Objective Although molecular methods such as quantitative Polymerase Chain Reaction with High-Resolution Melting Curve (qPCR–HRMC) analysis and Restriction Fragment Length Polymorphism (PCR-RFLP) enable accurate identification of Candida spp., their application to denture samples remains limited. This study applied qPCR–HRMC and PCR-RFLP to identify Candida species in denture wearers with and without denture stomatitis. Design Biofilm samples from denture wearers with and without denture stomatitis (n = 40) were collected using swabs and ultrasound, followed by DNA extraction and qPCR–HRMC for direct Candida identification. All samples were cultured on CHROMagar Candida for presumptive identification. When direct identification was not possible, cultured isolates were subjected to qPCR–HRMC. For PCR-RFLP, purified amplicons were digested with a restriction enzyme, and electrophoretic banding patterns were compared with reference strains. Cohen’s kappa coefficient (κ) evaluated the agreement between qPCR–HRMC and CHROMagar Candida. Results qPCR–HRMC successfully identified Candida albicans and Candida tropicalis directly from denture biofilms colonized by a single species. In contrast, identification of Nakaseomyces glabratus, Candida dubliniensis, and mixed-species colonization required prior cultivation. Substantial agreement was observed between CHROMagar™ Candida and qPCR–HRMC (κ = 0.826), with 100% sensitivity for C. albicans and high specificity for N. glabratus (97%) and C. tropicalis (100%). PCR-RFLP showed limited discriminatory capacity. Conclusions qPCR–HRMC proved effective for the direct detection of C. albicans and C. tropicalis in denture biofilms, whereas identification of other species and mixed-species colonization required prior cultivation. PCR-RFLP was not suitable for Candida identification in these samples.
Objectives This study synthesized calcium-containing cyclotriphosphate materials from sodium cyclotriphosphate (NaCTP) using calcium hydroxide [Ca(OH)₂], calcium chloride (CaCl₂), or calcium nitrate [Ca(NO₃)₂], designated Ca(OH)₂-CTP, CaCl₂-CTP, and Ca(NO₃)₂-CTP, respectively, and evaluated their effects on initial enamel erosion. The powders were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Design Bovine enamel blocks (n = 10/group) were allocated to placebo; 0.24% sodium fluoride (NaF); or 0.5% and 1% NaCTP, Ca(OH)₂-CTP, CaCl₂-CTP, or Ca(NO₃)₂-CTP groups. After toothpaste treatment (2 min), blocks underwent four erosive cycles (1 min; pH 3.5). Surface hardness was assessed after treatment and each challenge. Micro-computed tomography measured mineral concentration and lesion depth. Data were analyzed by analysis of variance and Tukey’s test (p < 0.05). Results CaCl₂-CTP and Ca(NO₃)₂-CTP showed partial sodium replacement by EDS and crystalline structures by XRD. For Ca(OH)₂-CTP, no sodium signal was detected by EDS; the material retained characteristic cyclotriphosphate bands by FTIR and exhibited a predominantly amorphous structure by XRD. NaF and NaCTP showed similar mineral loss (p ≥ 0.086). Ca(OH)₂-CTP produced significantly lower hardness loss and mineral depletion than all other groups (p < 0.001) and reduced lesion depth by approximately 50% relative to NaCTP and NaF. Conclusions The Ca(OH)₂/cation-exchange route produced a predominantly amorphous calcium-containing cyclotriphosphate material in which no sodium signal was detected by EDS. This material provided greater protection against initial enamel erosive softening and mineral loss than NaCTP and 0.24% NaF.
