ABSTRACT
The first dental laser for use in cutting human teeth in vivo was cleared by the Food and Drug Administration for marketing in the United States. The authors explored, in summary form, the data provided to the FDA for the clinical use of the erbium:yttrium-aluminum-garnet, or Er:YAG, laser. The authors concluded that using the Er:YAG laser to treat dental hard tissue is both safe and effective for caries removal, cavity preparation and enamel etching.
Subject(s)
Laser Therapy , Tooth/surgery , Adolescent , Adult , Aluminum Silicates , Analysis of Variance , Anesthesia, Dental , Child , Dental Caries/surgery , Dental Cavity Preparation/methods , Dental Enamel/surgery , Dental High-Speed Equipment , Dental Pulp/pathology , Dentin/surgery , Dentistry/trends , Erbium , Follow-Up Studies , Forecasting , Humans , Middle Aged , Safety , Single-Blind Method , United States , United States Food and Drug Administration , YttriumABSTRACT
OBJECTIVE: We determined that the Er:YAG pulsed 2.94 micron radiation was successful in the removal of caries, cavity preparation, and etching prior to acid etching. SUMMARY BACKGROUND DATA: The laser group was compared to a control group in which the high-speed drill was employed. Parameters measured included histological evaluation of the pulp, scanning electron microscopy of the surface morphology of the tooth, dye penetration studies, bond strength measurements, and rating of the laser's ability to remove caries and form the preparation. METHODS: We collectively evaluated 60 patients with 106 teeth in both the laser and control groups over a 1-year period. Teeth were treated in vivo and then extracted immediately, at 2 days, 1 month, and up to 1-year to assess pulpal healing, surface morphology, and the quality of the preparation, restoration, and pain. RESULTS: The dental laser was shown to be equal or better than the drill in the tested procedures of caries removal, cavity preparation, and etching prior to acid etching. The scanning electron microscopy revealed no microfracturing, open dentinal tubules, and effective etching with the laser having a mean of 2.7 with an optimum rating of 3. The histological testing confirmed that the pulp was not compromised using the laser with scores of theta for hemorrhage, 0.47 for hyperemia, and 0.12 for inflammation on a scale of 0 to 3 where 0 is no effect. CONCLUSIONS: The FDA has recently cleared the Er:YAG to remove all classes of caries, form the cavity preparation, and modify the enamel and dentin prior to acid etching. In this Phase I study conducted as part of the clinical trials, there were no complications and no tooth was compromised. Patients were consistently treated without anesthesia with the same or better results than the drill as confirmed by scanning electron microscopy and histological studies.
Subject(s)
Dental Caries/therapy , Dental Cavity Preparation/instrumentation , Laser Therapy , Adolescent , Adult , Child , Dental Caries/classification , Dental Cavity Preparation/methods , Dental High-Speed Equipment , Dental Pulp/radiation effects , Dentin/radiation effects , Erbium , Female , Humans , Male , Microscopy, Electron, Scanning , Middle AgedABSTRACT
Numerous studies have been carried out on drug-polymer sustained release systems designed for implantation. The majority of these efforts have been directed toward determining the in-vitro rate of drug release from specific systems or drug polymer combinations and the in-vivo studies have attempted to utilize analysis of the blood serum and excretory products as a measure of the release rate and behavior. To gain a better understanding of the influence of the local tissue environment and implant site on release behavior, we have investigated the release behavior of a gentamicin-silicone rubber system implanted in canines. Particular attention has been directed toward investigating the role that the fibrous capsule which eventually surrounds the implant plays in determining the rate and pattern of drug release. The drug burst effect was decreased by the use of a drug-free silicone rubber membrane on the gentamicin-silicone rod implant. Analysis for gentamicin in the tissue adjacent to the implant for periods up to four weeks indicated that the release rate was retarded by the development of the fibrous capsule. The temporal and spatial variations in gentamicin levels in the tissue surrounding the rod implants were determined. In addition, the influence of implant coating and gentamicin loading level in the implant on local tissue concentrations with time were also investigated. These studies provide evidence that the fibrous capsule surrounding a drug-polymer sustained release implant may influence the release behavior of the drug in an advantageous or disadvantageous manner depending upon the desired function of the sustained release system.