Biomaterial Database

Investigation into the optimum beam shape and fluence for selective ablation of dental calculus at lambda = 400 nm. 2010

Joshua E Schoenly, and Wolf Seka, and Peter Rechmann

Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA. jscho@lle.rochester.edu

OBJECTIVE A frequency-doubled Ti:sapphire laser is shown to selectively ablate dental calculus. The optimal transverse shape of the laser beam, including its variability under water-cooling, is determined for selective ablation of dental calculus. METHODS Intensity profiles under various water-cooling conditions were optically observed. The 400-nm laser was coupled into a multimode optical fiber using an f = 2.5-cm lens and light-shaping diffuser. Water-cooling was supplied coaxially around the fiber. Five human tooth samples (four with calculus and one pristine) were irradiated perpendicular to the tooth surface while the tooth was moved back and forth at 0.3 mm/second, varying between 20 and 180 iterations. The teeth were imaged before and after irradiation using light microscopy with a flashing blue light-emitting diode (LED). An environmental scanning electron microscope imaged each tooth after irradiation. RESULTS High-order super-Gaussian intensity profiles are observed at the output of a fiber coiled around a 4-in. diameter drum. Super-Gaussian beams have a more-homogenous fluence distribution than Gaussian beams and have a higher energy efficiency for selective ablation. Coaxial water-cooling does not noticeably distort the intensity distribution within 1 mm from the optical fiber. In contrast, lasers focused to a Gaussian cross section (< or =50-microm diameter) without fiber propagation and cooled by a water spray are heavily distorted and may lead to variable ablation. Calculus is preferentially ablated at high fluences (> or =2 J/cm(2)); below this fluence, stalling occurs because of photo-bleaching of the calculus. Healthy dental hard tissue is not removed at fluences < or =3 J/cm(2). CONCLUSIONS Supplying laser light to a tooth using an optical fiber with coaxial water-cooling is determined to be the most appropriate method when selectively removing calculus with a frequency-doubled Ti:sapphire laser. Fluences over 2 J/cm(2) are required to remove calculus efficiently since photo-bleaching stalls calculus removal below that value.

