The Effect of Different Output Powers of Blue Diode Laser along with Curcumin and Riboflavin against Streptococcus mutans around Orthodontic Brackets: An In Vitro Study

Natural compounds: new therapeutic approach for inhibition of Streptococcus mutans and dental caries

Streptococcus mutans is recognized as one of the leading causes of dental caries, and biofilm formation by this bacterium plays a key role in dental plaque development and caries progression. Given the increasing resistance of bacteria to antibiotics and the adverse effects of some synthetic antimicrobials, the search for natural alternatives has received increasing attention. The recently published studies have demonstrated that natural compounds (NCs) such as curcumin, cinnamaldehyde, eugenol, thymol, carvacrol, epigallocatechin gallate, farnesol, catechin, inulin, menthol, apigenin, myricetin, oleanolic acid, and resveratrol, have notable antimicrobial properties and can effectively inhibit the growth of Streptococcus mutans. NCs can disrupt bacterial membrane integrity, leading to cell death, and possess the capability to inhibit acid production, which is a key factor in caries development. NCs can also interfere with bacterial adhesion to surfaces, including teeth. The attachment inhibition is achieved by decreasing the expression of adhesion factors such as gtfs, ftf, fruA, and gbpB. NCs can disrupt bacterial metabolism, inhibit biofilm formation, disperse existing biofilm, and interfere with quorum sensing and two-component signal transduction systems. Moreover, novel drug delivery platforms were used to enhance the bioavailability and stability of NCs. Studies have also indicated that NCs exhibit significant efficacy in combination therapies. Notably, curcumin has shown promising results in photodynamic therapy against S. mutans. The current review article analyzes the mechanisms of action of various NCs against S. mutans and investigates their potential as alternative or complementary therapeutic options for managing this bacterium and dental caries.

Riboflavin-Mediated Photodynamic Therapy in Periodontology: A Systematic Review of Applications and Outcomes

Background: Riboflavin (vitamin B2) has emerged as a promising photosensitizer in photodynamic therapy (PDT) due to its strong absorption of blue light and favourable safety profile. This systematic review aims to evaluate the efficacy of riboflavin-mediated PDT in periodontology, specifically examining its antimicrobial effects and potential to improve clinical outcomes compared to conventional or other PDT-based treatments. Methods: A systematic review was conducted following PRISMA guidelines. A comprehensive literature search was performed in PubMed/Medline, Embase, Scopus, and the Cochrane Library. Studies published in English within the last 10 years were considered, where riboflavin served as the primary photosensitizer for dental treatments. Data extraction focused on study design, photosensitizer concentration, light source parameters, and clinical or microbiological outcomes. The risk of bias was assessed independently by two reviewers using a predefined scoring system. Results: Ten studies met the inclusion criteria, all demonstrating a low risk of bias. Riboflavin-mediated PDT consistently reduced microbial biofilms and pathogen viability in periodontitis, peri-implantitis, and endodontic models. Although some studies reported slightly lower efficacy compared to chlorhexidine or toluidine blue-based PDT, riboflavin-mediated PDT exhibited advantages such as minimal staining, low cytotoxicity, and enhanced collagen crosslinking. However, most studies were in vitro or small-scale clinical trials, limiting conclusions on long-term effectiveness. Conclusions: Riboflavin-mediated PDT shows promise as a safe adjunctive therapy for periodontal infections. Larger, well-designed clinical trials with standardized parameters and extended follow-up are needed to further evaluate its efficacy and optimize treatment protocols for routine clinical application.

Advanced Lasers and Their Applications in Dentistry

The development of laser technology has revolutionized dentistry, offering complementary and alternative approaches to traditional techniques. Lasers have been successfully integrated into various dental procedures, enhancing treatment outcomes and patient care. Several types of lasers can increase the acid resistance of enamel, thus preventing caries. Laser fluorescence has been utilized for the pre-operative diagnosis of dental caries, enabling early detection and effective treatment planning. The therapeutic application of lasers in caries treatment aligns with the contemporary philosophy of minimally invasive procedures. Clinicians can use laser Doppler flowmetry as a supplementary tool for pulp vitality testing by detecting pulpal blood flow. Lasers are also employed in various pulp-related interventions, such as managing dentine hypersensitivity and performing root canal therapy. These procedures benefit from the precision and reduced invasiveness provided by laser technology. Furthermore, laser fluorescence serves as an additional tool for subgingival calculus detection. High-power and low-power lasers are used in both nonsurgical and surgical therapies to treat periodontal and peri-implant diseases, oral mucosa conditions, and even cancer based on their specific properties. Lasers are also utilized to accelerate bone regeneration, promote adhesive strength, and remove ceramic brackets. In summary, laser technology has significantly impacted contemporary dentistry by facilitating early diagnosis, minimally invasive treatments, and precise operative procedures, ultimately improving patient outcomes and expanding the scope of dental practice.

Photodynamic Therapy 2.0

In 1903, Von Tappeiner and Jesionek [...].

Effect of silver diamine fluoride combined with photodynamic therapy on primary enamel microhardness

OBJECTIVES

This study aimed to assess the effect of silver diamine fluoride (SDF) combined with photodynamic therapy (PDT) on primary enamel microhardness.

MATERIALS AND METHODS

This in vitro, experimental study was conducted on 40 extracted primary molars with sound buccal/lingual surfaces. The baseline enamel microhardness of the teeth was initially measured by a Vickers hardness tester. Next, the teeth were randomly assigned to four groups (n = 10) for treatment with SDF, PDT, SDF plus PDT, and control (no intervention). After the intervention, the teeth underwent a 14-day pH-cycling, and enamel microhardness was measured again. The change in microhardness was calculated for each group, and comparisons were made by two-way ANOVA and t-test (alpha = 0.05).

RESULTS

The mean secondary microhardness of the three intervention groups was significantly higher than that of the control group (P<0.05). Despite slightly higher microhardness in SDF + PDT group, followed by the SDF group, the difference in secondary microhardness was not significant among the three intervention groups (P>0.05).

CONCLUSION

Treatment of primary enamel with SDF or PDT can increase its microhardness and enhance remineralization. However, combined use of SDF and PDT had no additional advantage over the use of SDF alone.

Comparative study of the effect of different exposure parameters of 635nm diode laser and toluidine blue O in eliminating Aggregatibacter actinomycetemcomitans biofilm from titanium implant surfaces

BACKGROUND

The aim of this study was to investigate the effects of antimicrobial photodynamic therapy (PDT) using 635 nm diode laser irradiation with an energy density of 6 to 30 J/cm2 and toluidine blue O (TBO) as a photosensitizer on the viability of Aggregatibacter actinomycetemcomitans attached to the surface of titanium implants.

MATERIALS AND METHODS

Titanium implants contaminated with A. actinomycetemcomitans were treated with TBO alone or in combination with different exposure parameters (light doses of 6 - 30 J/cm2 at 635 nm) and 0.2 % chlorhexidine (CHX). After treatment, colony forming units (CFUs)/ml were determined to assess PDT efficacy. The structure of the biofilm of A. actinomycetemcomitans was analyzed by field emission scanning electron microscopy (FESEM).

RESULTS

Under optimal conditions, the colony count was reduced by ∼90 %. Treatment with CHX was somewhat more effective (colony formation was reduced by ∼95 %), but this agent has adverse effects that can be avoided with PDT.

CONCLUSION

This study confirms the efficacy of PDT against A. actinomycetemcomitans depending on the light dose. Treatment with TBO + 635 nm diode laser has an effect that may be equivalent to that of CHX, but perhaps with fewer adverse effects.