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Biomedical subjects

T Derand

Publications and source records attributed to T Derand.

12 recordsLinked to original sources
PubMed1996

Profile of work-related health complaints among Swedish dental laboratory technicians.

The purpose of the present investigation was to assess the prevalence and nature of occupation-related health problems among Swedish dental laboratory technicians. A 4-page questionnaire listing seven groups of health complaints was completed by 489 male and 242 female technicians, representing 56% of the active members of their organization. Similar information from 163 males and 160 females with other occupations was used for comparison. The biannual prevalence of health problems among the technicians was 79%, comprising musculoskeletal (68%), dermal (34%), respiratory 31%, neurological (26%), systemic (19%) and eyesight/hearing problems (15%). Job-specific ergonomic and stress factors were responsible for musculoskeletal and neurological (finger) reactions whereas chemical insults, grinding dusts and indoor climate caused dermal, respiratory and systemic reactions. There was no age prevalence as regards health complaints, but female technicians consistently showed a large prevalence of musculoskeletal, dermal systemic and neurological complaints than their male counterparts (P < 0.05, chi2). A similar sex difference was also present in the control group. A considerable part of the reactions were perceived to be of minor importance, bringing the total biannual prevalence down to 57%. However, the prevalence of job-related health complaints was still higher among the technicians than in control groups for all indicators except systemic and eyesight/hearing problems. The profile of health complaints among dental laboratory technicians was characterized by musculoskeletal, neurological and dermal reaction, underlining the importance of job-specific ergonomic and chemical hazards. Only a few of the technicians had consulted medical personnel.

Adult↗
PubMed1995

Fracture toughness and flexural strength of dental ceramics for titanium.

Three brands of dental ceramics for veneering to titanium: TitanBond (O'Hara), Ti-Ceram (Ducera) and Titankeramik (Vita) were tested to compare their fracture properties in wet and in dry conditions. Eight polished and precracked specimens of each material were stored in water at 37 degrees C for 28 d and then preloaded in a four-point bending jig with a constant load of 50 N for 24 h under water. Five of the specimens were fractured by a four-point bending test also under water at 37 degrees C. Crack depths were measured in three different positions in each of the remaining three specimens. Fracture load and crack depths were used to calculate the fracture toughness. Another ten polished specimens were used to measure the flexural strength with a four-point bending test after storage in water at 37 degrees C for 28 d. Equal procedures and numbers of specimens were used to measure fracture toughness and flexural strength without preloading and storage in water.

Analysis of Variance↗
PubMed1994

Effect of selenium on mercury vapour released from dental amalgams: an in vitro study.

Wet corroded and air oxidized surfaces from different types of dental amalgams were used in this in vitro study. The mercury vapour released before and after standardized brushing with a conventional (ACTA) and an experimental selenium-containing toothpaste was examined. The results showed differences between the wet corroded and the air oxidized surfaces. High copper, non- gamma 2- amalgams, released more mercury vapour than the conventional one throughout the experiment. When the amalgam surfaces were brushed with the conventional toothpaste, an increase of the released vapour was noted. The use of the selenium containing toothpaste resulted in all cases, in significantly lower amounts of mercury vapour.

Analysis of Variance↗
PubMed1990

A lining system for composite resin fillings.

Microleakage at the margins is a major problem with composite resin fillings. This study was performed to determine whether a liner that expands on contact with water could prevent leakage. A microfilled composite resin that has a high rate of contraction (taking place while curing) was used in class V cavities of extracted teeth. An experimental liner containing aluminosilicate crystals was painted on the dentin walls before insertion of the filling material. The specimens were thermocycled and sectioned. Class V fillings were also placed in the teeth of beagles. The teeth were extracted after 14 weeks. The depth to which the dye penetrated was measured microscopically. Results showed that the expanding liner almost completely prevented penetration of the dye in both in vitro and animal experiments.

Adolescent↗
PubMed1986

Test of long-term corrosion of dental amalgams.

Seven non-gamma 2-amalgams and one conventional amalgam were used in the study. Cylindrical specimens were kept in a test solution for 1 yr. The depth of corrosion was measured and leakage of copper, zinc and mercury was determined by atomic absorption spectrophotometry. EDX was used to analyze the corrosion products. The results showed that copper leakage from the non-gamma 2-amalgams was higher than from the conventional amalgam. The amount of copper in the solution was not related to the concentration in the alloy. Dissolution of this ion was low during the last 6 months of the experimental period. Mercury leakage was comparatively low for all tested amalgams but the rate seemed to be less time dependent and leakage probably had not stopped after 1 yr. The depth of corrosion in the amalgams was in the range 100-500 micron. Under the experimental conditions the non-gamma 2-amalgams were more corroded than the conventional amalgam.

Chemical Phenomena↗
PubMed1981

Development of artificial carious lesions in enamel after F-varnish (Duraphat) and F-Fe-Al-solution treatment.

An acidified gel system was used to study the development of initial enamel lesions using a test solution containing fluoride in combination with iron and aluminium ions compared to a fluoride varnish (Duraphat). The experiments were performed on both permanent and deciduous teeth. The results showed that the fluoride varnish was superior in retarding the development of initial enamel lesions compared to the test solution. The expected positive effect of trace elements in combination with fluorine could be demonstrated in this experiment. Deciduous enamel showed less acid resistance than permanent enamel under similar experimental conditions.

Aluminum↗