WO2008072033A1 - Appareil chirurgical et procédé de traitement de tissus osseux biologiques, en particulier pour la chirurgie dentaire, basés sur un laser à fibre - Google Patents

Appareil chirurgical et procédé de traitement de tissus osseux biologiques, en particulier pour la chirurgie dentaire, basés sur un laser à fibre Download PDF

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Publication number
WO2008072033A1
WO2008072033A1 PCT/IB2006/054738 IB2006054738W WO2008072033A1 WO 2008072033 A1 WO2008072033 A1 WO 2008072033A1 IB 2006054738 W IB2006054738 W IB 2006054738W WO 2008072033 A1 WO2008072033 A1 WO 2008072033A1
Authority
WO
WIPO (PCT)
Prior art keywords
surgical apparatus
light radiation
tissue
water
fibre laser
Prior art date
Application number
PCT/IB2006/054738
Other languages
English (en)
Inventor
Stefano Bonora
Paolo Villoresi
Original Assignee
Consiglio Nazionale Delle Ricerche- Infm Istituto Nazionale Per La Fisica Della Materia
Universita' Degli Studi Di Padova
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Consiglio Nazionale Delle Ricerche- Infm Istituto Nazionale Per La Fisica Della Materia, Universita' Degli Studi Di Padova filed Critical Consiglio Nazionale Delle Ricerche- Infm Istituto Nazionale Per La Fisica Della Materia
Priority to PCT/IB2006/054738 priority Critical patent/WO2008072033A1/fr
Publication of WO2008072033A1 publication Critical patent/WO2008072033A1/fr

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C1/00—Dental machines for boring or cutting ; General features of dental machines or apparatus, e.g. hand-piece design
    • A61C1/0046—Dental lasers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/0006—Working by laser beam, e.g. welding, cutting or boring taking account of the properties of the material involved
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/14—Working by laser beam, e.g. welding, cutting or boring using a fluid stream, e.g. a jet of gas, in conjunction with the laser beam; Nozzles therefor
    • B23K26/146—Working by laser beam, e.g. welding, cutting or boring using a fluid stream, e.g. a jet of gas, in conjunction with the laser beam; Nozzles therefor the fluid stream containing a liquid
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K2103/00—Materials to be soldered, welded or cut
    • B23K2103/30—Organic material

