# Functional Competence of a Dentoalveolar Fibrous Joint in Vertebrates

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · 2020 · $383,563

## Abstract

ABSTRACT
A variety of biomechanical stimuli are directed on the dentoalveolar fibrous joint (DAJ) of the masticatory
complex (e.g. chewing on softer diet (SD), therapeutic loads from orthodontic interventions), and can result in
local abnormal deformations and adaptive processes that can lead to aberrant function [1-7]. A systematic
study of the effect of SD on the tooth-crown revealed significant age-related shifts in biological processes in the
periodontal complex (R01DE022032 02/2012-01/2018). Thus, recovery of an adapting joint to its original
stiffness is compromised with age, but the question remained: when the joint is exposed to prolonged aberrant
loads, what is the optimal age range for the joint to recover to its baseline biomechanics should the aberrant
load be substituted with physiologic loads (hard diet (HD))? What is the age range beyond which joint
biomechanics are irreversible? Data from the recovery model (RM) (mice raised to various time points on SD
and switched to HD), will help determine the age range for which functional competence of the joint is
maintained, and help predict when clinical intervention simulated through an experimental tooth movement
(ETM) model is most effective. ETM will also help in identifying the intended reversal of natural biological
processes [8] at the strain-amplified sites of the PDL-entheses. Hypothesis: The functional competence of
the DAJ can be identified as age-related gradients in biological expressions (ΔBE/Δage) and joint
stiffness (ΔS/Δage). From a translational perspective, ETM is effective in an age range that demonstrates
minima in ΔS/Δage. Proposed aims will include: Aim 1: To assess the recovery of functional competence of
adapting fibrous joints with age. Functional competence of an adapted joint will be determined by its ability
to resist shifts in magnitudes and frequencies of biomechanical loads without subsequent pathologic function
[9]; to-date no such data exist. Functional competence will be determined from digital spatiotemporal maps of
changes in periodontal ligament (PDL)-spaces, tooth-bone morphology and joint stiffness (ΔS/Δage) with age
from SD, HD, RM groups. The RM will identify an age range to optimize preservation of the fibrous joint. Aim
2: To assess the mechanobiological processes of an adapting fibrous joint with age. Spatiotemporal
shifts in biological expressions (BE) (ΔBE/Δage – genes and matrix proteins) at the bone, cementum, and the
PDL-entheses from respective age groups will be mapped. Differentially expressed genes, and mineral forming
and resorbing matrix factors at PDL-entheses and the PDL at widened and narrowed regions with age for three
groups (SD, HD, RM) will be correlated. AIM 3: To assess the effect of a proposed age range on
experimental tooth movement resulting in long-term functional competence. Outcome
physicochemical and biological measures will be the same as in Aims 1 and 2 but on ETM group [10]
before, during, and after the proposed ag...

## Key facts

- **NIH application ID:** 9997898
- **Project number:** 5R01DE022032-07
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
- **Principal Investigator:** Sunita P Ho
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $383,563
- **Award type:** 5
- **Project period:** 2012-02-09 → 2022-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9997898

## Citation

> US National Institutes of Health, RePORTER application 9997898, Functional Competence of a Dentoalveolar Fibrous Joint in Vertebrates (5R01DE022032-07). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9997898. Licensed CC0.

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