Laser in Dentistry By Hisham Sindi

LASER Light Amplification by Stimulated Emission of Radiation

Stimulated VS. Spontaneous

Production of Laser Energy Active Medium Optical Resonator Energy Source

1) Active Medium Solid : (ruby and Nd: YAG) Gas : (CO2, argon and He-Ne) Liquid : (complex organic dyes) Semiconductor : (diodes) Metal vapor : (copper)

2) Optical Resonator Left mirror : Flat and full reflection Right mirror : Concave and partial transmition

Energy Source High Voltage Power Supply Radiofrequency Generator Flash Lamp Tube Another laser

Active medium Energy source Left mirror Right mirror Laser

Characteristics Coherent Parallel Monochromatic

Classification of Laser Medium Heat production Output power Pumping scheme Operation mode

According to Heat Production 1) Athermic (Soft laser) (LLL) : He-Ne 2) Thermic (Hard laser) : CO2 Nd:YAG Ruby

According to Output Power Low power : (up to 1000 mW) Middle power : (1-3 W) High power laser : (3 W and upwards)

According to Pumping Scheme Optical Electrical

According to The Operation Mode Continuous wave Pulsed

Uses of Laser Commercial Industrial Medical Research Military

1) Commercial Copiers Displays Communications Printing Scanning Light shows Compact Disk (CD)

2) Industrial Alignment Cutting Drilling Sealing Construction Soldering

3) Medical Ophthalmology Invasive Surgery Dentistry Diagnostic Cosmetic Surgery Endoscopy

4) Research Fusion Spectroscopy Velocimetry

Military Navigation Ranging Illumination Weapons

Biologic effects of Laser Light Thermal effect: Photocoagulation Photovaporization 2) Non thermal effect: Photochemical Photomechanical

Thermal Effect 36.5 C˚: No effect 37 C˚ : Photoactivation 44 C˚ : Tissue denaturation 60 C˚ : Tissue degradation Whitening of tissue surface 65 C˚ : Tissue coagulation Hemostasis and Intraluminal thrombosis Exceeding 100 C˚ : Vaporization

Sizes of Cutting Depend on: Thermal conduction of the tissue The wave length The power of energy

Non Thermal Effect Photochemical : Neural Activation of enzymes (ATP) Cell membrane 2) Photomechanical (Nd-YAG) : Extremely high power ultra short pulses.

Laser in Dentistry

Pulsed Nd-YAG Lasers 1) Soft tissue : Gingival retraction Gingivectomy Gingivoplasty Frenectomies Apthus ulcers 2) Hard tissue: Enamel and dentin etching Dentin Hypersensitivety Caries detection Endodontic treatment (shaping, sterilization and obturation)

Argon Lasers (476, 488, 514 nm) Cure dental bonding agent and composite resin. Recommended for many soft tissue application

CO2 Lasers (10600 nm) Superficial cutting or vaporizing soft tissue. Oral and maxillofacial surgery Minimal photocoagulation in deeper tissues

Er-YAG Lasers Strongly absorbed by collagen, hydroxyapatite and water Caries removal and cavity preparation Hard dental tissue Cut and vaporize with small zones.

Effects of Lasers on Dental Tissues Enamel Dentin Cementum Pulp Wound healing

Effect on Enamel Modification of the enamel surface Melting structural elements Increase caries resistance

Effect on Dentin Sealing of dentinal tubules Decrease dentin permeability Desensitization of dentin

Effect on Cementum Increase resistance Reduction of plaque accumulation Calculus removal

Effects in Wound Healing Rapid epithelization Increase collagen Neovasculrization Neural regeneration Haemostatsis

Safety Measures Protective glasses Cover reflective surfaces Wet gauze pads Remove anesthetic gases Suction smoke and vaporized soft tissue

Contraindications Pregnancy Heart diseases

Examples Diagnodent Waterlase

Thank You