Carbon Nanotubes in Conservative Dentistry and Endodontics: A Critical Appraisal of Mechanical, Antimicrobial and Regenerative Claims

Résumé fourni par la source

Carbon nanotubes (CNTs) have been advanced as reinforcing, antibacterial and bioactive additives for the materials used in conservative dentistry and endodontics, and the laboratory literature on this theme has expanded steadily over the past two decades. Enthusiasm derives largely from the intrinsic stiffness, aspect ratio and tunable surface chemistry of the isolated nanotube. The properties of an isolated tube and the properties of that tube once dispersed within a methacrylate, glass-ionomer, epoxy-resin or calcium silicate matrix are separated by processing steps that dental studies seldom characterise, and this gap shapes much of the disagreement in the field. This critical narrative review evaluates the evidence for CNT modification of restorative resins, dentine adhesives, acid-base cements, root canal sealers, vital pulp therapy materials and pulp-dentine tissue engineering scaffolds, together with the diagnostic and safety literature that constrains translation. Sources were identified through structured searching of biomedical and multidisciplinary bibliographic indexes and citation tracking, and were appraised for design adequacy, measurement validity, dose-response coherence and attribution of effect. Three findings dominate. First, mechanical benefit is real but narrow, confined to loadings near or below 1 per cent by weight, non-monotonic with concentration, and frequently matched or exceeded by conventional ceramic fillers tested in parallel. Second, most reported antimicrobial effects are confounded by silver, chlorhexidine or other payloads carried on the nanotube, so the independent contribution of the CNT itself remains poorly resolved. Third, regenerative claims rest predominantly on osteogenic and angiogenic surrogates in cells of dental origin rather than on odontoblastic differentiation or tubular dentine formation, and no clinical study in conservative dentistry or endodontics was identified. Safety evaluation is dominated by inhalation and fibre-pathogenicity models that map poorly onto a set, encapsulated dental material, while release, wear and degradation data are largely absent. Priorities include standardised reporting of nanotube provenance and dispersion state, dose-response designs with ceramic comparators, attribution-controlled antimicrobial testing, odontogenic endpoints and exposure assessment across the material life cycle.

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