DE4030734A1 - Dental treatment by pulsed solid state laser - using fibre-optics tool and hydroxy-apatite or tetra:calcium phosphate filler - Google Patents

Abstract

A process and appts. are claimed for non-mechanical, non-contact treatment of various teeth, for prodn. of permanent and non-toxic inlays in treated tooth cavities, and for non-mechanical prepn. and filling of root canals using a pulsed laser system, a fibre-optics transmission system, a hand piece with replaceable heads and a hydroxy-apatite or tetracalcium phosphate filler. The novelty is that (i) the laser system is a pulsed solid state laser with a crystal of Cr:Al2BeO4 (alexandrite), doped YAG, doped YSGG or doped YLF and operated at 10mJ-2J pulse energy, 100 nsec - 1msec. pulse duration and 1-50 Hz repetition rate; (ii) the optical transmission system comprises a single glass fibre of 50-800 microns core diameter; (iii) the hand piece and replaceable head unit has a fibre-optics transmission, system, a spherical or gradient lens, a beam deflection element, an optical quartz glass window and a mechanical feed line for an aq. aerosol; (iv) the tooth cavity or root canal filling is a powder, granulate, suspension or paste contg. hydroxyapatite or tetracalcium phosphate of 0.02-10 microns particle size and 1-10% (based on the hydroxyapatite or tetracalcium phosphate) of a tetracycline deriv.; and (v) crystallisation of the tooth cavity or root canal filling is carried out using the laser handpiece. ADVANTAGE - Dental treatments are carried out with a high degree of patient comfort and with absolute and permanent closure of root canal and tooth cavities.

Description

Background of the Invention

The invention relates to methods and devices for non-mechanical, non-contact treatment of carious Tooth defects, the creation of permanent and non-toxic Inlays in these tooth cavities treated in this way, as well as the non-mechanical preparation and filling of sausage individual channels using pulsed laser radiation.

Use in restorative and preventive dentistry The methods and devices used are exclusively mechanical door, d. H. the carious tooth defects in the enamel or dentin with high-speed drills or ultrasonic files removed in the contact procedure. Depending on the number of revolutions of the me metallic drill bits are special tooth or Bone resonances stimulated, so that the well-being of the Pati ducks is very badly affected during treatment. In the root canal treatment mechanical In instruments such as K-drills, K-files, Hedstroem files or Ultra sound files used. In the case of manual preparation of the A so-called root canal is covered with mechanical files "Smear Layer ′ the surface of the canal wall, the fine dentin canals are clogged with dentin mud. The goal of an inert hermetically sealing substance instead of the extirpated Introduce pulp in order to reinfect the canal later prevent hematogenous or coronal pathway, he will not enough.

The most used root canal filling material today Gutta-percha, a product of different compositions.

It contains an average of 19-22% gutta-percha as a matrix, 59-75% Zinc oxide as filler, 1.5-17% metal sulfide as X-ray con trap agent and 1-4% waxes or synthetic resins to increase the Plasticity. Gutta-percha is practically considered an inert material, however, there are also animal studies that do  have shown to be toxic. Processing guttaper cha in the root canal is done by softening the material dir ect by heat or indirectly by mechanical friction. The This thermoplastic root filling method requires a lot of manual work les skill because of the degree of filling of the plastic material is difficult to control.

In addition to Amal gam - an alloy of mercury and other metals that demonstrably shows toxicity - pastes with ceramic filling Shares and composite inlays that are made using UV light be hardened. These materials tend to shrink due to their shrinkage behave during the formation of gaps, so that a bak re-infection of the enamel or dentin is lightened. A long-term, hermetic seal the tooth cavity is not reached.

From the patent US-48 18 230 is a method for Besei tooth decay and to remove diseased soft tissue known with a YAG laser.

Furthermore, from the patent US-47 84 135 is a method and a device for removing organic biological Ma material without heat development in neighboring areas he known ultraviolet wavelength smaller than 200 nm. Furthermore, a fine filling process is known from OS-DE 38 16 237 and a filler for dental purposes from a powder, a granulate, a suspension or one Paste containing hydroxyapatite has become known.

