This study aimed to compare the vertical marginal gap of teeth restored with lithium disilicate crowns fabricated using CAD/CAM or by pressed ceramic approach. Twenty mandibular third molar teeth were collected after surgical extractions and prepared to receive full veneer crowns. Teeth were optically scanned and lithium disilicate blocks were used to fabricate crowns using CAD/CAM technique. Polyvinyl siloxane impressions of the prepared teeth were made and monolithic pressed lithium disilicate crowns were fabricated. The marginal gap was measured using optical microscope at 200× magnification (Keyence VHX-5000, Japan). Statistical analysis was performed using Wilcoxon test. The lithium disilicate pressed crowns had significantly smaller (p = 0.006) marginal gaps (38 ± 12 μm) than the lithium disilicate CAD/CAM crowns (45 ± 12 μm). This research indicates that lithium disilicate crowns fabricated with the press technique have measurably smaller marginal gaps compared with those fabricated with CAD/CAM technique within in vitro environments. The marginal gaps achieved by the crowns across all groups were within a clinically acceptable range.

• MeSH
• design s pomocí počítače * MeSH
• lidé MeSH
• materiály pro zubní otisky MeSH
• neparametrická statistika MeSH
• referenční hodnoty MeSH
• referenční standardy MeSH
• reprodukovatelnost výsledků MeSH
• testování materiálů MeSH
• zubní korunky normy   MeSH
• zubní marginální adaptace normy   MeSH
• zubní porcelán chemie   MeSH
• zubní protéza - design MeSH
• zubní technika otisková * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH

x

Crowns and Fixedpartials dentures experience a rapid shift toward ceramic materials, partially for their aesthetics. However, ceramics are susceptible to fracture, comparable to metal frameworks. Porcelains with the most desirable aesthetics tend also to have the lowest toughness. Conversely, tougher ceramics such as zirkonias are not generally aesthetic. Glass-ceramics are in the middle of the scale. Failures in dental ceramics may arise during fabrication in a laboratory. They can take the form of microstructural defects, often below visual contact. In the presented study there was a need to unglue abutment crown to correct colour. Coefficient of thermal expansion between glass-ceramic core and titanium base led to tensile stress and subsequent fracture of the crown. The new zirkonia-based ceramic crown was a material of choice, especially for its high flexural strength.

• MeSH
• implantace zubů MeSH
• lidé MeSH
• mechanický stres MeSH
• premolár MeSH
• titan MeSH
• zirkonium MeSH
• zubní fazety MeSH
• zubní implantáty MeSH
• zubní korunky MeSH
• zubní materiály MeSH
• zubní náhrada ve spojení s implantáty * MeSH
• zubní náhrady - opravy * MeSH
• zubní porcelán MeSH
• zuby-sanace - selhání * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• kazuistiky MeSH

STATEMENT OF PROBLEM: The vertical marginal discrepancy of restorations can increase upon cementation, and poor marginal fit can lead to cement dissolution, marginal discoloration, microleakage, and secondary caries. The amount of increase is related to the type of luting cement used, but how lithium disilicate pressed crowns are affected by different resin cements is unclear. PURPOSE: The purpose of this in vitro study was to compare the effect of using different resin luting cements on the vertical marginal discrepancy of lithium disilicate pressed crowns. MATERIAL AND METHODS: A total of 18 intact extracted mandibular third molars were disinfected in a solution of 10% formalin for 7 days and were then prepared to receive a ceramic crown. Impressions were made with polyvinyl siloxane and lithium disilicate pressed crowns made and cemented with 1 of 3 resin luting cements. The marginal discrepancy was measured at 4 points on the finishing line of each tooth, with optical microscopy at ×200 magnification before and after cementation. Statistical analysis was done with the Kruskal-Wallis test to compare the median marginal increase among the 3 groups (a=.05). RESULTS: The least amount of marginal increase after cementation was with Harvard PremiumFlow cement, with an average marginal increase of 42 ±11 μm. RelyX Ultimate cement increased the margins by an average 45 ±29 μm. The highest marginal increase was found in the Enamel Plus HRi preheated composite resin group (116 ±47 μm). CONCLUSIONS: The marginal increase of pressed crowns cemented with preheated composite resin (Enamel Plus HRi) exceeded the clinically acceptable range of marginal discrepancy.

