the anterior segment where the intrusion arch was engaged. Dr. Burstone also believed in using low magnitude forces to achieve the desired intrusion. This type of intrusion has a single point of application of force system which allows one to devise what type of force is being generated. This type of system is known as Statistically determinate system. Rickett's Utility intrusion arch Robert M. Ricketts developed the Utility arch in 1950s and it is considered to be an integral part of the Bioprogressive Therapy in Orthodontics. His utility arch is a continuous wire that is engaged in a posterior 1st permanent molar tooth and front four incisors. His utility arch consists of 5 segments: Molar segments, Posterior Vertical Segment, Vestibular segment, anterior vertical segment and incisal segment. The incisal segment lies passively in the incisal brackets of the anterior teeth. This type of intrusion arch employs a statistically indeterminate system. Activation of the intrusion arch is done by placing occlusally pointed gable bend at the posterior portion of the vestibular segment. This allows the anterior portion of the wire to passively sit in the vestibule and when engaged in the anterior teeth, puts forces on the incisors. Three-Piece intrusion arch This type of intrusion arch was developed by Shroff et al. in 1992. This arch also has 3 segments in one arch. The anterior segment has a vertical bend distal to the lateral incisors with a posterior extension to which the intrusion cantilever springs are engaged bilaterally. This type of intrusion was developed to achieve retraction and intrusion simultaneously in a treatment where upper first premolars are extraction. The retraction can be performed by using either an elastomeric chain or Niti Coil Spring which connects the distal extension of the anterior segment and the hook on the posterior molar tube. Activation of the cantilever is done by making a bend mesial to the molar tube which allows the intrusion arch to be in vestibule when it's passive. Type of cases An orthodontic patient can present with different types of malocclusion and facial growth patterns. Intrusion of teeth can be used in patients with deep bite cases who may have a vertical or a horizontal growth pattern or open bite cases which may involve intrusion of posterior teeth. Deep bite with vertical facial growth pattern In these types of cases, it is essential to manage the vertical growth of a patient.