WO2020113324A1

WO2020113324A1 - An optical periodontal probe comprising a thermochromic material for measuring depth and/or temperature of a periodontal pocket

Info

Publication number: WO2020113324A1
Application number: PCT/CA2019/051733
Authority: WO
Inventors: Rejean Munger; Claire MCLAUGHLIN; Cecilia ODONKOR
Original assignee: Winterra Global Technologies Inc
Current assignee: Winterra Global Technologies Inc
Priority date: 2018-12-03
Filing date: 2019-12-03
Publication date: 2020-06-11
Anticipated expiration: 2021-06-03

Abstract

The present invention provides a photonic periodontal probe for measuring depth and/or temperature of a periodontal pocket. The periodontal probe comprises: a handle and an optically transmissive probe tip; said handle comprising a light source for illuminating said probe tip and a detection means for detecting spectrum and intensity of light reflected from said probe tip; said probe tip having a proximal end connected to the handle and an opposite distal end for insertion into the periodontal pocket; and said probe tip having thermochromic material and a solid carrier material, wherein temperature of said periodontal pocket is determined from the wave length dependence reflected back to the detection means from the probe tip; and wherein the depth of the periodontal pocket is determined from the intensity of light reflected back to the detection means from probe tip.

Description

An Optical Periodontal Probe Comprising a Thermochromic Material for Measuring Depth and/or Temperature of a Periodontal Pocket

Field of the Invention

The present invention relates to the field of dentistry, specifically the periodontal diagnostic area. In particular, this invention relates to an optical periodontal probe comprising a thermochromic material for measuring depth and/or temperature of a periodontal docket.

Background

Periodontal disease is a progressive inflammatory disease affecting the tissues surrounding the teeth. While in early stages, the gums are swollen and bleed. To monitor the progression of periodontal disease a dental professional periodically measures the depths of the periodontal pockets surrounding the teeth. Periodontal disease is typically diagnosed by measuring any periodontal pockets around the teeth using a periodontal probe.

Periodontal pockets are defined as pathologic deepened gingival sulcus (i.e. the area of separation between the surrounding gingival tissue and the surface of the encompassed tooth) which is the result of detachment of gingiva from tooth. As periodontal disease progresses, the relative depth of the periodontal pocket increases. Measurements are usually taken in millimeters.

Conventional periodontal probes are typically one-piece mechanical devices made of surgical steel which have lines, marks or colours (1 mm or 2mm spacing) to indicate the depth that the probe penetrates into the pocket between the tooth and the gum. The pocket depth measurement is performed by a highly trained practitioner who must control the pressure applied and read depth from markings (1 mm or 2mm spacing) on the periodontal probe tip. Conventional probing requires the operator to stop and record the depth of the periodontal pocket at least after the measurement of every tooth, or an assistant is required to record the measurements. There is also a problem of subjectivity. Different dental professionals may have different techniques or may view the periodontal probe at a different angle when taking measurements on different days.

While pocket depth is typically used to diagnose and monitor periodontal disease it may not be the best indicator of disease as it reflects the total history of the disease process and does not necessarily reflect the current inflammatory state of the involved tissue. Pocket depth cannot discriminate between currently active and inactive individual periodontal pockets. Increases in temperature of the periodontal pocket due to inflammation may be used as an indicator of periodontal disease. Pockets with active periodontal disease have higher temperatures than healthy pockets of anatomically equivalent teeth. In order for temperature to be a useful diagnostic tool for periodontal disease, differences among individuals and among the periodontal pockets of the same individual must be taken into consideration. The subgingival temperature depends on many physiological and external factors, for example whether or not the individual smokes. Posterior sites are generally hotter than anterior sites and the temperature is higher in the mandible than in the maxillae.

Thermochromic liquid crystals, one of a family of materials called thermochromics, change colour as a function of temperature and have been used in medical and dental settings to measure temperature. See, for example, U.S. 5,725,373 which teaches a periodontal probe tip made of strong flexible plastic with a thermochromatic plastic ingredient which changes colour above 100°F. The probe of U.S. 5,725,373 uses a graduated marking to measure periodontal depth and as such still has a number of the deficiencies associated with conventional probes.