Definitions

  • the present invention regards the treatment of biological hard tissues, and in particular of sound dentin and enamel for restorative dentistry.
  • the invention relates to a surgical laser apparatus and a method for ablating biological hard tissues.
  • the "hard” tissues of the tooth such as enamel and dentin.
  • the ablation of parts of the "hard” tissues of the tooth in order to shape the cavities to better host the restorative materials.
  • the enamel is the strongest tissue in the human body and so mechanic diamond burr is needed for its removal.
  • optical systems make it possible to carry the laser light to the treatment spot, by guiding its radiation in an optical fibre, and to focus the laser beam on a very small area of the target tissue, compatible with the dimensional ranges involved in the procedure, and therefore act with greater precision on the surface to be treated.
  • the techniques so far developed to apply laser radiation to hard tissues, and hard tissues of teeth in particular depend on the optical characteristics of the tissues (coefficient of absorption and diffusion as a function of wavelength) and their physical characteristics (heat conductivity, distribution of the nervous system) , as well as on the type of operation to be performed (cutting, removal of carious tissue, modelling of the tooth to apply implants or prostheses, et cetera) .
  • US 5,020,995 discloses a CO 2 laser operating at a wavelength of 10.6 ⁇ m, which was applied to the treatment of both soft and hard tissues of teeth. Its main drawback is due - on the one hand - to the increase in the local temperature of the tissue in case of irradiation with high-energy, short- duration pulses, and - on the other hand - to the heat propagation that occurs if the energy is reduced and the application time is increased.
  • Hard tissues require actions mostly of the ablative type, both to eliminate carious tissues and to remodel the shape of the tooth with the prospect of applying prostheses.
  • Some aspects of the propagation of light and heat inside the tooth are in fact very complex. This is linked to the structural anisotropy of the tooth, which is formed to a large extent by radially orientated hydroxyapatite crystals.
  • the presence of nerve endings, blood vessels, fibroblasts and odontoblasts in the pulp chamber makes the tooth sensitive to the overheating produced during the procedure.
  • irradiation with high-power pulses required in order to induce tissue ablation, must be limited in time, so as to allow the action of cooling systems that keep the pulp chamber at a tolerable temperature.
  • Excimer and neodymium in YAG (Nd: YAG) lasers were used in this context together with CO 2 lasers, initially. Considerable progress was achieved later by introducing lasers of the erbium in YAG or YSGG type (Er: YAG, Er: YSGG) operating at 2.94 ⁇ m and 2.79 ⁇ m, respectively.
  • Er: YAG lasers to eliminate dental caries has a widespread diffusion, as they are painless and accurate, and exploits the strong absorption peak of both hydroxyapatite and water, which are the main components of the tooth tissue.
  • US2006127861 discloses a semiconductor diode laser for hard tissues treatment. This patent exploits the advent of advanced optical systems able to couple high power diode laser bars radiation in optical fibres and the use of dyes to increase the local absorption of the hard tissues.
  • the advantages of semiconductor diode laser based systems is the simplified structure, easier handling, affordable costs, low maintenance with respect to a CO 2 laser or to a laser of the Nd: YAG or Er: YAG type.
  • the aim of the present invention is to provide a surgical laser apparatus for the treatment of hard tissues, such as for example the surfaces of teeth or bones, which is both reliable and highly efficient, and at the same time easy to handle and compact with respect to the known solutions.
  • Another object of the invention is to limit the high costs entailed by the prior art technologies.
  • Still another object is to provide a reliable and highly efficient method for the treatment of hard tissues, such as for example the surfaces of teeth or bones.
  • Figure 1 is an overall schematic view of a first embodiment of the surgical apparatus according to the invention
  • Figure 2 is an overall schematic view of a second embodiment of the surgical apparatus according to the invention.
  • Figure 3 is a diagram representing the absorption spectrum of water in a wavelength range of interest in surgical laser applications.
  • the apparatus comprises an optical fibre waveguide structure 12 including an active region 14 in a fibre section acting as a source of a coherent light radiation at a predetermined wavelength.
  • the active region 14 is a fibre section doped with a rare-earth metal element and delimited by semi- reflective mirrors 16 defining a fibre oscillating structure so as to bring about stimulated emission of coherent light at optical wavelengths comprised in the range between 1400nm and 2400nm as a result of radiative recombination of the charge carriers confined therein.
  • An excitation semiconductor pumping laser 18 is associated with the active region 14 and arranged to alter the thermodynamic equilibrium of the carrier populations therein in order to bring about a condition of population inversion.
  • a length of fibre 20 extends beyond the active region 14 for guiding the light radiation to the surface of the tissue to be treated, and delivering it through a contact tip 22, e.g. conical in shape. At least a portion of said optical fibre is flexible, and the overall dimension of the apparatus resembles that of a common ball pen.
  • the light radiation is directly emitted from the fibre on the surface of the tissue to be treated, here identifies as a tooth T, while in a second embodiment the light radiation is focussed on a limited area of the said surface by means of a focussing assembly, generally indicated 30, which is arranged to focus light radiation on the end of the fibre section proximate to the contact tip 22.
  • the apparatus comprises a high power Thulium doped fibre laser with emission tunable at a wavelength in the range between 1400nm and 2400nm, preferably in the range between 1800nm and 2200nm and most preferably operating at the specific wavelength of 1940nm.
  • the high absorption coefficient of the water in this range gives the possibility of the ablation of hard tissues owing to the small water content of tissues.
  • an external water flux can be supplied to enhance the superficial absorption and cool the tissue, whenever necessary.
  • the laser action is assisted with water, which may be supplied in form of spray, of small drops or of water jet.
  • the laser radiation is preferably generated with an overall power level enough to overtake the ablation threshold, which also depends on the optical coupling of the radiation on the sample, and generally is exceeding 2OW in pulsed operating mode.
  • the duration of the pulses can vary between several picoseconds to several milliseconds and preferably between l ⁇ s and 50,000 ⁇ s. Its repetition rate, if the cutting of the surface to be treated must be continuous, may range between 1 and 10,000 pulses per second, and is preferably higher than 10Hz.
  • the system can operate by single burst or with a low repetition rate.
  • the laser system has to focus the beam on the dental tissue, in order to limit the extension of the treated zone and offer a good precision to the operator during the cutting, while at the same time exceed the ablation threshold.
  • a beam diameter at the target site in the range can vary in the range of 10-5000 ⁇ m, the laser spot preferably varying between lOO ⁇ m and 500 ⁇ m.
  • the energy of a laser pulse in focused conditions is defined by the relation:
  • E L P L -t L
  • P L the power of the laser
  • t L the duration of the pulse.
  • the pulse energy is preferably comprised between 0. ImJ to 5J.
  • the described apparatus according to the invention can also be equipped with a system (not shown) for cooling the surface to be treated.
  • the advantages of an high power Thulium doped fibre laser with respect to previous technology include the possibility of exploiting a new wavelength.
  • a compact arrangement may also be obtained, for instance by using very thin and flexible optical fibres compared with a prior art Er: YAG laser.
  • the apparatus may occupy a volume that is approximately 10 times smaller, and may be approximately 5 times lighter than a laser having a conventional architecture (Erbium in YAG) .
  • the extremely limited dimensions of the apparatus allow it to be accommodated source within a hand-piece to be held in the surgeon's hand.
  • An all-fibre optical system both for generating and modulating the useful signal and for guiding it to the tissue area to be treated, also guarantees operation of the apparatus without a cooling system as well as without maintenance, which are on the contrary necessary with bulky prior art systems.
  • Suppliers guarantee fibre lasers for approximately 10 billion pulses, equivalent to an operating life of approximately 8 years.
  • crystal lasers require maintenance over a period ranging from 1 to 3 years, e.g. to replace the lamp and the crystal, for realignment, et cetera.
  • the laser radiation is produced inside the fibre allowing an easier access to a dental hand-piece. Small core fibres can be used without the addition of external optical elements, still a high intensity radiation can be easily achieved.
  • a higher electro-optical efficiency significantly reduces the consumption of electric power and the need for cooling.
  • the typical efficiency of semiconductor pumping lasers is higher than that of optical-pumping lasers, by a factor that varies from 5 to It will be evident to the person skilled in the art that the apparatus and method described hereinabove can be referred to several fields of medicine, with the appropriate technical refinements entailed by the tissue to be treated, which arise from the knowledge and practice in the field.
  • the apparatus according to the invention can be used not only in dentistry, as described extensively, but also more generally in the surgery of hard tissues (such as for example bones) when it is necessary to treat these tissues precisely and without damaging other more sensitive tissues, or without causing pain.

