الفهرس 
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Abstract
This study was designed to assess the efficiency of newly designed PMMA crowns by a novel method of fabrication for restoring pulpotomized primary molars in comparison to SSC’s and Zirconia Crowns. The study was carried out both In Vivo and In Vitro.
In Vivo:
Thirty full coverage restorations were used that were divided into 3 groups. group 1 (10 SSC’s), group 2 (10 Zirconia crowns), and group 3 (10 PMMA crowns). Fifteen children were included in the study who had bilateral decayed second molars, vital pulpotomy was performed, formocresol was used as a medicament, the pulp chamber was filled with IRM and teeth received full coverage restorations that were placed on the basis of split mouth design.
Colour parameters of each crown were obtained using a Vita Easyshade spectrophotometer after 6 months and after 12 months, gingival health was also recorded by using PI and GI after 6 months and after 12 months, patient’s satisfaction was also assessed.
In Vitro:
Thirty full coverage restorations (size 5), divided into 3 groups. group 1 (10 SSC’s), group 2 (10 Zirconia crowns), and group 3 (10 PMMA crowns) were used to assess their laboratory performance regarding the fracture resistance and surface roughness, crowns were cemented on their corresponding dies and were subjected to forces using universal testing machine, while the surface roughness Ra values were assessed using laser scanning technique
Our results showed acceptable colour stability of Zirconia crowns and PMMA crowns. No difference regarding the gingival health of the 3 different types of crowns. High patient satisfaction of Zirconia crowns and PMMA crowns in comparison to SSC’s.
While regarding the fracture resistance and surface roughness, PMMA crowns showed lower values in fracture resistance and higher surface roughness values in comparison to both SSC’s and Zirconia crowns which were still in the acceptable clinical range.