The functionality of CaviTAU®

CaviTAU® Basis- und Handgerät

Ultrasound-based imaging has been a safe and minimally invasive technology in medicine since the 1940s. CaviTAU® does not use the standard ultrasound technique, which evaluates the range or background of reflected sound signals, but instead picks up sound waves that remain after the sound has completely traversed the bone. This technique is based onsound penetrating dry and solid bone tissue faster than water (or liquid fat in fat cells) or softened bone tissue. Therefore, fatty-degenerative osteonecrotic and osteolytic osteopathies (FDOJ/“NICO”), with many hollow, air-filled cavities and dry and fibrous medullary changes, can be detected with CaviTAU®. CaviTAU® is thus a safe and effective imaging test method for alveolar cancellous bone.

Quick detection and localization of cavitators

CaviTAU® relates to detecting and locating dental cavitations in jawbones using Through-Transmission Alveolar Ultrasonography (TAU). CaviTAU® generates an ultrasound pulse and passes the frequency through the jawbone. The pulse is detected and monitored subsequently by an ultrasound receiving unit. Attenuations of the amplitude of the pulse are indicative of pathological changes in the jawbone. The results are displayed on a color monitor, showing different colors according to varying degrees of attenuation (Figure 1 and 2).

Figure 1: Detailed colour schemes of anatomical structures with different densities in upper jawbone seen through the new CaviTAU®

Figure 2: Detailed colour schemes of anatomical structures with different densities in lower jawbone seen through the new CaviTAU®

Figure 3: Figure 3 shows the new CaviTAU® dashboard, which is not explained in detail here. Shown here is the integration of the patient’s actual OPG to ensure orientation during the enoral measuring. Every single area is enlarged and displayed on the upper right for a detailed interpretation of bone density. All 2D graphs can be presented in a 3D format and tilted and zoomed.

Typically, ultrasound is reflected from the cortical bone (outer bone layer of the jawbone), so CaviTAU® operates at a specific frequency of 2.5 – 2.75 MHz to penetrate the cortex. CaviTAU® measures the attenuation in the speed of sound after it passes through the fatty-degenerative areas of a cavity bladder with osteolysis/osteonecrosis.

A computer evaluates the speed and strength of the generated sound after it has traversed the bone. It transforms the signal into a three-dimensional color-coded picture. Thus, the image is color-coded to make the strength of the destruction understandable to the patient as well:

GREEN = Healthy and solid bone and tooth structures
YELLOW / ORANGE = Median stage of chronic fatty degeneration of pine osteitis
RED = Greasy dissolved jawbone with bacteria, toxins and extreme RANTES / CCL5 expression

In contrast to the precursor model “Cavitat,” the construction of CaviTAU® is designed around the transmitter’s fixed coplanarity located outside the mouth on the cheek with the receiver on the tongue or palate side within the mouth. This helps the CaviTAU® create objective measuring results.
Manipulation of the position of the transmitter and receiver by the user is excluded. The measurement itself is painless and only takes a short time. The intensive use of gel masses in the mouth is no longer necessary with CaviTAU®.

In men, it is important that no beard is present.

CaviTAU® device in use
CaviTAU® device in use
CaviTAU® cross view
CaviTAU® cross view

Brief description of CaviTAU®

Figure 4 shows the embodiment of the CaviTAU® handhold: The thick round element on the left, located below, is the ultrasonic transducer (2) and the thin round element is the ultrasonic receiver (3). Two arms connect to the handle on the right. An electrical cable in the rightmost position connects to the processing unit (not shown).

Figure 4: CaviTAU® measuring unit

One part of the measuring unit, preferably the transducer, is either on the outside somewhere on the cheek, or inside on the buccal side of the mouth. In contrast, the receiver is to be positioned on the lingual or palatal side. In both cases, the position of the transducer and receiver is well defined in a safe and simple way. In most cases, the flexibility of the cheek is sufficient to equalize existing anatomical peculiarities and still be able to achieve coplanarity; if not, it is possible to use a semi-solid gel. It should be noted that the deviations from coplanarity occur only in one dimension, whereas for the Cavitat Ultrasonograph, the deviations occurred routinely in all three dimensions.

The Semi-Solid Gel in new CaviTAU®

A semi-solid gel is placed between the receiver and the alveolar ridge. The sound velocity in this gel should be in the same range as that of soft tissue i.e., 1460 – 1615 m/s, and the gel should have a sound attenuation from 0,3-1,5 dB/cm (1 MHz) so that the acoustical measurements of the properties of the jawbone are not impeded. The haul-off speed for spontaneous resilience should be at most 80 mm/sec.; Appropriate semi-solid gels must be soft, resilient, and flexible so that there is complete contact of the semi-solid gel with the receiver and the alveolar ridge. The absence of air bubbles within the semi-solid gel used can be checked by visual inspection. Because of the flexibility of the gel, it is also possible to adjust the position of the measuring unit without disturbing the contact of the gel and without disturbing the measurements.

