Comparative Assessment of Polymerization Techniques on the Fit Accuracy of Acrylic Resins Fabricated by CAD-CAM Milling, 3D Printing, and Microwave Processing

Abstract

Aims: Poly-methyl-methacrylate resin has been used commonly for denture bases. Polymerization shrinkage
and release of thermal stresses are the major disadvantages exhibited of these materials Till date, no research
is there in literature comparing the adaptation accuracy microwave acrylic resin cured by microwave energy
and resin cured by CAD-CAM milling and 3D Printed technique The present study was conducted to check
the effect of curing mode on the adaptation accuracy of CAD-CAM Milled, 3D Printed and microwave
processed acrylic resin.
Materials and Method: A master cast was duplicated to obtain 36 gypsum casts. In the computer-aided
design and computer-aided manufacturing (CAD/CAM) groups (milling and 3-D printing), the 24 gypsum
casts from two groups were scanned. An STL file was obtained and a master complete denture base was
designed and then fabricated according to each technique . In the conventional group, a polyvinyl siloxane
putty Mold was obtained from the milled complete denture base, and this Mold was used to fabricate 12
microwave processed acrylic resin by microwave energy The base/cast sets were sectioned transversally in the
posterior palatal seal zone. The measurements were made at the right marginal limit, left marginal limit, right
ridge crest, left ridge crest and the palatal midline. The existence of gaps between the casts and acrylic was
assessed using a stereomicroscope.
Results: The mean marginal discrepancy at Right marginal limit, left marginal limit, Right Ridge crest, Left
Ridge crest and Palatal midline was significantly more in microwave resin samples cured by microwave
energy (500 W for 3 min) in comparison to resin samples cured by CAD- CAM 3D Printed Technique. The
mean marginal discrepancy at, right marginal limit, left marginal limit, Right Ridge crest, Left Ridge crest and
Palatal midline was significantly more in microwave resin samples cured by microwave energy (500 W for 3
min) in comparison to resin samples cured by CAD–CAM milling Technique.
There was no significant difference at, right marginal limit, left marginal limit, Right Ridge crest, Left Ridge
crest and Palatal midline of dimensional discrepancy between resin samples cured by either CAD-CAM
milling or 3D Printed technique.
Conclusion: It is evident that resin denture base produced by CAD-CAM milling or 3D Printed technique
produced the minimal adaptation discrepancy.
Clinical Significance: CAD-CAM milling or 3D Printing technique can be adopted for fabrication of the
complete denture bases.