Evaluation of antibiofilm effect of vancomycin, melatonin, and boric acid combination on caries due to microleakage under prosthetic restoration

Abstract

Aims: Drug-resistant oral bacteria causing dental caries under prosthetic restorations have become a significant clinical challenge that needs to be addressed. This study aims to demonstrate the antibiofilm effect of vancomycin (VAN) combined with melatonin (MEL) and boric acid (BOR) against biofilm formation caused by Escherichia coli (E. coli) and Lactobacillus acidophilus (L. acidophilus) on dentin of tooth surfaces under restorations due to microleakage. Methods: Extracted human teeth, free from caries, resorption, or fractures, were collected by slicing 2 mm dentin discs. A total of 64 dentin discs were inoculated with E. coli and L. acidophilus and randomly assigned to five experimental groups: MEL, BOR, MEL+VAN, BOR+VAN, and MEL+BOR+VAN, along with a control group. Antibiofilm activity and combination indices were analyzed using the MTT viability test and the Chou-Talalay method, respectively. The biofilm structure was examined using scanning electron microscopy. Results: MEL and VAN demonstrated antimicrobial effects against E. coli and L. acidophilus bacteria in unary combinations, while BOR showed ineffectiveness. However, a notable synergistic interaction was observed in the binary combinations of VAN. Interestingly, a significant synergistic effect (CI<1) was noted in the triple combination against both bacterial species (p<0.05). Upon examining this effect within the triple combination, it became apparent that VAN exhibited a Favorable Dose Reduction Index (DRI>1) (p<0.05). When evaluating these synergistic and dose reduction results alongside scanning electron microscopy image analysis, it can be concluded that the triple combination of MEL+BOR+VAN likely induces the most optimal antibiofilm effect on dental caries bacteria.  Conclusion: The tendency of cements used in the luting of prosthetic restorations to microbial colonization and their tendency to dissolve in oral fluids increases the formation of caries under crowns and bridges due to microleakage, which may lead to tooth loss. Combining melatonin and boric acid with vancomycin may offer a potential treatment option for preventing this problem, as it exhibits strong antimicrobial properties. Thanks to this combination, the microbial load in the areas under prosthetic restorations can be reduced, and both the development of caries and the progression of existing active caries can be stopped. Thus, oral infections resulting from microleakage and their associated systemic complications can be reduced, and the longevity of restorations, as well as patient comfort, can be increased.

Keywords

• Melatonin
• boric acid
• vancomycin
• dentin
• caries

Supporting Institution

not applicable

Project Number

2025-GOKAEK-257_2025.04.09_443

Ethical Statement

This study received approval from the ethics committee of the Faculty of Medicine at Yozgat Bozok University (2025-GOKAEK-257_2025.04.09_443), and all experiments were conducted in accordance with the ethical guidelines of the Helsinki Declaration.

Thanks

not applicable

Vankomisin, melatonin ve borik asit kombinasyonunun çürük önleyici etkilerinin değerlendirilmesi

Abstract

Amaç: Diş çürüklerine yol açan ilaca dirençli oral enfeksiyonlar, ele alınması gereken önemli bir klinik zorluk haline gelmiştir. Bu çalışma, vankomisinin (VAN) melatonin (MEL) ve borik asitle (BOR) birleştirilmesinin Escherichia coli ve Lactobacillus acidophilus'un diş yüzeylerindeki dentin üzerinde neden olduğu biyofilm oluşumuna karşı antibiyofilm etkisini ortaya koymayı amaçlamaktadır. Malzemeler ve yöntem: Çürük, rezorpsiyon veya kırık içermeyen yeni çekilmiş insan dişleri, 2 mm'lik dentin diskleri kesilerek toplandı. Toplam 64 dentin diski E. coli ve L. acidophilus ile aşılandı ve rastgele kontrol ve beş deney grubuna atandı: MEL, BOR, MEL+VAN, BOR+VAN ve MEL+BOR+VAN. Antibiyofilm aktivitesi ve kombinasyon indeksleri sırasıyla MTT canlılık testi ve Chou-Talalay yöntemi kullanılarak analiz edildi. Biyofilm yapısı taramalı elektron mikroskobu ile incelendi. Sonuçlar: MEL ve VAN, tekli kombinasyonlarda E. coli ve L. acidophilus bakterilerine karşı antimikrobiyal etkiler gösterirken, BOR etkisiz kaldı. Ancak, VAN'ın ikili kombinasyonlarında dikkate değer bir sinerjistik etkileşim gözlendi. İlginç bir şekilde, üçlü kombinasyonda her iki bakteri türüne karşı önemli bir sinerjistik etki (CI < 1) kaydedildi. Bu etki üçlü kombinasyon içinde incelendiğinde, VAN'ın uygun bir doz azaltma indeksi (DRI>1) sergilediği ortaya çıktı. Bu sinerjistik ve doz azaltma sonuçlarını SEM görüntü analiziyle birlikte değerlendirdiğimizde, MEL+BOR+VAN üçlü kombinasyonunun muhtemelen diş çürüğü bakterileri üzerinde en optimum antibiyofilm etkisini oluşturduğu sonucuna varılabilir. Sonuç: VAN'ın MEL ve BOR ile birleştirilmesi, diş dentinindeki bakteriyel tutulumu azaltmak için yeni bir strateji sağlayabilir.

Keywords

• Melatonin
• Borik asit
• Vankomisin
• Dentin
• Çürük

Project Number

2025-GOKAEK-257_2025.04.09_443

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