[EP-12] Preparation Modification and Convergence Angle of Short Abutment Teeth to Improve Retention and Resistance of Fixed Restorations
[Abstract]
[Objective]
To determine the effect of preparation modification and convergence angle in short abutment teeth on retention and resistance of fixed restoration.
[Method]
Prepared brass rod with a height of 3 mm and a width of 11 mm, with convergence angle of 10° and 22° and and preparation modifications in the form of grooves and boxes. A total of 30 samples were divided into 6 groups (n = 5) based on convergence angle and preparation modification. Retention and resistance tests were performed using a universal testing machine.
[Results and Discussion]
The effect of convergence angle on retention and resistance is evaluated using Independent t-test showing p = 0.0001 while the effect of preparation modification on retention and resistance was evaluated using ANOVA test showing p = 0.0001. The preparation modification of groove and box will increase the surface area, resulting in increased cement adhesion surface area and increased retention, in addition, the resistive area will also increase due to the role of mechanical interlocking. A convergence angle of 10° will increase retention and resistance because it has a single path of placement, while a convergence angle of 20° or more have multiple path of placement and will change the cement interface, the particles of the cement will tend to lift away from rather than slide along the preparation. In the case of short abutment teeth, the addition of preparation modifications in the form of grooves or boxes can significantly increase retention and resistance values. Box preparation modification results in greater retention and resistance than groove preparation modification.
[References]
1) AlShaarani F, et al. An auxiliary factor for increasing the retention of short abutments. Heliyon. 2019; 5(10): e02674.
2) Roudsari RV, Satterthwaite JD. The influence of auxiliary features on the resistance form of short molars prepared for complete cast crowns. J Prosthet Dent 2011;106(5):305-9.
3) Parker MH. Resistance form in tooth preparation. Dental Clinics. 2004;48(2):387-96.
4) Narula S, et al. Retention in conventional fixed partial dentures: A review. J. Clin. Diagn. Res. 2011;5: 1128-33.
[Objective]
To determine the effect of preparation modification and convergence angle in short abutment teeth on retention and resistance of fixed restoration.
[Method]
Prepared brass rod with a height of 3 mm and a width of 11 mm, with convergence angle of 10° and 22° and and preparation modifications in the form of grooves and boxes. A total of 30 samples were divided into 6 groups (n = 5) based on convergence angle and preparation modification. Retention and resistance tests were performed using a universal testing machine.
[Results and Discussion]
The effect of convergence angle on retention and resistance is evaluated using Independent t-test showing p = 0.0001 while the effect of preparation modification on retention and resistance was evaluated using ANOVA test showing p = 0.0001. The preparation modification of groove and box will increase the surface area, resulting in increased cement adhesion surface area and increased retention, in addition, the resistive area will also increase due to the role of mechanical interlocking. A convergence angle of 10° will increase retention and resistance because it has a single path of placement, while a convergence angle of 20° or more have multiple path of placement and will change the cement interface, the particles of the cement will tend to lift away from rather than slide along the preparation. In the case of short abutment teeth, the addition of preparation modifications in the form of grooves or boxes can significantly increase retention and resistance values. Box preparation modification results in greater retention and resistance than groove preparation modification.
[References]
1) AlShaarani F, et al. An auxiliary factor for increasing the retention of short abutments. Heliyon. 2019; 5(10): e02674.
2) Roudsari RV, Satterthwaite JD. The influence of auxiliary features on the resistance form of short molars prepared for complete cast crowns. J Prosthet Dent 2011;106(5):305-9.
3) Parker MH. Resistance form in tooth preparation. Dental Clinics. 2004;48(2):387-96.
4) Narula S, et al. Retention in conventional fixed partial dentures: A review. J. Clin. Diagn. Res. 2011;5: 1128-33.