The invention is therefore based on the object, new procedure Ren and improved devices for non-mechanical loading treatment of tooth defects, as well as the non-mechanical repair ride and fill root canals and tooth cavities using to provide pulsed laser radiation, both a he represent considerable comfort for the patient, as well as one absolute and permanent closure of root canal and tooth enable cavities.

Summary of the invention

Novel devices and methods are in accordance with the invention proposed to use a pulsed laser system, a fiber  optical transmission system, a dental fiber optic Laser handpiece with interchangeable therapy headpieces and a a special filling material based on hydroxyapatite or tetracalcium phosphate both non-mechanical treatments of carious tooth defects as well as their filling, as well as a Root canal preparation and filling nen.

According to the invention, a pulsed, compact Cr: Al ₂ BeO ₄ (alexandrite) solid-state laser is advantageously used as the radiation source for all dental processes, and can be used to provide tunable wavelengths in the range of 720-860 nm. By adding a suitable optical module, wavelengths of 360-430 nm can be achieved in the so-called frequency-doubled range. According to the invention, this wavelength range is advantageous in several respects. Firstly, the threshold energy densities for ablation (photodisruption and photodecompensation) in this area are significantly lower than in the visible wavelength range, ie the total radiation dose for the patient that is necessary for laser treatment is minimized by using these wavelengths. Furthermore, there is no damage to the DNA in the wavelength range from 360-430 nm, since the proteins and the DNA have their absorption maxima in the range of 200 nm. In the case of the excimer laser at a wavelength of 193 nm and with too high a radiation dose, this can lead to carcinogenic reactions in healthy hard or soft tissue. Finally, the wavelength range of 360-430 nm is in the main absorption range of tetracycline - an antibiotic - which is admixed according to the invention in a suitable concentration with hydroxyapatite or tetracalcium phosphate.

A pulsed, repetitively Q-switched Tm: YSGG (Thuli um-doped yttrium scandium gallium) solid-state laser with a tunable wavelength range of 1.85-2.16 µm can be used advantageously for this process. Fre This laser system delivers double the number with an optical one Additional module tunable wavelengths in the range of 0.925-1.08 µm.

Hydroxyapatite is both part of the mineral substance of Bone as well as the tooth hard (enamel) or Tooth-soft (dentine)  -Substance. The enamel consists of 96% inorganic Kal calcium salts in a matrix structure (hydroxyapatite). The tooth dentin is also made up of a hydroxyapatite structure, but contains about 35% organic material, so it is le tissue. A corresponding temperature increase of 10-15 ° C with respect to the normal temperature of 37 ° C can already Necrosis or tissue death, such as this by using an Nd: YAG (Neodymium-doped Yttri to aluminum garnet) permanent laser. In contrast, the pulse length of the laser radiation - as in the case of the pulsed alexandrite laser - in the order of magnitude thermal relaxation time of the tissue material chosen, it is possible to dose the temperature increase of the tissue locally ren that certain chemical and physical changes be initiated while taking in the surrounding tissue area remains below the threshold of an irreversible change. The same applies to the choice of the wavelength of the laser. Tetracycline has a number of derivatives (chlorotetracycline, Demelocycline, oxytetracycline, rolitetracycline), which are preferred bind to lime compounds. For example, trade Usual doxycycline an absorption maximum for laser radiation at 372 nm, the other tetracyclines are close to this measure ximum. The tetracyclines also block protein synthesis of microorganisms and are therefore orally bacteriostatic effective against pathogens.

A powder, a granulate, a suspension or a Pa ste, the hydroxylapatite or tetracalcium phosphate in one Contains grain size of about 0.02-10 µm, is according to the set wavelength of the laser a tetracycline derivative in a concentration of about 1-10% based on Hxdroxylapatit or tetracalcium phosphate added. In addition, can another excipient, e.g. B. a promoting the calcification Protein, to be added. This mixture is used as a filler used for the tooth cavity and the tooth roots and with Las radiation crystallized.

Description of the drawings

Fig. 1 Dental laser handpiece for the treatment of carious tooth defects.

Fig. 2 Dental laser handpiece for the preparation of Wurzelka channels.

Fig. 3 modified embodiment of a dental laser handpiece for the preparation of root canals.

Fig. 4-6 process steps for laser treatment of carious tooth defects and generation of tooth cavity fillings by means of a dental laser handpiece.

