Supervisors info:
Παπάζογλου Ευστράτιος, Αναπληρωτής Καθηγητής Οδοντικής Χειρουργικής.
Κακάμπουρα Αφροδίτη, Καθηγήτρια Οδοντικής Χειρουργικής.
Πελεκάνος Σταύρος, Επίκουρος Καθηγητής Ακίνητης Προσθετικής.
Notes:
Marginal gap of the restoration and the film thickness of the cement play important role in the long term survival rate of the onlays.
The purpose of this study was to evaluate the film thickness of the resin cement and so as indirectly the marginal gap of onlays manufactured by different materials (e.max CAD, composite Filtek Ultimate) and methods (digital impression-CAD/CAM restoration, analog impression and gypsum cast/PVS cast).
30 extracted molars without restorations were prepared by one operator for MOD onlays with specific criteria. After the preparations, immediate dentin sealing (IDS) was held and then the teeth were randomly divided in three groups of 10(n=10). In group A the impression was digital (Trios, 3Shape) and ceramic onlays were manufactured with CAD/CAM technology (e.max CAD – inLab Mc Xl ,Sirona). In group B composite onlays (Filtek Ultimate, 3M) were fabricated with a polyether impression (Impregum 3M ESPE) and a gypsum cast, while in group C composite onlays (Filtek Ultimate, 3M) were fabricated with a polyether impression (Impregum 3M ESPE) and a PVS cast (Mach 2, Parkell). Cementation of the onlays (Nexus NX3, Kerr) were followed by finishing and polishing, and afterwards the onlays were observed with the use of optical microscope, where the distance of the cement between the tooth and the restoration was recorded and the Mean Values of each group was calculated.
As far as statistics is concerned, Anova one-way (Levene’s test for homogeneity of variances) and t-test were held, with p=0.05. Ceramic onlays showed mean gap 16,77μm(±23,46μm), composite onlays on gypsum cast 16,10μm(±14,88μm), and composite onlays on PVS cast 16,93μm(±27,88μm.Anova showed no statistical significance within the three groups, regarding the mean gap. (F(2,1737)= 0.199, p= 0.81>>0.05). Furthermore, t-test statistics showed no significance between ceramic onlays (16,77±23,46μm) and composite onlays (16,54±22,67μm), t(1738)=0.20, p=0.84.
This study concluded that there is no statistical difference in the thickness of the resin cement , regarding the material used, the way of taking the impression and the fabrication cast. The mean values of the three groups of onlays were between the acceptable marginal gap of the literature. The results of this in vitro study should be enhanced by other in vitro and in vivo studies, in order to establish more significancefor the clinical practice.
