Detecting the distance of a probe to the pulp of a tooth

Abstract

A method and apparatus for detecting a distance of a probe contacting a tooth surface to a pulp of a tooth by determining an indication of a thickness of a dentin of the tooth is provided. The method includes illuminating tooth tissue of the tooth with the probe and then receiving data indicative of scattered light from the tooth tissue. A spectrum of the scattered light is then acquired and analyzed to further acquire a spectral analysis result. An indication of the thickness of the dentin of the tooth is then determined based on the spectral analysis result. The method can help prevent accidental exposure of the pulp during dental treatments such as drilling.

Description

Technical Field

[0001] This invention relates to the field of oral treatment, and more specifically to a concept for detecting the distance from a probe to the dental pulp of a tooth. Background Technology

[0002] The dental pulp resides in a rigid chamber within the oral cavity (i.e., the tooth), which comprises dentin, enamel, and cementum. It serves several fundamental functions: increasing the tooth's resistance to bacterial invasion; acting as a warning mechanism due to its sensitivity to thermal and mechanical stimuli; and providing a force feedback loop to the masticatory muscles. However, the integrity of the dental pulp can be compromised by cavities or dental procedures required to remove cavities, such as drilling. Therefore, the ability to measure the distance to the pulp within the range of 2 mm to 0.2 mm is crucial for preventing pulp damage during dental surgery or for selecting the appropriate treatment for previously damaged pulp.

[0003] Although treating dental caries is a simple and common procedure, 29% of deep caries treatments result in accidental pulp exposure. To fix the exposed pulp, root canal treatment is necessary, but this is much more time-consuming and expensive than the initial caries treatment. Therefore, avoiding accidental pulp exposure has significant benefits.

[0004] Stepwise aspiration can reduce the likelihood of unintended pulp exposure from 29% to 18%. However, during the removal of temporary fillings or final excision, stepwise aspiration may simultaneously lead to additional patient discomfort, increased costs, and an increased risk of pulp exposure. Furthermore, treatment with stepwise excision requires multiple appointments, thus increasing the risk of treatment failure (e.g., because the patient does not return to the dentist to complete the treatment). Therefore, stepwise excision is not considered a suitable long-term solution.

[0005] Currently, the methods used to measure the distance to the dental pulp are primarily subjective: the dentist applies his / her experience and knowledge of dental anatomy to the visual appearance of the tooth. Objective measurement methods include X-ray imaging, but this utilizes harmful ionizing radiation and provides a limited view of the tooth.

[0006] US 2009 / 0155735 discloses a dental device including a white light interferometer for determining the distance from its surface to the dental pulp of the tooth. Summary of the Invention

[0007] This invention is defined by the claims.

[0008] According to one aspect of the present invention, a method for detecting the distance from a probe to the dental pulp of a tooth by determining an indication of the thickness of the dentin of the tooth is provided, as claimed in claim 1.

[0009] The proposed embodiment can detect the distance from a probe in contact with the tooth surface to the dental pulp by irradiating the tooth tissue. According to the proposed concept, data representing scattered light from the irradiated tooth tissue can be received and used to acquire the spectrum of the scattered light. By analyzing the spectrum, the distance from the tooth surface to the dental pulp can be inferred. In this way, a safe, objective, and accurate measurement of the distance to the dental pulp can be achieved. For example, the proposed embodiment can be used during dental treatments to prevent accidental pulp exposure, particularly in treatments involving drilling (such as caries treatment).

[0010] In particular, it has been recognized that the properties of the visible light spectrum reflected or scattered by the dentin of teeth can be used to detect the presence of blood (in the dental pulp) behind dentin that is up to 2 mm thick.

[0011] Studies have shown that when the probe is close to the dental pulp, the absorption spectrum of blood can be high in the 500nm to 600nm wavelength range. Further research indicates that the blood absorption spectrum can exhibit two absorption peaks: one near 540nm and a second near 580nm. The reflectance spectrum of visible light reflected or scattered by dentin was also investigated, and this spectrum shows troughs at 540nm and 580nm, indicating that the proportion of visible light reflected from dentin decreases at these wavelengths. It has been proposed that visible light is absorbed by the blood in the dental pulp. Therefore, the absorption spectrum of the blood contained in the dental pulp can be correlated with the reflectance spectrum of visible light reflected / scattered by the dentin.

[0012] The study also observed that reflectance decreased when dentin thickness was 1 mm within the 400 nm to 600 nm range. The study indicates that dentin thicknesses within a comparable range (i.e., 0–2 mm) exhibit similar reflectance spectra.

[0013] At a relatively thin dentin thickness (i.e., 0-2 mm), visible light from the probe can penetrate the dentin to reach the blood in the dental pulp. Blood absorbs substantially more light than dentin, particularly noticeable in the 400 nm to 600 nm wavelength range due to the presence of blood absorption peaks. Visible light is absorbed by both blood and dentin, thus increasing visible light absorption. Consequently, a smaller proportion of the light can be reflected back to the probe.

[0014] At thicker dentin thicknesses (i.e., greater than 2 mm), visible light may not penetrate the dentin to reach the blood vessels in the pulp. Because dentin absorbs a lower proportion of visible light compared to the aforementioned combination of blood and dentin, the proportion of light reflected from the dentin increases. The 2 mm threshold dentin thickness used in the preceding scenario is merely an example and can vary (e.g., within the range of 1.5 mm to 2.5 mm).

[0015] To further investigate, the amplitude of the spectrum in the 400 nm to 600 nm range was integrated and plotted together with a dentin thickness of less than approximately 2 mm. The integrated amplitude of the spectrum decreased as the dentin thickness decreased, indicating that the variable can be proportional.

