Лако-красочные материалы — производство

The development of luting agents with ever more satisfactory bonding characteristics has been an ongoing objective in dental materials research for many decades. Although numerous adhesive compositions have been, and continue to be, commercialized, no perfect universal bonding systems have as yet reached the market. Important classes of luting materials include the zinc phosphate and […]

A luting agent should have minimal solubility in the aqueous oral fluids while displaying good wetting properties. It should possess low initial viscosity to allow for proper seating of the restoration and for adequate narrowing of the margin between restoration and tooth. A wide margin, commensurate with a thick layer of poorly flowing, viscous cement […]

Cements are adhesive substances capable of bonding different bodies together; they are generally applied as liquids or viscous fluids, which set (harden, cure) in situ to solid materials. Dental cements used for luting or cavity lining are similar in composition and related in function; accordingly, certain data presented here are pertinent as well to Section […]

Eberhard W. Neuse and Eliakim Mizrahi University of the Witwatersrand, Johannesburg, South Africa I. INTRODUCTION The success of modern restorative dentistry in the repair, restoration, and replacement of tooth structure is critically dependent on the availability of specialized metallic and non­metallic materials and on procedures for their proficient application. Most of the non — metallics […]

Drug delivery to the eyes is made difficult by dilution of drug in the tears and the natural mechanisms of blinking and high tear turnover rate, which protect the eye from external contaminants. Traditional aqueous, ocular delivery systems are administered dropwise, and due to the foregoing conditions, bioavailability is severely limited for either local or […]

Drug administration to the oral cavity has many advantages from both a patient and a therapeutic point of view. Both local and systemic availability can be achieved using bioadhesives in the oral cavity. Anesthetic, anti-inflammatory, and antimicrobial agents can be administered locally for increased residence time using bioadhesives. Besides the use of adhesives for retention […]

The vaginal and cervical route of administration is unique from other routes in that the tissue environment is subject to many changes throughout a women’s life. Depending on whether the woman is pre — or postmenopausal, the tissue and mucus of the vaginal and cervical areas can be vastly different. Decreased endogenous levels of estrogen, […]

Nasal delivery systems are usually in the form of aqueous sprays in which the drug is distributed into the nasal cavity. This area provides an excellent route for drug absorp­tion because of its large surface area and vascularity [58] as well as a thin layer of mucus secreted from local mucosal glands [59]. Absorption into […]

Most recently administered drugs for either local or systemic therapy are given in suppository form. Systemic availability of rectally administered drugs is maximal when the dosage form is close to the anus [51]. Normally, after insertion, suppositories tend gradually to migrate and rest in the upper portion of the rectum. Drugs that are absorbed through […]

Most drug delivery systems are taken orally with the absorption of the drug occurring mainly in the proximal small intestine. To be effective either locally or systematically, a bioadhesive drug delivery system must be able to overcome the harsh gastric environment, motility of the gastrointestinal (GI) tract, immunogenic responses, enzymatic degradation, and dynamic changes in […]