Javad Chalipa; Mehrnoush Momeni Roochi; Mahsa Mortazavi; Elahe Soltanmohamadi Borujeni; Sarvin Sarmadi; Maryam Khodabakhshi; Mohammad Hashem Hosseini
Abstract
Background: Severe skeletal class III malocclusions usually need a combined treatment of orthodontics and orthognathic surgery. Knowing about changes occurred following such treatments lead to improve facial esthetics and better treatment results.
Objectives: This study was done to determine cephalometric ...
Read More
Background: Severe skeletal class III malocclusions usually need a combined treatment of orthodontics and orthognathic surgery. Knowing about changes occurred following such treatments lead to improve facial esthetics and better treatment results.
Objectives: This study was done to determine cephalometric changes of facial soft tissue after combined treatment in patients with skeletal class III problem.
Methods: 25 patients with skeletal class III discrepancy who needed a combined treatment, were selected. Changes in nasolabial angle , upper lip and lower lip to E-line distance, angle of convexity , lip-chin-throat angle and lower anterior facial height were measured before and 6 - 12 months after surgery. Changes in parameters were analyzed with Paired t-test. Results: Upper lip to E-line distance (P < 0.0001) and angle of convexity (P < 0.001) changed significantly following surgical procedures while changes of other parameters were not significant.
Conclusions: Clinical changes in the soft tissue following a combination of orthodontic treatment and orthognathic surgery in patients with skeletal class III discrepancy are significant while these changes mostly improves esthetics of patient’s facial profile.
Mohammad Hashem Hosseini; Ardavan Etemadi; Fatemeh Gorjizadeh
Abstract
Background: Application of zirconia in dentistry has increased due to its good properties. Since zirconia is not possible to be etched, evaluation of the other methods of surface treatment is important.
Objectives: The aim of this study was to evaluate zirconia surfaces treated by different output powers ...
Read More
Background: Application of zirconia in dentistry has increased due to its good properties. Since zirconia is not possible to be etched, evaluation of the other methods of surface treatment is important.
Objectives: The aim of this study was to evaluate zirconia surfaces treated by different output powers of Er: YAG laser and sandblasting technique by scanning electron microscope (SEM). Materials and Methods: 15 specimens were prepared of 3Y-TZP ceramic material. After polishing of all the samples, divided into 5 groups; control group, 1.5 W Er: YAG laser irradiated group, 2.5W Er: YAG laser irradiated group, 3.5 W Er: YAG laser irradiated and sandblasted group. Then SEM image of each group were prepared and analyzed. Results: The SEM images of study groups showed there is no significant difference between control group and laser groups at × 3000, but at the more magnifications (× 15000 and × 60000), with increasing laser power, surface roughness and deformation of crystals increases. SEM of Sandblasted group showed a change in surface texture with the formation of microretentive grooves and deformation of zirconia crystals shape.
Conclusions: By increasing the Er: YAG laser power on zirconia ceramics, the surface roughness increases but not impressive. Application of sandblasting technique on zirconia provides greater surface roughness than Er: YAG laser treatment. 1.5 W (150 mJ) Er: YAG laser radiation has no significant effect on surface morphology of zirconia but 2.5 W (250 mJ) and 3.5 W (350 mJ) outputs, change the surface morphology.
