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Online ISSN 1827-174X
Angerame D. 1, De Biasi M. 2, Del Lupo V. 1, Bevilacqua L. 1, Zarone F. 3, Sorrentino R. 3
1 University Clinical Department of Medical Surgical and Health Sciences, University of Trieste, Trieste, Italy;
2 Graduate School of Nanotechnology, University of Trieste, Trieste, Italy;
3 Department of Neurosciences, Reproductive and Odontostomatological Sciences University Federico II, Naples, Italy
AIM: The aim of the present microleakage study was to assess the sealing ability of nanohybrid composite crowns with different finish lines exposed to simulated mechanical periodontal treatment (SMPT).
METHODS: After sample size calculation (α=0.05; β=0.20; δ=1.0; σ=0.8), sixty extracted mandibular molars were divided into four groups (N.=15): G1, 90° shoulder; G2, beveled 90° shoulder; G3, 90° shoulder and SMPT; G4, beveled 90° shoulder and SMPT. Tooth preparations were carried out by means of diamond burs and Arkansas stones. The buildup of crowns was performed with a nanohybrid composite on master casts obtained after polyether impressions and crowns were cemented with self-adhesive cement. Groups G3 and G4 were subjected to the equivalent of five years of semestral mechanical periodontal scaling with Gracey curettes (2-mm long strokes, 5 N). Samples were immersed into a methylene blue supersaturated solution for 10 minutes. Microleakage was measured by stereomicroscopic observation of multiple sections of the samples and leakage data underwent statistical analysis with non-parametric tests.
RESULTS: Marginal microleakage was 1.53±1.27% and 17.60±12.72% of the length of the adhesive interface in G1 and G2, respectively. SMPT reduced dye penetration (P<0.001) with G3 not leaking at all and G4 leaking along the 5.58±1.84% of the adhesive interface. The bevel preparation significantly worsened the marginal seal both in control and treated crowns (P<0.001).
CONCLUSION: Microleakage of nanohybrid composite crowns increased by adding a bevel to a 90° shoulder preparation and diminished after SMPT.
language: English, Italian