WO2014053932A1

WO2014053932A1 - A system for developing tooth whitening protocols

Info

Publication number: WO2014053932A1
Application number: PCT/IB2013/058514
Authority: WO
Inventors: Nigel David Young; Steve John BATTERSBY; Paul David BATTERSBY
Original assignee: Koninklijke Philips N.V.
Priority date: 2012-10-01
Filing date: 2013-09-13
Publication date: 2014-04-10

Abstract

A system for developing a tooth whitening protocol is provided. The system includes a measuring device for measuring tooth enamel thickness and a measuring device for measuring tooth color. A computing resource includes a processor and a memory storing at least one application executable by the processor. The memory includes one or more data look-up tables including a compilation of scattering and transmission properties associated with specific tooth enamel thicknesses. The processor utilizes the at least one application to approximate tooth dentin based on a measured tooth enamel thickness and measured tooth color to develop a specific tooth whitening protocol.

Description

A SYSTEM FOR DEVELOPING TOOTH WHITENING PROTOCOLS

PRIORITY

[0001] This application claims priority to a U.S. Provisional Application filed on October

1, 2012 titled "Enamel Thickness Determination Systems" and assigned U.S. Provisional

Application Serial No. 61/708,077; the entire contents of which are incorporated herein by reference.

BACKGROUND

Technical Field

[0002] The present disclosure relates to a system for developing tooth whitening protocols. More particularly, the present disclosure relates to a system that utilizes tooth color and tooth enamel thickness to determine tooth dentin color for developing tooth whitening protocols.

Description of Related Art

[0003] There is a general desire for people to have white teeth. Such white teeth are an indication of a good health and in particular good oral care health. Various foods, beverages (e.g., coffee, tea and cola beverages) and the use of tobacco, however, will sometimes stain or discolor teeth.

[0004] The tooth structures that are generally responsible for presenting a stained appearance are enamel, dentin, and the acquired pellicle. Tooth enamel is predominantly formed from inorganic material, mostly in the form of hydroxyapatite crystals, and further contains approximately 5% organic material primarily in the form of collagen. In contrast, dentin is composed of about 20% protein including collagen, the balance consisting of inorganic material, predominantly hydroxyapatite crystals, similar to that found in enamel. The acquired pellicle is a proteinaceous layer on the surface of tooth enamel which reforms rapidly after an intensive tooth cleaning.

[0005] Various products and procedures have been developed to whiten teeth. These products and procedures are either purchased and/or used directly by the consumer or are applied by a dental or other professional. The more effective products and procedures are those that are performed by a dental professional.

[0006] Typically this consists of the dental professional forming a dental tray from an impression of a person's teeth. Custom dental trays can be created by any of the procedures, well known in the art. After the dental tray is formed to the structure of the teeth a whitening formulation, e.g., a bleaching agent, is placed in the tray and the tray placed into the mouth and against the teeth to be treated. A dental tray having whitening composition for in-home use is typically left in the mouth for from about 10 minutes to several hours, i.e., up to 12 or more hours. If the treatment occurs in the dental office, the time of the treatment typically will be from about 0.5 hour to about 2 hours.

[0007] The products used solely by consumers primarily include whitening strips and brush-on products. Whitening strips are plastic strips with the whitening formulation, e.g., a bleaching agent, on one surface. The surface with the whitening formulation is pressed against one's teeth and left in contact with the teeth for about 30 minutes. The plastic strip then is removed. The brush-on products are painted into teeth and the user keeps his/her mouth at least partially open for up to about a minute until the formulation dries onto the teeth.

[0008] While the aforementioned methods of tooth whitening are satisfactory for their intended purposes, neither of these methods is tailored to a specific individuals tooth characteristics. For example, through empirical testing it has been found that teeth with dark dentin are harder to bleach than teeth with lighter colored dentin. As can be appreciated, exposing teeth with lighter colored dentin to the same tooth whitening protocol as would be required for teeth with a heavily darkened dentin is likely to lead to over consumption of materials and/or unnecessary pain and tooth sensitivity.

SUMMARY

[0009] As can be appreciated, a system that utilizes tooth color and tooth enamel thickness to determine tooth dentin color for developing tooth whitening protocols may prove useful in cosmetic dentistry.

