WO2008071837A1

WO2008071837A1 - Dental instrument

Info

Publication number: WO2008071837A1
Application number: PCT/FI2007/050659
Authority: WO
Inventors: Kari Lehtonen
Original assignee: Lm-Instruments Oy
Priority date: 2006-12-08
Filing date: 2007-12-05
Publication date: 2008-06-19
Also published as: FI20061093L; JP2010511456A; EP2097037A1; FI20061093A0

Abstract

The present invention relates to a dental instrument, which comprises a handpiece (10) and a tip part (11) joining to the handpiece (10). A modelling part (12) protruding from the tip part (11) is fixedly or detachably connented to the tip of the second end (112) of the tip part, or in the essential proximity of it, the modelling part (12) being arranged for modelling tooth filling material and to be translucent or to comprise a translucent component. A means for generating light (15) used at least for curing tooth filling material is arranged at the tip part (11) or the modelling part (12) joining to it. Dimensions and forms of the tip part (11), at least at the essential proximity of the second end (112) of the tip part (11), or dimensions and forms of the second end (112) of the tip part (11) itself are arranged such that when the instrument is observed at its position in the patient's mouth regarding operating on one of the premolars or molars, the second end (112) of the tip part (11) or a part of the tip part (11) locating at the essential proximity of the tip part (11) only partially blocks a view to the premolar or molar in question.

Description

DENTAL INSTRUMENT

Field of the invention

This invention relates to a dental instrument according to the preamble of claim 1, to be used especially in connection with repairing cavities of teeth.

Background of the invention

Traditionally, various metallic materials or materials containing metal have been used to repair cavities of teeth. Since the potential health hazards of especially amalgam have been realized, of the substitute materials light curable polymers have emerged, which typi- cally contain at least one monomer and one light sensitive material (e.g. Camphorquinone) catalysing the polymerisation reaction of the monomers .

The absorption spectrum of light sensitive materials is usually quite narrow, typically much narrower than that of the incandescent and halogen lamps generally used as light sources in traditional light curers. Efficiency of these lamps having a wide emission spectrum in view of producing radiation relevant to curing is thus already basically quite low and the intensity is further decreased upon their ag- ing or when damaged, which may even become a risk in view of successful curing of the material to be polymerised.

Because of the substantial amount of space needed for the light source and reflector constructions, many of the prior art light curers are of impractical design and, neither has it been possible to construct them as consistent with other instruments used for dental treatments. Then, also placing of them e.g. on the instrument table of a dental care unit is somewhat difficult. When devices are used within a mouth of a patient, their great dimensions hamper the work and, especially, block view to the subject being operated on.

In order to be able to utilize the electrical energy used for generation of light to the production of specifically those wave lengths which are effective in respect of curing, one has begun developing such light curing devices which include as light source coπponents, among others, light emitting diodes, or LEDs. Typically, both in this kind and in the solutions as described above utilising lamps, the light is produced in the body part of the device and the radiation received from the light source or sources is guided to the object through the tip part of the device with the help of a light conductor, such as an optical fiber. Light curing devices containing LED groups and in which the tip of the device is formed of an elongated and bent light conducting element which extends essentially parallel with the body of the device are presented e.g. in the DE patent publication 199 43 393 and in the WO publication 00/13608.

There always are problems of their own relating to the use of light guides, especially bent light guides. For example, in the device according to the figures of the abovementioned DE publication, one is not able to direct all the light generated at the T₁KDs to the object since the laws of physics dictate that out of the beams originating from the light source and arriving at the light guide only those with a smaller than a specific angle of arrival will start travelling in the fiber, whereas those arriving at an angle greater than that will escape from the fiber. Moreover, the translucency of the fibers which easily break and crack is typically of the order of 60 % for the most even when undamaged.

In view of losses of light intensity, it would of course be natural to place the light source as close to the object to be cured as possible. Hence, e.g. the US patent publication 6,159,005 teaches that a light source preferably being made up of laser diodes may be placed essentially at the tip of a light curing device. In the US patent publication 5,634,711, too, a corresponding basic solution is discussed in which semiconductor means emitting light is proposed to be placed at the tip of a tip part which possibly comprises a joint or equivalent, in which case the optical fibre may be replaced with an optical "cork", such as a TIR lens which collimates the light received from the LEDs. It has been typical to use so-called plugger and modelling instruments with steel tips for modelling tooth filling material. Such instruments generally comprise a hand piece and a modelling tip attached thereto. Plugger instrument and light curer are used in con- nection with tooth filling by first modelling filling material in a tooth cavity with the modelling instrument and thereafter curing (hardening) the material with help of the light curing device. Especially, when one uses a so-called small-batch technique in which one tries to minimize problems caused by shrinkage of the material, the filling operation includes several successive modelling and light curing stages. Then, working is somewhat awkward and slow as one must repeatedly use in turns first the modelling instrument and thereafter the light curing device. Two handed work, especially, is then slow and as far as four handed work is concerned, use of the light curer disturbs assistant's other tasks or postpones them.