Summary of the Invention

It is an object of the present invention to provide an optical periodontal probe comprising a thermochromic material for measuring depth and/or temperature of a periodontal pocket. In accordance with an aspect of the present invention, there is provided a photonic periodontal probe for measuring depth and/or temperature of a periodontal pocket, the periodontal probe comprising: a handle and an optically transmissive probe tip; said handle comprising one or more light sources for illuminating said probe tip and a detection means for detecting spectrum and intensity of light reflected from said probe tip; said probe tip having a proximal end connected to the handle and an opposite distal end for insertion into the periodontal pocket; and said probe tip having thermochromic material and a solid carrier material, wherein temperature of said periodontal pocket is determined from the wave length dependence reflected back to the detection means from the probe tip; and wherein the depth of the periodontal pocket is determined from the intensity of light reflected back to the detection means from probe tip.

Brief Description of the Figures

Figure 1 illustrates examples of spectrum change with temperature. Figure 2 illustrates examples of signal strength with thickness.

Figure 3 illustrates an exemplary probe model used for evaluating dimensions and ergonomics.

Figure 4 illustrates measured intensity change versus wavelength during sample cooling. Figure 5 illustrates measured intensity change versus wavelength during sample heating. Figure 6 illustrates normalised intensity change versus wavelength during sample cooling. Figure 7 illustrates normalised intensity change versus wavelength during sample heating. Figure 8 illustrates normalised intensity change versus temperature during sample cooling. Figure 9 illustrates normalised intensity change versus temperature during sample heating. Figure 10 illustrates binned intensity change versus temperature during sample cooling. Figure 1 1 illustrates binned intensity change versus temperature during sample heating. Figure 12 illustrates binned intensity versus temperature during sample cooling

Figure 13 illustrates binned intensity change versus temperature during sample heating. Figure 14 illustrates absolute intensity ratio versus temperature during sample cooling. Figure 15 illustrates absolute intensity ratios versus temperature during sample heating. Figure 16 illustrates mean and standard deviation of absolute ratios during sample cooling. Figure 17 illustrates mean and standard deviation of absolute ratios during sample heating. Figure 18 illustrates binned intensity change versus temperature during sample cooling. Figure 19 illustrate binned intensity change versus temperature during sample heating. Figure 20 illustrates calibration and measured intensity change during sample cooling. Figure 21 illustrates calibration and measured intensity change during sample heating. Figure 22 illustrates error graphs showing respective temperature minima during cooling. Figure 23 illustrates error graphs showing respective temperature minima during heating. Figure 24 illustrates calibration and measured intensity change versus temperature range Figure 25 is a photograph of the experimental setup.

Figure 26 is a photograph of the sample measurement site Figure 27 is a photograph of the sample measurement site during data collection.

Figure 28 provides data analysis for wavelength selection

Figure 29 provides data analysis for temperature calibration algorithm.

Figure 30 illustrates depth vs signal for hybrid 0.6% TLC.

Figure 31 illustrates calibration and measured right singular vectors during sample heating. Figure 32. illustrates calibration and measured right singular vectors during sample heating. Figure 33 illustrates error graphs showing respective temperature minima, 30.0 - 30.5. Figure 34 illustrates error graphs showing respective temperature minima, 33.0 - 33.5.

Detailed Description

The present invention is based on the finding that a photonic methodology using

thermochromics may be used to provide the simultaneous measurement of temperature and depth of a periodontal pocket. Accordingly, the present invention relates to an optical periodontal probe comprising a thermochromic material for measuring depth and/or temperature of a periodontal pocket. Also provided are methods of measuring depth and/or temperature of a periodontal docket wherein temperature of the periodontal pocket is determined from the spectrum of light returning to the detection means from the probe tip; and wherein the depth of the periodontal pocket is determined from the wavelength dependent intensities returning from the probe tip.

The periodontal probe comprises a handle and an optically transmissive probe tip. The handle comprises one or multiple light sources for illuminating the probe tip and a detection means for detecting wavelength dependence and intensity of light reflected from the probe tip. The probe tip comprises thermochromic material and a optically transmissive solid carrier material.

