The effect of direct and alternating electrical currents on the vessel walls of the tooth pulp -- TEM studies.

Devices which operate on the basis of electrical charges are increasingly being used in stomatology, such as in cariology for the detection of invisible caries lesions or for the measurement of canal lengths during patient treatment. The majority of these devices now emit a current of alternating frequency. The aim of the work was to explain how the electrical devices of labile frequency commonly used in stomatology influence the vessels of the tooth pulp. Teeth extracted for orthodontic reasons were investigated with the use of a transmission electron microscope. The teeth were treated with current emitted by a specially constructed device. The control group comprised 4 teeth. No changes were found in the electron microscopic studies in the slides of the teeth treated with low charges of current. However, in the specimen treated with current charges of 9600 microC or more flattened endotheliocytes were found together with exudation in the vessel lumen. Cases are referred to in which the duration of the work was 2 or 3 times longer than normal and in which a current of constant intensity was emitted uninterruptedly.

A comparison of the anatomical structure of odontoblasts and the connective tissue fibres in relation to the age of the patient.

The aim of this work was to study the structure of dental pulp (mainly the connective tissue fibre and odontoblasts) during the active production of dentine in relation to the age of the patient. The pulps of the teeth extracted for orthodontic reasons from a population of 10-50 year-olds were investigated with the help of a transmission electron microscope (TEM) and a scanning electron microscope (SEM). Condensation of the small collagen fibres and fibrils around the morphotic elements of the dental pulp were found more often in the elderly patients.

Reliability and validity issues of laser fluorescence measurements in occlusal caries diagnosis.

OBJECTIVES: Recently, a device for detecting occlusal caries lesions based on laser fluorescence measurements (DIAGNOdent) has been introduced. The reliability (reproducibility) and validity of this laser-fluorescence device were investigated. METHODS: In the in vitro part of the study, 49 permanent molars were measured by two observers using two DIAGNOdent devices. In addition, visual inspection was performed. The teeth were sectioned to measure the actual depth and area of the caries lesions. In the in vivo part of the study, 45 sites at the occlusal surfaces of permanent molar teeth in 13 patients were measured by two observers using two DIAGNOdent devices, manufactured in two successive years. RESULTS: The reliability of both DIAGNOdent devices expressed in the intraclass correlation coefficient (ICC=0.90 for observer 1, and 0.88 for observer 2) was high, and so was the interobserver reliability (ICC=0.85 for the 1998-device, ICC=0.90 for the 1999-device). The correlation between DIAGNOdent measurements and the actual depth of the caries lesions was lower than that of visual inspection by one observer, yet higher than that of a second observer. The specificities of visual inspection (0.94 and 0.88) were higher than those of the DIAGNOdent devices, whereas the sensitivities of the DIAGNOdent devices (0.93-1.00) exceeded those of visual inspection The validity of the DIAGNOdent, expressed as the area under the receiver operating characteristic curve, was not statistically significantly different from that of visual inspection (P>0.05). The DIAGNOdent measurements showed a higher association with the enamel part of the caries lesion than with the dentinal part. CONCLUSIONS: The DIAGNOdent is suitable for monitoring small caries lesions. Because of the high reproducibility of DIAGNOdent devices produced in successive years, a DIAGNOdent device may be replaced by a new one. Due to the higher specificity, visual inspection should be preferred to diagnose occlusal caries lesions in populations with a low caries prevalence.