Prior art also knows dental instruments used for curing filling material and in which light is directed to filling material through such an element locating at or extending to the tip of the instrument that in principle at least could also be used for modelling filling material. Yet, in the solution according to the US patent publication 5,098,292, for example, a significant portion of the intensity of light generated by the device is lost as a consequence of the sharp bends of the light guide.

The US patent application 2003/0186195 presents a number of various modelling parts meant to be placed at the tip of an instrument and considered suitable for e.g. light curing use. To some extent, also dimensions of the modelling parts are discussed in the publication. One may wonder that since the invention according to that publication is directed at materials applicable for use in these modelling parts, if this is the reason for the document teaching nothing concerning construction of a complete instrument that comprises such a modelling part. In the publication, only structures of the modelling part are discussed while as far as construction of the actual instrument is concerned, only one schematic figure is presented and in the text passage which relates to it one states "It should be understood that the elements in the figures are representational, and are not drawn to scale in the interest of clarity" .

The US patent publication 6,702,576, too, pays no attention to the dimensions of a light curing device e.g. from the perspective of how the design and the dimensions of the instrument possibly hamper the view to the subject being operated during the work while the instrument is in its operating position in the patient's mouth, especially when operating on the molars which are awkward regarding visibility. For the background to this visibility problem it could be mentioned, for example, that on average, typical dimensions of women's first lower premolar (the 4^th tooth) are about 7,8 mm x 7,1 mm and about 11 mm x 10,5 mm for the "lower sevens".

Brief description of the invention

The object of the invention is to come up with a dental instrument especially for use for both modelling and curing of tooth filling material by which one will be able to lessen many of the abovementioned problems of the prior art instruments. Especially, the object is to lessen the need to stretch and/or to bow down for seeing the subject being operated on which lies behind the instrument despite that the light source is placed substantially close to the subject being operated, that is in the essential proximity of the tip of the instru- ment, to enable a good light guiding efficiency. Also, the object of the invention is embodiments that may be realized without a need for using special materials more expensive than accustomed yet still creating a rigid enough construction considering the intended use of the instrument.

What is essential for the instrument according to the invention is the combination of features presented in the attached claim 1. Some preferable embodiments of the invention are presented in the attached dependent claims.

The construction of an instrument according to the invention thus includes a handpiece and at least one tip part joining to the hand piece and consisting of at least one part comprising a first end and a second end. The first end of the tip part is fixedly or detachably attached to the handpiece and the tip part is arranged to consist of a construction which coirprises a modelling part fixedly or detachably attached to the tip of the second end of the tip part or in the es- sential proximity of said tip and protruding from the tip part, the modelling part being arranged for modelling tooth filling material and to be translucent or to include a translucent component. Arranged at the tip part or the modelling part joining to it there is a means for generating light used at least for curing tooth filling material. The dimensions and forms of the tip part, at least at the essential proximity of the second end of the tip part, or the dimensions and forms of said second end of the tip part itself are arranged such that when the instrument is observed at its position in the patient' s mouth regarding operating on one of the premolars or molars, i.e. from an angle with respect to a central axis of said tip part, or, from the direction the person performing the operation sees the instrument at such an instant, said second end of the tip part or said part of the tip part lying at the essential proximity of the tip part, only partially blocks a view to the premolar or molar in ques- tion. Preferably the instrument as a whole is realized such that when the instrument is at that position, none of its parts at least completely blocks the view for the person performing an operation to the premolar or molar being operated on.

It is possible to work both ergonomically and efficiently with an instrument according to the invention. When the instrument comprises both a modelling part for filling material and a means for generating and delivering light to the subject being cured with high efficiency, that is means both for modelling filling material and for curing it, and when not only the actual technical function of the instrument but also visibility to the subject to be worked on has been taken into account in its design, especially visibility to the problematic molar area, performing a tooth filling operation is relatively easy even without an assisting person. As an example of the opportunities the instrument provides the operation typically awkward for the dentists can be mentioned when light curable materials are used in which a contact is created between two teeth, regarding which operation the invention provides the possibility simultaneously and with the one and the same instrument both to cure the filling material and to press on a desired target in the operating area.

