In vitro evaluation of the effects of Ultrasound Tongue Scraper on bacteria and biofilm formation

AIM

Oral malodor is a common condition caused by some Gram-negative oral bacteria, among which are the 3 red complex bacteria (RCB). The present study investigated the effectiveness of the Ultrasound Tongue Scraper (UTS) to disrupt the structural morphology of the bacteria and their biofilm.

METHODS

While developing over 72 hours, multispecies biofilms of RCB (Porphromonas gingivalis, Tryponema denticola, Tannerella forsythia) were treated every 24 hours with 1.6-MHz ultrasound waves generated with UTS. An untreated group served as controls. Confocal laser scanning microscopy was used to determine the biofilm thickness, biomass and live : dead cell ratio at each time point (24, 48 and 72 hours). Biofilm morphology and bacteria ultrastructure were viewed using scanning/transmission electron microscopy, respectively. Data were analyzed using ANOVA and Tukey tests.

RESULTS

At each time point, the 3 variables were significantly lower in treated samples than the untreated. Significant biofilm disruption was observed in treated samples at each time period while the untreated had intact biofilm morphology. Cells in treated samples showed disrupted cell wall, cytoplasmic material, huge vacuoles and heterogeneity in electron density, while these cell organelles remained intact in untreated samples.

CONCLUSION

The UTS has an inhibitory effect on RCB and could be useful for oral malodor management.

Comparative Efficacy in Preventing Plaque Formation around Pit and Fissure Sealants: A Clinical Trial

AIM

The purpose of this study is to compare the clinical performance of an organo-selenium-containing pit and fissure sealant with that of a selenium-free sealant for clinical retention and prevention of plaque and caries development around the sealants.

MATERIALS AND METHODS

Following an in vitro study confirming the antimicrobial effect of an organo-selenium-containing pit/fissure sealant [DenteShield™ (DS)], 120 adolescents (7-20 years old) at varying caries risk status had DS sealant applied to a single tooth on the left or the right side of the dentition and UltraSeal™ XT Plus (UXT) on a corresponding tooth on the opposite side. Sealants' assessment was performed quarterly for 1 year for clinical retention, plaque, and caries formation around the sealant. Each sealant lost was replaced but considered as a failure in further analysis. McNemar's test was used to statistically analyze the outcome variables at each assessment time point.

RESULTS

While 7% and 12% plaque growth was observed around the UXT sealant at 9th and 12th months, respectively, DS exhibited 100% prevention of plaque growth. Both sealants exhibited 100% caries prevention. Clinical retention did not significantly differ between DS and UXT at all assessment time points except at 12 months when DS showed statistically significantly (p < 0.001) better retention (96%) than UXT (81%).

CONCLUSION

In this study, while both sealants are equally effective in caries prevention, DS completely prevented plaque growth around it with better clinical retention than UXT that offered only limited protection against plaque growth.

CLINICAL SIGNIFICANCE

Being antimicrobial, DS pit and fissure sealant may be the best sealant option for patients whose caries risk status is due to poor oral hygiene.

Do Products Preventing Demineralization Around Orthodontic Brackets Affect Adhesive Bond Strength?

Objective:

This study investigated the effects, on the shear bond strength of orthodontic brackets, of using an antimicrobial selenium-containing sealant (DenteShieldTM) to serve dual functions of priming enamel prior to bonding and as a protective barrier against whitespot lesion formation.

Materials and Methods:

A total of 150 extracted human premolars were randomly assigned into 10 groups (n=15/group). Stainless steel brackets were bonded with two adhesive systems (DenteShieldTM or Transbond XT) after the enamel was conditioned with a primer (DenteShieldTM or Assure Universal) or a filled resin sealant (DenteShieldTM, Pro SealTM or Opal SealTM). The specimens were stored in deionized water at 37 °C for 24 hours and debonded with a universal testing machine.

Results:

The use of DenteShieldTM adhesive to bond orthodontic brackets to the enamel surface resulted in a significantly lower (P<0.05), but clinically acceptable, shear bond strength (mean & SD: 14.5±1.6 MPa) as compared with Transbond XT group (mean & SD: 19.3±1.7 MPa). DenteShieldTM sealant used as primer resulted in shear bond strength values comparable to those of Pro SealTM and Opal SealTM. All adhesive-sealant and primer-sealant combinations tested in this study exhibited shear bond strength values greater than 9.6 MPa, sufficient for clinical orthodontic needs.

Conclusion:

DenteShieldTM sealant can serve as primer as well as anti-demineralization sealant during orthodontic treatment without adversely affecting the shear bond strength of the bracket.

Effectiveness of S-PRG Filler-Containing Toothpaste in Inhibiting Demineralization of Human Tooth Surface

OBJECTIVES

Using an established pH-cycling caries model, the authors evaluated the effectiveness of toothpastes containing Surface Pre-reacted Glass-ionomer filler (S-PRG) in preventing tooth surface demineralization.

MATERIALS AND METHODS

210 tooth blocks were randomly assigned to seven experimental groups (30 blocks/group): no treatment (A), and toothpaste containing either NaF (B), 0 wt% S-PRG (C), 1 wt% S-PRG (D), 5 wt% S-PRG (E), 20 wt% S-PRG (F) or 30 wt% S-PRG (G). Groups were subjected to 14-day demineralization for development of early caries lesions using a pH-cycling caries model. Demineralization was assessed using Quantitative Light-induced Fluorescence (QLF) and Transverse Microradiography (TMR). All pairwise contrasts (between treatments) were tested using Analysis of Variance (ANOVA), and then Tukey's HSD for multiple comparisons. All p-values are considered significant if <0.05.

RESULTS

With QLF, there was a significant (ANOVA; p<0.001) difference in mean percent fluorescence loss (∆F) observed among the groups. Relative to control, all S-PRG-containing toothpastes significantly (Tukey's; p<0.0001) inhibited demineralization at varying percentages (48.6%, 61.3%, 67.4% and 69.8% reduction with S-PRG 1%, 5%, 20% and 30% respectively). Demineralization reduction was not significant with either NaF (15.6% reduction) or 0% S-PRG (-2.5% reduction i.e. 2.5% more demineralization than the Control) when compared to control group. Mineral loss assessed using TMR followed a similar trend as fluorescence loss.

CONCLUSION

Toothpaste containing S-PRG filler can serve as an effective caries control tool. S-PRG filler-containing dentifrice to be more effective in preventing tooth demineralization than 1100 ppm fluoride provided as sodium fluoride.