Antimicrobial efficacy of iodoformized zinc oxide-eugenol sealer on micro-organisms of root canal.

Iodoformized zinc oxide-eugenol was tested for its antibacterial effect against the aerobic and anaerobic bacteria obtained from the root canals of deciduous teeth; the bacteria were staph aureus, strep viridans, strep faecalis, bacteroides melaninogenicus and also mixed culture obtained from infected non-vital anterior teeth. The sensitivity was checked on BHI- agar plates employing well-method. Iodoformized zinc oxide eugenol paste was found to be effective for both the aerobic and anaerobic bacteria of the root canals of deciduous teeth with maximum sustaining period of 10 days; staphylococcus aureus was found to be the most susceptible, while Streptococcus faecalis the most resistant.     

Langerhans cells in oral epithelium of chronically inflamed human gingivae

This study describes the histopathological features and the distribution of oral epithelial Langerhans cells in 19 gingival biopsies originating from an adult Tanzanian population characterized by very poor oral hygiene and severe gingival inflammation. Light-microscopically, all biopsies contained often large inflammatory connective tissue infiltrates, 6 of which predominantly contained plasma cells while the rest were dominated by lymphocytes. Seven specimens contained peculiar accumulations of round lymphoid and dendritic cells in the lower cell layers of the oral epithelium. These phenomena have not previously been demonstrated in human gingiva and deserve further attention in studies on the pathogenesis of periodontal diseases. Immuno-histochemical staining with OKT6, OKT4 and OKT8 antibodies showed markedly increased numbers of OKT6-positive cells in 7 specimens and clusters of OKT4- and OKT8-positive cells in the oral epithelium of 4 specimens. High numbers of OKT6-positive cells were not related to the presence of intra-epithelial, non-keratinocyte infiltrates or large connective tissue infiltrates. The variable numbers of oral epithelial Langerhans cells may therefore result from different bacterial antigens elucidating different responses or, alternatively, reflect different responses to similar plaque antigens penetrating the surface of the oral epithelium.     

Characterization of one phenotype of human periodontal granulation-tissue fibroblasts

Human granulation-tissue fibroblasts were cultured from oral chronic inflammatory lesions and compared with fibroblasts of healthy gingival connective tissue with respect to cell-surface sialoglycoproteins, and the synthesis of extracellular matrix components. Granulation-tissue fibroblasts exhibited a slower growth rate and larger size than their controls. Their cell-surface sialoglycoproteins resembled those of the control cells, except that the relative amount of glycoproteins in the 140-kd region was lower. The ratio of mRNAs for pro alpha l (I) and pro alpha l (III) collagen chains was decreased in granulation-tissue fibroblasts, although electrophoretic fractionation of the proteins did not reveal consistent differences in type I/type III collagen ratio. Granulation-tissue fibroblasts secreted into the culture medium a dermatan sulfate proteoglycan with a lower molecular weight. After digestion with chondroitinase ABC, the molecular weight of the core protein appeared to be identical with that of the control fibroblasts, suggesting a difference in the glycosylation of the core protein. These results support the theory that granulation-tissue fibroblasts represent a distinct phenotype of fibroblastic cells.     

Mobilization of the facial nerve in surgical interventions in the parotid-maxillary area (the topographic anatomical validation)]

A method for facial nerve mobilization is suggested, developed on cranial preparations of adult subjects. The authors have distinguished characteristic topographic and anatomic regularities that are essential in surgery of the mastoid process and parotid-masticatory area for tumor or nontumorous involvement of the parotid gland in case of the facial nerve involvement in the process.     

A six-center international study of treatment outcome in patients with clefts of the lip and palate: Part 5. General discussion and conclusions.

Part 5 is the final part of a series of five articles reporting on an international, multicenter clinical audit of treatment outcome for complete UCLP. A number of recommendations for the methodology of future studies is made especially with respect to entry criteria, sample size, assumptions of homogeneity, and the reproducibility and validity of outcome measures. The findings of the present study regarding clinical procedures are presented tentatively, and improvement and extension of the methodology are required. It appears, however, that acceptable results can be achieved by different programs and ultimately clinical choices may be based on factors such as complexity, costs, and demands of treatment. Standardization, centralization, and the participation of high volume operators were associated with good outcomes, and nonstandardization and the participation of low volume operators with poor outcomes. Therapeutic factors associated with good outcomes were the employment of a vomer flap to close the anterior palate, and poor outcomes with primary bone grafting and with active presurgical orthopedics.     

Marginal breakdown of 5-year-old direct composite inlays

Objectives: The marginal fit of tooth-coloured inlays luted with composite resin luting materials has been considered to be the weak link of the inlays. The marginal breakdown of 5-year-old direct composite resin inlays was evaluated by scanning electron microscopy.

Methods: Replica impressions were made of the occlusal, axial-proximal and accessible cervical-proximal margins of 21 inlays and the marginal quality was quantified.

Results: More than 84% of the total investigated length of the enamel/luting composite agent-luting composite/composite inlay interfaces revealed gap free margins. Proximal margins showed the largest breakdown at the enamel/composite resin interface, while the occlusal margin interfaces showed only a slight difference between the interfaces. The composite inlay and the luting composite resin showed a similar degree of wear in more than 50% of the evaluated marginal length. Medium gap width varied between 60 μm for the occlusal and axial-proximal and 87 μm for the cervical-proximal margins, with a range of 7.6–266 μm.

Conclusion: The direct composite inlays investigated showed good marginal integrity after 5 years in clinical service.     

Caries experience in urban Tanzanian children 1973-84

In 1973 and 1984 the caries status of 624 and 394 children, respectively, was recorded in an urban area of northern Tanzania where the water fluoride content was 2.0-3.5 ppm. Although slightly different scoring criteria were used, the data showed very low levels of caries, and little evidence of increases in caries experience over the 10-yr period. The distribution of caries lesions was markedly skewed, such that a minority of individuals account for most of the caries. The levels of caries were low by international standards and equivalent to those found in children from low fluoride areas of Tanzania.     

Effect of die spacer on the seating of complete cast gold crowns with grooves

Fifty crowns were constructed with an indirect technique for a standardized Ivorine tooth preparation to determine whether casting relief would improve the seating of complete cast crowns with zinc phosphate cement. The variables were two grooves in the preparations and die spacer casting relief of approximately 20 to 40 micron. The tooth preparations of two groups had no grooves, but castings were made with internal relief for only one group. Three groups had buccal and lingual grooves in the preparation. One group had no relief, a second group had complete relief, and a third group had relief but not in the grooves. The discrepancies noted before and after cementation of the castings were measured. The average discrepancy for each group and the significance between groups was determined. Results of this study demonstrated the following. Die relief significantly improved the seating of complete cast-gold crowns with or without grooves. Omitting die spacer from grooves did not reduce the benefits of relieving the remainder of the die. Partial internal relief was better than no relief. The grooves did not disrupt seating when die spacer application was complete or specifically omitted from the grooves alone.