The instrument according to the invention and especially one accord- ing to its preferable embodiments makes possible taking the component emitting the curing wave length close to the subject in patient's mouth which is to be cured and thus directing light to the target at high efficiency. Thereby, success in the curing is more reliable than e.g. with many prior art instruments upon use of which a significant distance remains between filling material lying at the bottom of a tooth cavity and the light curing head. The invention together with its preferable embodiments also makes possible, for example, realization of the parts used for modelling filling material as detachable and disposable yet as relatively inexpensive. The invention makes em- bodiments possible in which regardless of certain short dimensions of the instrument, a rigid enough structure may be achieved which still may be realized by using relatively inexpensive materials and manufacturing techniques customary in the field.

The invention also makes possible realization of a modelling-curing instrument such that as far as its shapes are concerned, it corresponds with the other instruments typically kept in an instrument holder of a dental care unit, whereby in the dental care environment one may place it on the instrument console of a dental care unit. Re- alization of the instrument in accordance with a preferable embodiment of the invention as essentially cylindrical instead of as pistol-like also makes possible using the light curing-modelling instrument according to the invention with similar grip as the other typical dental care instruments. Such an instrument takes much less space on an instrument tray often used in dental care environment than many of the prior art light curing devices.

Brief description of the figures

In the following the invention, its special features and other advantages one may achieve by the invention are discussed more closely with the help of some preferable embodiments of the invention and also referring to the attached figures. However, the invention is not intended to be limited solely to just these embodiments. It could also be mentioned that, regarding this application, when instrument's horizontal and vertical dimensions are discussed a position of the instrument is referred to in which an essentially elongated instru- ment and/or its essentially elongated tip part extends essentially horizontalIy.

Of the attached figures, which are not meant to be taken as a dimensioned drawings,

Fig. 1 presents a basic construction for an instrument according to the invention,

Fig. 2 presents a second embodiment of the instrument as seen from the side and in which the central axis of a handpiece and the central axis of a tip part is arranged at an angle with respect to each other,

Fig. 3 presents a third embodiment of the instrument as seen from the side and in which the direction in which the modelling part of the instrument extends from a tip part is arranged to deviate from orthogonal,

Fig. 4 presents a fourth embodiment of the instrument seen from the side in which location and size of a modelling part of the instrument with respect to a handpiece is centered and

Fig. 5 presents one preferable embodiment of the invention as seen from above.

Detailed description of the invention

Fig. 1 presents a basic construction of a dental instrument (1) according to the invention, which comprises a handpiece (10) and a tip part (11) joining to it and comprising a first end (111) and a second end (112) . The first end of the tip part (11) joins to the handpiece (10) and at the end of the second end (112) of the tip part, or at its essential proximity, a translucent modelling part (12) joining to the tip part (11) is arranged which is intended for modelling filling material. In the embodiment according to Fig. 1, the handpiece (10) is elongated and its central axis is arranged to be essentially parallel with the central axis of the tip part (11) , but the handpiece (10) may be of some other shape as well.

A means for generating light (15) not shown in Fig 1. is arranged at the essential proximity of said second end (12) of the tip part (11), such as at the essential proximity of the modelling part (12), pref- erably into the modelling part (12) itself. There may be different light sources for different purposes of use and they may be arranged for optional use, but at least one light source is arranged to generate light to be used for curing tooth filling material, typically substantially blue light. In the case of more than one light source (15) , one of them may be arranged to generate white light which may be used as help in diagnostics. A switch (16) for using the light source (15) or light sources is arranged to the instrument, in the embodiment presented in Figs. 1-5, to its handpiece (10) .

The modelling part (12) may be arranged as hollow and/or to comprise a light guiding and/or a light refracting structure. In the embodiment according to Fig. 1 also a separate translucent component, a modelling head (14) , is arranged to the modelling part (12) . The modelling head (14) , such as also the light source (15) arranged to the modelling part (12) , for example, such as one T.FD or more, may be realized as detachably connected. The connection of the modelling head (14) to the modelling part (12) may be realized through a fixing element (13) arranged between the two, or without a fixing element by a male-female structure. Said one or more LED is preferably arranged as changeable together with the modelling part (12) or as integrated with a detachably connected "tip + modelling part" .

