Evaluation of the Efficacy of LASER, Desensitizing Agents, and their Combined Effect on Dentinal Hypersensitivity in Bicuspids: In Vitro Study

Aim

This study aimed to know the potential of diode light amplification by stimulated emission of radiation (LASER) and desensitizing agents on blocking the dentinal tubules, which may further help in reducing the most common dental problem named dentinal hypersensitivity (DH).

Materials and Methods

Sixty human permanent bicuspids were selected, and preparation was performed in the cervical region measuring 2.5 mm × 2.5 mm × 2.5 mm, followed by acid etching for 15 seconds. These are then divided according to the groups mentioned: group 1-nano-hydroxyapatite (HA) was applied for 15 minutes; group 2-biosilicate was applied for 15 minutes; group 3-diode LASER application was performed twice for 60 seconds in noncontact mode; group 4-nano-HA plus diode LASER application; and group 5-biosilicate plus diode LASER application. The same procedure was followed on the 1st, 7th, and 14th days and then rinsed and stored in artificial saliva, and the saliva was changed every 24 hours. The dentinal tubular occlusion was observed under a scanning electron microscope (SEM) after the 14th day.

Result

The maximum dentinal tubular occlusion was observed in group 4, where nano-HA and diode LASER application was performed.

Conclusion

All the investigated treatment groups have promising occluding potential, but the maximum was found in group 4 >group 5 >group 3 >group 1 >group 2. LASER plus desensitizing together prove to be potent and effective in reducing dentinal tubular diameter.

Remineralization of caries-affected dentin and color stability of teeth restored after treatment with silver diamine fluoride and bioactive glass-ceramic

OBJECTIVES

The aim of this study was to evaluate the microhardness of caries-affected dentin and color stability of teeth restored after treatments with silver diamine fluoride (SDF) associated to potassium iodide (KI) and Biosilicate.

MATERIAL AND METHODS

Different samples from bovine teeth were obtained. For color readings, 80 cavities (6 mm × 6 mm × 2 mm) were prepared, and for microhardness, teeth were flattened into dentine to obtain 40 samples. All samples were submitted to cariogenic challenge and separated in 4 groups, according to the treatment used: 12% SDF + KI; 38% SDF; Biosilicate and control (no treatment). Cavities were restored with resin-modified glass-ionomer cement (RMGIC, Vitremer, 3 M ESPE) or composite resin (CR, Z350, 3 M ESPE). After restoration, the samples were submitted to thermo-mechanical cycling (TMC) for 1,200,000 cycles. Color readings (EasyShade, Vita) were performed after restorations, after TMC, and 30 days after TMC. Knoop microhardness was evaluated on the planned samples before and after cariogenic challenge, after treatments, and after 30 days. Scanning electron microscopy (SEM) evaluated the dentine surface after treatments. Data were analyzed (ANOVA, Bonferroni, p < .05).

RESULTS

The results showed a higher color alteration for RMGIC than CR. The time of analysis was significant (p < .05) for the 12% SDF + KI and control group. There was no difference (p < .05) in microhardness between groups. However, there was evidence of dentin remineralization after treatments.

CONCLUSIONS

It was concluded that the samples treated with Biosilicate resulted in a color alteration similar to control. The treatments presented dentin remineralizing potential for microhardness, below the demineralization level, caused by the cariogenic challenge.

CLINICAL RELEVANCE

Considering the remineralizing potential presented by Biosilicate, this agent is a promising alternative that overcomes the SDF adverse effects such as tooth staining.

Effect of bioactive Biosilicate® /F18 glass scaffolds on osteogenic differentiation of human adipose stem cells

This study evaluated the gene expression profile of the human adipose-derived stem cells (hASCs) grown on the Biosilicate^® /F18 glass (BioS-2P/F18) scaffolds. hASCs were cultured using the osteogenic medium (control), the scaffolds, and their ionic extract. We observed that ALP activity was higher in hASCs grown on the BioS-2P/F18 scaffolds than in hASCs cultured with the ionic extract or the osteogenic medium on day 14. Moreover, the dissolution product group and the control exhibited deposited calcium, which peaked on day 21. Gene expression profiles of cell cultured using the BioS-2P/F18 scaffolds and their extract were evaluated in vitro using the RT² Profiler polymerase chain reaction (PCR) microarray on day 21. Mineralizing tissue-associated proteins, differentiation factors, and extracellular matrix enzyme expressions were measured using quantitative PCR. The gene expression of different proteins involved in osteoblast differentiation was significantly up-regulated in hASCs grown on the scaffolds, especially BMP1, BMP2, SPP1, BMPR1B, ITGA1, ITGA2, ITGB1, SMAD1, and SMAD2, showing that both the composition and topographic features of the biomaterial could stimulate osteogenesis. This study demonstrated that gene expression of hASCs grown on the scaffold surface showed significantly increased gene expression related to hASCs cultured with the ionic extract or the osteogenic medium, evidencing that the BioS-2P/F18 scaffolds have a substantial effect on cellular behavior of hASCs.

