Evaluation of Candida albicans biofilm formation on conventional and computer-aided-design/computer-aided manufacturing (CAD/CAM) denture base materials

Biofilm Formation on Denture Base Material Reinforced With a Novel Organic Material

BACKGROUND

Microcrystalline cellulose (MCC) is a novel organic material developed by one of the authors in this study. When MCC was incorporated with conventionally available denture base resin, it demonstrated increased flexural strength and flexural modulus. However, it was speculated that because the material is organic, it can promote the growth of Candida. The purpose of this study is to evaluate the Candida albicans biofilm formation on polymethyl methacrylate (PMMA) denture base resin incorporated with MCC.

MATERIALS AND METHODS

MCC is an organic material extracted from the oil palm empty fruit bunch (OPEFB). The growth of C. albicans and biofilm formation in three test groups were compared by biofilm assay and imaging techniques like microscopy (by safranin staining) and scanning electron microscopy. The three test groups were comprised of MCC-reinforced PMMA containing OPEFB fibers of 50-micrometer thickness at 5% weight reinforcement, conventionally and commercially available heat cure PMMA, and an empty well to assess any discrepancies from the environment.

RESULTS

The test groups showed increased biofilm formation by C. albicans compared to commercially and conventionally available heat cure PMMA. Reinforcement with MCC showed higher biofilm formation of 1.43 times higher compared to conventional PMMA. Biofilms formed by Candida albicans on MCC-reinforced PMMA appeared heterogeneous in structure, comprised of yeast cells and hyphae, surrounded by a higher density of polysaccharide extracellular matrix material compared to that of conventionally available heat cure PMMA.

CONCLUSION

Biofilm formation is increased in denture base resin incorporated with MCC. More investigation is warranted to study the antifungal efficacy of the addition of antifungal agents to the reinforced denture base resin.

Efficacy of denture cleansers on Candida albicans adhesion and their effects on the properties of conventional, milled CAD/CAM, and 3D-printed denture bases

OBJECTIVES

Evaluate the efficacy of denture cleaners on the adhesion of Candida albicans and their effects on the surface, optical, and mechanical properties of resins for conventional, milled, and 3D-printed denture bases.

MATERIALS AND METHODS

A total of 240 resin samples were made, 120 for testing Candida albicans adhesion, optical stabilities (ΔE00), roughness (Ra), hydrophilicity (°), surface free energy (Owens-Wendt) and 120 samples for testing Candida albicans adhesion, surface microhardness (Knoop), flexural strength and modulus of elasticity in a three-point test, in which they were divided into 3 groups of denture resin (n = 40) and subdivided into 5 cleaners of dentures (n = 8). Data were evaluated by two-way ANOVA and Tukey's test for multiple comparisons (α = 0.05).

RESULTS

Denture cleaners with an alkaline solution and dilute acid composition were those that showed the greatest effectiveness in reducing Candida albicans (P < 0.001), however 1% NaOCl significantly affected the properties of the resins (P < 0.05). Denture 3D-printed showed that the surface microhardness was significantly lower for all cleansers (P < 0.05).

CONCLUSIONS

Listerine demonstrated superior efficacy in reducing Candida albicans with minimal effect on denture properties, whereas 1% NaOCl had a significant negative impact on the properties. The mechanical properties were significantly lower in 3D-printed resin than in other resins for all denture cleansers.

CLINICAL RELEVANCE

Denture base materials are being sold to adapt to the CAD/CAM system, increasing the number of users of dentures manufactured with this system. Despite this, there is little investigation into denture cleaners regarding the adhesion capacity of microorganisms and the optical, surface and mechanical properties of dentures, thus requiring further investigation.

The accuracy and retention of presurgical infant orthopaedics constructed from different polymer materials: A comparative study

Objectives

This laboratory-based study aimed to evaluate and compare the accuracy and retention of moulding plates when used as pre-surgical orthopaedic appliances (PSIOs) for infants with cleft lip and/or palate (CL/P).

Methods

Ten moulding plates were fabricated from three different materials (total sample size: 30), including polymethyl methacrylate (PMMA), a hard clear aligner (PET-G polymer), and a dual-layered hard and soft clear aligner (mixed PET-G/EVA) on ten three-dimensional (3D) printed working models. Accuracy was evaluated by measuring the virtual gap between the data acquired from the moulding plate and the working model after the optical scanning at each of the designated 36 points for each plate. Exocad software was used to facilitate all virtual alignments and measurements. Retention was measured using a digital gauge that quantified the traction force required to separate the plates from the retention test cast (a soft resin printed cast).

Results

PET-G plates exhibited the best fit with the working cast, with overall adaptations of 0.146 ± 0.012 for PET-G, 0.250 ± 0.073 for PET-G/EVA, and 0.294 ± 0.113 for PMMA. For region-specific misfit, PET-G plates exhibited superior accuracy across all regions, with mean discrepancies of 0.16 ± 0.08 mm, 0.15 ± 0.061 mm, and 0.12 ± 0.128 mm in the anterior, middle, and posterior regions, respectively. Retention for PET-G was significantly higher than the other materials, with a mean of 3.34 N ± 0.487, as opposed to 1.65 N ± 0.331for PMMA and 1.27 N ± 0.239 for PET-G/EVA (P < 0.05).

Conclusions

Moulding plates constructed from PET-G exhibited a better fit and higher retention than those made from PET-G/EVA and PMMA.

Clinical significance

Collectively, our findings suggest that the selection of PET-G for PSIO appliances could have clinical significance by potentially improving treatment outcomes in infants with CL/P.

Assessing the effect of Artemisia sieberi extracts on surface roughness and candida growth of digitally processed denture acrylic materials

BACKGROUND

Denture stomatitis, frequently encountered, is generally addressed symptomatically, with limited exploration of preventive approaches involving antifungal medicinal plants.

OBJECTIVE

This study assessed the impact of Artemisia sieberi extracts on the candida growth of conventional and digitally processed acrylic materials.

METHOD

Thirty acrylic resin discs (3 mm thickness × 10 mm diameter) were prepared by conventional or CAD/CAM technology (milling and 3D printing). The resin discs were exposed to simulated brushing, thermocycling, and immersion in Artemisia sieberi extract for 8 hours. The surface roughness of the discs was assessed at baseline and after immersion in Artemisia sieberi extract. Candida growth was quantified through colony-forming units (CFU/mL). Data was analyzed using SPSS v.22 (α⩽ 0.05).

RESULTS

Irrespective of the material type, the post-immersion surface roughness was significantly higher compared to pre-immersion values (p< 0.05). Candida growth was significantly higher in conventional acrylic materials than digitally fabricated acrylics (p< 0.05). At × 3, Ra and CFU were found to be moderately positive and non-significantly correlated (R= 0.664, p= 0.149). At × 4, Ra and CFU were found to be weak positive and non-significantly correlated (R= 0.344, p= 0.503).

CONCLUSION

Artemisia sieberi extracts had a notable impact on digitally fabricated denture acrylics, reducing candida albicans growth compared to conventional heat-cured acrylic. This suggests a potential role for these extracts in improving denture hygiene and preventing denture stomatitis, particularly in the context of digitally fabricated dentures.