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Plasma & Fusion (AREA)
  • Mechanical Engineering (AREA)
  • Epidemiology (AREA)
  • Dentistry (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Dental Tools And Instruments Or Auxiliary Dental Instruments (AREA)
  • Laser Surgery Devices (AREA)

Abstract

La présente invention concerne un appareil chirurgical (10) et un procédé de traitement de tissus osseux biologiques, basés sur une structure de guide d'ondes à fibres optiques (12). Ladite structure inclut une source de radiations lumineuses cohérentes, comprenant une section de fibres dopée avec un élément de lanthanide, en particulier le thulium, afin de former une région active (14). Ladite région active est disposée de manière à émettre des photons à des longueurs d'ondes optiques comprises dans la plage allant de 1 400 nm à 2 400 nm, et de préférence à la longueur d'ondes égale à 1 940 nm. Ladite structure comprend également une section de guide d'ondes de fibres optiques (20) s'étendant au-delà de la région active, destinée à guider la radiation lumineuse sur la surface du tissu (T) devant être traité.
PCT/IB2006/054738 2006-12-11 2006-12-11 Appareil chirurgical et procédé de traitement de tissus osseux biologiques, en particulier pour la chirurgie dentaire, basés sur un laser à fibre WO2008072033A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/IB2006/054738 WO2008072033A1 (fr) 2006-12-11 2006-12-11 Appareil chirurgical et procédé de traitement de tissus osseux biologiques, en particulier pour la chirurgie dentaire, basés sur un laser à fibre

