Behavior of PMMA Denture Base Materials Containing Titanium Dioxide Nanoparticles: A Literature Review

Table 1

TiO₂NP applications in denture base and its effect on the tested properties.

Authors /year	Particle size	Addition percentage	Type of Acrylic	Nanocomposite preparation	Properties tested	Specimen size	Effects (Increase/Decrease/Unchanged)
Chatterjee, 2010 [9]	5 nm	0%-15wt%	PMMA from Scientific Polymer Products (Ontario, NY)	(i) Measured TiO2NP mixed with PMMA for 5-10 min; (ii) DACA twin-screw extraction process at 190°C and 100 rpm.; (iii) Acrylic mixed for 6-7 min and extruded 5 times	(i) Tensile modulus; (ii) Dimensional stability; (iii) Glass transition temperature (); (iv) UV absorption	10 x 6 x 0.3 mm; 5 mg	(i) Improvement in tensile modulus.; (ii) Increased thermal stability; (iii) Increased; (iv) Improvement in UV absorption maximum at 2% TiO2NP
Chatterjee, 2010 [10]	5 nm	0%; 2.0%; 5.0%; 7.5%; 10.0%; 15.0%; 30.0%	PMMA from Scientific Polymer Products (Ontario, NY)	(i) Measured TiO2NP mixed with PMMA for 5-10 min; (ii) DACA twin-screw extraction process at 190°C and 100 rpm.; (iii) Acrylic mixed for 6-7 min and extruded 5 times	(i) Glass transition temperature (); (ii) Thermal stability; (iii) Decomposition temperature	10 x 6 x 0.3 mm	(i) increased linearly up to 7.5% TiO2NP.; (ii) Thermal stability increased (2%-15% TiO2NP); (iii) Decomposition temperatures increased with filler content up to 10% TiO2NP.
Anehosur et al., 2012 [11]	31 nm; “Anatase phase”	3.0%; In addition to surface coating.	DPI heat cure acrylic resin, (India)	(i) Visible light activated TiO2NP were mixed with methyl methacrylate monomer.	(i) Microbial inhibitory effect against S. Aureus	5 x 5 x 2 mm	(i) 3w% of TiO2 shows antimicrobial activity against S. Aureus.
Sodagar et al., 2013 [12]	21 nm; “Anatase phase”	0%; 0.5%; 1.0%	Selecta Plus (self-cure acrylic resin)	(i) TiO2NP were added to acrylic monomer.	(i) Flexural strength	50 x 10 x 3.3 mm	(i) Flexural strength decreased as the filler content increased.
					(i) Flexural modulus		(i) No change in flexural modulus.
Hamouda and Beyari, 2014 [13]	21 nm	5.0%	Conventional heat cure acrylic resin (Acroston, WHN, England) and high impact (Metrocryl Hi, Metrodent, LTD, England)	(i) TiO2NP were mixed thoroughly with acrylic powder by hand.	(ii) Flexural strength; (iii) Toughness	65 x 10 x 2.5 mm	(ii) Flexural strength and toughness decreased.
					(iv) Monomer release		(iii) No difference between control and TiO2 reinforced regarding monomer release.
Nazirkar et al., 2014 [14]	7 nm; “Anatase phase”	0%; 0.5%; 1.0%	DPI heat cure acrylic resin	(i) TiO2NP added to acrylic monomer.	(i) Flexural strength	65 x 10 x 3.3 mm	(i) Flexural strength decreased as the TiO2 amount increased.
Shirkavand and Moslehifard, 2014 [15]	<25 nm; (average ~ 20.4 nm); “Anatase and Rutile phases”	0%; 0.5%; 1.0%; 2.0%	Heat cure acrylic resin from Ivoclar Vivadent	(i) TiO2NP were mixed with the acrylic resin polymer in an amalgamator for 20 min.	(i) Tensile strength	60 x 12 x 4 mm	(i) Tensile strength and elastic modulus improved with 1% TiO2NP.; (ii) 0.5% and 2% TiO2 were not significantly different from each other or control.
Harini et al., 2014 [16]		0%; 1.0%; 2.0%; 5.0%.	Clear heat cure acrylic resin	(i) Nanoparticles were incorporated into monomer by ultrasonic dispersion.	(i) Flexural strength	65 x 10 x 3 mm	(i) Flexural strength improved with TiO2 addition, significant difference noticed with 5%.
Safi, 2014 [17]		5.0%	Heat cure denture base acrylic (Superacryl plus, Czechoslovakia)	(i) Nanoparticles added to monomer and sonically dispersed.	(i) Coefficient of thermal expansion; (ii) Modulus; (iii) Glass transition	15 x 6 mm; Cylinders; 65 x 10 x 2.5 mm; Powder form (10g)	(i) Decrease in coefficient of thermal expansion.; (ii) Decreased in modulus of elasticity; (iii) Increased
Alwan, and Alameer, 2015 [18]	<50 nm size	0%; 3.0%; (i) Silanized with TMSPM	Heat cure acrylic resin	(i) Silanized TiO2NP were added to monomer and sonicated.	(i) Impact strength; (ii) Transverse strength; (iii) Hardness; (iv) Surface roughness; (v) Water sorption and solubility	80 x 10 x 4 mm; 65 x10 x 2.5 mm; 50 x 0.5 mm disc	(i) Increased; (ii) Increased; (iii) Increased; (iv) Increased; (v) Decreased
