Vat photo-polymerized denture marking plate processed with a three-dimensional printer

Abstract

A simple processing technique for a denture marking plate is reported. An outline of the rectangular plate was designed with a three-dimensional (3D) software. The alphanumeric size was set at approximately 2-mm in height. The current case printed telephone code number, abbreviation of university, and prefectural code, with 0.75-mm in depth. The alphanumeric groove was filled with white colored opaque resin. The plate was inserted into the denture base with an acrylic repair resin. The numbers and letters were clearly visible through the acrylic resin material. This method is applicable to varying sizes of marking plates placed on partial dentures.

Introduction

Several methods have been reported for marking personal identification on removable dentures, i.e., implanting a printed sheet [1,2], and metal identification strips with laser marking [3,4]. The marking includes the patient’s name [5], the United States Social Security number [6], British Dentists Register [7], international telephone code [8], abbreviation of clinic [8], and prefectural code [8], [supplement]. Methods to embed micro secure digital (SD) cards [2], near-field communication (NFC) tags [9,10] and quick response (QR) codes [1,3,4] have also been reported. However, there have been few reports about the fabrication of marking plates with well-defined characters, the size of which can be freely changed. This article reports on a method for manufacturing personal identification marking plates processed with vat photo-polymerization.

Materials and Methods

Equipment and materials

The equipment and materials used are listed in Table 1. A three-dimensional (3D) printer (Saturn 8K, Elegoo, Shenzhen, PR China) was used to produce acrylic marking plates by means of masked stereolithography (MSLA). A light-polymerizable denture base material (DH Print Denture Base, Denken-Highdental, Kyoto, Japan) was selected in the fabrication of marking plates. A light polymerizable opaque resin (Cesead N Opaque, Kuraray Noritake Dental, Tokyo, Japan) was used to fill the 3D printed concave numbers and letters. An auto-polymerizing acrylic resin (Provinice, Shofu, Kyoto, Japan) was used for installation of the marking plate.

Technical procedure

The size of the marking plate was set at 20 × 3 × 1.5 mm, and the numbers and letters printed were 81NUSD13 with 0.75 mm in depth. The current case printed the international telephone code of Japan 81, abbreviation of the university hospital NUSD, and Japanese prefectural code of Tokyo 13. The slicer software setup for a total of 90 layers was 0.05 mm per one-layer. The detailed specification is as follows: layers 1-60, support platform; layers 61-75, plate section; and layers 76-90, plate with concave letter section.

• • The plate was designed with computer-aided design (CAD) software (Tinkercad, Autodesk, Tokyo, Japan) (Fig. 1a).
• • Standard tessellation language (STL) data were converted to Gemster Code (G-code) by means of the Slicer software (Chitubox, Shenzhen CBD Technology, Shenzhen, PR China) (Fig. 1b).
• • The G-code was delivered to the Saturn 8K 3D printer.
• • A light-polymerizable denture base material (DH Print Denture Base, Denken-Highdental) was stirred at 50°C for 10 min using a heat mixer (3D Photopolymer Resin Heated Mixer, Shenzhen SMP 4D Technology, Shenzhen, PR China) (Fig. 1c).
• • The heated flowable material was placed in the 3D printer, in which the model is converted to the marking plates.
• • The created model was vat photo-polymerized with 405 nm visible light irradiation (Fig. 1d).
• • The polymerized marking plates were cleaned for 10 min in an ultrasonic bath with 95-vol% ethanol (Fig. 1e).
• • The secondary polymerization of marking plates was performed for 10 min with a light-emitting diode (LED) polymerization unit (α-Light V, J. Morita, Suita, Japan) (Fig. 1f).
• • After polymerization, the excess material was trimmed with a rotary cutting instrument.
• • The printed concave numbers and letters were filled with the Cesead N opaque resin, cleaned with a brush, and wiped off with alcohol gauze (Fig. 2a-c).
• • The opaque resin was polymerized with the LED polymerization unit for 5 min.
• • The palatal surface of the removable partial denture was cut away in order to place the marking plate (Fig. 3a).
• • The marking plate was embedded with Provinice acrylic resin, pressurized and polymerized with a low-temperature heat oven.
• • The excess resin material was cut with a rotary instrument, and buff-polished (Fig. 3b-d).

Table 1 Equipment and materials employed

Equipment / Trade name	Manufacturer / Trader	Specification
Three-dimensional (3D) printer
Saturn 8K	Elegoo, Shenzhen, PR China	stereolithography: masked stereolithography (MSLA), light source: chip on board (COB) 405 nm, XY axis resolution: 0.0285 mm, Z axis accuracy: 0.00125 mm, layer thickness: 0.01-0.2 mm, printing speed: 30-70 mm/h, voltage range: 100-240 V 50/60HZ, 24 V, 5 A, 120 W
Heat mixer
3D Photopolymer Resin Heated Mixer HM100	Shenzhen SMP 4D Technology, Shenzhen, PR China	input voltage: DC 24 V, 2.0 A
Polymerization unit
α-Light V	J. Morita, Suita, Japan	blue light emitting diode × 33, violet light emitting diode × 15, wavelength: 465-475 nm, 400-408 nm
pressurized low-temperature heat oven (trade name unavailable)	Shofu, Kyoto, Japan	motor: single phase 100 V, electric power consumption: 600 W, operating pressure: 0.39 N
Material / Trade name	Manufacturer / Trader	Lot number	Composition*
Light-polymerizable denture base material
DH Print Denture Base Standard Pink	Denken-Highdental, Kyoto, Japan	E3463938	methacrylic acid ester, others
Coloring material
Cesead N Opaque A2O	Kuraray Noritake Dental, Tokyo, Japan	1N0010	Bis-GMA, TEGDMA, glass filler, photoinitiator, others
Autopolymerizing acrylic resin
Provinice 8S	Shofu	062143	MMA, EMA, others
Provinice liquid	Shofu	092185	MMA, others

