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Orthodontic thermoformed retainers: a two‐arm laboratory study into post‐fabrication outcomes
Author(s) -
Doğramacı EJ,
Chubb DWR,
RossiFedele G
Publication year - 2018
Publication title -
australian dental journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.701
H-Index - 71
eISSN - 1834-7819
pISSN - 0045-0421
DOI - 10.1111/adj.12610
Subject(s) - thermoforming , materials science , fabrication , retainer , copolyester , molar , composite material , dentistry , medicine , polyester , alternative medicine , pathology
Background Retainers are commonly used to maintain post‐orthodontic occlusion stability. We aimed to determine post‐fabrication thickness and thinning rate of thermoformed retainers. Methods Forty‐eight retainers were fabricated from polyethylenterepthalat‐glycol copolyester or polypropylene blanks, using vacuum‐ or pressure‐thermoforming. Retainer thickness was measured at multiple locations. Results Thinning rate had a broad range: the mid‐labial incisor region of 1 mm polyethylenterepthalat‐glycol copolyester pressure‐thermoformed mandibular retainers had the greatest thinning rate (68.25 ± 8.26%) and smallest mean post‐fabrication thickness (0.32 ± 0.08 mm). Polyethylenterepthalat‐glycol copolyester retainers were 0.11 mm thinner than polypropylene ( P =0.0222), and polypropylene retainers were 0.21 mm thicker, when pressure‐thermoformed ( P <0.0001). The interaction of manufacturing method and material used, and tooth type, explained over a third of the variability in the post‐fabrication thickness of these retainers. Maxillary retainers made from 1 mm blanks were 0.04 mm thicker in the incisor region compared with the molar region ( P =0.0492). Conclusions Thermoformed retainers do no thin uniformly against individual teeth and have variable intra‐ and inter‐arch post‐fabrication thicknesses. There is no clear benefit in using a specific type of thermoforming machine or material for increasing post‐fabrication thickness or reducing thinning rate. Blank thickness and tooth morphology influence these outcomes.