Biomedical subjects

M Hannig

Publications and source records attributed to M Hannig.

57 records · Page 4Linked to original sources

PubMedDate not supplied

Self-etching primer vs phosphoric acid: an alternative concept for composite-to-enamel bonding.

The purpose of this in vitro study was (1) to investigate the composite-to-enamel bond strength and (2) to analyze the marginal adaptation of resin composite restorations in class 2 cavities using three self-etching priming agents in comparison to conventional phosphoric acid etching and bonding application. In the first part of the study 24 extracted bovine incisors were embedded in acrylic resin and ground flat with 800-grit paper. The following three self-etching priming agents/composite resins were applied to the enamel surfaces of six teeth each: Clearfil Liner Bond 2/Clearfil AP-X (Group I), Etch & Prime 3.0/Degufill mineral (Group II), Resulcin AquaPrime + MonoBond/Ecusit (Group III). In Group IV Ecusit-Mono/Ecusit was used after enamel etching with phosphoric acid (37%). Shear bond strength values measured on a T22 K testing machine at a crosshead speed of 1 mm/min were: 24.2 +/- 3.0 MPa (Group I), 21.9 +/- 1.4 MPa (II), 34.0 +/- 3.6 MPa (III), and 26.3 +/- 1.8 MPa (IV). ANOVA revealed significant (P < 0.05) differences in shear bond strength between groups, except comparison of Group I and II, and Group I and IV. In the second part of the study 24 standardized class 2 cavity preparations with the approximal box extending 1 mm above the CEJ were prepared in extracted human molars. Enamel margins were beveled and the teeth were divided into four groups of six teeth each. Cavities were restored using the self-etching priming agents Clearfil Liner Bond 2 (Group I), Etch & Prime 3.0 (Group II), and Resulcin AquaPrime + MonoBond (Group III). In Group IV composite resin restorations were placed after 37% phosphoric acid etching and bonding application (Ecusit-Mono). Quantitative SEM analysis of the marginal adaptation of the restorations after thermocycling (5-55 degrees C, 2500 cycles) and mechanical loading (100 N, 500,000 cycles) revealed excellent, gap-free margins in 91.2% (Group I), 93.0% (Group II), 92.0% (Group III), and 92.5% (Group IV) of the restorations' approximal area. There were no statistically significant differences between the four groups (P < 0.05). In conclusion, results of the present in vitro study indicate that use of self-etching primers may be an alternative to conventional phosphoric acid pre-treatment in composite-to-enamel bonding restorative techniques.

Acid Etching, Dental↗

PubMedDate not supplied

Comparative in vivo and in vitro investigation of interfacial bond variability.

This comparative in vivo/in vitro study investigated the interfacial adaptation between dentin and composite resins in totally bonded adhesive restorations placed under clinical and laboratory conditions in the same tooth. Cavities were prepared in buccal or lingual surfaces of 47 third-molar teeth scheduled for extraction and randomly assigned for treatment with the following bonding systems/restorative materials: Clearfil Liner Bond 2/Clearfil AP-X (Group I, n = 10), Resulcin AquaPrime + Monobond/MFR Merz (Group II, n = 9), Prime&Bond 2.1/Dyract AP (Group III, n = 9), Scotchbond Multi-Purpose/Z-100 (Group IV, n = 10), and Ecusit Primer AB-Mono/Ecusit (Group V, n = 9). In Group V, a thin layer of a low-viscous compomer (Primaflow) was interposed between the dentin and the composite resin during restoration placement (according to the manufacturer's directions). After extraction a second filling was placed in each tooth with identical materials in the same manner as in vivo. The restoration-dentin interface was evaluated in longitudinally cut sections of the specimens by SEM-analysis, and the frequency of gap formation between restoration and dentin was calculated. Median percentages for the in vivo/in vitro frequency of interfacial gap formation were 29.2%/13.9% in Group I, 33.3%/20.0% in Group II, 40%/5.3% in Group III, 53.9%/30.4% in Group IV and 13.8%/0% in Group V. Comparison of gap formation frequency between fillings placed in vivo and in vitro revealed significant differences (p < 0.05) in Groups II, III and IV. However, in Groups I and V the internal adaptation was not significantly different between in vivo and in vitro applied restorations. A significant (p < 0.01) correlation (Spearman-Rho rank correlation coefficient) was found for the corresponding in vivo and in vitro fillings placed in the individual teeth with regard to interfacial gap formation. It was concluded that achievement of a completely gap-free internal adaptation between restorative material and dentin in totally bonded composite resin restorations is difficult to predict under in vivo as well as in vitro conditions.

Bisphenol A-Glycidyl Methacrylate↗

PubMedDate not supplied

Influence of air-abrasion treatment on the interfacial bond between composite and dentin.

The purpose of this in vitro study was to investigate the effect of air abrasion on the interfacial bond between composite and dentin. Dentin surfaces surrounded by enamel were produced by removing the incisal part of the crown from extracted human anterior teeth. The dentinal area of the specimen surfaces was conditioned either by air-abrasion treatment (27 microns aluminum oxide particles, 120 psi), application of dentin adhesives, and combination of air abrasion and dentin adhesives, or left nontreated (controls). The enamel was conditioned by acid etching, by air abrasion, or by air abrasion and subsequent acid etching. A 2 mm layer of six different composite resins (Brilliant, Charisma, Helioprogress, Herculite, Pekafill, Z-100) was applied on the specimen surfaces and light cured. The composite dentinal interface was evaluated in cross-cut sections of 324 specimens by SEM analysis, and the mean gap width (MGW) between composite and dentin was calculated. SEM analysis revealed gap formation ranging from 1.1-3.6 microns in control specimens. Gap width was reduced significantly due to air-abrasion treatment of the dentinal surface (MGW: 0.3-1.4 microns) or by application of dentin adhesives (MGW: 0.06-0.6 micron). Combined air-abrasion treatment and application of dentin adhesives resulted in a gap-free adaptation between composite and dentin in the majority of specimens. However, thermocycling of the specimens (5 degrees C/55 degrees C; 1000 cycles) caused a significant increase in gap formation (MGW: 0.03-2.9 microns) at the composite-dentin interface. It is concluded that air-abrasion treatment and subsequent application of a dentin adhesive is an effective procedure to resist the contraction stress at the dentinal surface during polymerization of the composite resin and to improve the internal bond of composite resin restorations.

Air↗