Effect Of Amorphous Calcium Phosphate Research Articles

Toward the understanding of poly (Acrylic Acid) on amorphous calcium phosphate mediated collagen intrafibrillar Mineralization: Surface adsorption versus bulk incorporation

Poly (acrylic acid) (PAA), as a noncollagenous proteins (NCPs) mimic, is considered to play a crucial role in biomimetic collagen mineralization. However, its regulation mechanism in collagen mineralization is yet not fully elucidated. Here, we especially have focused on what is the effect of amorphous calcium phosphate (ACP) associated with surface adsorption or bulk incorporation of PAA on collagen intrafibrillar mineralization. We found that no matter PAA is adsorbed on or incorporated into ACP, it facilitates intrafibrillar mineralization in a concentration-dependent manner. But, importantly, in the presence of 60 μg/mL PAA, almost fully intrafibrillar mineralization can be achieved when PAA is adsorbed on ACP surface (ACPS), which can just obtain partial intrafibrillar mineralization when PAA is incorporated into ACP (ACPB). The reason lies in the high electrostatic interaction of ACPS with fibrils and creating a local supersaturation around collagen-I fibrils when PAA is adsorbed on the ACP surface. Conversely, ACP nanoparticles were almost not charged when PAA is incorporated into ACP. This finding demonstrates that the spatial distribution of additives with ACP nanoparticles is crucial for collagen intrafibrillar mineralization in vitro and may provide new insights for the regulation and design of biomimetic materials.

The Remineralizing Effect of Incorporating Ca-Phosphate and Ca-Fluoride Nanoparticles into the Self-Etch Adhesives Used in Restoring Class I Cavities

This study was carried out to investigate the remineralizing effect of amorphous calcium phosphate (ACP) and calcium fluoride (CaF2) nanoparticles incorporated in two-step self etch- adhesives (in vivo). Materials and Methods: The nanoparticles were incorporated into the bond of ClearfilTM SE Bond at a mass fraction of 10%. A total of ten patients in the age range of 17-30 years old, having at least 3 carious lower molars, were enrolled in this study (split mouth design). Class I cavity preparation was performed, leaving the caries affected dentine at the pulpal floor. The 30 molars were divided into 3 groups (n=10) according to the type of adhesive used (A); namely: self-etch adhesive, Clearfil SE Bond (Control)(A1), Clear Fill SE Bond incorporated with ACP NPs (A2) and Clearfil SE Bond incorporated with CaF2 NPs (A3). After restoration placement, each tooth was radiographically evaluated at baseline (I0), after 1 month (I1) and after 3 months (I2) to assess the remineralizing effect of the adhesive systems used. Results: The adhesive containing ACP nanoparticles induced the highest remineralization potential during all the study intervals, followed by the adhesive containing (CaF2) nanoparticles. Conclusion: nanoparticles are capable of remineralizing the caries affected dentin when incorporated into two-step self etch adhesive

The Remineralizing Effect of Incorporating Ca-Phosphate and Ca-Fluoride Nanoparticles into the Self-Etch Adhesives Used in Restoring Class I Cavities

This study was carried out to investigate the remineralizing effect of amorphous calcium phosphate (ACP) and calcium fluoride (CaF2) nanoparticles incorporated in two-step self etch- adhesives (in vivo). Materials and Methods: The nanoparticles were incorporated into the bond of ClearfilTM SE Bond at a mass fraction of 10%. A total of ten patients in the age range of 17-30 years old, having at least 3 carious lower molars, were enrolled in this study (split mouth design). Class I cavity preparation was performed, leaving the caries affected dentine at the pulpal floor. The 30 molars were divided into 3 groups (n=10) according to the type of adhesive used (A); namely: self-etch adhesive, Clearfil SE Bond (Control)(A1), Clear Fill SE Bond incorporated with ACP NPs (A2) and Clearfil SE Bond incorporated with CaF2 NPs (A3). After restoration placement, each tooth was radiographically evaluated at baseline (I0), after 1 month (I1) and after 3 months (I2) to assess the remineralizing effect of the adhesive systems used. Results: The adhesive containing ACP nanoparticles induced the highest remineralization potential during all the study intervals, followed by the adhesive containing (CaF2) nanoparticles. Conclusion: nanoparticles are capable of remineralizing the caries affected dentin when incorporated into two-step self etch adhesive

An In Vitro Study on the Effect of Amorphous Calcium Phosphate and Fluoride Solutions on Color Improvement of White Spot Lesions.