[0016] By utilizing these findings, it is proposed that the spectrum and integrated amplitude of visible light reflected / scattered by teeth can be used to determine dentin thickness (and thus provide an indication of the distance from the dentin to the pulp). Specifically, dentin thickness can be determined within three distinct ranges:

[0017] (i) If the integral amplitude of the spectrum in the range of 400 nm to 600 nm exceeds the threshold and the spectrum does not show a reflectance trough (i.e., a light absorption peak), it can be determined that no light reaches the blood, because all the light is reflected by the dentin. It can then be inferred that the thickness of the dentin is in the range of approximately 2 mm to approximately 1 mm;

[0018] (ii) If the integral amplitude of the spectrum in the 400 nm to 600 nm range is below a threshold, and the spectrum shows a reflectance trough (i.e., a light absorption peak), it can be determined that light is only partially reflected by the dentin and reaches the blood. It can then be inferred that the dentin thickness is in the range of approximately 1 mm to approximately 0.2 mm; and

[0019] (iii) If the integral amplitude of the spectrum in the range of 400 nm to 600 nm is below the threshold and the spectrum does not show reflectance troughs (i.e., light absorption peaks), it can be determined that all light is absorbed by the blood and no light is reflected by the dentin. Therefore, the thickness of the dentin is less than about 0.2 mm, although this value can vary.

[0020] However, it should be understood that the aforementioned distances can vary. For example, the 2mm threshold detailed above can range from 1.75mm to 2.25mm. As another example, the clinical variation in the thresholds detailed above (i.e., 0.2mm, 1mm, and 2mm) can range from 10% to 30%.

[0021] Conventional methods for determining the distance from the treatment point to the dental pulp are mostly subjective and rely on the dentist's experience. Specifically, dentists must apply their knowledge of dental anatomy to the visual appearance of the teeth. However, reliance on subjectivity can increase the risk of human error. Furthermore, this risk is amplified if the dentist lacks sufficient experience. Using the proposed embodiment, dentists can benefit from an objective measurement method that limits the risk of human error.

[0022] According to the proposed embodiments, dentists can benefit from an objective measurement of the distance from the dental probe contacting the tooth surface to the surface pulp, which not only contains significantly more information than X-ray imaging but also eliminates the need for harmful radiation. Furthermore, comparisons between subjects (e.g., patients) can be facilitated by obtaining a single measurement indication or metric (e.g., an indication of the thickness of the dentin between the probe in contact with the tooth and the pulp).

[0023] The proposed embodiments can also significantly reduce the occurrence of unintended pulp exposure, thereby saving dentists time and money.

[0024] By providing a robust method for determining the distance from the tooth surface to the dental pulp, the embodiments can replace the use of stepwise excavation.

[0025] Other embodiments can obtain spectral analysis results from the spectrum by determining the slope of the intensity of the spectrum in the 300-800 nm range, and thus the determined intensity slope can be used to determine an indication of the dentin thickness of the tooth. Using the determined intensity slope, the thickness of the dentin between the probe (in contact with the tooth surface) and the dental pulp of the tooth can be determined more reliably.

[0026] Furthermore, the embodiments can obtain spectral analysis results from the spectrum by detecting light absorption peaks, the wavelength range of which characterizes the wavelength range of the light absorption spectrum of blood. Therefore, the detected light absorption peaks can be used to determine an indication of the distance from the tooth contact probe to the dental pulp. Using the detected light absorption peaks, an indication of the dentin thickness between the probe (in contact with the tooth surface) and the dental pulp can be determined more accurately.

[0027] The embodiments can utilize the wavelength ranges of the blood's light absorption spectrum, specifically 520-550 nm and 570-590 nm. By limiting the wavelength range, the detection of light absorption peaks can be made more efficient.

[0028] A computer program product may include a computer program code means that, when executed on a computing device having a processing system, causes the processing system to perform a previously interpreted method for detecting the distance from a probe to the dental pulp of a tooth.

[0029] In other embodiments, a method for preventing exposure of the dental pulp of a subject's tooth during dental treatment may include irradiating the tooth tissue of the subject's tooth with broadband visible light and detecting the visible light reflected from the tooth tissue. The method for preventing exposure of the dental pulp of a subject's tooth may further include analyzing the spectrum of the detected visible light reflected from the tooth tissue to obtain spectral analysis results, and also generating an indication of the distance to the dental pulp of the subject's tooth (e.g., an indication of the thickness of the dentin between the probe in tooth contact and the dental pulp) based on the spectral analysis results.

[0030] Furthermore, embodiments may include a method for analyzing the spectrum of detected visible light reflected from tooth tissue. This method may include determining the intensity of the detected visible light spectrum in the range of 400-800 nm.

[0031] Furthermore, this method can analyze the variation of the amplitude of detected visible light with respect to wavelength to detect light absorption peaks in the 400-800 nm range. The method may also include determining spectral analysis results based on the intensity of the determined spectrum and the detection results.

[0032] An embodiment may utilize a method that analyzes the variation of the amplitude of detected visible light relative to its wavelength to detect light absorption peaks in the 300-800 nm range using the following procedure. The light absorption peaks in the 300-800 nm range can be detected by observing the first and second troughs in the amplitude variations of the detected visible light in the 520-550 nm and 570-590 nm ranges, respectively. Preferably, the first and second troughs in the amplitude variations of the detected visible light can be observed at 540 nm and 580 nm, respectively.

[0033] Other embodiments may include a method in which determining the intensity of the detected visible light spectrum in the 300-800 nm range includes performing an integration operation.

[0034] Furthermore, the method for determining the spectral analysis can include the following procedures: In response to a determined intensity exceeding a threshold and no light absorption peak being detected, the distance to the dental pulp of the subject's tooth within the range of 1-2 mm can be determined as the spectral analysis result. Furthermore, in response to a determined intensity not exceeding a threshold and a light absorption peak being detected, the distance to the dental pulp of the subject's tooth within the range of 0.2-1 mm can be determined as the spectral analysis result. Finally, in response to a determined intensity not exceeding a threshold and no light absorption peak being detected, the distance to the dental pulp of the subject's tooth less than 0.2 mm can be determined as the spectral analysis result.

[0035] A computer program product may include a computer program code means that, when executed on a computing device having a processing system, causes the processing system to perform a previously explained method for determining the distance from a probe to the dental pulp of a tooth by determining the thickness of the dentin of the tooth.

[0036] Furthermore, embodiments may include a dental device according to claim 6 for determining the distance from a probe to the dental pulp of a tooth by determining the thickness of the dentin of the tooth.

