Miniplates

Miniplates are another form of skeletal anchorage used in orthodontics. Miniplates are often used when the necessary forces are presumed to be high due to their lower risk for failure when compared to mini-screws.76 They are made of titanium or a titanium alloy and typically consist of a head, arm, and body. The body is placed typically by an oral surgeon below the periosteum and is attached to the bone with a series of small screws.77 The plates are usually placed in the zygomatic buttress or piriform rim of the maxilla. In the mandible, they can typically be placed anywhere except for on the mental nerve.78 The body is connected to an arm that extends into the mouth with a head that is designed to allow placement of force for orthodontic tooth movement.77 Potential complications with miniplate use include facial swelling directly after surgical placement, plate loosening, plate fracture, and mucosal dehiscence around the plate.78

Several of the uses of miniplates are similar to those of TADs. The use of miniplates reduces the concern of proximity to adjacent teeth. One unique application of miniplates is their use in Class III patients for bone anchored maxillary protraction or BAMP (Figure 5). For this use, miniplates are placed bilaterally in the infrazygomatric crests of the maxilla and in the anterior mandible. Elastics are worn on each side from maxillary miniplate head to the mandibular miniplate head. Results of BAMP have shown anterior displacement of the zygoma and maxilla with minimal dental movement, posterior displacement and clockwise rotation of the mandible, and posterior displacement of the glenoid fossa.79,80

Figure 5.
Photo of Class III elastic force from maxillary miniplate to mandibular miniplate
Image of Class III elastic force from maxillary miniplate to mandibular miniplate
Class III elastic force from maxillary miniplate to mandibular miniplate in a 10 year old patient with a Class III tendency.

Another unique use of miniplates consists of placement on the lateral nasal walls of the maxilla and use as anchorage for facemask elastics in maxillary deficient patients. Research has shown anterior movement of the infraorbital region and maxilla using this protocol in the late mixed dentition.81 Sar et al. found that the addition of miniplates in this procedure reduced the unwanted side effects of conventional facemask use, including less dental movements, less maxillary rotation, and more maxillary advancement.82 This can also be used in patients with cleft palate or cleft lip and palate to treat maxillary hypoplasia commonly seen in these patients.83