Wear comparison of thermoplastic materials used for orthodontic retainers

Gardner, Gary; Dunn, William J.; Taloumis, Louis J.

doi:10.1016/s0889-5406(03)00502-x

Cited by 66 publications

(63 citation statements)

References 9 publications

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“…Gardner et al 15 reported that the mean wear in the Essix C+ group was 5.9 mm, in the Invisacryl C group it was 6.1 mm, and in the TR group it was 1.6 mm. The TR group (polyethylene copolymer) demonstrated significantly less wear than the two polypropylene groups.…”

Section: Discussionmentioning

confidence: 99%

“…The laboratory study by Gardner et al 15 described in the introduction is the only published study the authors have found investigating the wear properties of VFRs. In that study, the authors tested three different VFR products, two of which were polypropylene polymersEssix C+ and Invisacryl C-while the third was a polyethylene copolymer, TR.…”

Section: Discussionmentioning

confidence: 99%

“…Estimates for sample size determination were obtained from the paper by Gardner et al 15 To detect a minimum clinical difference of two units with a standard deviation of 2.4, assuming a significance level of 5% (a 5 .05) and 80% power, the study needed to have 26 specimens per group.…”

Section: Sample Sizementioning

confidence: 99%

“…In that study, Gardner et al 15 assessed three different VFR products for their resistance to wear: two of the materials were polypropylene polymers, whereas the third was a polyethylene polymer. The samples underwent 1000 cycles of wear under a load of 25 kg using an Instron machine, with steatite balls as the antagonist material.…”

Section: Introductionmentioning

confidence: 99%

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Wear resistance of four types of vacuum-formed retainer materials:A laboratory study

Raja¹,

Littlewood²,

Munyombwe³

et al. 2014

The Angle Orthodontist

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Objective: To investigate the resistance to wear of four different vacuum-formed retainer (VFR) materials: Essix C+, Essix ACE, Duran, and Tru-Tain. Essix C+ is a polypropylene polymer; the other materials are polyethylene co-polymers. Materials and Methods: The study was undertaken at the Leeds Dental Institute, Leeds, UK, with 26 samples in each group. The specimens were vacuum-formed according to the manufacturers' guidelines, and a custom-made wear-simulation machine was used to conduct the test. Each specimen was subjected to 1000 cycles of the wear simulation, with steatite balls as the antagonist material. The resistance to wear of the VFR materials was evaluated by measuring the maximum wear depth using noncontact, three-dimensional surface profilometry. The wear depth was given in micrometers.Results: The median wear depth was 63.20 mm for the Essix C+ group, 7.88 mm for the Essix ACE group, 9.75 mm for the Duran group, and 12.08 mm for the Tru-Tain group. The Kruskal-Wallis test to compare the four VFR materials detected a statistically significant difference between the groups (P , .001). Comparisons of the groups using the Mann-Whitney U-test demonstrated that the Essix C+ group had significantly greater wear than the other three groups (P , .001). There was no statistically significant difference in median wear depth between the two groups with the least amount of wear-the Essix ACE and Duran groups. Conclusions: Under the standardized conditions of this laboratory study, the three polyethylene co-polymer materials-Essix ACE, Duran, and Tru-Tain-exhibited significantly less wear than the polypropylene material, Essix C+. (Angle Orthod. 2014;84:656-664.)

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Sample Sizementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Wear resistance of four types of vacuum-formed retainer materials:A laboratory study

Raja¹,

Littlewood²,

Munyombwe³

et al. 2014

The Angle Orthodontist

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“…To date, only two studies have evaluated the properties of orthodontic thermoplastic retainers. Gardner et al 1 compared the wear resistances of three different retainer thermoplastics and found that when they are placed in water and rubbed with a weighted steatite abrader, polyethyleneterephthalate-glycol (PETG) thermoplastics exhibited greater resistance to wear than did two polypropylenebased thermoplastics. In a study of eight different retainer thermoplastics, Ryokawa et al 2 found that aging for 24 hours in 37uC distilled water (DW) reduced tensile yield strengths compared with specimens that had not been thermoformed and with specimens that were thermoformed and stored dry.…”

Section: Introductionmentioning

confidence: 99%

The Essential Work of Fracture of Thermoplastic Orthodontic Retainer Materials

Pascual¹,

Beeman²,

Hicks³

et al. 2010

The Angle Orthodontist

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Objective: To investigate whether oral cleansing agents affect the essential work of fracture (EWF) and plastic work of fracture (PWF) for two types of orthodontic thermoplastic retainer materials. Materials and Methods: Polyethylene-terephthalate-glycol (PETG; Tru-Tain Splint) and polypropylene/ethylene-propylene rubber (PP-EPR) blend (Essix-C+) sheets were compared. For each material, six sets of 25 sheets were thermoformed into double-edge-notched-tension specimens; subsets of five specimens were formed with internotch distances (L) equal to 6, 8, 10, 12, or 14 mm, respectively. Sets were stored (160 hours, 25uC) in air (DRY), distilled water (DW), Original Listerine (LIS), mint Crest ProHealth (CPH), 3% hydrogen peroxide (HP), or Polident solution (POL). Specimens were fractured in tension at 2.54 mm/min. Areas under load-elongation curves were measured to determine total work of fracture (W f ). Linear regressions (W f vs L [n 5 25]) yielded intercepts (EWF) and slopes (PWF). Ninety-five percent confidence intervals were used to evaluate differences in EWF and PWF estimates. Results: PP-EPR blends showed higher EWFs after storage in HP vs storage in DW. PP-EPR blend showed higher EWFs after storage in CPH vs PETG. After HP storage, PP-EPR exhibited lower PWFs than with any other storage conditions. PP-EPR exhibited higher PWFs than PETG after storage in DRY, DW, and LIS. Conclusions: Compared with DW, none of the cleansers decreased the energy to initiate fracture. With one exception, no cleanser decreased the energy to continue plastic fracture extension. In PP-EPR blend, increased resistance to fracture initiation was observed with CPH and HP, yet, surprisingly, HP decreased resistance to plastic fracture growth. (Angle Orthod. 2010;80:554-561.)

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