Insertion of the probe tip into a periodontal pocket causes the thermochromic material in the portion of the probe tip inserted into the periodontal pocket to change colour in a temperature dependent manner. In particular, in certain embodiments thermochromic material is a first colour or colourless below a threshold temperature (T_on) and as temperature is increased, pass through a series of colours until a maximum temperature is reached and a particular colour is maintained or transparency restored. In specific embodiments, the thermochromic material is colorless below a first threshold temperature (T_on), change in colour over a 8°C temperature range, and maintain a blue hue when above the maximum temperature detectable T_sat = T_on +8°C). In specific embodiments, the T_on= 32°C and T_sat = 40°C.

Accordingly, the temperature of the periodontal pocket may be determined from the wavelength of light (spectrum or selective probing wavelengths) reflected back to the detection means from the probe tip. The portion of the probe within the periodontal pocket is warmed above threshold temperature by the contact with the tissue and tooth and be coloured. The portion of the probe outside the pocket will be below threshold temperature and will be colourless. Accordingly, the intensity of a particular range of wavelengths of light reflecting to the detection means from the probe tip may be used to determine periodontal pocket depth.

In certain embodiments, the probe measures temperature (the average temperature of the tissue in contact with the probe) to an accuracy of 0.5°C. In certain embodiments, the probe measures temperature to a resolution of 0.2°C. In certain embodiments, the probe is able to perform a full periodontal exam without performance loss in temperature measurements. In certain embodiments, the probe requires no more than 1 second to perform a temperature measurement. In certain embodiments, the probe measures temperature at least 10 times per second. In certain embodiments, the probe measures temperature 100 times per second.

Depth can also be monitored using the probe. The portion of the probe within the pocket will be warmed above T_on by the contact with the tissue and be activated (coloured). The portion of the probe outside the pocket will be below T_on and will be transparent. The volume of interaction between the light and the activated TC is the volume within the gum pocket. A shallow pocket will result in a small interaction volume (less signal) and a deep pocket a larger interaction volume (more signal). The pocket depth is in this way encoded in the signal intensity.

Accordingly, the present invention provides a method of measuring periodontal pocket depth and/or temperature using a photonic periodontal probe comprising: a handle and an optically transmissive probe tip; the handle comprising a light source for illuminating said probe tip and a detection means for detecting spectrum and intensity of light reflected from said probe tip; the probe tip having a proximal end connected to the handle and an opposite distal end for insertion into the periodontal pocket; and the probe tip having thermochromic material and a solid carrier material, wherein temperature of said periodontal pocket is determined from the wave length dependence reflected back to the detection means from the probe tip; and wherein the depth of the periodontal pocket is determined from the intensity of light reflected back to the detection means from probe tip. In certain embodiments, the probe measures pocket depth (the length of the tissue in contact with the probe) with an accuracy of 0.25mm. In certain embodiments, the probe measures pocket depth with a resolution of 0.2mm. In certain embodiments, the probe is able to perform a full periodontal exam without performance loss in depth measurements. In specific embodiments, the pocket depth measurement is the length of the probe tip that is in contact with gingival tissue when the end of the probe tip is in contact with the bottom of the pocket and with a pressure of 16g is applied. In certain embodiments, for a tip end of 0.5mm diameter the force targeted is 20 to 25g.

In certain embodiments, the probe monitors application pressure during periodontal probing. In certain embodiments, the probe monitors application pressure during periodontal probing to an accuracy of 0.5g. In certain embodiments, the probe monitors application pressure during periodontal probing to a resolution of 1 .0g. In certain embodiments, the probe monitors application pressure during periodontal probing to a resolution of 2.5g. In certain embodiments, the probe provides applied pressure feedback in real time.

In certain embodiments, the probe simultaneous measures of temperature and pocket depth for each site probed. In certain embodiments, the amount of time required by the probe for simultaneous measurement of temperature and pocket depth is, on average no greater than the time required for conventional probes to measure depth alone. Periodontal probing of a site using a conventional probe takes an experienced clinician < 1 second. In certain embodiments, temperature measurements shall be representative of the average temperature of the gingival tissue in contact with the probe during a valid pocket depth measurement. In another embodiment the temperature measured will be the bottom of the pocket.