Ahmed et al., 2016 [19]	46 nm	0%; 1.0%; 5.0%	Conventional heat cure acrylic resin (Implacryl, Vertex) and high impact heat cure acrylic resin (Vertex-Dental, Netherlands)	(i) TiO2NP were added into acrylic resin.	(i) Flexural strength; (ii) Impact strength; (iii) Hardness	50 x 10 x 3 mm; 60 x 6 x 4 mm; 25 x 10 x 3 mm	(i) Decreased with TiO2 addition.; (ii) Increased only for conventional acrylic resin modified by 1%.; (iii) Increased with 5% addition TiO2NP for both types of acrylic.
Sodagar et al., 2016 [20]	21 nm	0.5%; 1.0%	Selecta Plus (self-cure acrylic resin)	(i) Nanoparticles were added to acrylic monomer and stirred	(i) Antimicrobial properties	20 x 20 x 1 mm	(i) TiO2 reduced microbial growth at both concentrations at 90 min under UVA exposure; (ii) Antimicrobial activity of TiO2 is time dependent
Ahmed et al., 2017 [21]	<25 nm	0%; 0.5%; 1.0%	Heat cure acrylic resin from Dentsply International Inc., (Chicago, IL, USA)	(i) TiO2NP were added to acrylic polymer and mixed using amalgam capsule.	(i) Flexural strength; (ii) Fracture toughness; (iii) Hardness	65 x 10 x 2.5 mm; 65 x 10 x 2.5 mm; 30 x 10 x 2.5 mm	(i) Increased with both filler percentages.; (ii) No effect on fracture toughness of both filler percentages.; (iii) Increased with 1% filler.
Hashem et al., 2017 [22]	90 nm	0%; 1.0%; 2.0%; 3.0%	Self-cure acrylic resin from Eco-crylcold,; Protechno, (Spain)	(i) TiO2NP were mixed with the monomer.	(i) Flexural modulus and flexural strength; (ii) Hardness; (iii) Surface wetting	30 x 8 x 1 mm; 50 x 1 mm discs	(i) Increased linearly; (ii) Increased.; (iii) Reduced with 1% filler content and increased with higher percentages.; (iv) decreased with TiO2 addition
Ghahremani et al., 2017 [23]	20-30 nm; “Anatase phase”	0%; 1.0%	SR Triplex Hot, heat cure acrylic resin (Ivoclar Vivadent Inc. Schaan, Liechtenstein)	(i) TiO2NP were mixed with acrylic resin powder in an ultrasonic mixer.	(i) Tensile strength; (ii) Impact strength	60 x 12 x 3.9 mm; 75 x 10 x 10 mm	(i) Increased; (ii) Increased
Totu et al., 2017 [24]	65-170 nm	0%; 0.2%; 0.4%; 1%; 2.5%	PMMA+PEMA for 3D printing (eDent 100, EnvisionTec GmbH Gladbeck, Germany)	(i) Nanoparticles were added into PMMA solution with continuous stirring and ultrasonic mixing for 1 hour.	(i) Antimicrobial effect (Candida scotti); (ii) Complete denture manufacturing using stereolithography		(i) 0.4, 1% and 2.5% inhibited candida growth; (ii) PMMA/0.4%TiO2 composite successfully used for denture fabrication
Aziz, 2018 [25]	30 nm	0%; 3.0%	High impact heat cure acrylic resin (Vertex-Dental, Netherlands)-	(i) TiO2NP were dispersed in monomer and sonicated at 120W and 60 KHz for 3 minutes.	(i) Impact strength; (ii) Color stability; (iii) Thermal conductivity	80 x 10 x 4 mm; 35 x 15 x 0.5 mm; 40 x 2.5 mm	(i) Increased; (ii) Increased color stability for test groups; (iii) No effect
Alrahlah et al., 2018 [26]	80-100 nm	0%; 1%; 2%; 3%	Heat cure acrylic resin (Lucitone 550, Dentsply Int. Inc. Pa, USA)		(i) Hardness and modulus; (ii) , degradation temperature and rate; (iii) Creep-recovery and relaxation behavior; (iv) Antibacterial adhesion	50 x 10 mm discs cut in different sizes for different tests; 7 mg; 5 x 10 mm	(i) Increased; (ii) Slight increase with 2% nano-filler content; (iii) Improvement in behavior; (iv) Decrease in bacterial attachment content
Karci et al., 2018 [27]	13 nm	0%; 1%; 3%; 5%	(i) Auto-polyerized (Heraeus Kulzer, Newbury; Berkshire, UK); (ii) Heat-polymerized Heraeus Kulzer, Newbury; Berkshire, UK.; (iii) Microwave-polymerized (GC Dental, Tokyo, Japan)	(i) TiO2NP were mixed with acrylic resin powder using ball milling at 400 rpm for 2 hours	(i) Flexural strength	65 x 10 x 3 mm	(i) Increased for heat- and auto-polymerized acrylic at 1%; (ii) Decreased for all types of acrylic at 5%
Totu et al., Totu et al., 2017 [28]	“Anatase phase”	0%; 0.2%; 0.4%; 0.6%; 1.0%; 2.5%	(i) PMMA-MA; (ii) PMMA-MMA-BPO; (iii) 3D printed PMMA (eD, EnvisionTec GmbH Gladbeck, Germany)	(i) TiO2 modified by methacrylic acid then manually mixed with PMMA mixture	(i) Thermal stability; (ii)	Stereolithographic dentures	(i) Increased (improved); (ii) Increased
Totu et al., 2018 [29]	“Anatase phase”	0%; 0.2%; 0.4%; 0.6%; 1.0%; 2.0%; 2.5%; 5.0%	PMMA for 3D printing (eDent 100, EnvisionTec GmbH Gladbeck, Germany)		(i) Resistance; (ii) Electrical conductivity; (iii) Dielectric constant		(i) Decreased with 1.0%, 2.0%, 2.5% and 5%; (ii) Increased but material still maintained insulating properties; (iii) Increased with 5%