Development of an Immersion Model for Tooth Decay Observed via Scanning Electron Microscopy, Atomic Force Microscopy and Flame Atomic Absorption Spectroscopy

Abstract

A model for immersive tooth decay was developed to assess the loss of calcium from hydroxyapatite (calcium phosphate) discs. Hydroxyapatite discs are routinely used as a target model of a tooth. Similarly, immersion in an acidic solution is commonly used to emulate conditions within the human mouth; it is believed that a pH of 3.26 is a reasonable approximation of a biological pH experienced by the mouth upon eating acidic foods.Discs were incubated the acidic solution for one or three months. Acid‐treated hydroxyapatite discs were removed from the solution and dried via vacuum centrifuge before being analyzed; the immersion solution was also retained. Scanning electron microscopy (SEM), atomic force microscopy (AFM) and flame atomic absorption spectroscopy (FAAS) were performed to document the extent of tooth damage. Samples were sputter‐coated with gold prior to SEM analysis, where surface morphology of treated hydroxyapatite discs upon acid damage was monitored. AFM was used to measure the average surface roughness of acid‐treated discs compared to control discs. Disc immersion solution was saved, and calcium dissolution was quantified using FAAS.This research improves on known protocols for evaluating damage to hydroxyapatite discs treated in an acidic immersion assay. By providing a model for the development of caries in teeth, this protocol offers a system for studying the impact of biological and nanobiological materials on tooth decay. SEM surface morphology measurements provided a visual assessment of the erosion of the hydroxyapatite disc when immersed in an acidic solution with changes in the topographic determination of roughness quantified with AFM. FAAS analysis was used to document the release calcium from the hydroxyapatite discs.We have implemented a protocol for analyzing damage caused to teeth as modeled in a hydroxyapatite disc assay, and set standards for analyzing the damage by three complementary techniques.Support or Funding InformationThis research was supported by University of Wisconsin‐Stout Student Research Grant to RDS.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.