Vip Call Girls Anna Salai Chennai 👉 8250192130 ❣️💯 Top Class Girls Available
Glass Ionomer Cements.pdf
1. Lesson 7. Glass ionomer cements.
Classification, composition, properties, indications for use, preparation method,
representatives.
Rinat Bayburin
Department of Therapeutic Dentistry
Krasnoyarsk State Medical University
2. Glass ionomer cements
it is a class of dental materials created by combining the properties of
silicate and polyacrylic systems.
3. I. Classification by application
I type. Glass ionomer cements for fixation (luting).
II type. Restorative glass ionomer cements for permanent fillings:
• a) aesthetic;
• b) hardened. Cermets are silver-modified cements.
III type. Fast hardening glass ionomer cements:
• a) for gaskets (lining and basic);
• b) fissure sealants.
IV type. Glass ionomer cements for root canal filling.
4. II. Classification by the form of release
• Powder-liquid.
The powder in such cements consists of finely ground aluminofluorosilicate glass with all the necessary additives, the liquid is an
aqueous solution of a copolymer of carboxylic acids with the addition of 5% tartaric acid.
• Powder.
In such cements, all components are in powder, mixed with distilled water. This group of glass ionomer cements is called Aqua-
cements. The advantages of Aqua-cements are: ease of mixing, ease of transportation and storage, increased shelf life. The
disadvantage is high initial acidity, which can lead to higher postoperative sensitivity compared to other glass ionomer cements.
• Capsules.
The advantage of this form of release is that the powder and liquid are packaged in capsules in the required ratio, therefore, when
mixed, cement with optimal properties is obtained.
• Paste.
Produced in tubes or syringes. Cements of this form of release do not require mixing, are easy to use, harden with a halogen lamp.
5. III. Depending on the chemical composition and curing mechanisms
1.Traditional (classical) glass ionomer cements are a powder-liquid system and have only one chemical method of
hardening by the type of acid-base reaction.
Disadvantages:
- low strength;
- fragility;
- high abrasion;
- high solubility during the first days after application;
- sensitivity to excess and lack of moisture during the entire period of hardening until complete maturation of the cement;
- possible toxic effect on the dental pulp;
- long time of final hardening;
- the possibility of the appearance of microcracks and the delay of the pickling acid during overdrying;
- poor polishability.
6. III. Depending on the chemical composition and curing mechanisms
2. Hybrid glass ionomer cements (glass ionomer cements modified with polymer). A polymer resin is
included in this group of cements, and they have a double (chemical and light) or triple curing mechanism.
Hybrid glass ionomer cements have a number of advantages over traditional cements:
- ease of use;
- fast hardening;
- resistance to moisture and overdrying;
- the possibility of immediate processing;
- higher mechanical strength;
- a stronger bond with the tooth tissues.
7. Hybrid glass ionomer cements
In deep areas that are not accessible to the light of the photopolymerizer, where curing
occurs only due to the glass ionomer reaction, the strength of the material is lower.
To avoid this, it is advisable to use a layer-by-layer technique of applying glass
ionomer cement, which somewhat complicates the work with it.
The solution to the problem was the development of triple-hardened hybrid glass
ionomer cements (Vitremer material (3M, 1994).
After kneading and placing the filling, exposure to light (30 sec.) Causes a rapid curing
of the material to the depth of light penetration. If the material is not exposed to light, it
will self-cure within 15-20 minutes.
8. IV. Classification by polymerization technique:
• self-affirming,
• light-curing,
• combined (double, triple curing).
9. V. Classification by the form of release:
• water systems,
• waterless systems,
• semi-aquatic systems.
10. Positive properties of GIC
1. Chemical adhesion to tooth tissues. The strength of adhesion of glass
ionomer cements to enamel and dentin is relatively low (2-7 MPa).
2. Chemical adhesion to various filling materials. Due to chelating and
hydrogen bonds, glass ionomer cements form chemical adhesion with
composites, stainless steel, gold and platinum compounds, oxidized foil, and
materials containing eugenol.
11. Positive properties of GIC
3. Anti-carious activity is provided due to the prolonged release of fluorine from
the cement mass into the environment. This process begins immediately after
filling (reaches a maximum after 24-48 hours, and sharply decreases after
24-79 hours) and lasts up to 3 years.
4. Sufficient mechanical strength and elasticity. Glass ionomer cements have
high compressive strength. In addition, they have a low modulus of elasticity
(Young's modulus), i.e. high elasticity. These properties allow them to withstand
occlusal loads under fillings, inlays and crowns. To some extent, glass
ionomers are able to compensate for the polymerization shrinkage of the
composites, as well as the stresses that arise in the cervical region during
microbending of the tooth during chewing.
12. Positive properties of GIC
5. Low thermal conductivity. Of all dental filling materials, glass ionomer cements
have the lowest thermal conductivity, this property of glass ionomer cements helps
to minimize the harmful thermal effects on the dental pulp (≈ 0.198 mm2 / s).