• MeSH
• lidé MeSH
• moláry MeSH
• pryskyřičné cementy * MeSH
• techniky in vitro MeSH
• zubní cementy * MeSH
• zubní korunky * MeSH
• zubní porcelán * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

The effect of warm air-blowing on the sealing ability of two one-bottle and one two-bottle silane-containing universal adhesives (UAs) applied to lithium disilicate ceramics (LDS) was evaluated. Tapered cavities prefabricated in LDS blocks (IPS e.max CAD) were treated by the adhesives, air-blown either with normal air (23±1°C) or warm air (60±5°C), and filled with a flowable resin composite. Interfacial gap formation was observed using swept-source optical coherence tomography immediately after filling, after 24 h, 5,000 and 10,000 thermal cycles, and an additional 1-year water storage. Specimens bonded using normal air-blown one-bottle UAs exhibited a significantly higher gap formation than the two-bottle UA (p<0.001), and detached within 24 h. Warm air-blowing significantly decreased the gap formation of one-bottle UAs (p<0.001), but the specimens dislocated within 24 h or during thermocycling. The two-bottle UA withstood all aging procedures and warm air-blowing significantly decreased its 1-year gap formation compared to normal air-blowing (p=0.002).

• MeSH
• keramika MeSH
• povrchové vlastnosti MeSH
• pryskyřičné cementy MeSH
• silany * MeSH
• testování materiálů MeSH
• vazba zubní * MeSH
• zubní cementy MeSH
• zubní porcelán MeSH
• Publikační typ
• časopisecké články MeSH

OBJECTIVES: To explore fatigue limits of ceramic endocrowns for premolars. METHODS: Forty-eight devitalized premolars were cut at the CEJ. They were restored with standardized CAD-CAM lithium disilicate reinforced ceramic restorations (IPS e.max CAD, Ivoclar-Vivadent) and divided into four Groups (n=12): overlays (Group A, no endo-core, negative control), endocrowns with an endo-core of 2mm (Group B), 4mm (GroupC) and crowns with post and core (Group D, positive control). All specimens were first submitted to thermo-mechanical cyclic loading (TCML)(1.7Hz, 49N, 600000 cycles, 1500 thermo-cycles). Margins were analysed before and after the loading. Survived specimens were then submitted to cyclic isometric stepwise loading (5Hz, 200N to 1200N) until completion of 105000 cycles or failure. In case of fracture, fragments were analysed using SEM and failure mode was determined. Results of stepwise loading were statistically analysed by Kaplan-Meier life survival analysis and log rank test (p=0.05). RESULTS: All the specimens survived the TCML test except four specimens of Group A (early restorations' debonding). No difference in percentages of closed margins was found between endocrowns (Groups B, C) and crowns (Group D). After the stepwise test, differences in survival within the groups were not statistically significant. Most of restorations experienced non-reparable fracture. CONCLUSIONS: Endocrowns with both 2-mm and 4-mm long endo-cores displayed outcomes after fatigue equivalent to classical crowns. Results of this study discourage the use of flat overlays with only adhesive retention. CLINICAL SIGNIFICANCE: When restoring extremely destroyed devitalized premolars, adhesive strategies should be coupled to a macro-mechanical retention in the root.

• MeSH
• analýza přežití MeSH
• analýza zatížení zubů MeSH
• cementování MeSH
• design s pomocí počítače * MeSH
• keramika MeSH
• lidé MeSH
• mechanický stres MeSH
• pevnost v tlaku MeSH
• premolár * MeSH
• testování materiálů MeSH
• trvalá zubní náhrada MeSH
• výsledek terapie MeSH
• zubní korunky * MeSH
• zubní krček MeSH
• zubní marginální adaptace MeSH
• zubní materiály * MeSH
• zubní porcelán chemie   MeSH
• zubní protéza - design * MeSH
• zuby neživé * MeSH
• zuby-sanace - selhání MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Práce se zabývá testováním cytototoxicity in vitro vybraných vzorků dentálních celokeramických materiálů. Materiály byly podrobeny testu přímého kontaktu a testu extraktu. Testy byly prováděny na populaci buněčné linie myších fibroblastů NIH 3T3 v buněčné kultuře. Z výsledků je patrné, že všechny materiály mohou být považovány za netoxické kromě lithium disilikátové keramiky.