The ability of remineralizing agents to improve the color of white spot lesions (WSL) is an important aspect that should be investigated. The aim of this study was to evaluate the effects of 0.05% amorphous calcium phosphate (ACP), 0.5% ACP, and 0.05% fluoride solutions, as well as artificial saliva on the color improvement of white spot lesions (WSLs). In this in vitro study, 50 human premolar teeth were randomly classified into five groups. At baseline, all the samples were assessed by using a colorimeter (E0). Then, white spot lesions were induced on the surface of the teeth by means of a pH-cycling model, and the colorimeter was used again (E1). Afterwards, samples of the 1st and 2nd groups were kept in 0.05% ACP and 0.5% ACP solutions for 1 min/day, respectively. The 3rd group specimens were placed in 0.05% fluoride solution for 1 min/day. The other two groups were kept in artificial saliva and distilled in water separately. All the samples were assessed by the colorimeter for a third time (E2). We found no significant difference between the groups in ∆E1. There was also no significant difference among 0.05% ACP solution, 0.5% ACP solution, 0.05% fluoride solution, and artificial saliva considering ∆E2. However, a significant difference was noted between the above-mentioned solutions and distilled water in ∆E2. With respect to ∆E3, there were considerable differences between ACP solution and artificial saliva. The same results were obtained for the difference between fluoride solution and artificial saliva. However, no significant difference was found among 0.05% ACP, 0.5% ACP, and 0.05% fluoride solutions in terms of ∆E3. In Conclusion, ACP is as effective as fluoride in the color improvement of WSLs and the recommended treatment for this purpose is daily use of 0.05% ACP, 0.5% ACP or 0.05% fluoride solutions.

Ability of Pit and Fissure Sealant-containing Amorphous Calcium Phosphate to inhibit Enamel Demineralization.

ABSTRACTAim: To evaluate the effect of amorphous calcium phosphate (ACP)-containing pit and fissure sealant on inhibition of enamel demineralization in vitro.Materials and methods: Enamel specimens (n = 75) were prepared using freshly extracted noncarious human third molars. Box-shaped cavities (8 × 2 × 2 mm) on the buccal or lingual surfaces were prepared and restored with resin-based sealant (Concise™), ACP-containing sealant (Aegis®) or fluoride-containing sealant (Conseal-F™). The samples were acid challenged in a demineralizing solution of 50 mmol/l lactic acid at pH 5.0 for 4 days. The change in enamel microhardness (ASuH) was calculated. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey’s post hoc test.Results: The mean SuH0 (±SD) (in Vicker’s unit) prior to the acid challenge was: Concise™ (318.83 ± 33.86), Aegis® (331.03 ± 21.52), Conseal-F™ (310.12 ± 34.31). Following the acid challenge, the values dropped in all groups and ASuH (±SD) values were 269.17 ± 47.49, 151.39 ± 23.96 and 175.79 ± 32.39 respectively.Conclusion: The ACP-containing pit and fissure sealant has the potential to inhibit enamel demineralization.How to cite this article: Zawaideh FI, Owais AI, Kawaja W. Ability of pit and fissure sealant-containing amorphous calcium phosphate to inhibit enamel demineralization. Int J Clin Pediatr Dent 2016;9(1):10-14.

The effect of amorphous calcium phosphate on protein protection against thermal denaturation.

The hybrid nanoparticles of amorphous calcium phosphate (ACP)-catalase (CAT) developed by in situ biomineralization can create a stable semi-aqueous nanoscale environment for entrapped proteins against thermal denaturation. This finding indicates the importance of an amorphous mineral phase in the preservation of organic macromolecules.

Comparative Study of Amorphous Calcium Phosphate-containing Orthodontic Composite and Conventional Orthodontic Adhesive on Enamel Demineralization around Orthodontic Brackets – An in vivo Study

Introduction: One of the most difficult problems in orthodontic treatment with fixed appliances is enamel demineralization around the brackets. This iatrogenically caused white spot lesions leads to poor esthetics; and in severe cases it may need restorative treatment.
 Objective: To evaluate in vivo effect of Amorphous Calcium Phosphate (ACP)-containing orthodontic composite on enamel demineralization around orthodontic brackets, and to compare it with the conventional resin based orthodontic composite.
 Materials & Method: 20 orthodontic patients planned for four first premolars extraction were selected for the study. All first premolars were bonded with Aegis Ortho, an ACP-containing orthodontic composite (experimental group), and Transbond XT, a resin-based orthodontic composite (control group). After 45 days teeth were extracted, sectioned for the microhardness group and evaluated by superficial-microhardness analysis and stereomicroscopic study. Unpaired t-test and analysis of variance (ANOVA) test was performed.
 Result: The ANOVA showed statistically significant differences for position, material, depth, and their interactions (p <0.001). The multiple comparison test showed that the ACP-containing orthodontic composite was significantly more efficient than the conventional composite, reducing enamel demineralization in almost all evaluations (p <0.001). The stereomicroscopic examinations showed a lesser extent of demineralization around orthodontic brackets for the ACP-containing orthodontic composite group.
 Conclusion: ACP-containing orthodontic composite for bonding orthodontic brackets successfully inhibited demineralization, which was localized to the area around the brackets.

