Effectiveness of Alcohol and Aldehyde Spray Disinfectants on Dental Impressions

Comparative Evaluation of Disinfection Protocols for Dental Impressions in Prosthodontics

BACKGROUND

In prosthodontics, dental impressions are essential for creating precise dental restorations. However, these impressions are susceptible to microbial contamination, which can pose a risk of infection to patients. Consequently, effective disinfection methods are crucial to prevent postoperative infections. This study aims to evaluate the effectiveness of various disinfection techniques for dental impressions used in prosthodontics.

MATERIALS AND METHODS

A total of 148 poured dental impressions were randomized into three disinfection groups: immersed in 0.5% sodium hypochlorite, 2% glutaraldehyde, or 0.2% chlorhexidine solution. The bacterial contamination was evaluated by direct colony-forming unit (CFU) counting, while the dimensional accuracy and surface detail duplication of each resin sample were determined as physical properties. Data were analyzed using SPSS version 23.0 (IBM Corp., Armonk, NY). Either analysis of variance (ANOVA) with the option for post-hoc or non-parametric tests was used to investigate and compare the efficacy of the better disinfection protocols where the p-value was considered significant if less than 0.05.

RESULTS

Glutaraldehyde showed the lowest mean CFU count (2.5 log10 CFUs), followed by sodium hypochlorite (3.2 log10 CFUs) and chlorhexidine (3.5 log10 CFUs). All disinfection protocols were able to significantly reduce microbial contamination when compared with the control group (p < 0.05). The results of the physical property assessment demonstrated acceptable dimensional accuracy in all tested protocols, with slight differences recorded between them regarding the reproduction of surface detail. More specifically, the mean dimensional deviation was in the range between 0.02 and 0.04 mm, while scores for surface detail reproduction ranged from 2 to 4. The ANOVA results revealed significant differences in microbial contamination levels (F(2, 145) = 5.72, p = 0.007) and dimensional accuracy (F(2, 145) = 3.45, p = 0.032) between the various disinfection protocols.

CONCLUSION

This study enlightens the effective sterilization protocol to be adopted in prosthodontics for dental impressions. Glutaraldehyde was most effective in microbial reduction, while sodium hypochlorite and chlorhexidine were equally effective. Therefore, clinicians must be vigilant in assessing the type of microbial flora that can be encountered during prosthodontic procedures while choosing disinfection protocols for patient safety and quality of impressions.

Efficacy and design requirements of UV light cabinets for disinfection of exchangeable non-sterilizable "dental objects"

Non-sterilizable items such as prosthodontics items constitute a high risk of transmitting dangerous pathogens, including Coronavirus, between patients and healthcare personnel. Although UV rays are recognized for their germicidal efficacy, large and expensive UV devices previously hindered their adoption in dental offices. During the COVID-19 pandemic, small UV devices became available for domestic use, albeit with varying designs and effectiveness. Our study assesses the disinfection capacity of a UV light cabinet for four dental materials and discusses crucial design features for effective performance. Specimens of each material (silicone impressions, stone cast, acrylic denture base, and indelible pencils) were contaminated with Escherichia coli Bl21, and randomly divided into three study groups: UV device (UVG), impressions disinfection solution (SG), and control (CG). The experiment was repeated thrice, and disinfection efficacy assessed by colony forming units (CFU) count. A 2.5-min UV exposure achieved full disinfection for all materials. Significantly different results were found between groups (p < 0.05, one-way ANOVA, Tukey HSD), except for indelible pencils, where UVG and SG were both highly effective. UV cabinets surpass SG's disinfection efficacy. Compact UV devices can offer affordable, portable, and efficient disinfection for non-sterilizable dental objects, with careful consideration of wavelength, exposure, intensity, and safety.

Mechanical and Physical Properties of an Experimental Chemically and Green-Nano Improved Dental Alginate after Proven Antimicrobial Potentials

OBJECTIVES

Impression materials could be a source of cross-contamination due to the presence of microorganisms from blood and saliva inside the oral cavity. Nevertheless, routinely performed post-setting disinfection could compromise the dimensional accuracy and other mechanical properties of alginates. Thus, this study aimed to evaluate detail reproduction, dimensional accuracy, tear strength, and elastic recovery of new experimentally prepared self-disinfecting dental alginates.

