Direct Contact Test for Evaluating Bacterial Growth on Machined and Rough Surface Implants: An In Vitro Study

Marginal Bone Loss in Internal Conical Connection Implants Placed at the Crestal and Subcrestal Levels before Prosthetic Loading: A Randomized Clinical Study

The vertical position concerning the bone in which the implants are placed has been related as one of the factors causing marginal bone loss. The objective of this study was to evaluate the bone loss that occurs before prosthetic loading around tapered internal connection (CIC) implants placed at the crestal (C) and subcrestal (S) levels. Method: A randomized clinical trial (RCT) was carried out, with a sample size of 62 implants placed in 27 patients who underwent radiological controls on the day of placement, at one month, and at 4 months, and stability was measured by resonance frequency analysis (RFA) on three occasions. Results: Bone loss in implants C and S from the time of placement (T0) and the month after (T1) was not significant (p = 0.54) (C = 0.19 mm and S = 0.15 mm). The difference between one month (T1) and four months (T2) (C = 0.17 mm and S = 0.22 mm) was not significant either (p = 0.26). The difference between the day of placement (T0) and the third and last measurement (T2) was almost null (p = 0.94) (C = 0.35 mm and S = 0.36). The overall success rate of the implants was 97.8%. The stability of the implants measured with RFA went from 70.60 (T0) to 73.16 (T1) and 74.52 (T2). Conclusions: No significant differences were found in the bone loss for implants placed at the C and S levels. The millimeters of bone loss detected in both vertical positions did not have a significant impact on the stability of the implants.

In vitro Investigation of the Antimicrobial Activity of Mouth Washes Incorporating Zein-Coated Magnesium Oxide Nanoparticles

PURPOSE

This in vitro study was undertaken to investigate the antimicrobial effect of distinctive oral mouth washes after the addition of zein-coated (Magnesium oxide) MgO nanoparticles on exemplary of some oral microorganisms.

MATERIALS AND METHODS

Three hundred and twelve samples were used in this study. A set of five concentrations of MgO nanoparticles with zein and without zein-coating were incorporated into three oral mouth washes: Listerine zero, Listerine total control and Oral B in the mass percentages of 0.3%, 0.5%, 1%, 2%, 5% and 10%, in addition to controls with no MgO nanoparticles. The antimicrobial effect of three mouth washes with variable concentrations of MgO was tested against the following organisms: Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis and Candida albicans using the disc diffusion test (DDT) and direct contact test (DCT). Data were analyzed using one-way ANOVA statistical test.

RESULTS

The tested mouthwashes with zein-coated MgO nanoparticles showed significant differences of antimicrobial activity on S. mutans, S. aureus, E. faecalis, and C. albicans in the disc diffusion test. While in the DCT, all tested mouthwashes with MgO nanoparticles with and without zein coating showed antimicrobial activity on all tested microorganisms.

CONCLUSION

Zein-coated MgO nanoparticles may be considered as a potential antimicrobial agent when added to oral mouthwashes. Future analysis, including in vivo studies, is required in order to incorporate zein/MgO nanoparticles into oral mouthwashes that may improve its antibacterial property.

Clinical Implications of Polymicrobial Synergism Effects on Antimicrobial Susceptibility

With the development of next generation sequencing technologies in recent years, it has been demonstrated that many human infectious processes, including chronic wounds, cystic fibrosis, and otitis media, are associated with a polymicrobial burden. Research has also demonstrated that polymicrobial infections tend to be associated with treatment failure and worse patient prognoses. Despite the importance of the polymicrobial nature of many infection states, the current clinical standard for determining antimicrobial susceptibility in the clinical laboratory is exclusively performed on unimicrobial suspensions. There is a growing body of research demonstrating that microorganisms in a polymicrobial environment can synergize their activities associated with a variety of outcomes, including changes to their antimicrobial susceptibility through both resistance and tolerance mechanisms. This review highlights the current body of work describing polymicrobial synergism, both inter- and intra-kingdom, impacting antimicrobial susceptibility. Given the importance of polymicrobial synergism in the clinical environment, a new system of determining antimicrobial susceptibility from polymicrobial infections may significantly impact patient treatment and outcomes.

