What is zinc phosphate cement?
The resulting zinc phosphate cement in such formulations is an opaque solid that consists of excess zinc oxide coated and bonded by, possibly, aluminum phosphate and zinc phosphate gels. The cement is porous and permeable to dyes [22].
What is the initial setting time of zinc phosphate cement?
This setting reaction results in insoluble zinc phosphate, which is the set form of dental cement. The initial setting time of the zinc phosphate cement is around 5 minutes. The setting time depends upon numerous factors such as temperature, humidity, and particle size of the dental cement powder.
Why does zinc phosphate cement form a weak bond with tooth structure?
Zinc phosphate cement forms a weak bond with the tooth structure because it does not form a chemical bond with the tooth structure. The bonding of cement is by mechanical means similar to zinc oxide eugenol dental cement.
What is phosphate cement used for in dentistry?
Zinc phosphate is the most important phosphate cement and is widely used as “permanent” dental cement. It is also modified with silicones to produce dental filling materials. Compressive strengths up to 200 MPa are typical of these materials, which are formulated to have good resistance to water.
When was zinc phosphate cement introduced?
Zinc phosphate cement was introduced c. 1879, and although the formulation has been refined for more than a century, it is a luting agent that has consistently been successful in clinical practice and even today is still considered the 'gold' standard.
Who invented zinc polycarboxylate cement?
SmithZinc polycarboxylate cement was invented by Smith (1968) at the end of 1960s. When the powder and the liquid were mixed, the acid is neutralized by the basic ZnO, and Zn polyacrylate salt is formed. The salt has a structure in which deprotonated carboxyl groups are ionically cross-linked with Zn2+ ions.
What is zinc phosphate cement?
Zinc phosphate cement the one of the oldest and widely used cements, and is commonly used for luting permanent metal restorations and as a base. It is a high-strength cement base, mixed from zinc oxide powder and phosphoric acid liquid.
How do you make zinc phosphate cement?
1:019:42Preparation of Zinc Phosphate - YouTubeYouTubeStart of suggested clipEnd of suggested clipThe materials needed to prepare zinc phosphate are zinc phosphate liquid which is dispensed from aMoreThe materials needed to prepare zinc phosphate are zinc phosphate liquid which is dispensed from a dropper bottle.
Who invented glass ionomer cement?
Glass-ionomers were invented in 1969 and reported by Wilson and Kent in the early 1970s. Glass-ionomer cement components, when blended together, undergo a hardening reaction that involves neutralization of the acid groups by the powdered glass base.
Which is better zinc phosphate or zinc polycarboxylate?
Zinc phosphate cement has acceptable strength, working time and biological properties. It is easy to handle, even when mixing large quantities. Polycarboxylate cement has less strength, different flow properties and a shorter working time, but excellent biocompatibility.
Is zinc phosphate A permanent cement?
Zinc Phosphate Cement, a very high strength permanent cement, light yellow.
What is Zoe dentistry?
Eugenol-containing dental materials are frequently used in clinical dentistry. When zinc oxide-eugenol (ZOE) is applied to a dentinal cavity, small quantities of eugenol diffuse through the dentin to the pulp. Low concentrations of eugenol exert anti-inflammatory and local anesthetic effects on the dental pulp.
What is the main disadvantage of the zinc phosphate cement?
The advantages and disadvantages of zinc phosphate cement are set out in Table 12.4....Advantages and disadvantages.AdvantagesDisadvantagesEasy to mixPossibly irritant to the pulpSharp setDoes not bond to tooth tissue or restorative materialsAcceptable properties for purposeBrittleCheapNo antibacterial effects2 more rows•Jan 31, 2015
Is zinc phosphate cement safe?
Because of the phosphoric acid liquid, zinc phosphate cement is an irritant, and proper pulp protection is recommended.
What are some common uses for zinc phosphate?
It is commonly used for luting permanent metal and zirconium dioxide restorations and as a base for dental restorations. Zinc phosphate cement is used for cementation of inlays, crowns, bridges, and orthodontic appliances and occasionally as a temporary restoration.