The semi-solid property of the gel prevents the gel from disappearing before or during the measurement. Semi-solid gels with such characteristics are commercially available, e.g., the Sonogel Sonokit soft, article number 6510 and 6520, marketed by Sonogel Vertriebs-GmbH in Bad Camberg, Germany. It is a styrenic block copolymer with a hydrogenated midblock of styrene-ethylene/butylene-styrene or styrene-ethylene/propylene-styrene and belongs to the compound class of thermoplastic elastomers. The semi-solid gel can be used and is inserted between the receiver and alveolar ridge to perform the measurements.

For this purpose, a block of the gel is cut at the narrow side to create a little pocket into which the receiver can be inserted using a tiny amount of a lubricant, e.g., the former used ultrasonic gel or water to facilitate the insertion of the receiver. After eliminating any air bubbles between the receiver and the semi-solid gel, the measuring unit is ready for use.

In the case of complicated anatomical conditions, it can be reasonable to use the semi-solid gel on the cheek, i.e., outside of the mouth, as well. This works well for the mandibula, whereas some practical skills are necessary to keep the gel in place for the maxilla. The size of the semi-solid gel piece used should be large enough to accurately cover all relevant parts needed for the measurements.

For hygienic and economic reasons, single-use covers are provided, which advantageously keep the measuring device reusable. Furthermore, the single-use cover does not interfere with the elastic properties of the media. Therefore, as often found in ultrasonic measurements, a non-elastic but flexible plastic film is used. This film is filled inside with a tiny amount of a suitable lubricant, e.g., a usual ultrasound gel, so that the measuring device can move freely inside of the cover. Using another single-use cover is not essential when the flexible cover itself is used as a single-use article. In the new CaviTAU®, one or more light-emitting diodes (LEDs) are provided to improve the receiver’s position recognition (see Figure 5).

Figure 5: LEDs at the enoral ultrasonic receiver

Calibration and functional test

The arrangement of the measuring unit in a defined geometry allows for a straightforward test of the functionality and calibration of the apparatus. Immersing the measuring unit in water completely, gradually moving the unit through the surface of the water, and finally placing the unit entirely in the air while continuously sending ultrasonic signals through the unit allows the assessment of the functionality of the apparatus. Water and air give very different signals, and their expected occurrence, mainly when the measuring unit is moved through the boundary between water and air, allows proof of the correct functioning of the piezoelectric elements. Every time before use, you should perform this check.

Detailed Description of new CaviTAU®

The new CaviTAU® comprises a flexible strip configured to measure a force applied to at least one of the arms, wherein CaviTAU® is configured to indicate the measured strength by visual and/or audible means. Preferably locating a flexible strip in the arm of the apparatus coupled to the ultrasonic receiver prevents excessive force from being applied to the gel interface between the ultrasonic transducer and ultrasonic receiver. In response to the measured force exceeding or falling below one or more predetermined thresholds, CaviTAU® is configured to indicate a reading according to the value of the measured force.

CaviTAU® comprises a multiplexer or means to multiplex the analog signal data generated by the ultrasonic receiver. The means for amplificationand/or multiplexing is preferably located in the arm to which the ultrasonic receiver is coupled and in close to the ultrasonic receiver to improve signal-to-noise ratio i.e. to reduce error.

CaviTAU® comprises a transmitter or means to transmit the multiplexed analog signal data to a discrete main unit that is separate but associated for further processing of the signals. Due to the multiplexing, the amount of transmission equipment from the apparatus to the main unit is beneficially smaller than the number of active piezoelectric elements in the ultrasonic receiver. By multiplexing the analog signal data received simultaneously from a plurality of all the active piezoelectric elements (e.g. 96 elements) in a wired example i.e. when the transmission means comprises a plurality of cables, the apparatus advantageously reduces the number of cables required for transmitting the preprocessed signal data to the main unit (e.g. 8 cables as opposed to 96) and thereby enables serial transmission and processing of the signal data.

CaviTAU® transmits the amplified and multiplexed analog signal data to the main unit associated with the apparatus concurrently with digitalizing the signal data; partially processing the digital signal data; storing the partially processed signal data in memory, and transmitting the partially processed digital signal data to a software application for final processing and subsequent transmission to a display unit associated with the apparatus.

CaviTAU® includes a step displaying the further processed data by associating different signal strengths with: a grayscale comprising different tones, one or more color schemes (see Figure 1 and 2) composed of different colors, and a graph, preferably wherein signal data for straightforward zones are displayed with reduced colored areas. In contrast, data indicating peculiarities are displayed as large areas. Providing one or more grayscale/color schemes aids a user with the recognition of relevant data. Furthermore, displaying the signal data in the form of a graph enables quick analysis. Such a graph can be presented in a 3D format (see Figure 3).

More informations about CaviTAU®