poor hygiene can cause severe and progressive erosion in conventional GI restoration |
In dentistry there
is a continuous need for change in techniques and materials, depending on the change
in demand from the professional perceptions of patients and with technological
advancement. With time, dentists alter their perspective to establish awareness
among the public that removing dental caries is not merely a mechanical method
but an approach to noninvasive technique and that there are more possibilities
for advancement. [1]
Modification of glass ionomer cements
Successive
modifications were made to regular GIC to overcome their mechanical integrity
insufficiency and their ability to resist fracture loads. Thus, in addition to
the high viscosity ionomer cements, and those with integration of
nanoparticles, several materials have emerged with different composition such
as glass ionomer cements reinforced with metal or modified with resin. All
these changes were made to meet individual clinical needs and improve GICs'
physicochemical properties. There's been efforts for several years to
incorporate fibers as reinforcing agents into structure of these materials. But
there are differences in powder-liquid ratio and particle size to satisfy the
feature desired [4].
Hainomers
These are new and
innovative bioactive materials developed by integration of hydroxyapatite into
glass ionomer powder. They are primarily used in oral maxillofacial surgery as
bone cements, and may be used in the future as retrograde filling materials. They
play a part in bonding directly with the bone and influencing its growth and
development [6].
Bioactive glass (BAG)
The incorporation of alumina fibers into GIC's glass powder helps to boost GIC's flexural strength. This technology is called Inorganic Matrix Material, Polymeric Rigid. It's a light-hearted GIC. It involves the incorporation into the powder of continuous alumina network scaffold and SiO2 ceramic fibers. This increases the cure depth, reduces the shrinkage in polymerization, improves wear resistance and increases the set cement's flexural strength. [9]
Zirconomer
A new class of
restorative GIC is being established with increased strength and durability, it
shows strength of amalgam so it is also called white amalgam.
Nanotechnology in
GICs
1. Powder-modified nano-glass ionomers: first defined
by De Caluwé et al. [12], it involves doping traditional GICs with nano-sized
glass particles that can minimize setting time and increase compression
strength and elastic frame. The main advantages of lower setting times of
direct restore materials are increased ease of handling.
Nano bio-ceramic impregnated GIC
It is
well-documented that the integration of nano-sized particles in powder-modified
nano-glass ionomers enhances its mechanical properties. De Caluwé et al has
shown that doping conventional GICs with nano-sized glass particles can reduce
setting time and increase compression strength and elastic-modulus. Improving
the mechanical properties adds to GIC's quality and reliability and shelf-life,
as they can more easily tolerate the masticatory and occlusal forces. Adding
apatite to GIC powder increases the GIC set's crystallinity and thus, enhances
chemical stability and water insolubility [10].
Nano-ionomer
Nowadays,
nanotechnology has been implemented in the dental field, also known as
molecular nanotechnology or molecular engineering, offering a cosmetically
acceptable reconstruction with excellent mechanical and physical properties. A
new generation of glass ionomer cements modified in resin (RMGICs) was
introduced in 2007. The manufactures describe Ketac nano (3 M ESPE) as
(nano-ionomer). Nanotechnology incorporation in these materials enhances its
physical properties [13]. Nanoiomer blends nanofillers and clusters of
particles from the fluoroaluminosilicate glass to enhance color characteristics
and polishability. This new resin-modified nano-filled glass ionomer
restorative material was introduced into permanent teeth to restore permanent
teeth and small cavities. It is based on the same manufacturer's (Vitremer)
resin-modified glass ionomer with a simplified dispensing and mixing system
that requires the use of a priming step, but no separate conditioning step. Its
primary healing mechanism is by activating light, and no redox or self-healing
occurs during setting. This system allows for the integration of a highly
packed filler material, of which about two thirds are nanofillers. The fluoride
release profile of the modified glass ionomer cement with nano-filled resin is
similar to that of the RMGIC [4].
Addition of titanium dioxide nanoparticles
The addition of
apatite and titanium nanotubes to resin-based cements has been found to
increase fracture toughness, flexural strength and compressive strength, as
well as resin-based cements' hardness and elasticity modulus, without altering
their radiopacity or biocompatibility [14]. In 2011, Elsaka et al evaluated the
effect of adding titanium dioxide nanoparticles to conventional glass ionomer
cement in 3, 5 and 7wt percent ratios. In contrast to unmodified glass ionomer
cement, they found that glass ionomer cement containing 3 and 5wt percent
titanium dioxide nanoparticles showed improved fracture toughness, flexural
strength and compression strength. However, for glass ionomer cement containing
7wt per cent titanium dioxide nanoparticles, a decrease in mechanical
properties was found. Glass ionomer containing nanoparticles containing 5 and
7wt per cent titanium dioxide had reduced surface micro hardness. Time
arrangement of glass ionomer nanoparticles containing titanium dioxide was
approved. The application of titanium dioxide nanoparticles to modern GIC did
not weaken its frequency of bonding with dentin or its release of fluorides.
