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Biomedical subjects

B Hugo

Publications and source records attributed to B Hugo.

29 records · Page 2Linked to original sources

[The preparation of enamel margin beveling in proximal cavities].

Minicavities for posterior composite resin restorations were prepared in 24 caries-free teeth. The aim of this in vitro study was to evaluate the micromorphology of the proximal cavosurface bevel. The cavosurface bevel has been employed for many years as an accepted modification for composite restorations in permanent anterior teeth. The bevel provides more exposed enamel rod ends available for bonding. Using the acid-etch technique the resin-enamel bond is stronger with etched transverse sections of enamel prisms than with longitudinal sections. Enamel in the proximal and gingival wall of class II cavity preparations for restoration with composite should be beveled because prism direction is at right angles to the surface. The aim of this study was therefore to compare two methods for beveling the box margins of small proximal cavity preparations. One method for the preparation of the proximal bevel was the use of a modified EVA-System with the total amplitude reduced to 0.4 mm, the fixation of the file position and a new developed file (Bevelshape, grain 40 microns). The form of this file was modified in order to produce a short cavosurface bevel of the gingival and proximal wall without danger of damaging the adjacent tooth. The other method was the use of an axial margin trimmer. The micromorphology of the two methods was investigated by means of scanning electron microscopy and a score system as described earlier (Lussi et al. 1987). Statistical analysis revealed significant differences between the two groups. As compared to the axial margin trimmer the new device allowed a significant better finishing of the proximal bevel (p < or = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Dental Caries↗

[The status of the dentition in 2 Swiss population groups before the introduction of refined sugar].

Caries and parodontitis have been one of the most spread diseases of mankind. In an archaeological study, 53 graves of Bernese patricians were exhumed. 22 skulls of adults with 392 teeth were examined. They lived between the 16th and the 18th century in the community of Worb BE. In some cases identification could be accomplished by comparison of oil paintings with skulls, using a computerized technique. The aim of this study was to evaluate the prevalence of caries, the loss of periodontal bone, the amount of calculus and of abrasion. To compare the dental situation with another population segment sex- and age-matched dates were used. This second population segment lived between the 12th and 18th century and belonged to a lower social class than the patricians from Worb. The comparison of these two groups showed significant differences only in the abrasion pattern. We conclude that the social class did not significantly influence most of the parameters studied here. The different abrasion pattern could be due to different dietary habits.

Alveolar Bone Loss↗

Simultaneous dislocation of all five carpometacarpal joints.

A case of unique combination of simultaneous dislocation of all five carpometacarpal joints is presented. The mechanism of injury in this case seems to be some manner of punching with a closed fist rather than direct violence. Satisfactory results were achieved using simple principles of manipulation under anesthesia, open reduction, and skeletal fixation, followed by intensive physiotherapy.

Accidents, Traffic↗

The distally based split soleus muscle flap.

A refinement of the previously described distally based soleus muscle flap is proposed. The essential features of the flap are mobilisation of the tibial origin, splitting the muscle longitudinally, partially along a distinct anatomical plane, and preservation of anatomical continuity of the muscle. We suggest that improved blood supply to this flap derives from the intact major lateral proximal pedicles via the intact lateral portion into the flap. We also think that minimal damage to intramuscular vasculature integrity contributes to the improved circulation. The flap has been designed and studied using ten fresh cadaver leg dissections. Angiographic studies proved adequate blood supply to the flap. The flap has been tested eight times on seven patients with favourable results.

Adult↗

Platelet density analysis: a tool for the detection of acquired storage pool disease in man.

This study was designed to evaluate the usefulness of platelet density analysis in the detection of acquired storage pool defects in human patients. Two groups of patients were investigated: 19 subjects affected with a myeloproliferative disorder (group I) where abnormal platelets are released from the megakaryocytes and 11 patients hospitalized in an intensive care unit (Group II) where normal platelets are injured in the circulation. Platelet density distribution after isopycnic centrifugation on a discontinuous stractan density gradient, dense granule markers (serotonin, ATP and ADP) and alpha granule markers (intraplatelet beta-thromboglobulin and platelet factor 4) were simultaneously determined. An increased proportion of the percentage of light platelets was observed in 16 patients of group I and nine of group II; an increased ATP/ADP ratio was observed in 12 patients of group I and 10 of group II. Both the tests were abnormal in 11 patients of group I and nine of group II. In group I, the level of serotonin was low and was related to the percentage of light platelets. The alpha granule specific proteins were normal in the two groups. These results indicate that platelet density analysis may serve as a screening test to detect exhausted platelets in human diseases.

Adenosine Diphosphate↗

Guidance of shrinkage vectors vs irradiation at reduced intensity for improving marginal seal of class V resin-based composite restorations in vitro.

This study evaluated the influence of radiation intensity on polymerization of a resin-based composite (RBC) and compared the influence of guidance of shrinkage vectors vs irradiation at reduced light intensity on the marginal seal of Class V RBC restorations in vitro. The degree of cure was studied indirectly by measuring the Vickers hardness (1.96 N, 30 seconds) at the bottom of disc-shaped specimens 2 mm in height at different periods of time after light irradiation. After one hour, irradiation using a high-intensity curing light (Heliolux GTE, Vivadent, 600 mW/cm2) [HICL] from close distance for 20 seconds, 40 seconds or 60 seconds or a low-intensity curing light (Vivalux, 250 mW/cm2) [LICL] from close distance for 60 seconds produced higher hardness values compared to 20 seconds or 40 seconds using the LICL or using the HICL from a distance of 10 mm. After three and 24 hours, higher hardness was observed for all irradiation protocols. After 24 hours, only specimens irradiated by the HICL for 20 seconds or 40 seconds from 10 mm distance featured significantly lower hardness compared to the remaining curing modes. The influence of different irradiation strategies on marginal seal of Class V RBC restorations was evaluated in vitro using dye penetration after water storage (60 days, 37 degrees C) and thermocycling (2500 cycles 5 degrees-55 degrees C). The HICL produced more dye penetration than the LICL. Placing the light tip directly over or 10 mm above the center of the cavity ("standard irradiation, ["distance irradiation"]") resulted in similar penetration values. In contrast, positioning the light tip apical to the cervical margin and moving it slowly to the center of the cavity ("cervical start irradiation") compromised the marginal seal.

Analysis of Variance↗