CLINICAL APPLICATION RESTORATIVE DENTISTRY รศ. ป ทมา ช ยเล ศวณ ชก ล

Transcription

1 CLINICAL APPLICATION OF LASERS USED IN RESTORATIVE DENTISTRY รศ. ป ทมา ช ยเล ศวณ ชก ล

2 L IGHT A MPLIFICATION by S TIMULATED E MISSION of R ADIATION

3 Laser characteristics Monochromatic Photons stimulate photons of the same frequency, One specific color Coherent Photon waves in phase-maximum intensity, Identical amplitude Non-divergent Photons at angles to cavity axis, not stimulate others

4 Laser Output Continuous wave Chop beam to produce pulses (mechanical), Pulse can be shorter than the thermal relaxation time of the tissue (no heat transmission) Pulsed laser (higher power)

5 Electromagnetic Wave Scale Excimer XeF(351 nm) KrF (248nm) Er:YAG ( 2.94µ) Diode 980nm 2 KTP (532nm) CO (10,600 nm) Diode 812nm HeNe (632nm) ErCr:YSG G 2.78 µ Ultraviolet Infrared 100 nm Visible 400 nm 750 nm 10,000 nm ArF (193nm) Argon (488nm) Excimer XeCl (308 nm) Argon (514 nm) Nd: : YAG (1064 nm)

6 A bsorbance-useful energy R eflectance T ransmittance S cattering

7 Ablation Removal of tissue by laser energy Visible e & IR lasers - thermal process Excimer lasers photochemical process s (beak bonds)

8 Excimer laser Nonthermal lasers - interact with tissues through a photochemical process, ablation being the result of breaking bonds within tissue

9 Excimer laser Most prevalent excimer: ArF F (193 nm) produces a cleaner cut with less thermal damage in both hard & soft tissues XeCl l (308 nm) can be delivered through an optical fiber much more reliable

10 Absorption Windows nm m (UV) protein & DNA dominate absorption >2000nm m (IR) water is main absorber nm low optical absorption, high penetration

11 Calling NdYAG Neodymium-yttrium yttrium- aluminum-garnet GaAlAs Gallium-aluminum aluminum-arsenidearsenide NdYAP Neodymium-yttrium yttrium- aluminum-perovskite

12 Laser math Power - laser output expressed as watts Energy- laser output expressed as joules Fluence-laser laser energy density expressed as joules/cm 2 1 watt = 1 joule/second watts x seconds = joules

13 Dye enhanced laser ablation Increase absorption by addition of an exogenous dye on the surface of tissue Energy that would be reflected or scattered is now coupled into dye-tissue interface

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15 Clinical applications of laser in endodontics Diagnosis of pulpal blood flow Dentinal hypersensitivity Pulp capping g & pulpotomy Sterilization of root canals Root canal shaping g & obturation Apicectomy Others

16 Diagnosis of blood flow in dental pulp Laser Doppler Flowmetry (LDF) He-Ne Ne, GaAlAs, IR Low-power level of 1-2 mw

17 Light scattered by moving RBC, produce a signal that was a function of the red cell flux (vol of cells illuminated x mean cell velocity)

18 Dental hypersensitivity 2 gr : low output power (He-Ne, GaAlAs) : middle output power (Nd-YAG, CO 2 )

19 Dental hypersensitivity Low power : laser s energy is transmitted through enamel/dentine to reach the pulp : affect action potential or block depolarization of C-fiber, no damage to pulp

20 Dental hypersensitivity Middle power : laser s energy is transmitted through dentine, thermally effects & pulpal analgesia tubules odontoblasts : sealing dentinal : hyperemia : focal degeneration of

21 Pulp capping & pulpotomy Vaporize tissues, coagulate & seal small blood vessels to produce bloodless field Sterile wound surface The first laser pulpotomy was CO 2 laser NdYAG, GaAlAs, Ar

22 Sterilization of root canals NdYAG is popular because of a thin fiber-optic for entering canals NdYAG significantly reduced E.faecalis while NaOCl effectively disinfected canals (M XeCl, ErYAG, NdYAP (Moshonov et al., 1995)

23 Sterilization of root canals NdYAP + Serial prep + MM M 3000 showed the cleanest prep p (Yves Blum m & Abadie, 1997) Bactericidal effect Precautions : spreading bacterial contamination to patient t & dental team via smoke by laser : thermal injury to periodontium ium

