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Biomedical subjects

K J Nordenvall

Publications and source records attributed to K J Nordenvall.

At least 19 recordsLinked to original sources
PubMed1992

Glass ionomer cement used as surgical dressing after radical surgical exposure of impacted teeth.

GPA cement was tested as an alternative to conventional surgical dressings in connection with radical surgical exposure of teeth. The material comprised 29 patients (mean age 14 4/12 years) with 35 impacted maxillary canines in palatinal position. Soft tissue and bone covering one fifth to one quarter of the tooth crown were removed. The enamel was cleaned with physiological saline and dried with gauze pads. Ketac-Fil was applied using the ESPE Aplicap system. Application stopped when the level of intact mucosa was reached. At control after 1-2 weeks (35 teeth) all packs were in place. Healing conditions were normal and soft tissue regrowth was not seen. At control after 1-6 months (23 teeth) 10 dressings were in place. Surrounding mucosa was healthy regardless of the presence of absence of pack. Soft tissue regrowth was not seen. 6-16 months postoperatively (12 teeth) all packs except 1 had been lost. Soft tissue regrowth in combination with eruption failure was seen in 2 patients. In these cases the packs had been lost soon after the first control, i.e. before healing had been completed. The results indicate that GPA cement can be recommended as an alternative to conventional surgical dressings in connection with radical surgical exposure of teeth.

Adolescent↗
PubMed1984

The initial gap around large composite restorations in vitro: the effect of etching enamel walls.

Composite resin restorations in cavities are generally associated with the development of a contraction gap during the first minutes after insertion. Enamel-Bond-Concise composite restoration were placed on both approximal sides of extracted pre-molars. The cervical walls of all cavities extended beyond the enamel-cement junction. The enamel walls of one of the cavities in each tooth were acid-etched. The contraction gap was kept air-filled and open at the margin through the use of a special technique. Enamel Bond resin with a fluorescent additive was applied to occlusal and cervical margins of the restorations. The fluorescent resin was "passively" drawn into the gap. In unetched cavities, resin penetrated both cervical and occlusal gaps and some areas of the gap at the axial wall. In cavities with etched enamel, the penetration occurred only at the cervical wall. The distance of penetration from the cervical margin varied from 1 to 6.5 mm, and the width of the contraction gap filled with the fluorescent resin varied from 3.5 to 16 micron. Comparison of the width of the gap at the cervical wall in etched and unetched cavities suggested larger gaps for etched cavities. The method used offers a new technique for the measurement of the contraction gaps around composite resin restorations.

Acid Etching, Dental↗
PubMed1984

Enamel hypoplasia in permanent teeth induced by periodontal ligament anesthesia of primary teeth.

Periodontal ligament anesthesia was applied to 16 primary teeth in jaw quadrants of two monkeys. The teeth in the contralateral positions were not injected and the permanent teeth in this area served as controls. The animals were killed after 22 months when the permanent incisors began to erupt. In total, enamel hypoplasia or hypomineralization (or both) was noticed in 15 permanent teeth in the experimental quadrants but in none of the controls. The results strongly emphasized that periodontal ligament anesthesia should be used with great care on primary teeth close to developing permanent teeth.

Anesthesia, Dental↗
PubMed1983

Protective effect of polystyrene liners for composite resin restorations.

The main purpose of lining cavities before insertion of composite resin restorations is to prevent bacterial contamination at the cavity walls. A thin film of polystyrene liner dissolved in ethyl acetate applied to all surfaces by compressed air provided good protection against bacteria on cavity walls under composite resin restorations. An antibacterial primer in an alcohol solution applied prior to the liner may improve this protection. This procedure had no detectable injurious effect on the pulp.

Animals↗
PubMed1982

Etching of young permanent teeth with an acid gel.

