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Biomedical subjects

R Hickel

Publications and source records attributed to R Hickel.

At least 109 records · Page 6Linked to original sources
PubMed1989

[Clinical comparison of adhesive systems for bonded bridges].

54 three-unit maxillary anterior bridges with retention meshes were bonded under standardized and, as far as possible, identical clinical conditions using different adhesive systems: Super Bond, a 4-Meta-PMMA resin, and ABC (Adhesive Bridge Cement) and Microfill pontic, both composite adhesives. The restorations were re-evaluated after 5.3 years, at most. Both types of adhesive systems could be tested by contralateral comparison of 10 pairs of bonded bridges. After a mean period of 2.9 years of wear primary failures were observed in 8 out of 54 bonded bridges (approximately 15%). Under the conditions given in this study the failure rates of the composite adhesives and the 4-Meta-PMMA resin were identical after approximately 3 years.

Adolescent↗
PubMed1989

[Indications and materials for fissure sealants].

Due to long-term results with high success rate, pit and fissure sealing is recommended as approved method to prevent caries of pit and fissures. Therefore teeth should be sealed as early as possible--when the tooth can be sufficiently isolated from moisture. The dentist should prefer the approved composite sealers to glass ionomer cements.

Child↗
PubMedDate not supplied

Toxicokinetic of HEMA in guinea pigs.

OBJECTIVE: Unconverted 2-hydroxyethylmethacrylate (HEMA) can be released from dental resin materials and can enter the body in humans. In the present study the uptake, distribution and excretion of 14C-HEMA applied via different routes were examined in vivo in guinea pigs. METHODS: HEMA (0.02 mmol/kg bw labelled with a tracer dose 14C-HEMA 0.3 Bq/g bw) was administered by gastric tube or by subcutaneous injection. Urine, feces, and exhaled carbon dioxide were collected for 24 h after administration. Guinea pigs were killed 24 h after the beginning of the experiment and various organs removed and 14C radioactivity measured. RESULTS: Low fecal 14C levels (about 2% of the dose) and urinary levels of about 15% after 24 h were noted with either route of administration. Direct measurement of exhaled CO(2) showed that about 70% of the dose left the body via the lungs. Two pathways for the metabolism of 14C-HEMA can be described. It is likely that 14C-pyruvate is formed in vivo resulting in the formation of toxic 14C-HEMA intermediates. 14C-HEMA was taken up rapidly from the stomach and small intestine after gastric administration and was widely distributed in the body following administration by each of the routes. CONCLUSIONS: Clearance from most tissues following gastric and intradermal administration was essentially complete within one day. The peak HEMA levels in all tissues examined after 24 h were at least onemillion-fold less than known toxic levels.

Acrylic Resins↗