Application and validation of a three-dimensional mathematical model of the human masticatory system in vivo.

A previously described three-dimensional mathematical model of the human masticatory system, predicting maximum possible bite forces in all directions and the recruitment patterns of the masticatory muscles necessary to generate these forces, was validated in in vivo experiments. The morphological input parameters to the model for individual subjects were collected using MRI scanning of the jaw system. Experimental measurements included recording of maximum voluntary bite force (magnitude and direction) and surface EMG from the temporalis and masseter muscles.

Application of digital image analysis in dental radiography for the description of periapical bone lesions: a preliminary study.

This paper describes an application of digital image analysis for the description of periapical bone lesion in dental radiography. These techniques enable the problem of observer variability to be circumvented, and can eventually be used for the quantitative assessment of bone lesions. Since periapical bone lesions appear radiographically as dark areas compared with their surrounding tissues, an edge-detection method was developed to extract the boundaries between anatomy and pathology.

Computer-assisted estimation of lines of action of human masticatory muscles reconstructed in vivo by means of magnetic resonance imaging of parallel sections.

The orientation of these lines of action was estimated in 9 healthy subjects, by reconstructing the muscle shape from a series of parallel sections obtained by MRI. In order to gain insight into sources of error, the lines of action of the masseter and medial pterygoid were estimated from two mutually perpendicular series of sectional images. Average results were compared with anatomical data from the literature.

Bacterial involvement in denture-induced stomatitis.

Denture and mucosal plaque samples were collected from eight full-denture wearers of whom four suffered from denture-induced stomatitis (DIS). Cultures were made, and a proportional identification to species level was carried out of bacteria and yeasts. An inventory was made of the predominant flora.

Cross-inhibition between black-pigmented Bacteroides species.

Cross-inhibition within the group of black-pigmented Bacteroides, including both oral and non-oral strains, was studied by means of a membrane filter technique. It was found that B. gingivalis possessed the most extended inhibitory capacity among all species tested.