Complications and prognostic considerations in operative dentistry.

Several aspects of routine operative treatment procedures may result in particularly challenging problems and complications. This article reviews the potential for such complications with emphasis on the ultimate treatment prognosis.

Comparison of bone graft materials. Part II. New bone formation with autografts and allografts: a histological evaluation.

The purpose of this study was to make a direct histological comparison of new bone formation evoked by decalcified freeze-dried bone allograft, freeze-dried bone allograft, autogenous osseous coagulum, and autogenous bone blend. Defects were surgically created in the calvaria of 35 guinea pigs. The graft materials were placed in porous nylon chambers and implanted into the defects. Implanted empty nylon chambers served as controls. The animals were sacrificed at 3, 7, 14, 21, 28, 35, and 42 days. New bone formation was determined quantitatively from histologic preparations. It was concluded that, in this model system, decalcified freeze-dried bone allograft is a graft material of high osteogenic potential; autogenous osseous coagulum and bone blend of less potential, and freeze-dried bone allograft even less.

The inhibitory effect of hydrolytic products of starch on in vitro colonization by Streptococcus mutans.

Synthetic culture medium containing potato starch and 1 gm% sucrose, with and without human parotid saliva, were pre-incubated. Filtrates from these mixtures were then incubated with Streptococcus mutans. S. mutans colonization on glass rods was suppressed in the cultures using filtrates from saliva and starch interaction. No inhibition was noted in filtrates pre-treated with parotid saliva in the absence of starch. The results suggest that the hydrolysis of starch by saliva yields by-products which inhibit in vitro S. mutans colonization.

Ultrasonic versus hand filing of dentin: a quantitative study.

Ultrasonic versus hand-powered K type files were compared for their ability to remove dentin from a standardized canal. The ultrasonic energized file removed a significantly greater amount of dentin in a fixed time period.

Human pulpal response to citric acid cavity cleanser.

Treatment of cavities with citric acid cavity cleanser, also used as an etchant, before restoration with zinc oxide-eugenol cement, was toxic to the human dental pulp in comparison to sham-treated controls. The cleanser caused a significantly (P less than .01) greater intensity and incidence (P less than .01) of inflammation. The added insult from cleanser pretreatment caused destruction of the odontoblast processes withnin the cut dentinal tubules, and an increase in diameter of the tubules. These effects on dentin and odontoblasts probably contributed to the observed increase in adverse pulp responses.

Latex spheres as immunologic markers to demonstrate the binding of human salivary immunoglobulins to Streptococcus mutans.

The results of this study indicate that latex beads can be used to identify specific antigen-antibody interactions on the surface of bacterial cells. The application of a Labelling Index allowed specific interactions to be quantitatively distinguished from non-specific latex bead attachments. The labeling indexes for latex beads absorbed to anti-salivary immunoglobulins were significantly higher than for negative control indexes when tested against S mutans treated with saliva. Conversely, there was no significant difference when they were tested against nonoral bacteria treated with saliva. This suggests that both whole and parotid human saliva contained specific antibodies against S mutans.

Parathyroid hormone as a possible causal factor in osteopetrosis of the tl rat.

The possibility of parathyroid dysfunction as a causal factor in the osteopetrosis of the tl rats was explored by evaluating serum calcium (Ca) and immunoreactive parathyroid hormone (iPTH) concentrations in this strain of rats, as compared with those of phenotypically normal littermate (LM) and non-littermate (NLM) control groups. The mean serum Ca concentration in the tl rat was not significantly different from that of the NLM group, although it was less than that of the LM group. However, all Ca values were within the normal range. The mean serum iPTH concentration in the tl rats was not significantly different from those of either control group. The data indicate that the adult tl rat has adequate but not excessive PTH secretion. Therefore, osteopetrosis and its manifestations in the adult tl are not caused by an abnormality of parathyroid function.

Three recessive genes for congenital osteopetrosis in Norway rat.

In the rat, the autosomal recessive toothless (t1) mutation exhibits an acute form of osteopetrosis. This gene is not an allele of either ia or op that causes respectively, a transitory and acute form of the disease. Comparative radiographic study of t1/t1 and op/op mutants reveals some differences in respect to the size and shape of long bones. In contrast to op/op mutants, homozygous t1/t1 animals failed to respond to either parabiosis or bone marrow transplants.

Dental pulp histology observed by scanning electron microscopy.

This article describes the appearance of routine decalcified and paraffin-embedded histologic sections of the human dental pulp as observed with the scanning electron microscope (SEM). The tissue sections were cut at 12 mum in order to increase the three-dimensional effect. The technique was particularly successful in revealing the three-dimensional structure of pulpal blood vessels and nervous tissue. Possible interodontoblastic attachments were revealed at x10,000.