An in vitro investigation into the effects of retained coronal dentine on the strength of a tooth restored with a cemented post and partial core restoration

Aim This study aimed to examine the fracture resistance of teeth restored with cast post and partial cores supported by different heights of coronal tooth structure. Methodology Four specimen groups were prepared. Group A was the control and consisted of 10 single-rooted teeth restored with post and cores cemented in dowel channels with no retained coronal dentine. The test groups, B, C and D differed in the amount of retained buccal coronal dentine having 3, 4 and 5 mm, respectively. All groups were tested to failure using an Instron Universal Testing Machine, Model 1195. The mode of failure for representative specimens for each group was recorded photographically. Results Specimens in group B where the remaining dentine core was 3 mm in height fractured at a higher force than specimens in the control group (P = 0.0239). There were no statistically significant differences in the forces required to fracture teeth with retained buccal coronal dentine cores of 4 and 5 mm when compared to the control. There was no statistically significantly difference between forces required to fracture groups B and C or groups B and D. Conclusion In this in vitro study, 3 mm of retained coronal buccal dentine improved fracture resistance of teeth restored with partial post and cores when compared to teeth without retained coronal dentine.