[0037] Furthermore, the embodiments can obtain spectral analysis results from the spectrum by determining the intensity of the spectrum in the 300-800 nm range. By determining only the intensity within a specific range, the processor can execute its functions more quickly.

[0038] The embodiment can obtain spectral analysis results from the spectrum by detecting light absorption peaks, the wavelength range of which characterizes the wavelength range of the blood's absorption spectrum. By following the above process, blood absorption peaks can be identified, thereby enabling more accurate detection of the distance to the dental pulp.

[0039] Other embodiments can use the wavelength ranges of the blood absorption spectrum, namely 520-550 nm and 570-590 nm. Therefore, absorption peaks can be identified more quickly.

[0040] The proposed embodiment can prevent exposure of the dental pulp of a subject's teeth during dental treatment using a device comprising a dental probe, a spectral analysis component, and a processor. In use, the dental probe can be configured to irradiate tooth tissue and detect visible light reflected from the tooth tissue. The spectral analysis component can then analyze the spectrum of the reflected light to produce a result, which the processor can use to generate an indication of the distance from the probe in contact with the tooth to the dental pulp of the subject's tooth. The indication can be visible, audible, vibratory, or other means including those involving human senses.

[0041] Other embodiments may employ the following concept, wherein the spectral analysis component is configured to follow the procedure below. Initially, the intensity of the detected visible light spectrum in the 300-800 nm range can be determined. Then, the variation of the amplitude of the detected visible light with respect to wavelength can be analyzed to detect light absorption peaks in the 300-800 nm range. Finally, the spectral analysis results can be determined based on the spectral intensity and the detection results. By following the above procedure, light absorption peaks can be identified, thereby enabling more accurate detection of the distance to the dental pulp.

[0042] The embodiment can configure the spectral analysis component to detect light absorption peaks in the 300-800 nm range by observing a first trough and a second trough in the amplitude variation of the detected visible light in the 520-550 nm and 570-590 nm ranges, respectively. Preferably, the first trough and the second trough in the amplitude variation of the detected visible light can be observed at 540 nm and 580 nm, respectively. Analyzing the amplitude variation of the detected visible light within a further limited range allows for faster identification of troughs, and thus enables faster determination of the indication of distance to the dental pulp (i.e., the thickness of dentin between the probe in contact with the tooth and the dental pulp).

[0043] The embodiment can also configure the spectral analysis component to determine the intensity of the detected visible light spectrum in the 300-800 nm range by performing an integration operation. Calculating the integral amplitude of the intensity spectrum allows for a more accurate determination of the distance from the dental pulp.

[0044] Furthermore, embodiments can employ the concept that the spectral analysis component is configured to determine a distance to the pulp of the subject's tooth within a 1-2 mm range as a spectral analysis result in response to a determined intensity exceeding a threshold and no light absorption peak being detected. The spectral analysis component can also be configured to determine a distance to the pulp of the subject's tooth within a 0.2-1 mm range as a spectral analysis result in response to a determined intensity not exceeding a threshold and no light absorption peak being detected. Additionally, the spectral analysis can be configured to determine a distance to the pulp of the subject's tooth less than 0.2 mm as a spectral analysis result in response to a determined intensity not exceeding a threshold and no light absorption peak being detected. Through a well-defined measurement area, the spectral analysis component can transmit significant distances from the pulp to the probe, such as 2 mm, 1 mm, and 0.2 mm. Therefore, when the probe measures in real time, it can indicate an alert mechanism to the dentist, allowing the dentist to know the approximate distance between the probe and the pulp.

[0045] In some embodiments, the dental probe may include an optical waveguide configured to receive broadband visible light and guide the received broadband visible light to a first emitting portion of the waveguide. In use, the waveguide may then be adapted to be positioned near the tooth tissue of a subject's teeth. The implementation of the optical waveguide allows for precise control of visible light exposure to the tooth tissue, thereby ensuring that the dentin is illuminated.

[0046] Other embodiments may further configure the optical waveguide to receive visible light reflected from the tooth tissue and guide the received visible light reflected from the tooth tissue to the spectral analysis component. Therefore, a single optical waveguide may be sufficient for both emitting visible light to the tooth tissue and detecting the light reflected from the subject's tooth tissue.

[0047] One embodiment may employ a concept in which the optical waveguide comprises an optical fiber and a beam splitter. Because the beam splitter allows both emitted and reflected visible light to occupy the same fiber, it enables the realization of a dental probe with a single optical fiber.

[0048] According to another aspect of the invention, a drill bit comprising a dental device according to the proposed embodiment is provided.

[0049] These and other aspects of the invention will become clear from the embodiments described below and will be set forth with reference to the embodiments described below. Attached Figure Description

[0050] To better understand the invention and to more clearly illustrate how to implement it, reference is now made to the accompanying drawings by way of example only, in which:

[0051] Figure 1 The absorption spectrum of blood is shown;

[0052] Figure 2 The reflectance spectrum measured on a 1 mm thick dentin slice is shown.

[0053] Figure 3 The reflectance spectra for a series of dentin thickness measurements are shown;

[0054] Figure 4 A comprehensive amplitude diagram for a range of dentin thicknesses is shown;

[0055] Figure 5 A method for preventing pulp exposure in a subject during dental treatment is shown;

[0056] Figure 6 The proposed method for preventing pulp exposure in a subject during dental drilling is shown;

[0057] Figure 7 An example of a computer in which one or more portions of an embodiment may be employed is shown;

[0058] Figure 8 A dental device for determining the distance from a probe to the dental pulp of a tooth is shown.

[0059] Figure 9 The proposed dental device for determining the distance from the probe to the dental pulp of a tooth is shown.

[0060] Figure 10 An embodiment of the proposed probe, comprising two optical fibers, is shown.

[0061] Figure 11 An embodiment of the proposed probe, including an optical fiber and a beam splitter, is shown.

[0062] Figure 12 An embodiment of a drill bit including a dental device is shown. Detailed Implementation

[0063] The invention will be described with reference to the accompanying drawings.

