Analysis of Internal Defects in All-ceramic Crowns Using Micro-focus X-ray Computed Tomography

Nakamura, Takashi; Wakabayashi, Keiji; Kawamura, Yoshiko; Kinuta, Soichiro; Mutobe, Yoshihiko; Yatani, Hirofumi

doi:10.4012/dmj.26.598

Cited by 18 publications

(12 citation statements)

References 17 publications

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“…Quality of the porcelain layering or layering technique—Pores represent stress concentrations within the restoration. Micro‐CT analysis of ceramic crowns revealed numerous pores within the veneer porcelain for CAD/CAM frameworks as well as heat‐pressed veneers . In contrast, another study showed that pressed veneers performed better than hand‐layered veneers, with less surface degradation, fewer chipping fractures, and fewer bulk fractures …”

Section: Discussionmentioning

confidence: 99%

Randomized Clinical Trial of Implant‐Supported Ceramic–Ceramic and Metal–Ceramic Fixed Dental Prostheses: Preliminary Results

Esquivel‐Upshaw

Clark

Shuster

et al. 2013

Journal of Prosthodontics

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Purpose The aim of this study was to determine the survival rates over time of implant-supported ceramic-ceramic and metal-ceramic prostheses as a function of core-veneer thickness ratio, gingival connector embrasure design, and connector height. Materials and Methods An IRB-approved, randomized, controlled clinical trial was conducted as a single-blind pilot study involving 55 patients missing three teeth in either one or two posterior areas. These patients (34 women; 21 men; age range 52–75 years) were recruited for the study to receive a 3-unit implant-supported fixed dental prosthesis (FDP). Two implants were placed for each of the 72 FDPs in the study. The implants (Osseospeed, Astra Tech), which were made of titanium, were grit blasted. A gold-shaded, custom-milled titanium abutment (Atlantis, Astra Tech), was secured to each implant body. Each of the 72 FDPs in 55 patients were randomly assigned based on one of the following options: (1) A. Material: ceramic-ceramic (Yttria-stabilized zirconia core, pressable fluorapatite glass-ceramic, IPS e.max ZirCAD and ZirPress, Ivoclar Vivadent) B. metal-ceramic (palladium-based noble alloy, Capricorn, Ivoclar Vivadent, with press-on leucite-reinforced glass-ceramic veneer, IPS InLine POM, Ivoclar Vivadent); (2) occlusal veneer thickness (0.5, 1.0, and 1.5 mm); (3) curvature of gingival embrasure (0.25, 0.5, and 0.75 mm diameter); and (4) connector height (3, 4, and 5 mm). FDPs were fabricated and cemented with dual-cure resin cement (RelyX, Universal Cement, 3M ESPE). Patients were recalled at 6 months, 1 year, and 2 years. FDPs were examined for cracks, fracture, and general surface quality. Results Recall exams of 72 prostheses revealed 10 chipping fractures. No fractures occurred within the connector or embrasure areas. Two-sided Fisher’s exact tests showed no significant correlation between fractures and type of material system (p = 0.51), veneer thickness (p = 0.75), radius of curvature of gingival embrasure (p = 0.68), and connector height (p = 0.91). Conclusions Although there were no significant associations between connector height, curvature of gingival embrasure, core/veneer thickness ratio, and material system and the survival probability of implant-supported FDPs with zirconia as a core material, the small number of fractures precludes a definitive conclusion on the dominant controlling factor.

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Section: Discussionmentioning

confidence: 99%

Randomized Clinical Trial of Implant‐Supported Ceramic–Ceramic and Metal–Ceramic Fixed Dental Prostheses: Preliminary Results

Esquivel‐Upshaw

Clark

Shuster

et al. 2013

Journal of Prosthodontics

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“…Even more fractures occurred when they were stored in saline solution for 5 days before debonding. Since porcelain is known to take up water, as it does when in the mouth over time 22–24, it would be understandable that the in saline solution stored veneers fractured more frequently and rapidly. Indeed, some of the saline solution stored veneers fractured only 3 seconds after laser application.…”

Section: Discussionmentioning

confidence: 99%

Er:YAG laser debonding of porcelain veneers

et al. 2011

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“…Pigmented silicone prostheses exposed to daylight can exhibit less color change if the silicone is mechanically mixed under vacuum; however, pore‐free silicone prostheses are likely to be more color stable than porous prostheses. The Micro‐CT scanning in investigating porosity analysis preserved the specimens and provided adequate data from a single scan; 4,26 however, its cost, artifact generation decreasing image quality, and high skill required might preclude its use.…”

Section: Discussionmentioning

confidence: 99%

“…The presence of pores within mixtures has been investigated by conducting invasive protocols of sectioning specimens into slices of controlled thickness, then investigating the slices using scanning electron microscopy 2 light or stereo microscopy 8,25 . Other protocols were noninvasive, using X‐ray microfocus computerized tomography (Micro‐CT) 4,7,26 in analyzing pores (number, size, volume, and percentage) of different materials including all‐ceramic crowns 26 and encapsulated glass ionomer cements 4 . Although environmental and patient factors that affect silicone prostheses’ functionality have been investigated thoroughly in the literature, 27–30 material handling properties of air bubble formation during mixing have not been evaluated.…”

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confidence: 99%