24 Bactericidal effect Chemical rinse 100 µm Ultrasonic cleansing 1000 µm Laser Laser > 1000 µm

25 Excimer in Endodontics (in in vitro) Pini, Lasers in Surg & Med 9, 352-7, nm XeCl laser Necrotic dentine in canal walls is removed at lower fluences than healthy tissues Canal prepared in n 10 mins

26 Root canal shaping g & obturation ErYAG Weichman n & Johnson (1971) first applied CO 2 laser to seal apical foramen in vitro Removed debris s & smear layer: ErYAG is more effective than Ar or NdYAG (Matsuoka et al., 1998: Takeda et al., 1999)

27 Melt dentine e & seal exposed tubules : XeCl, ArF Ar, CO 2, NdYAG : soften gp Hard to clean all walls because the laser is emitted straight, making it impossible to irradiate the lateral walls

28 Infected teeth, postop discomfort in the laser-treated gr was significantly reduced compared to nonlaser-treated gr (Koba oba, 1995; Koba et al., 1999) Useful as an adjunct during RCT but not possible to use alone for RCT

29 AAEAE Fiber tip cannot be curved to follow the natural curvatures of the root (canals are often curved 2 dimensions) Elevation in temp can damage the tooth, soft tissue surrounding the bone

30 Apicectomy Advantage for the surgery Bloodless field Sterilization of wound Less op & post-op op pain Shorter hospital stays

31 Apicectomy Advantage for the cut surface Surface is sterilized Dentinal tubules are sealed No need for mechanical drill eliminate thermal & structural damage

32 Apicectomy CO 2 laser was first used d (Miserendino iserendino, 1988) Bader r & Lejeune (1998) showed that CO 2 did not improve the healing process NdYAG (Sumitom umitomo o & Furuya, 1988) smooth, clean resected root surfaces, improve healing g & postop discomfort Less working time than ultrasonic

33 Apicectomy

34 Others Sterilize dental instruments : Ar, CO 2, NdYAG Fused fractured root (Arakawa et al., 1996) but was not achieved Retreatment : NdYAP (Farge et al., 1998)

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36 FDA Approval for many soft tissue procedures ErYAG recently approved for cavity prep p & caries removal

37 Waterlase Technology Millennium Specifications Wavelength 2780 nanometers (Er, Cr:YSGG) Frequency 20 Hz Power W Pulse Energy 0-300mJ Operating Voltage 115~ ±10% Cooling System Air & water Erbium, chromium: yttrium scandium gallium garnet

38 Revolutionary Er, Cr: YSGG Waterlase for Hard & Soft Tissue Half size & weight of original Millennium. Elegant. Slender. Fits into any operatory. Incorporates state-of-the-art technological advances-laser design, optics, electronics, computerization & delivery system. Optimize costs, service & decrease shipping expenses.

39 YSGG Atomization Chamber Macrospheres 1.5 mm Interactive Zone Hydrokinetic Energy Waterlase Macrospheres, generated by atomization chamber, are impinged at the laser beam delivery tip, & become superkinetically energized. This causes the macrospheres to disperse whereby the energy is released in an interactive zone within 1.5 mm from the laser delivery tip. The energized macrosphere acts as cutting agent to remove the target tissue.

40 Waterlase vs Laser Comparative Clinical Evidence Optical Photomicrograph of a Human Tooth Cut produced by Waterlase with atomized water spray Cut produced by same laser with NO water spray *Both cuts were done at the same power setting with a micropositioner, controlling the rate of speed & distance to tissue.

41 Waterlase Clinical Applications Hard Tissue Procedures (Adult & pediatric patients) Cavity Prep - Cl I-V Caries Removal Roughening & Etching Enameloplasty Excavation of pits & fissures for sealants Root canal treatment Soft Tissue Procedures Gingival Recontouring Gingivectomy Frenectomy Fibroma Removal Biopsy Hemostasis Aphthous Ulcer Treatment

42 Effect on periodontal tissues Threshold level for bone survival was 47 o C (Eriksson & Albrektsson, 1983) Ankylosis, Cemental lysis, Major bone remodeling

43 Effect on periodontal tissues NdYAG produced thermal effects which could cause pulpal trauma. Water coolant was effective in reducing thermal effects (Gow et al., 1999)

44 Effect on periodontal tissues NdYAG lasing cycles of 3 J/S for 15 S followed by a 15 S recovery interval can be continued without risk of thermal damage (Ramskold et al., 1997) Q-switched nanosecond pulse mode (Kimura et al., 1997, 1998)