[0010] An aspect of the present disclosure provides a system for developing or formulating a tooth whitening protocol. The system includes a measuring device for measuring tooth enamel thickness and a measuring device for measuring tooth color. A computing resource includes a processor and a memory storing at least one application executable by the processor. The memory includes one or more data look-up tables including a compilation of scattering and transmission properties associated with specific tooth enamel thicknesses. The processor utilizes the at least one application to approximate tooth dentin based on a measured tooth enamel thickness including specific scattering and transmission properties associated therewith and measured tooth color to develop a specific tooth whitening protocol.

[0011] The device for measuring tooth enamel thickness may be an ultrasound device.

The device for measuring tooth color may be a subjective color matching scheme and/or an objective color matching scheme. In the former instance, the subjective color matching scheme may be a shade guide, e.g., a toothguide, linearguide and bleachguide. Alternatively, in the latter instance, the objective color matching scheme may be a color-matching instrument and a digital imaging system that includes a CCD camera, a lighting setup and/or a computer. [0012] An aspect of the present disclosure provides a method for developing a tooth whitening protocol. Tooth enamel thickness and tooth color is measured. Thereafter, the measured tooth enamel thickness is compared with known tooth enamel thicknesses to obtain scattering and transmission properties associated with the measured tooth enamel thickness. Subsequently, tooth dentin based on the measured tooth enamel thickness and tooth color is approximated. And, a tooth whitening protocol based on the approximated tooth dentin is developed.

[0013] A computing resource may be provided. The computing resource may include a processor and a memory storing one or more application executable by the processor. The memory may include one or more data look-up tables including a compilation of the known scattering and transmission properties associated with specific tooth enamel thicknesses. The processor may utilize the application(s) to approximate tooth dentin based on a measured tooth enamel thickness including specific scattering and transmission properties associated therewith and measured tooth color to develop a specific tooth whitening protocol.

[0014] An ultrasound device may be utilized to measure tooth enamel thickness. And, a subjective color matching scheme and/or an objective color matching scheme may be utilized to measure tooth color.

[0015] An aspect of the present disclosure provides a nontransitory computer readable medium storing a program for developing a tooth whitening protocol. The program including instructions that are executable by a computing resource. The computer readable medium configured to execute the aforementioned method. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The aspects of the present disclosure may be better understood with reference to the following figures. The components in the figures are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the disclosure. Moreover, in the figures, like reference numerals designate corresponding parts throughout the several views.

[0017] In the figures:

[0018] Fig. 1 is a simplified block diagram illustrating a system for developing a tooth whitening protocol according to the present disclosure;

[0019] Fig. 2 is a graphical representation of luminosity of a tooth vs. luminosity of the underlying dentin; and

[0020] Fig. 3 is a flowchart illustrating a method utilizing the system depicted in Fig. 1.

DETAILED DESCRIPTION

[0021] The present disclosure describes various embodiments of systems, devices, and methods that utilize tooth color and one or more properties related to tooth enamel thickness to determine tooth dentin color for developing or formulating tooth whitening protocols. In accordance with the instant disclosure, measurements of tooth color are combined with co- located measurements of tooth enamel thickness for predicting the color of the underlying dentin. The underlying color of the dentin may be utilized for monitoring tooth discoloration and provides a method for customizing a tooth whitening protocol to achieve an optimum end result with minimum exposure to known whitening formulations, e.g., bleaching agents.

[0022] As is known in the art, human teeth are made of two main constituents, the dentin and an overlying hard enamel layer. Although there are several sources of external (or extrinsic) tooth discoloration, the main source of internal (or intrinsic) tooth discoloration is a slow darkening of the dentin color which is visible through the enamel layer.

[0023] In accordance with the instant disclosure, a non-invasive system and method of estimating a color of the underlying dentin based on combining measurements of tooth color with co-located measurements of enamel thickness is provided. These two measurements, when combined with scattering and transmission properties of human enamel, allow the underlying dentin color to be predicted which can then be utilized to develop a tooth whitening protocol for a specific individual.

