Relapse tendency among different types of malocclusion

Abstract EN

Aims : The aim of this study is to evaluate the post-treatment changes in the dental parameters meas-ured at study models in group of Iraqi patients with different Angle's classes of malocclusions.

Mate-rials and Methods : 113 Iraqi patients (42 males and 71 females),of 14-29 years old at beginning of treatment, were randomly selected and longitudinally assessed in respect to relapse of their orthodonti-cally treated dentitions.

Stone study models were taken before treatment, after orthodontic treatment and a third set was obtained approximately 1 month out of retention.

Study models were photographed using a digital camera which is mounted on a height-adjustable tripod ; with standard camera to object distance.

Indirect computer digitization is used ; in which the photographs are entered to memory of Pentium IV computer and analyzed using View Box version 3 software allowing data to be directly digitized in the computer and analyzed with the SPSS program.10 variables are digitized : labial seg-ment ,buccal segment, vertical canine, vertical molar, diagonal arch length, inter canine width, inter-molar width, inter molar width, over bite and over jet.

Changes in measurements on study models from (before treatment) to (after treatment) were calculated and Paired Student's t- tests were employed to test the changes in means from (after treatment) to (after retention) ; at P = < 0.05 Results : The pooled sample was divided according to Angle's classifications into groups, the results indicate that the changes are varied and ranged from statistically non significant for some variables to significant for the rest.

While for Class I crowding patients ; the changes are small and statistically non significant for most variables.

For Class I spacing patients ; a tendency for relapse for most variables were observed.

In Class II.

D1 crowding, Class II.

D1 spacing, Class II.

D1 without crowding or spacing, CII.

D2 and Class III crowding patients some variables showed significant changes, and no significant difference for rest of variables.

Conclusion : Relapse (post-treatment changes) in the dental parameters measured at study models varied among different Angle's classes of malocclusions at the 1-month follow-up.

Class I crowding and CII.D1 without crowding or spacing subjects were relatively stable after treat-ment.

Class II.D2 ; Class I spacing and Class II.D1 spacing subjects were relatively prone to relapse post treatment.