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Wear resistance of newly developed experimental synthetic hard resins
e52
d e n t a l m a t e r i a l s 3 0 S ( 2 0 1 4 ) e1–e180
using a Brookfield DV-II + Pro viscometer in a cone/plate setup. The data were compared using ANOVA at p < 0.05. Results: The initial polymerization rate (×10−4 (s−1 ) for the hydrophilic-rich phase (16.6 ± 4.7) was significantly lower than the hydrophobic-rich phase (297 ± 25). The hydrophobicrich phase undergoes autoacceleration immediately following exposure to visible light, but the hydrophilic-rich phase exhibits delayed post-polymerization at a much later stage. Model hydrophilic-rich phases with reduced photo-initiator content exhibit limited polymerization, whereas with sufficient photo-initiator content the hydrophilic-rich phases show substantial polymerization, but at a much delayed rate. Conclusion: The photo-initiator composition plays a critical role in the polymerization behavior of the hydrophilicrich phase under conditions that simulate the wet, oral environment. The photoinitiator system in current dentin adhesives should be optimized to promote compatibility with the hydrophilic-rich phase and to provide sufficient polymerization under clinically relevant conditions. Acknowledgement: This investigation was supported by Research Grant: R01DE14392 (PS) and R01 DE022054 (PS, JSL) from the National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892. Keywords: Dentin adhesive; Phase separation; Polymerization kinetics
Table 1 – Wear value of synthetic hard resins for crown and bridge. GRD2-02 Wear value
a
5.0 (1.6)
GRADIA b
20.0 (1.8)
CERAMAGE 78.0 (7.0)c
Same superscript means not significantly different.
and Glycerin was applied to contact area. Data were analyzed by one-way ANOVA (p < 0.01). Results: GRD2-02 showed the lowest wear value in this study, and GRADIA was second only to GRD2-02. Other synthetic hard resins for crown and bridge showed higher wear value (Table 1). Conclusion: These results suggested that GRD2-02 has higher wear resistance than other synthetic hard resins for crown and bridge. Keywords: Synthetic hard resin; Wear resistance http://dx.doi.org/10.1016/j.dental.2014.08.104 104 Examinations with PEEK-polymer as a telescopic-crown material N. Holzer ∗ , H.C. Roggendorf, F.-J. Faber
http://dx.doi.org/10.1016/j.dental.2014.08.103 103 Wear resistance of newly developed experimental synthetic hard resins T. Shoji ∗ , D. Machida, T. Kumagai Research and Development Department, GC Corporation, Tokyo, Japan Purpose: GRADIA (GC) is an advanced ‘MFR composite’. Its internal structure consists of reinforced bonds between an organic/inorganic filler and a lightly filled matrix resin which together impart a very high mechanical strength whilst being ‘gentle’ on opposing teeth. G-aenial Universal Flo (GUF, GC) was developed under a unique concept called injectable composite resin. GUF shows high wear resistance due to highly loaded and homogeneously dispersed nano-filler. This time, a new synthetic hard resin prototype (GRD2-02, GC) with homogeneous nano-filler dispersion technology from GUF was developed. The purpose of this study was to investigate wear resistance, compared with other synthetic hard resins for crown and bridge. Methods and materials: GRD2-02, GRADIA, CERAMAGE (Shofu), nexco (Ivoclar/Viavadent) were examined in this study as synthetic hard resins for crown and bridge. Each material was filled into metal (contact area 2.1 mm diameter) mold in order to make specimens and cured according to the manufacturers’ instructions. All specimens were stored in 37 ◦ C water for 24 h and performed 3-body wear test (n = 4). 3-Body wear test was performed with original wear test machine for 100,000 cycles (load 0.84 MPa). The slurry mixture of PMMA
University of Cologne, School of Dental and Oral Medicine, Cologne, Germany Purpose: The purpose of this in-vitro-study was to evaluate the longterm use of a PEEK-polymer as a telescopic-crown material. Methods and materials: Twenty inner cylindric telescopic crowns were made for four groups: (A) non-preciousalloy [Starloy, Gramm, Ditzingen, Germany], (B) zirconia [cercon, Degudent, Hanau, Germany], (C) pressed PEEKpolymer [BioHPP, Bredent, Senden, Germany] and (D) milled PEEK-Polymer [BioHPP, Bredent, Senden, Germany]. Outer crowns were all made from pressed PEEK-Polymer. Each pair of crowns was adjusted to provide a retentive force of approximately 2.5 N (±1.5 N) and subjected up to 10,000 insertion/separation cycles with a universal testing machine [Zwicki Typ 1120, Zwick/Roell, Ulm, Germany]. In the process retentive forces (RF) of each telescopic crown were measured continuously. All specimens were tested with and without lubrication by distilled water. RF were recorded and statistically analyzed by multiple ANOVA (level of significance: p = 0.05). Results: After the completed artificial aging (10,000 cycles), all specimens demonstrated clinical suitable RF. The RF of all specimens increased within the first 1000 cycles from 3 N (±0.6 N) to 5.5 N (±2.1 N) (Group A), from 3.1 N (±1 N) to 5.9 N (±3 N) (Group B), from 2.5 N (±0.3 N) to 3.4 N (±1.3 N) (Group C) and from 2.2 N (±0.9 N) to 2.5 N (±1.7 N) (Group D). Afterwards Groups C and D remained nearly unchanged. The RF within the Groups A and B showed higher variability from 0.72 to 13.15 N. Conclusion: Within the limitations of this study the tested telescopic crowns showed clinical acceptable retentive properties for all material combinations. The BioHPP patrices with
d e n t a l m a t e r i a l s 3 0 S ( 2 0 1 4 ) e1–e180
using a Brookfield DV-II + Pro viscometer in a cone/plate setup. The data were compared using ANOVA at p < 0.05. Results: The initial polymerization rate (×10−4 (s−1 ) for the hydrophilic-rich phase (16.6 ± 4.7) was significantly lower than the hydrophobic-rich phase (297 ± 25). The hydrophobicrich phase undergoes autoacceleration immediately following exposure to visible light, but the hydrophilic-rich phase exhibits delayed post-polymerization at a much later stage. Model hydrophilic-rich phases with reduced photo-initiator content exhibit limited polymerization, whereas with sufficient photo-initiator content the hydrophilic-rich phases show substantial polymerization, but at a much delayed rate. Conclusion: The photo-initiator composition plays a critical role in the polymerization behavior of the hydrophilicrich phase under conditions that simulate the wet, oral environment. The photoinitiator system in current dentin adhesives should be optimized to promote compatibility with the hydrophilic-rich phase and to provide sufficient polymerization under clinically relevant conditions. Acknowledgement: This investigation was supported by Research Grant: R01DE14392 (PS) and R01 DE022054 (PS, JSL) from the National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892. Keywords: Dentin adhesive; Phase separation; Polymerization kinetics
Table 1 – Wear value of synthetic hard resins for crown and bridge. GRD2-02 Wear value
a
5.0 (1.6)
GRADIA b
20.0 (1.8)
CERAMAGE 78.0 (7.0)c
Same superscript means not significantly different.