The probe may be wired, wireless or both. In certain embodiments, the probe transmits data wireless to a receiver. In certain embodiments, the probe continuously monitors and transmits data from data input.

Probe Tip

In certain embodiments the probe tip is disposable. In other embodiments, the probe tip is reusable. In reusable embodiments, the probe tips can be sterilized after each use. In certain embodiments, the probe tip is at least as comfortable to the patient as conventional probes and does not increase risk to the patient (infection, allergic response, tissue damage, debris from tip).

The probe tip comprises a thermochromic material and a solid carrier material. The thermochromic material may be coated on the carrier material or embedded in the carrier material. In certain embodiments, the thermochromic material is embedded in the carrier material. A worker skilled in the art would readily appreciate that the materials must be suitable for use in dental instruments. For example, a worker skilled in the art would readily appreciate that the materials used should produce a probe tip which maintains rigidity (no change in shape with pressure) during measurement, and has good resistance to breakage to ensure patient safety. In specific embodiments, the probe tips have <0.5mm deviation under 20g axial pressure.

The carrier material for use in the probe tip must be compatible with the thermochromic material (i.e. does not inhibit the thermochromic properties of the thermochromic material or prevent detection of a thermochromic change). In certain embodiments, the material is an optically transparent material. In specific embodiments, the material has at least 90% optical transparency. In certain embodiments, the carrier material is moldable. In certain embodiments, the carrier material is a polymer. In certain embodiments, the polymer is curable. In certain embodiments, the polymer is air curable. In other embodiments, the polymer requires the addition of an additive for curing. The additive may be a chemical additive, light, including but not limited to UV, visible and NIR light, or heat. In certain embodiments, a chemical additive is used. The polymer may be a thermoplastic or a thermoset polymer. In certain embodiments, the polymer is an acrylate polymer (also known as aryclics or polyacrylates), such as polymethyl methacrylate (PMMA). In certain embodiments, the polymer is a polyurethane. Appropriate polymers are commercially available, for example, the polyurethane PT8925 from PTM&W Products. For exemplary commercially available polymers include WC-780-AB; WC781 -AB; WC-782-AB; WC-783-AB; WC-784-AB; WC-786-AB; WC-788-AB; and WC-792-AB available from BJB Enterprises; Crystal Cast 1000, 2000, 3000, and 4000 from Alchemie and Water Clear Polyurethane Casting Resin from Easy Composites

The thermochromic material for use in the probe tip is a reversible thermochromic material which changes colour over a physiological temperature range. Non-limiting exemplary temperature ranges include but are not limited to 20°C to 50°C, 22°C to 40°C , 32°C to 40°C, 35°C to 40°C and 35°C to 40°C. In specific embodiments, the temperature range of the thermochromic material is 32°C to 40°C. Accordingly, in certain embodiments, the T_on is 32°C and the T_max is 40°C.

The thermochromic material may be in the form of a coating on the carrier material or may be embedded in the carrier material. In specific embodiments in which the thermochromic material forms a coating, the probe tip may be a hollow structure in which the thermochromic material is on the internal surface. In specific embodiments in which the thermochromic material forms a coating, the thermochromic material forms a coating on the outside of the probe tip. The thermochromic material may also be embedded in the carrier material.

Accordingly, in certain embodiments the probe tip comprises thermochromic material embedded in the carrier material.

Thermochromic materials may be in the form of liquid crystals or thermochromic liquid crystals or Leuco Dyes. In certain embodiments, the probe tip comprises thermochromic liquid crystals. Microencapsulation is known in the art as a means to stabilize and package liquid crystal and leuco dyes. In certain embodiments, the thermochromic material is thermochromic microcapsules. In specific embodiments, the thermochromic material is thermochromic liquid crystal microcapsules. Thermochromic materials, including but not limited to thermochromic liquid crystal microcapsules, are commercially available. For example, microencapsulated TLC slurries are available from LCR Hallcrest.

