Impact Of Humidity On Accuracy Of Surgical Guides

To evaluate the impact of storage humidity and time on the accuracy of 3D printed implant surgical guides with Digital Light Processing (DLP) technology. The implant surgical guides used in the study were designed for a case of Kennedy Class I edentulism. 18 surgical guides were printed at three group (n=6), according various build angles (0°, 45°, and 90°), and then each group were divided into two subgroups(SP1 & SP2), and stored in two different humidity (SP2: humidity 18.8%, SP2: humidity 92.4%). The three-dimensional data of the guides were obtained using an intraoral scanner immediately after printing and subsequently scanned every seven days. Deviation analysis was conducted using Geomagic Control X software to calculate the RMS values and standard deviations. Data were analyzed by One-way ANOVA (α = 0.05) and bivariate correlation test. The build angles significantly affected the accuracy of the guides (P<0.05), with the initial RMS value being the lowest in the 0° group (0.052±0.003mm) and the highest in the 90-degree group (0.128±0.007mm). After 56 days of storage under high-humidity conditions(SP2), the RMS value of the 90° group increased by 32.5%, significantly higher than that of SP1 group (P<0.01). This in vitro study conclusively demonstrates that ambient humidity exceeding 90% induces statistically significant dimensional deviations in 3D-printed surgical guides, establishing precise humidity control during storage of surgical guides as a factors in maintaining implant surgical accuracy.