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Effects of coronal substrates and water storage on the microhardness of a resin cement used for luting ceramic crowns.

Mendonça LM, Pegoraro LF, Lanza MD, Pegoraro TA, Carvalho RM - J Appl Oral Sci (2014 Jul-Aug)

Bottom Line: The success of cementation depends on the achievement of adequate cement curing.Data were first analyzed by three-way ANOVA that did not reveal significant differences between thirds and occlusal surface (p=0.231).The type of material employed for coronal reconstruction of preparations for prosthetic purposes may influence the cement properties.

View Article: PubMed Central - PubMed

Affiliation: Department of Prosthodontics, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.

ABSTRACT

Unlabelled: Composite resin and metallic posts are the materials most employed for reconstruction of teeth presenting partial or total destruction of crowns. Resin-based cements have been widely used for cementation of ceramic crowns. The success of cementation depends on the achievement of adequate cement curing.

Objectives: To evaluate the microhardness of Variolink® II (Ivoclar Vivadent, Schaan, Liechtenstein), used for cementing ceramic crowns onto three different coronal substrate preparations (dentin, metal, and composite resin), after 7 days and 3 months of water storage. The evaluation was performed along the cement line in the cervical, medium and occlusal thirds on the buccal and lingual aspects, and on the occlusal surface.

Material and methods: Thirty molars were distributed in three groups (N=10) according to the type of coronal substrate: Group D- the prepared surfaces were kept in dentin; Groups M (metal) and R (resin)- the crowns were sectioned at the level of the cementoenamel junction and restored with metallic cast posts or resin build-up cores, respectively. The crowns were fabricated in ceramic IPS e.max® Press (Ivoclar Vivadent, Schaan, Liechtenstein) and luted with Variolink II. After 7 days of water storage, 5 specimens of each group were sectioned in buccolingual direction for microhardness measurements. The other specimens (N=5) were kept stored in deionized water at 37ºC for three months, followed by sectioning and microhardness measurements.

Results: Data were first analyzed by three-way ANOVA that did not reveal significant differences between thirds and occlusal surface (p=0.231). Two-way ANOVA showed significant effect of substrates (p<0.001) and the Tukey test revealed that microhardness was significantly lower when crowns were cemented on resin cores and tested after 7 days of water storage (p=0.007).

Conclusion: The type of material employed for coronal reconstruction of preparations for prosthetic purposes may influence the cement properties.

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Box plots: a) results after 7 days in water storage; b) results after 3 months inwater storage
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f04: Box plots: a) results after 7 days in water storage; b) results after 3 months inwater storage

Mentions: Data were analyzed by three-way ANOVA (substrates, thirds, and storage). Consideringeach factor independently, the substrates showed significant differences (p=0.000),without differences for factors storage (p=0.573) or thirds (p=0.231) (Table 1). There were interactions betweensubstrates and storage time factors (p=0.011). Since the analysis did not revealsignificant differences between thirds, the values of substrate and storage weresubmitted to two-way ANOVA, which showed significant effects of core materials(p<0.001). Hardness values were significantly lower when crowns were cemented onresin cores and measured after 7 days of storage (p=0.007) (Table 2, Figure 4).


Effects of coronal substrates and water storage on the microhardness of a resin cement used for luting ceramic crowns.

Mendonça LM, Pegoraro LF, Lanza MD, Pegoraro TA, Carvalho RM - J Appl Oral Sci (2014 Jul-Aug)

Box plots: a) results after 7 days in water storage; b) results after 3 months inwater storage
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4126824&req=5

f04: Box plots: a) results after 7 days in water storage; b) results after 3 months inwater storage
Mentions: Data were analyzed by three-way ANOVA (substrates, thirds, and storage). Consideringeach factor independently, the substrates showed significant differences (p=0.000),without differences for factors storage (p=0.573) or thirds (p=0.231) (Table 1). There were interactions betweensubstrates and storage time factors (p=0.011). Since the analysis did not revealsignificant differences between thirds, the values of substrate and storage weresubmitted to two-way ANOVA, which showed significant effects of core materials(p<0.001). Hardness values were significantly lower when crowns were cemented onresin cores and measured after 7 days of storage (p=0.007) (Table 2, Figure 4).

Bottom Line: The success of cementation depends on the achievement of adequate cement curing.Data were first analyzed by three-way ANOVA that did not reveal significant differences between thirds and occlusal surface (p=0.231).The type of material employed for coronal reconstruction of preparations for prosthetic purposes may influence the cement properties.

View Article: PubMed Central - PubMed

Affiliation: Department of Prosthodontics, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.

ABSTRACT

Unlabelled: Composite resin and metallic posts are the materials most employed for reconstruction of teeth presenting partial or total destruction of crowns. Resin-based cements have been widely used for cementation of ceramic crowns. The success of cementation depends on the achievement of adequate cement curing.

Objectives: To evaluate the microhardness of Variolink® II (Ivoclar Vivadent, Schaan, Liechtenstein), used for cementing ceramic crowns onto three different coronal substrate preparations (dentin, metal, and composite resin), after 7 days and 3 months of water storage. The evaluation was performed along the cement line in the cervical, medium and occlusal thirds on the buccal and lingual aspects, and on the occlusal surface.

Material and methods: Thirty molars were distributed in three groups (N=10) according to the type of coronal substrate: Group D- the prepared surfaces were kept in dentin; Groups M (metal) and R (resin)- the crowns were sectioned at the level of the cementoenamel junction and restored with metallic cast posts or resin build-up cores, respectively. The crowns were fabricated in ceramic IPS e.max® Press (Ivoclar Vivadent, Schaan, Liechtenstein) and luted with Variolink II. After 7 days of water storage, 5 specimens of each group were sectioned in buccolingual direction for microhardness measurements. The other specimens (N=5) were kept stored in deionized water at 37ºC for three months, followed by sectioning and microhardness measurements.

Results: Data were first analyzed by three-way ANOVA that did not reveal significant differences between thirds and occlusal surface (p=0.231). Two-way ANOVA showed significant effect of substrates (p<0.001) and the Tukey test revealed that microhardness was significantly lower when crowns were cemented on resin cores and tested after 7 days of water storage (p=0.007).

Conclusion: The type of material employed for coronal reconstruction of preparations for prosthetic purposes may influence the cement properties.

Show MeSH
Related in: MedlinePlus