Effect of insertion of osseo-integrated prosthesis on the oral microflora

Ten patients undergoing treatment with bridges supported by osseo-integrated oral titanium implants were studied regarding the oral microflora. Saliva samples for microbiological studies were collected before the abutment operation, 1 week after the operation, after the bridges were inserted and again 52 weeks after the abutment operation. The implants did not induce colonization with "plaque streptococci" such as Streptococcus mutans and Streptococcus sanguis. A marked colonization with potentially pathogenic microorganisms such as Staphylococcus aureus, Pseudomonas species and enterobacteria was observed after the abutment operation. This was probably due to the use of surgical dressing.     

Neural pathway involved in the excitation of motoneurones to jaw-opening muscles by stimulation of the orbital cerebral cortex in the cat

The pathway and synaptic basis for the efferent discharge in the digastric nerve evoked by stimulation of the orbital cortex were studied in cats anesthetized with alpha-chloralose. Transection of the brain stem at the boundary between the pons and the medulla oblongata abolished discharge. Intracellular recording from anterior digastric motoneurones revealed that the orbital cortical stimulation evoked excitatory post-synaptic potentials with a latency that was longer by one synaptic delay than that of spike potentials evoked in medial bulbar reticular neurones making a direct excitatory projection to anterior digastric motoneurones. It was concluded that the excitatory effects was mediated by the medial bulbar reticular formation.     

In-vitro cultural parameters and protein and prostaglandin secretion of epithelial cells derived from porcine rests of Malassez.

Cultured epithelial cells (E-cells) derived from the rests of Malassez exhibited a diploid karyotype with a modal number of 38 chromosomes, which is the number reported for the pig. Unlike the cell rests in vivo, which appear to be quiescent, E-cells in culture secreted several proteins. The doubling time of E-cells was 36 h. 80 per cent remained sufficiently viable to attach to the culture dish after extensive trypsinization. Their size distribution was unchanged over 9 subcultures. The E-cells secreted prostaglandins of the E and F series into the culture medium. As prostaglandins have been implicated in bone resorption associated with dental cysts, prostaglandin production by epithelial cells derived from the rests of Malassez may contribute to the mechanism of cyst growth.     

A composite general anesthesia technique using ketamine for pediatric outpatients.

A study of 43 pediatric oral surgery patients was conducted in a clinical environment. The anesthetic regimen of a minimum dose of ketamine hydrochloride, nitrous oxide-oxygen, and a local anesthetic was tested for recovery time and degree of acceptance by parents and patients. With this regimen, the average recovery time from completion of the procedure was 30 minutes. The combination of these drugs provided a rapid, smooth induction, additional time while the ketamine-induced anesthesia was dissipating, no major complications, and good acceptance by parents and patients.     

Inhibitory effects on jaw muscle activity of innocuous and noxious stimulation of facial and intraoral sites in man

Controlled mechanical stimulation of the upper lip in seven subjects resulted in a period of complete or partial inhibition of the electromyographic activity of the masseter muscle. When a painful stimulus was delivered to the lip, a later inhibitory period with a more variable duration was produced. Innocuous stimulation at various intraoral sites led to an early inhibitory period with characteristics similar to those of inhibition produced by innocuous lip stimulation. An increase in stimulus intensity to a noxious level resulted in a second period of inhibition comparable to that produced by noxious lip stimuli. The intensity of the stimulus and the level of muscle activity maintained by the subject were found to influence the incidence and duration of the inhibitory periods. Thus, innocuous and noxious stimulation, whether applied intraorally or extraorally, may result in two distinct periods of inhibition in the jaw-closing muscles. The role in orofacial function of the first inhibitory period has yet to be demonstrated, but the second period is probably involved as a protective reflex.