Fig. 7-10 process steps for root canal preparation and root canal filling using a dental laser handpiece.

Detailed description of the invention

The dental laser systems available today are exclusive Lich monotherapy devices, d. H. you can only do one exactly defined wavelength in the ultraviolet (excimer laser), in Visible (frequency doubled Nd: YAG laser) or in the infra red (Nd: YAG laser). These systems can either only ablate (UV range) or only coagulate (Visible and IR range), so that ent with a laser system neither only surgical nor only reparative dentistry can be carried out.

The multi-therapy methods according to the invention are as follows described in detail.

A dental laser handpiece for the treatment of carious tooth defects is shown schematically in FIG. 1. The laser hand piece 1 has on its front part an easily exchangeable therapy head piece 1 a, so that a single basic hand piece is sufficient for several dental procedures such as tooth cavitation and root canal preparation. The pulsed laser radiation is guided over a fiber optic light waveguide 2 from the laser source to the handpiece 1 . The laser is fixed as a ceiling or table device, the fiber optic system 2 is flexible and allows the surgeon with the handpiece 1 complete freedom of movement within the patient's oral cavity. The fiber optic cal waveguide 2 is preferably an optical fiber with a quartz core and doped quartz jacket with a core diameter of 200-600 microns. When using an IR solid-state laser as the radiation source, the light guide core is preferably made of anhydrous quartz glass material in order to minimize power loss of the laser radiation from the source to the treatment site. The emerging from the optical fiber 2 divergent laser beam 3 is parallelized by an optical element 4 , preferably a spherical lens made of quartz glass, sapphire or anhydrous quartz glass. The optical fiber 2 is located at the rear focal point of the optical element 4 . The par allele laser beam 3 , which runs freely in the handpiece, is focused by a further optical element 5 , preferably a long focal length lens, after it has been deflected by a mirror 6 in its beam direction so that the focused beam 10 in an optimal manner can be directed to the carious tooth defect. The front part 1 a is connected to the main hand piece 1 separably. Two optical elements 7 and 7 a, preferably anti-reflective quartz glass windows, prevent the ingress of dust and dirt into the separate items. These optical windows are easy to clean if necessary. In addition, an air / water mixture ("spray") is brought up by the handpiece 1 via standard feed lines 8 and 8 a of dental accessories, which is directed through openings 9 and 9 a to the tooth defect for the purpose of cooling.

Fig. 2 shows schematically an inventive dental laser handpiece for the preparation of root canals. 1, the handpiece 11 has as the handpiece 1 of FIG. An easy exchange bares therapy head piece 11 a, a fiber-optic lightwave conductor 12, spherical lenses 14 and 14 a, a deflecting mirror 15 and antireflection quartz glass window 16 and 16 a. The parallel laser beam 13 is in this case via a further ball lens 14 a on a fiber optic optical waveguide piece 17 , preferably an optical fiber with quartz glass core and doped quartz glass cladding with a core diameter of 200-600 microns, focused. The proximal optical fiber end is located in the front focal point of the ball lens 14 a. The optical fiber piece 17 is easily replaceable via the separable handpiece front part 11 a like conventional dental metal drill bits. The La serhandstück 11 also has standard leads 19 and 19 a, which supply the tooth root canal for cooling an air / water mixture through the openings 20 and 20 a. The laser beam 18 emerges divergently at the distal end of the optical fiber piece 17 .

Fig. 3 shows schematically a modified embodiment of a dental laser of the present invention there handpiece for the treatment of root canals. The handpiece 21 has as the handpiece 11 of Fig. 2, a simple replaceable therapy head piece 21 a, a fiber-optic optical waveguide 22, spherical lenses 24 and 24 and antireflection a quartz glass window 26 and 26 a. The parallel laser beam 23 is focused as in FIG. 2 via a spherical lens 24 a on a fiber optic optical waveguide piece 27 . The proximal end of the light guide is located at the front focal point of the spherical lens 24 a. The optical Fa water 27 is easily replaceable via the separable handpiece front part 21 a. The front part 21 a is slightly angled according to the anatomy of the tooth root canal, so that the surgeon can insert the light guide piece 27 into the root canal of the patient with good visibility. The laser handpiece 21 also has standard feed lines 29 and 29 a, which supply an air / water mixture to the tooth root canal for cooling via the openings 30 and 30 a. The laser beam 28 emerges divergently at the distal end of the optical fiber piece 27 .

