Thermoplastic fibre-reinforced composites for dentistry

Jančář, J.; Dibenedetto, A. T.; Goldberg, A.

doi:10.1007/bf00125594

Cited by 21 publications

(5 citation statements)

References 20 publications

(13 reference statements)

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“…The appearance of cracks is the sign of plastic deformation of the wire and later loss of force. This result is in agreement with Jancar et al 30 who affirmed that the possible factors that contraindicate the use of polymer-and fiber-based esthetic wires are in the transverse fractures, fractures due to stress with detachment of the fibers, fractures at the polymer-fiber bond surface, compressive fracture arising from bends located in the fibers, and fractures close to the surface.…”

Section: Discussionsupporting

confidence: 92%

Comparison of the Load Deflection Characteristics of Esthetic and Metal Orthodontic Wires on Ceramic Brackets using Three Point Bending Test

Doshi

Mahindra

2013

J Indian Orthod Soc

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Objectives: To compare the load deflection of orthodontic wires with round section of 0016" made of stainless steel (SS), nickel-titanium (NiTi) and glass fiber-reinforced polymer composite (GFRPC). Materials and methods: A total of 60 specimens were obtained from the posterior arches of 30 precontoured trademark TP Orthodontics (La Porte, Indiana) wires and were divided into three groups of 20 according to each type of material and length of 50 mm. The methodology consisted of a 3-point bending test using esthetic ceramic brackets (INVU-TP Orthodontics, Standard Edgewise, 0.022" × 0.025") as points of support. The tensile tests were performed on a mechanical test machine, EMIC model DL500 (São José dos/SP), at a speed of 10 mm/min, deflection of 1, 2 and 3 mm. Results: GFRPC wires had lower strength values among all groups evaluated (statistically significant, p < 0.05). The NiTi wire presented smaller load/deflection compared with SS. The steel wire showed permanent deformation after 3 mm deflection, NiTi wire demonstrated memory effect and the esthetic type had fractures with loss of strength. Conclusion: Steel wires showed highest strength values, requiring the incorporation of loops and folds to reduce the load/deflection. NiTi and GFRPC wires produced more deflection at low levels of force, however the esthetic wire was shown to fracture and break.

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Section: Discussionsupporting

confidence: 92%

Comparison of the Load Deflection Characteristics of Esthetic and Metal Orthodontic Wires on Ceramic Brackets using Three Point Bending Test

Doshi

Mahindra

2013

J Indian Orthod Soc

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“…In order to vary layer thickness, the deposited layer was treated with SiCl 4 and then additional layers were deposited to give layers of overall desired thickness. Based on the previous results [2,3], PC layers were tested both as deposited and annealed for 10 min at 245 • C. Interphases deposited without using SiCl 4 served as a reference.…”

Section: Methodsmentioning

confidence: 99%

Thickness dependence of elastic modulus of polycarbonate interphase

Jančář

2008

Composite Interfaces

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The oligomer of bis-phenol A (oligo-PC) with M w = 1300 and bis-phenol A polycarbonate (PC) with M w = 20 000 were deposited onto E-glass surface using SiCl 4 as the grafting and cross-linking agent. Thickness of the deposited layers was varied from 30 to 10 6 nm and the layers were investigated as prepared and after thermal annealing at 245 • C for 10 min in the air. Vibrational piezoelectric resonator technique and the speed of Rayleigh wave measurement were used to determine elastic moduli of the ultra thin layers deposited on flat E-glass substrate as a function of their thickness. In all cases, increase of the Young modulus of the interphase, E i , with decreasing layer thickness, t i , was observed. At a given thickness, the E i of PC layer was significantly lower than that for the oligo-PC layer. Thermal annealing of the deposited PC layer resulted in a significant increase of its E i compared to the as received layer. No significant change was observed for oligo-PC interphases. Increase of the shear strength of the interface, τ a , with reducing interphase thickness, t i , was observed.The observed increase of E i with the decreasing t i was ascribed to the reduction of the molecular mobility of chains near solid surface compared to their mobility in the bulk. Most probably, the observed increase of E i after thermal annealing of PC was caused by rearrangement of both segment density distribution in individual PC coils near the solid surface and cooperative rearrangements of multiple PC chains. Since the oligomers attached to the surface attained presumably more regular extended conformations with lower conformation entropy compared to the PC random coils, the effect of thermal annealing was negligible. In agreement with theoretical predictions, increase of E i at the same extent of interfacial interactions resulted in the observed increase of the τ a measured using the single embedded fiber test.

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“…Moreover, PCA/bare E-glass fiber composite annealed at 275 °C for 1 h before immersion in water exhibited superior resistance to moisture attack. Resistance against moisture favours the application as an orthodontic wire of this material [248]. Table 6 is a summary of PCA based devices used for dentistry.…”

Section: Polycarbonatesmentioning

confidence: 99%

“…Table 6 is a summary of PCA based devices used for dentistry. [245] Thermoplastic PCA denture base resin [246] PCA based fiber-reinforced composites [247] PCA/bare E-glass fiber composite [248] 7.6.6. Polyurethanes…”

Section: Polycarbonatesmentioning

confidence: 99%