Influence of tongue position on the determination of tooth shade.

STATEMENT OF PROBLEM: Dentists frequently use electronic devices to determine tooth color. However, neither the instructions for these devices nor the accompanying brochures refer to the environmental conditions required at the point of measurement. PURPOSE: The purpose of this multicenter prospective clinical study was to reveal whether a change in the oral background influences tooth color determination. MATERIAL AND METHODS: Students (N=42) at the dental clinic in Berlin, Leipzig, Greifswald and Olomouc (women n=27, men n=15) participated in this study. It was their first contact with the spectral photometer (Easyshade Advance 4.0; VITA Zahnfabrik). After a short introduction on how to use the device, the students made 1-point measurements on the same patient on the maxillary central incisor. In the first measurement, the patient's mouth was open, and the palatal surface uncovered. In the second measurement, the patient's mouth was closed slightly, and the tongue pressed on the lingual surface of the maxillary central incisor. The mean ±SD and the 95% confidence interval (95 % CI) were calculated using the Student t test for each test series (α=.05). RESULTS: Statistical evaluation of the 2 measurements revealed changes in the L*a*b* values with a mean L*=0.204, a*=-0.351, and b*=0.02; a median of 0.4, -0.3, and -0.1, respectively; a ±SD of 2.37, 0.64, and 0.89, respectively; and 95% CIs of L*=-0.476 to 0.884, a*=-0.531 to -0.702, and b*=-0.23 to 0.52, respectively. These differences were not statistically significant (P>.05). The measurements of L*, a*, and b* with and without tongue coverage of the lingual surfaces of the maxillary teeth did not show any statistically significant differences (P=.663). CONCLUSIONS: The results demonstrate that the position of the tongue does not influence measurement accuracy during the application of the Easyshade Advance device.

Oral lichenoid lesions and allergy to dental materials.

BACKGROUND: Dental materials, oral hygiene products and food additives may cause contact allergic reactions in the mouth with varied clinical presentation. Oral lichenoid lesions (lichen planus-like lesions) can be induced by hypersensitivity to dental restorative metals, acrylates, flavorings and other substances. AIM: The aim of this study was to demonstrate contact allergy to dental materials in patients with oral lichenoid lesions using patch tests. PATIENTS AND METHODS: Routine patch tests with two sets of allergens - "European Standard" and "Dental Screening" (Chemotechnique Diagnostics, Sweden) supplemented with pulverized amalgam, iridium, indium, menthol, sorbic acid and platinum were done on a set of 25 patients with lichenoid lesions located on the buccal mucosa, tongue and lips. Application and interpretation of the tests were conducted according to ICDRG (International Contact Dermatitis Research Group). RESULTS: 15 (60 %) patients showed sensitization to 1 or more allergens, with a total of 31 positive reactions. The greatest frequency of positive reactions was to dental metals, with a total of 27 positive reactions. The order of tested metals according to frequency of positive reactions was mercury (6/25/24 %), amalgam (6/25/24 %), nickel (4/25/16 %), palladium (4/25/16 %), cobalt (3/25/12 %), gold (2/25/8 %), chrome (1/25/4 %), indium (1/25/4 %). The clinical relevance of the results with regard to the material's presence in the mouth was demonstrated in 11 (44 %) patients. In 9 patients, replacement of the positively tested materials led to healing or to significant regression of mucosal changes. CONCLUSIONS: The results of the patch tests showed the possible contribution of contact sensitization in the pathogenesis of lichenoid manifestations in the oral cavity. Due to the premalignant character of these lesions, replacement of positively tested materials and follow up of these patients is advised.