DENTAL PROSTHESES" Technical Field of the Invention

The object of the present invention is a device for the sterilization of dental screws and prostheses. In particular, the present invention is for application to the sterilization of dental screws and prostheses by photactivation of a surface layer of nanoconstructed titanium dioxide or the like. State of the Art

As everyone knows, when a dentist has to apply a dental screw or a prosthesis on a patient, said screw or prosthesis should be subjected to a sterilization treatment to minimize or eliminate infection risks.

In this case, the dentist, after manually taking out the screw or prosthesis from the package or protective envelope, should place the latter under a UV lamp so as to illuminate the screw and/or prosthesis by the ultraviolet radiation.

When the ultraviolet radiation hits the surface layer, it kills the exposed bacteria and, if the surface layer is coated with nanoconstructed titanium dioxide, it activates the photocatalytic, antibacterial properties of the nanoconstructed titanium dioxide itself. The activation of such properties and the time they remain active depend on how the screws or prostheses are irradiated. In other words, the activation and extent of the surface layer' s antibacterial properties are directly affected by the distance of the screw or prosthesis from the lamp, the inclination thereof to the ultraviolet radiation, the irradiation time, the presence or not of shadow regions, the characteristics of the nanoconstructed surface and of the nanoconstructed titanium dioxide, the exposition of said surface to its interaction with the steam present in the environment, or whatever. Disadvantageously, the ultraviolet lamps presently used and related sterilization techniques, do not ensure the activation of the antibacterial properties of the surface layer and, besides, dentists find them not easy and unpractical to use.

The presently used devices are not, in fact, based on nanoconstructed surfaces, so that they operate only a partial sterilization through radiations in the UV-C wavelength range, whereas in the present device, lamps are used the most part of energy of which is in the range of

300 to 400 Tad, that is, in the of UV-A range.

Moreover, the use of known lamps and techniques do not ensure the activation of said properties in uniform degree over the whole inner surface of screws or prostheses, and they do not ensure either that such properties will remain active for a time interval sufficient to implant the screw or prosthesis hygienically.

Description of the Invention

In this context, the technical task on which the present invention is based is to propose a device for the sterilization of dental screws and/or prostheses which is able to overcome the above cited drawbacks of the prior art.

In particular, one object of the present invention is to provide a device for the sterilization of dental screws and/or prostheses able to ensure the activation of the antibacterial properties of the surface layer of dental screws and/or prostheses all the time.

A further object of the present invention is to propose a device for the sterilization of dental screws and/or prostheses allowing a uniform and sufficiently long-lasting activation of the surface layer of the dental screws and/or prostheses .

The indicated technical task and the specified objects are substantiallv obtained bv a device for the sterilization of dental screws and/or prostheses which has the characteristics set forth in one or more of the attached claims .

Further characteristics and advantages of the present invention will appear more clearly from the indicative, and thus non-limiting, preferred, but non-exclusive, embodiment of a device for the sterilization of dental screws and/or prostheses as illustrated in the accompanying drawings in which:

Fig. 1 is a first perspective view of a device for the sterilization of dental screws and/or prostheses according to the present invention;

Fig. 2 is a second perspective view of the sterilization device shown in Fig. 1;

Fig. 3 is a first perspective view of an alternative embodiment of a device for the sterilization of dental screws and/or prostheses shown in Figs. 1 and 2;

Fig. 4 is a second perspective view of the sterilization device shown in Fig. 3;

Fig. 5 is an exploded perspective view of the device for the sterilization of dental screws and/or prostheses shown in Figs . 3 and 4 and

Fig 6 shows a third embodiment of a device according to the present invention.

With reference to the attached figures, numeral 1 indicates on the whole a device for the sterilization of dental screws and/or prostheses according to the present invention.

The device 1 comprises a container 2 predisposed for holding one or more dental screws and/or prostheses. A cover 3 is removably connected to the container 2 so as to close the latter.

The coupling between the container 2 and cover 3 is- of known type and may be obtained, by way of example, by screwinα or a restrained ioint. nreferablv of reversible type. Advantageously, the coupling between the container 2 and cover 3 is of hermetic type. To this end, at least one gasket (not shown in the figures) is applied between the cover 3 and the container 2.

In the described embodiments, the container 2 is of a substantially cylindrical shape and comprises a tubular section 4, which defines a side wall 5 of container 2, and a plug 6 attached to the tubular section 4 and defining a bottom wall 7 of container 2 (Fig. 5) .

The container 2 and/or cover 3 are made of plastic material which may be also nanoconstructed with suitable nanosolutions (nanoconstructed titanium dioxide or others) and thus made photoactivable and allowing the sterilization of inner surfaces as well. By way of example only, the container 2 and/or cover 3 can be made of polymethylmethacrylate (PMMA) , polyethylene (PE) , polyethylene terephthalate (PET), polyvinylchloride (PVC), polypropylene (PP), etc. In any case, the material used in the construction of the container 2 and/or cover 3 is preferably made opaque to the ultraviolet radiation by the introduction of suitable amounts of mineral substances into the same material.

The device 1 further comprises at least a first ultraviolet ray source 8 associated with the cover 3 able to emit an ultraviolet radiation having the characteristics and wavelength above described and directed toward the bottom wall 7 of container 2.

Moreover, the device 1 comprises at least a second source 9 of ultraviolet radiation having the characteristics and wavelength above described and being associated with the bottom wall 7 of container 2 which emits an ultraviolet radiation directed toward the cover 3 of device 1. The dental screw and/or prosthesis are disposed inside the container 2 between the first 8 and second 9 sources of ultraviolet radiation so as to be fullv and uniformlv irradiated for the activation of the photocatalytic antibacterial proprieties of a nanoconstructed surface coating layer applied on the dental screw and/or prosthesis.

