# Dental Compression Analysis Using Confined Compression and Imagining

> **NIH NIH R01** · JLDRUMMOND CONSULTING · 2021 · $321,182

## Abstract

SUMMARY
 Our preliminary data indicated that aging a restorative dental composite in an esterase
enzyme in artificial saliva (AS) resulted in a significant decrease in diametral strength relative to
specimens aged water with or without an acid. Building on this data, this research will utilize a
dentin ring containing a composite specimen to the structural integrity of dentin-adhesive and
adhesive-composite interfaces subjected to simulated oral environments with two model oral
bacteria (cariogenic S. mutans and S. sanguinis) and incubation in the presence of esterase
enzyme in AS media. In addition, the specimens will be subjected to axial and radial cyclic
loading within this dentin-adhesive-composite ring to simulate a class I restoration. Experiments
with the two Streptococcus strains will allow us to determine whether cariogenic incubation
conditions and/or biofilm growth and expression of glucsoyltransferases (gtfB, a key enzyme in
the production of extracellular matrix formation in cariogenic biofilms) significantly impact the
structural integrity of the test specimens. Inclusion of esterases will allow us to test whether
these enzymes degrade and reduce the strength of dentin-adhesive-composite bonds, as we
have shown previously with composites. Static tests will determine the role aqueous
geochemical conditions (either abiotic or biotically-induced) play in attacking the structural
integrity of the test specimens, and dynamically cycled compression will allow us to determine
the impact of simulated forces from mastication to more realistically model stress in vivo.
Analysis of the degradation products leaching from the interfaces and bulk composite will be
quantitatively characterized by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) for
inorganic components of the composite (e.g. Zr, Si, and Ti), and by liquid chromatography/
tandem MS (LC-MS/MS) for polymer degradation products. Micro- and nano-imaging analysis of
the dentin-adhesive-composite volumes (interfaces, pores, and cracks) should aid in clarification
of the sequence of events leading to clinical failure of dental composite restorations. It is
anticipated that significant differences will be observed between and among the bacteria
incubations versus the esterase enzyme in AS environments with respect to control specimens
(uncycled and aged 120 d in AS). It appears that behavior of dental composites subjected to
multiaxial loading in these two environments has not been reported on in the literature to date.
Dental composites are subjected to extreme chemical and mechanical conditions in the oral
environment, which contribute to the degradation and ultimate failure of the material in vivo.

## Key facts

- **NIH application ID:** 10173749
- **Project number:** 5R01DE027596-03
- **Recipient organization:** JLDRUMMOND CONSULTING
- **Principal Investigator:** James L Drummond
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $321,182
- **Award type:** 5
- **Project period:** 2019-06-01 → 2023-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10173749

## Citation

> US National Institutes of Health, RePORTER application 10173749, Dental Compression Analysis Using Confined Compression and Imagining (5R01DE027596-03). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10173749. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*