Abstract:

Purpose: To evaluate color stability and fracture resistance of CAD/CAM and manually fabricated tooth colored materials as crowns on primary molars.
Methodology : Eighty epoxy replicas (Vertex- Dental B.V., The Netherlands) of minimally prepared primary molar were constructed to receive a tooth colored crown. Replicas were assigned into 4 groups (n=20) according to crown material used: CAD/CAM PMMA blocks (Telio Cad, Ivoclar Vivadent AG, Liechtenstein) [CC], self-polymerizing temporary resin material [SP] (Snap, Parkell, NY 11717 USA), auto-mix temporary resin material [AT] (Telio CS C&B Ivoclar Vivadent AG, Liechtenstein), and thermoplastic resin material [TP] (DurAcetal, Myerson LLC, Chicago, IL, USA). After cementation using glass ionomer cement (Vivaglass CEM, Ivoclar Vivadent AG, Liechtenstein), all specimens were thermo-cycled for 1000 cycles. Tooth shade was recorded using spectrophotometer , after storing in: orange juice, and carbonated beverage. Fracture resistance was assessed by axially loading the crowns using a universal testing machine . Data were analyzed using one-way analysis of variance and post hoc tests (α=0.05).
Results: Spectrophotometric analysis revealed unacceptable color change of manually fabricated crowns; SP (∆E =5.4 ± 1.6), AM (∆E =6.7 ± 1.2) and TP (∆E =4.4 ± 2.5). On the other hand, CC crowns demonstrated high color stability (∆E=1.7 ± 0.2). CAD/CAM crowns demonstrated significantly higher fracture resistance (1417.9 ± 62 N) compared to manually fabricated crowns (SP=1096 ± 50, AM=989 ± 41 and TP=1297 ± 45).
Conclusions: CAD/CAM PMMA crowns revealed superior fracture resistance and color stability properties suitable for long-term clinical performance within the primary molars.