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/IB2006/054738 WO2008072033A1 (fr) 2006-12-11 2006-12-11 Appareil chirurgical et procédé de traitement de tissus osseux biologiques, en particulier pour la chirurgie dentaire, basés sur un laser à fibre

Publications (1)

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WO2008072033A1 true WO2008072033A1 (fr) 2008-06-19

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Country Status (1)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010022985A1 (fr) * 2008-08-29 2010-03-04 Starmedtec Gmbh Dispositif laser multifonction
US9011417B2 (en) 2012-05-14 2015-04-21 Convergent Dental, Inc. Apparatus and method for controlled fluid cooling during laser based dental treatments
US9408673B2 (en) 2011-09-02 2016-08-09 Convergent Dental, Inc. Laser based computer controlled dental preparation system

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5020995A (en) 1989-01-18 1991-06-04 Guy Levy Surgical treatment method and instrument
DE4029530A1 (de) * 1990-09-18 1992-03-19 Steiger Erwin Modular aufgebauter, gepulster mehrwellenlaengen-festkoerperlaser fuer medizinische anwendungen
DE9208617U1 (fr) * 1992-06-26 1992-09-10 Steiger, Erwin, Dipl.-Phys., 8038 Groebenzell, De
US5257935A (en) * 1988-03-14 1993-11-02 American Dental Laser, Inc. Dental laser
US5415652A (en) * 1991-08-28 1995-05-16 Siemens Aktiengesellschaft Method and apparatus for the treatment of hard biological material, such as hard dental material using lasers
DE19731730A1 (de) * 1996-07-24 1998-01-29 Shinji Kokubu Lasersonde
US20030053776A1 (en) * 2001-09-20 2003-03-20 Dejneka Matthew J. Apparatus and method for thermally tuning an optical amplifier

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5257935A (en) * 1988-03-14 1993-11-02 American Dental Laser, Inc. Dental laser
US5020995A (en) 1989-01-18 1991-06-04 Guy Levy Surgical treatment method and instrument
DE4029530A1 (de) * 1990-09-18 1992-03-19 Steiger Erwin Modular aufgebauter, gepulster mehrwellenlaengen-festkoerperlaser fuer medizinische anwendungen
US5415652A (en) * 1991-08-28 1995-05-16 Siemens Aktiengesellschaft Method and apparatus for the treatment of hard biological material, such as hard dental material using lasers
DE9208617U1 (fr) * 1992-06-26 1992-09-10 Steiger, Erwin, Dipl.-Phys., 8038 Groebenzell, De
DE19731730A1 (de) * 1996-07-24 1998-01-29 Shinji Kokubu Lasersonde
US20030053776A1 (en) * 2001-09-20 2003-03-20 Dejneka Matthew J. Apparatus and method for thermally tuning an optical amplifier

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010022985A1 (fr) * 2008-08-29 2010-03-04 Starmedtec Gmbh Dispositif laser multifonction
EP2965706A1 (fr) * 2008-08-29 2016-01-13 Starmedtec GmbH Dispositif laser multifonction
US9408673B2 (en) 2011-09-02 2016-08-09 Convergent Dental, Inc. Laser based computer controlled dental preparation system
US10631951B2 (en) 2011-09-02 2020-04-28 Convergent Dental, Inc. Laser based computer controlled dental preparation system
US9011417B2 (en) 2012-05-14 2015-04-21 Convergent Dental, Inc. Apparatus and method for controlled fluid cooling during laser based dental treatments
US9011416B2 (en) 2012-05-14 2015-04-21 Convergent Dental, Inc. Apparatus and method for controlled fluid cooling during laser based dental treatments
US10045833B2 (en) 2012-05-14 2018-08-14 Convergent Dental, Inc. Apparatus and method for controlled fluid cooling during laser based dental treatments

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