Enamel wear by antagonistic restorative materials under erosive conditions.

OBJECTIVES

This study aimed to analyse loss of enamel worn against composite, leucite glass ceramic or enamel antagonists under non-erosive and alternating or simultanuous erosive-attritive conditions.

MATERIALS AND METHODS

Flat human enamel specimens were loaded (1 Hz, 300 g loading weight, each subgroup n = 12) with antagonists made from a hybrid-composite (Z250, 3 M Espe), a nano-composite (Filtek Supreme XTE, 3 M Espe), leucite glass ceramic (IPS Empress CAD LT, Ivoclar Vivadent) or enamel. Specimens were either submitted to mechanical loading in mineral solution (60 s) or to loading under alternating or simultaneous erosive conditions. For alternating erosion-attrition, specimens were eroded by citric acid (pH 2.6, 60 s) and then loaded with the respective antagonist for 60s. For simultaneous erosion-attrition, specimens were loaded with the respective antagonist while being immersed in citric acid (pH 2.6, 60 s). After each cycle, specimens were stored in water for 1 h. After 18 cycles, enamel loss was calculated profilometrically and statistically analysed by two-way ANOVA and Tukey's post-hoc tests (p < 0.05).

RESULTS

Enamel loss (μm, mean ± standard deviation) was significantly highest for simultaneous erosion-attrition (ceramic 9.4 ± 1.1, hybrid-composite 8.3 ± 0.7, nano-composite 7.8 ± 1.2, enamel 7.4 ± 0.8) followed by alternating erosion-attrition (ceramic 3.5 ± 0.5, hybrid-composite 2.1 ± 0.8, nano-composite 1.0 ± 0.2, enamel 2.5 ± 0.7) and attrition in mineral solution (ceramic 0.5 ± 0.3, hybrid composite 0.3 ± 0.1, nano composite 0.1 ± 0.2, enamel 0.1 ± 0.1). Ceramic antagonists resulted in significantly higher loss than the remaining antagonistic materials when alternating or simultaneous erosion-attrition was performed.

CONCLUSION

Erosive conditions had a massive impact on enamel worn against different antagonistic materials, with simultaneous erosive-attritive conditions being more detrimental than alternating erosive-attritive conditions.

CLINICAL RELEVANCE

Enamel wear by antagonistic restorative materials is significantly influenced by erosive conditions.