The size of the modelling part (12) is preferably arranged to be such that in the direction it protrudes from the tip part (11) , the great- est diameter of any cross section of the modelling part (12), or the length of the longest side of a cross section, is about 11 mm for the most, such as about 8 mm for the most, preferably about 7 mm for the most. In one preferable embodiment of the invention, such greatest measure of the diameter of the modelling part is arranged essentially in the area of the base of the modelling part (12) and the modelling part (12) to become narrower towards its tip. The protruding direction in this context may also be understood as the direction which is essentially parallel with the central axis of the modelling part (12).

The dimensions of cross sections of the tip part (11) of the instrument at least essentially at said second end (112) of it, and pref- erably also at the immediate proximity of this second end (112) are preferably arranged to be smaller than dimensions of the cross section of the handpiece (10) joining to the first end (111) of the tip part (11) . On the other hand, it is also preferable to arrange dimensions of the cross sections of the tip part (11) at least essentially at said second end (112) of it smaller than the greatest dimension of the greatest cross section of the modelling part (12) - and/or of the connecting element (13) for the modelling part arranged thereto - arranged at this second end (112) of the tip part (11) . The dimensions of the tip part (11) at its joining point to the modelling part (12) , especially when the tip part (11) joins to the modelling part (12) at its side, are preferable to be arranged smaller than the dimensions of the modelling part (12) at this joining point. At least the horizontal dimension of the cross section of the second end (112) of the tip part at its joining point to the modelling part (12) is prefera- bly arranged smaller than the dimensions of the cross section of the modelling part (12) at this joining point.

Concerning visibility to the subject being operated on especially the horizontal dimensions of cross sections of the tip part (11) are most relevant. To make the structure strong and rigid enough, considering those forces acting on the instrument (1) in connection with its use for modelling which the tip part (11) of the instrument must stand up to as essentially stable, in preferable embodiments of the invention the dimensions of the cross sections of the tip part (11) mentioned above are horizontal dimensions of the cross sections of the tip part

(11) . The vertical dimensions of the cross sections of the tip part (11) may even be greater than the horizontal ones, especially essentially at the second end (112) of the tip part (11) . Fig. 5 shows the instrument as seen from above, and comparison of this top view to the side views presented in Figs. 1-4 demonstrates how the width of the tip part (11) at its second end (112) where the modelling part (12) is located may be arranged smaller than the height of the correspond- ing point, that is the vertical dimension of the cross section in question.

According to one preferable erribodiment of the invention the tip part

(II) is designed such that when moving from the second end (112) of the tip part towards its first end (111) , all the dimensions of the cross sections of the tip part are always as great or greater than the corresponding dimensions of the previous cross section, i.e. the tip part (11) is arranged to smoothly thicken towards its first end

(III) (cmp. Fig. 2) .

According to one preferable embodiment of the invention the tip part (11) is thus realized such that essentially in the area of its second end (112), at least the horizontal dimension of the cross section of the tip part is arranged smaller than the vertical dimension of the cross section in question. In any case, dimensions and forms of said tip part (11) , at least at the essential proximity of the second end (112) of the tip part (11) , or the dimensions and forms of said second end (112) of the tip part (11) itself are arranged such that when the instrument is observed at its position in the patient's mouth re- garding operating on one of the premolars or molars, i.e. from an angle with respect to the central axis of said tip part (11) , or, from the direction the person performing the operation sees the instrument at such an instant, said second end (112) of the tip part (11) or said part of the tip part (11) lying at the essential proximity of the tip part (11) only partially blocks a view to the premolar or molar in question.

According to one preferable embodiment of the invention the shapes and dimensions of the instrument are realized such that when the in- strument is observed from the direction of the handpiece (10), i.e. from the direction the person performing the operation sees the instrument, especially, when the instrument is at its operating position in a patient's mouth regarding filling of a premolar or a molar, the modelling part (12) arranged at the tip part (11) of the instrument does not completely at least block view to the premolar or molar in question.

According to one preferable embodiment of the invention the shapes and dimensions of the instrument are realized such that when the instrument is observed from the direction of the handpiece (10), i.e. from the direction the person performing the operation sees the instrument, especially, when the instrument is at its operating posi- tion in a patient's mouth regarding filling of a premolar or a molar, the instrument (1) does not completely at least block view to the premolar or molar in question.

In an instrument according to Fig. 1, the handpiece (10) is thus ar- ranged to comprise or consist of an essentially elongated piece and the tip part (11) to become as essentially parallel with the handpiece (10) . Observing the handpiece (10) from the side, the central axis of the handpiece (10) and the central axis of the tip part (11) may, however, be arranged at an angle with respect to each other, as presented in Fig. 2.

