Date of Award

Spring 2002

Document Type

Thesis - Restricted

Degree Name

Master of Science (MS)

Department

Dentistry

First Advisor

Bradley, Thomas

Second Advisor

Villalobos, Francisco

Third Advisor

Race, Kevin

Abstract

A relrospective study was conducted to evaluate if the use of the modified pendulum appliance had similar or more desirable effects on distalization of maxillary molars and the anchorage loss on maxillary premolars and maxillary incisors. lnitial and follow-up cephalometric radiographs were obtained on 18 subjects (9 females and 9 males) who were treated with the modified pendulum appliance for bi lateral distalization of the maxillary first molar teeth, for correction of the Class ll molar relationship or for gaining space in the maxillary arch. Initial and follow-up dental casts were also obtained for all subjects. Dental, skeletal and soft tissue changes were determined. The mean maxillary molar distalization was 2.33 mm. with a djstal tipping of 5.00°. The mean reciprocal mesial movement of the first premolar was 3.23 mm, with a distal tipping of 0.25°. while that for the second premolar was 2.94 mm. with a distal tipping of 0.69°. All maxillary teeth extruded, except the second molar, which remained unchanged in the vertical dimension. However. the maxillary second molar moved distally 2.82 mm, with a distal tipping of 8.75°. The maxillary first molar extruded 0.43 mm. The first and second premolars extruded 2.23 mm and 1.36 mm. respectively. The maxillary central incisor was protruded 1.59 mm and proclined 1.52°. The transverse width of the distalized first molar was almost three times greater between the mesiobuccal cusps than between the distobuccal cusps. Therefore, a favorable mesiobuccal rotation was noted on the distalized maxillary first molars. The eruption of the maxillary second molars had a minimal effect on the distalization of the first molars: however. it did increase the extrusion of the maxillary premolars. The skeletal and soft tissue effects were similar to those of the original pendulum appliance. The mean amount of molar distalizayion in this study contributed to 45% of the total space created, whereas the remaining 55% was due to the reciprocal anchorage loss. Therefore, it appears that the modified pendulum appliance is effective in reducing the amount of distal tipping of the first molars and providing a favorable mesiobuccal rotation, but these come at the expense of more anchorage loss.

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