[0064] It should be understood that the detailed descriptions and specific examples, while indicating exemplary embodiments of the apparatuses, systems, and methods, are for illustrative purposes only and are not intended to limit the scope of the invention. These and other features, aspects, and advantages of the apparatuses, systems, and methods of the present invention will be better understood from the following description, the appended claims, and the accompanying drawings. The fact that certain measures are enumerated only in mutually different dependent claims does not imply that combinations of these measures cannot be used for advantageous purposes. It should be understood that these figures are merely schematic and not drawn to scale. It should also be understood that the same reference numerals are used in the drawings to indicate the same or similar parts.

[0065] Implementations according to this disclosure relate to various systems, adapters, and / or methods for indicating the distance from a tooth contact probe to the dental pulp, and to preventing pulp exposure during dental treatment. Based on the proposed concepts, numerous possible solutions can be implemented individually or in combination. That is, although these possible solutions may be described individually below, two or more of these possible solutions may be implemented in one or another combination.

[0066] The proposed embodiments provide a method for indicating the distance from a probe (in contact with the tooth) to the dental pulp. Therefore, the embodiments can be used to prevent unintentional pulp exposure. The embodiments utilize a dental probe to contact the tooth surface and irradiate the tooth tissue. Data representing scattered light from the tooth tissue is then received, and the spectrum of the scattered light is acquired. Spectral analysis results are then obtained from the spectrum, and the distance from the probe to the dental pulp is inferred based on the spectral analysis results.

[0067] In particular, it has been recognized that the spectral properties of visible light reflected or scattered by the dentin of teeth can be used to detect the presence of blood (which will be contained in the dental pulp) behind dentin thicknesses of up to 2 mm.

[0068] Studies have shown that the absorption spectrum of blood can be very high in the wavelength range of 500nm to 600nm, such as... Figure 1 As shown.

[0069] Figure 1 The absorption spectrum of blood 100 is shown, where the horizontal axis represents wavelength (nm) and the vertical axis represents millimolecular absorbance (L·mmol). -1 .cm -1Further research has shown that the absorption spectrum of blood can exhibit two absorption peaks: one at approximately 540 nm and the other at approximately 580 nm, making these peaks typically fall within the ranges of 520-550 nm and 570-590 nm. Figure 1 As shown, peak 101 appears at a wavelength of ~540 nm, and peak 102 appears on both sides of the ~580 nm wavelength. Therefore, Figure 1 This is consistent with the findings of the survey mentioned above.

[0070] The reflectance spectra of visible light reflected or scattered by dentin were also studied, and the reflectance spectra were as follows: Figure 2 As shown.

[0071] Figure 2 The reflectance spectrum 200 for a 1 mm thick dentin slice is shown, where the horizontal axis represents wavelength (nm) and the vertical axis represents reflectance (arbitrary units). Figure 2 Troughs in reflectance can be observed: trough 201 appears at ~540 nm, and the second trough 202 appears at ~580 nm. These reflectance troughs indicate that the proportion of visible light reflected from dentin decreases at these wavelengths. Furthermore, absorption peaks 101 and 102 appear at wavelengths very similar to the reflectance troughs 201 and 202, and reflectance also decreases in the 400 nm to 600 nm range, which is consistent with... Figure 1 The increased absorption shown is consistent with the increase in the 450 nm to 600 nm range. Therefore, it can be inferred that visible light is absorbed by the blood in the dental pulp. Thus, the absorption spectrum of the blood contained in the dental pulp can be correlated with the reflectance spectrum of visible light reflected / scattered by the dentin of the tooth, such that the absorption peaks correspond to the reflectance troughs.

[0072] The study also showed that dentin with a thickness of less than 2 mm exhibits reduced absorption and increased reflectivity in the 400 nm to 600 nm range, and these variables can be dependent.

[0073] Figure 3 The measured reflectance spectra 300 for a range of dentin thicknesses are shown, with the horizontal axis representing wavelength (nm) and the vertical axis representing reflectance (arbitrary units). Furthermore, the shading of lines 310, 312, and 314 indicates different dentin thicknesses, with 310 indicating high dentin thickness, 312 indicating medium dentin thickness, and 314 indicating low dentin thickness. Figure 3 It is evident that lower dentin thickness results in lower reflectivity. Furthermore, the spectral slopes 301 and 302 can help determine the distance to the dental pulp (i.e., dentin thickness).

[0074] For further research, Figure 3The amplitude of the spectrum (in the range of 400 nm to 600 nm) was integrated and plotted as a function of dentin thickness less than 2 mm, such as Figure 4 As shown.

[0075] Figure 4 An integral amplitude plot 400 is shown for a series of dentin thicknesses, where the horizontal axis represents the distance to the pulp (micrometers) and the vertical axis represents the integral amplitude (arbitrary units). As dentin thickness decreases, the integral amplitude of the spectrum also decreases, indicating that the variable can be proportional.

[0076] By utilizing these findings, it is proposed that the spectrum and integrated amplitude of visible light reflected / scattered by teeth can be used as an indicator to determine dentin thickness (and thus provide an indication of the distance from the tooth surface to the pulp). Specifically, dentin thickness can be determined within three distinct ranges:

[0077] (i) If the integral amplitude of the spectrum in the range of 400 nm to 600 nm exceeds the threshold and the spectrum does not show a reflectance trough (i.e., a light absorption peak), it can be determined that no light reaches the blood, because all the light is reflected by the dentin. Therefore, the thickness of the dentin is in the range of 2 mm to 1 mm.

[0078] (ii) If the integral amplitude of the spectrum in the range of 400 nm to 600 nm is below the threshold, and the spectrum shows a reflectance trough (i.e., a light absorption peak), it can be determined that light is only partially reflected by the dentin and reaches the blood. Therefore, the thickness of the dentin is in the range of 1 mm to 0.2 mm.

[0079] (iii) If the integral amplitude of the spectrum in the range of 400 nm to 600 nm is below the threshold and the spectrum does not show reflectance troughs (i.e., light absorption peaks), it can be determined that all light is absorbed by the blood and no light is reflected by the dentin. Therefore, the dentin thickness is less than 0.2 mm.