METHODS

Two antimicrobial-modified dental alginate groups were prepared by mixing alginate powder with 0.2% silver nitrate (AgNO3 group) and a 0.2% chlorohexidine solution (CHX group) instead of pure water. Moreover, a third modified group was examined by the extraction of Boswellia sacra (BS) oleoresin using water. The extract was used to reduce silver nitrate to form silver nanoparticles (AgNPs), and the mixture was used as well in dental alginate preparation (BS + AgNP group). Dimensional accuracy and detail reproduction were examined as per the ISO 1563 standard guidelines. Specimens were prepared using a metallic mold engraved with three parallel vertical lines 20, 50, and 75 µm wide. Detail reproduction was evaluated by checking the reproducibility of the 50 µm line using a light microscope. Dimensional accuracy was assessed by measuring the change in length between defined reference points. Elastic recovery was measured according to ISO 1563:1990, in which specimens were gradually loaded and then the load was released to allow for recovery from the deformation. Tear strength was evaluated using a material testing machine until failure at a crosshead speed of 500 mm/min.

RESULTS

The recorded dimensional changes between all tested groups were insignificantly different and within the reported acceptable values (between 0.037-0.067 mm). For tear strength, there were statistically significant differences between all tested groups. Groups modified with CHX (1.17 ± 0.26 N/mm) and BS + AgNPs (1.11 ± 0.24 N/mm) showed higher tear strength values compared to the control (0.86 ± 0.23 N/mm) but were insignificant from AgNO3 (0.94 ± 0.17 N/mm). All tested groups showed elastic recovery values that met both the ISO standard and ADA specifications for elastic impression materials and tear strength values within the acceptable documented ranges.

DISCUSSION

The CHX, silver nitrate, and green-synthesized silver nanoparticles could be promising, inexpensive alternatives for the preparation of a self-disinfecting alginate impression material without affecting its performance. Green synthesis of metal nanoparticles could be a very safe, efficient, and nontoxic method, with the advantage of having a synergistic effect between metal ions and active chemical constituents of plant extracts.

A Review on Risk Management of Coronavirus Disease 19 (COVID-19) Infection in Dental Practice: Focus on Prosthodontics and All-Ceramic Materials

Background: A novel β-coronavirus infection (COVID-19) was first detected in Wuhan city, spreading rapidly to other countries and leading to a pandemic. Dental professionals and patients are exposed to a high risk of COVID-19 infection, particularly in the prosthodontic practice, because of the bio-aerosol produced during teeth preparation with dental handpieces and the strict contact with oral fluids during impression making. This paper aimed to provide an overview to limit the risk of transmission of COVID-19 infections during prosthetic procedures in dental offices. Methods: An electronic search was conducted on the electronic databases of PubMed/Medline, Google Scholar, Embase, Scopus, Dynamed, and Open Grey with the following queries: (COVID-19) AND/OR (SARS-CoV-2) AND/OR (Coronavirus) AND/OR (contaminated surface) AND/OR (cross-infection) AND/OR (Prosthodontics) AND/OR (dental ceramic) AND/OR (glass-ceramic). A manual search was performed as well. Results: From the 1023 collected records, 32 papers were included. Conclusions: Dental offices are at high risk of spreading SARS-CoV-2 infection due to the close contact with patients and continuous exposure to saliva during dental procedures. Therefore, pre-check triages via telephone, decontamination, the disinfection of impressions, the sterilization of scanner tips, and the use of specific personal protective equipment, dental high-speed handpieces with dedicated anti-retraction valves, and effective mouthwashes are strongly recommended.

Evaluation of Antimicrobial Efficacy of UVC Radiation, Gaseous Ozone, and Liquid Chemicals Used for Disinfection of Silicone Dental Impression Materials

Effective disinfection of dental impressions is an indispensable requirement for the safety of dental personnel and patients. The ideal method should be not only effective but also convenient, cheap, and environmentally friendly. This study aimed to reliably evaluate the efficacy of ultraviolet C (UVC) radiation, gaseous ozone, and commercial liquid chemicals used for silicone dental impressions disinfection. These methods were applied to two types of elastomeric impression materials: condensation silicones and addition silicones of various consistency (putty, medium, and light). The antimicrobial effectiveness against Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans was evaluated in vitro by counting colony-forming units (CFU) on the surface of samples. The one-way ANOVA with a Tukey HSD test or the Kruskal–Wallis with a Dunn’s test was performed. The results obtained revealed the efficacy of the proposed methods for disinfection of both C-silicones and A-silicones in most of the studied groups. Only one material (Panasil initial contact Light) was not effectively disinfected after UVC irradiation or ozone application. In conclusion, the potential of each disinfection method should be evaluated separately for each material. Moreover, in further research, the possible influence of the proposed methods on the physical properties of the impression materials should be thoroughly investigated.