The concentration of thermochromic material should be sufficient to quantify the depth but not too high that the light only interacts with a portion of the thermochromic material. The concentration of thermochromic material must be less than 20% of the total material by weight. In certain embodiments, the concentration is between 1 % and 20%. In other embodiments, the concentration is between 5% and 15%. In further embodiments, the concentration is between 7% and 12%. In other embodiments, the concentration is about 1 %, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 1 1 %, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, or about 19%. In certain embodiments, the concentration is 10%.

In specific embodiments, the thermochromic materials are microencapsulated TLC slurries with a Ton of 32 °C and a bandwidth of 8 °C.

A worker skilled in the art could readily produce and test appropriate mixtures of

thermochromic material and carrier material for use as the probe tip. In specific

embodiments, the thermochromic materials are the microencapsulated TLC slurries from LCR Hallcrest with a red start of 32 °C and a bandwidth of 8 °C. In specific embodiments, the mixture is produced as follows: Mix the chiral nematic liquid crystals with the B2 polyurethane hardener in a plastic container with a metal mixing instrument for 4

minutes. Add the A polyurethane resin in the ratio of 1 A:0.6B by weight. Mix for 3 minutes. Degas the mixture for 4 minutes using a two-stage, 6 cubic feet per minute vacuum pump that can create a vacuum of at least -0.98 atmospheres. Pour or inject the material into the mold. Allow it to cure at room temperature. In certain embodiments, the TLC slurry is allowed to dry (desiccated) and ground to a fine powder which is then added to the carrier material A worker skilled in the art would readily determine appropriate thickness, length and geometry of the probe tip. In certain embodiments the probe tip is less than < 1 mm in thickness and at least 10mm in length. The probe tip may have various cross sectional shapes including but not limited to circular, oval, concave or convex.

Probe Handle

Also provided is a probe handle. The probe handle comprises a zone for reversible attachment of the probe tip, a transition zone and a handle zone. The probe handle comprises one or more light sources for illuminating the probe tip and a detection means for detecting spectrum and intensity of light reflected from said probe tip. The one or more light sources may be one or more broadband light sources, one or more light sources with selective wavelength emissions, or a combination thereof. The detection means may be a wavelength sensitive detector, such as a spectrometer or a detector that does not resolve wavelengths.

The probe handle may further comprise a means for pressure sensing. In certain

embodiments, the probe handle is capable of providing user feedback for low, acceptable and high pressures. In specific embodiments, the pressure sensor has an accuracy of 0.5g when used in a human population.

In certain embodiments, the probe handle comprises an internal power source which is optionally rechargeable. In specific embodiments, the charge lasts for 5 full periodontal exams. In certain embodiments, if the probe is operated with at least 15 minutes between each periodontal exam and power is provided during this 15 minute period, the probe can operate without down time for a full clinical day.

In certain embodiments, the probe handle transmits data wirelessly. In specific embodiments, the probe handle transmits all clinical and ancillary measurements / information over a wireless transmission interface to be permanently recorded in a digital chart. In specific embodiments, no information is lost during transmission over distances of up to 30’ with no wall between the receiver and the probe handle.

In specific embodiments, the probe handle manages all functions related to the photonics signals to and from the probe tip, including the photonic / optical components; manages the pressure monitoring system and provide feedback to the user; digitizes all analog signals required to perform the depth and temperature measurements as per the probe tip requirements; relates all information to be recorded wirelessly to a remotely connected device and operates without tethering to any other device during a periodontal exam. As the probe handle is reusable, a method of sterilizing the probe handle is also provided.

Examples

The purpose of the experiment was to analyse, both qualitatively and quantitatively, the response of thermochromics (encased in polyurethane samples) to a change in temperature (22.0^°C to 40.0^°C). This analysis was conducted by measuring the spectra emitted by the inactivated and activated thermochromics. Thermochromics are inactivated below 32.0^°C and are activated between 32.0^°C - 40.0^°C. For our experiments, the spectra intensities of the thermochromic samples at 22.0^°C were the inactivated intensities.

