Biochemical and immunohistochemical analysis of tissue inhibitor of metalloproteinases-1 in human sound dentin

The evolution of adhesive dentistry: From etch-and-rinse to universal bonding systems

OBJECTIVES

This review aimed at presenting the mechanisms and pitfalls of adhesion to enamel and dentin, advances in the materials science and in the development of strategies to improve hybrid layer (HL) longevity.

METHODS

Search of the literature was performed on PubMed, Scopus and Web of Science with keywords related to the structure of the dental substrate, HL degradation mechanisms and strategies to contrast them.

RESULTS

Albeit the advances in the dental materials' properties, HL degradation is still a relevant and current issue in adhesive dentistry. However, adhesive materials have become more resistant and less operator sensitive, and good adhesion is currently in the hands of every practitioner. Numerous novel strategies are being developed, able to improve the resistance of adhesive resins to degradation, their ability to infiltrate and chemically bond to dentin, to remove the unbound/residual water within the HL, reinforce the dentin collagen matrix, and inhibit endogenous metalloproteinases. Many of the strategies have turned to nature in search for powerful biomodifying compounds, and for the inspiration as to mimic naturally occurring regenerative processes.

SIGNIFICANCE

Extensive knowledge on the structure of the dental substrate and the complexity of adhesion to dentin has led to the development of improved formulations of dental adhesives and numerous valid strategies to improve the strength and longevity of the HL. Nevertheless, for many of them the road from bench to chairside still seems long. We encourage practitioners to know their materials well and use the strategies readily available to them.

Role of MMP inhibitors on levels of MMP-2 and MMP-9 in mammalian cell lines - A systematic review

Matrix metalloproteinases (MMPs) are proteolytic enzymes involved in extracellular matrix (ECM) degradation, contributing to various pathological conditions, including periapical lesions and periodontal diseases. This systematic review evaluates the inhibitory effects of different natural and synthetic MMP inhibitors on MMP-2 and MMP-9 activities in mammalian cells, which are critical enzymes implicated in ECM breakdown. A comprehensive literature search was performed across databases, including PubMed, Scopus, and Cochrane until June 2023, following PRISMA guidelines. The Office of Health Assessment and Translation (OHAT) risk of bias tool was used for quality assessment, revealing a low risk of bias across all studies. Our findings demonstrate that both natural and synthetic MMP inhibitors significantly reduce MMP-2 and MMP-9 activities in mammalian cells. These compounds offer potential therapeutic benefits in managing diseases characterized by excessive MMP activity, such as periapical lesions and periodontal disease. This review highlights the therapeutic potential of MMP inhibitors in dentistry, specifically focusing on the promising roles of natural and synthetic MMP inhibitors in protecting ECM integrity.

Buonocore Memorial Lecture 2023: Changing Operative Mindsets with Universal Adhesives and Cements

Adhesive dentistry has undergone significant advancements since its inception, marked by continuous improvements in material performance and adaptability to various dental and restorative substrates. Initially, the anatomical differences between enamel and dentin made adhesive approaches challenging. Early systems were often complex and operator dependent, leading to the development of multistep protocols. However, advancements have led to the creation of more user-friendly self-etch systems and the emergence of universal adhesives (UAs). These UAs can be applied with equal effectiveness to different substrates, including enamel and dentin, simplifying the clinical workflow and enhancing reliability. The concept of universality has recently been extended to other dental materials, most notably universal resin cements. These cements offer a versatile approach as they are capable of both adhesive and self-adhesive bonding, thereby accommodating a wide range of restorative scenarios. The advent of these materials represents a significant advance toward simplifying procedures, reducing technique sensitivity and the likelihood of operator error, and achieving consistently high quality restorations. Current research focuses on further refining these universal materials to enhance their performance, making them a cornerstone of modern adhesive dentistry.

Mineralization promotion and protection effect of carboxymethyl chitosan biomodification in biomimetic mineralization

Biomimetic mineralization emphasizes reversing the process of dental caries through bio-inspired strategies, in which mineralization promotion and collagen protection are equally important. In this study, carboxymethyl chitosan (CMC) was deemed as an analog of glycosaminoglycan for biomimetic modification of collagen, both of the mineralization facilitation and collagen protection effect were evaluated. Experiments were carried out simultaneously on two-dimensional monolayer reconstituted collagen model, three-dimensional reconstituted collagen model and demineralized dentin model. In three models, CMC was successfully cross-linked onto collagen utilizing biocompatible 1-Ethyl-3(3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxy sulfosuccinimide sodium salt to achieve biomodification. Results showed that CMC biomodification increased collagen's hydrophilicity, calcium absorption capacity and thermal degradation resistance. In demineralized dentin model, the activity of endogenous matrix metalloproteinases was significantly inhibited by CMC biomodification. Furthermore, CMC biomodification significantly improved cross-linking and intrafibrillar mineralization of collagen, especially in the two-dimensional monolayer reconstituted collagen model. This study provided a biomimetic mineralization strategy with comprehensive consideration of collagen protection, and enriched the application of chitosan-based materials in dentistry.

The inhibitory effects of various ions released from S-PRG fillers on dentin protease activity

This study investigates the effect of ions released from S-PRG fillers on host-derived enzymatic degradation of dentin collagen matrices. Dentin beams (n=80) were demineralized and distributed to eight groups following baseline dry mass and total MMP activity assessments. Each group treated with boron, fluoride, sodium, silicone, strontium, aluminium, or S-PRG eluate solutions for 5 min. Untreated beams served as control. After pre-treatment, MMP activity was reassessed, beams were incubated in complete medium for 1 week, dry mass was reassessed. Incubation media were analyzed for MMP and cathepsin-K-mediated degradation fragments. Data were analyzed with ANOVA and Tukey's test. All pretreatment groups showed significant reduction in total MMP activity (p<0.05) that was sustainable after incubation in all groups except for boron and silicone groups (p<0.05). Cathepsin-K activity did not differ between control or treatment groups. The results indicated that ions released from S-PRG fillers have the potential to partly inhibit MMP-mediated endogenous enzymatic activity.

Matrix Metalloproteinases in Dental and Periodontal Tissues and Their Current Inhibitors: Developmental, Degradational and Pathological Aspects

Objectives: This review article aims to describe some of the roles of Matrix metalloproteinases (MMPs) in enamel, dentine, dental caries, hybrid layer degradation, pulp and periodontal tissues, throwing light on their current inhibitors. The article addresses the potential of MMPs to serve as biomarkers with diagnostic and therapeutic value. Design: The sections of this review discuss MMPs’ involvement in developmental, remodeling, degradational and turnover aspects of dental and periodontal tissues as well as their signals in the pathogenesis, progress of different lesions and wound healing of these tissues. The literature was searched for original research articles, review articles and theses. The literature search was conducted in PubMed and MEDLINE for articles published in the last 20 years. Results: 119 published papers, two textbooks and two doctoral theses were selected for preparing the current review. Conclusions: MMPs are significant proteases, of evident contribution in dental and periapical tissue development, health and disease processes, with promising potential for use as diagnostic and prognostic disease biomarkers. Continuing understanding of their role in pathogenesis and progress of different dental, periapical and periodontal lesions, as well as in dentine-pulp wound healing could be a keystone to future diagnostic and therapeutic regimens.