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Usefulness of subtraction thermography in the evaluation of blood vessels and lymphatic vessels in the dental pulp

MetadataDetails
Publication Date2024-01-01
JournalActa of Bioengineering and Biomechanics
AuthorsMaria Wiƛniewska-Wrona, Maria Szymonowicz, Piotr Kuropka, Zbigniew Rybak, Natalia Struzik
InstitutionsWrocƂaw University of Science and Technology, WrocƂaw University of Environmental and Life Sciences
AnalysisFull AI Review Included

Technical Documentation & Analysis: Subtraction Thermography in Dental Pulp

Section titled “Technical Documentation & Analysis: Subtraction Thermography in Dental Pulp”

This document analyzes the research paper “Usefulness of subtraction thermography in the evaluation of blood vessels and lymphatic vessels in the dental pulp” to highlight the critical role of advanced diamond materials in precision thermal science and to drive sales for 6CCVD’s specialized MPCVD diamond products.


The study successfully validates subtraction thermography (ST) as a non-invasive, quantitative method for assessing vascular activity and inflammation in dental pulp. The findings underscore the necessity of materials with superior thermal properties for high-precision bioengineering applications.

  • Core Achievement: Subtraction thermography (ST) effectively identified differences in heat dissipation rates ($\Delta T$) across tooth cross-sections, correlating these differences with the density of vascular beds (blood and lymphatic vessels).
  • Mechanism: The technique isolates thermal changes caused by tissue heterogeneity (density, fluid flow) by subtracting thermograms taken at $t = 0$ s and $t = 120$ s of free cooling.
  • Key Finding: Caries-affected teeth showed distinct areas of fluid flow and heat release, indicating increased vascularization and inflammation intensity.
  • Precision Requirement: The methodology relies on extremely precise temperature control ($T_0 = 40 \pm 0.5$ °C) and high-resolution thermal imaging (640 $\times$ 320 pixels).
  • Material Relevance: The use of a diamond saw for sample preparation and the reliance on precise thermal conductivity measurements highlight the need for high-performance diamond materials in both tooling and advanced sensor/window applications.
  • 6CCVD Value Proposition: 6CCVD provides the high-thermal-conductivity Single Crystal Diamond (SCD) and Polycrystalline Diamond (PCD) substrates necessary to replicate or advance this research, particularly in creating stable thermal stages and high-transparency IR windows.

The following hard data points were extracted from the experimental methodology:

ParameterValueUnitContext
Initial Heating Temperature ($T_0$)40 $\pm$ 0.5°CStandard thermal pulse applied to samples
Long Pulse Heating Temperature ($T_0$)45 $\pm$ 0.5°CUsed for experimental temperature dependence tests
Ambient Temperature ($T_{amb}$)22 $\pm$ 0.5°CFree cooling environment
Cooling Duration120sTotal time recorded for thermogram sequence
Camera Resolution640 $\times$ 320pixelsFLIR P640 thermal imaging camera
Initial Sampling Frequency30HzRaw recording rate of thermograms
Analysis Sampling Frequency1HzFrequency used for statistical analysis (low dynamics)
IR Lamp Power250WHeat source for uniform sample heating
IR Lamp Distance12cmDistance from sample during heating
Imaging Distance$\approx$ 3cmDistance using spacer ring
Absolute Pulp Temperature Limit41.5°CMaximum temperature limit for restorative procedures

The subtraction thermography survey was conducted using precise thermal control and high-resolution imaging to analyze transient cooling behavior.