[0080] Figure 5 A method 500 for detecting the distance from a probe to the dental pulp of a tooth, according to a proposed embodiment, is shown. The method includes steps 510, 520, and 530. In step 510, tooth tissue of the tooth is irradiated by a probe placed in contact with the tooth surface, and data representing scattered light from the tooth tissue is received. In step 520, the spectrum of the scattered light is acquired (522), and then analyzed (524, 526) to obtain a spectral analysis result (528). In step 530, the distance from the probe to the dental pulp of the tooth is determined based on the spectral analysis result (528).

[0081] Spectral analysis 520 includes the methods described in steps 522, 524, 526, and 528. In step 522, a spectrum in the wavelength range of 300-800 nm is acquired. It should be noted that scattered light includes light having a wavelength range of 300-800 nm. In step 524, the intensity of the spectrum in the 300-800 nm range is determined. In step 526, a light absorption peak is detected, wherein the wavelength range of the light absorption peak characterizes the wavelength range of the light absorption spectrum of blood. The wavelength range of the light absorption spectrum of blood is within 520-540 nm and 550-570 nm. In step 528, a spectral analysis result is obtained by determining the intensity 524 of the spectrum and by detecting the light absorption peak 526, wherein the wavelength range of the light absorption peak characterizes the wavelength range of the light absorption spectrum of blood. In step 530, an indication of the distance from the probe to the dental pulp of the tooth is determined using the intensity determined in step 524 and the light absorption peak detected in step 526.

[0082] Figure 6 A proposed method 600, according to a proposed embodiment, is shown for detecting the distance from a probe (in contact with the tooth) to the dental pulp during dental drilling. The proposed method utilizes spectroscopy, wherein a light source is used to irradiate tissue via an optical fiber. The light is scattered and absorbed in the tissue, and the reflected light is then collected by another or the same optical fiber and directed to a spectrometer.

[0083] Method 600 includes steps 610, 620, 630, 640, and 650. In step 610, a dental drill is initiated into the tooth tissue. In step 620, the tooth tissue is illuminated with light through a probe, and data representing the scattered light from the tooth tissue is received. It should be noted that the scattered light includes light with a wavelength range of 300-800 nm. In step 630, the spectrum of the scattered light from the tooth tissue is acquired and then analyzed to obtain spectral analysis results. In step 640, the distance from the probe to the dental pulp is determined based on the spectral analysis results. In step 650, drilling is stopped if the desired distance to the dental pulp is reached.

[0084] The spectroscopic analysis method 630 further includes steps 631, 632, 633, 634, 635, and 636. First, step 630 includes acquiring a spectrum in the wavelength range of 300-800 nm, and then determining the intensity of the spectrum in the 300-800 nm range. The spectrum includes a measured reflectance spectrum generated by a spectrometer.

[0085] In step 631, light absorption peaks are detected, wherein the wavelength range of the light absorption peaks characterizes the wavelength range of the light absorption spectrum of the blood. The light absorption peak detection method includes analyzing a previously generated measured reflectance spectrum and observing troughs of amplitude variation within the wavelength range. These troughs serve as indicators of light absorption by the blood and thus correspond to light absorption peaks. If a light absorption peak is detected, light absorption peak algorithm 632 is applied. If no light absorption peak is detected, integral amplitude evaluation algorithm 633 is applied.

[0086] In step 632, the Light Absorption Peak (LAP) algorithm is applied. First, light absorption peaks in the 300-800 nm range are detected. The wavelength range of the blood light absorption spectrum is applied; therefore, light absorption peaks should be observed in the 520-550 nm and 570-590 nm ranges. The light absorption peaks correspond to the first and second troughs in the amplitude variation of the spectrum in the 520-550 nm and 570-590 nm ranges, respectively. Preferably, the first and second troughs in the amplitude variation of the spectrum are observed at 550 nm and 580 nm, respectively. The LAP algorithm utilizes the fact that blood absorption of light has two well-defined peaks near 540 nm and 580 nm because more blood will absorb light when the probe is close to the dental pulp, thus the amplitude of the spectrum will show a sharp decrease near these wavelengths. The relative decrease in amplitude is a measurement of the distance to the dental pulp. By fitting the spectrum, the relative decrease can be estimated, thereby estimating the distance to the dental pulp. The light absorption peak detection algorithm 632 enables the determination of the distance 640 from the probe to the dental pulp of the tooth.

[0087] In step 633, an integration operation is performed on the intensity of the determined scattered light spectrum in the range of 300-800 nm. If the probe is close to the dental pulp, absorption will occur, and therefore the integrated value of the intensity will decrease.

[0088] In step 634, the integral amplitude value is analyzed. If the integral amplitude value is not equal to zero, it can be compared with a threshold to determine the distance 640 from the dental probe to the dental pulp. If the integral amplitude value is equal to zero, the light intensity of the probe must be increased, but this depends on whether the maximum light intensity 635 has been reached.

[0089] In step 635, it is determined whether the maximum light intensity of the probe has been reached. If the maximum light intensity has not been reached, the light intensity is insufficient to produce an integral amplitude greater than zero. Therefore, the light intensity of the probe must be increased 636. If the maximum light intensity of the probe has been reached, the integral amplitude value is zero because the light is absorbed by the blood. Therefore, the drill bit is at the nearest safe drilling distance and drilling should not continue; therefore, drilling must be stopped 650 to avoid pulp exposure.

[0090] In step 636, the light intensity of the probe is increased, and the light absorption peak detection in step 631 is repeated.

[0091] In step 640, the determined intensity and detected light absorption peak are used to determine the distance from the probe to the dental pulp. The following criteria are given for determining this distance: If the integrated amplitude value is above a certain threshold and no blood peak is detected, no light reaches the blood, as all light is reflected by the dentin; therefore, the distance to the pulp is in the range of 2-1 mm. If the integrated amplitude is below a certain threshold and a blood peak is detected, light is only partially reflected by the dentin and reaches the blood; therefore, the distance to the pulp is in the range of 1-0.2 mm. If the integrated amplitude is below a certain threshold and no blood peak is detected, all light is absorbed by the blood, and no light returns to the probe; therefore, the distance to the pulp is less than 0.2 mm. This is the closest safe drilling distance to avoid pulp exposure. A more precise distance to the pulp can be determined by looking up the value of the integrated amplitude or blood peak detection parameter in a lookup table that correlates the measured parameters with the known dentin slice thickness.

