No abstract

Introduction: Orthodontics has been advocating extraction as a treatment option for over a Century. Some concerns have been raised regarding dental extractions in orthodontics. Some clinicians suggested that extraction would lead to arch collapse resulting in a narrower arch width. Yet others have reported that extraction treatment to correct malocclusion will not result in arch narrowing compared with similar non extraction protocols. However, it is well accepted that extraction treatment will involve changes in the arch dimensions. Aim of the study:The aim of the current study will be directed to investigate the changes in maxillary dental arch parameters concomitant to maxillary first premolar extraction in orthodontic treatment of Angle Class II dental malocclusion. Materials and methods:This prospective clinical trial was carried out in a two arm parallel design. A group of orthodontic patients with Angle Class II dental malocclusion, Division 1 and 2 (Total N= 17) and divided into two groups division 1 (N=10) and division 2 (N=7). Records were taken before treatment and after extraction and space closure in the maxillary arch. Both groups were compared regarding Arch width, Arch perimeter, Arch length and arch depth. Conclusion:We concluded that there was no significant difference in all pre-treatment readings between Class II division 1 and division 2 groups except for Arch perimeter, Upper incisor angulation and upper incisor tip where they showed a statistically significant difference. Regarding the amount of change between pre and post-extraction measurements in for Class II division 1 there was no significant difference except for arch length, inter-canine width, and arch perimeter. The amount of change between pre and post-extraction measurements in Class II division 2 showed no significant differences.

Ni‐Amalgame variierender Zusammensetzung werden in 0.1 ‐6 N NaOH‐Lösungen anodisch oxidiert.