Comparison of fracture strength after thermo-mechanical aging between provisional crowns made with CAD/CAM and conventional method

Abstract

PURPOSE. The objectives of this study were to evaluate the fracture strength and fracture patterns of provisional crowns fabricated from different materials and techniques after receiving stress from a simulated oral condition. MATERIALS AND METHODS. A monomethacrylate-based resin (Unifast Trad) and a bis-acryl-based (Protemp 4) resin were used to fabricate provisional crowns using conventional direct technique. A milled monomethacrylate resin (Brylic Solid) and a 3D-printed bis-acrylate resin (Freeprint Temp) were chosen to fabricate provisional crowns using the CAD/CAM process. All cemented provisional crowns (n=10/group) were subjected to thermal cycling (5,000 cycles at 5°-55ºC) and cyclic occlusal load (100 N at 4 Hz for 100,000 cycles). Maximum force at fracture was tested using a universal testing machine. RESULTS. Maximum force at fracture (mean ± SD, N) of each group was 657.87 ± 82.84 for Unifast Trad, 1125.94 ± 168.07 for Protemp4, 953.60 ± 58.88 for Brylic Solid, and 1004.19 ± 122.18 for Freeprint Temp. One-way ANOVA with Tamhane post hoc test showed that the fracture strength of Unifast Trad was statistically significantly lower than others (P<.01). No statistically significant difference was noted among other groups. For failure pattern analysis, Unifast Trad and Brylic Solid showed less damage than Protemp 4 and Freeprint Temp groups. CONCLUSION. Provisional crowns fabricated using the CAD/CAM process and the conventionally fabricated bis-acryl resins exhibited significant higher fracture strength compared to conventionally fabricated monomethacrylate resins after the aging regimen. Therefore, CAD/CAM milling and 3D printing of provisional restorations may be good alternatives for long term provisionalization.

Does Printing Orientation Matter? In-Vitro Fracture Strength of Temporary Fixed Dental Prostheses after a 1-Year Simulation in the Artificial Mouth

“…A vertical load of 98 N representing applied forces during mastication was applied [ 16 ]. This is consistent with comparable studies [ 17 ]. Additionally, each loading cycle included a lateral movement by means of a 0.5 mm side shift with the applied load of the antagonist.…”

“…For the standardized fabrication of three-unit FDPs, the upper right first molar (tooth 16, according to the FDI scheme) was removed from a phantom model (KaVo Dental, Biberach, Germany), and the upper right second premolar (15) and second molar (17) were prepared with a circular chamfer of 0.8 mm and an occlusal reduction of 1.5 mm. This situation was digitized with a model scanner (inEos X5, inLab software, Dentsply Sirona), and a three-unit FDP was designed following the recommended settings of the inLab software for the fabrication of long-term temporaries out of inCoris PMMA blanks.…”

Strategic Use of CAD-CAM Interim Restoration for the Recovery of the Vertical Dimension of Occlusion in the Posterior Partially Edentulous Jaw

“…Afterward, the crown design was modified in accordance with the newly established vertical dimension with digital techniques, and then converted to monolithic zirconia using the milling method. The use of CAD allowed the application of modifications according to functional and aesthetic demands [20]. Image replacement of the abutments using the image superimposition technique enhanced the marginal fit of the definitive restorations.…”

“…Long-term use of interim restorations is necessary during the course of treatment using oral implants or in situations involving comprehensive occlusal reconstruction [19,20]. Since the introduction of computer-aided design and computer-aided manufacturing (CAD-CAM) to dentistry by Duret et al [21], CAD-CAM has become an alternative to the conventional methods used for fabricating fixed interim restorations [22].…”

“…Alp et al [25] showed high flexural strength in CAD-CAM interim polymers than in the bis-acrylate composite resin and conventional acrylic resin. Reeponmaha et al [20] mentioned the use of CAD-CAM-fabricated high-density interim restorations enabled predictable and easier results in the prolonged pretreatment phase.…”