The invention relates to an electric toothbrush having cleaning bristles for personal care, comprising:
means for emitting excitation radiation towards teeth, PA1 means for detecting luminescence return radiation emitted in response to excitation radiation from affected tooth areas, PA1 optical fibre means for guiding the excitation radiation to the proximity of the teeth, PA1 electrical means for imposing on the toothbrush at least one brushing rhythm.
The presence of dental plaque is the major cause of the development of caries. Plaque is formed slowly and systematically on the tooth surfaces between the routine brushing sessions. When brushing is inadequate or is not effected properly the accumulation of dental plaque, particularly in the interdental spaces, promotes the growth of bacteria which can form acids which attack the protective enamel of the teeth and which give rise to dental caries. It is therefore particularly advartageous when dental plaque can be detected and can be removed in order to prevent its accumulation.
Current practice is generally that the dentist tends to dental care of this kind. Indeed, a third person has the fullest opportunity to examine the teeth and to take action where necessary.
Nevertheless, the document WO 92/06671 is known, which relates to a toothbrush with which self-diagnosis as regards the presence of dental plaque is possible. First of all, a substance capable of fluorescing under the influence of excitation radiation is applied to the teeth. This substance has the property that is absorbed selectively by caries and dental plaque. It can be a fluorescent additive mixed with a toothpaste, so that during cleaning of his teeth the user can detect the presence of dental plaque. For this purpose, the toothbrush comprises a light source which emits the excitation radiation, which is guided to the proximity of the teeth by means of optical fibers. Affected zones of the teeth then emit radiation thus induced, which can be detected visually by the user who examines his teeth either by means of a sensor which actuates visual or audible means, which automatically warn the user when dental plaque is detected. To enable detection it is necessary to first rinse the oral cavity and the toothbrush.
However, such a device has several drawbacks. In particular, the sensor is disposed on the base carrying the bristles, so that it is exposed to direct contact with the toothpaste, the fluorescent additive and saliva. Therefore, such an active sensor should be approved for such a use. Moreover, after it has been used for a certain time the sensor may become opaque, for example as a result of a deposited layer, which reduces its detection capability.
Furthermore, the dimensions of the sensor are not negligible, which makes it necessary to provide an area without bristles which is large enough to ensure that the sensor can receive the induced radiation, which has an adverse effect on the cleaning efficiency.
As a result, the arrangement and the dimensions of the radiation sensor make that it picks up the bulk of the induced radiation emitted by the teeth as a whole. Such a configuration does not allow an accurate detection of the areas affected with dental plaque, which areas are generally situated in the interstices and are therefore not readily accessible because they have limited width dimensions of the order of approximately 1 mm. For an effective cleaning of these areas it is therefore necessary to locate them precisely, i.e. separately and not as a whole.
It is obvious that when the toothpaste with its additive has spread in the oral cavity the described method does not allow the detection of dental plaque. As a matter of fact, the whole oral cavity will emit the induced radiation. It is therefore necessary to rinse the oral cavity so as to ensure that the fluorescent additive only settles on the affected tooth areas.
In order to achieve a correct removal of the dental plaque and to ensure an efficient cleaning, it is therefore necessary to repeat a sequence of operations consisting of brushing the teeth with the toothpaste and its fluorescent additive and subsequently of rinsing the oral cavity as well as the toothbrush itself. This constitutes a tedious sequence of operations to be carried out every day.