Objective: The aim of this study was to determine palatal and maxillary arch width
changes during MBT PEA with maxillary first premolars extraction treatment in patients
with Class II division 1 malocclusion.
Material and Methods: Dental casts of
24 Class II division 1 patients (8 males and 16
females) were evaluated. The minimum age of the subjects at the beginning of treatment
was above 16 years with mean age 02.02± 2.82. All patients were treated with extraction of
the maxillary first premolars and MBT PEA. Pre- and post-treatment maxillary and palatal
(inter-canine and inter-molar) widths were measured using a digital calliper of 0.01
accuracy. Paired samples t-test was used to evaluate the treatment changes within total
sample and within males group and females group. Differences between males and females
were tested using independent samples t-test.
Results: At the end of treatment, maxillary and palatal inter-canine widths increased
significantly (P>0.001).The maxillary inter-molar width increased but the values were
statistically insignificant (P<0.05). The palatal inter-molar width increased significantly
(P>0.01). No significant differences were observed between males and females.
Conclusions: Class II division 1 patients treated with extraction of maxillary first
premolars had tendency for an increase in palatal and arch width during treatment except
maxillary inter-molar width. It seems that a more thorough assessment and investigation
including pretreatment arch shape and factors related to anchorage should be carried out.
