Apparatus for diagnosing periodontitis

An apparatus for diagnosing an inflammatory condition relating to periodontitis made up of a probe with sensors for measuring temperature within a periodontal pocket. The apparatus further comprises a graduated scale for measuring the depth of the periodontal pocket. Also provided is equipment for recording the temperature difference between the bottom and the mouth of the periodontal pocket.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an apparatus or diagnosing inflammatory 
conditions in connection with periodontitle, and the invention also 
involves a process for such diagnosis. 
2. Description of Related Art 
The loosening of teeth (periodontitis) is a bacterially caused inflammation 
in the attachment apparatus of the tooth (periodontium) which, if left 
untreated results in decomposition of the bone around the tooth 
(resorption) and of the tooth loosening its anchorage, the anchorage being 
ultimately lost. Periodontitis shall primarily be prevented by good oral 
hygiene but may also, after being established, be treated. This treatment 
will mainly be directed to interrupt the progress of the disease. 
Practically all adults are to a greater or lesser degree subjected to the 
disease, and approximately 10% of the population in the industrialized 
world develop severe periodontitis resulting in partial or total loss of 
the teeth. 
Periodontitis is initially a disease which to the patient lacks symptoms. 
However, the dentist can see early signs of an incipient disease 
development. The gum around the teeth become red, swollen and bleed 
easily, i.e. show signs of an inflammation. Simultaneously the pocket 
between tooth and gum will be subject to increased depth. In this pocket 
additional bacteria will accumulate and proliferate (plaque). Gradually 
the bacteria will calcify and calculus will form on the teeth. 
Synchronously with the formation of plaque the inflamation spreads in the 
attachment apparatus of the tooth and the bone surrounding the root of the 
tooth starts to decompose. 
The methods available to the dentist to diagnose periodontitis is measuring 
the depth of the periodontal pocket around the tooth and registering the 
tendency for bleeding connection herewith. However, this does not give a 
full measure of the degree of inflamation in the attachment apparatus of 
the tooth. Above all these measures give little guidance for judging how 
the disease will develop. They rather reflect what has already taken 
place. 
One of the greatest problem in the treatment of periodontitis is to be able 
to predict around what teeth the periodontitis activity will increase. It 
has been found that the loss of supporting tissue around the teeth in 
periodontitis fluctuates, i.e. periods of low disease activity succeed 
periods of high activity. Early signs of this can be seen in the degree of 
inflammation in the environment of the teeth. An incipient increase of the 
degree of inflammation should be treated as soon as possible in order to 
save as much as possible of the anchorage of the tooth. The traditional 
methods (depth of periodontal pocket and bleeding tendency) in order to 
estimate this condition are not reliable. A deep periodontal pocket does 
not necessarily mean that the periodontal process is active. A healing 
process may have started in the same manner a shallow periodontal pocket 
may not mean that the periodontal disease is inactive. Also a deep pocket 
has once been shallow and it is very important to be able to predict which 
periodontal pockets are subject to deepening. 
The cardinal symptoms of a topical inflammatory condition is calor 
(temperature increase), dolor (pain), rubor (redness) and tumor 
(swelling). Out of these the redness (bleeding in the periodontal pocket) 
and the swelling (in combination with decomposition of alveolar bone, i.e. 
measuring depth of periodontal pocket) have traditionally been used to 
diagnose periodontitis. However, these symptoms of periodontitis are not 
reliable measures for estimating the activity of the disease. Furthermore, 
it is not possible to estimate bleeding quantitatively. These traditional 
methods, measuring of pocket depth and bleeding tendency, to judge the 
activity of the periodontal process often give misleading results, 
particularly in an early stage of an active period. A deep periodontal 
pocket which is bleeding does not always mean that the process is active. 
The use of temperature as a measurement for the activity of periodontitis 
is based on the fact that an inflammatory process in view of increased 
flow of blood results in an early temperature increase (before the depth 
of the periodontal pocket has increased). However, in the mouth the 
temperature varies between different areas. The gum is warmer the deeper 
in the oral cavity the measurement le made (32.degree. C. to 37.degree. 
C.). An absolute temperature scale to estimate the degree of inflammation 
is thus not possible to define. However, the surface temperature in the 
opening of the periodontal pocket is not affected by a possible 
inflammation at the bottom the periodontal pocket. 
SUMMARY OF THE INVENTION 
The present invention has for an object to provide an apparatus by means of 
which inflammatory conditions in connection with periodontitis can be 
diagnosed in a simple and reliable manner. 
Another object of the invention is to provide a process for diagnosing the 
degree of inflammatory condition connection with periodontitis, which 
process is based on an estimation of the exterior conditions around a so 
called periodontal pocket. 
