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Use of poly (amidoamine) dendrimer for dentinal tubule occlusion: a preliminary study.

Wang T, Yang S, Wang L, Feng H - PLoS ONE (2015)

Bottom Line: The in situ mineralization within dentinal tubules is a promising treatment for dentin hypersensitivity as it induces the formation of mineral on the sensitive regions and occludes the dentinal tubules.These results showed that G3.0 PAMAM dendrimers coated on dentin surface and infiltrated in dentinal tubules could induce hydroxyapatite formation and resulted in effective dentinal tubule occlusion.This could lead to the development of a new therapeutic technique for the treatment of dentin hypersensitivity.

View Article: PubMed Central - PubMed

Affiliation: Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing, China.

ABSTRACT
The occlusion of dentinal tubules is an effective method to alleviate the symptoms caused by dentin hypersensitivity, a significant health problem in dentistry and daily life. The in situ mineralization within dentinal tubules is a promising treatment for dentin hypersensitivity as it induces the formation of mineral on the sensitive regions and occludes the dentinal tubules. This study was carried out to evaluate the in vitro effect of a whole generation poly(amidoamine) (PAMAM) dendrimer (G3.0) on dentinal tubule occlusion by inducing mineralization within dentinal tubules. Dentin discs were treated with PAMAM dendrimers using two methods, followed by the in vitro characterization using Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM) and Energy-Dispersive X-ray Spectroscopy (EDS). These results showed that G3.0 PAMAM dendrimers coated on dentin surface and infiltrated in dentinal tubules could induce hydroxyapatite formation and resulted in effective dentinal tubule occlusion. Moreover, crosslinked PAMAM dendrimers could induce the remineralization of demineralized dentin and thus had the potential in dentinal tubule occlusion. In this in vitro study, dentinal tubules occlusion could be achieved by using PAMAM dendrimers. This could lead to the development of a new therapeutic technique for the treatment of dentin hypersensitivity.

No MeSH data available.


Related in: MedlinePlus

Mechanism of glutaraldehyde crosslinking.(A) Chemical reaction equation. (B) Schema chart that reveals the process of PAMAM dendrimers crosslinked to demineralized dentinal collagen by using glutaraldehyde.
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pone.0124735.g006: Mechanism of glutaraldehyde crosslinking.(A) Chemical reaction equation. (B) Schema chart that reveals the process of PAMAM dendrimers crosslinked to demineralized dentinal collagen by using glutaraldehyde.