Figs. 4-6 show schematically the individual Verfahrensschrit te for laser treatment of carious tooth defects, and for the generation of He Zahnkavitätsfüllungen means of the dental handpiece 1 laser.

A carious tooth defect 31 , which is either only located in the tooth enamel 32 or can also reach into the tooth dentin 33 , is caused by the pulsed laser radiation 10 from an Alexan third laser source, a Tm: YAG (thulium-doped yttrium aluminum garnet) -, a Tm: YSGG (thulium-doped yttrium scan dium gallium garnet) -, a Tm: Ho: YAG (thulium, holmium-doped yttrium aluminum garnet) -, a Tm: Ho: Cr: YAG (thulium, holmium, chromium- doped yttrium aluminum garnet) -, a Tm: Cr: YAG (thulium, chromium-doped yttrium aluminum garnet) -, a Tm: Er: YAG (thulium, erbium-doped yttrium aluminum garnet) -, a Tm: Er: Cr: YAG (thulium, erbium, chromium-doped yttrium aluminum garnet) - or an Nd: Er: Cr: YAG (neodymium, erbium, chromium-doped gadolinium scandium gallium garnet) - laser source of suitable wavelength and pulse duration with handpiece 1 and the Therapy head piece 1 a ablated ( Fig. 4). The wavelength, but especially the pulse duration of the laser system, is chosen so that the living tissue of the root canal 34 is not irreversibly damaged by axial heat conduction and dies. This is also prevented by the air / water mixture which coaxially emerges from the laser handpiece 1 to the focused laser beam 10 .

Fig. 5 shows diagrammatically the result of the Kariesablation after laser treatment with a resulting tooth cavity 35 in tooth enamel or dentin 32 33rd This tooth cavity is made with a powder, a granulate, a suspension or a paste 36 , which contains hydroxyapatite or tetracalcium phosphate in a grain size of about 0.02-10 µm and which contains a tetracycline derivative in a concentration of 1-10% based on hydroxyl apatite or tetracalcium phosphate has been added, gradually filled up and irradiated with pulsed laser radiation 10 via the laser handpiece 1 until it crystallizes ( FIG. 6). The laser handpiece 1 is placed by the surgeon so that its focal point is above the tooth surface, so that the laser radiation 10 divergent, ie te with a lower pulse energy density, hits the filling 36 .

FIGS. 7-10 schematically show the individual Verfahrensschrit te for root canal preparation and obturation means of the dental laser hand piece 11. With the treatment head 1 a shows a tooth cavity is in accordance. 4 35 through the enamel and the dentin 32 is exposed 33 to the inputs of the tooth roots 34th After the simple exchange of the therapy head 1 a against the therapy head 11 a, the optical fiber guide 17 is advanced antegrade into a root canal with laser emission and the pulp extirpated by ablation ( FIG. 7). The laser ablation with the therapy head 11 a completely removes the necrotic tissue from the endodontic cavity. Additional rinsing of the endodontic canal with an air / water spray from the laser handpiece 11 during the root canal preparation optimally removes possible dentin mud, since with a suitable choice of the laser pulse length, laser-induced shock waves are also generated in the rinsing liquid, which cause a complete disinfection of the root canal due to cavitation effects . The fine dentin tubules in tooth dentin 33 are thus clean and open, and can then be hermetically sealed. For apical limitation of the root canal filling at the physiological foramen, ie at the tin / cement boundary ( Fig. 8), a suitable gutta-percha pin 37 or a pin containing hydroxylapatite or tetracalcium phosphate mixed with a suitable concentration of tetracycline is placed in the Root canal inserted and melted with the therapy head piece 11 a over the optical fiber 17 , so that a gap-free sealing of the canal and the tinker tubules takes place on the physiological foramen. The rest of the root canal cavity 34 is then successively treated with a powder, a granulate, a suspension or a paste 36 which contains hydroxylapatite or tetracalcium phosphate in a grain size of about 0.02-10 µm and which contains a tetracycline derivative in a concentration of 1-10%. based on hydroxylapatite or tetracalcium phosphate has been added, filled up and irradiated with pulsed laser radiation from the optical fiber 17 via the laser handpiece 11 until it crystallizes out and the root canal is hermetically sealed ( FIG. 9). The remaining tooth cavity 35 is then filled according to the method of FIG. 6 with the filling 36 and crystallized with the laser handpiece 11 and the Thera piekopfstück 1 a until the tooth surface is metically sealed ( Fig. 10).

