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Fracture Resistance of Endodontically Treated Maxillary Premolars with Non-carious Cervical Lesions Restored with
Wing See Fiona Leung1, Angeline Hui Cheng Lee1, Christopher Liu1
1Division of Endodontics, Restorative Dental Sciences, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China.
Objective:
To test the hypothesis that the (i) presence of non-carious cervical lesions (NCCLs) and (ii) type of post system have no effect on the fracture resistance and pattern in endodontically treated maxillary premolars.
Methods:
Human maxillary first premolars (n=60) with two root canals were randomly allocated into four groups (n=15). Buccal wedge-shaped NCCLs were prepared in 45 teeth specimens. Following root canal treatment, the specimens were randomly divided into (i) composite resin core (CRC); (ii) NCCLs + composite resin core (NCCL+CRC); (iii) NCCLs+prefabricated fibre-reinforced composite post + composite resin core (NCCL+PFRC+CRC); (iv) NCCLs+custom fibre posts + composite resin core (NCCL+CFP+CRC). All specimens were subjected to thermocycling (5°C to 55°C/5000 cycles). The compressive load was applied non-axially to the palatal cusp with a universal testing machine at a crosshead speed of 0.5 mm/min at a 30° angle until fracture. Fracture patterns were examined using a loupe magnification (2.5×) under transillumination. Statistical analyses were performed using non-parametric tests and pairwise comparisons of the load-to-fracture among the groups. Chi-square test was used to analyse the fracture patterns (P=0.05).
Results:
Fracture resistance of NCCL+PFRC+CRC was significantly higher than NCCL+CRC (P=0.011), while NCCL+CFP+CRC did not show any significant difference when compared to NCCL+CRC (P=0.089). No statistical difference was found between CRC, NCCL+PFRC+CRC and NCCL+CFP+CRC (P=1.000). The frequencies of favourable fracture patterns in descending orders were as follows: CRC (80%), NCCL+CFP+CRC (73%), NCCL+PFRC+CRC (60%), and NCCL+CRC (40%). Chi-square test did not show significant differences in fracture patterns among all groups (P=0.110).
Conclusion:
Restoration of the endodontically treated maxillary premolars with NCCLs, with or without post, resulted in similar fracture resistance as their counterparts without NCCLs. Placement of a prefabricated fibre-reinforced composite post exhibited greater fracture resistance to the maxillary premolars with restored NCCLs than those without a post. (EEJ-2022-06-077).