[0024] Fig. 1 illustrates a system 2 that is configured to develop a tooth whitening protocol. The three (3) main components of system 2 include a device 4 that is configured for measuring tooth color, a device 6 that is configured for measuring tooth enamel thickness and a computing resource 8 that is configured to utilize calculated tooth color and calculated tooth enamel thickness to approximate an underlying tooth dentin color and, subsequently, develop a tooth whitening protocol 10 for an end user, e.g., a dentist, a consumer, etc.

[0025] Continuing with reference to Fig. 1 , device 4 may be any suitable device (method or process) that is capable of measuring tooth color. In an embodiment, for example, a subjective color matching scheme 12 may be utilized to determine tooth color. In this particular embodiment, one or more types of shade guides 14 may be utilized to determine tooth color. Shade guides 14 are commonly utilized to determine tooth color and the specific type utilized may vary. For example, shade guides 14 that may be utilized with system 2 may include but are not limited to toothguides 16, linearguides 18 and bleachguides 20. Operation of these various types of shade guides 14 is known and, therefore, is not described herein. [0026] In an embodiment, an objective color matching scheme 22 may be utilized to determine tooth color. In this particular embodiment, for example, one or more color-matching instruments 24 may be utilized to determine tooth color. Color matching instruments 24 are, typically, handheld, electronic instruments that are utilized by a dentist professional to determine tooth color. A commercially available color matching instrument 24 that is suitable for use with system 2 is manufactured by VITA Company and sold under the trademark VITA Easyshade^® Compact. Alternatively, color matching scheme 22 may utilize a digital imaging system 26 to determined tooth color. In this particular embodiment, for example, digital imaging system 26 may include one or more CCD cameras 28, a lighting setup 30 and/or a computer 32. Operation of color matching instrument 24 and digital imaging system 26, and operable components associated therewith, is known and, therefore, is not described herein.

[0027] While subjective color matching scheme 12 and objective color matching scheme

22 have been described herein as being utilized separately from one another for determining tooth color, it is within the purview of the present disclosure that these schemes may be utilized collectively to determine tooth color. Moreover, these schemes are not to be construed as limiting, but merely examples of suitable tooth color matching schemes.

[0028] Device 6 may be any suitable device (method or process) that is capable for measuring tooth enamel thickness. In one particular embodiment, such as the illustrated embodiment, device 6 is an ultrasound device 34 (Fig. 1) that is configured to measure tooth enamel thickness in vivo. Other devices that may be utilized to measure tooth enamel thickness include, but are not limited to air pressure devices and electron microscopy devices. (Please provide additional information if known, or other suitable devices, methods or processes for measuring tooth enamel thickness.) [0029] Computing resource 8 is configured to receive data pertaining to tooth enamel color and tooth enamel thickness and based on this data approximate a corresponding tooth dentin color for determining a tooth whitening protocol. Computing resource 8 may be a server, computer, or another device providing computing capability. In some embodiments, for example, the computing resource 8 includes a plurality of computing resources that are arranged, for example, in one or more server banks, computer banks or other arrangements. Further, in some embodiments, computing resource 8 includes a cloud computing resource, a grid computing resource, or any other distributed computing arrangement. For illustrative purposes, computing resource 8 is referred to herein in the singular, but it is understood that a plurality of computing resources 8 may be employed in the various arrangements described above instead.

[0030] Computing resource 8 includes one or more processors 38 and a memory 40.

Memory 40 is a computer readable medium and may include both volatile and/or nonvolatile memory and data storage components. Memory 40 may comprise, for example, random access memory (RAM), read-only memory (ROM), hard disk drives, solid-state drives, USB flash drives, memory cards accessed via a memory card reader, floppy disks accessed via an associated floppy disk drive, optical discs accessed via an optical disc drive, magnetic tapes accessed via an appropriate tape drive, and/or other memory components, or a combination of any two or more of these memory components. In addition, the RAM may comprise, for example, static random access memory (SRAM), dynamic random access memory (DRAM), or magnetic random access memory (MRAM) and other such devices. The ROM may comprise, for example, a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), another like memory device. [0031] Memory 40 stores one or more applications 42 (or control algorithms) that are executable by processor 38 for developing tooth whitening protocol 10 for an end user. As defined herein, an end user can be a dental professional (e.g., dentist, hygienist, etc.) or individual consumer. Memory 40 includes one or more databases 46 that store user profiles 50 that may include, for example: previous whitening regimes; tooth characteristics (e.g., tooth color, tooth enamel thickness, dentin color, tooth sensitivity, tooth chips, cracks or the like, etc.); and personal data of a user (e.g., eating or drinking habits, toothpaste preference, etc.).

