Biomedical subjects

E C Munksgaard

Publications and source records attributed to E C Munksgaard.

At least 37 records · Page 2Linked to original sources

PubMed1989

[Retrograde root obturations employing composite and a dentin bonding agent: adaptions of the filling materials and bond strength].

Composite resin containing silver for radiopacity bonds to the dentin surface of a resected and slightly concave root pretreated with a dentin bonding agent (Gluma). The bond strength between composite and apical dentin is about 18 MPa and is not affected by a preceding root canal filling with eugenol-containing sealer. Contamination with saliva or serum of the Gluma-treated dentin surface reduced the bond strength significantly. No reduction in bond strength is observed when the contamination of the surface is performed before Gluma-application. Microscopy of the borderline between composite and dentin as well as SEM of the composite surface adjacent to dentin revealed a good adaptation which presumably does not allow bacterial penetration.

Composite Resins↗

PubMed1989

[Retrograde root canal filling using resin and a dentin bonding agent: analysis of failures].

With Gluma, an aqueous solution of 5% glutaraldehyde and 35% HE-MA, resin may be chemically bonded to a root surface. In the article failures of apical retrograde root fillings with Gluma and resin (retroplast) were studied, clinically and radiographically, as well as by microscopy of ground sections of extracted teeth or by scanning electron microscopy of loosened retroplast fillings. Out of 52 failures, 23 were not related to retroplast (18 had root fracture). Of the remaining 29 cases, 26 were reoperated. More than half of the failures had loose retroplast fillings. The loosening could be caused by: exceeded working time for the resin or moisture, blood or saliva present on the root before filling, debris on the root surface, possibly because of corrosion, or the presence of phenol in the root canal. In five cases of failure there were denuded root canals. Four cases (of 800) with rapidly developing osteitis might have been due to contamination of bone and soft tissue by EDTA, non-polymerized resin, alcohol or glutaraldehyde.

Aldehydes↗

PubMed1989

[Retrograde root canal filling using resin and a dentin bonding agent: operative procedures].

Using a specially designed filled resin and the bonding agent Gluma, the aims were to obtain a thin retrograde filling covering the slightly concave root surface which would close all root canals and avoid excess filling material. To achieve a strong bond, the resin must be applied to an absolutely dry Gluma surface, free of all traces of blood or saliva. Hemostasis was obtained primarily by applying 1% adrenalin and by use of a needle suction tip. Absence of moisture was obtained by removing all soft tissues from the cavity, using dry compressed air and avoiding condensed moisture from a cool resin. To avoid loosening of the filling, the working time of the resin must not be exceeded, and removal of excess filling material must not be done before polymerization is complete. Contamination of the various chemicals and filled resin must be avoided in order to avoid damage to the surrounding tissues.

Aldehydes↗

PubMed1989

[Retrograde root obturations using resin and a dentin bonding agent: a preliminary histologic study of tissue reactions in monkeys].

The histologic response to a new retrograde root filling procedure using composite and a dentin bonding agent (Gluma) was examined in two monkeys (Cercopithecus aethiops). Infected root canals in canines and incisors were retrograde sealed and a histologic examination performed after 1 year. Among three canines, two showed epithelial proliferation on the resected root surface, apparently originating from the incision which had been placed very close to the level of resection. In the third canine, filled with a composite containing tricalciumphosphate, there was not only reformation of new Sharpey's fibers, but also, seen for the first time, regeneration of new cementum directly upon the retrograde filling material (Fig. 1). Two incisors were extracted, the apices resected, a retrofilling applied, and the incisors replanted. In this way any interference by epithelium could be avoided. After 1 year, both teeth showed a narrow fibrous zone without inflammation opposite the filling material (Fig. 2). The surprising finding that a composite could allow complete PDL regeneration including cementum upon the retrograde material implies that a new biologic retrograde root filling principle is at hand. Experiments are now in progress to further characterize the necessary condition for cementum repair upon composite used as a retrograde root filling material.

Animals↗

PubMed1989

[Retrograde root filling utilizing resin and a dentin bonding agent: indication and applications].