Mentions: To date, two main strategies were carried out to remineralize demineralized dentin. One strategy depended on the heterogeneous nucleation which was induced by seed crystallites arising from the partially demineralization. Although employed in many aspects including the remineralization of carious dentin, such a traditional ion-based strategy cannot be used in locations where seed crystallites are absent, for example the completely demineralized dentin created by etch-and-rinse adhesive systems or the superficial part of a caries-affected dentin lesion[44–46]. The other kind of remineralization strategy based on the bottom-up mechanism referring to material assembly from nanoscopic scale, such as molecules and atoms, to form larger structures[47]. Biomineralizaiton, especially the mineralization of human dentin, is a perfect example representing the bottom-up approach[48,49]. Dentin is a highly complex composite that is composed of 50 weight percent (wt%) inorganic mineral, 40 wt% extracellular matrix (ECM) and 10 wt% aqueous fluids[50]. Ninety weight percent of ECM is type I collagen which provides the three-dimensional structural framework for dentin biomineralization[51,52]. In addition to type I collagen, the ECM component contains acidic noncollagenous proteins (NCPs), including dentin matrix protein 1 (DMP-1), dentin sialaprotein (DSP) and dentin phosphoprotein (DPP)[53]. These NCPs are rich in acidic amino acids, such as glutamic acid and aspartic acid, which can attach to collagen fibrils, nucleate the formation of HAP, and regulate the dentin biomineralization process. Under regulation by NCPs, collagen fibrils are embedded with HAP platelets that are preferentially [0 0 1] aligned parallel to the long axis of the collagen fibrils, along the microfibrillar spaces; this forms the most fundamental level of the dentin structure[54]. In this study, PAMAM dendrimers possessing the ability to induce mineralization has been employed as a mimetic analog of NCPs. The occlusion of dentinal tubules was expected to be achieved through the further crystal growth after PAMAM induced nucleation. Different from the applications of other mimetic analogs like polyacrylic acid (PAA) and polyaspartic acid (pAsp) via electrostatic interaction, PAMAM dendrimers were crosslinked with demineralized dentin collagen using glutaraldehyde. Glutaraldehyde is the main ingredient in Gluma, which is a commonly used desensitizing agent. In this study, the crosslinking ability of glutaraldehyde was employed. Free primary amine groups (–NH2) of G3.0 PAMAM dendrimers and collagen fibrils can easily react with the aldehyde groups (-C = O) of glutaraldehyde to form Schiff’s base and the two kinds of molecules will be linked with covalent bonding[55] which can also be formed between PAMAM dendrimer molecules (Fig 6) and is better than easily interfered electrostatic interaction employed in the applications of other kinds of biomimetic analogs of NCPs (e.g. polyvinylphosphonic acid, PVPA)[56]. As shown in Fig 4C and 4D, demineralized collagen fibrils exhibited a “corn-on-the-cob” appearance after they were crosslinked with G3.0 PAMAM dendrimers using glutaraldehyde. With PAMAM dendrimers immobilized on the surface, a whole demineralized collagen fibril would turn into a nucleator and induce crystal formation in simulated body fluid. After crystal nucleation and PAMAM dendrimers crosslinked collagen fibrils were embedded with crystal nucleus, the surface of demineralized dentin and dentinal tubules would be covered with minerals which were induced through further heterogeneous nucleation, as is shown in SEM images. Although occlusion of dentinal tubules was not observed directly, remineralization of demineralized induced by PAMAM dendrimers immobilized on collagen fibrils is considered to have the potential to occlude patent dentinal tubules through the outward growth of the previously formed crystals. On the other hand, with glutaraldehyde, a network crosslinking structure can be created intra- and intermolecularly within collagen fibrils, providing the fibrillar resistance against enzymatic degradation as well as greater tensile properties, which is an important application in restorative dentistry[57].


Use of poly (amidoamine) dendrimer for dentinal tubule occlusion: a preliminary study.

Wang T, Yang S, Wang L, Feng H - PLoS ONE (2015)

Mechanism of glutaraldehyde crosslinking.(A) Chemical reaction equation. (B) Schema chart that reveals the process of PAMAM dendrimers crosslinked to demineralized dentinal collagen by using glutaraldehyde.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4401684&req=5

