RESULTS: Mean orthodontic bracket debonding force measured by the prototype device (9.36 ± 1.65 N) and the universal testing machine (10.43 ± 2.71 N) was not significantly different (p
METHODS: A total sample of 90 mandibular premolar teeth was divided into 2 groups (2 × 45 canals): the GP group and ER group. Each group was further divided into 3 subgroups (n = 15): cold lateral compaction (CLC), warm lateral compaction (WLC) and single cone (SC). The teeth were subsequently embedded in resin and sectioned horizontally at 1, 3, 6 and 9 mm. All sections were then viewed with a stereomicroscope at ×40 magnification. The area occupied by core filling materials was determined using Cell^D software.
RESULTS: With CLC, the percentage of core filling materials in the ER group was significantly higher than in the GP group at the 1- and 3-mm levels. Similarly, with WLC, the percentage of core filling material in the ER group was significantly higher than in the GP group at the 1-, 3- and 9-mm levels. With SC, the percentage of core filling materials in the ER group was significantly higher than in the GP group at all levels.
CONCLUSIONS: It can be concluded that the resin-coated GP/EndoREZ® sealer is superior to the gutta-percha/AH Plus in the percentage of core filling material.
METHODOLOGY: A total of 700 maxillary premolars were examined using CBCT in an Egyptian subpopulation. The number of roots was identified, and root canal configurations were classified according to Vertucci's classification and a new system for classifying root and canal morphology. In addition, the position where roots bifurcated and the levels where canals merged or diverged were identified. Fisher's exact test and independent t-test were used for statistical analysis, and the level of significance was set at 0.05 (P = 0.05).
RESULTS: More than half of maxillary first premolars were double-rooted, and the majority of maxillary second premolars were single-rooted (P
MATERIAL AND METHODS: The three-dimensional (3D) finite element program (ANSYS software) was used to construct the mathematical model. Two 5-unit FPD'S were simulated, one with rigid connector and another one with nonrigid connector. For analysis, each of these models were subjected to axial and oblique forces under progressive loading (180, 180, 120, 120, 80 N force on first and second molars, premolars and canine respectively) and simultaneous loading (100, 100, 100, 100, 100 N force on first and second molars, premolars and canine respectively).
RESULTS: The rigid and nonrigid connector design have effect on stress distribution in 5-unit FPDs with pier abutments.
CONCLUSION: Oblique forces produce more stresses than vertical forces. Nonrigid connector resulted in decrease in stress at the level of prosthesis and increase in stress at the level of alveolar crest.
METHODS: In 24 participants, 140-200 g of force was applied for mandibular canine retraction. Three MOPs were made according to the scheduled intervals of the 3 different groups: group 1 (MOP 4 weeks), group 2 (MOP 8 weeks), and group 3 (MOP 12 weeks) directly at the mandibular buccal cortical bone of extracted first premolars sites. Cone-beam computed tomography scans were obtained at the 12th week after MOP application. Computed tomography Analyzer software (version 126.96.36.199; Skyscan, Kontich, Belgium) was used to compute the trabecular alveolar BV/TV ratio.
RESULTS: A significant difference was observed in the rate of canine movement between control and MOP. Paired t test analysis showed a significant difference (P = 0.001) in the mean BV/TV ratio between control and MOP sides in all the frequency intervals groups. However, the difference was significant only in group 1 (P = 0.014). A strong negative correlation (r = -0.86) was observed between the rate of canine tooth movement and the BV/TV ratio at the MOP side for group 1 and all frequency intervals together (r = -0.42).
CONCLUSIONS: The rate of orthodontic tooth movement can be accelerated by the MOP technique with frequently repeated MOPs throughout the treatment.