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Aim To determine stresses generated in the posterior teeth region by two different self-ligating systems, 3M Unitek SmartClip and Damon Q Self-ligating brackets, using the finite element method (FEM). Methodology Computed tomography (CT) scan of maxilla was taken using Mimics software, and the Dicom data were imported into Hypermesh 13.0 software to convert it into a geometric model and then into FEM. Physical models of both the brackets were constructed and positioned on the teeth. Post archwire modeling, contact is defined between the bracket slot and 0.014” NiTi arch wire. The final assembled model was exported to ANSYS 12.1 for analysis, and 60 grams of load was applied at the ends of the arch wire. Results On using 0.014” CuNiTi in both the bracket systems, stresses generated on the root surface were found to be maximum on the first molar region, followed by the first premolar, second molar, canine, and second premolar regions. Comparison between the two bracket systems showed differences in the stresses generated, where higher stresses were generated at all regions in the Damon Q bracket system, except the inter-second premolar region. Conclusion Maximum stresses were observed with the 3M Unitek SmartClip bracket system at the second premolar cervical region when compared to the Damon Q system. In both the cortical bone and cancellous bone, maximum stresses were observed at the second premolar cervical in the Damon Q bracket system region.

BACKGROUND: The volumetric relationship between the tongue and the oral cavity is an important factor in tooth alignment and occlusion. The aim of this study was to evaluate the difference in tongue and airway volume in skeletal Class I and Class II malocclusion. MATERIALS AND METHODS: The CBCT data which comprised of 30 skeletal Class I and 30 skeletal Class II was stored in DICOM format. Tongue volume and airway volume was analyzed with the help of 3D dolphin software. Values obtained were subjected to statistical analysis with help of SPSS. RESULTS: Skeletal Class I pattern had more tongue volume with a mean of 45.32 mm3 than skeletal Class II pattern with mean value of 40.27mm3 with P value of

Background and Aim: One of the main reasons that patients seek orthodontic treatment is aesthetics. Unfortunately, treatment with fixed orthodontic appliances can at times increase the chances of developing white spot lesions on the surfaces of teeth, thus creating a new aesthetic issue for the patient. The prevalence of white spot lesions (WSL) reported after treatment varies from 2% to 97%, and these lesions can occur despite increased attention to hygiene. Hence the aim of this study was to assess the effect of Amine fluoride mouthwash in preventing white spot lesions during fixed orthodontic therapy. Materials and Methods: Study participants were randomly divided into two groups (Group A – experimental 25 patients and Group B – control 25 patients). The pre-intervention and post-intervention intra-oral digital photographs were analysed by using ImageJ software to assess the percentage of the facial surface affected on the teeth (10 maxillary teeth), which had white spot lesions. Results: The mean value of WSLs showed significant difference between the experimental and control groups. Mean values of WSL in the experimental group decreased from 2 to 1.54 with a mean difference of 0.46 after 6 months of follow-up which indicated that amine fluoride mouthwash was effective in preventing WSLs during fixed orthodontic treatment. Conclusion: WSLs scores were significantly reduced in patients who received the mouthwash when compared to patients who followed standard oral hygiene regimen with fluoridated toothpaste only. In clinical practice, amine fluoride mouthwash is an effective method for the prevention of WSLs during fixed orthodontic treatment.

Background. Although there are various intraoral and extraoral appliances for anchorage management in orthodontics, most fail to preserve the anchorage efficiently. Thus, there is a need for an appliance that can preserve anchorage in the sagittal, vertical, and transverse directions with good patience compliance and cost-effectiveness. This study compared the efficacy of butterfly arch and transpalatal arch (TPA) as an anchorage reinforcing unit during orthodontic space closure using a linear finite element model. Methods. A 3D model of the maxilla and associated structures was developed from CT images of an individual’s skull at a slice thickness of 1 mm. The magnitude of movements of anchor teeth in vertical, horizontal, and transverse directions was calculated in first premolar extraction cases during anterior retraction using a linear finite element model analysis and compared in two situations―butterfly arch and TPA attached to maxillary first molar for anchorage. Results. The anterior teeth had similar movements in the case of TPA and butterfly arch. There was more mesial and lingual movement in the first molars with TPA than in the butterfly arch, which had buccal but no mesial movement. The anterior teeth showed extrusion and the second premolars showed intrusion with TPA. Also, the von Mises stress and maximum principal stress were maximum with TPA at the cervical region of anterior and posterior teeth compared to the butterfly arch, where both stresses were uniformly distributed all over the teeth. Conclusion. A butterfly arch with its unique design, configuration, and biomechanical properties can be used as a device that can maintain the posterior anchorage efficiently

