Does Adding Various Accelerators to Mineral Trioxide Aggregate Have a Negatively Effect on Push-Out Bond Strength?

Does adding accelerators to Mineral Trioxide Aggregate affect the shear bond strength?

Amaç: Bu çalışmada, farklı hızlandırıcı ilave edilen Mineral Trioksit Agregat’ın (MTA) kompozite farklı sertleşme sürelerinde makaslama bağlanma dayanımının (MBD) değerlendirilmesi amaçlanmıştır. Gereç ve Yöntemler: Merkezi boşluklara sahip 120 adet akrilik blok 4 ana gruba ayrıldı. 1. grup (kontrol); sadece MTA, 2, 3 ve 4. grup ise sırasıyla %10 kalsiyum klorür (CaCl2), %23,1 kalsiyum laktat glokonat (CLG) ve %15 disodyum hidrojen fosfat (Na2HPO4) ile karıştırılmış MTA içermektedir. Her grup 2 saat 45 dakika , 24 saat ve 96 saat sertleşme süresine göre 3 alt gruba ayrıldı. Bekleme süreleri tamamlandıktan sonra adeziv sistem (Clearfil SE Bond, Kuraray) ve kompozit rezin (Clearfil Majesty, Kuraray) işlemleri tamamlanan örneklere evrensel test cihazında MBD testi uygulandı. Elde edilen verilerinin karşılaştırmasında, tek yönlü varyans analizi (ANOVA) ve Tukey HSD testleri kullanıldı. Bulgular: Hızlandırıcısız MTA en yüksek ortalama MBD değeri sergiledi. Hızlandırıcısız MTA, hızlandırıcı olarak CLG ve Na2HPO4 eklenen MTA ile kıyaslandığında aralarındaki fark anlamlı bulundu (p<0.0001). Başlangıç sertleşme süresinde alt gruplar arasında istatistiksel olarak anlamlı farklılık gözlenmedi (p>0,05), diğer sertleşme sürelerinde fark anlamlı bulundu (p<0,05). MTA’ya hızlandırıcı olarak CLG ve Na2HPO4 ilavesinin tüm sürelerde MBD değerlerini azalttığı, CaCl2 ilavesinin ise 96 saatin ardından MBD değerini anlamlı olarak yükselttiği gözlendi. Sonuç: MTA içerisine hızlandırıcı eklemek MBD değerini düşürmektedir. Ancak MTA’ya hızlandırıcı olarak %10 CaCl2 eklemek 96 saatin ardından yapılacak restoratif işlemlerde pozitif bağlantı sonuçları ortaya çıkarabilir.

Biological properties of lithium-containing surface pre-reacted glass fillers as direct pulp-capping cements

OBJECTIVE

Surface pre-reacted glass fillers (S-PRG) can release different types of ions and in our previous study, we modified these fillers with lithium chloride (S-PRG/Li-100 mM) to induce reparative dentin formation by activating the Wnt/β-catenin signaling pathway. Here, we assessed the biological performance of S-PRG/Li-100 mM and compared it with that of mineral trioxide aggregate (MTA) and S-PRG without additives.

METHODS

In vivo studies were conducted on male Wistar rats using Masson's trichrome staining in pulp-capped molars. The test materials were implanted subcutaneously to evaluate their capacity for vascularization and biocompatibility. The ability of the test materials to form apatite was tested by immersing them in simulated body fluid. Rhodamine-B staining was conducted to assess their sealing ability in bovine teeth, while their antibacterial activity was evaluated against Streptococcus mutans and Lactobacillus casei in terms of colony-forming units and by live/dead staining.

RESULTS

Masson's trichrome staining and tissue-implantation tests confirmed the biocompatibility of S-PRG/Li-100 mM and it was similar to that of MTA and S-PRG; inflammation regression was observed 14 days after operation in the subcutaneous tissues. S-PRG/Li-100 mM promoted the formation of apatite on its surface. Both the S-PRG groups showed higher sealing capability and bactericidal/bacteriostatic activity against oral bacterial biofilms than MTA.

SIGNIFICANCE

Lithium-containing surface pre-reacted glass cements exhibit better antibacterial and sealing capabilities than MTA, suggesting their potential as high-performance direct pulp-capping materials.

Effect of dentin and fiber post surface treatments with fumaric acid on the bonding ability of fiber posts

This study investigated the effects of fumaric acid on push-out bond strength when applied to dentin surfaces and fiber posts. The root canals of 60 mandibular premolar teeth were instrumented and obturated. After removing two thirds of filling material, teeth were prepared according to six randomized groups (n = 10/group) defined by two fiber post surface treatments (0.7% fumaric acid or 9% hydrofluoric acid) and three dentin conditioning treatments [control (no conditioning); 17% ethylenediamine tetraacetic acid (EDTA); or 0.7% fumaric acid]. After fiber post-cementation, three 1-mm thick discs were obtained from each tooth by transverse sectioning, and each disc underwent push-out bond strength testing. Data were analyzed with a one-way analyses of variance (anova) and t tests; p < .05 was considered statistically significant. Failure modes were determined by stereomicroscopy, and the surface characteristics of dentin and fiber posts were observed by scanning electron microscopy. Push-out bond strength was greater for the group in which the post surface treated with hydrofluoric acid and the dentin surface treated with fumaric acid than the nontreated dentin and hydrofluoric acid-treated post group (p < .05). There were no significant differences between other comparison pairs (p > .05). A combination of fumaric acid dentin conditioning and hydrofluoric acid fiber post treatment strengthened the bonding ability of fiber posts.

Biocompatibility of a New Antibacterial Compound and its Effect on the Mechanical Properties of Flowable Dental Composites (Animal Study)

STATEMENT OF THE PROBLEM

Recently, new compound of 3, 5-dimethyl-1-thiocarboxamide pyrazole has been composed with excellent antibacterial property. Biocompatibility and its effects on mechanical properties of dental composites should be considered before clinical use.

PURPOSE

The purpose of this study was to evaluate the biocompatibility of 3, 5-dimethyl-1-thiocarboxamide pyrazole as a new antibacterial compound and its effect on the mechanical properties of dental composites.

MATERIALS AND METHOD

In this experimental study, a new antibacterial compound was synthesis by reaction between Thiosemicarbazide and 2, 4-Pentandione and tested on thirty male albino Wistar rats weighting 200-250gr. Rats were randomly divided into 3 groups of 10, each rat received 3 implants of 3,5-dimethyl-1-thiocarboxamide pyrazole, penicillin v and empty polyethylene tube. A pathologist, who was unaware of types of tested materials and timing, performed the examination of specimens. The depth of cure and flexural strength of resin composite was measured using Iso4049 standard technique. Compressive strength was determined according to Iso9917 standard.

RESULTS

This compound was biocompatible and there was no significant difference in flexural strength and compressive strength of the composites containing 1% of this compound with the control group (p> 0.05).

CONCLUSION

The 3, 5-dimethyl-1-thiocarboxamide pyrazole with a concentration of 1% in flowable composites can be very effective in preventing secondary caries.