Fitting acrylic occlusal splints and an experimental laminated appliance used in migraine prevention therapy.

OBJECTIVE: To evaluate clinical procedures and chair time required to seat and adjust hard, heat-cured acrylic occlusal splints and an alternative laminated appliance developed to simplify construction of migraine prevention appliances. DESIGN AND SETTING: Single-centre study in the Oral Medicine Clinic, The Royal Hospitals, Belfast, Northern Ireland. METHOD: Questionnaires were distributed, January-May 2003, to operators fitting occlusal splints for 100 consecutive patients selected for migraine prevention therapy. Half the appliances were made in heat-polymerised acrylic with the remainder using a novel combination of ethylene vinyl acetate and light-curing urethane dimethacrylate. Information on operator experience, the nature of any fitting surface and occlusal adjustments together with an estimate of the time taken to make alterations was recorded. KEY FINDINGS: The need for adjustment to seat appliances intraorally was significantly less for migraine prevention appliances made using an experimental laminating technique. Where modifications were necessary, there was no significant difference in the chair time required to fit either the heat-cured hard or experimental laminated migraine prevention appliance. CONCLUSION: Provision of migraine prevention appliances may be more time efficient if the dental practitioner considers a laminated approach to construction.

Colour perception of laboratory-fired samples of body-coloured ceramic.

The objective of this investigation is to test by common perception, the colour fidelity of laboratory-fired samples of ceramic. Thirty-two ceramic discs were constructed in a thickness similar to that used for ceramic veneers using eight shades from each of four different manufacturers. A group of 20 'adept' observers colour matched the samples in strictly controlled viewing conditions using a Vita Lumin (Vita Zahnfabrik) shade guide. Samples were categorised as 'positive matches'(matching the expected shade), 'agreed shades' (matching an unexpected shade), or as 'unidentified shades' (no match). The Vita Lumin (Vita Zahnfabrik) colour 'value' index was used as a reference to categorise colour 'value' differences between observed and expected shade. Colour 'value' selection was divided into three groups: (1) matching colour 'value', (2) shades of higher colour 'value' than expected or (3) shades of lower colour 'value' than expected. Only six of the 32 samples examined were perceived to be 'positive matches' with the recommended shade guide. Fourteen 'agreed shades' were found while the remaining 12 shades were regarded as 'unidentified shades'. The vast majority of observations disagreed with the manufacturers' designated shade. A significant trend was found favouring higher 'value' (lighter) shades than those specified by the manufactures. Significant differences in the pattern of shade matches and disagreements between brands were also found. Alternative shade determination systems and/or ceramic colour modifications are required if colour fidelity between the shade guide and the materials tested is to be improved.

Use of a common shade guide to test the perception of differences in the shades and value by members of the dental team.

PURPOSE: Commercial shade guides are frequently used for treatments where the shades of teeth are being reproduced or altered. Where differences between shade tabs and the natural teeth are small, difficulty is often experienced in determining the closest match. The purpose of this investigation is to discover whether the claimed colour differences between individual shades of one commonly used guide can be determined subjectively in clinical circumstances. BASIC PROCEDURES: Seventy dental team professionals made shade comparisons in an idealized colour-matching environment using shade guides as supplied by the manufacturer. Their arrangements by 'value' were recorded and unidentified shade tabs were matched with those on a complete guide. MAIN FINDINGS: The results showed that discrepancies existed between nominated and perceived colours, for the shade determination system tested. The shade-guide manufacturer's recommended arrangement of shade tabs ranked according to colour 'value' did not correspond to subjective perception of 'value' ordering under the conditions of the study. PRINCIPAL CONCLUSIONS: There may be no practical clinical advantage in having shades which cannot be distinguished. This study indicates that colour differences between shade tabs are not clearly perceived by members of the dental team. A careful reduction of the number of tabs in the guide tested might simplify shade selection procedures and help to standardise shade-taking.

Individualized mouth prop for dental professionals and carers.

Maintaining a high standard of dental health in children with special needs, particularly those who are unable to control mandibular activity, can prove difficult and time consuming for parents, carers and dental professionals. This article describes the construction of an individually made and relatively unobtrusive finger guard mouth prop, designed to facilitate intraoral examination and oral hygiene care for these children. An initial evaluation by a number of users found these mouth props were simple to fit, stable and provided adequate finger protection. All users planned to continue using their mouth prop after the trial period. It is concluded that similar finger mounted mouth props may help facilitate dental care and oral hygiene for children requiring special care.

Pharmacological evaluation of selected, orally active, peptidyl inhibitors of human neutrophil elastase.

Human neutrophil elastase (HNE) is a serine proteinase capable of degrading a number of connective tissue macromolecules and has been implicated in the destructive processes associated with several chronic inflammatory diseases. A large series of peptidyl electrophilic ketones have been shown to be potent inhibitors of HNE in vitro and in vivo. We report the pharmacology and pharmacokinetics of selected inhibitors from this series. MDL 101, 146, MDL 102, 111, MDL 102,823 and MDL 100,948A are -Val-Pro-Val-pentafluoroethylketones with various amino-terminal protecting groups. Although their Ki values varied considerably, (25-170 nM), these compounds demonstrated similar ED50 values after oral administration in the HNE-induced hemorrhage model in hamsters and rats. The duration of action of MDL 102,111 was shorter than that of the other analogs in the HNE-induced pulmonary hemorrhage model in both species. The duration of action of all of the compounds was longer in the rat than in the hamster. Isolated sections of rat jejunum were used to determine the in situ absorption of these compounds. MDL 102,111 showed the greatest extent of absorption, with MDL 102,823, MDL 100,948A and MDL 101,146 following in descending rank order. The comparative metabolic stability of these analogs was measured over a 2-hr incubation period using rat liver homogenates. MDL 101,146 was the most stable, followed by MDL 102,823, MDL 102,111 and MDL 100,948A. MDL 101,146 was more stable in a liver homogenate from rats compared with a liver homogenate from hamsters.(ABSTRACT TRUNCATED AT 250 WORDS)