A comparison of decontamination methods of tried-in preformed metal crowns: an in-vivo study

Comparative Evaluation of Preformed Stainless Steel Crown's Crazing at Different Autoclave Cycles

Aim

The study aimed to assess and compare the crazing of preformed stainless steel (SS) crowns at various autoclave cycles.

Materials and methods

Around 15 SS crowns were subjected to zero (unsterilized), one, three, five, and seven autoclave cycles at 121°C, 15 psi for 20 minutes. After each autoclave cycle, the mesial surface of each crown from occlusal to cervical portions was examined under a 40× stereomicroscope. Crazing was evaluated using Wickersham's criteria.

Results

One autoclave cycle does not produce any cracks, whereas the higher the number of autoclave cycles, the higher the cracks, which affects the prognosis of the SS crown treatment.

Conclusion

Surface alterations of SS crowns after different autoclave cycles were significant. So, preformed SS crowns should be discarded after sterilizing once or twice during clinical practice.

How to cite this article

Sowkarthicaa P, Mathian VM, Gawthaman M, et al. Comparative Evaluation of Preformed Stainless Steel Crown's Crazing at Different Autoclave Cycles. Int J Clin Pediatr Dent 2023;16(S-1):S77-S80.

Disinfection of polyvinyl siloxane impression material using ozone gas, 0.1% riboflavin, glutaraldehyde, and microwave irradiation and their effect on physical properties

AIM

To assess the antimicrobial effect of ozone gas (OG) 0.1% riboflavin (RF), glutaraldehyde (GaH), and microwave irradiation (MI) on Polyvinyl siloxane impression material formerly colonized with E. coli, P. Aeruginosa, E. faecalis, and S.aureus and their effect on the physical properties MATERIAL AND METHODS: One hundred disk-shaped specimens (diameter 10 mm and thickness 3 mm) were developed by using polyvinylsiloxane impression material and inoculated by the American Type Culture Collection (ATCC) of E. coli, P. aeruginosa, E. faecalis, and S.aureus in an in-vitro setup. The samples were arbitrarily isolated into five groups and subjected for 3 min to the designated disinfection modality. Group 1 Control, group 2: GaH, group 3: 0.1% RF, group 4: MI, and group 5 OG. Following decontamination, the physical properties (contact angle, strain-in-compression, and tear strength) of impression materials were evaluated. Statistical analysis for CFU/mL (log10) for exposed E. coli, P. aeruginosa, E. faecalis, and S.aureus was performed by using analysis of variance (ANOVA) and Tukey's multiple comparison tests at a p-value of less than 0.05.

RESULTS

The most effective antimicrobial efficacy for impression disinfection against all scrutinized microbial colonies were displayed by group 5 OG and the lowest disinfection effectiveness was unveiled by the control group with no treatment. The intragroup comparison revealed that impression disinfection with GaH, MI, and ozone corroborated analogous antimicrobial efficacy(p > 0.05). The disinfecting capacity of the impression material with 0.1% RF was significantly less than MI, GaH, and OG (p < 0.05).

CONCLUSION

Disinfection of polyvinyl siloxane impression material with ozone gas, microwave irradiation, and glutaraldehyde demonstrated reasonable antimicrobial efficiencies against E. coli, P. aeruginosa, E. faecalis, and S.aureus with no detrimental effects on the physical properties of impression material. More studies are advocated to extrapolate the findings of the present study.

Decontamination practices of paediatric crowns: a systematic review

Purpose

A systematic review was conducted into paediatric crown decontamination practices using the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines.

Method

After database retrieval using predefined search terms, two reviewers independently applied the selection criteria, extracted the data, and assessed for risk of bias. From 92 potentially eligible studies, 10 were included for analysis.

Results

Steam sterilisation (autoclaving) was used as the gold standard for reducing biological contaminants on paediatric crowns across in vivo studies. However, autoclaving was associated with microstructural changes such as crazing and contour alterations. Furthermore, several tooth coloured crowns were liable to undergo colour changes from steam sterilisation.

Conclusion

Ambiguous manufacturer guidelines on protocols for reprocessing and reuse after biological exposure raises concerns regarding cross contamination and leaves practitioners open to potential litigation. A better understanding of the compatibility of paediatric crowns and decontamination practices is needed. More research into alternative chairside technologies that use low temperature, such as hydrogen peroxide gas plasma sterilisation, is warranted.

Effects of decontamination protocols on the aesthetic, morphological, and material composition of preformed paediatric crowns

BACKGROUND

Preformed crowns (PCs) are exposed to potentially infectious bodily fluids during the trial fit; however, whether they can be safely re-used remains uncertain. This study determined the effects of decontamination methods on various PCs. The key criteria examined were aesthetic, morphological, and elemental characteristics.