6. Satisfactory aesthetic properties make glass ionomer cements the material of
choice in those clinical situations where the use of a composite for any reason is
impossible.
7. High biological compatibility, non-toxicity and no irritating effect on the dental
pulp. The high biocompatibility of JIC allows them to be used without insulating liners
or as a cushioning material in the treatment of moderate caries, however, in case of
deep caries, it is necessary to use a medical cushion based on calcium hydroxide.
13. Positive properties of GIC
8. Relatively low shrinkage. Compounds 1.0 + 3.6No after 30 sec. After
application and 2.8-7.1% - after 24 hours. Shrinkage is observed, if the cement
is overdried, water absorption compensates for the shrinkage inherent in GIC.
9. Color stability. They are explained by the better bonding between the matrix
and the glass compared to that between the filler and the resin in the
composite.
10.Ease of use. This factor is important in the treatment of children, as well as in
other situations when the patient is physically unable to sit motionlessly with his
mouth open for a long time necessary to fulfill all the requirements of the
“composite technology”.
14. Positive properties of GIC
11.Radiopacity.
12.Relatively low cost. The low price with a completely satisfactory quality of
fillings makes glass ionomer cements the main materials when providing
"free" dental care to low-income segments of the population, when placing
fillings on teeth with a dubious prognosis (for example, with severe
periodontitis), when filling milk teeth, etc.
15. Disadvantages of GIC
For all its positive qualities, traditional GIC are difficult to work with, they have a number of disadvantages:
• high viscosity, low plasticity;
• early sensitivity to premature moisture ingress and overdrying;
• short working time, fast setting;
• insufficient strength (cannot be used in areas with a high chewing load);
• low resistance to abrasion and porosity, which leads to poor surface polishing;
• long final hardening reaction (24–48 hours);
• high initial acidity;
• insufficient chemical resistance.
16. Indications for use
• filling of cavities of III and V classes in permanent teeth;
• Class II carious cavities with tunnel filling;
• class I caries with a small size of the carious cavity;
• root caries;
• creation of the basis for the restoration (sandwich technique);
• erosion and wedge-shaped defects of permanent teeth;
• filling of cavities of all classes of temporary teeth;
• sealing (sealing) fissures;
17. Indications for use
• as an insulating pad;
• as a temporary filling for a long period (from 6 - 12 months to 2 years) with
delayed endodontic treatment (apexogenesis, apexification);
• filling of root canals with gutta-percha pins;
• fixation of the post in the root canal;
• fixation of orthopedic structures (inlays, crowns);
• fixation of orthodontic structures.
18. Basic rules for working with glass ionomer cements
1. The dissection of a carious cavity differs from the classical Black scheme:
• there is no need for prophylactic excision of healthy tissue;
• no need to create retention points, notches;
• it is not necessary to create a bevel of the enamel, only to finish;
• wedge-shaped defects and erosion are not prepared, cleaned from plaque with an
abrasive paste;
• in deep cavities, the application of a therapeutic paste based on calcium hydroxide
is used.
19. Basic rules for working with glass ionomer cements
2. When choosing a shade of material, take into account the darkening of the
filling during hardening.
3. Conditioning:
• 10 - 25% polyacrylic acid solution;
• 10 - 15 s to remove the smear layer and activate calcium and phosphate ions.
4. Gentle drying, do not overdry (JIC-hydrophilic material).
20. Basic rules for working with glass ionomer cements
5. Kneading:
• on a smooth glass surface or on special paper 30-60 s;
• plastic spatula (JRC is glued to the metal);
• powder is added to the liquid in two portions;
• each portion is kneaded for 20 seconds.
6. Application of the material is preferably with plastic tools.
• Working time - on average 2 minutes.
21. Basic rules for working with glass ionomer cements
7. Setting time:
• fixing cements - 4 - 7 min,
• laying cements - 4 - 5 min,
• reduction cements - 3 - 4 min.
8. The seal is isolated from the oral fluid with a special varnish.
9. The final processing of the filling is done after 24 hours.
22. Mixing
Glass ionomer (traditional) cements are kneaded on a dry smooth surface of
glass or special paper (plastic) at a temperature in the working room of 18-23 °
C. The required portion of the powder is usually divided into two equal parts.
First, the first part of the powder is added to the liquid, kneaded for 15-20 s until
a homogeneous mass is obtained, then another part of the powder is added to it
and the whole material is kneaded until a homogeneous mass with a glossy
surface is obtained. The average mixing time is 30-45 seconds.
23. AQUA CEMENTS
Characteristic Name
Fixing
Aqua Meron (Voco), Cem Base (Ihde Dental), Lonofix
(Voco), Lonoscell (Septodont).
Recovery
Aqua Ionofil, Argion (Voco), ChemFill Superior (De Trey /
Dentsply), ChemFill II (De Trey / Dentsply).
Interlining
Stion-APH, Tsemion-APH (Vladmiva), Aqua Ionobond
(Voco), Base Line (De Trey / Dentsply).
For filling root canals Endion (Voco), Stiodent (Vladmiva).
