Publications by authors named "Patcharanun Chaiamornsup"

2 Publications

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Effects of build orientation on adaptation of casting patterns for three-unit partial fixed dental prostheses fabricated by using digital light projection.

J Prosthet Dent 2021 Feb 26. Epub 2021 Feb 26.

Professor, Department of Oral Biomaterials Engineering, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.

Statement Of Problem: The lost-wax technique is commonly used for fabricating partial fixed dental prostheses. The casting patterns can be fabricated by using vat photopolymerization (a type of additive manufacturing), but the adaptation of these casting patterns has not been elucidated.

Purpose: The purpose of this in vitro study was to evaluate the effect of build orientation on the adaptation of casting patterns fabricated by digital light projection (DLP).

Material And Methods: A 3-unit partial fixed dental prosthesis with mandibular left second premolar and second molar abutment teeth was scanned and virtually designed with a computer-aided design software program. The cement space was designed to be 30 μm. Specimens were fabricated with 3 build orientations: 0 degrees (with the occlusal surface parallel to the platform), 30 degrees, and 45 degrees (by rotating the file along the long axis). The casting patterns were fabricated by using DLP (Cara Print 4.0) with a photopolymerizable monomer (dima Print Cast Q). Photopolymerization, cleaning, and postpolymerization processes were performed according to the manufacturer's instructions. The adaptation of the specimens was examined by using a silicone replica method. The vertical marginal discrepancy and axial wall, occlusal, and marginal gaps were measured by using a digital measuring microscope. The effect of build orientation at each cross-sectional area was statistically analyzed by using the Kruskal-Wallis test followed by the pairwise Wilcoxon rank sum test with Bonferroni correction (α=.05).

Results: Excess polymerized resin was observed along the intaglio buccal wall at build orientations of 30 degrees and 45 degrees. Vertical marginal discrepancies in the buccolingual section ranged from -50 to 248 μm, while those in the mesiodistal section ranged from -25 to 182 μm. The gaps in the buccolingual section ranged from 0 to 236 μm, while those in the mesiodistal section ranged from 0 to 177 μm. According to the observation of vertical marginal discrepancies and gaps, the 30-degree specimens inclined during insertion, and the 45-degree specimens were not completely seated. However, the marginal gaps of the 0- and 30-degree specimens were within the clinically acceptable limit of 120 μm.

Conclusions: The limited data indicated that the build orientation influenced the adaptation of casting patterns for 3-unit partial fixed dental prostheses fabricated by using DLP. A build orientation of 0 degrees is recommended for fabricating casting patterns for 3-unit partial fixed dental prostheses because no excess polymerization of the intaglio buccal wall was observed.
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http://dx.doi.org/10.1016/j.prosdent.2021.01.006DOI Listing
February 2021

Effects of build conditions and angle acuteness on edge reproducibility of casting patterns fabricated using digital light projection.

Dent Mater J 2020 Jan 2;39(1):135-140. Epub 2019 Oct 2.

Department of Oral Biomaterials Development Engineering, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University.

The aim of the present study was to evaluate the effects of build conditions and angle acuteness on edge reproducibility of the casting patterns fabricated using a digital light process. The prism-shaped patterns with various vertex angles were fabricated in three build orientations. The height from the base to the vertex angle point of the fabricated pattern was measured and the incomplete height was calculated as the discrepancy between the original and measured heights. Two-way ANOVA revealed that the vertex angle and build orientation and their interaction were significant (p<0.05). The incomplete height significantly decreased with an increase of the vertex angle. When the vertex angle was 20° and the build-up direction was parallel to the edge of vertex angle and perpendicular to the triangular base, the incomplete height was the smallest. Therefore, build orientation and angle acuteness influenced the edge reproducibility of the casting patterns fabricated using a digital light process.
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http://dx.doi.org/10.4012/dmj.2018-401DOI Listing
January 2020