# Remineralization carious lesions in dentin using the PILP-approach

> **NIH NIH R21** · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · 2020 · $242,250

## Abstract

Project Summary/Abstract
The last decade has seen a shift in the philosophy of dental care towards prevention and minimal-invasive
restorative approaches, promoting tissue repair by remineralization as a key element of dental treatments.
Remineralization of enamel, which is 95% mineral, is an accepted phenomenon with established mechanisms
relying mainly on fluoride release. Those mechanisms, however, do not apply to dentin, as they do not produce
intrafibrillar mineral as demonstrated in our preliminary studies. Dentin is a collagenous tissue, similar to bone,
and requires apatite mineral to form inside collagen fibrils (intrafibrillar) for mechanical reinforcement. We have
shown that the “Polymer-Induced Liquid Precursor” (PILP) approach is suitable and effective to reintroduce
mineral into collagen in vitro restoring the mechanical properties of the tissue, which is critical for its function.
PILP-treatments performed on demineralized specimens recovered their mechanical properties at 50 to 100%
of normal tissue value when evaluated by nanoindentation and 4-point bending tests, respectively. We have
identified two proteins, osteopontin (OPN-10) and phosvitin (PV) in addition to synthetic poly-aspartic acid
(pAsp), among a larger set of possible systems, reported in the literature, that reintroduce oriented apatite
crystallites in the interstices of collagen-I fibrils in dentin matrices. Based on this concept, we propose to
develop PILP-releasing materials and procedures that can be applied to dentin caries and be integrated with a
restorative treatment facilitating long-term collagen remineralization leading to a restoration of tissue function,
ultimately extending the life-time of the tooth and thus reducing the incidents of pulp exposure and endodontic
treatment or tooth loss due to caries.
The proposed reparative procedures will interfere with the current standard of care for caries management in
dentistry that stresses excessive tissue removal. Instead this approach will promote repair, regeneration and
conservation of the natural tissue. Dentin's function is primarily mechanical as it supports the stiff enamel in the
mastication process. That function is lost when bacterial acid dissolves and removes apatite from collagen
fibrils. PILP-mineralization is thus far the only known method to restore this function in vitro in artificial lesions.
We consider this approach a regenerative approach as it rebuilds a weight-bearing tissue which would
otherwise not contribute to the mastication process. Here we propose to test the standard PILP-mineralization
method as well as novel cement formulations that are comprised of PILP-components for their potential to
repair natural caries lesions in vitro as a further step towards translation of the PILP-mineralization concept into
a clinical setting.

## Key facts

- **NIH application ID:** 9980847
- **Project number:** 5R21DE028421-02
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
- **Principal Investigator:** Stefan Friedrich Habelitz
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $242,250
- **Award type:** 5
- **Project period:** 2019-08-01 → 2022-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9980847

## Citation

> US National Institutes of Health, RePORTER application 9980847, Remineralization carious lesions in dentin using the PILP-approach (5R21DE028421-02). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/9980847. Licensed CC0.

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