Orthodontics
Farzin Razavi; Behnam Khosravanifard; Sheida Kamrooz; Shahla Kamrouz
Abstract
Aim: The present study tried to find the proper bonding and debonding technique to preserve the natural enamel surface and avoid its discoloration.Methods: Sixty newly extracted human premolars were randomly divided into three groups, and three orthodontic adhesives were applied to bond the brackets: ...
Read More
Aim: The present study tried to find the proper bonding and debonding technique to preserve the natural enamel surface and avoid its discoloration.Methods: Sixty newly extracted human premolars were randomly divided into three groups, and three orthodontic adhesives were applied to bond the brackets: chemically cured System 1 Plus adhesive (Ormco, USA) (CC), light-cured resin (Transbond XT, 3Munitek, USA) (LC), and resin-modified glass ionomer cement (Fuji Japan) (GI). The specimens were immersed in black tea for one week and debonded, and four prophylactic methods were applied to remove residual resin: 1) tungsten carbide bur (TC), 2) tungsten carbide bur + Sof-Lex polisher (TC + SL), 3) tungsten carbide bur + One Gloss Polisher (TC + OG), and 4) tungsten carbide bur + Po-Go polisher (TC + PG). The enamel color was measured according to the CIE standard system (Commission Internationale de l’Eclairage) by Konica Minolta CS Spectroradiometer equipment twice: 1) natural enamel color before bonding and 2) after bonding, staining, debonding, and polishing. The ΔE value is the tooth discoloration, which is measured from the mean Δa*, Δb*, and ΔL* values using the following formula ΔE = [(ΔL*)2 + (Δa*)2 + (Δb*)2]1/2 for each group. Then, it was statistically analyzed using a t-test.Results and Conclusions: Regarding adhesive materials, CC adhesive showed higher discoloration than LC in all the polishing methods. The lowest discoloration was observed in GI. The highest ΔE* values were obtained using TC only, which was deemed insufficient to remove the residual adhesives. Applying TC + Sof-Lex and TC + PoGo equally enhanced the results; therefore, they were the best polishing methods.
Behnam KhosravaniFard; Asal Fetrati; Hesam Rahimi; Elmira Asadi
Abstract
Since the publication of Angle’s definition of malocclusion types, many cephalometric researches have been carried out to determine characteristics of Class II division 2 malocclusions; however controversies still remain.
Considering the fact that a high percentage of patients seeking orthodontic ...
Read More
Since the publication of Angle’s definition of malocclusion types, many cephalometric researches have been carried out to determine characteristics of Class II division 2 malocclusions; however controversies still remain.
Considering the fact that a high percentage of patients seeking orthodontic treatment have this malocclusion, the present study was conducted in order to investigate Cross-Sectionally the cephalometric characteristics of Class II/2 malocclusions in 8-12 years old patients of Tehran Orthodontic Clinics.
Patients’ files and pretreatment dental casts were screened, 30 Class II Division2 (17 girls, 13 boys) and 30 normal occlusion subjects were selected, each lateral cephalograms was traced and 36 dental and skeletal parameters were measured. Moreover student t test was carried out to assess the differences between malocclusion groups. Besides maxillary incisal position (retruded in class II/2 group) which was used as an inclusion criterion, the following differences were observed:
1-The maxillary position is retruded compared to normal group.
2-The mandibular length is longer but its sagittal position is retruded.
3-The chin is more prominent.
4-The mandibular growth vector is horizontally oriented and the mandibular plane is flat, creating the appearance of a hypodivergent facial pattern. So Lower anterior facial height was on average smaller.
5-And finally retroclination of mandibular incisors compared to normal group is evident. These findings indicate that besides the dental characteristics, Class II/2 malocclusion patients are also skeletally different from normal occlusion group to a certain extent.