Physicochemical Properties of Bioactive Polymeric Composites: Effects of Resin Matrix and the Type of Amorphous Calcium Phosphate Filler

2005 ◽  
Vol 284-286 ◽  
pp. 737-740 ◽  
Author(s):  
Drago Skrtic ◽  
S.Y. Lee ◽  
Joseph M. Antonucci ◽  
D.W. Liu

This study explores how a) the resin grafting potential for amorphous calcium phosphate (ACP) and b) particle size of ACP affects physicochemical properties of composites. Copolymers and composites were evaluated for biaxial flexure strength (BFS), degree of vinyl conversion (DC), mineral ion release and water sorption (WS). Milled ACP composites were superior to unmilled ACP composites and exhibited 62 % and 77 % higher BFS values (dry and wet state, respectively). The average DC of copolymers 24 h after curing was 80 %. DC of composites decreased 10.3 % for unmilled Zr-ACP and 4.6 % for milled Zr-ACP when compared to the corresponding copolymers. The WS increased as follows: copolymers < milled Zr-ACP composites < unmilled Zr-ACP composites. The levels of Ca and PO4 released from both types of composites increased with the increasing EBPADMA/TEGDMA ratio in the matrix. They were significantly above the minimum necessary for the redeposition of HAP to occur. No significant consumption of released calcium by the carboxylic groups of methacryloxyethyl phtahalate (MEP) occurred at a mass fraction of 2.6 % of MEP in the resin. Improvements in ACP composite’s physicochemical properties are achieved by fine tuning of the resin and improved ACP’s dispersion within the polymer matrix after ball-milling.


2021 ◽  
pp. 1-10
Author(s):  
Ahmed Sleibi ◽  
Anwar R. Tappuni ◽  
Aylin Baysan

Different formulas of topical fluoride have been used to manage root carious lesions. This clinical trial aimed to investigate the efficacy of a dental varnish containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and fluoride compared with fluoride alone in reversing/arresting root caries in xerostomic patients over 1 year. A total of 80 patients (age range 45–92 years) with primary root caries (<i>n</i> = 184 root carious lesions) and unstimulated salivary flow rate of &#x3c;0.2 mL/min were randomly allocated to receive either dental varnish containing CPP-ACP and 5% fluoride (group 1: MI varnish; GC, Japan) (<i>n</i> = 41, 83 lesions), or dental varnish with 5% fluoride alone (group 2: NUPRO White; Dentsply, USA) (<i>n</i> = 39, 101 lesions). Clinical assessments with Severity Index (SI) for root caries, DIAGNOdent measurements, and varnish application were carried out at baseline, 3, 6, and 12 months. Standard oral hygiene instructions with 1,450 ppm fluoride toothpastes were provided for both groups. After 3 months, 63.9% (<i>n</i> = 46) of root caries in group 1 became hard (SI: 0) compared with 39.3% (<i>n</i> = 35) in group 2 (<i>p</i> &#x3c; 0.01). After 6 and 12 months, the differences in SI were insignificant (group 1, <i>n</i> = 60, 83.3%) (group 2, <i>n</i> = 66, 74.2%) (<i>p</i> = 0.36), and (group 1, <i>n</i> = 60, 89.6%) (group 2, <i>n</i> = 67, 81.7%, <i>n</i> = 1 soft, 1.2%) (<i>p</i> = 0.29), respectively. In both groups, noncavitated leathery lesions were more likely to become hard when compared to the cavitated root caries. A significant decrease in plaque index, surface roughness, lesion dimension, and DIAGNOdent readings with a significant increase in lesion distance from the gingival margin was reported in both groups (<i>p</i> &#x3c; 0.05). This study has provided evidence that fluoride dental varnish either with or without calcium and phosphate has the potential to arrest/reverse root caries, especially noncavitated lesions for patients with xerostomia.


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