pone.0124735.g006: Mechanism of glutaraldehyde crosslinking.(A) Chemical reaction equation. (B) Schema chart that reveals the process of PAMAM dendrimers crosslinked to demineralized dentinal collagen by using glutaraldehyde.
Mentions: To date, two main strategies were carried out to remineralize demineralized dentin. One strategy depended on the heterogeneous nucleation which was induced by seed crystallites arising from the partially demineralization. Although employed in many aspects including the remineralization of carious dentin, such a traditional ion-based strategy cannot be used in locations where seed crystallites are absent, for example the completely demineralized dentin created by etch-and-rinse adhesive systems or the superficial part of a caries-affected dentin lesion[44–46]. The other kind of remineralization strategy based on the bottom-up mechanism referring to material assembly from nanoscopic scale, such as molecules and atoms, to form larger structures[47]. Biomineralizaiton, especially the mineralization of human dentin, is a perfect example representing the bottom-up approach[48,49]. Dentin is a highly complex composite that is composed of 50 weight percent (wt%) inorganic mineral, 40 wt% extracellular matrix (ECM) and 10 wt% aqueous fluids[50]. Ninety weight percent of ECM is type I collagen which provides the three-dimensional structural framework for dentin biomineralization[51,52]. In addition to type I collagen, the ECM component contains acidic noncollagenous proteins (NCPs), including dentin matrix protein 1 (DMP-1), dentin sialaprotein (DSP) and dentin phosphoprotein (DPP)[53]. These NCPs are rich in acidic amino acids, such as glutamic acid and aspartic acid, which can attach to collagen fibrils, nucleate the formation of HAP, and regulate the dentin biomineralization process. Under regulation by NCPs, collagen fibrils are embedded with HAP platelets that are preferentially [0 0 1] aligned parallel to the long axis of the collagen fibrils, along the microfibrillar spaces; this forms the most fundamental level of the dentin structure[54]. In this study, PAMAM dendrimers possessing the ability to induce mineralization has been employed as a mimetic analog of NCPs. The occlusion of dentinal tubules was expected to be achieved through the further crystal growth after PAMAM induced nucleation. Different from the applications of other mimetic analogs like polyacrylic acid (PAA) and polyaspartic acid (pAsp) via electrostatic interaction, PAMAM dendrimers were crosslinked with demineralized dentin collagen using glutaraldehyde. Glutaraldehyde is the main ingredient in Gluma, which is a commonly used desensitizing agent. In this study, the crosslinking ability of glutaraldehyde was employed. Free primary amine groups (–NH2) of G3.0 PAMAM dendrimers and collagen fibrils can easily react with the aldehyde groups (-C = O) of glutaraldehyde to form Schiff’s base and the two kinds of molecules will be linked with covalent bonding[55] which can also be formed between PAMAM dendrimer molecules (Fig 6) and is better than easily interfered electrostatic interaction employed in the applications of other kinds of biomimetic analogs of NCPs (e.g. polyvinylphosphonic acid, PVPA)[56]. As shown in Fig 4C and 4D, demineralized collagen fibrils exhibited a “corn-on-the-cob” appearance after they were crosslinked with G3.0 PAMAM dendrimers using glutaraldehyde. With PAMAM dendrimers immobilized on the surface, a whole demineralized collagen fibril would turn into a nucleator and induce crystal formation in simulated body fluid. After crystal nucleation and PAMAM dendrimers crosslinked collagen fibrils were embedded with crystal nucleus, the surface of demineralized dentin and dentinal tubules would be covered with minerals which were induced through further heterogeneous nucleation, as is shown in SEM images. Although occlusion of dentinal tubules was not observed directly, remineralization of demineralized induced by PAMAM dendrimers immobilized on collagen fibrils is considered to have the potential to occlude patent dentinal tubules through the outward growth of the previously formed crystals. On the other hand, with glutaraldehyde, a network crosslinking structure can be created intra- and intermolecularly within collagen fibrils, providing the fibrillar resistance against enzymatic degradation as well as greater tensile properties, which is an important application in restorative dentistry[57].

Bottom Line: The in situ mineralization within dentinal tubules is a promising treatment for dentin hypersensitivity as it induces the formation of mineral on the sensitive regions and occludes the dentinal tubules.These results showed that G3.0 PAMAM dendrimers coated on dentin surface and infiltrated in dentinal tubules could induce hydroxyapatite formation and resulted in effective dentinal tubule occlusion.This could lead to the development of a new therapeutic technique for the treatment of dentin hypersensitivity.

View Article: PubMed Central - PubMed

Affiliation: Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing, China.

ABSTRACT
The occlusion of dentinal tubules is an effective method to alleviate the symptoms caused by dentin hypersensitivity, a significant health problem in dentistry and daily life. The in situ mineralization within dentinal tubules is a promising treatment for dentin hypersensitivity as it induces the formation of mineral on the sensitive regions and occludes the dentinal tubules. This study was carried out to evaluate the in vitro effect of a whole generation poly(amidoamine) (PAMAM) dendrimer (G3.0) on dentinal tubule occlusion by inducing mineralization within dentinal tubules. Dentin discs were treated with PAMAM dendrimers using two methods, followed by the in vitro characterization using Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM) and Energy-Dispersive X-ray Spectroscopy (EDS). These results showed that G3.0 PAMAM dendrimers coated on dentin surface and infiltrated in dentinal tubules could induce hydroxyapatite formation and resulted in effective dentinal tubule occlusion. Moreover, crosslinked PAMAM dendrimers could induce the remineralization of demineralized dentin and thus had the potential in dentinal tubule occlusion. In this in vitro study, dentinal tubules occlusion could be achieved by using PAMAM dendrimers. This could lead to the development of a new therapeutic technique for the treatment of dentin hypersensitivity.

No MeSH data available.


Related in: MedlinePlus