Effectiveness of mouthrinses and oral prophylaxis on reduction of microorganisms count in irreversible hydrocolloid impression: an in vivo study

Infection Control Practices Among Private Practicing Dentists in Nairobi During the Pre-coronavirus Disease 2019 Period

Background: Cross-infection control is a dynamic field that requires frequent updates due to emerging diseases, advancement in technology, and scientific knowledge. Despite wide publication of guidelines, a laxity in compliance to the standard precautions for infection control by dental health-care personnel (DHCP) has been reported globally. Therefore, there is need to review previous shortcomings in order to adequately secure dental practices during the coronavirus disease 2019 (COVID-19) pandemic. The aim of the study was to determine knowledge and infection control practices by dentists in private practices. The study was done a few months before the first COVID-19 case was confirmed in Kenya. Materials and Methods: The study design was a descriptive cross-sectional study that was carried out in selected private dental clinics located in Nairobi. Data were collected using an interviewer-administered questionnaire. Convenience sampling method was utilized, while data were analyzed using SPSS 20.0.0.0. Results: A total of 71 private dentists participated in the study. Their mean age was 38 years with an age range of 27-55 years. Almost all (70, 98.6%) the dentists were able to define cross infection correctly. Majority (62, 87.3%) correctly differentiated between sterilization and disinfection, while 9 (12.7%) had difficulties. Most (68, 95.8%) of the respondents were aware of the standard precautions for cross-infection control. All participants used face masks and gloves. About half of them (38, 54%) practiced hand washing after removal of gloves and 31 (43.7%) before and after wearing of gloves, while 2 (2.8%) washed hands only before wearing gloves. Only 31 (42.3%) and 26 (36.6%) participants reported use of rubber dam isolation and impervious barrier, respectively. All the dentists reported disposal of sharps into especially labeled containers, while about half reported use of disposable suction traps and amalgam separators. Conclusion: The dentists had a good knowledge on various aspects of infection control measures that were studied. Use of basic personal protective equipment was widely practiced. There were irregularities in hand hygiene, use of rubber dam, surface barriers, and waste management. The work highlights that many dentists were unprepared to manage infectious risk during the COVID-19 outbreak, which justified the closure of the dental facilities. Development of strategies to promote adequate and safe practice is highly recommended.

The influence of the negative ion powder on the properties of alginate impression materials

This paper investigated the effects of different contents of negative ion powder on the antibacterial activity and mechanical properties of the alginate impression materials. The cytotoxicity of the negative ion powder was evaluated. The antibacterial rate was evaluated by the plate count method, and the mechanical properties, including the gelation time, elastic recovery, compressive strain and compressive strength were characterized by standards method. MTT assay was used to evaluate the cytotoxicity of the negative ion powder. When the content of negative ion powder was 1-2%, the antibacterial rate could be up to 90-100%. It had no significant effect on the mechanical properties of the alginate impression materials when the added content of negative ion powder was less than 2% (p>0.05). The results of the MTT assay indicated that the material is noncytotoxic. The optimal adding ratio of negative ion powder is 1-2%.

A simple and effective method for addition silicone impression disinfection

PURPOSE

Although dental impression disinfection is determinant to reduce the cross-infection risk, some studies have shown that, in real practice, the disinfection procedures vary considerably. Thus, the aim of this study was to evaluate the antimicrobial effectiveness and the impact on the dimensional stability of addition silicone' impressions of water wash and the most clinically used disinfection solutions: 3% hydrogen peroxide, commercial disinfectant MD520 (Durr) and 1% and 5.25% sodium hypochlorite.

MATERIALS AND METHODS

For this investigation, dental impressions were taken on 16 volunteer dental students. The antimicrobial effectiveness of each procedure was evaluated by pour plate method. The dimensional stability was evaluated using a standardized stainless-steel model, according to ANSI/ADA nº19 specification.

RESULTS

The study results showed that water wash does not alter the dimensional stability of addition silicone impressions but doesn't reduce the microbial load of the material (P>.05). On the other hand, addition silicone disinfection by immersion with 3% hydrogen peroxide, MD520 (Durr), or sodium hypochlorite at 1% and 5.25% does not alter the dimensional stability significantly but reduces > 99.9% of the microbial load of the impressions (P<.001).

CONCLUSION

Addition silicone impressions should always be disinfected after water wash in order to reduce effectively the cross-infection risk. All disinfectants tested showed high antimicrobial efficiency without significant changes in three-dimensional shape of impressions. Hydrogen peroxide and sodium hypochlorite are of particular importance because are easily accessible in dental setting. The less explored hydrogen peroxide could be a valuable alternative for silicone impressions disinfection.