Background: Mandibular buccal shelf (MBS) offers good quality and quantity of bone for orthodontic bone screw (OBS) insertion. Despite several reports of treated patients, there are numerous variables in selecting the exact placement site for OBS placement in the MBS. There are also anatomical variations in this area which must be considered. Objectives: This study aims to measure and compare the MBS bone characteristics for OBS placement using cone beam computed tomography (CBCT) between two different facial types. Materials and Methods: Eighty CBCT samples were collected (40 samples of group A horizontal growers and 40 of group B vertical growers). Each CBCT image was reconstructed and oriented with CS 3D CBCT software. The cortical bone thickness, the slope of the MBS, and buccolingual inclination of mandibular second molar were measured and analysed. Result: Cortical bone thickness among horizontal growers was 5.23 ± 0.58 mm and among vertical growers was 4.85 ± 0.37 mm. The slope of MBS among horizontal growers was 60.83 ± 6.15 degrees and among vertical growers was 66.75 ± 6.27 degrees. In both the parameters there was a statistically significant difference between the groups. There was no significant difference between the groups for the buccolingual inclination of 2nd molar. Conclusion: Increased cortical bone thickness and the flatter slope of MBS at the 2nd molar region allows for easier placement of OBS in horizontal growers than in vertical growers.

Introduction: Micro-osteoperforation (MOP) and Low Level Laser Therapy (LLLT) are rapidly gaining popularity in clinical practice due to their proven success in accelerating tooth movement and acceptable patient compliance. However, literature shows an inconsistent and variable evidence of their iatrogenic effects on the root and pulp due to biological variations of the samples chosen by the previous studies. Aim: To evaluate and compare the rate of tooth movement, changes in amount of external root resorption and pulp vitality in teeth during en masse anterior retraction associated with MOP and LLLT using split mouth technique. Materials and Methods: This was a double blinded, single centre split mouth randomised clinical trial conducted at Faculty of Dental Sciences, MS Ramaiah University of Applied Sciences, Bangalore, Karnataka, India from March 2019 to October 2019. Total of 11 patients with bimaxillary dentoalveolar protrusion which required all four first premolar extractions were included in the study. Nickel Titanium (NiTi) closed coil springs were used for en masse retraction in upper and lower arches with force of 150 g per side. Root resorption of all anterior teeth was evaluated using Cone Beam Computed Tomography systems (CBCT) and pulp vitality was checked using cold test after four months. The data was entered in Microsoft excel and the Statistical Package for Social Sciences software (SPSS) version 18.5 (SPSS Inc, Chicago) software was used for data entry and statistical analysis. A p-value of less than 0.05 was considered as statistically significant. Results: Total of 11 patients in which 9 were females and 2 males aged between 18-30 years with mean age 19±4.21 year, participated in this trial. LLLT (4 mm) and MOP (4.05 mm) showed similar performance in acceleration of tooth compared to each other. The overall root resorption was more in the experimental groups (LLLT- 2.60 mm, MOP- 2.84 mm) compared to the allotted controls. However, the canine showed less root resorption in both the experimental groups compared to the control. The overall root resorption was similar in both the experimental groups. The canine in LLLT group (0.30 mm) showed less root resorption compared to canine in MOP group (0.59 mm). There was no change in the pulp vitality status in both the experimental groups and the control groups. Conclusion: The overall root resorption in a given quadrant increases with increased rate of tooth movement. The tooth which was subjected to acceleratory orthodontic technique showed less root resorption compared to control. The tooth subjected to LLLT showed less root resorption as compared to the tooth subjected to MOP.

Introduction: Knowledge of transverse dentofacial dimensions is crucial for accurate diagnosis and treatment planning. Periodontitis can alter the widths of the arches by causing pathological migration of teeth and the concurrent bone loss can affect the transverse width of the arches. Aim: To compare the transverse dentofacial widths in adults with skeletal class I and class II malocclusions with horizontal growth pattern and with mild to moderate periodontitis using Cone Beam Computed Tomography (CBCT). Materials and Methods: This retrospective observational study was conducted in Department of Orthodontics, Faculty of Dental Sciences, Ramaiah University of Applied Sciences, Bengaluru, Karnataka, India, from January 2019 to January 2021. Total 96 CBCT samples (48 skeletal Class I, 48 skeletal Class II) of patients between age group of 25-35 years, patients having mild to moderate periodontitis based on bone loss seen on CBCT and patients having a horizontal growth pattern with the angle between sella-nasion and mandibular plane less than 32° were included in the study. Transverse dentofacial measurements were made on the coronal plane of the CBCT scans. Data were analysed using Statistical Package for Social Sciences (SPSS) version 20. Chi-square test and Student’s t-test were used to compare age, linear measurements and angular measurements between the skeletal class I and skeletal Class II groups. A p-value of

