A Three Dimensional Comparative Study of Two Rapid Maxillary

Mosleh, M. A. I. E. - S., M. A. Kaddah, and F. A. Abd, A Three Dimensional Comparative Study of Two Rapid Maxillary, , Egypt, Cairo University, 2013.

Thesis Type:

M.Sc Thesis


Maxillary constriction is considered one of the common orthodontic problems
that could be accompanied by unilateral or bilateral posterior cross-bite narrow
nasal cavity, and dental crowding. Aim: The purpose of this study was to evaluate
and to compare three dimensionally the dento-skeletal changes concurrent with
tooth-borne and bone-borne rapid maxillary expanders. Material and methods:
The study was conducted on 20 growing female patients with a mean age of 12±2
years old . They weredivided into two equal groups; the first group was treated by
tooth borne (Hyrax) expander supported by four stainless steel bands, whereas the
second group received bone borne (Hyrax) expanders anchored directly to the
palatal bone through four mini-screws. Orthodontic study models, intra- and extraoral
photographs, and cone beam computed tomography( CBCT) images were
taken before and immediately after treatment were taken. Cone beam computed
tomography scans was the tool of assessment in this comparative study. Results:
On comparing both groups,subjects in tooth borne expander group showed a
significant increase in nasal widths (P =0.018 ). There was a higher significant
increase in intercuspal widths of first premolars (P =0.046 ) and first permanent
molars ( P = 0.015) noticed in the tooth borne group. The tooth borne group
resulted in a higher significant increase in thebuccolingual inclination ( buccal
rolling ) of the upper first premolars compared to the bone borne group.
Superimpostionof three dimensional images revealed skeletal expansion in canine,
first premolar and first molar regions in both groups. Conclusion: The greatest
skeletal and dental changesoccuredin the transverse dimension in both expanders
whereas, the vertical and anteroposterior changes were minute. Both groups
produced basal bone expansion at the level of the hard palate. Regarding the dental
expansion, the tooth borne expander produced more dental expansion than bone
borne expander resulting in a buccal rolling effect in the upper first premolar teeth.
As for the nasal width changes, there was a greater increase noticed in the tooth
borne expander group.

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