IADR Abstract Archives
EFFECT OF DIFFERENT CUSP REDUCTION DESIGN AND THICKNESS TO FRACTURE RESISTANCE OF ENDODONTICALLY TREATED MAXILLARY PREMOLARS
Objectives: To evaluate the fracture resistance and fracture patterns of cusp-coverage resorations with different cusp reduction designs and thicknesses in endodontically treated maxillary premolars with MOD cavities.
Methods: 165 intact maxillary premolars were divided randomly into 11 groups: G1-9 (reduction groups with various designs and thickness), G10 (MOD group), G11 (intact). In reduction groups both cusps were reduced with combinations of different thicknesses and designs (Reduction thicknesses were: 1.5, 2.5 and 3.5 mm; reduction designs were beveled, horizontal and anatomic.) In all test groups (G1-10), root canal treatment with additional standardized MOD cavity preparation was applied on teeth. Cuspal coverage and MOD preperations were restored using composite resin. All specimens were submitted to 100.000 cycles with 50 Newton mechanical loading for artificial aging. Then, the specimens were subjected to a compressive load parallel to the long axis of the teeth at a crosshead speed of 0.5 mm/min until fracture. Two-way ANOVA and Fisher’s LSD test was used to identify statistical differences. The fractured samples were analyzed to determine the fracture pattern (restorable or non-restorable).
Results: The mean fracture resistance of all cusp-reduced groups (G 1-9) was higher than MOD group. Increased cusp reduction thickness increased the mean fracture resistance values. G6 (2.5 mm, anatomic, 1110.37 N) and G9 (3.5mm, anatomic, 1085.28 N) was significantly higher than MOD group (G10, 777.17 N); G6, G8 (3.5mm, horizontal,1039.10 N) and G9 was significantly comparable to the intact-premolar group (G11, 1640.80 N). The highest restorable fracture rates were observed in G6 and G9.
Conclusions: Cusp reduction design and thickness influenced the fracture resistance and fracture patterns of cusp-coverage restoration of endodontically treated maxillary premolars with MOD cavities. Teeth restored with anatomic cusp reduction design at least 2.5 mm reduction thickness had higher fracture resistance and restorable fractures.
Methods: 165 intact maxillary premolars were divided randomly into 11 groups: G1-9 (reduction groups with various designs and thickness), G10 (MOD group), G11 (intact). In reduction groups both cusps were reduced with combinations of different thicknesses and designs (Reduction thicknesses were: 1.5, 2.5 and 3.5 mm; reduction designs were beveled, horizontal and anatomic.) In all test groups (G1-10), root canal treatment with additional standardized MOD cavity preparation was applied on teeth. Cuspal coverage and MOD preperations were restored using composite resin. All specimens were submitted to 100.000 cycles with 50 Newton mechanical loading for artificial aging. Then, the specimens were subjected to a compressive load parallel to the long axis of the teeth at a crosshead speed of 0.5 mm/min until fracture. Two-way ANOVA and Fisher’s LSD test was used to identify statistical differences. The fractured samples were analyzed to determine the fracture pattern (restorable or non-restorable).
Results: The mean fracture resistance of all cusp-reduced groups (G 1-9) was higher than MOD group. Increased cusp reduction thickness increased the mean fracture resistance values. G6 (2.5 mm, anatomic, 1110.37 N) and G9 (3.5mm, anatomic, 1085.28 N) was significantly higher than MOD group (G10, 777.17 N); G6, G8 (3.5mm, horizontal,1039.10 N) and G9 was significantly comparable to the intact-premolar group (G11, 1640.80 N). The highest restorable fracture rates were observed in G6 and G9.
Conclusions: Cusp reduction design and thickness influenced the fracture resistance and fracture patterns of cusp-coverage restoration of endodontically treated maxillary premolars with MOD cavities. Teeth restored with anatomic cusp reduction design at least 2.5 mm reduction thickness had higher fracture resistance and restorable fractures.