The effect of 15 seconds of etching of young permanent teeth in vitro with a phosphoric acid gel (50 percent) was evaluated with the scanning electron microscope (SEM). Resin impressions of forty-seven pairs of contralateral enamel surfaces divided into three experimental series were studied. A scale with scores from 0 to 3 was used to evaluate the degree of surface irregularity. In the first series the effect of acid gel was compared with the effect of a phosphoric acid solution (37 percent). In the second series 15- and 60-second periods of etching with acid gel were compared. In the third series 15 seconds of acid gel etching of enamel surfaces pretreated with fluoride was compared with the effect of the same etching time on nonfluoridated enamel. It was found that there is no difference in the degree of surface irregularity after etching with an acid solution as compared with an acid gel and that it is possible to create good retentive conditions on the enamel of young permanent teeth after 15 seconds of etching. It was also concluded that extra etching time is not necessary when teeth have been pretreated with fluoride.

Acid Etching, Dental↗
PubMed1982

Dentin sensitivity, odontoblasts and nerves under desiccated or infected experimental cavities. A clinical, light microscopic and ultrastructural investigation.

Cavities were prepared in 35 pairs of young human premolars. One tooth in each pair served as a control. In one Series the test cavity was desiccated with compressed air for one minute. LM and TEM examination of the dentin and the adjacent pulp revealed an extensive aspiration of odontoblasts. Nerve fibers had moved 0.1 to 0.2 mm outward in the tubules. It is suggested that a streching or disruption of the nerve had occurred during desiccation. In a second Series, the test cavity was infected for 1 to 2 weeks. No nerve fibers were seen in the dentinal tubules under the cavities, only cellular remnants and some microorganisms. Despite the absence of nerves the dentin in the bottom of the infected cavities was highly sensitive to stimulation. It was concluded that the nociceptive nerves present in the adjacent inflamed pulp may be terminals, mechanosensitive in nature and that they activated by rapid outward movements of the tubules fluid.

Dental Pulp↗
PubMed1982

Pulpal reaction and microorganisms under Clearfil Composite Resin in deep cavities with acid etched dentin.

Experimental buccal cavities were prepared on 31 pairs of contralateral human premolars. Both cavities were acid etched with 40% phosphoric acid for 15 seconds. The layer of etched enamel was removed from one of the cavities (test) in order to create conditions for microbial invasion to the presumed gap between the resin and dentin. Both cavities were filled with Clearfil Composite Resin after the application of Clearfil Bonding Agent. In the control cavity, the outer portion of the filling was removed and replaced with IRM cement in order to prevent microbial invasion. The teeth were extracted after 1 to 11 weeks. The presence of bacteria and pulpal reactions were studied using routine histological techniques. In several cases the inner resin surface analogous to the cavity floor was studied in the SEM. Bacterial growth was present on the dentinal walls as well as in some of the dentinal tubules in 24 of the 31 test cavities. The underlying pulpal areas showed signs of inflammation. Bacterial growth and pulpal inflammation were absent in 17 control cavities in spite of pulpal lesion or near lesion in 5 of the cavities. In 9 control cavities bacteria and pulpal inflammation were present. This suggests bacterial contamination and/or microbial invasion in spite of the IRM filling. The results show that Clearfil Bonding Agent in combination with Clearfil Composite Resin do not bind sufficiently to etched dentin in cavities to prevent the generation of a gap between the filling and dentinal wall. As a result infection can be established. The results also support the authors' earlier findings that neither acid etching of dentin for 15 seconds nor the chemical properties of resin materials have any especially injurious effect on the pulp, even in deep cavities.

Acid Etching, Dental↗
PubMed1980

Etching of deciduous teeth and young and old permanent teeth. A comparison between 15 and 60 seconds of etching.

A comparison was made between the effects of 15 and 60 seconds of etching with a 37 percent phosphoric acid solution on enamel surfaces from deciduous and young and old permanent teeth. Resin impressions of fifteen pairs of enamel surfaces from each group of teeth were studied in the scanning electron microscope. The results were based on in-pair evaluations. A scale from 0 to 3 was used to evaluate the degree of surface irregularity. For deciduous teeth, no difference was found in effect between the etching periods studied. For young permanent teeth, 15 seconds of etching created more retentive conditions than 60 seconds. For old permanent teeth, the reverse was found. The most retentive conditions were found for the deciduous teeth, regardless of etching time.