The thermochromic spectra intensities were measured by quantifying the amount of incident white light reflected off the surface of the thermochromic sample. First, the maximum reflection of the white light is characterised by measuring the reflection against a white opal disk, which is representative of total reflection. This maximum reflection is known as the white light intensities, which were used to normalise the measured intensities of the samples. Second, the thermochromic samples were placed on a black absorbing disk then on the sample measurement site. The sample is heated up and the activated thermochromic response is located by moving the sample around under the incident white light fibre until the expected spectrum is observed. Once the thermochromic response has been identified at a location, x, on the sample surface, the spectra intensity at x is measured while cooling and heating the sample. The corresponding wavelengths and temperatures were recorded. Note that the spectra intensities were measured under a black cloth to avoid any contribution of ambient light to the measured data, hence minimizing experimental errors.

DATA ANALYSIS FOR WAVELENGTH SELECTION

Measured intensity change versus wavelength:

Using SpectraSuite software, the spectra intensities of the sample were collected while heating (from 22.0^°C to 40.0^°C) and cooling (from 40.0^°C to 22.0^°C) the sample. In

SigmaPlot 1 1 .0, the excel file Spectra Suite Data Summary. xls were imported. The raw data was graphed, that is, measured intensities against the wavelength range.

Figure 4 illustrates measured intensity change versus wavelength during sample cooling. Figure 5 illustrates measured intensity change versus wavelength during sample heating. Note: Intensity measurements collected while heating or cooling the sample is denoted by FI/C at the end of the graph title. For example, S35C is representative of intensities measured while cooling Sample 35.

Normalised intensity change versus wavelength

The following Import White Light and Graph_C02 macro was used normalise the measured intensities. The normalised intensities were graphed against their corresponding wavelength ranges.

Macro: Import White Light and Graph_C02

1 . Imports white light intensities on the worksheet containing the raw intensity data.

2. Calls the Normalisation Transform transform;

a. The inactivated intensities (intensities at 22V) were subtracted from the raw data intensities.

b. The resulting intensities were divided by the white light intensities to produce the normalised intensities.

3. Plots a graph of normalised intensities against the wavelength range.

Figure 6 illustrates normalised intensity change versus wavelength during sample cooling. Figure 7 illustrates normalised intensity change versus wavelength during sample heating.

Normalised intensity change versus temperature

Using the following Transpose Normalised Intensities and Graph COvl macro, intensities corresponding to the wavelengths from 350 nm - 800 nm (in 10 nm steps, that is, 350 nm,

360 nm, ..., 800 nm) were selected. The selected intensities were transposed and the transposed intensities were graphed against the temperature range, 22.0^°C - 40.0^°C.

Macro: Transpose Normalised Intensities and Graph COvl

1. Calls the Select Rows transform;

a. Selects the normalised intensities for wavelengths ranging from 350 nm - 800 nm (in 10 nm steps).

2. Transposes the selected wavelength intensities.

3. Plots a graph of the transposed wavelength intensities against the temperature range, 22.0V to 40.0V.

Figure 8 illustrates normalised intensity change versus temperature during sample cooling. Figure 9 illustrates normalised intensity change versus temperature during sample heating. Binned intensity change versus temperature

Using the following Bin lntensities_COv1 macro (see Appendix C, Section C), the transposed intensities (in 50 nm ranges) were binned (averaged). The binned intensities were graphed against the temperature range.

Macro: Bin lntensities_COv1

Methodology

1. Calls the Binning Transform vl transform;

a. Bins (averages) the previously selected wavelength intensities in every 50 nm range, that is, 350 nm - 400 nm, 410 nm - 450 nm..., 760 nm - 800 nm

2. Plots a graph of the binned intensities against the temperature range, 22.0^° C to

40.0^°C

Figure 10 illustrates binned intensity change versus temperature during sample cooling. Figure 1 1 illustrates binned intensity change versus temperature during sample heating.

The above steps were repeated for all repeated experiments of the sample. From the analysis, the selected wavelength ranges of interest were 510 - 550 nm, 560 - 600 nm, and 510 - 650 nm. The intensities of the selected wavelength ranges of each repeated sample experiment were compared. That is, compare 510 - 550 nm intensities of S35Run1 C to 510 - 550 nm intensities of S35Run2C, and so forth for all repeated experiments. The multiple sample runs were graphed on the same plot to compare. Figure 12 illustrates binned intensity versus temperature during sample cooling. Figure 13 illustrates binned intensity change versus temperature during sample heating.

