Analysis of the residual monomer content in milled and 3D-printed removable CAD-CAM complete dentures: an in vitro study

Murali Srinivasan; Edward Chaoho Chien; Nicole Kalberer; Adrian Miguel Alambiaga Caravaca; Alicia López Castelleno; Porawit Kamnoedboon; Salvatore Sauro; Mutlu Özcan; Frauke Müller; Daniel Wismeijer

doi:10.1016/j.jdent.2022.104094

Analysis of the residual monomer content in milled and 3D-printed removable CAD-CAM complete dentures: an in vitro study

J Dent. 2022 May:120:104094. doi: 10.1016/j.jdent.2022.104094. Epub 2022 Mar 15.

Affiliations

¹ Clinic of General, Special care and Geriatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland; Division of Gerodontology and Removable Prosthodontics, University Clinics of Dental Medicine, University of Geneva, Geneva, Switzerland. Electronic address: murali.srinivasan@zzm.uzh.ch.
² Department of Restorative and Reconstructive Oral Care, Academic Center for Dentistry (ACTA), Amsterdam, the Netherlands.
³ Clinic of General, Special care and Geriatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
⁴ Cardenal Herrera-CEU University, CEU Universities, C/Santiago Ramón y Cajal, s/n., Alfara del Patriarca, 46115, Valencia, Spain.
⁵ Cardenal Herrera-CEU University, CEU Universities, C/Santiago Ramón y Cajal, s/n., Alfara del Patriarca, 46115, Valencia, Spain. Electronic address: salvatore.sauro@uchceu.es.
⁶ Division of Dental Biomaterials, Clinic of Reconstructive Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
⁷ Division of Gerodontology and Removable Prosthodontics, University Clinics of Dental Medicine, University of Geneva, Geneva, Switzerland.
⁸ TPE, Private Practice, Ellecom, the Netherlands.

PMID: 35301079
DOI: 10.1016/j.jdent.2022.104094

Abstract

Objective: The study aimed to quantitatively evaluate the elution of methylmethacrylate from CAD-CAM manufactured removable complete dentures (RCDs) using high performance liquid chromatography (HPLC).

Methods: Thirty-two RCDs were manufactured following either the CNC-milling (Milled: n=8) or the 3D-printing (n=24) protocols. The 3D-printed dentures were further categorized into three groups based on their post-production rinsing cycles [Extended wash cycle (EWC), Standard wash cycle (SWC), and SWC with an additional Durécon coating (SWC2)]. HPLC was used to evaluate the methylmethacrylate concentrations (MMCs) eluted from the dentures in each group for different time periods (1, 2, 4, 8, and 24 hours). Mean and standard deviations were calculated for the MMCs; data was verified for normal distribution, ANOVA and post hoc tests were applied for statistical analyses (⍺=0.05).

Results: The HPLC revealed that all the denture groups recorded some amounts of MMCs, with significant differences [F (3, 31) = 23.646, p<0.0001]. The milled denture group had the highest MMCs at 24 hours when compared to the EWC (p<0.0001), SWC (p=0.001), and SWC2 (p<0.0001) denture groups. SWC had a higher MMC than EWC (p=0.032) and SWC2 (p=0.015). No differences were found in MMCs when comparing EWC and SWC2 (p=0.989).

Conclusion: Methylmethacrylate concentrations were significantly lower in 3D-printed RCDs than in milled RCDs when using the resins employed in this study. Furthermore, the MMCs can be further decreased in 3D-printed RCDs when coated with an additional thin protective layer (Durécon) by following the manufacturer-recommended rinsing protocol or when an extended isopropanol wash cycle is adopted.

Keywords: 3D-printing; CAD-CAM; CAD-CAM milling; Geriatric dentistry; Removable complete dentures; Residual monomer content.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Computer-Aided Design*
Denture, Complete*
Denture, Partial
Methylmethacrylate
Printing, Three-Dimensional

Substances

Methylmethacrylate