Effectiveness of experimental dentifrices based on essential oils on biofilm on complete dentures: an in vitro study

Abstract Specific products containing natural resources can contribute to the innovation of complete denture hygiene. Objective: To conduct an in vitro evaluation of experimental dentifrices containing essential oils of Bowdichia virgilioides Kunth (BvK), Copaifera officinalis (Co), Eucalyptus citriodora (Ec), Melaleuca alternifolia (Ma) and Pinus strobus (Ps) at 1%. Methodology: The variables evaluated were organoleptic and physicochemical characteristics, abrasiveness (mechanical brushing machine) simulating 2.5 years, and microbial load (Colony Forming Units - CFU/mL), metabolic activity (XTT assay) and cell viability (Live/Dead® BacLight™ kit) of the multispecies biofilm (Streptococcus mutans: Sm, Staphylococcus aureus: Sa, Candida albicans: Ca and Candida glabrata: Cg). Specimens of heat-polymerized acrylic resins (n=256) (n=96 specimens for abrasiveness, n=72 for microbial load count, n=72 for biofilm metabolic activity, n=16 for cell viability and total biofilm quantification) with formed biofilm were divided into eight groups for manual brushing (20 seconds) with a dental brush and distilled water (NC: negative control), Trihydral (PC: positive control), placebo (Pl), BvK, Co, Ec, Ma or Ps. After brushing, the specimens were washed with PBS and immersed in Letheen Broth medium, and the suspension was sown in solid specific medium. The organoleptic characteristics were presented by descriptive analysis. The values of density, pH, consistency and viscosity were presented in a table. The data were analyzed with the Wald test in a generalized linear model, followed by the Kruskal-Wallis test, Dunn's test (mass change) and the Bonferroni test (UFC and XTT). The Wald test in Generalized Estimating Equations and the Bonferroni test were used to analyze cell viability. Results: All dentifrices showed stable organoleptic characteristics and adequate physicochemical properties. CN, Ec, Ps, Pl and PC showed low abrasiveness. There was a significant difference between the groups (p<0.001) for microbial load, metabolic activity and biofilm viability. Conclusions: It was concluded that the BvK, Ec and Ps dentifrices are useful for cleaning complete dentures, as they have antimicrobial activity against biofilm. The dentifrices containing Bowdichia virgilioides Kunth showed medium abrasiveness and should be used with caution.

Physical properties and color stability of injection-molded thermoplastic denture base resins

PURPOSE: The purpose of this study was to compare mechanical and physical properties of injection-molded thermoplastic denture base resins. MATERIALS AND METHODS: In this study, six commercially available products (VA; Valplast, LC; Lucitone, ST; Smiltone, ES; Estheshot-Bright, AC; Acrytone, WE; Weldenz) were selected from four types of thermoplastic denture base materials (Polyamide, Polyester, Acrylic resin and Polypropylene). The flexural properties and shore D hardness have been investigated and water sorption and solubility, and color stability have evaluated. RESULTS: For the flexural modulus value, ES showed the highest value and WE showed significantly lower value than all other groups (P < .05). Most of experimental groups showed weak color stability beyond the clinically acceptable range. CONCLUSION: Within the limits of this study, thermoplastic denture base resin did not show sufficient modulus to function as a denture base. In addition, all resins showed discoloration with clinical significance, and especially polyamides showed the lowest color stability.

The staining effect of coffee and red tea to two kinds of denture base materials and the cleaning efficacy of four kinds of denture cleansers to the stains / 口腔疾病防治

Objective@#To compare the staining effect of coffee and red tea to the different denture base materials, and to investigate the cleaning efficacy of four denture cleansers.@*Methods @#All samples were separately soaked in 1％NaClO、 Efferdent、 Polident partial and Polident overnight for 12 times within 12 days after staining by the coffee and red tea. Then, the color values of the samples were measured by the spectrocolorimeter. @*Results @#The staining effect between coffee and red tea in the two materials was statistically significant (P < 0.05); the invisible denture materials are easily colored than heat-curing denture base resins (P < 0.05); there was also a statistical difference in the cleaning effect of the denture cleaning agents at each cycle stage (P < 0.05); the trend is different in different phases of color difference (ΔE) (P < 0.05). @*Conlusion@#Compared with the Polident partial, the cleaning efficacy of 1％NaClO、Efferdent and Polident overnight were better.

