Which item is required to tighten a functional appliance during an adjustment appointment?

To tighten a functional appliance during an adjustment appointment, Adams pliers are essential. These pliers are specifically designed to grasp and manipulate orthodontic components, making them ideal for adjusting functional appliances. The configuration of Adams pliers, which includes pointed beaks that can easily grip small parts, allows dental professionals to apply the necessary torque or pressure to tighten screws or components of the appliance effectively.

Other tools, such as Alastik holders, are typically used for placing or removing elastic bands, which are not directly related to the adjustment of functional appliances. Band removers are designed for removing bands from teeth but do not assist in tightening appliances. End cutters are used primarily for cutting wires or excess material, rather than making adjustments to existing structures. Thus, Adams pliers are the correct choice for this specific task in a dental setting.