40 Questions
What is the estimated daily release of lithium from dental ceramics?
30 μg
What is the recommended daily intake of lithium for manic-depressive patients?
600–2,100 μg/day
What is the name of the lung disease caused by inhalation of ceramic dust?
Silicosis
Why is the risk of silicosis considered 'very minimal' for patients?
Because patients follow safety measures
What is the acceptable daily intake of lithium?
2,000 μg/day
What is the surface area of the crowns in the worst-case calculation?
74 cm2
What is the temperature used in the worst-case calculation?
80°C
What is the pH used in the worst-case calculation?
pH 11
What are dental ceramics primarily used for?
All of the above
What is a unique property of certain ceramic materials?
They can accelerate biological processes
What is a common use of aluminum oxide and zirconium oxide ceramics?
Orthopedic implants and joint replacements
How are ceramic materials shaped?
Through sintering, casting, pressing, milling, and sonoerosion
What is a common combination used in dental restorations?
Metal and ceramic
What is a characteristic of high-performance ceramics?
They have excellent technical properties
Why are silicon oxide ceramics used in dental restorations?
To improve the aesthetics of the restoration
What is a potential benefit of using bioactive ceramic materials?
They can accelerate biological processes
What is the primary basis for the classification of dental ceramics?
Chemical composition
Which type of ceramic material is commonly used in dentistry due to its white color?
Silicon oxide
What is the primary purpose of coating metal implants with calcium phosphate ceramics?
To transform the metallic surface into a more bioactive state
What is the main characteristic of bioglasses, a type of silicon oxide ceramic?
Bioactive properties
What is the reason for the initial strength decrease in dental ceramics over time?
Permanent load and aqueous media
What is the term used to describe a feldspathic ceramic used for the veneering of titanium?
Titanium ceramic
What is the nature of degradation in dental ceramics?
Both chemical and mechanical
What is the purpose of engineering certain calcium phosphate ceramics for gradual resorption?
To facilitate their integration with bone tissue
What is the effect of increasing the concentration of titanium and zirconia microparticles on macrophage cytotoxicity?
It increases macrophage cytotoxicity
What is the effect of LPS on the proinflammatory effect of titanium and zirconia microparticles?
It exacerbates the proinflammatory effect
How do titanium particles induce a foreign body reaction?
By inducing macrophages to phagocytize and polarize to M1 type
How do titanium and titanium oxides affect the methylation level of cellular DNA?
By regulating the expression of DNA Class A transferase (DNMT)
What is the effect of Wnt/β-catenin signaling pathway on titanium-induced inflammation?
It inhibits inflammation
How do bacterial corrosion and titanium particles interact to affect inflammation?
Bacterial corrosion promotes the release of titanium particles, which can promote inflammation
What is the effect of ZrO2 particles compared to TiO2 particles on toxicity and inflammatory cytokine production?
ZrO2 particles cause reduced toxicity and inflammatory cytokine production
What is the effect of titanium particles on the NLRP3 inflammasome?
It inhibits the NLRP3 inflammasome
What is the primary reason for the high radioactivity of zirconium oxide ceramic?
Impurities in the raw materials
What is the approximate activity concentration of zircon powder?
11,500 Bq/kg
What is the effective activity of zirconium oxide ceramic compared to the administrative threshold?
Below the threshold of 1 mSv/year
What is the activity concentration of feldspathic ceramic specimens?
0.015 Bq/g
What is the source of higher levels of γ radiation in feldspathic ceramic?
Naturally occurring potassium 40
What is the calculated activity concentration of potassium 40 in feldspathic ceramic?
Below 10 Bq/g
Have radiation-related health problems been reported in patients using ceramic prostheses?
No, in any case
Are all activity measurements of dental ceramics within the limits of ISO and EC?
Yes, they are
Study Notes
Systemic Toxicity and Allergies
- Worst-case calculations indicate a daily release of 30 μg of lithium from dental ceramics, which is well below the acceptable daily intake of 2,000 μg/day.
- Lithium released from dental ceramics is unlikely to cause unwanted side effects in patients.
Systemic Toxicity
- Ceramics are generally considered to have extremely low systemic toxicity and allergenic potency.
- Dental laboratory technicians may be exposed to ceramic dust, which can cause silicosis (fibrotic pneumoconiosis) if proper safety measures are not followed.
Local Toxicity and Tissue Compatibility
- Certain ceramics, such as those used for implants, are inert or tolerated by tissue and can even accelerate biological processes by releasing ions that promote new bone growth.
- Some ceramics, including aluminum oxide and zirconium oxide ceramics, are used in orthopedics and may be suitable for dental applications.
Composition
- Dental ceramics can be classified based on their chemical composition, with oxides (e.g., silicon oxide, aluminum oxide, zirconium oxide) being the most important in dentistry.
- Non-oxides, such as silicon carbide and silicon nitrite, are less important in dentistry due to their black color.
Release and Degradation
- Dental ceramics are commonly regarded as insoluble or only very slightly soluble, but their initial strength decreases significantly over time due to chemical and mechanical degradation.
Radioactivity of Zirconium Oxide Ceramic
- Zirconium oxide ceramic has a higher level of radioactivity compared to aluminum oxide and silicon oxide ceramic due to contaminants in the raw materials.
- The radioactivity of zirconium oxide ceramic depends on the purity of the raw materials and has been significantly reduced through purification procedures.
Radioactivity of Feldspathic Ceramic
- Feldspathic ceramic specimens showed a low activity concentration of 0.015 Bq/g, which is similar to the activity of the human body.
- The calculated activity concentration is below the threshold limit, and no radiation-related adverse effects of dental ceramics have been documented in the literature.
This quiz covers the toxicological effects of lithium, its release, and acceptable daily intake, particularly in the context of treating manic-depressive patients. It also touches on the daily alimentary intake of lithium.
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