Early Orthodontic Treatment by Antonio Patti

Author:Antonio Patti [Antonio Patti]
Language: nld
Format: epub
ISBN: xxxx
Publisher: Quintessence International

Secondary crowding

Secondary crowding is functional in origin and occurs when there has been a reduction in arch length, mandibular incisors are lingually inclined, or primary teeth have been shed in atypical order.

Reduction in arch length (perimeter). This can result from interproximal dental caries in primary teeth or the premature loss of a primary second molar with a resultant crowding in the buccal segment. In these ways, the space that primary molars should have preserved by their very presence may be encroached upon. Whenever it finds a mesial space to occupy, an erupting permanent first molar will tend to move into that space.

Immediately after premature extraction of a primary second molar, if the permanent first molar is already present, the orthodontist must be sure that the space is preserved with one of the following devices, which are described in detail in chapter 6: a unilateral space maintainer whose mesial extensions abut the distal surface of the primary first molar, a bilateral space maintainer from permanent molar to permanent molar contacting the lingual surfaces of the incisors, or a Nance palatal arch for maintaining space in the maxillary arch.

If the space maintainers have not been placed in a timely fashion, and the permanent molars have begun to move mesially, the orthodontist must recover the lost space with an appropriate appliance to ensure that space is available for eruption of the second premolars.

To regain space in the mandibular arch, the orthodontist can use a lip bumper (Fig 5-11). Lip pressure on the appliance will transmit force to the molars, moving them distally while at the same time cutting off unwanted centripetal pressure on the incisors (see chapter 6). A removable appliance with a screw or spring can be used to distalize molars (see chapter 6). A utility arch works effectively when the orthodontist not only needs to recapture lost space but also has to intrude the mandibular incisors or move them labially.

In the maxillary arch, space can be gained with a transpalatal bar that can either be soldered to the molar bands or inserted into lingual tubes on them. When the bar is activated, it distalizes those molars (see chapter 6). A removable appliance with distalizing springs or screws can also be used (see chapter 6). Extraoral force remains a useful technique for distalizing molars but requires good cooperation from the young patient, among other inconveniences.

A quadhelix can be used if expansion is also indicated. When activated correctly, this device not only expands but also moves molars distally (see chapter 6).

Fig 5-11a The patient exhibits maxillary and mandibular crowding.

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