Absolute intensity ratio versus temperature

For each repeated sample experiment, the Wavelength Ratio Transform was used to calculate the absolute ratios of the selected wavelength ranges to each other. The absolute ratios of each repeated sample experiment were graphed against the temperature range and compare.

Transform: Wavelength Ratio Transform

1. Calculates the following absolute ratios of the selected wavelength range (510 - 550 nm, 560 - 600 nm, 610 - 650 nm, and 660 - 700 nm) for each repeated sample experiment data:

a. abs((560 - 600 nm)/ (510 - 550 nm))

b. abs((610 - 650 nm)/ (510 - 550 nm))

c. abs((660 - 700 nm)/ (510 - 550 nm)) where abs is the absolute value of the wavelength intensities

Figure 14 illustrates absolute intensity ratio versus temperature during sample cooling. Figure 15 illustrates absolute intensity ratios versus temperature during sample heating.

Mean and standard deviation of absolute ratios

Using the Mean Std dev Std error transform the mean, standard deviation, and standard error of the absolute ratios of the sample experiment repetitions were calculated. The mean and standard deviation were graphed, as error bars, against the temperature range, 32.0^°C to 36.0^°C.

Transform: Mean Std dev Std error

Methodology

1 . Rearranges the absolute ratios of the multiple data sets (due to repeated sample experiments) in the data sheet.

2. Calculates the mean, standard deviation and standard error of the multiple data sets per absolute ratio. For example, calculates the mean, standard deviation and standard error of abs((560 - 600 nm)/(510 - 550 nm)) ratios for all the repeated data sets.

Figure 16 illustrates mean and standard deviation of absolute ratios during sample cooling. Figure 17 illustrates mean and standard deviation of absolute ratios during sample heating.

Based on sample analysis, the selected wavelengths of interest were 510 nm, 560 nm, and 610 nm

DATA ANALYSIS FOR TEMPERATURE CALIBRATION ALGORITHM

Binned intensity change versus temperature

Using SpectraSuite, the wavelength intensities of the sample were measured while heating (from 22^°C to 40^°C) and cooling (from 40^°C to 22^°C). This was assigned as the Calibration data. After 90 minutes, the experiment was repeated, this was assigned as the Measured data. In SigmaPlot 1 1 .0, the excel file, Temperature vs Wavelength Experiment Summary.xls was imported. The Temperature Calibration Binning CO macro was used to bin (average) the wavelengths of interest: 510 nm, 560 nm and 610 nm (± 5 nm). The binned intensities were graphed against the temperature range, 22.0^°C - 40.0^°C. The steps were repeated for the Measured data. Figure 18 illustrates binned intensity change versus temperature during sample cooling. Figure 19 illustrates binned intensity change versus temperature during sample heating.

Calibration and Measured intensity

The Sum of Squares macro was used calculate the sum of squares of the Calibration and Measured intensities. The resulting minima plots were graphed for each half temperature from 22^°C - 40^°C, that is, 22.0^°C, 22.5^°C, 40.0^°C

T ran storm : Sum of Squares

1 . Calculates the Sum of Squares of the Calibration and Measured intensities

corresponding to the selected wavelengths (510 nm, 560 nm, and 650 nm).

a. Calculates the Sum of Squares for each temperature using the equation below:

x(T), y(T), and z(T) are intensities of wavelengths 510 nm, 560 nm, and 650 nm

Figure 20 illustrates calibration and measured intensity change during sample cooling.

Figure 21 illustrates calibration and measured intensity change during sample heating.

Figure 22 illustrates error graphs showing respective temperature minima during cooling. Figure 23 illustrates error graphs showing respective temperature minima during heating.

Example 2

The same optical setup was used as temperature generally, monitor the plotted wavelengths which have been selected for optimize temperature measurements.

