bond strength than did the other groups. No statistically significant differences were found among groups NZ, GP, and GZP. All specimens in group GZ showed adhesive failure between the zirconia and resin cement. In groups NZ and GP, bonding failed at the interface between the resin cement and bracket base or showed complex adhesive and cohesive failure. Conclusions: Porcelain primer is the more appropriate choice for bonding a metal bracket to the surface of a full-contour glazed zirconia crown with resin cement.

• The Journal of Advanced Prosthodontics
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• v.5 no.2
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• pp.209-217
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• 2013

This clinical report presents the reconstruction of a maxillary arch with a cement retained implant supported fixed prosthesis using a monolithic zirconia generated by CAD/CAM system on eight osseointegrated implants. The prosthesis was copy milled from an interim prosthesis minimizing occlusal adjustments on the definitive prosthesis at the time of delivery. Monolithic zirconia provides high esthetics and reduces the number of metal alloys used in the oral cavity.

• The Journal of Advanced Prosthodontics
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• v.7 no.2
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• pp.146-150
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• 2015

PURPOSE. This in vitro study aimed to compare the failure load and failure characteristics of two different zirconia framework designs of premolar crowns when subjected to static loading. MATERIALS AND METHODS. Two types of zirconia frameworks, conventional 0.5 mm even thickness framework design (EV) and 0.8 mm cutback of full contour crown anatomy design (CB), were made for 10 samples each. The veneer porcelain was added on under polycarbonate shell crown made by vacuum of full contour crown to obtain the same total thickness of the experiment crowns. The crowns were cemented onto the Cobalt-Chromium die. The dies were tilted 45 degrees from the vertical plane to obtain the shear force to the cusp when loading. All crowns were loaded at the lingual incline of the buccal cusp until fracture using a universal testing machine with cross-head speed 0.5 mm/min. The load to fracture values (N) was recorded and statistically analyzed by independent sample t-test. RESULTS. The mean and standard deviations of the failure load were $1,170.1{\pm}90.9$ N for EV design and $1,450.4{\pm}175.7$ N for CB design. A significant difference in the compressive failure load was found (P<.05). For the failure characteristic, the EV design was found only cohesive failures within veneering porcelain, while the CB design found more failures through the zirconia framework (8 from 10 samples). CONCLUSION. There was a significant difference in the failure load between two designs, and the design of the framework influences failure characteristic of zirconia crown.

• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.3
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• pp.224-231
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• 2016

Severe dental attrition causes pathological changes of the tooth, imbalanced occlusion, and functional and aesthetic complications and can also result in a decrease in occlusal vertical dimension that can incur temporomandibular joint and muscular complications. Before restoring the vertical dimension with full-mouth prosthetic restorations, it is important to determine the amount of vertical lifting through complete diagnosis. In this study, a 59 year-old male patient with generalized attrition and fracture of teeth was treated with full-mouth zirconia prosthetic restoration in order to recover vertical dimension and aesthetics. Through the analysis of physiologic rest position and inter-canine distance, the treatment was planned for lifting 3 mm in vertical dimension. Interim crown were fabricated after full-mouth wax up, having the patient use for 6 months. The final monolithic and bilayered zirconia restorations were completed. The patient showed satisfaction in function and aesthetics for 18 months of follow-up since delivering the final restorations.

• Journal of Dental Rehabilitation and Applied Science
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• v.31 no.3
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• pp.231-241
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• 2015

As patients' esthetic expectations increase, there is an increase in demand for cosmetic restorations of anterior and posterior teeth that resemble the natural tooth morphology and color. An example of high-strength all-ceramic systems is zirconia with CAD/CAM application. This case report describes a full-mouth rehabilitation using zirconia all-ceramic crowns supported by upper and lower implants and by a minimal increase in the occlusal vertical dimension in a patient with severe abrasion due to loss of posterior teeth.

• Journal of Dental Rehabilitation and Applied Science
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• v.34 no.3
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• pp.196-207
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• 2018

An accurate implant placement with ideal location is significant for long-term success of the implant. An exact evaluation of nearby anatomic structures such as quality of residual bone, an inferior alveolar bone and a maxillary sinus is required. For a prosthetic-driven treatment, planned surgery, precise prosthesis and communication with the patient are significant requisites especially for full-mouth rehabilitation. In this case, the patient with severe alveolar bone resorption had a CT guided surgery supported by CT data and the data from scanning diagnostic wax-up. Afterward, edentulous area was restored by full mouth implant-supported prosthesis by using monolithic zirconia and CAD/CAM technique. This paper reports the outcome of the procedure which was remarkable both esthetically and functionally.

• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.3
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• pp.202-208
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• 2016

The progressive attrition of teeth is a normal process by aging. However, excessive tooth wear with decreased vertical dimension of occlusion and collapse of occlusal plane may cause pathologic pulpal condition, occlusal disharmony and functional disorders. In this case, a patient with severely worn dentition was treated. Diagnostic wax-up was performed at the increased vertical dimension. After evaluation of provisional restorations for 12 weeks, final restorations were fabricated with zirconia crown and routine clinical assessments were made. Esthetically and functionally satisfactory results were obtained.

• The Journal of Advanced Prosthodontics
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• v.2 no.3
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• pp.111-115
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• 2010

PURPOSE. This study was conducted to evaluate clinical validity of a zirconia full-coverage crown by comparing zirconia's wear capacity over antagonistic teeth with that of feldspathic dental porcelain. MATERIALS AND METHODS. The subject groups were divided into three groups: the polished feldspathic dental porcelain group (Group 1), the polished zirconia group (Group 2), and the polished zirconia with glazing group (Group 3). Twenty specimens were prepared from each group. Each procedure such as plasticity, condensation, and glazing was conducted according to the manufacturer's manual. A wear test was conducted with 240,000 chewing cycles using a dual-axis chewing simulator. The degree of wear of the antagonistic teeth was calculated by measuring the volume loss using a three-dimensional profiling system and ANSUR 3D software. The statistical significance of the measured degree of wear was tested with a significant level of 5% using one-way ANOVA and the Tukey test. RESULTS. The degrees of wear of the antagonistic teeth were $0.119{\pm}0.059\;mm^3$ in Group 1, $0.078{\pm}0.063\;mm^3$ in Group 3, and $0.031{\pm}0.033\;mm^3$ in Group 2. Statistical significance was found between Group 1 and Groups 2 and between Group 2 and 3, whereas no statistical significance was found between Group 1 and Group 3. CONCLUSION. Despite the limitations of this study on the evaluation of antagonistic teeth wear, the degree of antagonistic tooth wear was less in zirconia than feldspathic dental porcelain, representing that the zirconia may be more beneficial in terms of antagonistic tooth wear.