Dental gels

Knoll-Kohler E Metronidazole dental gel as an alternative to scaling and root planing in the treatment of localized adult periodontitis. Is its efficacy proved Eur J Oral Sci 1999 107 415— 421. 

FIGURE 5.4 Uptake of RP (0.1%) and formation of retinol from dental gel into BMCs. 

The statistical evaluation by means of fhe four-point parallel line assay resulted for the Aronal forte toothpaste in a significant higher activity of factor 1.11 (C.l. 1.03-1.19 p = 0.05) in comparison to the dental gel standard. The evaluation carried out on the quality of the experiment... 

For skin disinfection, chlorhexidine has been formulated as a 0.5% w/v solution in 70% v/v ethanol and, in conjunction with detergents, as a 4% w/v surgical scrub. Chlorhexidine salts may also be used in topical antiseptic creams, mouthwashes, dental gels, and in urology for catheter sterilization and bladder irrigation. 

Cold set, clear, gel formation with divalent cations Alginate Re-formed fruit pieces Dental gels... 

Dental gel Mouthwash Oropharynx Formulation Preparation Muco-adhesive... 

Fluoride mouthwashes are examples of preparations for dental use. Dental solutions in general have the advantage that mouthwashes are easy to use by the patient. Semisolid dental gels can be applied to specific places on the teeth. Normally this is done by the dentist or dental hygienist. An example is a hydrogel with phosphoric acid, used in etching teeth enamel to facilitate composite restoration. 

When the gel is intended mainly for the gums or the teeth pockets, a low pH is not needed. In this case poloxamers are an alternative to cellulose derivatives. The thermoreversible viscosity of poloxamer gels can be used in the preparation and administration of a dental gel with metronidazole (Table 7.8). 

Table 7.9 Phosphoric Acid Dental Gel for Etching [23] Table 7.10 Glycerated Gelatine Suppositories [24] ...

Dental gels often contain a taste correction. An overview of flavourings can be found in Sect. 5.4.10. 

In many dental gels a colouring agent is needed to obtain a contrast between gel and teeth. For instance methylene blue (methylthionine) is used in phosphoric acid gel [23]. For an overview of water soluble dyes see Sect. 23.11. 

Fluoride dental gel may be packed in a coated aluminium tube (see Sect. 24.4.8) or in a plastic bottle with a dosing pump or spraying device. For phosphoric acid gel a plastic bottle with a dosing device or a syringe with a cap is the... 

Hydrogen peroxide Dental gels Sensors Sensors NIR... 

The setting reaction of dental silicate cement was not understood until 1970. An early opinion, that of Steenbock (quoted by Voelker, 1916a,b), was that setting was due to the formation of calcium and aluminium phosphates. Later, Ray (1934) attributed setting to the gelation of silicic acid, and this became the received opinion (Skinner Phillips, 1960). Wilson Batchelor (1968) disagreed and concluded from a study of the acid solubility that the dental silicate cement matrix could not be composed of silica gel but instead could be a silico-phosphate gel. However, infrared spectroscopy failed to detect the presence of P-O-Si and P-O-P bonds (Wilson Mesley, 1968). 

In a study of dental silicate cements, Kent, Fletcher Wilson (1970) used electron probe analysis to study the fully set material. Their method of sample preparation varied slightly from the general one described above, in that they embedded their set cement in epoxy resin, polished the surface to flatness, and then coated it with a 2-nm carbon layer to provide electrical conductivity. They analysed the various areas of the cement for calcium, silicon, aluminium and phosphorus, and found that the cement comprised a matrix containing phosphorus, aluminium and calcium, but not silicon. The aluminosilicate glass was assumed to develop into a gel which was relatively depleted in calcium. 

The senior author first became interested in acid-base cements in 1964 when he undertook to examine the deficiencies of the dental silicate cement with a view to improving performance. At that time there was much concern by both dental surgeon and patient at the failure of this aesthetic material which was used to restore front teeth. Indeed, at the time, one correspondent commenting on this problem to a newspaper remarked that although mankind had solved the problem of nuclear energy the same could not be said of the restoration of front teeth. At the time it was supposed that the dental silicate cement was, as its name implied, a silicate cement which set by the formation of silica gel. Structural studies at the Laboratory of the Government Chemist (LGC) soon proved that this view was incorrect and that the cement set by formation of an amorphous aluminium phosphate salt. Thus we became aware of and intrigued by a class of materials that set by an acid-base reaction. It appeared that there was endless scope for the formulation of novel materials based on this concept. And so it proved. 

On the basis of the sol-gel process, much more attention has been paid to silicate-containing Class II hybrids, also referred to as organically modified silicas, ormosils. In this section, the synthesis of some of the most characteristic ormosils for bone and dental applications are described. 

The use of high-concentration gels and varnishes has been practised clinically for many years by dentists and dental hygienists [180]. When originally formulated, they were designed to be used in application procedures based on the concept that fluoride becomes incorporated into the crystalline phase of the enamel and leads to the development of a more acid-resistant form of apatite. They were not expected to make any difference to the levels of fluoride in saliva, or to influence the demineralisation/dissolution phase of the behaviour of tooth mineral. 

A very early study suggested that fluoride uptake was enhanced in a low pH environment [180]. Because of this, fluoride gels are often formulated to be quite acidic, typically of pH around 3. Typical products include an acidic phosphate fluoride gel that is 1.23% fluoride (equivalent to 12,300 ppm), an acidic sodium fluoride gel (0.5% fluoride, 5000 ppm) and a stannous fluoride gel (0.15% fluoride, 1000 ppm) [183]. All of these formulations are acidic, and are generally designed for use by dental professionals. There are also products for home use, which are also on the acid side of neutral, and which also contain high levels of fluoride [184]. 

Fluoride-containing varnishes are designed to be painted onto the teeth and retained for a few hours at least, during which they release fluoride close to the tooth surface [188], Like fluoride gels, they are intended for use by dental professionals, but have the advantage that they are considered to be easy to apply. They have an acceptable taste and contain lower amounts of fluoride than gels. They contain either sodium fluoride or difluorosilane as the active ingredient. 

A liquid gel preparation of ibuprofen, 400 mg, provides prompt relief and good overall efficacy in postsurgical dental pain. 

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