Long-term durability of orthodontic mini-implants.

The current study aimed at examining surface and chemical composition changes of retrieved mini-implants after different periods of service as aids of anchorage for orthodontic patients. This study examined 72 retrieved orthodontic self-tapping and self-drilling mini-implants, 1.7 mm in diameter and 8 mm in length (OrthoEasy system, Forestadent, Pforzheim, Germany) from 36 adult orthodontic patients (18 men and 18 women, mean age = 23 years). The retrieved mini-implants were divided into 3 groups according to service period: 3-6 months (3M-6M) group, 6-12 months (6M-12M) group, and 12-24 months (12M-24M) group, with 24 mini-implants in each group. The control group (As Received) comprised of 24 unused mini-implants of the same type (AR group). All mini-implant heads and threaded bodies were examined for chemical characterization and topographical features by SEM-EDS. The average weight percentages for the following elements Ti, Al, and O2 were obtained and compared among the 4 groups. There was significant decrease in titanium content and deterioration for the surface properties for all parts of the mini-implants after being used inside patients' oral cavities for more than 6 months p < 0.05. The period of mini-implant service inside patients' oral cavities should not exceed 6 months.

The Prevalence of Root Resorption after Orthodontic Treatment in Patients Attending a University Hospital Dental Clinic.

INTRODUCTION: After orthodontic treatment, some teeth undergo external root resorption due to different factors, such as the root shape, oral habits, biological and genetic factor, gender, and age. Furthermore, extraction cases, long treatment duration, and the amount of force applied during the treatment might be related to root resorption. MATERIALS AND METHODS: Panoramic radiographs for 226 patients treated in the orthodontic department were screened. The lower first permanent molars, lower second premolars, and lower first premolars were measured in centimeters on a ruler using ImageJ System. Teeth were measured from the cusp tip to the cementoenamel junction (CEJ) and from the CEJ to the root apex, and then, the tooth was measured as a whole before and after the treatment. RESULTS: Multiple analysis of variance showed that there were no interactions between the root lengths of all teeth tested and either gender, treatment type, or treatment duration (P > 0.05). CONCLUSION: Based on the results of this study, no statistically significance relationship between external apical root resorption and gender, type of treatment, and treatment duration was found.