Preferably, at least at said second end (112) of the tip part (11) the width (or diameter) of the cross section of the tip part (11) on a plane which is at right angles to a plane comprising the protruding direction of the modelling part (12) is arranged smaller than 8 mm, such as smaller than 5 mm.

According to one preferable embodiment of the invention the handpiece

(10) comprises an essentially elongated part or forms as a whole an essentially elongated part. Preferably, the modelling part (12) or its tip and/or the modelling head (14) arranged at the modelling part

(12) is centered to locate within an extension of a cylindrical or corresponding volume formed by the essentially elongated part of the handpiece (10) in the direction of the tip part (11) as shown in Fig. 4. Centering enhances ergonomics of the instrument and makes working more precise when the moment arm from the end of the tip to the central line of the handpiece is short. Therefore, no moments that would hamper the work are created or at least they are very small. The hand piece (10) may comprise a first and a second end and at both ends may be arranged a tip part (11) comprising a modelling part (12).

Parts of an instrument according to the invention do not necessarily need to be parts of constant diameter or cylindrical. Thus, when talking about "a central axis" or "an axis corresponding a central axis", what is meant in this application is an axis which goes through a three dimensional piece having a first end and a second end and, considering the shape of the piece in question, essentially at its center.

In the solution according to Fig. 1 the modelling part (12) is ar- ranged to protrude from the tip part (11) such that the angle between the central axis of the modelling part (12) and the central axis extending from said second end (112) of the tip part (11) towards the first end (111) is 90°, preferably between 60°-120°, such as any of the angles about 60°, about 90° or about 120°. Fig. 3 shows an in- strument in which protruding direction of the modelling part (12) from the tip part (11) is arranged at an angle other than orthogonal - or, in which central axis of the tip part (11) and central axis of the modelling part (12) are not at right angles with respect to each other.

The modelling part (12) can be arranged to be connected to the tip part (11) also such that the angle between the central axis of the modelling part (12) and the central axis of the tip part (11) , or of an axis comparable with that, is adjustable.

The modelling part (12), or any part joining to it, can be arranged to the tip part (11) as detachably connected, whereby various kinds of modelling parts (12) may be used in the instrument, such as modelling parts (12) or modelling heads (14) which produce directional patterns of the intensity distribution of a different shape and/or orienting in a different direction. The modelling part (12) and the modelling head (14) can be connected to each other by a connecting element (13) . Also, the modelling part (12) and the tip part (11) as well as the tip part (11) and the handpiece (10) can be connected together by a connecting element. The possible different angles between the various parts and/or the detachable connection may be realized by such a connection element. Connection between various parts of the instrument, such as connection of the modelling part (12) to the tip part (11) , for example, may be realized in other ways as well and be arranged to be adjust- able in other ways as well, such as turnable. The connection can also be realized by some other construction than the connection element. For example, a joint arrangement suitable for the purpose may be arranged between the parts, such as a joint arrangement comprising at least two joint positions which can be locked. The connections be- tween various parts of the instrument can be arranged fixed, adjustable, detachable, or to contain different of these means for connection between separate parts. For example, the tip part (11) and the modelling part (12) may be realized as a fixed construction and the tip part (11) arranged to the handpiece (10) as detachably connect- able.

According to one preferable embodiment of the invention a hollow or a light conducting modelling part (12) comprises a modelling head (14) of essentially the shape of a solid of revolution, i.e. is a piece whose cross section is essentially of the shape of a circle or an oval, or the modelling part (12) itself forms such a modelling head. The shape and size of the modelling head (14) is preferably arranged applicable for modelling filling material in a tooth cavity. The modelling part (12) and the modelling head (14) emits a directional pat- tern of the intensity distribution of light of a certain shape, and the modelling head (14) may be arranged to refract the direction of travel of light directed to it, such as at least essentially in one desired direction, such as at least essentially in the direction of the first end (111) of said tip part (11) . The shape, size and con- struction of the modelling head (14) may be arranged to direct light to at least one inner wall of a tooth cavity. According to one preferable embodiment of the invention the modelling part (12) is realized such that when it is connected to the tip part (11) , it pro- trudes from the tip part such and/or it is optically realized such that the angle between the central axis of the orientation of the directional pattern of the intensity distribution of the light emitted by the modelling part (12) and the central axis of the tip part (11) , or an axis comparable with that, or the central axis of the tip part (11), or an axis comparable with that, is between 30°-150°, preferably between 60°-120°, such as one of the angles about 60°, about 90° or about 120°.