Acid Etching, Dental↗
PubMed1980

In vivo resin impregnation of dentinal tubules.

This study investigated the in vivo resin impregnation of dentinal tubules on exposed dentin surfaces with transversely cut tubules and examined the effect of different pretreatment on impregnation of the dentin. The results have lead to the following conclusions: 1. There is no sound reason to routinely etch and impregnate the dentin with resin on cavity walls. 2. It is possible to impregnate flat areas of exposed dentin which are not close to the pulp and which have transversely sectioned dentinal tubules. This may block dentin sensitivity, preventing infection and irritation of the pulp. 3. The etching time with 37% phosphoric acid should be limited to 5 seconds. This is sufficient to open and enlarge the dentinal tubules at the surface. 4. The desiccation should be performed with the air nozzle near, and almost parallel to, a flat surface for at least 15 seconds. An uneven surface results in uneven impregnation of the dentinal tubules due to incomplete desiccation. Therefore, the compressed air should be applied from different directions. Better results are obtained if the dentin surface is smooth. This may be achieved by planing with a smooth fissure bur. 5. To obtain satisfactory desiccation of dentin walls in cavities, an air nozzle should be reduced in diameter enough to allow it to enter the cavity. It should be kept in motion while continuously air drying the cavity surface.

Acid Etching, Dental↗
PubMed1980

The effect of EDTA-containing surface-active solutions on the morphology of prepared dentin: an in vivo study.

The capacities of EDTA-containing and surface-active antibacterial solutions and their combinations for removing amorphous smear layers produced by cutting of dentin were studied in vivo on 132 human dentin surfaces ground at high speed with a diamond point. A combination of 0.2% EDTA and surface-active antibacterial solutions removed most of the smear layers without opening too many tubule apertures or removing peritubular dentin. No difference was found between the cleaning capacity on surfaces ground under water cooling compared to air cooling.

Adolescent↗
PubMed1980

Impregnation of ground, acid etched dentin in vivo, using five commercial resins.

Resin impregnation of dentin was studied in vivo in 64 pairs of contralateral dentin surfaces. One of the surfaces in each pair was randomly selected to be impregnated with Concise Enamel Bond, the other with one of four commercial resins; namely Concise White Sealant, Clearfil Bonding Agent, Estilux Glaze and Uvio Seal. Before impregnation, the dentin surface was ground flat with a flat fissure bur, etched for 5 seconds with Concise Etching Liquid and compressed air desiccated for 15 seconds holding the compressed air near and parallel to the surface. A bulk of composite material was added to facilitate lateral removal of the resin. Enamel and peritubular dentin were removed with acid after extraction to enable the separation of the resin from the softened dentin. A withinpair analysis of the inner resin surfaces was conducted, based on micrographs taken in the scanning electron microscope (SEM). A good and equivalent impregnation of the dentinal tubules was obtained with all the materials except Uvio Seal. Inadequate or no impregnation at all occurred only in areas near the pulp or close to the DE-junction. Short tags, often with concave endings, were constantly obtained with Uvio Seal.

Acid Etching, Dental↗
PubMed1979

Bacteria and pulpal reactions under silicate cement restorations.

Silicate cement was inserted in deep unlined cavities in 70 human teeth; 35 cavities were cleaned with an antibacterial cleanser, and the other 35 cavities in the contralateral teeth were treated with water spray only. In all teeth, invasion of bacteria from the tooth surface was prevented with a surface seal. Histologic examinations after 4 weeks revealed bacterial growth on dentinal walls in 9 of the uncleaned and in 2 cleaned cavities. Only in these 11 teeth was an inflammatory reaction seen in the pulp. Under eight cavities without bacterial growth and with silicate cement placed directly on an exposed pulp, no serious injury and no inflammatory reactions were observed. It was concluded that silicate cement per se does not seriously irritate the pulp. Infection of cavity walls should be avoided, not only by removing grinding debris and antibacterial cleansing, but also by use of a liner to prevent invasion of bacteria from the surface of the tooth.

Anti-Bacterial Agents↗