and Glycerin was applied to contact area. Data were analyzed by one-way ANOVA (p < 0.01). Results: GRD2-02 showed the lowest wear value in this study, and GRADIA was second only to GRD2-02. Other synthetic hard resins for crown and bridge showed higher wear value (Table 1). Conclusion: These results suggested that GRD2-02 has higher wear resistance than other synthetic hard resins for crown and bridge. Keywords: Synthetic hard resin; Wear resistance http://dx.doi.org/10.1016/j.dental.2014.08.104 104 Examinations with PEEK-polymer as a telescopic-crown material N. Holzer ∗ , H.C. Roggendorf, F.-J. Faber
http://dx.doi.org/10.1016/j.dental.2014.08.103 103 Wear resistance of newly developed experimental synthetic hard resins T. Shoji ∗ , D. Machida, T. Kumagai Research and Development Department, GC Corporation, Tokyo, Japan Purpose: GRADIA (GC) is an advanced ‘MFR composite’. Its internal structure consists of reinforced bonds between an organic/inorganic filler and a lightly filled matrix resin which together impart a very high mechanical strength whilst being ‘gentle’ on opposing teeth. G-aenial Universal Flo (GUF, GC) was developed under a unique concept called injectable composite resin. GUF shows high wear resistance due to highly loaded and homogeneously dispersed nano-filler. This time, a new synthetic hard resin prototype (GRD2-02, GC) with homogeneous nano-filler dispersion technology from GUF was developed. The purpose of this study was to investigate wear resistance, compared with other synthetic hard resins for crown and bridge. Methods and materials: GRD2-02, GRADIA, CERAMAGE (Shofu), nexco (Ivoclar/Viavadent) were examined in this study as synthetic hard resins for crown and bridge. Each material was filled into metal (contact area 2.1 mm diameter) mold in order to make specimens and cured according to the manufacturers’ instructions. All specimens were stored in 37 ◦ C water for 24 h and performed 3-body wear test (n = 4). 3-Body wear test was performed with original wear test machine for 100,000 cycles (load 0.84 MPa). The slurry mixture of PMMA
University of Cologne, School of Dental and Oral Medicine, Cologne, Germany Purpose: The purpose of this in-vitro-study was to evaluate the longterm use of a PEEK-polymer as a telescopic-crown material. Methods and materials: Twenty inner cylindric telescopic crowns were made for four groups: (A) non-preciousalloy [Starloy, Gramm, Ditzingen, Germany], (B) zirconia [cercon, Degudent, Hanau, Germany], (C) pressed PEEKpolymer [BioHPP, Bredent, Senden, Germany] and (D) milled PEEK-Polymer [BioHPP, Bredent, Senden, Germany]. Outer crowns were all made from pressed PEEK-Polymer. Each pair of crowns was adjusted to provide a retentive force of approximately 2.5 N (±1.5 N) and subjected up to 10,000 insertion/separation cycles with a universal testing machine [Zwicki Typ 1120, Zwick/Roell, Ulm, Germany]. In the process retentive forces (RF) of each telescopic crown were measured continuously. All specimens were tested with and without lubrication by distilled water. RF were recorded and statistically analyzed by multiple ANOVA (level of significance: p = 0.05). Results: After the completed artificial aging (10,000 cycles), all specimens demonstrated clinical suitable RF. The RF of all specimens increased within the first 1000 cycles from 3 N (±0.6 N) to 5.5 N (±2.1 N) (Group A), from 3.1 N (±1 N) to 5.9 N (±3 N) (Group B), from 2.5 N (±0.3 N) to 3.4 N (±1.3 N) (Group C) and from 2.2 N (±0.9 N) to 2.5 N (±1.7 N) (Group D). Afterwards Groups C and D remained nearly unchanged. The RF within the Groups A and B showed higher variability from 0.72 to 13.15 N. Conclusion: Within the limitations of this study the tested telescopic crowns showed clinical acceptable retentive properties for all material combinations. The BioHPP patrices with