Abdulrahman A Balhaddad1, Maria S Ibrahim2, Michael D Weir3, Hockin H K Xu4, Mary Anne S Melo5. 1. Ph.D. Program in Biomedical Sciences, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; Department of Restorative Dental Sciences, Imam Abdulrahman Bin Faisal University, College of Dentistry, Dammam, Saudi Arabia. 2. Ph.D. Program in Biomedical Sciences, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; Department of Preventive Dental Sciences, Imam Abdulrahman Bin Faisal University, College of Dentistry, Dammam, Saudi Arabia. 3. Ph.D. Program in Biomedical Sciences, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; Biomaterials & Tissue Engineering Division, Department of Advanced Oral Sciences and Therapeutics, University of Maryland School of Dentistry, Baltimore, MD 21201, USA. 4. Ph.D. Program in Biomedical Sciences, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; Biomaterials & Tissue Engineering Division, Department of Advanced Oral Sciences and Therapeutics, University of Maryland School of Dentistry, Baltimore, MD 21201, USA. Electronic address: HXu2@umaryland.edu. 5. Ph.D. Program in Biomedical Sciences, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; Division of Operative Dentistry, Department of General Dentistry, University of Maryland School of Dentistry, Baltimore, MD 21201, USA. Electronic address: mmelo@umaryland.edu.
Abstract
OBJECTIVES: Dental plaque build-up on the cervical area adjacent to gingival margins is a trigger factor for secondary caries around restored root caries lesions. Dimethylaminohexadecyl methacrylate (DMAHDM) and amorphous calcium phosphate nanoparticles (NACP) impart anti-caries effect by reducing the bacterial growth and releasing high concentrations of calcium and phosphate ions, respectively. The present study explored the optimization and formulation of dental composite with increased concentration of DMAHDM combined with NACP and its effect on mechanical behavior and antibacterial response. METHODS: DMAHDM was incorporated into dental composite formulation at 3% and 5% with 20% NACP fillers. Mechanical properties were assessed by flexural strength and elastic modulus. The cationic charge density of the samples was determined using fluorescein staining assay. A human saliva-derived microcosm biofilm model was used to assess antibacterial response via colony-forming units, metabolic activities, lactic acid production, and live/dead assay. Surface roughness was measured after 48h-biofilm formation. RESULTS: The viability of human saliva microcosm biofilms was DMAHDM concentration-dependent, where all the microbiological assays were substantially reduced in the presence of 5%DMAHDM. The increased DMAHDM concentration mirrors an increased surface charge density of composites by 8-12 folds and reduced the growth of cariogenic species by 2-5 log (p≤0.05). Metabolic activity and lactic acid were reduced by 70-90% and 48-99%, respectively. Increasing DMAHDM concentration up to 5% and its association with NACP fillers did not adversely affect the mechanical properties. SIGNIFICANCE: A highly potent antibiofilm bioactive composite for root caries restorations having DMAHDM-NACP could be flexibly tailored during formulation without detrimental outcome for mechanical function. The enhanced antibacterial performance of the novel bioactive composite has great potential to suppress the dental plaque build-up that triggers secondary caries around the restored root caries lesions.
OBJECTIVES: Dental plaque build-up on the cervical area adjacent to gingival margins is a trigger factor for secondary caries around restored root caries lesions. Dimethylaminohexadecyl methacrylate (DMAHDM) and amorphous calcium phosphate nanoparticles (NACP) impart anti-caries effect by reducing the bacterial growth and releasing high concentrations of calcium and phosphate ions, respectively. The present study explored the optimization and formulation of dental composite with increased concentration of DMAHDM combined with NACP and its effect on mechanical behavior and antibacterial response. METHODS:DMAHDM was incorporated into dental composite formulation at 3% and 5% with 20% NACP fillers. Mechanical properties were assessed by flexural strength and elastic modulus. The cationic charge density of the samples was determined using fluorescein staining assay. A human saliva-derived microcosm biofilm model was used to assess antibacterial response via colony-forming units, metabolic activities, lactic acid production, and live/dead assay. Surface roughness was measured after 48h-biofilm formation. RESULTS: The viability of human saliva microcosm biofilms was DMAHDM concentration-dependent, where all the microbiological assays were substantially reduced in the presence of 5%DMAHDM. The increased DMAHDM concentration mirrors an increased surface charge density of composites by 8-12 folds and reduced the growth of cariogenic species by 2-5 log (p≤0.05). Metabolic activity and lactic acid were reduced by 70-90% and 48-99%, respectively. Increasing DMAHDM concentration up to 5% and its association with NACP fillers did not adversely affect the mechanical properties. SIGNIFICANCE: A highly potent antibiofilm bioactive composite for root caries restorations having DMAHDM-NACP could be flexibly tailored during formulation without detrimental outcome for mechanical function. The enhanced antibacterial performance of the novel bioactive composite has great potential to suppress the dental plaque build-up that triggers secondary caries around the restored root caries lesions.
Authors: Hanan Filemban; Ghalia Bhadila; Xiaohong Wang; Mary Ann S Melo; Thomas W Oates; Michael D Weir; Jirun Sun; Hockin H K Xu Journal: J Dent Sci Date: 2021-10-14 Impact factor: 3.719
Authors: Abdulrahman A Balhaddad; Mohammed S AlQranei; Maria S Ibrahim; Michael D Weir; Frederico C Martinho; Hockin H K Xu; Mary Anne S Melo Journal: Int J Mol Sci Date: 2020-10-15 Impact factor: 5.923
Authors: Abdulrahman A Balhaddad; Isadora M Garcia; Haifa Maktabi; Maria Salem Ibrahim; Qoot Alkhubaizi; Howard Strassler; Fabrício M Collares; Mary Anne S Melo Journal: Restor Dent Endod Date: 2021-09-24