45 Temperature requirements CO 2 laser cooled with air-water spray produced similar pulpal temperature changes to those caused by an air-water cooled high speed drill

46 Factors related to heat generation Wavelength of laser: excimer produce less heat Absorption characteristics of exposed tissues Power density of laser Exposure time Mode - pulsed vs continuous

47 Clinical Cases

48 Xenon Bulb & Liquid Light Guide technology

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51 DIAGNOdent Sweden, 1980 Kavo Diode red light 655 nm Reduce signals in demin area 0-14: No caries 15-20: Enamel caries 21-99: Dentine caries

52 Cl V With Gingival Recontouring Pre-op Intra-op Preparation Completed Post-op Restoration Completed Photos courtesy of William A. Greider, D.M.D., M.A.G.D.

53 Cl V With Gingival Recontouring Class V where decay is located subgingivally is one of the best uses for the Millennium Two Cl V lesions located on the labial surface of teeth No. 6 & 7.

54 Cl V With Gingival Recontouring The decay is extended subgingivally so soft tissue recontouring was necessary before preparation. No anesthesia was utilized. Tissue was removed using preset no.1. The soft tissue recontouring took < 1 min & the hemostasis was completed. Preset no.4 was used to access the carious lesions. The left shows the result immediately following surgery.

55 Cl V With Gingival Recontouring The entire restoration & recontouring was performed with the BIOLASE Millennium, in < 10 min - no shots, no pain.

56 Cl I Restoration Pre-op Intra-op Preparation Completed Post-op Restoration Completed Photos courtesy of William A. Greider, D.M.D., M.A.G.D.

57 Cl I Restoration Cl I carious lesions on the occlusal surface of teeth No. 28 & 29.

58 Class I Restoration The Enamel Preset was used, carious lesions were eradicated. Anesthesia was not utilized - no shot, no pain!

59 Class I Restoration Hydrokinetic usage totaling 1 min for completed restoration.

60 SEM Scanning Electron Micrographs

61 Waterlase Millennium vs Air Abrasion Bonding surface quality for enamel Air abrasion causes smear layer & debris on enamel. SEM of enamel cut surface shows smear layer & debris. (x1000) 100 µm 100 µm Millennium Er, Cr: YSGG cuts enamel with NO smear layer, no micro fractures. SEM of enamel cut structure is compact with no column displacement & no modification of the intercolumnar distances. No smear layer or denaturated tissue structure. (x1000)

62 Waterlase Millennium vs. Air Abrasion Bonding surface quality for dentin Air abrasion causes smear layer on dentin. SEM shows smear layer covers the dentinal tubules. (x1000) 100 µm 100 µm Millennium Er, Cr: YSGG creates cuts on dentin with no smear layer. SEM shows longitudinally cut dentinal tubules which are open & free of smear layer. (x1000)

63 Waterlase Millennium vs Drill, Air Abrasion & Acid Etch SEM of enamel cut with high speed drill & etched. Notice typical etched enamel surface structure. (x2000) 10 µm *All of the above slides were performed at a magnification of x2000 on a Jeol SEM model JSM-840.

64 Waterlase Millennium vs. Drill, Air Abrasion & Acid Etch Enamel Bonding Surface Quality 10 µm SEM of enamel cut with Waterlase is similar to that of the acid etched surface. Notice the microroughness & absence of smear layer. This structure provides strong micromechanical bonding of the resin composite material to the cut surface. (x2000) *All of the above slides were performed at a magnification of x2000 on a Jeol SEM model JSM-840.

65 Cutting Hard Tissue with High-speed Drill vs Millennium Drill creates smear layer & microfracture of approximately 10 μ in width (x200) Millennium creates clean cuts on dentin. No smear layer, tubules open & free of debris (x3500)

66 Safety Appropriate eyewears Wavelength dependent Operator r & patient must be protected

67 Recommended reading Lasers in Dentistry (2003) Ishikawa I, Frame JW, Aoki A editors. International Congress Series Chailertvanitkul P, Jitpakdeebodin K, Sattayut S (200( 2001) An apical microleakage of Super EBA, Nd:YAG laser r & cold burnished gp in apicoectomy. KDJ 4 (1),

68 Recommended reading ป ทมา ช ยเล ศวณ ชก ล (2547) การประย กต ใช เลเซอร ในงานว ทยาเอนโดดอนต ดอนต. เอ นโดสาร 9 (2), patchai@kku.ac.th