Influence of sintering technique on fracture load of monolithic zirconia with different thicknesses

Aim This work aims to investigate and measure  different fracture loads produced by two different sintering procedures (high-speed  and traditional sintering) on different thicknesses of zirconia crowns.

Materials and methods Zirconia blanks (Vita/zahnfabrik diameter 98 mm x 12 mm height, Germany) were used to fabricate 48 molar crowns (N = 48, divided into 2 groups of 24) which were constructed in three different occlusal thicknesses (1.5, 2.0, 2.5 mm) using two methods: conventional sintering (1,450°C) and high-speed sintering (1,550°C). Crowns were bonded to  CoCr die. Fracture load was tested after all crowns were underwent 5,000 timesthermocycling test  (between 5°C and 55°C).

Result ANOVA analysis has been used to compare the fracture load of different groups, and results showed that high-speed sintering required significantly more force and load than conventional sintering (p-values 0.001).

Conclusion Time and money-saving technology showedencouraging  results that with zirconia crowns resulted in high-speed sintering and greater fracture loading values than the control group (conventional technique); also,  fracture load increased with  increase of thickness of zirconia crown. Therefore, it is recommended to increase occlusal thickness with high-speed sintering to obtain better resistance to chewing force.