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Adhesion of oral bacteria to teeth and restorative materials plays an important role in the pathogenesis of oral diseases. This study investigated the initial adhesion of Streptococcus mutans to enamel and restorative materials. Three types of composites and two types of glass ionomer cements were used. The specimens were coated with freshly collected human parotid saliva. The salivary coated samples were incubated with cell-free glucosyltransferase, and further incubated with sucrose solution. Finally, the specimens were incubated with 3H-thymidine labelled bacteria. Adhesion of the bacteria to the specimens was measured by scintillation counter. SEM observations were performed on each sample. The results showed no significant differences among the materials and the control. These findings can be explained by the pellicle which coated all the specimens. This biofilm, to which the bacteria were adhered and proved to probably masked existing surface properties of the specimens resulting in similar bacterial adhesion.

A detailed morphologic and histologic de-scription of each deciduous and permanent incisor of the rabbit is presented, together with the chronology of their prenatal and postnatal development. The deciduous incisors are teeth of limited growth, but the permanent incisors grow continuously.The rabbit is used frequently in experimental investigations. A review of the literature has shown that the incisors of rabbits have been investigated by a number of observers with different results. The purpose of this investigation was to provide a comprehensive description of the morphology, development, and histology of the incisors of rabbits.Rabbits and hares originally were classified as rodents. But because of differences in the teeth, masticatory movements, and body build, zoologists now do not consider them to be related closely to the rodents; instead, they place them in a distinct order, Lagomorpha.

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A histologic and anatomic investigation of the symphyseal region in rabbits did not reveal a bony fusion between the two halves of the mandible; these two bones are united in the anterior part by a synchrondrosis, and a definite histologic suture with interdigitating bony rugosities and interposed connective tissue, in the posterior part. Functionally, the two parts are immobile and thus constitute one bone.

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A reparative dentin bridge was induced in rat molar teeth by pulp exposure and capping with calcium hydroxide. Transmission electron-microscopic examination after 10 days revealed the presence of odontoblastic cells and collagenous matrix with focal calcifications. The calcifying fronts were composed of hydroxyapatite crystals. Numerous extracellular matrix vesicles were scattered between the forming cells and the calcifying fronts. Some of the vesicles contained electron-dense material and in others, apatite crystals were detected. Matrix vesicles could not be identified in normal, mature calcifying dentin matrix. In view of the present observations and studies on surgical manipulations in articular cartilage, it is concluded that matrix vesicle calcification may result from alterations in the metabolic state of mesenschymal tissues. These changes can be induced surgically or chemically.