Effect of amorphous calcium phosphate and silver nanocomposites on dental plaque microcosm biofilms

A dental composite containing amorphous calcium phosphate nanoparticles (NACP) was developed that released calcium (Ca) and phosphate (PO(4)) ions and possessed acid-neutralization capability. There has been little study on incorporation of antibacterial agents into calcium phosphate composites. The objective of this study was to investigate the effect of silver nanoparticle (NAg) mass fraction in NACP nanocomposite on mechanical properties and dental plaque microcosm biofilm for the first time. NACP nanoparticles of 116 nm were synthesized via a spray-drying technique. NAg nanoparticles were synthesized using Ag 2-ethylhexanoate and 2-(tert-butylamino)ethyl methacrylate, yielding NAg of particle size of 2.7 nm that were well-dispersed in the resin. Five NACP nanocomposites were fabricated with NAg mass fractions of 0, 0.028, 0.042, 0.088, and 0.175%, respectively. Mechanical properties of NACP nanocomposites containing 0-0.042% of NAg matched those of a commercial composite without antibacterial activity. Live/dead assay of dental plaque microcosm biofilms showed complete coverage with live bacteria on commercial composite. However, there were increasingly more dead bacteria with higher NAg content in the NACP nanocomposite. Colony-forming unit (CFU) counts for total microorganisms, total streptococci, and mutans streptococci for NACP nanocomposite with 0.042% NAg were about 1/4 those of commercial composite. Lactic acid production on NACP nanocomposite with 0.042% NAg was 1/3 that on commercial composite. In conclusion, novel NACP-NAg nanocomposites were developed which possessed good mechanical properties and potent antibacterial properties, with substantially reduced biofilm viability and lactic acid production. Hence, the NACP-NAg nanocomposites are promising for dental restorations with remineralizing and antibacterial capabilities.

Characterization of cytolytic neutrophil activation in vitro by amorphous hydrated calcium phosphate as a model of biomaterial inflammation

Calcium ions are utilized in biomolecular biomaterial design for osteomimetic scaffolds and as divalent cross-linking agents, typically for gelation of alginates, stabilisation of protein structure (e.g., fibrinogen) and enzyme activation (e.g., thrombin). Biological interactions with defined calcium phosphates (e.g., hydroxyapatite) are exploited for osteogenesis, although crystalline calcium phosphates (e.g., calcium pyrophosphate) stimulate inflammation. We found that the calcium concentration used in the manufacture of prototype dermal scaffolds made from fibrin/alginate composite was related to the inflammatory infiltration during in vivo integration. In investigating a cause for this inflammatory response, we have identified and characterized a cytolytic inflammatory effect of amorphous calcium phosphate (CaP) formed in physiological solutions, relevant to biomaterial biocompatibility. Isolated human neutrophils (Nφ) were incubated in phosphate-buffered saline with CaCl(2) ranging 2.5-20 mM total calcium. Nφ activation was assessed by morphology and integrin-β2 (CD18a) expression. Mediator release (Nφ-elastase, IL-8, and TNFα) was measured from both Nφ and whole blood cultures plus CaCl(2). CaP exposure increased CD18a expression over 1 h (maximal at 10 mM calcium/ phosphate) with concurrent phagocytosis, cytolysis, and Nφ-elastase release. CaCl(2) induced expression of IL-8 and TNFα in whole blood cultures. These results suggest that CaP formed from the resorption of calcium-containing biomaterials could induce inflammation and accelerate biomaterial degradation, driving further CaP release. This demonstrates a novel mechanism for biomaterial-induced inflammation. The in vitro system described could aid preclinical evaluation of novel biomaterial inflammatory potential.

Mechanical and histological evaluation of amorphous calcium phosphate and poorly crystallized hydroxyapatite coatings on titanium implants.

The effect of amorphous calcium phosphate (Ca/P) and poorly crystallized (60% crystalline) hydroxyapatite (HA) coatings on bone fixation to "smooth" and "rough" (Ti-6A1-4V powder sprayed) titanium-6Al-4V (Ti) implants was investigated. Implants were evaluated histologically, mechanically, and by scanning electron microscopy (SEM) after 4 and 12 weeks of implantation in a rabbit transcortical femoral model. Histological evaluation of amorphous vs. poorly crystallized HA coatings showed significant differences in bone apposition (for rough-coated implants only) and coating resorption (for smooth- and rough-coated implants) that were increased within cortical compared to cancellous bone. The poorly crystallized HA coatings showed most degradation and least bone apposition. Mechanical evaluation, however, showed no significant differences in push-out shear strengths between the two types of coatings evaluated. Differences between 4 and 12 weeks were significant for coating resorption and push-out shear strength but not for bone apposition. Significant enhancement in interfacial shear strengths for bioceramic coated as compared to uncoated implants were seen for smooth-surfaced implants (3.5-5 times greater) but not for rough-surfaced implants at 4 and 12 weeks. Rough implants showed greater mean interfacial strengths than uncoated smooth implants at 4 and 12 weeks (seven times greater) and to coated smooth implants at 12 weeks only (two times greater). Mechanical failure of the bone/coating/implant interface consistently occurred within the bone, even in the case of the poorly crystallized HA coatings, which had almost completely resorbed on rough implants. These results suggest that once early osteointegration is achieved biodegradation of a bioactive coating should not be detrimental to the bone/coating/implant fixation.