A comparison of the mechanical proprieties of different types of primary tooth restorations: an in vitro study

To compare the different restoration types of primary teeth to determine which type is appropriate for extensive caries of primary molars and incisors based on mechanical properties. A total of 160 primary teeth were evaluated in this study, including 80 incisors and 80 molars. Each category was divided into four groups: the control group, composite resin group, pre-veneered stainless steel crown (stainless steel crown) group, and zirconia crown group. Compressive strength test and fatigue strength test were performed. The compressive strength and fatigue strength of the composite resin group were significantly decreased compared with the control group (P < 0.05). The prefabricated crown groups showed increased fatigue and compressive strength compared with the control group, and the zirconia crown group was higher than that of the pre-veneered stainless steel crown group (P < 0.05). The zirconia crown group was less than the stainless steel crown group (P < 0.05) in the compressive strength but more than the stainless steel crown group (P < 0.05) in the fatigue strength. The compressive strength and fatigue strength of crown restoration were superior to that of the composite resin filling. The fatigue strength of the zirconia crown also performed better than the pre-veneered stainless steel crown and the stainless steel crown. The compressive strength of the zirconia crown was less than that of the stainless steel crown. The zirconia crown is a new restoration method for primary teeth that may be commonly applied in clinical practice.