Dentin remineralization in acid challenge environment via PAMAM and calcium phosphate composite.
The objective of this study was to investigate the effects of poly (amido amine) (PAMAM), composite with nanoparticles of amorphous calcium phosphate (NACP), and the combined PAMAM+NACP nanocomposite treatment, on remineralization of demineralized dentin in a cyclic artificial saliva/lactic acid environment for the first time.



Dentin specimens were prepared and demineralized with 37% phosphoric acid for 15s. Four groups were prepared: (1) dentin control, (2) dentin coated with PAMAM, (3) dentin with NACP composite, (4) dentin with PAMAM+NACP. Specimens were treated with a cyclic artificial saliva/lactic acid regimen for 21days. Acid neutralization and calcium (Ca) and phosphate (P) ion concentrations were measured. The remineralized dentin specimens were examined by scanning electron microscopy (SEM) and hardness testing.



NACP nanocomposite had mechanical properties similar to commercial control composites (p>0.1). NACP composite had acid-neutralization and Ca and P ion release capability. PAMAM or NACP composite each alone achieved remineralization and increased the hardness of demineralized dentin (p<0.05). PAMAM+NACP nanocomposite achieved the greatest mineral regeneration in demineralized dentin and the greatest hardness increase in demineralized dentin, which approached the hardness of healthy dentin (p>0.1).



The superior remineralization efficacy of PAMAM+NACP was demonstrated for the first time. PAMAM+NACP induced remineralization in demineralized dentin in an acid challenge environment, when conventional remineralization methods such as PAMAM did not work well. The novel PAMAM+NACP composite approach is promising for a wide range of dental applications to inhibit caries and protect tooth structures.
State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China; Department of Endodontics, Periodontics and Prosthodontics, University of Maryland School of Dentistry, Baltimore, MD 21201, USA.
Kunneng
K
Liang
Department of Endodontics, Periodontics and Prosthodontics, University of Maryland School of Dentistry, Baltimore, MD 21201, USA.
Michael D
MD
Weir
Department of Endodontics, Periodontics and Prosthodontics, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; Department of Orthodontics, School of Stomatology, Capital Medical University, Beijing, China.
Xianju
X
Xie
Department of Endodontics, Periodontics and Prosthodontics, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; VIP Integrated Department, Stomatological Hospital of Jilin University, Changchun, China.
Lin
L
Wang
Department of Endodontics, Periodontics and Prosthodontics, University of Maryland School of Dentistry, Baltimore, MD 21201, USA.
Mark A
MA
Reynolds
State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China. Electronic address: jiyaoliscu@163.com.
Jiyao
J
Li
Department of Endodontics, Periodontics and Prosthodontics, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; Center for Stem Cell Biology & Regenerative Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Mechanical Engineering, University of Maryland Baltimore County, Baltimore County, MD 21250, USA. Electronic address: hxu@umaryland.edu.
Hockin H K
HH
Xu
D002130:Calcium Phosphates; D003731:Dental Caries; D003804:Dentin / Q000737:chemistry*; D006801:Humans; D053761:Nanocomposites; D053758:Nanoparticles; D012464:Saliva, Artificial; D014089:Tooth Remineralization
D002130:Calcium Phosphates; D012464:Saliva, Artificial
Acid challenge; Calcium phosphate nanoparticles; Composite; Demineralization; Dentin remineralization; PAMAM