[0092] In step 641, the desired distance to the dental pulp is compared with the probe-to-pulp distance previously determined in step 640. If the determined distance has reached the desired distance to the dental pulp, drilling stops at 650. If the determined distance has not yet reached the desired distance to the dental pulp, drilling continues at 610 and method 600 is repeated.

[0093] As another example Figure 7 An example of a computer 700 in which one or more portions of an embodiment may be employed is shown. The various operations discussed above can utilize the capabilities of computer 700. For example, the ability to instruct a subject's respiratory muscles can be incorporated into any element, module, application, and / or component discussed herein. In this regard, it should be understood that system functional blocks can operate on a single computer or can be distributed across multiple computers and locations (e.g., via an internet connection).

[0094] Computer 700 includes, but is not limited to, PCs, workstations, laptops, PDAs, handheld devices, servers, storage devices, etc. Typically, in terms of hardware architecture, computer 700 may include one or more processors 710, memory 720, and one or more I / O devices 770 communicatively coupled via a local interface (not shown). The local interface may be, for example, but not limited to, one or more buses or other wired or wireless connections, as known in the art. The local interface may have additional elements for implementing communication, such as controllers, buffers (caches), drivers, repeaters, and receivers. Furthermore, the local interface may include address, control, and / or data connections to enable appropriate communication between the aforementioned components.

[0095] Processor 710 is a hardware device for executing software that can be stored in memory 720. Processor 710 can actually be any custom or commercially available processor, central processing unit (CPU), digital signal processor (DSP), or auxiliary processor among several processors associated with computer 700, and processor 710 can be a semiconductor-based microprocessor (in the form of a microchip) or microprocessor.

[0096] Memory 720 may include volatile memory elements (e.g., random access memory (RAM), such as dynamic random access memory (DRAM), static random access memory (SRAM), etc.) and non-volatile memory elements (e.g., ROM, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic tape, optical disc read-only memory (CD-ROM), magnetic disk, floppy disk, magnetic tape cassette, cassette tape, etc.). Furthermore, memory 720 may include electronic, magnetic, optical, and / or other types of storage media. Note that memory 720 may have a distributed architecture, where various components are geographically separated but accessible by processor 710.

[0097] The software in memory 720 may include one or more individual programs, each including an ordered list of executable instructions for implementing logical functions. According to an exemplary embodiment, the software in memory 720 includes a suitable operating system (O / S) 750, a compiler 740, source code 730, and one or more applications 760. As shown, application 760 includes multiple functional components for implementing the features and operations of the exemplary embodiment. Application 760 of computer 700 may represent various applications, computing units, logic, functional units, processes, operations, virtual entities, and / or modules according to the exemplary embodiment, but application 760 is not intended to be limiting.

[0098] Operating system 750 controls the execution of other computer programs and provides scheduling, input / output control, file and data management, memory management, communication control, and related services. The inventors envision that application 760, used to implement the exemplary embodiments, can be applied to all commercially available operating systems.

[0099] Application 760 can be a source program, an executable program (object code), a script, or any other entity including a set of instructions to be executed. When it is a source program, the program is typically translated by a compiler (such as compiler 740), assembler, interpreter, etc., which may or may not be included in memory 720, in order to operate correctly in conjunction with O / S 750. Furthermore, application 760 can be written in an object-oriented programming language with data and method classes, or a procedural programming language with routines, subroutines, and / or functions, such as, but not limited to, C, C++, C#, Pascal, BASIC, API calls, HTML, XHTML, XML, ASP scripts, JavaScript, FORTRAN, COBOL, Perl, Java, ADA, .NET, etc.

[0100] I / O device 770 may include input devices, such as, but not limited to, a mouse, keyboard, scanner, microphone, camera, etc. Furthermore, I / O device 770 may also include output devices, such as, but not limited to, a printer, monitor, etc. Finally, I / O device 770 may also include devices for transmitting both input and output, such as, but not limited to, a NIC or modulator / demodulator (for accessing remote devices, other files, devices, systems, or networks), radio frequency (RF) or other transceivers, telephone interfaces, bridges, routers, etc. I / O device 770 also includes components for communication over various networks, such as the Internet or intranets.

[0101] If the computer 700 is a PC, workstation, intelligent device, etc., the software in the memory 720 may also include a Basic Input / Output System (BIOS) (omitted for simplicity). The BIOS is a set of basic software routines used to initialize and test the hardware at startup, boot the O / S 750, and support data transfer between hardware devices. The BIOS is stored in some type of read-only memory, such as ROM, PROM, EPROM, EEPROM, etc., so that the BIOS can be executed when the computer 700 is activated.

[0102] When the computer 700 is operating, the processor 710 is configured to execute software stored in the memory 720, transfer data to and from the memory 720, and typically control the operation of the computer 700 according to the software. Applications 760 and O / S 750 are read, in whole or in part, by the processor 710, may be buffered within the processor 710, and then executed.

[0103] When application 760 is implemented in software, it should be noted that application 360 can be stored on virtually any computer-readable medium for use by or in connection with any computer-related system or method. In the context of this document, a computer-readable medium can be an electronic, magnetic, optical, or other physical device or component that can contain or store computer programs for use by or in connection with a computer-related system or method.

[0104] Application 760 can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, a processor-containing system, or other system that can fetch and execute instructions from and from the instruction execution system, apparatus, or device. In the context of this document, "computer-readable medium" can be any means capable of storing, transmitting, propagating, or transporting a program for use by or in connection with an instruction execution system, apparatus, or device. Computer-readable media can be, for example, but not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, devices, or propagation media.

[0105] This invention can be a system, method, and / or computer program product. A computer program product may include one or more computer-readable storage media having computer-readable program instructions thereon for causing a processor to perform aspects of the invention.

[0106] Computer-readable storage media can be tangible devices that can retain and store instructions for use by an instruction execution device. Computer-readable storage media can be, for example, but not limited to, electronic storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing.

[0107] This document describes aspects of the invention with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer-readable program instructions.

[0108] A single processor or other unit can perform the functions of several items described in the claims.

[0109] It should be understood that the disclosed methods are computer-implemented methods. Therefore, the concept of a computer program is also proposed, which includes code means for implementing any of the above methods when the program is run on a processing system.