The staining effect of coffee and red tea to two kinds of denture base materials and the cleaning efficacy of four kinds of denture cleansers to the stains / 口腔疾病防治

Objective@#To compare the staining effect of coffee and red tea to the different denture base materials, and to investigate the cleaning efficacy of four denture cleansers.@*Methods@#All samples were separately soaked in 1％NaClO、 Efferdent、 Polident partial and Polident overnight for 12 times within 12 days after staining by the coffee and red tea. Then, the color values of the samples were measured by the spectrocolorimeter.@*Results @#The staining effect between coffee and red tea in the two materials was statistically significant (P < 0.05); the invisible denture materials are easily colored than heat-curing denture base resins (P < 0.05); there was also a statistical difference in the cleaning effect of the denture cleaning agents at each cycle stage (P < 0.05); the trend is different in different phases of color difference (ΔE) (P < 0.05).@*Conlusion@#Compared with the Polident partial, the cleaning efficacy of 1％NaClO、Efferdent and Polident overnight were better.

Investigation of the cytotoxicity of thermoplastic denture base resins

PURPOSE: The purpose of this study was to investigate the in vitro cytotoxicity of thermoplastic denture base resins and to identify the possible adverse effects of these resins on oral keratinocytes in response to hot water/food intake. MATERIALS AND METHODS: Six dental thermoplastic resin materials were evaluated: three polyamide materials (Smile tone, ST; Valplast, VP; and Luciton FRS, LF), two acrylic materials (Acrytone, AT; and Acryshot, AS), and one polypropylene resin material (Unigum, UG). One heat-polymerized acrylic resin (Vertex RS, RS) was chosen for comparison. After obtaining extracts from specimens of the denture resin materials (Φ=10 mm and d=2 mm) under different extraction conditions (37℃ for 24 hours, 70℃ for 24 hours, and 121℃ for 1 hour), the extracts (50%) or serial dilutions (25%, 12.5%, and 6.25%) in distilled water were co-cultured for 24 hours with immortalized human oral keratinocytes (IHOKs) or mouse fibroblasts (L929s) for the cytotoxicity assay described in ISO 10993. RESULTS: Greater than 70% viability was detected under all test conditions. Significantly lower IHOK and L929 viability was detected in the 50% extract from the VP (70℃) and AT (121℃) samples (P < .05), but only L929 showed reduced viability in the 50% and 25% extract from LF (37℃) (P < .05). CONCLUSION: Extracts obtained from six materials under different extraction conditions (37℃, 70℃, and 121℃) did not exhibit severe cytotoxicity (less than 70% viability), although their potential risk to oral mucosa at high temperatures should not be ignored.

Comparative study of Dimensional Accuracy of Three Conventional Denture Base Resins Processed By Conventional Method And Microwave Polmerization.

Statement of Problem: Poor adaptations of acrylic resin denture bases to the supporting tissues markedly decrease denture retention. Several denture base resin and processing techniques have been introduced to the profession, each claiming to produce a more accurate base. Microwave processing techniques has been introduced claims to minimize the dimensional changes. Purpose: The purpose of this study was to compare the dimensional accuracy of three denture base resins processed by conventional water bath method and by use of microwave energy. Material and method: Three Poly (MethylMethacrylate) heat cure resins were selected for this study.These resins were processed by (i) conventional water bath technique for 1.5 hours at 1650F and half hour at 2120F and (ii) microwave energy for 3 mins at 500W. A metal master die representing a maxillary arch with 4mm hole was prepared to evaluate the adaptation of the test resin denture base. A total number of 60 specimens were tested. The measurements of acrylic resin denture base specimens were compared with the measurements of master metal die dimension keeping it as a standard measurement. Results: The resin record bases processed by microwave curing method had slightly better dimensional accuracy than conventionally processed bases. There was no significant difference found in the dimensional accuracy when Resin record bases processed with a specially formulated resin for microwave curing was microwave cured and when conventionally available resins were processed by microwave technique. Conclusion: The resin record bases processed by microwave curing method had slightly better dimensional accuracy than the conventionally processed bases.

Adherence of Candida albicans to two Denture Base Resins with Different Surface / 中华医院感染学杂志

OBJECTIVE To assess the adherence ability of Candida albicans to two denture base resins with different surface roughness.METHODS In adhesion assays,two denture base resins were made into standard test samples with different surface roughness.Suspension of C.albicans(ATCC 10261) strain was used to adhere on the test samples,and cultured to observe the adhesive effect of a mixed salivary pellicle with Candida to these surfaces.RESULTS In glass surface group,the amount of C.albicans adhering to heat-curing denture base resins was 15.33?2.80,and the amount of C.albicans adhering to Valplast flexible denture resin was 13.67?2.94;In gypsum surface group,the amount of C.albicans adhering to heat-curing denture base resins was 22.67?4.84,and the amount of C.albicans adhering to Valplast flexible denture resin was 21.17?3.31.Significantly greater adhesion of C.albicans to rough surfaces rather than smooth surfaces of the same material was found,at the same time C.albicans had different adhesive ability on different denture base resins(P