{'fraction_non_alphanumeric': 0.02324455205811138, 'fraction_numerical': 0.006779661016949152, 'mean_word_length': 5.863787375415282, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Leachability and Cytotoxicity of an Experimental Polymeric ACP Composite.

Amorphous calcium phosphate (ACP)-based dental composites represent a new generation of bioactive, remineralizing dental materials of particular importance in preventive dentistry, orthodontics and endodontics [1]. When embedded in polymerized methacrylate matrices and exposed to aqueous environments, ACP can convert spontaneously into thermodynamically stable apatite and release sufficient levels of remineralizing Ca and PO4 ions to regenerate mineral-deficient tooth structures [2, 3]. The extensive physicochemical studies of these experimental materials performed in our group have emphasized the importance of reviewing the structure/property relationships for an appreciation of the interactions between the bioactive ACP filler, the polymeric phase of these materials and simulated oral environment [4–6]. Towards this end, much lesser attention has been given to the factors that control the biocompatibility of ACP composites. We have conveniently used the degree of vinyl conversion (DVC) of the composite attained upon polymerization to indirectly assess the overall potential of unreacted residual monomers to leach from ACP composites formulated as pit and fissure sealants and/or orthodontic adhesives [7]. 
 
In this study, we identify and quantify leachables and assess cellular responses to an experimental ACP composite intended for application as a remineralizing endodontic sealer. Our goals were: 1) to assess the suitability of 1H nuclear magnetic resonance (1H NMR) spectroscopy as viable alternative to commonly used chromatographic techniques for quantitative leachability studies, and 2) to determine the effect(s) of composite extracts on the morphology and viability of murine preosteoblasts (MC3T3-E1 cells). The underlying working hypothesis was that, due to the high DVCs attained in the experimental ACP composite, its leachability, and in turn, its cytotoxicity will not exceed the cytotoxicity of the commercial endodontic sealer selected as a control.