DESIGN

This is a laboratory-based experimental study. Stainless steel, pre-veneered stainless steel, and zirconia PCs underwent either: (a) ultrasonic cleaning with EmPower^® followed by steam sterilisation, (b) thermal disinfection in an instrument washer with Asepti^® Neutraliser/Asepti^® followed by steam sterilisation, or (c) immersion in an ortho-phthalaldehyde (OPA) instrument-level disinfectant. The methods were performed for 1, 5, or 10 cycles, and scanning electron microscopy (SEM); red, green, and blue (RGB) value; and luminosity value were tracked (using a histogram of individual colour reference chips in Adobe Photoshop^® ) to assess colour changes, and energy-dispersive X-ray (EDX) spectroscopy to characterise the material composition.

RESULTS

Pre-veneered stainless steel crowns showed isolated zones of darkening with loss of luminosity and variations in green and blue values after ultrasonic or thermal washer disinfection combined with steam autoclaving at 5 and 10 cycles. No changes occurred with OPA. Both SEM imaging and EDX analysis identified no changes to crown materials from any of the three reprocessing methods.

CONCLUSIONS

Reprocessing protocols need to reflect the differing responses of various types of PCs. Repeated steam sterilisation causes slight aesthetic alterations by way of colour instability and loss of luminosity to pre-veneered stainless steel crowns, but no issues with stainless steel or zirconia PCs.

Efficacy of contemporary agents on disinfection and surface roughness of polyetheretherketone implant abutments

AIM

The present study was designed to estimate the disinfection and surface roughness (Ra) of colonized (E. coli, C. albicans, S.aureus, and S. mutans) PEEK implant abutment disinfected with PDT, chemical, and herbal agents.

MATERIAL AND METHODS

The American Type Culture Collection (ATCC) inoculated E.coli, C.albicans, S.mutans, and S.aureus in an in-vitro scenario using 60 PEEK implant abutment samples provided by the manufacturer. Following that, the samples were distributed in four disinfection methods categories - group 1: 5mM Rose Bengal PS (RB), group 2: ultrasonic disinfection (UD), group 3: 2% glutaraldehyde (GaH), and group 4: tea tree oil (TTO). To scrutinize the data and compare the means and standard deviations of CFU/mL (log10) for exposed E. coli, Candida albicans, S.aureus, and S.mutans, a two-way ANOVA and Tukey's multiple comparison test were performed.

RESULTS

Specimens treated with 2% GaH, UD, and TTO validated a significant reduction in E. coli, C. albicans, S aureus, and S. mutans CFU/mL (log10) colonies. Intragroup assessment designated that there is no reduction in CFU/mL (log10) of E.coli and C.albicans when PEEK implant abutment specimens are irradiated with 5Mm RB. A decline is seen in values of S. aureus, and S. mutans microbial strains on treatment with all four cleansers while the computation of C.albicans and E.coli colonies unveiled significant reduction with GaH, UD, and TTO except RB (p<0.05). The results of Ra showed that PEEK fabricated implant abutment specimens, when treated with UD (3.472±0.561μm), displayed a significantly higher Ra value as compared to other analyzed cleansing methods.

CONCLUSION

. Disinfection with 2% glutaraldehyde and Tea tree oil showed maximum antimicrobial efficacy and lower Ra values for PEEK implant abutments colonized with bacterial strains of E.coli, C.albicans, S.aureus, and S.mutans.

Efficacy of 75% alcohol in pretreatment of the Andersen sampler in trapping maximum airborne microbes

The present study was conducted to evaluate the effects of the pretreatment methods and sampling time on the sampling of airborne bacteria in hospitals. Methods for the pretreatment of Andersen samplers, namely, non-sterilized, 75% ethanol and autoclaving sampled for 5 min, 10 min and 15 min in the general ward and class 1000 clean operating department, respectively, were studied. Statistical analysis was used to compare the differences in sampling results of airborne bacteria under different pretreatment methods, sampling time and environmental conditions. In the first test, the sampling results of the airborne bacteria obtained by pretreatment of the sampler with 75% ethanol and without pre-treatment were not very different, and the sampling results showed a certain declining trend with the extension of the sampling time. In the second test, the pretreatment effect of autoclaving was significantly better than that of 75% ethanol, and the sampling time had no effect on the sampling results. After removing the influencing factors of the environment, the results were consistent with the results of the second test. It was observed that the Andersen samplers should not be pretreated with 75% ethanol before airborne microbes sampling. The pretreatment should be carried out by autoclaving, and the sampling time has little effect on the sampling results.