Evaluation of antimicrobial property of modified acrylic resin-containing cetylpyridinium chloride

Effect of attachment flash on clear aligner force delivery: an in vitro study

BACKGROUND

The introduction of auxiliaries such as composite attachment has improved the force delivery of clear aligner (CA) therapy. However, the placement of the attachment may give rise to a flash, defined as excess resin around the attachment which may affect CA force delivery. This in vitro study aims to determine the differences in the force generated by the attachment in the presence or absence of flash in CA.

MATERIALS AND METHODS

Tristar Trubalance aligner sheets were used to fabricate the CAs. Thirty-four resin models were 3D printed and 17 each, were bonded with ellipsoidal or rectangular attachments on maxillary right central incisors. Fuji Prescale pressure film was used to measure the force generated by the attachment of CA. The images of colour density produced on the films were processed using a calibrated pressure mapping system utilising image processing techniques and topographical force mapping to quantify the force. The force measurement process was repeated after the flash was removed from the attachment using tungsten-carbide bur on a slow-speed handpiece.

RESULTS

The intraclass correlation coefficient showed excellent reliability (ICC = 0.96, 95% CI = 0.92-0.98). The average mean force exerted by ellipsoidal attachments with flash was 8.05 ± 0.16 N, while 8.11 ± 0.18 N was without flash. As for rectangular attachments, the average mean force with flash was 8.48 ± 0.27 N, while 8.53 ± 0.13 N was without flash. Paired t-test revealed no statistically significant difference in the mean force exerted by CA in the presence or absence of flash for both ellipsoidal (p = 0.07) and rectangular attachments (p = 0.41). Rectangular attachments generated statistically significantly (p < 0.001) higher mean force than ellipsoidal attachments for flash and without flash.

CONCLUSION

Although rectangular attachment generated a significantly higher force than ellipsoidal attachment, the force generated by both attachments in the presence or absence of flash is similar (p > 0.05).

Exploring the Effect of Cetylpyridinium Chloride Addition on the Antibacterial Activity and Surface Hardness of Resin-Based Dental Composites

The aim of this study was to evaluate the effect of cetylpyridinium chloride (CPC) addition on the antibacterial and surface hardness characteristics of two commercial resin-based dental composites (RBDCs). A total of two hundred and seventy (n = 270) specimens from Filtek Z250 Universal and Filtek Z350 XT flowable RBDCs were fabricated with the addition of CPC at 2 %wt and 4 %wt concentrations to assess their antibacterial activity using the agar diffusion test and direct contact inhibition test, and their surface hardness using the Vickers microhardness test after 1 day, 30 days, and 90 days of aging. A surface morphology analysis of the specimens was performed using a scanning electron microscope (SEM). The RBDCs that contained 2 %wt and 4 %wt CPC demonstrated significant antibacterial activity against Streptococcus mutans up to 90 days, with the highest activity observed for the 4 %wt concentration. Nevertheless, there was a reduction in antibacterial effectiveness over time. Moreover, compared to the control (0 %wt) and 2 %wt CPC groups, the universal RBDCs containing 4 %wt CPC exhibited a notable decrease in surface hardness, while all groups showed a decline in hardness over time. In conclusion, the satisfactory combination of the antibacterial effect and surface hardness property of RBDCs was revealed with the addition of a 2 %wt CPC concentration.

Effect of antimicrobial agents on the oral microflora in patients undergoing fixed orthodontic therapy-An ex vivo comparative analysis

Aim:

To evaluate and compare the efficacy of Ozonated Olive Oil Gel, Chlorhexidine gel, and Amflor (Fluoridated) mouthwash on reducing the count of Streptococcus mutans and Lactobacillus in patients undergoing fixed orthodontic therapy evaluated at different time intervals.

Methods:

Sixty patients undergoing orthodontic treatment were randomly divided into three groups (n = 20) based on antimicrobial agents used (Group 1: Ozonated olive oil gel; Group 2: Chlorhexidine gel; Group 3: Fluoridated mouthwash). Elastomeric modules from brackets were collected at T₀ (Fresh samples) and T₁ (2^nd week) and T₂ (4^th week) for assessment of the microbial growth. These collected modules were cultured and evaluated for the presence of Streptococcus Mutans and Lactobacilli and numbers of colonies were counted at each interval. Data obtained was subjected to statistical analysis using SPSS software (Version 20.0). Level of significance was kept at 5%. Intra-group and inter-group comparison between pretreatment, 2^nd week and 4^th week was done for each group using Wilcoxon signed rank test and Mann–Whitney U test.

Results:

There was presence of Streptococcus Mutans and Lactobacilli during orthodontic treatment which progressively increased from T_o to T₁ and then declined from T₁ to T_2. The colony counts were maximum for Fluoridated mouthwash and least for Chlorhexidine and the results were statistically significant (P < 0.05).

Conclusion:

All three antimicrobial agents used were effective against Streptococcus mutans and Lactobacillus. Chlorhexidine proved to be more efficacious whereas Fluoridated mouthwash proved to be least effective against both Streptococcus mutans and Lactobacillus bacteria.