Objectives: The purpose of our study is to assess the correlation between chronological age, cervical vertebral maturation index and Demirjian index of the lower second molars and analyze if the correlation affected by intermaxillary sagittal malocclusion. Material and methods: 150 subjects were evaluated, with age range from 6-19 years. Skeletal maturation stages according to Baccetti method were determined in lateral cephalometric radiographs. Demirjian index for lower second molars were evaluated in panoramic x-ray. Digital lateral cephalograms and panoramic radiographs were performed by Vatech and they were analyzed and saved in DICOM format using dedicated software (Easydent version 4.1). Statistical analysis with IBM SPSS version 26 for Windows, Chicago, Illinois to assess the correlation between cervical vertebral maturation index and Demirjian index for lower second molars and intergroup comparison. Results: There is a strong positive correlation between chronological age, cervical vertebral maturation index and Demirjian index for lower second molars, with p < 0.000, Pearson correlation coefficient was from r = .847 to r = .883. The duration of prepubertal stage for class II subject was significantly longer. Whereas the actual peak of pubertal growth in class II subject was short, 3, 5 months. The overall period of growth modification raging from stage 2-4 of cervical vertebral maturation index was significantly longer in class III subjects. Conclusions: There is a strong correlation bewteen cervical vertebral maturation index and Demirjian index for lower second molars. The correlation is not affected by intermaxillary sagittal relationship, however in class II patients we have a shorter pubertal peak period and in class III there is a longer period of pubertal peak.

Objectives: This study aimed to compare changes in the lower dental arch after bonding two different shapes of Nickel titanium fixed retainers. The study was focused on whether the different shapes and sizes of retainers influence periodontal tissue response during one year of the post-treatment phase. Material and methods: Sixty subjects in total, of age (16-25), were randomly divided into two groups, every 30 subjects, upon finishing orthodontic treatment. Each group was divided into two subgroups according to growth factor (16-19) and (20_25) years old. First group FR was bonded Flat Nickel-titanium Retainer, thickness .010” x .029”, manufactured by Forestadent and to other 30 other subjects was bonded multistranded round Nickel -titanium retainer thickness ø 0.44mm/17”, manufactured by Dentaurum. Subjects had to come for checkups in 3,6,9, and 12 months, where four periodontal parameters were evaluated Plaque Index, Calculus Index, Gingival Index and Probing Depth. Results: There were statistically significant differences for the Plaque Index in favour of the Flat retainer. Also, the Gingival Index was higher in the Round retainer group but only after 12 months of retention. Pocket depth values increased in the first 3 months and then again showed the difference in the 12-month follow-up. Conclusions: Flat retainers showed less periodontal tissue response, lower Plaque Index, Gingival Index and less Pocket Depth compared to the Round retainers used in this study. But again, we found both types of fixed retainers initiate some periodontal response anyway.