Compared with the unmodified glass ionomer, glass ionomers containing TiO2
nanoparticles processed the most potent antibacterial activity against
streptococcus mutants [4,15] .
Not only is glass ionomer bioactive, but it also has
characteristics of an intelligent substance. Glass-ionomer can be called active
as it releases fluoride, it can be called smart because it releases fluoride in
proportion to the acidity. It has a buffer capacity of pH to some extender.
Their brittleness and poor wear resistance are common problems of modern
glass-ionomers. Even the latter is pH-dependent, meaning proper oral hygiene is
vital. Unlike resin bonding, glass-ionomer's adhesion to tooth structure is not
sensitive to technique, and its performance increases with time. Their constant
urge for innovations in dentistry stems from changing professional perceptions
and changing patient demands with increasing awareness that dental caries
treatment is not just a technique, but also requires a less invasive
bio-medical approach. In the course of its inception, this new family of GIC
restorative materials has held many nifty facets and still hold the baton in
the never-ending quest for excellence in clinical dental research. GIC will
make everything happen. With the introduction of nanotechnology into GIC to
improve its mechanical properties, it can be concluded that commercially
available nano-RMGICs have no substantial advantage or disadvantage over conventional
restorative materials in terms of surface mechanical properties.
References
1.AlOtaibi G.
Recent advancements in glass ionomer materials with introduction of
nanotechnology: A review. International Journal of Oral Care and Research. 2019
Jan 1;7(1):21.
2. Wilson AD and Kent BE. “A new
translucent cement for dentistry. The glass ionomer cement”. British
Dental Journal 132.4 (1972): 133-135.
3. Tyas MJ and Burrow MF. “Adhesive
restorative materials: a review”. Australian Dental Journal 49.3 (2004):
112-154.
4. Bakhadher W. Modification of Glass
Ionomer Restorative Material: A Review of Literature. EC Dental Science.
2019;18:1001-6.
5. Davidson CL. Advances in glass-ionomer cements. Journal of Applied Oral
Science. 2006;14(SPE):3-9
6. Dhoot R, Bhondwe S, Mahajan V, Lonare S, Rana K. Advances in Glass
Ionomer Cement (GIC): A Review.
7. Maryam Khoroushi, Fateme Keshani. A
review of glass ionomers: From conventional glass ionomer to bio active. J.
dent res 2013:10:4:411-420.
8. Piekar C, Rajnikanth S. An In-Vitro
assessment of role of tooth mousse in preventing wine erosion. Aust Dent J
2008:53:22-5
9.Aishwarya Sharma, Mausmi Singh, Vinisha
Pandey.Glass Ionomer Cement-A Phoenix and its new flight. Int J of Research in
Health and Allied Sciences 2015:1:1:9-12.
10. Srikumar GP, Elsa N, Mookambika R, Agrawal A. Newer advances in glass
ionomer cement: A review. Annals and Essences of Dentistry. 2016
Dec;8(4):19-23.
11. NajeebáS, KhurshidáZ, ZafaráMS, KhanáAS,
ZohaibáS, MartÝáJM, etáal. Modifications in glass ionomer cements: Nano-sized
fillers and bioactive nanoceramics. Int J Mol Sci 2016;17:1134.
12..Deá CaluwÚá T, Vercruysseá CW, Fraeymaná S,
Verbeecká RM. The influence of particle size and fluorine content of aluminosilicate
glass on the glass ionomer cement properties. Dent Mater 2014;30:1029-38.
13.Coutinho E., et al. “Bonding
effectiveness and interfacial characterization of a nano-filled resin-modified
glass-ionomer”. Dental
Materials 25.11 (2009): 1347-1357.
14.Elsaka SE., et al. “Titanium
dioxide nanoparticles addition to a conventional glass-ionomer restorative:
Influence on physical andantibacterial properties”. Journal of Dentistry 39.9 (2011): 589-598.
15. Mitra SB., et al. “An
application of nanotechnology in advanced dental materials”. Journal
of the American Dental Association 134.10(2003): 1382-1390.
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