Table 6.

Characteristics of various fibers used for the mechanical reinforcement of PMMA.

Fiber type	Characteristic Description and Main Outcomes	Reference
Carbon	Enhancement of the mechanical properties, including tensile strength, flexibility, fracture resistance, and elastic modulus.	[20,242]
	Reduced thermal expansion of modified PMMA materials.	[20]
	Poor aesthetic properties due to the color of fibers.
Aramid (Kevlar)	Polyamide fibers that have better wettability (coupling pre-treatment is not required) and improved mechanical properties, such as fracture resistance.	[243]
	Poor aesthetics due to yellowish color; fibers exposed to the surface are irritable to patient’s tissues. Difficult to finish and polish the surface.	[18,75,244]
	Increasing the concentration of fibers reduced the hardness.	[18,75]
Nylon	Adding nylon fibers improved the flexural strength.	[245]
	Improved structural elasticity and fracture resistance.	[103]
Polyethene and polypropylene	Adding surface-treated fibers improved the impact strength.	[21,139]
	Superior toughness and ductility.	[22,246,247]
	In addition to impact strength, adding silanized fibers improved the tensile and transverse strengths of heat-cured PMMA, however wear resistance was poor.	[17]
	The aesthetic properties were not affected due to their white color.	[21,243]
	Technique was sensitive and required surface treatment, therefore is not used extensively.	[243]
Glass	Glass fibers can be used in various forms (woven, loose); provide excellent reinforcement and aesthetics compared to other fibers.	[245]
	A remarkable increase in the denture base toughness, Vickers hardness, impact strength, and flexural strength was observed.	[15,16,248,249]
	A remarkable reduction in the deformation (<1%).	[15]
	The silanized glass fibers enhanced the flexural strength, while the strength of modified PMMA may be influenced by the proportion and positioning of fibers.	[19]