en Prosthodontics Prosthodontics Original article Original article <div style="text-align: justify;"><span style="font-size:13pt"><span style="line-height:105%"><span new="" roman="" style="font-family:" times=""><b><span style="font-size:9.0pt"><span style="line-height:105%"><span style="font-family:" verdana=""><span style="color:#2e74b5">Background and Aim</span></span></span></span></b><b><span style="font-size:9.0pt"><span style="line-height:105%"><span style="font-family:" verdana=""><span style="color:#2e74b5">:</span></span></span></span></b> <span style="font-size:9.0pt"><span style="line-height:105%"><span style="font-family:" verdana="">Water sorption of provisional crown materials decreases their mechanical properties and longevity, depending on the material type. This study aimed to compare the water sorption of three provisional crown materials in vitro. &nbsp;</span></span></span>&nbsp;</span></span></span><br> <span style="font-size:13pt"><span style="line-height:105%"><span new="" roman="" style="font-family:" times=""><b><span style="font-size:9.0pt"><span style="line-height:105%"><span style="font-family:" verdana=""><span style="color:#2e74b5">Materials and Methods: </span></span></span></span></b><span style="font-size:9.0pt"><span style="line-height:105%"><span style="font-family:" verdana="">In this in vitro experimental study, 14 disc-shaped specimens measuring 1 x 15 mm were fabricated from Telio CAD polymethyl methacrylate (PMMA) computer-aided design-computer-aided manufacturing (CAD-CAM) block (Ivoclar Vivadent), self-cure PMMA acrylic resin (Tempron GC), and ProviTemp K acrylic-based composite resin (Provi Temp K). The specimens were randomly coded and their weight (with 0.0001 g accuracy) and volume (with 0.001 mm accuracy) were measured. The water sorption of the specimens was calculated after 7 and 30 days. One-way ANOVA was applied for data analysis (&alpha;=0.05). </span></span></span>&nbsp;&nbsp;</span></span></span><br> <span style="font-size:13pt"><span style="line-height:105%"><span new="" roman="" style="font-family:" times=""><b><span style="font-size:9.0pt"><span style="line-height:105%"><span style="font-family:" verdana=""><span style="color:#2e74b5">Results: </span></span></span></span></b><span style="font-size:9.0pt"><span style="line-height:105%"><span style="font-family:" verdana=""><span style="color:black">On day 7, the highest water sorption was noted in Bisco acrylic-based composite resin (mean: 22.84&plusmn;5.04 &micro;g/mm³) and the lowest water sorption was recorded in PMMA CAD-CAM block (mean: 14.22&plusmn;3.23 &micro;g/mm³) (P=0.023). At 30 days, the highest water sorption was recorded in Tempron GC self-cure acrylic resin (mean: 48.53&plusmn;18.44 &micro;g/mm³) and the lowest water sorption was noted in PMMA CAD-CAM block (mean: 40.24&plusmn;5.33 &micro;g/mm³) (P=0.002).</span></span></span></span><span style="font-size:9.0pt"><span style="line-height:105%"><span style="font-family:"Verdana",sans-serif"></span></span></span></span></span></span><br> <span style="font-size:13pt"><span style="line-height:105%"><span new="" roman="" style="font-family:" times=""><b><span style="font-size:9.0pt"><span style="line-height:105%"><span style="font-family:" verdana=""><span style="color:#2e74b5">Conclusion:</span></span></span></span></b> <span style="font-size:9.0pt"><span style="line-height:105%"><span style="font-family:" verdana=""><span style="color:#0e101a">The water sorption of Bisco acrylic-based composite resin and Tempron GC self-cure acrylic resin was very high in the short-term. However, after 30 days, the water sorption of Bisco acrylic-based composite resin and PMMA CAD-CAM block was the same.&nbsp; It appears that all three tested materials can provide acceptable clinical performance for the fabrication of provisional restorations.</span></span></span></span></span></span></span><br> &nbsp;</div> Acrylic Resins, Composite Resins, Dental Restoration, Temporary 210 217 http://jrdms.dentaliau.ac.ir/browse.php?a_code=A-10-1693-1&slc_lang=en&sid=1 Gholamreza Esfahanizadeh r.esfahanizadeh@yahoo.com 100319475328460015507 100319475328460015507 No Department of Prosthodontics, Faculty of Dentistry, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran. Farzan Younesi farzanunc@yahoo.com 100319475328460015508 100319475328460015508 No Department of Prosthodontics, Faculty of Dentistry, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran. Mohammadreza Hosseini kordkheili mohammadrezaho3eini@gmail.com 100319475328460015509 100319475328460015509 Yes Department of Prosthodontics, Faculty of Dentistry, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran. Hosein Akbari h.akbariiii75@gmail.com 100319475328460015510 100319475328460015510 No DDS, Private Practice, Tehran, Iran.