Fig. 1 Design and fabrication of marking plate with 3D printer

Fig. 2 Coloring of marking plates

Fig. 3 Embedding marking plate into removable partial denture

Results

Figure 2d-f show the printed plates both before and after coloring. The numbers and letters were originally designed with a depth of 0.75 mm. The depth of the printed numbers and letters, measured with a micrometer, was 0.73 mm. The numbers and letters were precisely molded with an error of 0.02 mm, and the reproducibility was satisfactory. As shown in Fig. 2e-f, the 3D printer is capable of printing numbers and letters with different depth and length-to-width ratios.

Discussion

The plate size can be controlled by applying opaque material to the concave portion of the plate to make the numbers and letters clearer. This step makes it possible to produce small marking plates applicable to the limited area of partial dentures. The technique reported in the current article is applicable to the fabrication of marking plates with identical numbers and letters, or design information. A laboratory technique for making an individual’s information with very small-sized numbers and letters needs to be considered further.

Abbreviations

3D: three-dimensional; Bis-GMA: bisphenol-A glycidyl dimethacrylate; CAD: computer-aided design; COB: chip on board; EMA: ethyl methacrylate; G-code: Gemstar Code; LED: light-emitting diode; MMA: methyl methacrylate; MSLA: masked stereolithography; NFC: near-field communication; QR: quick response; SD: secure digital; STL: standard tessellation language; TEGDMA: triethyleneglycol dimethacrylate

Ethical Statements

Not applicable

Conflicts of Interest

Not applicable

Funding

Supported in part by a grant from the Japanese Dental Science Federation, JDSF-DSP1-2024-301-1

Author Contributions

HI: conceptualization, methodology, data curation, visualization, writing, review, and editing; HH: conceptualization, investigation, methodology, data curation, visualization, writing, review, and editing; TY: methodology, writing, review, editing, and supervision. All authors read and approved the final version of the manuscript.

ORCID iD

• 1) HI*: [e-mail], https://orcid.org/0009-0009-4569-4978

  2) HH: [e-mail], https://orcid.org/0000-0002-1328-6648

  2) TY: [e-mail], https//orcid.org/0000-0003-1029-4439

Acknowledgments

The authors express their appreciation to C. S. Langham for proofreading the manuscript.

Data Availability Statements

Data generated and analyzed are available from the corresponding author on reasonable request. Supplementary material is available at J-STAGE Data, doi: 10.60355/data.apjod.27273618.

• 1) References reported on denture marking up to 1980s

References

• 1. Rojas-Torres J, Cea M, Zhu YJ, Fonseca GM. Behavior of 4 types of paper with printed QR codes for evaluating denture marking in conditions of extreme heat. J Prosthet Dent 2022; 127: 645-50. doi: 10.1016/j.prosdent.2020.08.032
• 2. Emam NM. Role of forensic odontology in identification of persons: a review article. Cureus 2024; 16: e56570. doi: 10.7759/cureus.56570
• 3. Colvenkar S, Sv R. Denture marking for forensic identification using laser-marked stainless steel quick response (QR) code. Cureus 2022; 14: e22431. doi: 10.7759/cureus.22431
• 4. Ali MM, Colvenkar S, Omer NS, Mysolla SR, Noureen F. Prosthodontic management with a metal denture engraved with laser QR code. Cureus 2023; 15: e34483. doi: 10.7759/cureus.34483
• 5. Lose FM. Denture identification. J Prosthet Dent 1958; 8: 940-1.
• 6. Altheim IJ. Vital identification data from denture. Dent Dig 1963; 69: 114-5.
• 7. Harvey W. Marking on dentures, letter. Br Dent J 1970; 128: 111-2.
• 8. Matsumura H, Shimoe S, Nagano K, Tanoue N. International telephone code used for citizenship identification in a denture. J Oral Sci 2007; 49: 337-40. doi: 10.2334/josnusd.49.337
• 9. Narang V, Kuckreja H, Oberoi N, Kaur J, Birdi NK, Mahajan S. Resistance of a novel denture identification system to various assault: an in-vitro study. J Indian Prosthodont Soc 2021; 21: 180-5. doi: 10.4103/jips.jips_24_21
• 10. Krishna Teja G, Rao BL, Satyanarayana T, Sravanthi T, Padmini D, Saikumar CD. Digital record for removable denture patients. Case Rep Dent 2023; 2023: 5712978. doi: 10.1155/2023/5712978