With Gluma a methacrylate-based resin may be chemically bonded to dentin with considerable strength. Resin may therefore be used for retrograde root fillings. Whereas a retrograde amalgam filling demands a box-like preparation, retroplast (Gluma and resin) may be applied to a slightly concave root surface. It may therefore be employed in areas normally inaccessible with amalgam technique. Retroplast can thus be used on roots of all molars and to restore root perforations, root resorptions, cracks, grooves and defects of the root. In addition on lateral canals, on extremely thin roots and to cover perforating root canal posts, this technique can also be used. Dentin/root-cement transplantation may be performed for the purpose of reattachment. The article discusses the technique and its applications with examples showing that it may result in satisfactory healing.

Composite Resins↗

PubMed1988

Effect of load-cycling on bond between composite fillings and dentin established by Gluma and various resins.

Cylindrical dentin cavities, pretreated with Gluma and various resins, were filled with Silux, P-30, or Concise. Marginal integrity was in most instances obtained when experimental resins containing propionic aldehyde were used. The bond between composite and dentin established in this way was tested by load-cycling. Cervical located cavities in extracted human teeth, approximately one-half of the margins in dentin, were etched and treated as above. Fillings made of Silux, P-30, or Concise exhibited margins without stain upon axial loading in most cases. The frequency of staining increased when Dycal was used as cavity liner, but were absent in all cases when Concise was used as filling material. The content of propionic aldehyde in the intermediary resin layer may reduce the oxygen tension at the interface and thereby increase the rate of the polymerization at this location.

Acrylic Resins↗

PubMed1988

Bonding of restorative resins to dentine: status of dentine adhesives and impact on cavity design and filling techniques.

In conjunction with the acid etch technique for bonding of restorative resins to enamel, an effective bonding to dentine would eliminate the need for retentive undercuts and ensure a tight marginal seal. Bonding to dentine can be achieved through dentine adhesives. These may be divided into Ca2+-bonding and collagen-bonding types. Several Ca2+-bonding adhesives are based on phosphate methacrylates. Adhesives of this type mediate a bond strength to dentine not exceeding 10 MPa. In contrast, Bowen's bonding system and the Gluma system yield bond strengths higher than 10 MPa. The two latter systems have recently been conceived in simplified versions. In general, the higher the bond strength to dentine mediated by an adhesive, the smaller are the marginal gaps formed by a composite resin polymerizing in a dentine cavity treated by the adhesive. The size and the shape of the cavity influence the width of the marginal gaps. A cavity having a V-shape gives rise to smaller gaps than box-shaped cavities. A filling technique with two 'inclining' layers reduces the width of marginal gaps. Combination of certain Ca2+-bonding and collagen-bonding adhesives results in increased bond strength and smaller marginal gaps.

Adhesives↗

PubMed1987

Dentin-polymer bond established by Gluma and tested by thermal stress.

The walls of cylindrical cavities in human dentin were treated with Gluma and various resins before filling with either a microfilled or a macrofilled composite (Silux, P-30 or Concise). The extent of gaps (crevices) along the tooth/filling interface was observed before and after thermal cycling at restorations polished either 10 min or 24 h after curing of the composite. Application of a resin containing polymerization initiators and 1% propanal before filling with Silux or Concise resulted in restorations without contraction gaps along the tooth/filling interface. When P-30 was used in this procedure, one of six of the fillings exhibited gaps, but none of the six did so when removal of the marginal excess was postponed for 24 h.

Aldehydes↗

PubMed1987

Wall-to-wall polymerization contraction of composite resins versus filler content.

Various amounts of microfiller, condensed microfiller, prepolymer plus microfiller, or macrofiller were added to an unfilled light-curable resin. The marginal adaptation of these experimental resin/filler mixtures was studied by measuring the wall-to-wall polymerization contraction (wtw-contraction) in dentin cavities in vitro. The investigation showed that increasing amounts of microfiller did not affect the wtw-contraction. However, mixtures made by the three other fillers showed a decreasing wtw-contraction with increasing filler concentration.

Bisphenol A-Glycidyl Methacrylate↗

PubMed1987