 This study aimed to determine the effectiveness and duration of single-phase two-arch fixed appliance treatment and evaluate factors that may influence these variables. Data were collected from 177 consecutively completed cases at the orthodontic department, government, dental clinic, Singapore, during a three-month period. The results showed that two-arch fixed appliance treatment reduced metaclusions on average by 77.8% over a period of 25 months. Multiple regression techniques revealed that 22% of the variability in treatment effectiveness could be explained by pretreatment pass score, age at start of treatment, frequency of office visits and whether or not extractions were involved. The variation in treatment duration was due to frequency of office visits, pretreatment pass score, involvement of extractions or headgear. This article was authored by Chu Ming Tech and Sandham Andrew. We are article.tv, links in the description below.