What is zinc phosphate used for?
Zinc phosphate is used to produce corrosion resistant coatings that are typically applied either as part of an electroplating process or as a primer pigment. It reacts moderately with water and is acid soluble with zinc sources, allowing it to have good moisture resistance and galvanic substitution properties.
How long does it take for zinc phosphate cement to set?
The initial setting time of the zinc phosphate cement is around 5 minutes. The setting time depends upon numerous factors such as temperature, humidity, and particle size of the dental cement powder. The smaller particle size of the dental cement results in a faster setting of the dental cement.
Why is zinc phosphate cement weak?
Zinc phosphate cement forms a weak bond with the tooth structure because it does not form a chemical bond with the tooth structure. The bonding of zinc phosphate cement is by mechanical means similar to zinc oxide eugenol dental cement. The thermal conductivity of zinc phosphate cement is low. Therefore it is used as a cavity base ...
What is zinc phosphate?
The zinc phosphate dental cement is supplied in powder and liquid bottles. The zinc phosphate cement is also available in capsules in which the powder and liquid are Pre-portioned. The powder component of the dental cement comprises zinc oxide and magnesium oxide. While the liquid component comprises phosphoric acid and water.
What are the local adverse reactions of dental cement?
Local adverse reactions include cytotoxic reactions within the dental pulp. For example, after cementation of the prosthesis in young patients using zinc phosphate, cement produces cytotoxic reactions due to initial acidic pH during the setting of cement that may lead to pulp necrosis.
What is the setting reaction of zinc phosphate?
The setting reaction of zinc phosphate dental cement. The setting reaction is an acid-base reaction. The reaction occurs primarily between zinc oxide, which is the main ingredient of the powder and phosphoric acid, which is the main component of the liquid bottle.
Is zinc phosphate used in dental cement?
Although new dental materials are now available, zinc phosphate dental cement is still used for restorative applications.
Is glass ionomer cement antimicrobial?
The new materials, such as composite-based and glass ionomer cement, are now used for luting applications because of ease of use and better mechanical and esthetic properties. In contrast to other dental cement such as glass ionomer cement and zinc oxide eugenol cement, the zinc phosphate cement does not have any antimicrobial or therapeutic ...
What is zinc oxide cement?
Applications. Zinc oxide/eugenol cements. Supplied as two pastes or as a powder (zinc oxide) and liquid (zinc acetate, eugenol, olive oil) A slow chelation reaction of two eugenol molecules and one zinc ion to form zinc eugenolate without moisture. However, setting can be completed fast when water is present.
When was zinc polycarbonate invented?
Zinc polycarbonate was invented in 1968 and was revolutionary as it was the first cement to exhibit the ability to chemically bond to the tooth surface. Very little pulpal irritation is seen with its use due to the large size of the polyacrylic acid molecule. This cement is commonly used for the instillation of crowns, bridges, inlays, onlays, and orthodontic appliances.
What cement is used for amalgams?
Historically, zinc phosphate and polycarboxylate cements were used for this technique, however since the mid-1980s composite resins have been the material of choice due to their adhesive properties. Common resin cements utilised for bonded amalgams are RMGIC and dual-cure resin based composite.
What is dental cement used for?
Common uses include temporary restoration of teeth, cavity linings to provide pulpal protection, sedation or insulation and cementing fixed prosthodontic appliances. Traditional cements have separate powder and liquid components which are manually mixed ...
Why is cement used in restoration?
This is generally due to their reduced mechanical properties which may not withstand long-term occlusal load.
What is pulp capping?
Pulp capping is a method to protect the pulp chamber if the clinician suspects it may have been exposed by caries or cavity preparation. Indirect pulp caps are indicated for suspected micro-exposures whereas direct pulp caps are place on a visibly exposed pulp. In order to encourage pulpal recovery, it is important to use a sedative, non-cytotoxic material such as Setting Calcium Hydroxide cement .
What causes cement to fail?
