A systematic review and meta-analysis in the October 2026 issue of the Journal of Dentistry included 21 laboratory (in vitro) studies on sodium hypochlorite (NaOCl) and 3D-printed denture base resins. At 1%, NaOCl worked against Candida albicans but also increased colour change and surface roughness and reduced hardness, flexural strength and elastic modulus. The authors conclude the evidence is insufficient to establish an optimal concentration, exposure time or frequency, and does not support a specific clinical protocol.
For practices working with 3D-printed denture bases, how to clean and disinfect them is a practical question. As of October 2026, this review is a recent pooled summary of the laboratory evidence on a widely used disinfectant. For practices in Toronto and across the GTA that deliver, reline or adjust printed dentures, its message is narrow but useful: a disinfectant that is active against Candida on a printed resin can also change the resin.
What the Review Studied
The paper, "Sodium hypochlorite for 3D-printed denture base resins disinfection: a systematic review and meta-analysis," is by Nunes GP, Sales LS, Peres GR, Dos Santos PB, Alves RO and Sugio CYC. Europe PMC lists it in the Journal of Dentistry's October 2026 issue, first published online on October 7, 2026.
According to the abstract, the authors set out to assess two things at once: how well NaOCl acts against microbes on 3D-printed denture base resins, and what it does to the material's properties. They followed PRISMA guidelines and searched PubMed/MEDLINE, Scopus, Embase, the Cochrane Library and Web of Science through October 1, 2026. Meta-analyses were run in RevMan, and risk of bias was assessed with the Quality Assessment Tool for In Vitro Studies (QUIN).
- Studies included: 21, all in vitro.
- Concentrations tested: 0.25% to 1% NaOCl.
- Where the numbers come from: the authors note that 1% NaOCl provided most of the quantitative evidence.
- Risk of bias: the QUIN assessment indicated low risk of bias.
What 1% Sodium Hypochlorite Did to Printed Denture Resin
Compared with negative controls, the review reports that 1% NaOCl showed antimicrobial activity against Candida albicans (mean difference −4.53). The same comparison found changes in the resin itself:
- Colour change increased (standardized mean difference 1.51).
- Surface roughness increased (mean difference 0.04 µm).
- Hardness decreased (standardized mean difference −0.88).
- Flexural strength decreased (mean difference −7.56 MPa).
- Elastic modulus decreased (mean difference −371.45 MPa).
The authors also compared 1% NaOCl with commercial disinfectants. They report that it caused greater colour change than Corega and Fittydent and greater roughness than Efferdent, but lower roughness and hardness than Fittydent. Values were similar to Corega for roughness and hardness, to Listerine for colour change and roughness, and to Efferdent for colour change. In other words, NaOCl was not uniformly worse than the branded alternatives tested; the picture depends on which property you look at.
Why the Authors Stopped Short of a Protocol
The most important line in the paper may be its conclusion. The authors state that the evidence is insufficient to establish an optimal concentration, exposure time or frequency. In their clinical-relevance statement they add that although 1% NaOCl significantly affected some material properties, these differences were not uniformly clinically relevant, and that the available evidence does not support a specific protocol for clinical use. They call for further work on lower concentrations to see whether microbial control can be achieved while preserving material properties.
Three limits are worth keeping in view when you read this review:
- Every included study was in vitro. The findings describe resin specimens in a laboratory, not dentures in patients' mouths over months of wear.
- Most of the pooled numbers come from 1% NaOCl. The review does not establish what happens at lower concentrations; it flags that as the open question.
- This summary is based on the published abstract. The abstract does not report resin brands, exposure times or test methods; those would need to be checked in the full paper.
Pro Tip: Before adopting any soaking routine for printed bases, ask the dental laboratory or resin manufacturer for its written cleaning and disinfection instructions, and keep that document in your IPAC binder next to your other manufacturer instructions for use.
What It Means for IPAC in Ontario Practices
The review lands on a point the Royal College of Dental Surgeons of Ontario (RCDSO) already makes in its Standard of Practice, Infection Prevention and Control in the Dental Office (approved November 2018). In its Dental Laboratory Asepsis section, the RCDSO identifies dental prostheses and appliances, along with items used to fabricate them, as potential sources of cross-contamination.
The standard asks the dental office and the commercial dental laboratory to coordinate so that appropriate cleaning and disinfection is performed, so that materials are not damaged or distorted by overexposure to disinfectants, and so that disinfection steps are not unnecessarily duplicated. It also directs that impressions, prostheses and appliances be cleaned and disinfected as soon as possible after removal from the mouth, and that the manufacturer's instructions on the stability of specific materials during disinfection be consulted. Finished prostheses delivered to the patient must be free of contamination, which the standard says can be achieved with an appropriate low-level disinfectant by either the laboratory or the office.
Read together, the RCDSO standard tells you to protect the material as well as disinfect it, and the new review shows why that matters for printed resins specifically. The review offers no validated protocol for printed resins yet, so cleaning habits built around other denture materials should not be assumed to carry over.
Practical Questions to Raise With Your Lab
None of the following is a clinical protocol; the review says the available evidence does not support a specific protocol. These are the conversations the RCDSO's coordination requirement points toward:
- Which resin is this? Ask your laboratory to name the printed denture base material on the lab slip so you can look up its instructions.
- Who disinfects, and with what? Agree in writing whether the lab or the office performs the final disinfection before delivery, so the step is neither skipped nor doubled.
- What does the resin maker allow? Request the manufacturer's guidance on compatible disinfectants and contact times for that material.
- What will you tell the patient? Home-care instructions for printed dentures should come from the same manufacturer guidance, not from habit.
Pro Tip: Add printed denture bases as a separate line in your office IPAC policy manual, listing the disinfectant, contact time and source document for each material your labs use. Review it whenever a lab changes materials, so the entry always matches the resin you are actually receiving.
EBIKO Dental will continue monitoring research on digital prosthodontic materials and infection prevention and control (IPAC), and will report on follow-up studies of lower NaOCl concentrations as they are published. For more news and supply guides for Canadian practices, visit EBIKO Dental.
Sources
- Nunes GP, Sales LS, Peres GR, Dos Santos PB, Alves RO, Sugio CYC. Sodium hypochlorite for 3D-printed denture base resins disinfection: a systematic review and meta-analysis. Journal of Dentistry, October 2026. doi:10.1016/j.jdent.2026.107098
- Royal College of Dental Surgeons of Ontario. Standard of Practice: Infection Prevention and Control in the Dental Office (approved November 2018).
Frequently Asked Questions
Q: Does sodium hypochlorite damage 3D-printed dentures?
In laboratory studies pooled by a 2026 Journal of Dentistry review, 1% sodium hypochlorite increased colour change and surface roughness and reduced hardness, flexural strength and elastic modulus of 3D-printed denture base resins. The authors note these differences were not uniformly clinically relevant, and all 21 included studies were in vitro.
Q: What concentration of bleach should be used to disinfect a printed denture?
The review's authors state that current evidence is insufficient to set an optimal concentration, exposure time or frequency, and that it does not support a specific clinical protocol. Consult the resin manufacturer's instructions on material stability and coordinate with your dental laboratory, as the RCDSO's IPAC standard advises.
Q: What does the RCDSO require for disinfecting dentures in Ontario?
The RCDSO's Infection Prevention and Control standard requires prostheses to be cleaned and disinfected as soon as possible after removal from the mouth and delivered to the patient free of contamination, and says the manufacturer's instructions on material stability should be consulted. It also asks offices and labs to coordinate so materials are not damaged by overexposure to disinfectants.