COVID-19 Pandemic Impact on Dental Practice

Introduction: The COVID-19 pandemic has had a huge impact on the dentistry industry from the initial lockdown in March 2020 to the present day, nearly one year later with dentists unable to practice during the initial lockdown, that is when revenue took the biggest hit. The study aims to examine the impact of COVID-19 on dental practices during the pandemic in Bulgaria. Material and methods: A specially developed questionnaire was distributed electronically among 138 dentists from all regions of Bulgaria. The collected primary statistical information was entered and processed with the statistical package SPSS Statistics 19.0 Results: Statistical analyzes of the questionnaire show that (62,32%±4,12) of dentists say COVID-19 made no impact on their decision to retire or continue practicing; 43% of respondents predict revenue or costs will be the biggest challenge facing their practice in 2021. Part of dentists (34.78 % ± 4,05) believe that COVID-19 allowed them to learn more about infection control. Most of the respondents (87.68% ± 2.79) agree their income was lower in April to September of 2020 compared to 2019. More than half of dentists (61.59 % ± 4.14) believe Covid 19 has not impacted the products or services they offer. The majority of the participants (84.78 % ± 3.05) did not perform non-emergency procedures during the pandemic. Conclusion: Despite the numerous disadvantages caused by the COVID-19 pandemic, our survey shows dentists have found ways to adapt and succeed. Introduction: The COVID-19 pandemic has had a huge impact on the dentistry industry from the initial lockdown in March 2020 to the present day, nearly one year later with dentists unable to practice during the initial lockdown, that is when revenue took the biggest hit. The study aims to examine the impact of COVID-19 on dental practices during the pandemic in Bulgaria. Material and methods: A specially developed questionnaire was distributed electronically among 138 dentists from all regions of Bulgaria. The collected primary statistical information was entered and processed with the statistical package SPSS Statistics 19.0 Results: Statistical analyzes of the questionnaire show that (62,32%±4,12) of dentists say COVID-19 made no impact on their decision to retire or continue practicing; 43% of respondents predict revenue or costs will be the biggest challenge facing their practice in 2021. Part of dentists (34.78 % ± 4,05) believe that COVID-19 allowed them to learn more about infection control. Most of the respondents (87.68% ± 2.79) agree their income was lower in April to September of 2020 compared to 2019. More than half of dentists (61.59 % ± 4.14) believe Covid 19 has not impacted the products or services they offer. The majority of the participants (84.78 % ± 3.05) did not perform non-emergency procedures during the pandemic. Conclusion: Despite the numerous disadvantages caused by the COVID-19 pandemic, our survey shows dentists have found ways to adapt and succeed.

Effect of Surfosept and Deconex® 53 Disinfectant Agents on the Accuracy and Dimensional Stability of Panasil Dental Impression Materials: An Experimental Study

Materials and Methods

This in vitro study was performed on 30 dental casts. The samples were divided into one control group and two experimental groups to be disinfected with Surfosept (1%) and Deconex® 53 (2%) using a sequential sampling method (10 per group). The impressions in the experimental groups (i.e., Surfosept and Deconex® 53) were rinsed and dried; then, the disinfectant was sprayed on the impressions and remained for 30 seconds before pouring with stone. In the control group, the impressions were only rinsed and dried and were poured in 10 minutes. Cast dimensions were measured by a profile projector device, and the mean values obtained from the experimental groups were compared with those of the control group.

Results

There were no significant differences among the groups regarding the height of the resulting dies without undercut (P=0.62). Moreover, there was no significant difference among the groups regarding the distance between the two dies (P=0.77). However, the diameter of the dies with undercut and without undercut was different significantly among the control and experimental groups (P < 0.005).

Conclusion

In general, no significant difference was encountered between dimensional stability and accuracy of the dental impressions using Surfosept and Deconex® 53 in this study.