Antimicrobial properties, compressive strength and fluoride release capacity of essential oil-modified glass ionomer cements-an in vitro study

OBJECTIVES

This study was designed to investigate the antimicrobial properties, compressive strength and fluoride release capacities of high-viscous glass ionomer cements (GICs) after incorporation of cinnamon and thyme essential oils.

MATERIALS AND METHODS

Experimental-modified GICs were prepared by incorporation of thyme and cinnamon essential oils into the liquid phase of the cement at 5 and 10% v/v. Antimicrobial activity against selected microorganisms (Streptococcus mutans and Candida albicans) was done using direct contact test. Compressive strength of the four new formulations and control group was tested using a universal testing machine while fluoride ion release was measured by ion-selective electrode at 1, 7, 14 and 28 days. Data analysis and comparisons between groups were performed using factorial and one-way ANOVA and Tukey's tests.

RESULTS

All newly formulated GICs exhibited significantly higher inhibitory effects against both Streptococcus mutans and Candida albicans growth when compared to conventional GIC (p < 0.05). Compressive strength of 5% cinnamon-modified GIC (MPa = 160.32 ± 6.66) showed no significant difference when compared with conventional GIC (MPa = 165.7 ± 5.769) (p value > 0.05). Cumulative fluoride-releasing pattern at days 7, 14, and 28 were 10% cinnamon-GIC > 5% thyme-GIC > 5% cinnamon-GIC > 10% thyme GIC > conventional GIC.

CONCLUSIONS

Incorporation of 5% cinnamon oil into glass ionomer resulted in better antimicrobial effects against S. mutans and C. albicans and increased fluoride-release capacity without jeopardizing its compressive strength.

CLINICAL RELEVANCE

The 5% cinnamon-modified GIC appears to be a promising alternative restorative material in ART technique.

Er,Cr:YSGG laser surface treatment of gamma titanium aluminide: Scanning electron microscopy-energy-dispersive X-ray spectrometer analysis, wettability and Eikenella corrodens and Aggregatibacter actinomycetemcomitans bacteria count-in vitro study

Dental implants play an important role in oral health. Titanium dental implants must endure the complex microflora environment of the oral cavity. Moreover, bacterial infections have been considered as one of the most important factors of implant failure. The issue of dental improvement through modification of chemical composition and surface treatment has received considerable critical attention. γ-TiAl as a novo biocompatible material revealed a slower corrosion rate in biological media rather Ti-6Al-4V. The objective of this study is to investigate the effect of Er,Cr:YSGG laser on γ-TiAl in comparison with sandblasted and acid-etched samples as the control groups and machined samples.Wettability, surface roughness, surface topography, scanning electron microscopy-energy dispersive X-ray spectrometer analysis of surface and subsurface of samples were investigated and bacteria counts of two periodontal bacterial strains (Aggregatibacter actinomycetemcomitans and Eikenella corrodens) were evaluated on the Er,Cr:YSGG laser surface-treated sandblasted and acid-etched and machined samples.The results of this investigation show that Er,Cr:YSGG laser surface treatment affects surface roughness, surface topography, wettability, chemical composition of the surface and bacteria count. Scanning electron microscopy-energy dispersive X-ray spectrometer analysis of the sample revealed the increment of titanium and oxygen content and reduction of aluminum content in the surface and subsurface layer. A. actinomycetemcomitans and E. corrodens count were found from the lowest level to highest in the sandblasted and acid-etched samples, laser samples and machined samples, respectively.Using controlled parameters of Er,Cr:YSGG laser ensured no significant adverse alteration. The findings to emerge from this study revealed the significant correlation between microbial count and wettability. Furthermore, the contact angle strongly correlated with surface roughness.