Paper presents cytotoxicity testing procedure in vitro of preselected dental ceramics. Direct contact test and extract test were monitored. A population of mouse fibroblasts NIH 3T3 was used for both tests. Results show all tested dental ceramics can be considered non-cytotoxic, except the lithium disilicate material.

• Klíčová slova
• keramické dentální materiály,
• MeSH
• buňky 3T3 MeSH
• financování organizované MeSH
• keramika chemie   škodlivé účinky   MeSH
• myši MeSH
• sloučeniny lithia škodlivé účinky   MeSH
• techniky in vitro MeSH
• zubní materiály MeSH
• Check Tag
• myši MeSH

OBJECTIVES: This study aimed to investigate the impact of bleaching agents based on carbamide or hydrogen peroxide on dental ceramics in vitro, utilizing scanning electron microscopy (SEM) and elemental analysis via inductively coupled plasma optical emission spectroscopy (ICP-OES). METHODS: CAD/CAM ceramics (IPS e.max®CAD, IPS Empress®CAD, Vitablocs® Mark II, Celtra Duo, and inCoris TZI) were treated with bleaching agents using either 10%, 20%, 30% carbamide peroxide or with 35%, and 40% hydrogen peroxide. RESULTS: Surface elemental release was not significantly affected by the type or concentration of bleaching agent (p>0.05). Ion release in feldspathic ceramics was significantly higher than in other ceramic materials (p⟨0.0001). Microstructural surface changes were observed in all materials except for lithium disilicate and zirconia-reinforced lithium silicate ceramics. CONCLUSIONS: All bleaching agents tested in this study showed a similar impact within each material type tested regarding total mass loss, elemental composition, or surface structure. CLINICAL RELEVANCE: Lithium disilicate and zirconia-reinforced lithium silicate ceramics were the most resistant to bleaching agents. In contrast, feldspathic ceramic showed the highest ion release and surface deterioration when exposed to all bleaching agents tested.

• MeSH
• design s pomocí počítače * MeSH
• karbamidperoxid * chemie   MeSH
• keramika * chemie   MeSH
• látky na bělení zubů * chemie   MeSH
• mikroskopie elektronová rastrovací MeSH
• peroxid vodíku * chemie   MeSH
• povrchové vlastnosti MeSH
• testování materiálů MeSH
• zirkonium chemie   MeSH
• zubní porcelán * chemie   MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• estetika stomatologická MeSH
• Publikační typ
• sborníky MeSH

• Konspekt
• Stomatologie
• NLK Obory
• zubní lékařství
• NLK Publikační typ
• brožury

• MeSH
• dentální technologie MeSH
• design s pomocí počítače MeSH
• zubní materiály MeSH
• Publikační typ
• přehledy MeSH

• Konspekt
• Stomatologie
• NLK Obory
• zubní lékařství
• technika lékařská, zdravotnický materiál a protetika
• NLK Publikační typ
• brožury

The effect of curing mode of dual-cure resin cements on the tensile bond strength (TBS) of universal adhesives to enamel, dentin, zirconia, lithium disilicate ceramics (LDS), feldspathic porcelain (FP), and a Pd-Au alloy was evaluated. The substrates were bonded using Tokuyama Universal Bond (TUB) or Scotchbond Universal Adhesive (SBU), followed by luting with Estecem II (ECII) or Rely-X Ultimate (RXU), respectively, which were used either in light-curing or self-curing mode. The TBS test was performed after 24 h or 5,000 thermal cycles. Light-curing significantly improved the 24-h TBS of TUB/ECII to enamel, dentin and FP, as well as the TBS of SBU/RXU to all substrates except LDS. After thermal cycling, light-curing significantly increased the TBS of both adhesives/cements to dentin, but significant differences between curing modes were seldom observed for other substrates. This suggested that light-curing is essential for the hydrophilic dentin, but self-curing might be sufficient for other substrates.

• MeSH
• dentin MeSH
• dentinová adheziva MeSH
• pevnost v tahu MeSH
• pryskyřičné cementy * MeSH
• testování materiálů MeSH
• vazba zubní * MeSH
• zubní cementy MeSH
• zubní sklovina MeSH
• Publikační typ
• časopisecké články MeSH