Introduction: Conventional techniques for closed hollow bulb obturators construction are technique sensitive, consume considerable amount of materials, and lack adequate control of the walls thickness of the bulb. Additionally, created sealing area is a potential site of leakage and discoloration. Digital technologies offer promising solutions to these drawbacks. Subtractive manufacturing systems are unable to produce hollow objects as one piece. In contrast, additive manufacturing systems can produce a hollow object in one piece.
Objectives: The aim of the present study was to evaluate one-piece closed hollow bulb obturators fabricated using CAD/CAM additive manufacturing and compare them to those constructed from heat cured resin.
Materials and methods: Six partially dentate patients with healed unilateral maxillary defects (Aramany's classes I or II) received two closed hollow bulb obturators. One constructed using CAD/CAM additive manufacturing, and another constructed from conventional acrylic resin. All patients' prostheses were evaluated for dimensional accuracy and intimacy of fit using digital measuring software package.
Results:CAD/CAM obturators showed negative dimensional change values when compared to the original design, while Heat-cured obturators showed positive ones. Generally, the highest values of deviations were recorded at occlusal units for CAD/CAM obturators (-0.34 ± 0.10) and Heat-cured obturators (0.21 ± 0.12) when fitting surface was used as reference. There were statistical significant differences in dimensional deviation between both obturator groups using two registration references. CAD/CAM obturators showed lower misfit values when compared to Heat-cured ones. The highest values of misfit were recorded at the oral extensions of the CAD/CAM (0.44 ± 0.27) and Heat-cured obturators (0.47 ± 0.32). However, there were no statistical significant differences between both obturator groups at any measured surface.
Conclusions: Additive manufacturing of obturators could be an alternative to conventional techniques for direct construction of one-piece closed hollow bulb obturators.