Preferably, the greatest diameter of the modelling part (12) is arranged to be smaller than about 8 mm, and the diameter of the modelling head (14) possibly detachably connected to it to be between 1-6- mm, such as its diameter to become smaller towards the tip of the modelling head (14) . The greatest diameter of the modelling part (12) is preferably arranged in the area of its base and the modelling part (12) to become narrower towards its tip, i.e. in the direction in which the modelling part (12) protrudes from the tip part (11) towards a tooth when being at its operation position within patient's mouth.

At least two modelling parts of different shapes and/or producing directional patterns of intensity distribution directing to different orientations can be arranged to the tip part (11) as detachably connected. The means for generating light are preferably located at the essential proximity of said second end (12) of the tip part (11), preferably at the essential proximity of the modelling part (12) or at the modelling part (12) itself. Also the means for generating light can be arranged to comprise at least one light source component which is detachably connected. As partly already noted above, T^,Tm components emitting light in the wave length range of e.g. essentially white and essentially blue light can be arranged in the instrument, to be optionally used.

Means for generating light is arranged to the instrument preferably as detachably connected or it is arranged as a part of some detachably connected part. Then, a means for producing an identification signal according to what kind of a light source is connected to the instrument may be arranged in connection with the instrument, such as to the connection construction which enables the detachable connection in question, for example.

At least an essential portion of the electronics needed in said means for generating light may be arranged in the handpiece (10) of the instrument. A chargeable and/or a replaceable power means may be arranged to the handpiece (10) , or to a connection means needed for coupling the instrument to a dental care unit.

According to one preferable embodiment of the invention a small but powerful LED light source component or a LED group is arranged in connection with the modelling part (12) at an appropriate angle with respect to the central axis of the tip part (11) , or with respect to an axis comparable with it. Then, the instrument can be realized as light in construction and with high optical efficiency. Suitable LED components are Cree 4550 and Nishia NSCB455AT, for example, and e.g. Cree CPR3CR can be mentioned as a suitable LED chip. Different detachable connectable tip parts (11) may be arranged for the instrument.

Thus, according to the invention a dental instrument is brought about by which one can both plug filling material and cure it by radiation which is within an appropriate wave length range, and which makes er- gonomic working positions possible even with the more awkward sub- jects to be operated. In a situation in which dimensions of especially the components of the instrument which are taken into the patient' s mouth do not exceed the width of molars, seeing especially to the area of the rearmost teeth is easier. For example, the abovemen- tioned Cree LED is easy to fit within such a collar whose greatest outer diameter is about 7-8 mm and narrowing to about 5-6 mm when going towards a tooth. Nishia LED is even smaller than Cree. A changeable modelling head is preferably a solid of revolution and preferably made e.g. of plastic suitable for this use.

Above, the invention has been described with the help of some of its preferable embodiments, but naturally it can be realized by other ways as presented as well within the inventive idea defined by the attached claims. The cross sections of the parts of the instrument may be e.g. essentially of the shape of a circle, of an oval, of a square or of a rectangle and at least some or even all parts of the instrument may be arranged detachably connected. However, preferably at least one of the instrument parts is arranged detachable connected in such a way that another modelling part and/or modelling head may be changed to the handpiece.

Further, as mentioned above already, the purpose of the attached figures is not to absolutely or generally show dimensions of the instru- ment, or mutual relations of dimensions of parts of the instrument according to the invention. The length of the head part, for example - or, when the modelling part is arranged as an extension at the second end of the head part the dimension from the connection point of the first end of the head part and the handpiece to the furthest edge of the modelling part may be arranged in one preferable embodiment of the invention to be relatively longer than that presented in the attached figures. Especially, when a light switch designed to be used while operating is arranged at the handpiece of the instrument, in one preferable embodiment of the invention said length of the head part, or the dimension in question, is at least about 50 mm, preferably at least 55 mm. In such an instance, operating on the rearmost teeth as well is possible without the dentist needing to take his fingers into the patient's mouth or in the region of the lips for using the light switch.

Claims

1. A dental instrument, coπprising a handpiece (10) and at least one tip part (11) joining thereto and consisting of at least one piece which comprises a first end (111) and a second end (112) , which first end of the tip part (111) is fixedly or detachably attached to the handpiece (10), characterized in that said tip part (11) is arranged to consist of a construction which comprises a modelling part (12) fixedly or detachably attached to the tip of the second end (112) of the tip part or in the essential proximity of said tip and protruding from the tip part (11), the modelling part (12) being arranged for modelling tooth filling material and to be translucent or to comprise a translucent component and, arranged at the tip part (11) or the modelling part (12) joining to it a means for generating light (15) used at least for curing tooth filling material, and wherein dimensions and forms of said tip part (11) , at least at the essential proximity of the second end (112) of the tip part (11) , or dimensions and forms of said second end (112) of the tip part (11) itself are arranged such that when the instrument is observed at its position in the patient's mouth regarding operating on one of the premolars or molars, i.e. from an angle with respect to a central axis of said tip part (11) , or, from the direction the person performing the operation sees the instrument at such an instant, said second end (112) of the tip part (11) or said part of the tip part (11) locating at the essential proximity of the tip part (11) only partially blocks a view to the premolar or molar in question.