A sample (cylindrical) approximately 200 mm in length that have a length of clear plastic and a length with the TLC (the 3, 6, and 9 mm values) and monitor the change in intensity at a fixed temperature (40 deg. C) for each sample was created. Repeat 3 times and average, that is the plot In these samples the change in intensity is linear, we do not expect this to be maintained in the probe tips as they are not perfectly cylindrical but more conic in shape (see figure 30)

PRINCIPAL COMPONENT ANALYSIS (PC A) DATA FOR TEMPERATURE CALIBRATION ALGORITHM

1. SpectraSuite was used to measure the wavelength intensities of the sample while heating (from 22^°C to 40^°C) and cooling (from 40^°C to 22^°C). This was assigned as the Calibration data

a. After 90 minutes, repeat the experiment, this is assigned as the Measured data

2. In SigmaPlot 1 1 .0, the excel file, Spectra Suite Data Summary.xls was imported

3. Using the Normalisation Transform vl .xfm transform

4. Transposed the normalised data

5. Using Mathcad 14, imported the transposed normalised data

6. Ran the SMean(A) (see below) and Vari(A,savg) (see below) functions to calculate the variance of the normalised data

7. In Mathcad 14, performed PCA analysis by running resulting variance through the singular value decomposition function (svd2) on the resulting variance data

8. In SigmaPlot 1 1 .0, copied and transposed the right singular vectors, V^H, from the singular value decomposition

9. Repeated steps 2 - 8 for the Measured data

10. On a single plot, graph the first three transposed Calibration and Measured V^H and compare

11 . If the Calibration and Measured V^H traces are out of phase, multiply the Measured V^H by -1 . Plot Calibration and (-1 x Measured) V^H and compare

12. Using the Sum of Squares macro (see Appendix C, Section G), the sum of squares of the Calibration and Measured V^H values was calculated.

13. The resulting minima plots for each half temperature from 22^°C - 40^°C, that is,

22.0^°C, 22.5^°C, ..., 40.0^°C were graphed

Function: SMean(A)

Methodology

1. Calculates the mean of each temperature’s intensities across the wavelength range. a. A is an nxm matrix

b. savg is the resulting mean nx1 matrix SMean(A) d - A

rd <— rows (d)

cd <— cols(d)

for j s 0.. cd - 1

savg <- e

savg

Function: Vari(A, savg )

Methodology

1. Calculates the variance of each wavelength’s intensities by subtracting the mean value, savg, from the normalised intensities

a. A is an nxm matrix

b. savg is the resulting mean nx1 matrix

c. Vari A is the resulting nxm matrix

Vari(A . savg) ra ·*— rows (A)

ca <— cols(A)

for i e 0 ra - 1

VariA

Figure 31 illustrates calibration and measured right singular vectors during sample heating. Figure 32 illustrates calibration and measured right singular vectors during sample heating. Figure 33 illustrates error graphs showing respective temperature minima, 30.0 - 30.5.

Figure 34 illustrates error graphs showing respective temperature minima, 33.0 - 33.5.

Claims

Claims:

1 . A photonic periodontal probe for measuring depth and/or temperature of a periodontal pocket, the periodontal probe comprising:

a handle and an optically transmissive probe tip;

said handle comprising one or more light sources for illuminating said probe tip and a detection means for detecting spectrum and intensity of light reflected from said probe tip; said probe tip having a proximal end connected to the handle and an opposite distal end for insertion into the periodontal pocket; and

said probe tip having thermochromic material and a solid carrier material,

wherein temperature of said periodontal pocket is determined from the wave length dependence reflected back to the detection means from the probe tip; and

wherein the depth of the periodontal pocket is determined from the intensity of light reflected back to the detection means from probe tip.

2. The photonic periodontal probe of claim 1 , wherein said one or more light sources are one or more broadband light sources, one or more light sources with selective wavelength emissions, or a combination thereof.

3. The photonic periodontal probe of claim 1 or 2, wherein the detection means is a wavelength sensitive detector.

4. The photonic periodontal probe of claim 3, wherein said detection means is a

spectrometer.

5. The photonic periodontal probe of claim 1 or 2, wherein the detector does not resolve wavelength.