Harris, AngelaCoetsee, Marthinus Johannes2023-04-182024-06-042023-04-182024-06-042022https://hdl.handle.net/10566/15869Magister Scientiae Dentium - MSc(Dent)The effect of extraction and non-extraction treatment protocols on the dental arch width has comprehensively been researched. The effect of non-extraction protocols using passive selfligating systems has also been adequately investigated. Although the literature comes to contrasting conclusions and further research is always encouraged, the impact on the dental arch width using an extraction protocol in combination with a passive self-ligating system has not been defined thoroughly. Aim: this study investigated the effect of 2 treatment protocols on transverse arch width, before and after treatment, using a passive self-ligating system. The null hypothesis to be tested was that treatment with a second premolar extraction protocol would result in no difference in transverse arch width changes compared to treatment with a non-extraction protocol.enArch widthChange in arch dimensionsDamon systemSelf-ligating systemNon-extractionUniversity of the Western Cape