Orthodontists deliver Phase 1 treatment early, before all permanent teeth erupt. In addition, this early care begins correcting harmful malocclusions or poor bites that may worsen over time. As a result, early intervention can prevent issues that might become more difficult or impossible to treat later. However, Phase 1 treatment does not replace conventional orthodontics typically done during adolescence. For example, orthodontists may use Phase 1 treatment to correct individual tooth or jaw crossbites, severe underbites, and overbites when functional, aesthetic, or psychological concerns arise.