[0110] Those skilled in the art will readily be able to develop processors for performing any of the methods described herein. Therefore, each step of the flowchart can represent a different action performed by the processor and can be executed by the corresponding module of the processor.

[0111] As described above, this system utilizes a processor to perform data processing. The processor can be implemented in various ways, using software and / or hardware, to perform a variety of required functions. The processor typically employs one or more microprocessors, which can be programmed using software (e.g., microcode) to perform the required functions. The processor can be implemented as a combination of dedicated hardware for performing certain functions and one or more programmable microprocessors and associated circuitry for performing other functions.

[0112] Examples of circuit systems that may be used in the various embodiments of this disclosure include, but are not limited to, conventional microprocessors, application-specific integrated circuits (ASICs), and field-programmable gate arrays (FPGAs).

[0113] In various implementations, a processor may be associated with one or more storage media, such as volatile and non-volatile computer memories, such as RAM, PROM, EPROM, and EEPROM. The storage media may be encoded with one or more programs that perform the required functions when executed on one or more processors and / or controllers. Various storage media may be fixed within the processor or controller, or they may be transportable, allowing one or more programs stored thereon to be loaded into the processor.

[0114] Figure 8 A dental device 800 for determining the distance from a probe 802 to the dental pulp 814 of a tooth 810, according to a proposed embodiment, is shown. The device includes a probe 802 and a processor 804. The probe 802 is configured to illuminate the tooth tissue of the tooth 810 with light and detect scattered light from the tooth tissue. The tooth 810 includes dentin 812 and dental pulp 814. The tooth tissue is illuminated with light comprising at least two different colors and having a wavelength range of 300-800 nm.

[0115] Processor 804 is configured to acquire the spectrum of the detected scattered light; obtain spectral analysis results from the spectrum; and determine the distance from probe 802 to the dental pulp 814 of tooth 810 based on the spectral analysis results. It should be noted that the spectrum is equal to the intensity of at least two optical wavelengths. Processor 804 is configured to acquire the spectrum of the detected scattered light in the wavelength range of 300-800 nm. To obtain spectral analysis results from the spectrum, the intensity of the spectrum in the 300-800 nm range is determined, wherein determining the intensity also includes determining the intensity as a part of the spectrum. Furthermore, to obtain spectral analysis results from the spectrum, light absorption peaks are detected, wherein the wavelength range of the light absorption peaks characterizes the wavelength range of the blood absorption spectrum. The wavelength range of the blood absorption spectrum is within 520-540 nm and 550-570 nm.

[0116] Figure 9 A proposed dental device 900 for determining the distance from probe 910 to the dental pulp 944 of tooth 940 is shown. The device includes a dental probe 910 and a processor 920. The dental probe 910 includes an optical fiber 930 and is positioned in use adjacent to the tooth tissue of tooth 940, which is fixed to the gingiva 950. The tooth tissue includes dentin 942 and dental pulp 944.

[0117] A dental probe 910 is configured to illuminate the tooth tissue of a tooth 940 with light and detect scattered light from the tooth tissue, wherein the light must include at least two different colors. Therefore, the dental probe 910 includes a light source 912 for emitting light and a spectrometer 914 for detecting the scattered light from the tooth tissue. The light includes light with a wavelength range of 300-800 nm. In the proposed embodiment, the light source 912 includes a light-emitting diode (LED), and the spectrometer 914 includes a photodetector. Furthermore, the dental probe 910 includes an optical fiber 930 that guides the light 932 emitted from the light source 912 to the tooth tissue of the tooth 940. The optical fiber 930 also guides the scattered light 934 reflected from the tooth tissue of the tooth 940 to the spectrometer 914.

[0118] Processor 920 is configured to acquire the spectrum of the detected scattered light; obtain spectral analysis results from the spectrum; and determine the distance from probe 910 to the dental pulp 944 of tooth 940 based on the spectral analysis results. It should be noted that the spectrum equals the intensity of at least two optical wavelengths, and the processor is configured to acquire the spectrum of the detected scattered light in the wavelength range of 300-800 nm. To obtain the spectral analysis results from the spectrum, the intensity of the spectrum in the 300-800 nm range is determined, wherein determining the intensity also includes determining the intensity as a part of the spectrum. Furthermore, to obtain the spectral analysis results from the spectrum, light absorption peaks are detected, wherein the wavelength range of the light absorption peaks characterizes the wavelength range of the blood absorption spectrum. The wavelength range of the blood absorption spectrum is within 520-550 nm and 570-590 nm. An integration operation is then performed on the determined intensity of the scattered light spectrum.

[0119] Processor 920 is configured to determine the distance from probe 910 to the pulp 944 of tooth 940 based on spectral analysis results, including information on the integrated amplitude of the spectrum and the detection of light absorption peaks. If the integrated amplitude of the spectrum exceeds a threshold and no light absorption peak is detected, the processor is configured to determine that the distance from probe 910 to the pulp 944 of tooth 940 is in the range of 1-2 mm. If the integrated amplitude of the spectrum is below the threshold and a light absorption peak is detected, the processor is configured to determine that the distance from probe 910 to the pulp 944 of tooth 940 is in the range of 0.2-1 mm. If the integrated amplitude of the spectrum is below the threshold and no light absorption peak is detected, the processor is configured to determine that the distance from probe 910 to the pulp 944 of tooth 940 is less than 0.2 mm. Processor 920 is configured to measure the distance through dentin 942 to pulp 944 in real time. Therefore, when a certain distance to pulp 944 is reached, it issues an alert mechanism to the dentist.

[0120] Figure 10 An embodiment 1000 of a probe is shown, comprising two optical fibers 1010 and 1020 that guide light to tooth tissue 1030, which includes dentin 1032 and pulp 1034. The probe embodiment 1000 also includes a light source 1002 and a spectrometer 1004. Optical fiber 1010 guides light 1012 emitted from the light source 1002 to the tooth tissue 1030. Optical fiber 1020 guides reflected, scattered light 1022 from the tooth tissue 1030 to the spectrometer 1004.

