Role of proteoglycans on the biochemical and biomechanical properties of dentin organic matrix

Abstract

Objective Proteoglycans (PGs) are multifunctional biomacromolecules of the extracellular matrix of collagen-based tissues. In teeth, besides a pivotal regulatory role on dentin biomineralization, PGs provide mechanical support to the mineralized tissue and compressive strength to the biosystem. This study assessed enzymatic protocols for selective PGs removal from demineralized dentin to determine the roles of these biomacromolecules in the bulk mechanical properties and biostability of type I collagen. Methods Selective removal of glycosaminoglycans chains (GAGs) and PGs from demineralized dentin was carried out by enzymatic digestion protocols using chondroitinase ABC (c-ABC) and trypsin (Try). A comprehensive study design included assessment of dentin matrix mass loss, biodegradability of the PGs/GAGs-depleted dentin matrix, ultimate tensile strength (UTS) and energy to fracture tests. Quantitative data was statistically analyzed by two-way and one-way ANOVA followed by the appropriate post hoc tests (α = 0.05). Results Transmission electron microscopy images show effective GAGs removal by c-ABC and Try and both enzymatic methods released statistically similar amounts of GAGs from the demineralized dentin. Try digestion resulted in about 25% dentin matrix mass loss and increased susceptibility to collagenolytic digestion when compared to c-ABC (p = 0.0224) and control (p = 0.0901). Moreover, PGs digestion by Try decreased the tensile strengths of dentin. Statistically lower energy to fracture was observed in c-ABC-treated dentin matrix. Conclusions GAGs plays a pivotal role on tissue mechanics and anisotropy, while the core protein of PGs have a protective role on matrix biostability.

Reconstruction of a Demineralized Dentin Matrix via Rapid Deposition of CaF2 Nanoparticles In Situ Promotes Dentin Bonding

“…Additionally, 13 C and 19 F magic angle spinning (MAS) solidstate nuclear magnetic resonance (ssNMR) was employed to investigate the interactions between the CaF 2 nanoparticles and the DD matrix (Figure 3C). The 13 C spectra show a fingerprint of the typical dentin matrix.…”

“…The high hydration capability of these polar groups allows the NCPs to form a hydrogel-like structure on dentin collagen fibers. This negatively charged hydrogel-like interfacial microenvironment of the DD matrix is a naturally mineralization-induced environment, which regulates the mineralization process in dentinogenesis. , During wet bonding, the high hydration of the interfacial environment is vitally important for the DD matrix to retain a fluffy state, providing spaces for infiltration of the adhesives . However, the hydrogel-like interfacial environment also acts as “molecular sieves” to impede the infiltration of the adhesive monomers, especially the critical hydrophobic macromolecules, such as bisphenol A-glycidyl methacrylate (Bis-GMA), triethylene glycol dimethacrylate (TEGDMA), etc.…”

Otojen Di̇ş Kemi̇k Grefti̇ni̇n Bi̇yoloji̇k Özelli̇kleri̇ Ve Kli̇ni̇k Kullanimi

“…13 Bu matriks, HA bağlayıcı proteinler ve matriks içindeki endojen büyüme faktörlerinin salınması için önemli olan nano boyuttaki dentin tübüllerini içerir. [18][19][20] Yapısal proteinler olarak ekstrasellüler matriks molekülleri, dentin oluşumuna ve mineralleşmesine katılır. 13 Uyarıcı veya inhibitör olarak görev yapabilirler.…”

“…19 Bu nedenle, tübüler dentin olarak da adlandırılmaktadır ve içerisinde eş zamanlı olarak gelişen ancak yapısal ve içerik olarak farklılık gösteren iki farklı tübüller yapı bulunmaktadır: intertübüler dentin ve peritübüler dentin. 20 Peritübüler dentin, tübüler lümenin çevresinde gözlenen mineralize bir yapıdır. Farklı olarak, intertübüler dentin, dentin oluşumunda rol alan organik içeriği (tip 1 kollajen) ile tübüler dentinin büyük bir kısmını oluşturur.…”

Effect of bromelain and trypsin on microleakage of etch-and-rinse adhesive systems

“…It seems that proteoglycans play a pivotal role in the dentin extracellular matrix, due to their inherent ability in bonding to water, and have a key role in the size of interfibrillar collagen spaces [13,14]. The interfibrillar regions in acid-etched dentin have proteoglycans.…”