Research and EducationComparison of CAD-CAM and traditional chairside processing of 4-unit interim prostheses with and without cantilevers: Mechanics, fracture behavior, and finite element analysis
Section snippets
Material and methods
A nickel-chromium model simulating a 2-tooth edentulous space (second premolar and first mandibular molar) with abutments on the first premolar and second mandibular molar was used to fabricate 4-unit interim prostheses (N=40) (Fig. 1). A second similar nickel-chromium mandibular model with missing second premolar and second molar with abutments on the first premolar and first molar was used to fabricate 4-unit cantilever prostheses (N=40) with a cantilevered second mandibular molar pontic. The
Results
The mean values of maximum force required to fracture the conventional and cantilever interim prostheses are shown in Table 3. The interim prostheses processed by CAD-CAM showed the highest maximum force values: VITA CAD-Temp (3136 ±7.4 N) and Telio CAD (3126 ±165 N) (P=1.0). Dentalon Plus had a mean maximum force value approximately 60% lower (1390 ±82 N) than the highest maximum force values. The bis-acrylic showed the lowest mean of maximum load (1287 ±214 N), which was approximately 29%
Discussion
The present study combines the experimental mechanical testing, microscopic inspection, and biomechanical assessment of 4-unit interim prostheses with and without cantilevers. The results of this study revealed significant differences in maximum fracture force for the processing type or cantilever design; and therefore, the null hypothesis was rejected. Within the CAD-CAM processed materials, the VITA CAD Temp 4-unit prostheses withstood the highest maximum force values of about 3136 N followed
Conclusions
Based on the findings of this in vitro study, the following conclusions were drawn:
- 1.
Interim fixed partial prostheses produced by CAD-CAM had higher strength than those fabricated by traditional chairside polymerization.
- 2.
The traditional polymerization technique is susceptible to a low degree of polymerization and the occurrence of pore-like defects that could affect the strength of the prostheses.
- 3.
The presence of a cantilever negatively affected the strength of the test materials, although the
Acknowledgments
The authors thank the Dentalbasto laboratory for the support on the manufacturing of the specimens. Also, the authors acknowledge Prof Luis Moreira from the Deptartment for Quality Assurance and Office of Methodological Studies and Data Processing, Institute Jean Piaget, Portugal, for the statistical analyses.
CRediT authorship contribution statement
Carolina Coelho: Data curation, Writing - original draft. Catarina Calamote: Data curation, Writing - original draft. António Correia Pinto: Conceptualization, Supervision, Project
References (31)
- et al.
Fracture strength of temporary fixed partial dentures: CAD/CAM versus directly fabricated restorations
Dent Mater
(2011) - et al.
Comparison of the flexural strength and marginal accuracy of traditional and CAD/CAM interim materials before and after thermal cycling
J Prosthet Dent
(2014) - et al.
Comparison of interim restorations fabricated by CAD/CAM with those fabricated manually
J Prosthet Dent
(2015) - et al.
Fracture load of milled polymeric fixed dental prostheses as a function of connector cross-sectional areas
J Prosthet Dent
(2013) - et al.
Resin composite blocks via high-pressure high-temperature polymerization
Dent Mater
(2012) - et al.
Thickness of CAD-CAM composite resin overlays influences fatigue resistance of endodontically treated premolars
Dent Mater
(2009) - et al.
Energy dissipation capacities of CAD-CAM restorative materials: a comparative evaluation of resilience and toughness
J Prosthet Dent
(2019) - et al.
Fibre reinforcement of two temporary composite bridge materials - effect upon flexural properties
J Dent
(2012) - et al.
Fit of 4-unit FDPs made of zirconia and CoCr-alloy after chairside and labside digitalization - a laboratory study
Dent Mater
(2014) - et al.
Comparative study of interim materials for direct fixed dental prostheses and their fabrication with CAD/CAM technique
J Prosthet Dent
(2015)
Reinforcement of a PMMA resin for interim fixed prostheses with silica nanoparticles
J Mech Behav Biomed Mater
Influence of specimens' geometry and materials on the thermal stresses in dental restorative materials during thermal cycling
J Dent
Finite element analysis of stress extent at peri-implant bone surrounding external hexagon or Morse taper implants
J Mech Behav Biomed Mater
Biomechanical simulation of temporomandibular joint replacement (TMJR) devices: a scoping review on the finite element methods
Int J Oral Maxillofac Surg
In vitro study of fracture strength of provisional crown materials
J Adv Prosthodont
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Supported by FCT (Fundação para Ciência e Tecnologia) in the subject of projects: POCI-01-0145-FEDER-031035_LaserMULTICER.