Resistant to dissolution in saliva, or other oral fluid – a primary cause of cement failure is dissolution of the cement at the margins of a restoration.
What is the structure of magnesium ammonium phosphate cement?
Initially, the structure starts with poorly crystalline grains and develops into one containing plate-like crystals, which were identified as dittmarite and struvite. As the mass cures further, rod-like struvite crystals grow, indicating that struvite is the final crystal structure in this cement. A detailed study by Abdelrazig et al. [18] showed several typical characteristics of these rapid-setting cements:
What is the product of monoammonium phosphate?
As shown in Table 9.1, the main products of reaction of calcined MgO with monoammonium phosphate are struvite (MgNH 4 PO 4 ·6H 2 O) and schertelite [Mg (NH 4) 2 (HPO 4) 2 ·4H 2 O]. In the presence of sufficient water, the latter is converted to struvite by the reaction:
What are the mechanical properties of phosphosilicate ceramicrete?
The superior mechanical properties of phosphosilicate Ceramicrete may be attributed to the whisker form of the grains of wollastonite, which makes the composite a whisker-reinforced composite. Fig. 13.3 shows the scanning electron micrograph of a fractured surface of this ceramic. Each whisker in this case was ≈ 200 μm in length. These whiskers act as a second phase in the phosphosilicate Ceramicrete and deflect cracks during fracture of the ceramic, thus raising the fracture energy. This deflection of cracks may be seen in the figure. The result is an increase in the fracture toughness and the flexural strength.
How long does it take for calcium cement to set?
The authors use two commercial cements, one containing more calcium and the other containing a comparatively higher amount of alumina (or low calcium). The thickening times determined by consistency measurements (see Chapter 15) at 125°C show that setting started after 40 and 120 min respectively for high- and low-calcium cements.
How much compressive strength does a mortar have?
Mortars with less water showed higher strengths. For example, a solid-to-water ratio of 8 gave a compressive strength of 19.5 MPa (2790 psi) in 24 h, while the mortar made with a solid-to-water ratio of 16 attained strength of 27.4 MPa (3910 psi).
How long does MPP cement last?
MPP cements do not have classical induction (dormant) periods typical of Portland cements: the use of set retarders can extend the final set for days to weeks at a more or less constant rate.
What is cement used for?
The practical use of the cement takes advantage of rapid rate and magnitude of strength development. 265,268,269 Although these cements are mostly claimed to be dimensionally stable, a recently published review suggested that further investigation in this area might be necessary. 127 Apart from repair of civil engineering structures the cement has been used for encapsulation of nuclear waste. 270 The cement is usually blended with PFA or GGBS as filler materials, however, chemical interaction between the aluminosilicate phases of the two materials with the cement has been observed. 265
Dispensing Form and Composition of Zinc Phosphate Cement
The Setting Reaction
- The setting reaction is an acid-base reaction. The reaction occurs primarily between zinc oxide, which is the main ingredient of the powder and phosphoric acid, which is the main component of the liquid bottle. This setting reaction results in insoluble zinc phosphate, which is the set form of dental cement. The initial setting time of the cement is around 5 minutes. The setting time depe…
Properties
- Zinc phosphate cement forms a weak bond with the tooth structure because it does not form a chemical bond with the tooth structure. The bonding of cement is by mechanical means similar to zinc oxide eugenol dental cement. The thermal conductivity of cement is low. Therefore it is used as a cavity base under metallic restoration such as dental amalgam to protect the vitality of the …
Clinical Applications
- The zinc phosphate cement is used as a cavity liner and base material and has moderate durability. It has traditionally been used as a luting material for crown and bridge cementation. The esthetic properties, as already described, are not excellent, especially when the crown margins are visible. This cement is sometimes used as a temporary filling...
Adverse Reactions
- The systemic adverse effects are infrequent with the use of zinc phosphate cement. Local adverse reactions include cytotoxic reactions within the dental pulp. For example, after cementation of the prosthesis in young patients using this cement, it produces cytotoxic reactions due to initial acidic pH during the setting of cement that may lead to pulp necrosis. The young p…