For these and other objects which will be clear from the following 
disclosure the invention provides for an apparatus for diagnosing 
periodontitis in view of its inflammatory aspect, said apparatus 
comprising means for measuring and recording temperature in connection 
with a periodontal pocket. The apparatus for such diagnosis is provided 
with a measuring means with a graduated scale for measuring the depth of 
the periodontal pocket and in association herewith also provided with 
means for measuring and recording the temperature difference between the 
bottom and the mouth of the periodontal pocket. 
The apparatus means for temperature measurement suitably constituted by a 
probe which is connected to the measuring means in such a manner that the 
depth of the periodontal pocket can be recorded in connection with 
measuring the temperature at its bottom. 
The temperature sensor or transducer, which is suitably positioned at the 
free end of the probe, can be of different types, of which examples are 
thermoelements, thermistors, semiconductor diodes and resistance 
transducers. 
In a particularly preferred embodiment of the apparatus according to the 
present invention the probe and the measuring means are assembled to one 
unit. In an alternative embodiment of the apparatus according to the 
invention said means for temperature measurement may comprise a probe with 
two transducers displacable relative to each other, the apparatus also 
including a measuring means with a graduated scale for measuring the depth 
of the periodontal pocket. One end of the probe being permanently 
connected to the measuring means at its free end, whereas the other 
transducer is movable along the scale so that the temperature difference 
between the bottom and the mouth of the periodontal pocket can be 
registered at the same time as the pocket depth is measured. 
It is obvious for a man skilled in the art that the temperature 
simultaneously can be monitored at various levels of a tooth pocket by an 
array of sensors, or transducers. 
The invention also provides for process for diagnosing inflammatory 
conditions in connection with periodontitis, said process being based on 
considering the exterior conditions around a so called periodontal pocket. 
This process comprises the steps: 
a) measuring the depth of the periodontal pocket, i.e. the distance between 
the bottom and the mouth of the pocket; 
b) measuring the temperature difference between the bottom and mouth of the 
periodontal pocket; and 
c) determining-the degree and development of the periodontitis in 
dependence of the parameters measured under step a) and step b). 
In connection with the techniques according to the present invention it can 
be generally said that a temperature increase at the bottom of the 
periodontal pocket, more precisely a temperature difference of more than 
about 0.5.degree. C. between the mouth and bottom of the periodontal 
pocket, constitutes an early sign of the fact that the periodontal process 
is entering an active stage. A temperature difference of more than about 
1.degree. C. shows that the process is established. The present invention 
thus provides for reliable diagnostic techniques which are based on 
simultaneous measurement of the temperature difference between the bottom 
and the mouth of the pocket and the depth of the pocket, and through said 
techniques one may thus verify whether the periodontal process resides in 
an active stage and whether said process is established.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
EXAMPLE 1 
FIG. 1 shows diagrammatically the structure of the instrument in the form 
of a block diagram. In principle, the instrument consists of a manually 
held measuring transducer 1, which via a cable is connected to a recording 
unit consisting of an amplifier with filter 3, computer 5, display 7, 
printer 9 and a device 11 for voltage supply. In the amplifying unit 3 the 
amplification is adjusted in such a manner that a suitable signal size is 
obtained to computer 5. Said computer 5 is of a conventional type and can 
be constituted for example by a Zilog Z80 with associated operational 
circuits and programable memory. In this non-limiting example there has 
been chosen as a display 7 a liquid crystal display, since such device 
consume substantially less energy than a corresponding display of the 
light emitting diode type. If, however, the instrument is directly 
mains-connected this latter type of better readability can advantageously 
be used. 
The voltage supply unit 11 may consist of a rechargable system with 
nickel-cadmium cells and associated charger. However, the instrument may 
also be connected directly to the mains. In both cases the voltage unit 
contains suitably arranged control circuits stabilizing the voltage 
through the other part of the electronic equipment. 
In FIGS. 2 and 3 the manually held measuring probe 1 is shown more in 
detail. The measuring probe 1 in principle consists of a probe 13 attached 
to a handle 15 and the free distal end 17 which is shown in enlargement in 
FIG. 3. This free end 17 is at its tip provided with a temperature sensor 
or transducer 19 which through electrically leading cables 21 is connected 
with the recording unit of the instrument as described in connection with 
FIG. 1. The free end 17 of the probe 13 is further provided with markings 
23 enabling measurement of the depth of the periodontal pocket. 
According to FIG. 2 the measuring probe is provided with a switch for 
activating the instrument. 
The function of the instrument described is briefly the following. 
The measuring probe 1 is placed with the free end 17 of probe 13 placed in 
the periodontal pocket which is subject to diagnosis, sensor or transducer 
19 being positioned adjacent to the bottom of the pocket. The electronics 
are then activated by means of a switch 25. The temperature which is 
registered at the bottom of the periodontal pocket is measured by the 
computer, and when the signal has been stabilized the level is recorded 
and the operator is correspondingly informed for example by a short sound 
signal. The measured value can then as the case may be be registered with 
printer 9. 