[0121] Figure 11An embodiment of a probe 1100 is shown, comprising an optical fiber 1110 and a beam splitter 1116, wherein the optical fiber guides light to / from tooth tissue 1120, which includes dentin 1122 and pulp 1124. The probe embodiment 1100 also includes a light source 1102 and a spectrometer 1104. The optical fiber 1110 guides light 1112 emitted from the light source 1102 to the tooth tissue 1120. When used in conjunction with the beam splitter 1116, the optical fiber 1110 also guides scattered light 1114 reflected from the tooth tissue 1120 to the spectrometer 1104.

[0122] Figure 12 A drill bit embodiment 1200 including a dental device 1210 is shown. The drill bit embodiment includes a drill head 1202 fixed to a drill mouth portion 1204. In use, the curved distal end of the drill head 1202 is positioned adjacent to the tooth tissue of a tooth 1220, which includes dentin 1222 and pulp 1224. The dental device 1210 includes a dental probe 1212 and a processor 1214. The drill head 1202 is large enough to accommodate an optical fiber, so the distal end of the dental probe 1212 is located within the drill head 1202. Therefore, the dental probe 1212 is also very close to the tooth tissue of the tooth 1220 and is configured to illuminate the tooth tissue with light and detect scattered light from the tooth tissue. The light includes light with a wavelength range of 300-800 nm and includes at least two different colors.

[0123] Processor 1214 is configured to acquire the spectrum of detected scattered light; obtain spectral analysis results from the spectrum; and determine the distance from probe 1212 to the dental pulp 1224 of tooth 1220 based on the spectral analysis results. It should be noted that the spectrum is equal to the intensity of at least two optical wavelengths. Processor 1214 is configured to acquire the spectrum of detected scattered light in the wavelength range of 300-800 nm. To obtain spectral analysis results from the spectrum, the intensity of the spectrum in the 300-800 nm range is determined, wherein determining the intensity also includes determining the intensity as a part of the spectrum. Furthermore, to obtain spectral analysis results from the spectrum, light absorption peaks are detected, wherein the wavelength range of the light absorption peaks characterizes the wavelength range of the blood absorption spectrum. The wavelength range of the blood absorption spectrum is within 520-550 nm and 570-590 nm.

[0124] By studying the accompanying drawings, this disclosure, and the appended claims, those skilled in the art can understand and implement variations of the disclosed embodiments in practicing the claimed invention. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plural.

[0125] The fact that certain measures are enumerated only in mutually distinct dependent claims does not imply that a combination of these measures cannot be used for an advantageous purpose. If the term "suitable" is used in the claims or description, it should be noted that the term "suitable" is intended to be equivalent to the term "configured as". Any reference numerals in the claims should not be construed as limiting the scope.

Claims

1. A method for detecting the distance from a probe to the dental pulp of a tooth by determining an indication of the thickness of the dentin, comprising: Receive (510) data representing scattered light from tooth tissue irradiated by the probe, wherein the scattered light comprises light having a wavelength in the range of 300-800 nm; Obtain the spectrum of the scattered light in the wavelength range of 300-800 nm as described in (522); Obtaining (528) spectral analysis results from the spectrum, wherein obtaining the spectral analysis results from the spectrum includes: detecting (526) light absorption peaks, wherein the wavelength range of the light absorption peaks characterizes the wavelength range of the light absorption spectrum of blood; and Based on the spectral analysis results, an indication of the thickness of the dentin in the tooth is determined (530). in: If the integral amplitude of the spectrum in the range of 400 nm to 600 nm exceeds a predetermined threshold, and no light absorption peak is detected in the range of 400 nm to 600 nm, then the thickness of the dentin is determined to be in the range of 2 mm to 1 mm. If the integrated amplitude of the spectrum in the range of 400 nm to 600 nm does not exceed the predetermined threshold, and a light absorption peak is detected in the range of 400 nm to 600 nm, then the thickness of the dentin is determined to be in the range of 1 mm to 0.2 mm; and If the integral amplitude of the spectrum in the range of 400 nm to 600 nm does not exceed the predetermined threshold, and no light absorption peak is detected in the range of 400 nm to 600 nm, then the thickness of the dentin is determined to be less than 0.2 mm.

2. The method according to claim 1, wherein the wavelength range of the light absorption spectrum of the blood is within 520-550 nm and 570-590 nm.

3. A dental device for determining the distance from a probe to the dental pulp of a tooth by measuring an indicator of the thickness of the dentin, comprising: The probe (802) is configured to irradiate the tooth tissue with light and detect scattered light from the tooth tissue, wherein the light includes light having a wavelength range of 300-800 nm. The processor (804) is configured as follows: Obtain the spectrum of the detected scattered light in the wavelength range of 300-800 nm; Obtaining spectral analysis results from the spectrum, wherein obtaining spectral analysis results from the spectrum includes: detecting light absorption peaks, wherein the wavelength range of the light absorption peaks characterizes the wavelength range of the blood's absorption spectrum; and Based on the spectral analysis results, an indicator of the thickness of the dentin in the tooth is determined. The processor (804) is configured to: If the integrated amplitude of the spectrum in the range of 400 nm to 600 nm exceeds a predetermined threshold, and no light absorption peak is detected in the range of 400 nm to 600 nm, then the thickness of the dentin is determined to be in the range of 2 mm to 1 mm. If the integral amplitude of the spectrum in the range of 400 nm to 600 nm does not exceed the predetermined threshold, and a light absorption peak is detected in the range of 400 nm to 600 nm, then the thickness of the dentin is determined to be in the range of 1 mm to 0.2 mm. If the integral amplitude of the spectrum in the range of 400 nm to 600 nm does not exceed the predetermined threshold, and no light absorption peak is detected in the range of 400 nm to 600 nm, then the thickness of the dentin is determined to be less than 0.2 mm.

4. The apparatus according to claim 3, wherein the wavelength range of the absorption spectrum of the blood is within 520-550 nm and 570-590 nm.

5. A drill bit comprising a dental device according to any one of claims 3 to 4.

6. A computer program product comprising a computer program code means, which, when executed on a computing device having a processing system, causes the processing system to perform all the steps of the method according to any one of claims 1 to 2 when performed by a dental device according to any one of claims 3 to 4.

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