Drug-delivery Ca-Mg silicate scaffolds encapsulated in PLGA

The aim of this work is to develop dual-functional scaffolds for bone tissue regeneration and local antibiotic delivery applications. In this respect, bioresorbable bredigite (Ca₇MgSi₄O₁₆) porous scaffolds were fabricated by a foam replica method, loaded with vancomycin hydrochloride and encapsulated in poly lactic-co-glycolic acid (PLGA) coatings. Field emission scanning electron microscopy, Archimedes porosimetry and Fourier-transform infrared spectroscopy were used to characterize the structure of the scaffolds. The drug delivery kinetics and cytocompatibility of the prepared scaffolds were also studied in vitro. The bare sample exhibited a burst release of vancomycin and low biocompatibility with respect to dental pulp stem cells based on the MTT assay due to the fast bioresorption of bredigite. While keeping the desirable characteristics of pores for tissue engineering, the biodegradable PLGA coatings modified the drug release kinetics, buffered physiological pH and hence improved the cell viability of the vancomycin-loaded scaffolds considerably.

Bioactive tri/dicalcium silicate cements for treatment of pulpal and periapical tissues

Over 2500 articles and 200 reviews have been published on the bioactive tri/dicalcium silicate dental materials. The indications have expanded since their introduction in the 1990s from endodontic restorative and pulpal treatments to endodontic sealing and obturation. Bioactive ceramics, based on tri/dicalcium silicate cements, are now an indispensable part of the contemporary dental armamentarium for specialists including endodontists, pediatric dentists, oral surgeons andfor general dentists. This review emphasizes research on how these materials have conformed to international standards for dental materials ranging from biocompatibility (ISO 7405) to conformance as root canal sealers (ISO 6876). Potential future developments of alternative hydraulic materials were included. This review provides accurate materials science information on these important materials. STATEMENT OF SIGNIFICANCE: The broadening indications and the proliferation of tri/dicalcium silicate-based products make this relatively new dental material important for all dentists and biomaterials scientists. Presenting the variations in compositions, properties, indications and clinical performance enable clinicians to choose the material most suitable for their cases. Researchers may expand their bioactive investigations to further validate and improve materials and outcomes.

Bioactive glass ceramic can improve the bond strength of sealant/enamel?

AIM

Evaluate the influence of enamel pre-treatment using Biosilicate, associated or not to other treatments; on the bond strength (BS) of pit-and-fissure sealant, with or without saliva contamination.

METHODS

Ninety slices (4 mm × 4 mm) were obtained from 30 bovine incisors. Each slice was embedded in acrylic resin with their buccal surface exposed and polished to obtain a flat enamel surface. Half of them were contaminated with human saliva. All specimens were randomly divided into five groups (n = 9) according to the surface pre-treatment tested: acid etching (AE); AE + Biosilicate (B); AE + B + total-etch adhesive (Ad); Biosilicate; control (no treatment). Then, a 1 mm layer of sealant (Clinpro XT Varnish, 3M ESPE) was applied; and to provide support, a composite resin (Opallis, FGM) block was built up over it. Samples were thermocycled (500 cycles/5-55 °C) and sectioned obtaining sticks (1 × 1 × 10 mm) for microtensile BS testing (0.5 mm/min). Data were analysed with two-way ANOVA, Bonferroni test, p < 0.05. Failure patterns were evaluated using a stereomicroscope.

RESULTS

There was no difference among contaminated and non-contaminated groups, and between non-contaminated groups (p > 0.05). When contaminated, AE + B + Ad Group showed the highest BS values, differing (p < 0.05) from B Group and Control; similar between them (p > 0.05). Cohesive fractures were found in AE + B + Ad Group, submitted or not to contamination.

CONCLUSIONS

Since a surface pre-treatment was used, whether Biosilicate was applied or not, the sealant/enamel BS was the same in saliva-contaminated or non-contaminated enamel.

Evaluation of Crystallized Biosilicate in the Reconstruction of Calvarial Defects

INTRODUCTION

The objective of this study was to assess the bone repair process of crystallized Biosilicate in surgically created defects on rats' calvaria. This biomaterial was recently developed for odontological use.

MATERIALS AND METHODS

We used fifteen rats (rattus norvegicus albinus, Wistar), and two 5 mm surgical defects were performed on each of them; the defects were made with trephine drill on the calvarium region prior to the biomaterial placement. Groups were divided as follows: Group 1-defect filled with clot; Group 2-defect filled with crystallized Biosilicate. After 7, 14 and 28 days the animals were killed, the parts were retrieved and slides were prepared for histological studies.

RESULTS

Bone formation was satisfactory in all groups, with direct contact between biomaterial surface and bone and absence of infection signs. The 28 days periods showed better results, and statistically significant difference between Clot Group (90.2 %) and Biosilicate (58 %; p = 0.002) was seen, regarding presence of bone tissue on the surgical defects.

CONCLUSION

Our study revealed that defects filled with clot present better results on bone formation compared to crystallized Biosilicate, which is considered a biocompatible material with favorable osteoconductive properties.