Development of radiopaque, biocompatible, antimicrobial, micro-particle fillers for micro-CT imaging of simulated periodontal pockets

M Elashiry; M M Meghil; S Kalathingal; A Buchanan; M Rajendran; R Elrefai; M Ochieng; A Elawady; R M Arce; K H Sandhage; C W Cutler

doi:10.1016/j.dental.2017.12.002

Development of radiopaque, biocompatible, antimicrobial, micro-particle fillers for micro-CT imaging of simulated periodontal pockets

Dent Mater. 2018 Apr;34(4):569-578. doi: 10.1016/j.dental.2017.12.002. Epub 2017 Dec 26.

Authors

M Elashiry¹, M M Meghil², S Kalathingal³, A Buchanan³, M Rajendran⁴, R Elrefai⁵, M Ochieng⁶, A Elawady⁴, R M Arce⁴, K H Sandhage⁷, C W Cutler⁴

Affiliations

¹ Department of Oral Biology, Augusta University, Augusta, GA, USA; Department of Periodontics, The Dental College of Georgia at Augusta University, Augusta, GA, USA. Electronic address: melashiry@augusta.edu.
² Department of Oral Biology, Augusta University, Augusta, GA, USA; Department of Periodontics, The Dental College of Georgia at Augusta University, Augusta, GA, USA.
³ Department of Diagnostic Science, The Dental College of Georgia at Augusta University, Augusta, GA, USA.
⁴ Department of Periodontics, The Dental College of Georgia at Augusta University, Augusta, GA, USA.
⁵ Department of Prosthodontics, The Dental College of Georgia at Augusta University, Augusta, GA, USA.
⁶ School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA.
⁷ School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, USA; School of Materials Engineering, Purdue University, West, Lafayette, IN, USA.

PMID: 29287980
DOI: 10.1016/j.dental.2017.12.002

Abstract

Objectives: Approximately 10⁹ bacteria can be harbored within periodontal pockets (PP) along with inflammatory byproducts implicated in the pathophysiology of systemic diseases linked to periodontitis (PD). Calculation of this inflammatory burden has involved estimation of total pocket surface area using analog data from conventional periodontal probing which is unable to determine the three-dimensional (3-D) nature of PP. The goals of this study are to determine the radiopacity, biocompatibility, and antimicrobial activity of transient micro-particle fillers in vitro and demonstrate their capability for 3-D imaging of artificial PP (U.S. Patent publication number: 9814791 B2).

Methods: Relative radiopacity values of various metal oxide fillers were obtained from conventional radiography and micro-computed tomography (μCT) using in vitro models. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays were used to measure the biocompatibility of calcium tungstate (CaWO₄) particles by determination of viable keratinocytes percentage (%) after exposure. After introducing an antibacterial compound (K21) to the radiopaque agent, antimicrobial tests were conducted using Porphyromonas gingivalis (P. gingivalis) and Streptococcus gordonii (S. gordonii) strains and blood agar plates.

Results: CaWO₄ micro-particle-bearing fillers exhibited an X-ray radiopacity distinct from tooth structures that enabled 3-D visualization of an artificial periodontal pocket created around a human tooth. MTT assays indicated that CaWO₄ micro-particles are highly biocompatible (increasing the viability of exposed keratinocytes). Radiopaque micro-particle fillers combined with K21 showed significant antimicrobial activity for P. gingivalis and S. gordonii.

Significance: The plausibility of visualizing PP with 3-D radiographic imaging using new radiopaque, biocompatible, transient fillers was demonstrated in vitro. Antibacterial (or other) agents added to this formula could provide beneficial therapeutic features along with the diagnostic utility.

Keywords: Calcium tungstate; Cone-beam computed tomography; Diagnosis; Imaging; Periodontal pocket; Three-dimensional.

Published by Elsevier Ltd.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Anti-Infective Agents / chemistry*
Biocompatible Materials / chemistry*
Calcium Compounds / chemistry*
Humans
Imaging, Three-Dimensional
In Vitro Techniques
Particle Size
Periodontal Pocket / diagnostic imaging*
Periodontal Pocket / microbiology
Porphyromonas gingivalis / drug effects
Quaternary Ammonium Compounds / chemistry*
Silanes / chemistry*
Streptococcus gordonii / drug effects
Tungsten Compounds / chemistry*
X-Ray Microtomography*

Substances

Anti-Infective Agents
Biocompatible Materials
Calcium Compounds
K21 compound
Quaternary Ammonium Compounds
Silanes
Tungsten Compounds
calcium tungstate