2. The dental instrument according to claim 1, characterized in that essentially in the region of the second end (112) of the tip part (11) at least, a horizontal dimension of the cross section of the tip part is arranged smaller than a vertical dimension of this cross section.

3. The dental instrument according to claim 1 or 2, character- ized in that of the dimensions of said tip part (11), at least the horizontal dimension of its cross section at least essentially at said second end (112) of it is arranged smaller than the largest di-

RECTMED SHEET (Rule91) mension of the cross section of the modelling part (12) arranged at the second end (112) of said tip part (11) .

4. The dental instrument according to any of the claims 1-3, char- acterized in that essentially at the second end (112) of the tip part dimensions of the cross section of said tip part (11) , at least a horizontal dimension of a cross section of the tip part (11) , is smaller than the corresponding dimension essentially at the first end (111) of the tip part (11) .

5. The dental instrument according to any of the claims 1-4, characterized in that the tip part (11) is such designed that when one moves from the second end (112) of the tip part towards its first end (111) , always all dimensions of the cross sections of the tip part are as large or larger than the dimensions of the corresponding previous cross section, i.e. the tip part (11) is arranged to thicken smoothly towards its first end (111) .

6. The dental instrument according to any of the claims 1-5, char- acterized in that said tip part (11) and modelling part (12) are arranged to join each other such that the second end (112) of the tip part (11) is attached to the modelling part (12) essentially from the side of the modelling part (12) .

7. The dental instrument according to any of the claims 1-6, characterized in that at the point in which the tip part joins to the modelling part (12) at least a horizontal dimension of a cross section of the second end (112) of said tip part is smaller than dimensions of the cross section of the modelling part (12) at this junction.

8. The dental instrument according to any of the claims 1-7 , characterized in that said modelling part (12) is arranged to protrude from said tip part such that an angle between the central axis of the modelling part (12) , or an axis comparable with that, and the central axis of the handpiece (10) joining to the tip part (11) , or an axis coitparable with that, or the central axis of the tip part (11) , or an axis comparable with that,

is between 30°-150°, preferably between 60°-120°, such as one of the angles about 60°, about 90° or about 120°.

9. The dental instrument according to any of the claims 1-8, characterized in that said modelling part (12) is arranged as for its dimensions and forms such that when one observes it at its operating position in a patient' s mouth regarding operating on one of the premolars or molars, i.e. from the direction the person performing the operation sees the instrument at such an instant, said modelling part (12) only partially blocks a view to the premolar or molar in question.

10. The dental instrument according to any of the claims 1-9, characterized in that said modelling part (12) is arranged as for its size such that, concerning cross sections of the modelling part (12) essentially with respect to its central axis, the greatest diameter of any cross section of the modelling part (12) , or the length of the longest side of the cross section, is about 11 mm for the most, such as about 8 mm for the most, preferably about 7 mm for the most.

11. The dental instrument according to any of the claims 1-10, characterized in that on a plane which is essentially at right angles to a plane comprising the protruding direction or the central axis of the modelling part (12), the width and the diameter of the longitudinal section of the tip part (11) is arranged smaller than 5 mm, at least at said second end (112) of the tip part (11) .

12. The dental instrument according to any of the claims 1-11, characterized in that said modelling part (12) is arranged to protrude from said tip part (11) such, and/or it is realized optically such that the angle between the central axis of orientation of the directional pattern of the intensity distribution of the light emitted by the modelling part (12) and the central axis of the hand- piece (10) joined to the tip part (11) , or an axis comparable with that, or the central axis of the tip part (11) , or an axis comparable with that, is between 30°-150°, preferably between 60°-120°, such as one of the angles about 60°, about 90° or about 120°.

13. The dental instrument according to any of the claims 1-12, characterized in that said modelling part (12) comprises a light conducting, a light refracting and/or a hollow modelling head (14), or the modelling part (12) itself makes up such a modelling head.

14. The dental instrument according to any of the claims 1-13, characterized in that the shape and size of the tip of the modelling part (12) , or that of the modelling head (14) arranged at the tip of the modelling part is arranged applicable for plugging filling material in a tooth cavity.

