This study will compare the dimensional discrepancies of functional casts obtained using conventional custom trays and 3D-printed custom trays made from PET-G (Polyethylene Terephthalate Glycol) filament. Thirty completely edentulous maxillary patients treated in the Complete Denture Course at the School of Dentistry, University of São Paulo (FOUSP), will be evaluated. Anatomical casts will be obtained, digitized, and used to fabricate conventional or digitally designed and 3D-printed custom trays. Functional impressions will then be made with zinc-oxide eugenol impression paste, and the resulting functional casts will be fabricated in Type III gypsum. The casts will be digitized and compared using 3D metrology software. Measurements will be obtained at standardized anatomical regions, including the bilateral tuberosity regions, incisive papilla, palatine raphe, and four vestibular points.
Complete denture fabrication commonly relies on long-established conventional techniques. Custom trays are conventionally fabricated with chemically activated polymethyl methacrylate (PMMA) acrylic resin. Digital dentistry and additive manufacturing may provide alternative methods and materials for custom-tray fabrication, including PET-G (Polyethylene Terephthalate Glycol) filament. In this study, functional casts obtained using conventional custom trays will be compared with functional casts obtained using digitally designed and 3D-printed custom trays. Anatomical casts will be made according to the anatomical impression technique fabricated in Type II gypsum, and digitized with an INEOS X5 bench scanner. The digital models will be processed in inLab software to remove undercuts and define the basal area outline. For the conventional group, custom trays will be fabricated with chemically activated PMMA acrylic resin. For the printed group, custom trays will be digitally designed with a thickness of 3 mm and zero spacing, exported as STL files, and printed on an Adventurer 4 Pro printer using CREALITY CR-PETG thermoplastic filament, according to the manufacturer's parameters. Functional impressions will be obtained using the technique recommended by the FOUSP Complete Denture Course and zinc-oxide eugenol impression paste. Functional casts will be fabricated in Type III gypsum, scanned, and exported as STL (Standard Triangle Language) files. The meshes will be compared in ZEISS Inspect software to quantify discrepancies between the test and reference meshes.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
DIAGNOSTIC
Masking
NONE
Enrollment
30
Participants or casts associated with the conventional technique will be evaluated. The anatomical model will be delineated according to the FOUSP Complete Denture Course and isolated with a gypsum-resin separator. Chemically activated PMMA acrylic resin will be manipulated at a ratio of 15 cc powder to 5 cc liquid, adapted to the model in the plastic phase, and finished and polished after complete polymerization.
Participants or casts associated with the printed technique will be evaluated. The custom tray will be digitally designed using inLab software with a thickness of 3 mm and zero spacing. The STL file will be printed on an Adventurer 4 Pro printer using CREALITY CR-PETG thermoplastic filament, according to the manufacturer's parameters. The tray will then be finished and polished.
Three-dimensional discrepancy between functional-cast STL meshes
Difference between the STL meshes of the functional casts obtained using conventional PMMA custom trays and the functional casts obtained using PET-G filament 3D-printed custom trays. Mesh discrepancy will be quantified in ZEISS Inspect software using standardized anatomical measurement points. The measurements will be performed using the deviation label tool (inspect\>deviation label) and collected in mm. The measurement locations will include the bilateral tuberosity regions, palatine raphe region, incisive papilla region, and four vestibular points.
Time frame: After completion of both functional impressions, up to 4 weeks after the first functional impression.
Regional three-dimensional mesh discrepancy at standardized anatomical points
Regional differences between the STL meshes will be measured at eight standardized points: two points in the tuberosity regions, one point in the palatine raphe region, one point in the incisive papilla region, and four vestibular points.
Time frame: After completion of both functional impressions, up to 4 weeks after the first functional impression
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