0000000000187425
AUTHOR
Mojgan Kachoei
Effect of surface treatment with sandblasting and Er,Cr:YSGG laser on bonding of stainless steel orthodontic brackets to silver amalgam
Objectives: Satisfactory bonding of orthodontic attachments to amalgam is a challenge for orthodontists. The aim of this in vitro study was to compare the shear bond strength of stainless steel orthodontic brackets to silver amalgam treated with sandblasting and Er,Cr:YSGG laser. Study Design: Fifty-four amalgam discs were prepared, polished and divided into three groups: In group 1 (the control group) the premolar brackets were bonded using Panavia F resin cement without any surface treatment; in groups 2 and 3, the specimens were subjected to sandblasting and Er,Cr:YSGG laser respectively, before bracket bonding. After immersing in distilled water at 37°C for 24 hours, all the specimens w…
Does mechanical locking-base ceramic brackets reduce cracks at debonding?
Objectives: Debonding of chemically bonded ceramic brackets has been mostly led to enamel damages. This study aimed to evaluate enamel cracks followed by debonding ceramic brackets with mechanical retention. Study Design: Sixty extracted human premolar teeth were randomly divided into two groups. Metallic brackets and recently available ceramic brackets with mechanical retention were bonded to the teeth in first (MB) and second (CB) group respectively. After a week, the brackets were debonded using a pair of bracket-removing pliers assembled to a testing machine. Optical stereomicroscope and trans-illumination techniques were used to calculate the cracks and measure their length before bond…
Bolton's intermaxillary tooth size ratios among Iranian schoolchildren.
Objectives: The aims of the present study were to determine anterior and total tooth-width ratios in a representative Iranian sample in Tabriz city and compare them with the Bolton standards. Study design: A total of 54 Iranian schoolchildren (12-14 years old) in Tabriz were examined. Alginate impressions were taken for subjects and poured by the dental stone. The mesiodistal widths of the teeth were measured using a digital caliper. The overall and anterior Bolton's intermaxillary tooth size ratios for each model pair was calculated. Results: There were no significant differences (p > 0.05) between the right and left sides of the dental arch and a symmetry in size exists. There were no sig…
Arch width changes in patients with Class II division 1 malocclusion treated with maxillary first premolar extraction and non-extraction method
Background The aim of this study was to determine arch width changes during maxillary first premolars extraction and non-extraction treatment in patients with Class II division 1 malocclusion. Material and methods Dental casts of 91 Class II division 1 patients (36 males and 55 females) were evaluated. The minimum age of the subjects at the beginning of treatment was above 16 years. 48 patients were treated with extraction of the maxillary first premolars and 43 patients were treated without extraction. Pre- and post-treatment maxillary and mandibular inter-canine and inter-molar arch widths were measured. Results At the end of treatment, maxillary and mandibular inter-canine widths of both…