Use of Photosensitizer, Glutaraldehyde, alcohol and Ultrasonics in disinfection of polished and rough surfaces of self-curing polymethyl methacrylate denture base material

AIM

To assess the effectiveness of chemical, ultrasonic and photodynamic therapy (PDT) mediated disinfection against in-vitro biofilms colonized with C. albicans, S. oralis, and S. aureus on surfaces of PMMA (polymethylmethacrylate) denture base material.

MATERIALS AND METHODS

Fifty plates of PMMA were prepared with two different surface topography (rough and polished) analyzed by profilometry. Provenance culture (ATCC) of C. albicans, S. oralis, and S. aureus were inoculated on specimens and exposed to disinfection. The disinfection included Rosebengal (RB) 5 μM activated by a red LED, 2% glutaraldehyde, 70% Isopropyl alcohol, ultrasonic disinfection, and saline solution as a control. The antimicrobial efficacy was assessed by subsequently calculating viable counts after disinfection. The data were analyzed using analysis of variance (ANOVA) and Tukey's Post Hoc test.

RESULTS

The unpolished surface demonstrated the highest average surface roughness As 5.32±0.36 (μm) and root mean square roughness Rr 7.22±0.81 (μm) compared to the polished surface. Intergroup comparison demonstrated polished and rough PMMA plate disinfected with rose bengal, glutaraldehyde and alcohol-based disinfection exhibited comparable reduction against C. albicans and S. oralis CFU/mL (log10) (p>0.05). Whereas, this reduction was significantly higher on the rough and polished surface of PMMA when disinfected using ultrasounds for 30 sec (p<0.05). Rose Bengal was the most effective method of disinfection against S. aureus both on polished (0.17±0.13) and rough (0.44±0.22) denture plates (p<0.05).

CONCLUSION

The ultrasonic disinfection was most effective in reducing viable microbial counts. RB mediated PDT exhibited a more substantial reduction of the colonies of S.aureus.

Study of Knowledge of Hand Disinfection and Dental Impressions in Everyday Practice among Dental Students during a Pandemic by Coronavirus Disease 2019

BACKGROUND: Dentistry is risky for acquiring and spreading a lot of infections. Patients in dental practice, especially those treated with dental prostheses, are at high risk both for acquisition and as a source of infectious diseases. AIM: Our study aims to estimate the level of knowledge about transmission of infections, hygienic disinfection of hands, and dental impressions among dental students during a pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)/coronavirus disease 2019 (COVID-19). MATERIALS AND METHODS: An online anonymous survey was conducted among 106 students of dental medicine from the Faculty of Dental Medicine - Plovdiv, Bulgaria. RESULTS: According to 8.5% of students, hands are a factor for transmission of infections only if they are visibly contaminated and 2.8% do not think that hands are a factor. 19.3% believe that dental impressions could be a factor in transmitting microorganisms from the dentist to the dental technicians only if they are visibly contaminated and 1.8% deny this possibility. CONCLUSION: In our country, it is necessary to be done and implement in practice a protocol for disinfection of impressions and prostheses, as they are epidemiological factors for the transmission of microorganisms between the dental office and the dental laboratory. The results in practice, after the implementation of the protocol, should be checked regularly.

Ions-induced gelation of alginate: Mechanisms and applications

Alginate is an important natural biopolymer and has been widely used in the food, biomedical, and chemical industries. Ca²⁺-induced gelation is one of the most important functional properties of alginate. The gelation mechanism is well-known as egg-box model, which has been intensively studied in the last five decades. Alginate also forms gels with many other monovalent, divalent or trivalent cations, and their gelation can possess different mechanisms from that of Ca²⁺-induced gelation. The resulted gels also exhibit different properties that lead to various applications. This study is proposed to summarize the gelation mechanisms of alginate induced by different cations, mainly including H⁺, Ca²⁺, Ba²⁺, Cu²⁺, Sr²⁺, Zn²⁺, Fe²⁺, Mn²⁺, Al³⁺, and Fe³⁺. The mechanism of H⁺-induced gelation of alginate mainly depends on the protonation of carboxyl groups. Divalent ions-induced gelation of alginate show different selection towards G, M, and GM blocks. Trivalent ions can bind to carboxyl groups of uronates with no selection. The properties and applications of these ionotropic alginate gels are also discussed. The knowledge gained in this study would provide useful information for the practical applications of alginate.