Werkstoffkundliche Optimierung eines neuen Seitenzahnkomposits - marginale Adaptation und Verschleiß
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Philipps-Universität Marburg
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Abstract
Background and aim of this study
Composites continue to be a technologically elaborated and sensitive dental restora-tion material. Polymerisation shrinkage and insufficient adhesion to the hard tissues of the tooth, especially to dentin, may result in marginal leakage, potentially leading to secondary caries. This shortens the longevity of the restoration.
Therefore the purpose of this in vitro study was to investigate a newly developed com-posite in different combinations with two newly developed and two well-established universal adhesives used in different adhesive techniques. This study evaluated the marginal adaptation and the two-body wear of the fillings before and after thermo-mechanical loading (TML) in the Marburg-type artificial chewing simulator.
Material and methods
64 extracted human molars were prepared with mod-cavities according to a well-established protocol. Mesial the proximal box runs apical of the cementoenamel junc-tion (CEJ), distal it runs coronal of the CEJ. They were divided into eight groups of eight teeth. After being prepared with Xeno Select, EA1, EA2 or Scotchbond Universal in different adhesive techniques, two different composites (EK1/EK2) were applied di-rectly using a simplified layering technique. Before and after TML in the Marburg-type artificial chewing simulator (2.500 thermocycles between 5 and 55°C and 100.000 times 50 N) epoxy resin replicas of the teeth were fabricated. The quality of the filling’s margin was examined by imaging with scanning electron microscope (SEM), whereas the two-body wear depth was measured by imaging with confocal laser scanning mi-croscope (CSLM). The results were analysed with Kruskal-Wallis- and Mann-Whitney-U-Test (p < 0,05).
Results and observations
None of the groups showed a normal distribution of the measured values (Kolmogor-ow-Smirnow test p < 0,05).
In enamel and dentin 100% gap-free margins were measured before TML (p > 0,05). In all groups TML reduced significantly the percentage of gap-free margins in enamel and in dentin (Wilcoxon signed-rank test p < 0,05). In enamel the percentage of gap-free margins after TML was significantly higher in E&R- and SEE-mode (89 - 92%) than in SE-mode (63 - 67%). In dentin the percentage of gap-free margins after TML de-creased to 58 - 66% between the different etching modes without any statistical signifi-cance. Only Scotchbond Universal used in E&R-Mode was significantly worse (57,2%). The new universal adhesives used in E&R- and SE-mode revealed the tendency to a better marginal adaptation (not significant).
The two composites being bonded with the same universal adhesive and adhesive technique showed no difference regarding marginal adaptation.
In all groups the occlusal two-body wear after TML was approximately 40 µm.
Conclusion
Our study points out that after TML for mod-cavities – irrespective of the composite, the universal adhesive or the adhesive technique – no gap-free margins in enamel or den-tin were achievable.
Enamel bonding with universal adhesives was more effective with phosphoric-acid etching than with SE-mode. In dentin different etching modes did not make a significant difference. Hence the universal adhesives work best in SEE-mode. Even with new, advanced products the adhesion to dentin stays the weak spot of adhesive technique. The two new universal adhesives presented a tendency to perform better than the well-established universal adhesives. They were even significantly better than Scotchbond Universal in E&R-mode.
Both the new composites influenced neither the marginal quality nor the occlusal two-body wear.
The occlusal wear was very small and without clinical significance.
Under laboratory conditions the newly developed posterior resin composite in combina-tion with the newly developed universal adhesives showed promising results in regard to marginal integrity in enamel and dentin as well as in regard to two-body wear re-sistance. These results were comparable to well-established products.
After these encouraging in vitro data, clinical trials must show whether these results can also be confirmed under the extreme stress in the oral cavity.
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Dates
Created: 2019Issued: 2019-07-11Updated: 2019-07-11
Faculty
Medizin
Publisher
Philipps-Universität Marburg
Language
ger
Data types
DoctoralThesis
Keywords
marginale AdaptationSeitenzahnkompositeUniversaladhäsiveAdhäsivtechnikVerschleiß
DDC-Numbers
610
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Plagmann, Gisela: Werkstoffkundliche Optimierung eines neuen Seitenzahnkomposits - marginale Adaptation und Verschleiß. : Philipps-Universität Marburg 2019-07-11. DOI: https://doi.org/10.17192/z2019.0336.
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This item has been published with the following license: In Copyright