By way of example, such surface coating layer is made up of titanium dioxide or similar in the form of nanometric particles.

Preferably, both the first 8 and second 9 sources are made up of respective light emission diodes (LEDs) .

Such diodes emit ultraviolet radiation having a wavelength ranging between 300 and 400 ran, with an irradiance preferably below 5 W/m ² . However, a higher value would not be detrimental to the correct operation of the invention.

According to the embodiment illustrated in Figs. 3, 4 and

5, the device 1 comprises a single first source 8 and a single second source 9 disposed coaxially to a longitudinal axis ^λX A" of prevalent development of device 1.

Advantageously, the device 1 comprises a plurality of sources 8 uniformly disposed in correspondence of the cover

3, and a plurality of second sources 9 uniformly associated with the bottom wall 7.

Advantageously, the first sources 8 and second sources 9 are disposed with axial symmetrical configuration relative to the longitudinal axis "A" of prevalent development.

In the embodiment shown in Figs. 1 and 2, the device 1 comprises four first sources 8 and four second sources 9.

The device 1 further comprises a support body 10 fixed to the bottom wall for bearing the second sources 9 of ultraviolet radiation.

The support body 10 is a panel, preferably made of plastic material, resting against the plug 6 and bearing either the second sources 9 (Fig. 2) or the single second source 9, as in the case of the embodiment shown in Figs. 3, 4 and 5.

Besides, the device 1 comprises a further support body 10' fixed to the cover 3 and ant to support either the first sources 8 of the embodiment shown in Fig. 2 or the single first source 8 of the embodiment shown in Figs. 3, 4 and 5.

With reference to the embodiment shown in Figs. 3 and 4, the device 1 further comprises at least one protective shield 11 located above at least the second source 9 of ultraviolet radiation. A further protective shield 11' is associated with the cover 3 for protecting the first source

8 of ultraviolet radiation.

In the embodiment of Fig. 1 no protective shield is illustrated. However, also such device may include a protective shield overlying the plurality of second sources

9.

In any case, a bearing plane "P" is defined in the device 1 onto which the dental screw or prosthesis to be sterilized is made to rest.

In the case of the embodiment shown in Figs. 1 and 2, the bearing plane "P" is defined by the support body 10. In other words, the dental screw or prosthesis is made to abut onto the support body 10 between the second sources 9.

In the case of the embodiment shown in Figs. 3 and 4, the bearing plane "P" is defined by the protective shield 11 made of plastic or glass material which is transparent to the UV rays and on which the screw or prosthesis to be sterilized is made to rest.

According to the present invention, the distance between the bearing plane ^W P" and the first source (or first sources) 8 ranges from 1.0 and 3.5 cm, preferably from 1.5 and 3.0 cm.

With reference to the embodiment shown in Figs. 3 and 4, the distance between the bearing plane ^NX P" and the second source 9 is from 0.2 and 1.2 cm, preferably from 0.5 and

1.0 cm.

The device 1 further comprises power supply means 12 for the first and second sources 8, 9 of ultraviolet radiation.

In the illustrated embodiments, the supply means 12 comprise a connector 13 able to be associated with a socket

14 formed on the cover 3 of device 1.

In this case the power supply is ensured by an electric alternate current from the mains, said current being possibly transformed for application thereof at the desired voltage.

Alternatively, the supply can be ensured by a direct current, possibly from a battery (not shown in the attached figures) .

The supply means 12 further include an electric connection

(not shown) which connects the first sources 8 to the second sources 9.

A switch 15 allows the user to turn on/off the device 1. In the described embodiments, the switch 15 is located on the cover 3.

The device 1 further comprises a timer (not shown) associated with the first and second sources 8, 9 so as to activate and/or deactivate the latter according to predetermined time intervals, as necessary to properly activate the photocatalytic antibacterial properties of a coating surface layer applied on the dental screw and/or prosthesis.

The device can possibly comprise LEDs-cooling systems both of active type (fans or the like) and passive type

(conduction or natural convection-operating heatsinks, etc. ) .

The device 1 according to the present invention can be used for the sterilization of dental screws and/or prostheses taken out from their package.

Moreover, such device 1 can be used for the sterilization of dental screws and/or prostheses to be closed again within suitable protective plastic envelopes (blisters) .

In this case, the plastic material which the envelope is made of is transparent to the ultraviolet radiation.

With reference to figure 6 there is shown a third embodiment of a device 1 for the sterilization according to the present invention.

In particular, in this embodiment, the bearing plane "P" is housed in one or more drawers 16 extractable from a respective seat 18 of container 2.

Inside of each drawer 16 may be inserted one or more screws and\or prostheses inside blister 19 or extracted from its packaging and resting directly on the plane "P". Advantageously, the embodiment of figure 6 comprises an active fan-cooling system 17 to avoid any overheating of the lighted sources 8, 9 and of the whole device 1. The invention reaches the envisaged objects and obtains major advantages.

In fact, since the dental screws and/or prosthesis is applied between the first and second sources of ultraviolet radiation, it is reached most efficiently by the same radiation, so that the activation of the photocatalytic antibacterial properties of the coating of titanium dioxide applied on the screw and/or prosthesis is ensured. Moreover, the location of the source (s) of ultraviolet radiation allows a uniform illumination of the screw and/or prosthesis by avoiding shadow regions, so that also the activation of the antibacterial properties results uniform on the surface of same screw and/or prosthesis. Again, the fixed distance between the screw and/or prosthesis makes it possible to standardize the sterilization process, thereby obtaining conditions and duration of sterilization as far as possible uniform and constant, also in relation to the duration of the timer- assisted irradiation step.