  1. Sample Preparation: Healthy (n=10) and carious (n=14) molars and premolars were freshly extracted and cut in the transverse axis using a diamond saw.
  2. Thermal Pulse Application: Samples were heated uniformly using a 250 W IR lamp (12 cm distance) to an initial temperature ($T_0$) of 40 $\pm$ 0.5 °C (or 45 $\pm$ 0.5 °C for long pulse tests).
  3. Thermogram Recording: A sequence of thermograms was recorded during 120 s of free cooling at ambient temperature ($T_{amb} = 22 \pm 0.5$ °C) using a high-resolution FLIR P640 camera (640 $\times$ 320 pixels) from a distance of $\approx$ 3 cm.
  4. Subtraction Analysis: Digital image analysis software (ThermaCAM Researcher Pro 2.8 and MatLab) was used to perform subtraction: $C(i, j) = Standarization [A(i, j) - B(i, j)]$, where A is the thermogram at $t=0$ s and B is the thermogram at $t=120$ s.
  5. ROI Definition: Three Regions of Interest (ROI) were defined: ROI1 (entire cross-section), ROI2 (smallest temperature difference, indicating highest vascular bed density), and ROI3 (largest temperature difference, indicating homogeneous structure).
  6. Index Calculation: Dimensionless temperature indices (C(t)) and rates of temperature change ($I(i)$) were calculated based on the cooling curves of ROI2 and ROI3.
  7. Validation: Thermographic results were compared against the “gold standard” of lymphoscintigraphy and X-ray examination.

This research demonstrates the critical link between material thermal properties and advanced diagnostic imaging. 6CCVD’s MPCVD diamond products are ideally suited to support and extend this type of high-precision thermal science, both through superior tooling and advanced sensor integration.

Research Requirement / Challenge6CCVD Solution & CapabilityApplicable Materials
Precision Sample PreparationThe study required cutting samples with a diamond saw. 6CCVD supplies high-quality PCD blanks and custom-machined components for superior, durable, and precise cutting tools, minimizing thermal damage during preparation.PCD Blanks (Tooling Grade)
High-Resolution IR ImagingThermography relies on the transmission of infrared radiation. SCD is an ideal material for protective windows, lenses, or beam splitters due to its exceptional IR transparency and thermal stability.Optical Grade SCD (Polished to Ra < 1 nm)
Thermal Stage StabilityMaintaining precise temperature control ($T_{amb} = 22 \pm 0.5$ °C) is crucial. 6CCVD SCD/PCD substrates offer the highest known thermal conductivity (up to 2000 W/mK), enabling the construction of highly stable thermal stages or active heat sinks for experimental control.High Thermal Conductivity SCD/PCD
Advanced Sensor IntegrationFuture research may require integrating micro-sensors or electrodes directly onto the sample stage for simultaneous thermal and electrochemical analysis of fluid flow.Custom SCD/PCD Wafers (Up to 125mm)
Electrochemical Fluid AnalysisThe paper discusses fluid flow and inflammation markers. Boron-Doped Diamond (BDD) is the premier electrode material for stable, sensitive electrochemical detection of biological species in complex media.Heavy Boron-Doped Diamond (BDD)
Custom MetalizationFor integrating thermal sensors or creating specific heating elements (e.g., resistive layers) on the diamond substrate, custom metal contacts are necessary.Metalization Services: Au, Pt, Ti, W, Cu (Internal capability)

6CCVD’s in-house PhD team specializes in the thermal, optical, and electrochemical properties of diamond. We can assist researchers in selecting the optimal diamond grade (SCD, PCD, or BDD) and geometry (custom dimensions up to 125mm, thicknesses from 0.1 ”m to 500 ”m) required for similar Thermophotonic Lock-in Imaging (TPLI) or Active Dynamic Thermography projects.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

Purpose Caries or iatrogenic thermal trauma of the teeth have a significant impact on the dental pulp structure connected with stimulation of angiogenesis and lymphangiogenesis. Therefore, the aim of the study was to identify the difference in the rate of heat dissipation by vessels present in the dental pulp. Methods Freshly extracted healthy and carious teeth were cut on a diamond saw and subjected to thermographic testing. Tooth samples were heated to 45±0,5°C using a lamp. A high-resolution thermal imaging camera was used to record the series of thermograms until the samples reached a temperature of 25±0,5°C. Results Thermographic examination of healthy and cariously changed teeth revealed areas of increased tissue fluid flow combined with heat release, which may indirectly indicate the existence of vessels in these areas. On a thermal imaging camera, variations in the rate of heating or cooling across several cross-sectional sections of the same tooth indicate changes in the dental structure’s density. Conclusions In caries-affected teeth, intracanalicular fluid flows are different than those of healthy teeth. Therefore, it can be concluded that the pulp vessels enabling circulation of body fluids - blood and lymphatic - increases with the intensity of inflammation. Maintaining the homeostasis of the dental pulp depends heavily on the circulation of bodily fluids within the dental organ.