UI	MeSH Term	Description	Entries
D003728	Dental Calculus	Abnormal concretion or calcified deposit that forms around the teeth or dental prostheses.	Tartar,Calculus, Dental
D003739	Dental Cementum	The bonelike rigid connective tissue covering the root of a tooth from the cementoenamel junction to the apex and lining the apex of the root canal, also assisting in tooth support by serving as attachment structures for the periodontal ligament. (Jablonski, Dictionary of Dentistry, 1992)	Cementoblasts,Cementum,Cementoblast,Cementum, Dental
D003743	Dental Enamel	A hard thin translucent layer of calcified substance which envelops and protects the dentin of the crown of the tooth. It is the hardest substance in the body and is almost entirely composed of calcium salts. Under the microscope, it is composed of thin rods (enamel prisms) held together by cementing substance, and surrounded by an enamel sheath. (From Jablonski, Dictionary of Dentistry, 1992, p286)	Enamel,Enamel Cuticle,Dental Enamels,Enamel, Dental,Enamels, Dental,Cuticle, Enamel,Cuticles, Enamel,Enamel Cuticles,Enamels
D004735	Energy Transfer	The transfer of energy of a given form among different scales of motion. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed). It includes the transfer of kinetic energy and the transfer of chemical energy. The transfer of chemical energy from one molecule to another depends on proximity of molecules so it is often used as in techniques to measure distance such as the use of FORSTER RESONANCE ENERGY TRANSFER.	Transfer, Energy
D004867	Equipment Design	Methods and patterns of fabricating machines and related hardware.	Design, Equipment,Device Design,Medical Device Design,Design, Medical Device,Designs, Medical Device,Device Design, Medical,Device Designs, Medical,Medical Device Designs,Design, Device,Designs, Device,Designs, Equipment,Device Designs,Equipment Designs
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D012534	Dental Scaling	Removal of dental plaque and dental calculus from the surface of a tooth, from the surface of a tooth apical to the gingival margin accumulated in periodontal pockets, or from the surface coronal to the gingival margin.	Root Scaling,Scaling, Dental,Scaling, Root,Scaling, Subgingival,Scaling, Supragingival,Root Scalings,Scalings, Root,Subgingival Scaling,Supragingival Scaling
D046509	Tissue Culture Techniques	A technique for maintaining or growing TISSUE in vitro, usually by DIFFUSION, perifusion, or PERFUSION. The tissue is cultured directly after removal from the host without being dispersed for cell culture.	Culture Technique, Tissue,Culture Techniques, Tissue,Tissue Culture Technique
D053685	Laser Therapy	The use of photothermal effects of LASERS to coagulate, incise, vaporize, resect, dissect, or resurface tissue.	Laser Knife,Laser Scalpel,Surgery, Laser,Vaporization, Laser,Laser Ablation,Laser Knives,Laser Photoablation of Tissue,Laser Surgery,Laser Tissue Ablation,Nonablative Laser Treatment,Pulsed Laser Tissue Ablation,Ablation, Laser,Ablation, Laser Tissue,Knife, Laser,Knifes, Laser,Knive, Laser,Knives, Laser,Laser Knifes,Laser Knive,Laser Scalpels,Laser Surgeries,Laser Therapies,Laser Treatment, Nonablative,Laser Treatments, Nonablative,Laser Vaporization,Nonablative Laser Treatments,Scalpel, Laser,Scalpels, Laser,Surgeries, Laser,Therapies, Laser,Therapy, Laser,Tissue Ablation, Laser
D053844	Lasers, Solid-State	Lasers which use a solid, as opposed to a liquid or gas, as the lasing medium. Common materials used are crystals, such as YAG (YTTRIUM aluminum garnet); alexandrite; and CORUNDUM, doped with a rare earth element such as a NEODYMIUM; ERBIUM; or HOLMIUM. The output is sometimes additionally modified by addition of non-linear optical materials such as potassium titanyl phosphate crystal, which for example is used with neodymium YAG lasers to convert the output light to the visible range.	Alexandrite Laser,Alexandrite Lasers,Diode Pumped Solid State Laser,Diode Pumped Solid State Lasers,Er-YAG Laser,Er-YAG Lasers,Erbium Doped Yttrium Aluminum Garnet Laser,Erbium YAG Laser,Erbium-Doped Yttrium Aluminum Garnet Laser,Erbium-Doped Yttrium Aluminum Garnet Lasers,Ho YAG Laser,Ho YAG Lasers,Holmium Doped Yttrium Aluminum Garnet Lasers,Holmium Laser,Holmium-YAG Laser,Holmium-YAG Lasers,KTP Laser,Laser, Nd-YAG,Nd-YAG Laser,Nd-YAG Lasers,Neodymium-Doped Yttrium Aluminum Garnet Laser,Neodymium-Doped Yttrium Aluminum Garnet Lasers,Potassium Titanyl Phosphate Laser,Ruby Laser,Ruby Lasers,Solid-State Laser,YAG Laser,YAG Lasers,YLF Laser,YLF Lasers,YSGG Laser,YSGG Lasers,Yttrium Aluminum Garnet Laser,Yttrium-Lithium-Fluoride Laser,Yttrium-Lithium-Fluoride Lasers,Yttrium-Scandium-Gallium Garnet Laser,Yttrium-Scandium-Gallium Garnet Lasers,Erbium YAG Lasers,Holmium Lasers,KTP Lasers,Lasers, Alexandrite,Lasers, Diode Pumped Solid State,Lasers, Er-YAG,Lasers, Erbium-Doped Yttrium Aluminum Garnet,Lasers, Ho-YAG,Lasers, Holmium Doped Yttrium Aluminum Garnet,Lasers, Nd-YAG,Lasers, Neodymium-Doped Yttrium Aluminum Garnet,Lasers, Ruby,Lasers, YAG,Lasers, Yttrium Aluminum Garnet,Lasers, Yttrium-Lithium-Fluoride,Potassium Titanyl Phosphate Lasers,Yttrium Aluminum Garnet Lasers,Er YAG Laser,Er YAG Lasers,Erbium Doped Yttrium Aluminum Garnet Lasers,Ho-YAG Laser,Ho-YAG Lasers,Holmium YAG Laser,Holmium YAG Lasers,Laser, Alexandrite,Laser, Er-YAG,Laser, Erbium YAG,Laser, Ho YAG,Laser, Ho-YAG,Laser, Holmium,Laser, Holmium-YAG,Laser, KTP,Laser, Nd YAG,Laser, Ruby,Laser, Solid-State,Laser, YAG,Laser, YLF,Laser, YSGG,Laser, Yttrium-Lithium-Fluoride,Laser, Yttrium-Scandium-Gallium Garnet,Lasers, Er YAG,Lasers, Erbium Doped Yttrium Aluminum Garnet,Lasers, Erbium YAG,Lasers, Ho YAG,Lasers, Holmium,Lasers, Holmium-YAG,Lasers, KTP,Lasers, Nd YAG,Lasers, Neodymium Doped Yttrium Aluminum Garnet,Lasers, Solid State,Lasers, YLF,Lasers, YSGG,Lasers, Yttrium Lithium Fluoride,Lasers, Yttrium-Scandium-Gallium Garnet,Nd YAG Laser,Nd YAG Lasers,Neodymium Doped Yttrium Aluminum Garnet Laser,Neodymium Doped Yttrium Aluminum Garnet Lasers,Solid State Laser,Solid-State Lasers,YAG Laser, Erbium,YAG Laser, Ho,YAG Lasers, Erbium,YAG Lasers, Ho,Yttrium Lithium Fluoride Laser,Yttrium Lithium Fluoride Lasers,Yttrium Scandium Gallium Garnet Laser,Yttrium Scandium Gallium Garnet Lasers