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Biomedical subjects

E K Hansen

Publications and source records attributed to E K Hansen.

13 recordsLinked to original sources
PubMed1992

Dentin hypersensitivity treated with a fluoride-containing varnish or a light-cured glass-ionomer liner.

Dentin hypersensitivity in 112 teeth was randomly treated with Duraphat or Vitrabond. No patients were included unless they, without being asked, complained about daily pain for a long period of time caused by cold, warm, sweet, sour, touch or any combination of these five variables. Patients were excluded if the dentin hypersensitivity could have been caused by cervical abrasion/erosion lesions deeper than 1 mm, cracked-tooth syndrome, caries lesions, operative caries treatment, and/or periodontal surgery or root scaling within the last 6 months. The pain was registered on a binary scale: 1) pain before the treatment; and 2) pain/no pain after the treatment. With Duraphat, 22% of the treatments failed within 1 wk and the cumulative 1-yr success rate was 41%. With Vitrabond, 2% failed within the first week and the 1-yr success rate was 79%. The difference between the two treatments was highly significant. Patients in whom Duraphat failed were treated with Vitrabond and vice versa; the 1-yr success rate for the retreated teeth was 68% when "Duraphat-failures" were treated with Vitrabond and 42% when "Vitrabond-failures" were treated with Duraphat.

Adult↗
PubMed1992

Five-year study of cervical erosions restored with resin and dentin-bonding agent.

The cumulative retention rate of a microfilled resin in non-undercut cervical abrasion/erosion lesions was studied over a 5-yr period. The enamel was etched and the dentin was pretreated with either Gluma (n = 75) or the first marketed version of Scotchbond (n = 30). The cumulative 5-yr retention rate of the Gluma fillings was 90% and that of the Scotchbond fillings 47% (the 95% confidence limits were 83-98% for Gluma fillings and 27-67% for Scotchbond fillings). The retention rate with both bonding agents was significantly higher in the maxillary arch than in the mandibular arch.

Acid Etching, Dental↗
PubMed1991

Influence of the solubility parameter of intermediary resin on the effectiveness of the gluma bonding system.

The aim of the present study was to investigate the effect of the solubility parameter of the intermediary resin in the Gluma system on the bonding to dentin. The solubility parameter of the resins was varied between 18.8 x 10(3) and 21.1 x 10(3) J(1/2)/m3/2 by varying the composition of the resin. The efficacy of the bonding system was determined by measurements of marginal gaps formed by polymerization contraction of a restorative resin in dentin cavities treated with the bonding system. The bonding system had maximum efficacy at a solubility parameter of the intermediary resin of delta = 20.0 x 10(3) J(1/2)/m3/2. This finding corroborates a concept of bonding to dentin that involves a mechanical interlocking by interpenetrating resins.

Analysis of Variance↗
PubMed1990

Marginal adaptation of resin in relation to application technique and use of a calcium hydroxide liner.

The marginal adaptation of a restorative resin was examined in cone-shaped cavities prepared in extracted human teeth. The use of a thin layer of a Ca(OH)2 liner in the bottom of the cavities did not influence the wall-to-wall (wtw) polymerization contraction and it did not affect the gap-reducing efficacy of a dentin-bonding agent. The wtw contraction was markedly increased when the restorative resin was applied in two layers parallel to the free surface of the cavity; the reason for this is supposed to be that the ratio between the volume of the filling (V) and the area of the cavity wall (A) is increased for the second layer compared to the V/A ratio found in cavities filled with one increment.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1990

In vivo fractures of endodontically treated posterior teeth restored with amalgam.

The cumulative survival rate (retention of both cusps) and the fracture pattern of 1639 endodontically treated posterior teeth were assessed in a retrospective study. All teeth had an MO/DO or an MOD cavity restored with amalgam without cuspal overlays. The 20-year survival rate of teeth with an MO/DO cavity was markedly higher than that of teeth with an MOD cavity. The lowest survival rate was found for the upper premolars with an MOD cavity: 28% of these teeth fractured within 3 years after endodontic therapy, 57% were lost after 10 years, and 73% after 20 years. Generally, the cusp most prone to fracture was the lingual one, and lingual fractures caused significantly more damage to the periodontal tissues than did facial or total crown fractures. The severity of periodontal damage increased with posterior location of the tooth. By far the most serious failures, irrespective of the cavity type, were found for the upper second molar, as 10 of 29 fractures led to extraction. It is concluded that amalgam, especially in MOD cavities, is an unacceptable material for restoration of endodontically treated posterior teeth if used without cuspal overlays.

Analysis of Variance↗
PubMed1990

In vivo fractures of endodontically treated posterior teeth restored with enamel-bonded resin.

The cumulative survival rate of 190 endodontically treated posterior teeth were assessed in a retrospective study; all teeth had an MO/DO or an MOD cavity restored with a composite resin without cuspal overlays after previous acid-etching of the enamel. In contrast to our previous study on endontically treated posterior teeth restored with amalgam, the survival rate of the MOD resin-restored teeth was equal to that of MO/DO teeth. Teeth restored with a light-activated resin had a much lower survival rate than teeth restored with a chemically-activated material, the cause presumably being that the light-activated resins were insufficiently irradiated. Nearly 25% of the teeth had been restored with a microfilled resin for anterior use and these teeth had a lower survival rate than had teeth restored with a macrofilled or hybrid resin. It was also found that a beveling technique did not decrease the fracture rate while the use of an intermediate layer of low-viscosity resin resulted in a significant improvement.

Bicuspid↗
PubMed1978

Effects on muscarinic receptors of various agents in reversal of neuro-muscular blockade: a study evaluating atropine, glycopyrron, neostigmine and pyridostigmine.

The effects were studied of various drug combinations, recommended for use in reversal of neuromuscular blockade, on heart rate and salivary secretions in 80 healthy patients anaesthetized with nitrous oxide-oxygen-halothane and relaxed with d-tubocurarine. The drug combinations were mixtures of atropine 1 mg--neostigmine 2.5 mg, atropine 1 mg--pyridostigmine 15 mg, glycopyrron 0.5 mg--neostigmine 2.5 mg, and glycopyrron 0.5 mg--pyridostigmine 15 mg, respectively. It was found that administration of the atropine-containing mixtures induced more pronounced initial increases and delayed decreases in heart rate than the mixtures containing glycopyrron. Pyridostigmine-containing mixtures elicited a somewhat more pronounced initial increase in heart rate than neostigmine-containing mixtures, but a less pronounced and delayed decrease in heart rate. Supraventricular arrhythmias occurred less frequently in the pyridostigmine groups than in the neostigmine groups. No such difference was found between the atropine and glycopyrron groups. Glycopyrron caused a more intense dryness of the mouth than atropine. A differential attitude towards the use of drugs for reversal of neuromuscular blockade, based on the cardiovascular state of the particular patient, might be recommendable.

Adolescent↗