The Use of Montmorillonite Clays as Reinforcing Fillers for Dental Adhesives

Menezes, Lívia Rodrigues de; Silva, Emerson Oliveira da

doi:10.1590/1980-5373-mr-2015-0375

Cited by 29 publications

(16 citation statements)

References 35 publications

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“…The resulting dental adhesive reduces the weakening of tooth structure. However, the highest concentration of 1.5% produced agglomerated clay and no significant performance enhancement [35].…”

Section: Resistance To Tooth Decaymentioning

confidence: 89%

Montmorillonite: An Introduction to Properties and Utilization

Uddin¹

2018

Current Topics in the Utilization of Clay in Industrial and Medical Applications

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Clay mineral is an important material available in nature. With an increasing understanding of clay structure, montmorillonite is realized viable for an enhanced performance in a variety of materials and products in the areas of catalysis, food additive, antibacterial function, polymer, sorbent, etc. Significant development in the use and application of montmorillonite is seen in recent time. This chapter provides an overview of montmorillonite, structure, and properties and particularly discusses its recent utilization in important materials. Montmorillonite is introduced in terms of its natural sources, chemical structure, physical and chemical properties, and functional utilization. The important physical and chemical properties are summarized as particle and layered structure, molecular structure and cation exchange effect, barrier property, and water sorption. This is followed by the important functional utilizations of montmorillonite based on the effects of its chemical structure. The important functional utilization of montmorillonite includes food additive for health and stamina, for antibacterial activity against tooth and gum decay, as sorbent for nonionic, anionic, and cationic dyes, and the use as catalyst in organic synthesis. The environment concerns, to date, do not indicate the adversity for particles used as additive. Studies will be useful which are clearly based on any montmorillonite structure to describe environmental effects.A common characteristic of clay mineral is a fine-grained natural structure in a sheet-like geometry. The sheet-structured hydrous silicates are generally called phyllosilicates [3]. The natural clay particle is smaller than 0.004 mm in diameter that may range from 0.002 to 0.001 mm for quartz, mica, feldspar, iron, and aluminum oxides [4]. Colloidal clay particles are finer and found in layered silicates (<0.001 mm in diameter).Clay minerals may be grouped in four types, shown in Table 1. The group members vary mainly in the layered structure. These include the kaolinite group, the smectite group (montmorillonite group), the illite group, and the chlorite group [5].The kaolinite group has three members including kaolinite, dickite, and nacrite; the formula for kaolinite group is Al 2 Si 2 O 5 (OH) 4 .The illite group is represented by mineral illite, the only common clay type. The general formula for illite is (K, H)Al 2 (Si, Al) 4 O 10 (OH) 2 ⋅ XH 2 O. It is an important rock-forming mineral and main component of shales. The structure of this group is similar to the montmorillonite group with silicate layers sandwiching an aluminum oxide/hydroxide layer in the same stacking sequence.The chlorite group is relatively large. This group is not necessarily considered as part of clays; therefore, it is placed as a separate group in phyllosilicate. The members in chlorite group are mesite, chamosite, cookeite, and daphnite with varying formulas and structures. There is no general formula.The variety of clay minerals is based on the arrangement of tetrahedral and octahedral s...

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Section: Resistance To Tooth Decaymentioning

confidence: 89%

Montmorillonite: An Introduction to Properties and Utilization

Uddin¹

2018

Current Topics in the Utilization of Clay in Industrial and Medical Applications

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“…Accordingly, the maximum strength of the composite membrane increased with increasing C 3 S concentration, while the strain at break decreased when the C 3 S content is higher. The increased concentration of C 3 S might act as reinforcing filler for the increased bonding conditions of PLLA/C 3 S composite [28], which leads to its higher tensile strength and stronger resistance to the shape changes. From which the durability of the composite membrane, which shows the ability of the membrane specimen to resist changes of shape without cracking was decreased with the increasing concentration of C 3 S as well [29], which is in agreement with the general trend observed in Figure 3(a).…”

Section: Tensile Propertiesmentioning

confidence: 99%

Fabrication of PLLA/C3S Composite Membrane for the Prevention of Bone Cement Leakage

et al. 2019

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Kyphoplasty is an important treatment for stabilizing spine fractures due to osteoporosis. However, leakage of polymethyl-methacrylate (PMMA) bone cement during this procedure into the spinal canal has been reported to cause many adverse effects. In this study, we prepared an implantable membrane to serve as a barrier that avoids PMMA cement leakage during kyphoplasty procedures through a hybrid composite made of poly-l-lactic acid (PLLA) and tricalcium silicate (C 3 S), with the addition of C 3 S into PLLA matrix, showing enhanced mechanical and anti-degradation properties while keeping good cytocompatibility when compared to PLLA alone and most importantly, when this material design was applied under standardized PMMA cement injection conditions, no posterior wall leakage was observed after the kyphoplasty procedure in pig lumbar vertebral bone models. Testing results assess its effectiveness for clinical practice.2 of 17 the created cavity after balloon inflation during the kyphoplasty procedure [10]. Following which the balloon is re-inserted and inflated, creating a cement shell or a cement membrane around the inner walls of the created cavity, and another batch of cement was mixed and injected into the remaining cavity thereafter with limited cement leakage possibility from initial cement setting. Although this double cement application with PMMA as the cement anti-leakage shell or membrane has demonstrated its efficacy in clinical trial during the kyphoplasty procedure [11], the long term complications might be devastating due to PMMA presence on the bone cement surface [9], which makes the development of a new material design for anti-leakage membrane necessary. For example, Tetsushi Taguchi et al. had fabricated the reactive poly(vinyl alcohol) (PVA) membrane for the prevention of bone cement leakage with good potential for implantable balloon kyphoplasty, but further investigations on its clinical efficiency are still in progress [12].On the other hand, polymeric membranes fabricated from a single material more often have limited biological performance compared to the use of hybrid biomaterials composed of biodegradable synthetic polymers and inorganic materials, with the hybrid biomaterials fitting better to bone tissue engineering applications due to their similar compositions to natural bones [13,14]. For example, biodegradable polymers such as poly(L-lactic acid) (PLLA) (L-lactic acid isomer of polylactic acid (PLA), an aliphatic thermoplastic polyester obtained by polymerizing lactide monomers) have been used for scaffold design doped with dicalcium silicate (C 2 S) nanoparticles as an ideal candidate for novel bone graft substitutes with enhanced mechanical and biodegradable properties, and biointeractive nature [15,16]. Scaffolds fabricated from (PLLA)/dicalcium phosphate dihydrate (DCPD) composite by indirect casting had also shown to effectively improve the mechanical strength and biocompatibility for the repair of bone defects when compared to the scaffold from neat PLLA [17]. From which the h...

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“…The HEMA-P 40% /SiO 2 -POOH 0.1% showed significantly higher bond strengths (≈50%) than the correspondent unfilled 1-SEA HEMA-P 40% . Previous studies have already been proven that the addition of an optimum amount of filler into adhesives increases the mechanical properties and bond strength [18,19,25]. The increase in these properties is due an increment of the elastic modulus of the adhesive layer between dentin and restoration.…”

Section: Discussionmentioning

confidence: 98%