Then the measuring probe 13 with its free end 17 and sensor or transducer 
19 is moved to the mouth of the periodental pocket and the measuring 
procedure is repeated. By means of computer 5 the difference between the 
two temperatures measured is now calculated, said difference being shown 
on the display 7 of the instrument and may also be registered by printer 
9. 
In connection with measuring the temperature at the bottom of the 
periodental pocket also the depth of said pocket is measured by means of 
the scale or marking 23. 
By correlating the temperature difference measured and the depth of the 
periodontal pocket information whether the periodental process is moving 
into an active stage and whether the process is established will be 
obtained in a simple manner. In accordance with the result obtained a 
suitable treatment regime can then be instituted. 
In an alternative embodiment of the apparatus according to the invention 
the means for temperature measurement may comprise a probe 13 with two 
transducers 19,19' displaceable relative to each other. The apparatus also 
includes a measuring means with a graduated scale 23 for measuring the 
depth of the periodonal pocket, one end of the probe being permanently 
connected to the measuring means at its free end, whereas the other 
transducer 19' is movable alone the scale so that the temperature 
difference between the bottom and the mouth of the periodontal pocket can 
be registered at the same time as the pocket depth is measured. 
EXAMPLE 2 
The block diagram in FIG. 4 shows another preferred embodiment of the 
apparatus according to the present invention of the apparatus according to 
the present invention. The temperature probe with its sensor 31 is 
connected via a cable to an electronic unit 32 consisting of an amplifier 
with filter, computer and power supply. The temperature probe has a 
build-in-activator for registration of eventual bleeding in the tooth 
pocket. The display 33 unit as shown in FIG. 5 is connected via a cable to 
the electronic unit. The display has two groups 40,41 of figures. One 40 
for indication of the number of the tooth and another 41 for the display 
of the temperature difference between the mouth of the periodontal pocket 
and the bottom. Furthermore, there is an array of indicators to show the 
position in the tooth pocket and a reset-switch 42 to be able to start the 
measurements from the beginning. The registration of the temperature is 
activated by a footswitch 34. 
As seen in FIG. 4 a remote display 35 and/or a printer 36 is also available 
to connect to the electronic unit. 
The measuring procedure is as follows: 
1. Press the "reset" button. 
2. The probe 31 is placed into the bottom of the tooth pocket. 
3. Activate the footswitch 34. 
4. When a low frequency signal is heard the measurement procedure is 
completed. 
5. Move to the mouth of the tooth pocket. 
6. Activate the footswitch 34. 
7. When the measuring period is completed a high frequency signal is heard. 
8. The display shows the temperature difference and the indicator moves 
automatically to the next measuring site. 
Registration of bleeding can be performed for the measured position by 
activating the probe. An indication 43 will appear on the display. 
The advantage with this embodiment is that the probe could be held more 
firmly since the measurement is activated by the footswitch. 
EXAMPLE 3 
Example of Registration Correlated to the Development of Periodontitis 
FIG. 6 shows registrations of the initial temperature difference between 
the bottom and the mouth (t.sub.d) of 30 periodontal pocket at the initial 
stage 30 periodontal pockets distributed among 4 patients and the 
subsequent change in anchorage of the tooth at the respective periodontal 
pocket measured after five months (a.sub.d). The teeth around which the 
registrations have been made have all diagnosed periodontitis. A positive 
value of a.sub.d means that the attachment has increased, whereas a 
negative value means loss of attachment, i.e. the periodontitis has 
progressed. Values of t.sub.d &lt;0.5.degree. C. in the initial stage are 
seen only for periodontal pockets where a gain or no change of the 
attachment of the tooth has been registered. Average a.sub.d in the range 
is 0.46 mm, i.e. a gain of attachment. Values of t.sub.d 
.ltoreq.0.5.degree. C. but &lt;1.0.degree. C. have often resulted in a loss 
of tooth attachment. Average f.sub.d in said range is -1.00 mm. The most 
serious losses of tooth attachment are seen for t.sub.d 
.gtoreq.1.0.degree. C. having an average a.sub.d in the range of -2.75 
mm, i.e. the periodontitis has developed. 
EXAMPLE 4 
FIG. 7 shows registrations of the initial temperature difference between 
the bottom and the mouth of 35 periodontal pockets (t.sub.d) distributed 
among 6 patients and the subsequent change in anchorage of the tooth at 
the respective peridontal pocket (a.sub.d) measured after 2 months. Only 
periodontal pockets with a temperature difference of more than 0.5.degree. 
C. (t.sub.d &gt;0.5.degree. C.) were selected. After registration of t.sub.d, 
they were given hygiene treatment with subgingival scaling. After 2 months 
change in periodontal anchorage was registered (a.sub.d). By the treatment 
these periodontal pockets, which would have lost periodontal attachment 
according to Example 3 because of active periodontitis as Indicated by 
t.sub.d &gt;0.5.degree. C. instead gained or maintained their original level 
of anchorage, as an average a.sub.d =0.77 mm.