Aim: The study aimed to evaluate the shear bond strength (SBS) of metal brackets and adhesive properties of bonded irradiated and non-irradiated teeth. Methods: Sixty-six extracted premolar samples were randomly divided into three groups—(a) Control group consisting of 22 non-irradiated, non-aged teeth (Group 1), (b) 22 non-irradiated, aged samples (Group 2) and (c) 22 irradiated, aged samples (Group 3). Irradiation was done using gamma irradiation with a fractionated dose of 60 Gy for 5 consecutive days per week over 6 weeks. Metal brackets were bonded on all samples with light cure adhesive and subjected to SBS test using universal testing machine. The samples were assessed under the scanning electron microscope to check for the adhesive remnant index (ARI) and tag depth. Results: There was a statistically significant decrease in the mean SBS of the irradiated samples compared to the non-irradiated teeth. The non-irradiated, aged samples showed a majority of ARI scoring 1 and 2. Whereas, the irradiated samples showed ARI scoring 2 and 3. Approximately, 77·3% of the non-irradiated samples showed no adhesive present on the tooth surface, and 27·2% of the irradiated samples had more than 50% adhesive present on the enamel surface. Conclusion: There is a statistically significant decrease in SBS of irradiated enamel compared to that of non-irradiated teeth. However, the SBS observed in the three groups was well above the ideal SBS for orthodontic bonding, that is, 5·6–6·8 MPa. The adhesive remnant was found on all samples of the irradiated group. Deeper adhesive resin tags were found in the irradiated group in the resin–enamel interface.

Aims: To assess the changes in the oropharyngeal airway (OAW) dimensions in individuals with retrognathic mandible treated with Forsus FRD and Twin Block appliance to correct the skeletal Class II mal relationship. Methodology: 40 individuals, with Class II skeletal pattern were selected as per inclusion criteria. Pre-treatment lateral cephalograms and hand wrist radiographs were obtained and analyzed. Group 1 with 20 individuals were treated with Forsus FRD and Group 2 with 20 individuals were treated with conventional Twin Block Appliance. Post treatment records were taken after the Class I molar relationship had been obtained. Pre and post treatment cephalograms were compared and analyzed. The data obtained was statistically evaluated using paired t test and unpaired t test. Results: On comparison of pre-treatment and post-treatment cephalograms, increase in Oropharyngeal Airway (OAW) measurements, such as Superior posterior airway space (SPAS), Middle airway space (MAS) and Inferior airway space (IAS) was very highly significant. Conclusion: Our results suggest the existence of a relationship between functional-orthopaedic treatment and increases in OAW dimensions in skeletal Class II growing subjects.

Objective: To compare and evaluate the cephalometric hard and soft tissue changes of mandible after orthodontic treatment with and without extraction of four first premolar. Methodology: 60 individuals with Class I skeletal pattern were selected as per inclusion criteria. They were divided into two groups: 30 in the extraction group and 30 in the non-extraction group. Each group consists of 15 males and 15 females. Pre-treatment and post-treatment lateral cephalograms of the selected subjects were obtained, analysed and compared to assess the changes might have occurred. Descriptive statistics of the explanatory and outcome variables were calculated by mean and standard deviation for quantitative variables. Paired t test was applied to check the statistical difference of pre-treatment and post-treatment cephalometric parameters within the group (Extraction and non-extraction). Unpaired t test was used to check the statistical difference between extraction and non-extraction groups. The level of significance is set at 5%. Results: B point moved backward with lower incisor retraction. N-A-Pog shows a statistically significant decrease in the extraction group (P=0.003). B-NP shows a statistically significant decrease in extraction group (P=0.001). N- A’-Pog’ shows a statistically significant increase in non-extraction group (P=0.046). Soft tissue thickness in chin increases in extraction group and decreases in non-extraction group. Conclusion: The results indicate that premolar extraction will have a flattening effect on the midface. With proper diagnosis and treatment planning, premolar extractions have high potential to improve the facial profile.