Abstract Purpose The purpose of this in vitro study was to investigate the effect of alcohol‐free cleaning solutions on the mechanical properties and reliability of additively manufactured occlusal device resins, compared with isopropyl alcohol (IPA), while considering the influence of aging. Materials and Methods Bar‐shaped (64×10×3.3 mm) specimens were additively manufactured from two occlusal device resins (Freeprint Splint 2.0; FS, KeySplint Hard; KS) and divided into three groups based on the cleaning solution used (IPA, methylether solvent (MES), and a water‐based solution) ( N = 30). After postprocessing, each set of specimens was further divided into two groups based on their aging condition as nonaged or aged ( n = 15). Specimens in nonaged subgroups were tested for 3‐point flexural strength and microhardness, while those in aged subgroups were subjected to 5000 thermal cycles between 5°C and 55°C before testing. Both data sets were analyzed with a generalized linear model either with a normal distribution and identity link function (microhardness) or a gamma distribution and logarithmic link function (flexural strength). The maximum likelihood estimation method was used for the Weibull analysis of the flexural strength data and further evaluated with the chi‐squared test ( α = 0.05). Results Aged KS had higher flexural strength than its FS counterpart when IPA and MES were used ( P ≤ 0.014). MES led to the lowest flexural strength for aged FS, which had lower values than nonaged FS when MES and the water‐based solution were used ( p ≤ 0.002). Nonaged MES‐cleaned KS had lower hardness than its FS counterpart ( p <0.001). Water‐based solution led to higher hardness than MES for aged KS, and aged KS had higher hardness than nonaged KS when the water‐based solution and MES were used ( p ≤ 0.028). KS mostly had higher reliability than FS; MES use tended to result in lower reliability among the aged specimens, and aging reduced the reliability of MES‐cleaned FS and KS specimens as well as of FS specimens cleaned with a water‐based solution ( p ≤ 0.027). Conclusions Flexural strength, microhardness, and reliability of the KS resin were mostly similar to or better than those of the FS resin. Cleaning with MES or aging may compromise mechanical properties and reliability, depending on the resin.
Polat et al. (Fri,) studied this question.