Interactions of fibroblasts with soldered and laser-welded joints.

Relatively little is known about the biocompatibility of the soldered or laser-welded joints of dental appliances. We investigated the reaction of human gingival fibroblasts cultured in vitro in direct contact with samples of soldered and laser-welded joints from orthodontic lingual arches. Contrast phase light microscopy was used to evaluate cell adhesion, morphology and proliferation after 6 and 24h and after 7 and 16 days. Scanning electron microscopy (SEM) was performed at 16 days. Our in vitro findings provide evidence that laser-welded orthodontic appliances have superior fibroblast biocompatibility.

A rapid test for the visual detection of anti-hepatitis C virus antibodies in whole blood.

A rapid test for the visual detection of anti-HCV antibodies in whole blood was evaluated in its accuracy when compared with EIA method. The rapid test was performed blind on 50 HCV EIA-positive (adsorbance greater than 3.0) and on 50 HCV EIA-negative samples. Each whole blood sample was 1:20, 1:50 and 1:100 diluted with saline solution for a total of 400 samples. Results showed a sensitivity of 100% when whole blood was tested, 96% when 1:20 diluted blood was tested, 30% when 1:50 diluted blood was tested and 4% when 1:100 diluted blood was tested. The specificity gave also better results and only one false-positive was found in all samples tested. The test took less than 3 min and only a mechanical pipette was required. In conclusion, the HCV Ab rapid test showed a very high accuracy and could be very useful for the detection of HCV-positive subjects in situations where rapid results are required or technical expertise is limited.

Circulatory dynamics during dental operations in patients with heart transplants.

Twelve patients with heart transplants and who needed dental operations were studied. At the same time, a group of normal subjects was enrolled as control. Blood pressure and heart rate were recorded in all subjects when they sat in the chair, after 5 minutes of relaxation, 5 minutes after administration of local anesthetic, and immediately after each dental extraction or curettage. No statistically significant difference was found between the values recorded during the different situations and the basal values in transplanted patients. Conversely, in the normal subjects, the values recorded when they sat in the chair, at the end of curettage, and at the end of dental extractions were significantly different from the basal values. The slight and dulled cardiovascular reaction to stress in patients with heart transplants suggests that the management of these patients is relatively uncomplicated and certainly easier than treatment of subjects with heart disease.

Pulpal neuropeptidergic fibers.

A study was carried out on Met- and Leu-enkephalin, Gastrin/CCK-, SP-, CGRP-, NPY-immunoreactive fibers using paraffin sections of dental pulp taken from 8 apparently normal teeth (wisdom teeth or teeth extracted for orthodontic reasons). Within the limitations of the samples studied, dental pulp is characterized by the presence of sensory (Enkephalin-, Gastrin/CCK-immunoreactive) and pain fibers (SP-immunoreactive) and of fibers with a potent vasodilatory action (CGRP-immunoreactive) and by the absence of fibers with a vasoconstrictor action (NPY-immunoreactive).

Tranexamic acid as a mouthwash in anticoagulant-treated patients undergoing oral surgery. An alternative method to discontinuing anticoagulant therapy.

A double-blind randomized study was carried out to evaluate the clinical hemostatic effect of tranexamic acid mouthwash after dental extraction in 30 patients who received anticoagulant agents. Surgery was performed with a reduction in the level of anticoagulant therapy in the control group and with no change in the level of anticoagulant therapy in the group who received the tranexamic acid. After the extraction the surgical field was irrigated with a 5% solution of tranexamic acid in the group of 15 patients whose anticoagulant treatment had not been discontinued and with a placebo solution in the group of 15 patients for whom the anticoagulant therapy was reduced. Patients were instructed to rinse their mouths with 10 ml of the assigned solution for 2 minutes four times a day for 7 days. There was no significant difference between the two treatment groups in the bleeding incidence after oral surgery. We conclude that the anticoagulant treatment does not need to be withdrawn before oral surgery provided that local antifibrinolytic therapy is instituted.

[Pain induced changes in circulatory dynamics]. / Modificazioni della dinamica circolatoria indotte dal dolore.

In the present research data about cardiovascular changes induced by pain during a dental extraction are shown. A painful dental extraction causes blood pressure and heart rate changes significantly higher with respect to a painless dental extraction.

[Oral hygiene in Italy]. / Oralhygiene in Italien.

In Italy (58 million inhabitants) over the last 15 years a decrease in caries incidence could be observed: Children (6-10 years old) 1970: 84.5%, DMF-T 4.77; 1980-85: 72%, DMF-T 3.64). Per capita sugar consumption went down from 32.0 kg in 1974 to 28.2 kg in 1983. 30.770 dentists are in practice--incl. medical doctors, who are allowed to practise dentistry--, 8600 of them are members of the Italian Dental Association AMDI. AMDI together with Mentadent Gibbs organised the "Month of Mouth Prevention" in 1988, 4,400 dentists with 305,552 patients joined the programme. Thanks to this programme many data about oral hygiene in Italy have emerged: frequency of brushing, kind and choice of toothbrush, use of toothbrushes (38.5 mio sold in 1988) etc. In Italy water fluoridation ist not practised, in some areas NaF pills have been used.

A new approach to quantify cardiovascular response in dentistry.

Essential hypertension, which is common in dentists, has been attributed to mental stress but the importance of working conditions has not been evaluated. The pressor and forearm circulatory response to correct and incorrect working position during dental practice has been evaluated in 10 normotensive dentists and compared with the effects of mental stress. Mental stress elicited a significant increase in blood pressure not observed during correct dental practice despite a comparable forearm vasodilatation during both tests. Conversely incorrect working position, significantly raised blood pressure to an extent comparable to what observed during mental stress but with only a transitory and rapidly abolished forearm vasodilatation. The recordings of blood pressure or peripheral hemodynamic changes per se did not allow to discriminate between a specific response to mental stress and dental practice which, were clearly differentiated by the analysis of combined pressor and hemodynamic measurements. We conclude that odontoiatric practice carried out in an incorrect working position is able to elicit either an increase in blood pressure or abnormalities in peripheral vascular response which may contribute to the high occurrence of systemic hypertension in dentists. The evaluation of peripheral hemodynamic profile during working conditions seems to provide a useful method for a better understanding of the pattern of cardiovascular involvement in dentistry.

Ultrastructural changes of collagen and elastin in human gingiva during orthodontic tooth movement.

After 15 days of mesializing or distalizing orthodontic treatment, 10 permanent premolars of young patients were extracted with the interdental gingiva. The connective tissues of the compressed or stretched interdental papillae were compared to that of untreated samples by light and transmission electron microscope. Large collagen fibres bundles represented by fibrils with a banding pattern of 64 nm and a mean diameter of 75 nm were observed in compressed interdental gingiva. Several elastic fibres with a mean diameter of 950 nm were also present. In some central areas of compressed gingiva collagen fibrils longitudinally split into widely spaced microfibrils were often observed in proximity to the elastic fibres. In stretched and untreated interdental papillae the collagen fibrils presented a mean diameter of 66 nm and 57 nm respectively. In both groups, few elastic fibres ranging in diameter 600 nm were seen. The increased size of the gingival collagen fibrils undergoing pressure and tension is indicative of remodelling of the fibrous collagen system. The fair increase in number and size of elastic fibres in compressed gingiva suggests that the elastic fibre system takes over the place whenever a collapse of the collagenous framework occurs.