15. The dental instrument according to any of the claims 1-14, characterized in that the modelling part (13), or the model- ling head (14) arranged at the tip of the modelling part (12) is arranged to change direction of travel of light, such as essentially in at least one desired direction, such as at least essentially in the direction of the first end (111) of said tip part (11) and/or at least on one inner surface of a tooth cavity.

16. The dental instrument according to any of the claims 1-15, characterized in that position of the modelling part (12) and/or that of the modelling head (14) arranged joining to the modelling part (12) is arranged adjustable.

17. The dental instrument according to any of the claims 1-16, characterized in that arranged between the tip part (11) and the modelling part (12) , and/or between the modelling part (12) and the modelling head (14) arranged at the modelling part (12) there is a joint, such as a joint arrangement comprising two joint positions that may be locked, to enable changing of the mutual position of said parts.

18. The dental instrument according to any of the claims 1-17, characterized in that said modelling part (12) comprises a modelling head (14) the shape of the cross section of which is essentially a circle or an oval, or the modelling part (12) itself forms such a modelling head.

19. The dental instrument according to any of the claims 1-18, characterized in that a detachably connected modelling head (14) is arranged at the modelling part (12) for enabling attaching to the instrument a modelling part (12) or a modelling head (14) which creates at least two directional patterns of intensity distribution of different shapes and/or orienting in different directions.

20. The dental instrument according to any of the claims 1-19, characterized in that the greatest diameter of said modelling part (12) and/or of the modelling head (14) arranged attached thereto is less than about 8 mm and the smallest diameter between about 1-6 mm as observed essentially in relation to the central axis of the modelling part (12) or the modelling head (14) , as like such that the greatest diameter is arranged essentially at the base of the modelling part (12) and the diameter of the modelling part (12) and/or of the modelling head (14) is arranged to become smaller in the direction of its head.

21. The dental instrument according to any of the claims 1-20, characterized in that dimensions of a cross section of said tip part (11) , at least at said second end of it, is arranged smaller than the corresponding dimensions of a cross section of the handpiece (10) joining to the first end (111) of the tip part (11) .

22. The dental instrument according to any of the claims 1-21, characterized in that the dimension from the first end (111) of the tip part (11) to the second end (112) of the tip part, or a dimension from the first end (111) of the tip part (11) to the fur- thest point of the modelling part (12) arranged in connection with essentially the second end (112) of the tip part (11) is no less than 50 mm, such as no less than 55 mm.

23. The dental instrument according to any of the claims 1-22 , characterized in that a switch (16) for using said means for generating light (15) is arranged to the instrument, such as to the handpiece (10) of the instrument.

24. The dental instrument according to any of the claims 1-23, characterized in that said means for generating light (15) is placed in the essential proximity of said second end (112) of the tip part (11) , such as essentially in the essential proximity of said modelling part (12) or to the modelling part (12) itself.

25. The dental instrument according to any of the claims 1-24, characterized in that said means for generating light (15) comprises one or more, such as one or two T.Kn components, out of which at least one is a LED which emits essentially wave length of blue light or other wave length which cures tooth filling material, such as T.Kn components which emit light essentially in the wave length range of white and blue light, whereby in case there are at least two different such components, they are arranged to be option- ally used.

26. The dental instrument according to any of the claims 1-25, characterized in that said means for generating light (15) is arranged detachably connected to the instrument or it is arranged to be a part of one part being arranged detachably connected, and that the connection construction which enables said detachable connection comprises means for generating an identification signal based on the type of the light source connected to the instrument.

27. The dental instrument according to any of the claims 1-26, characterized in that said handpiece (10) is arranged to consist or comprise an essentially elongated part, and said tip part (11) is arranged to orientate essentially parallel with said elongated handpiece (10) .

28. The dental instrument according to any of the claims 1-27, characterized in that said modelling part (12), the head of^* the modelling part (12) and/or the modelling head (14) of the model- ling part (12) is centered to locate within an extension of a cylindrical or corresponding volume formed by an essentially elongated part of the handpiece (10) in the direction of the tip part (11) .

29. A dental instrument according to any of the claims 1-28, characterized in that the central axis of said tip part (11) is arranged at an angle with respect to the central axis of the handpiece (10) .

30. A dental instrument according to any of the claims 1-29, characterized in that the handpiece (10) is essentially elongated and comprises a first and a second end and at both of these ends is arranged as fixed or detachably a tip part (11) comprising a modelling part (12) .