Claims (1)

Methods and devices for the non-mechanical, non-contact treatment of carious tooth defects, for the production of permanent and non-toxic tooth deposits (inlays) in these tooth cavities treated in this way, as well as for the non-mechanical preparation and filling of root canals by means of a pulsed laser system, a fiber optic transmission system, and a dental laser handpiece with exchangeable therapy heads and a special filling material based on hydroxyapatite or tetracalcium phosphate, characterized by the following features:

• 1) The laser system is a pulsed solid-state laser with a laser crystal made of Cr: Al ₂ BeO ₄ (alexandrite) with a fundamental wavelength range in the visible spectral range from 720-860 nm and a frequency-doubled wavelength range in the ultraviolet spectral range from 360-430 nm,
• 2) the laser system is a pulsed solid-state laser with a laser crystal made of Tm: YAG, Ho: YAG, Tm: YSGG, Ho: YSGG, Tm: Ho: YAG, Tm: Ho: Cr: YAG, Tm: Er: Cr : YAG, Tm: Cr: YAG, Tm: Er: YAG, Tm: Ho: Er: YLF or Nd: Er: Cr: YAG with different doping of the laser-active atoms of the laser crystal and a fundamental wavelength range from 1.85-2.16 µm,
• 3) the pulse energies of the solid-state laser systems are 10 mJ to 2 J, the pulse durations 100 nsec to 1 msec,
• 4) the repetition rates of the solid-state laser systems are 1 to 50 Hz,
• 5) the optical transmission system from the laser source to the laser handpiece consists of an optical single glass fiber with a core diameter of 50 to 800 µm,
• 6) the single glass fiber is made of optical quartz glass material with different OH⁻ components,
• 7) the dental laser handpiece consists of a basic handpiece and interchangeable therapy headpieces, which are separably connected to one another,
• 8) the therapy head pieces are optically separated from the basic hand piece by anti-reflective quartz glass windows,
• 9) the basic handpiece contains the fiber optic transmission system, a spherical or gradient lens, a beam deflection element, an optical quartz glass window and mechanical supply lines for a water-containing aerosol,
• 10) the therapy head pieces include an optical quartz glass window, a spherical, gradient or spherical lens, mechanical feed lines for a water-containing aerosol and a fiber optic optical waveguide piece made of optical quartz glass material with different OH unterschiedlichen components,
• 11) a powder, a granulate, a suspension or a paste which contains hydroxyapatite or tetracalcium phosphate in a particle size of 0.02 to 10 μm is used to fill the tooth cavities,
• 12) the hydroxylapatite or the tetracalcium phosphate is admixed with a tetracycline in a concentration of 1 to 10% based on hydroxylapatite or tetracalcium phosphate,
• 13) the tetracycline derivative is doxycycline, chlorotetracycline, demeloxycycline, oxytetracycline or rolitetracycline,
• 14) the root canal preparation is carried out in a contact process with a single glass fiber made of optical quartz glass material with different OH proportions and a core diameter of 50 to 400 µm,
• 15) the endodontic canal is rinsed during the laser treatment with water-containing aerosols,
• 16) root canal preparation is supported by laser-induced shock waves,
• 17) the apical limitation of the root canal filling on the physiological foramen is made using a gutta-percha stick or a stick containing hydroxylapatite or tetracalcium phosphate,
• 18) the stick made of hydroxylapatite or tetracalcium phosphate is mixed with a tetracycline in a concentration of 1 to 10% based on hydroxylapatite or tetracalcium phosphate,
• 19) for filling the root canal cavity, a powder, a granulate, a suspension or a paste which contains hydroxylapatite or tetracalcium phosphate in a grain size of 0.02 to 10 µm and which contains a tetracycline derivative in a concentration of 1 to 10% based on hydroxylapatite or Tetracalcium phosphate is used, used
• 20) The crystallization of the filling of the tooth cavity and the filling of the root canal takes place without contact via the dental laser handpiece.