Cariogenic changes in dental enamel of boys and girls in relation to salivary properties. II. Radiological examination.

In earlier clinical studies of a group of children subjected to an intense fluoride treatment programme several salivary properties were related to cariogenic changes in the enamel surface, as assessed by mirror and probe. In this study the relationship between salivary parameters and cariogenic changes was investigated on bitewings taken from the same teeth. Inverse correlations were found between the acid producing capacity of the micro-organisms in the saliva (as determined in the Snyder test) and most cariogenic changes detected in bitewings particularly in boys. These radiologically detected changes in enamel were the reverse of those obtained clinically. These discrepancies were explained by differences in sensitivity between clinical and radiological techniques used to diagnose cariogenic changes. In contrast it was confirmed radiologically that for girls the P concentration in saliva and for boys the amount of resting saliva are important for preventing extension of caries into deeper layers of enamel.

The relation between periodontitis and systemic bone mass in women between 46 and 55 years of age.

It has been suggested that periodontitis and systemic bone mass might be related. In order to evaluate this possible relationship, we performed an intra-oral examination and measured lumbar bone mineral density (lumbar BMD) and metacarpal cortical thickness (MCT) in 286 female volunteers between 46 and 55 years of age. In addition, the alveolar bone height was measured on bite wing radiographs of the dentate subjects. Of the subject, n = 60 (21%) were edentulous. Compared to the dentate subjects, the lumbar BMD and MCT of the edentulous women were not significantly different. In the dentate subjects, no significant correlation was observed between the clinical parameters of periodontitis (mean probing depth, occurrence of bleeding after probing and number of missing teeth) and the bone mass parameters (lumbar BMD and MCT); nor was a significant relation observed between the bone mass measurements and alveolar bone height. We therefore suggest that systemic bone mass is not an important factor in the pathogenesis of periodontitis.

Differences between primary and permanent teeth in posteruptive age dependency of radiological changes in enamel during the development of approximal caries.

A longitudinal radiological study of children (N = 549) who participated in a comprehensive preventive maintenance program showed that caries related events in the approximal surfaces of permanent teeth differed from those in deciduous teeth. Changes in the approximal surfaces of the younger permanent teeth were more pronounced than of the older primary teeth and differed significantly from 1 year to 2.5 years. These findings can be explained by posteruptive maturation of tooth enamel.

[Approximal caries in children]. / Approximale cariës. Een longitudinaal röntgenologisch onderzoek bij kinderen van 4-15 jaar.

A longitudinal radiological study in children (N = 549) who participated in a comprehensive maintenance program (they were treated in the clinic of the Department of Pedodontics of the Academic Centre for Dentistry Amsterdam) suggests that changes in the approximal surfaces of deciduous molars may differ from the changes in the approximal surfaces of permanent (pre)molars. Regression and initiation possibly occur more frequently in the deciduous teeth than in permanent teeth.

Parallelism of implants visualised on the orthopantomogram.

Orthopantomography is often used in implantology to determine the position of implants in the bone. Implants, which in fact are parallel, can be projected in a non-parallel position. Considerations inherent to the technique of orthopantomography are responsible for this phenomenon. In this study some experiments were carried out to demonstrate this. It can be concluded that orthopantomography cannot be used to determine whether implants are placed parallel or not.

Parallelism of hollow-cylinder ITI implants: an experimental study.

Site preparation for oral implants is a delicate surgical procedure. In the ITI F-type and Bonefit implant systems, two cylindrical burs are available. Experiments were performed to verify the clinical experience that the longer bur is more accurate in defining the direction of implants. Several preparations were made in six human femur heads. The purpose of the experiments was to investigate the difference in parallelism between preparations made with the standard cylindrical bur and the bur with the long shaft. The results showed that the bur with the longer shaft was preferred for obtaining an accurate direction and parallelism of the implants.

Digitized image processing and pattern recognition in dental radiographs with emphasis on the interdental bone.

Diagnosis of bone lesions on dental radiographs can be difficult due to the irregular trabecular pattern and subjectivity on the part of the observer. The purpose of this study is to improve the recognition of bone lesions by means of objective computer-aided pattern recognition techniques. This article describes a method for the separation of teeth and bone regions in the image to facilitate further analysis, especially of the interdental bone.

Digitized pattern recognition in the diagnosis of periodontal bone defects.

Radiography is an important tool in the diagnosis of periodontal bone lesions. Due to subjective factors in the interpretation by the observer, however, an error-free diagnosis of bone lesions in an early stage is very difficult. The aim of this study was to reduce the influence of observer subjectivity by means of computer-assisted image processing and pattern recognition in dental radiographs. The findings of the study show that periodontal lesions can be recognized and described in an objective way by means of digitized pattern recognition.