[0032] Memory 40 includes one or more data look-up tables 44 that include a compilation of scattering and transmission properties 48 that are associated with specific tooth enamel thicknesses. Scattering and transmission properties 48 may be acquired through measurement of a range of different samples of human enamel and utilized by application 42. Processor 38 executes the application 42 to approximate tooth dentin based on measured tooth enamel thickness (and scattering and transmission properties 48 associated therewith) and measured tooth color to develop a specific tooth whitening protocol.

[0033] In accordance with the instant disclosure it has been found through empirical testing that there is a direct correlation between tooth dentin color and whole tooth color. Specifically, a tooth analogue including a bovine enamel overlying colored paper was constructed. The bovine enamel was sectioned and polished to 1mm thickness and nine (9) colors were prepared on photographic paper. Measurements were made on the paper (which represented a dentine analogue) and on paper/enamel (which represented a tooth analogue) using a chromameter for both hydrated and desiccated paper/enamel.

[0034] With reference to Fig. 2, a graphical representation of a measured luminosity (L^*) for the paper/enamel (Tooth) as a function of the luminosity of the paper (Dentin) is illustrated. The data was fitted by the following expressions, derived from a mathematical model for the passage of light through the enamel to the dentin and back again:

(2) Z^* _Tootn =1 16i?^1/3-16

(3) R'=S + (fR/l - SR)

[0035] where R and R' are the reflectivities of the paper and paper/enamel combination and S and T are fitting parameters which represent the amount of light scattered and transmitted on the first pass through the enamel, see table 1 below:

Table 1

[0036] The color of the paper/enamel tooth analogue can also be predicted from the paper dentin analogue using:

(4) a Tooth/β Dentin =

= (R/R'†¹³ T²/(l -SR)²

[0037] From the foregoing, a theoretical model which relates (L^*, a^*, b^*) values for a colored surface to equivalent values when a thin slice of enamel is superimposed can be utilized to illustrate the correlation between tooth dentin and whole tooth color. Specifically, assuming bovine enamel is representative of human tooth enamel, dentine L^*= 60 correlates to whole L^*= 68 which is darkened (see Fig. 2 for example). As can be appreciated, this suggests that it is easier to whiten teeth when dentin is still relatively light in color as compared to when the dentin is dark. Additionally, the foregoing provides a way of measuring scattering, transmission and loss in enamel. [0038] Operation of system 2 is described in terms of a method 100 for developing a tooth whitening protocol 10. A dental patient may, initially, receive a routine dental cleaning from the hygienists. In one particular embodiment, a short whitening procedure may be performed to bleach surface stains not removed in the hygienist room; it should be noted, that this bleaching is not designed to bleach underlying dentin at this stage.

[0039] Thereafter, a dentist (or hygienist) may measure a color of the patient's tooth utilizing device 4, e.g., color matching instrument 24, see Fig. 3 at step 102. Subsequently, a dentist (or hygienist) may measure a thickness of the patient's tooth enamel utilizing ultrasound device 34, see Fig. 3 at step 104. By measuring tooth color and enamel thickness over a range of teeth provides the best estimate of an underlying dentin color; and may give more individual estimates for the enamel scattering and transmission properties for an individual patient.

[0040] The measured data may then be input to computer resource 8, which will have application 42 already stored in memory 40. Processor 38 executes the instructions in application 42. Specifically, processor 38 accesses data look-up table 44 and compares scattering and transmission properties 48 provided therein with the measured tooth enamel thickness, see Fig. 3 at step 106. One or more control algorithms 50 is provided with application 42 and is configured to utilize one or more of equations (l)-(4) and curve fitting techniques provided in Fig. 2 to approximate the underlying dentin color based on the scattering and transmission properties 48, see Fig. 3 at step 108.

[0041] Once an estimate for the dentine color has been made, the dentist would be able to give an initial indication of the severity of the discoloration, an indication of the overall improvement likely from tooth whitening and prepare a custom tooth whitening protocol for the patient, see Fig. 3 at step 110. In accordance with the instant disclosure, this custom tooth whitening protocol would utilize the aforementioned mathematical understanding linking dentin color to whole tooth color. That is, teeth with dark dentin are harder to bleach than teeth with

*

lighter colored dentin. To give a specific example, an increase in tooth lightness L (or 5) might

* *

be achieved by lightening the dentin by AL of 10 when the dentin L is 70 (relatively light) but

* *

might require a AL of 20 when the dentin L is 50 (relatively dark).

[0042] As can be appreciated, however, given long enough exposure to a whitening agent, all teeth will be optimally whitened. As noted above, however, exposing lighter colored teeth to the same whitening protocol as would be required for more heavily darkened teeth is likely to lead to over consumption of materials and unnecessary pain and tooth sensitivity. The uniqueness of system 2, however, provides the least invasive treatment for those with lighter colored underlying dentin. Moreover, system 2 encourages those with darker underlying dentin to stick with a specific whitening protocol until the improvement is complete.

[0043] From the foregoing and with reference to the various figure drawings, those skilled in the art will appreciate that certain modifications can also be made to the present disclosure without departing from the scope of the same. For example, in accordance with the instant disclosure, a computer readable medium 54 (Fig. 1), which is non-transient includes instructions for developing a tooth whitening protocol is provided. The instructions are executable by computing resource 8 and configured to execute aforementioned method 100.

[0044] Further, it is also possible, distribute computer readable medium 54 to users, allow users who meet certain requirements to download decryption key information from a website via the Internet, and allow these users to run the encrypted program by using the key information, whereby the program is installed in the user's computer. [0045] While several embodiments of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.

Claims

WHAT IS CLAIMED IS:

1. A system for developing a tooth whitening protocol, comprising:

a device for measuring tooth enamel thickness;

a device for measuring tooth color; and

a computing resource including:

a processor; and

a memory storing at least one application executable by the processor, the memory including at least one data look-up table including a compilation of scattering and transmission properties associated with specific tooth enamel thicknesses,

wherein the processor utilizes the at least one application to approximate tooth dentin based on a measured tooth enamel thickness including specific scattering and transmission properties associated therewith and measured tooth color to develop a specific tooth whitening protocol.

2. The system according to claim 1 , wherein the device for measuring tooth enamel thickness is an ultrasound device.

3. The system according to claim 1, wherein the device for measuring tooth color is one of a subjective color matching scheme and an objective color matching scheme.

4. The system according to claim 3, wherein the subjective color matching scheme is a shade guide selected from the group consisting of a toothguide, linearguide and bleachguide.

5. The system according to claim 3, wherein the objective color matching scheme is one of a color-matching instrument and a digital imaging system that includes at least one of a CCD camera, a lighting setup and a computer.

6. A method for developing a tooth whitening protocol, comprising:

measuring tooth enamel thickness;

measuring tooth color;

comparing the measured tooth enamel thickness with known tooth enamel thicknesses to obtain scattering and transmission properties associated with the measured tooth enamel thicknesses;

approximating the tooth dentin based on the measured tooth enamel thickness and tooth color; and

developing a tooth whitening protocol based on the approximated tooth dentin.

7. The method according to claim 6, including providing a computing resource including:

a processor; and

a memory storing at least one application executable by the processor, the memory including at least one data look-up table including a compilation of the known scattering and transmission properties associated with specific tooth enamel thicknesses, wherein the processor utilizes the at least one application to approximate tooth dentin based on a measured tooth enamel thickness including specific scattering and transmission properties associated therewith and measured tooth color to develop a specific tooth whitening protocol.

8. The method according to claim 6, including utilizing an ultrasound device to measure tooth enamel thickness.

9. The method according to claim 6, including utilizing one of a subjective color matching scheme and an objective color matching scheme.

10. A nontransitory computer readable medium storing a program for developing a tooth whitening protocol, the program including instructions that are executable by a computing resource, the computer readable medium being configured to execute the method of claim 6.