Objective: The aim of the study was to analyze the displacement and stress pattern in periodontal ligament (PDL) of palatally impacted canines (PIC) lateral incisors (LI) and first premolars (FP) adjacent to the impacted teeth when different magnitudes of orthodontic extrusion forces were applied along with variation in the inclination of the impacted teeth. Methodology: A three-dimensional finite element model of a maxilla containing a palatally impacted canine was made with three different inclinations of the palatally impacted canine (model one, model two, and model three). Forces of 50, 70, and 100 g were loaded on the impacted tooth. Results: There was steady increase in the initial rate of displacement in the three teeth when the magnitude of the force that was applied on to the PIC increased. The initial rate of displacement was more in the FP tooth as compared to LI and the impacted teeth. The von Mises stress on the PDL varied along with the variation in the inclination of the impacted canine. Conclusion: The study showed that there was variation in the displacement and the stress distribution in the impacted canine when it was placed in different angulations. The rate of displacement of the impacted teeth reduced when the crown of the palatally impacted canines (PIC) was inclined more mesial. The use of minimal forces is ideal to extrude the impacted canines as observed from the study that the PDL stress increases with increase in the magnitude of force.

Introduction: Application of orthodontic forces to a tooth is characterised by extensive macroscopic and microscopic changes during remodelling which occurs in the Periodontal Ligament (PDL), alveolar bone and gingiva. This occurs mainly due to the local stresses and strains subjected on the supporting tissues. As direct measurement of these parameters is almost impossible, Finite Element Method (FEM) is an effective method for calculating stress and strain distribution on the alveolar bone. Aim: To assess the stress and strain distribution in the cortical and cancellous bone around maxillary central incisors during the process of diastema closure with a constant force using FEM. Materials and Methods: A three-dimensional computer model of anterior segment of the maxilla simulated from a CBCT scan was reproduced using MIMICS software and they had varying width of midline diastema of 4 mm, 3 mm and 2 mm. Each tooth was designed with a bracket on the labial surface and a 0.019×0.025 orthodontic stainless steel wire. A 1.5 N of force was applied on the labial surface of the brackets. Stresses and strains around the two central incisors on the alveolar bone were calculated. Results: In the cortical bone, maximum compressive stress (Von-Mises stress) was concentrated at the mesial side and tensile stress (principle stress) on the distal side near the cervical region of the central incisors in all the 3 models. Maximum stress was seen in the 2mm midline diastema model. In the cancellous bone, both these stresses were concentrated along the roots of central incisor cavity more towards the middle of the tooth in all the 3 models. In the longitudinal section, stress and strain was more concentrated at the cervical region gradually decreasing as they reached apex of the tooth in cortical bone and in the cancellous bone maximum stress was observed in the middle third. Conclusion: Stresses in the cortical bone increases when the diastema gap is small while strain in cancellous bone increases when the midline diastema width is large. The stresses in cancellous bone remain constant in all the 3 models. Graphically the strains were more concentrated near cervical region of the teeth in both the cortical and in cancellous bone maximum stress was observed in the middle third.

Introduction: Class III malocclusion exists when the mandibular molar occludes mesial to the maxillary molar as a result of a skeletal discrepancy i.e., normal maxilla and protruded mandible, retruded maxilla and a normal mandible or a retruded maxilla and a protruded mandible, concomitant with or without a dental discrepancy, or due to the functional shift of the mandible. Orthopaedic and functional appliances like chin cup, Functional Regulator 3 (FR3), Class III activator, reverse twin block etc., can be used to treat Class III malocclusion. Reverse twin block is a patient friendly appliance, presenting acceptable clinical results. Stresses are the key to remodelling of the alveolar and craniofacial bones incident to functional and orthopaedic forces, which can be elucidated via Finite Element Analysis (FEA). Literature lacks studies pertaining to biomechanical evidence on the functional appliance effect in Class III malocclusion. Aim: To evaluate the patterns of stress distribution and displacement in the maxilla and the mandible with the reverse twin block appliance, in four groups with combinations of bite force of 107 N and without bite force, along with passive tension of 1.27 N and 1.47 N for 2 mm and 4 mm interincisal clearance respectively, through FEA. Materials and Methods: A three dimensional finite element model was developed from the Cone Beam Computed Tomography (CBCT) images of a patient with Class III malocclusion using Hypermesh 13.0 software. The model simulated forces of reverse twin block appliance with 2 mm and 4 mm interincisal clearance with and without maximum bite force of 107 N. Stress distribution and displacement in the region of glenoid fossa, maxillary tuberosity, Anterior Nasal Spine (ANS), neck of the condyle and gonial region was studied. Results: Maximum stresses were observed in the glenoid fossa and the neck of the condyle. Stress generation was subsequently more with 4 mm interincisal clearance group. The displacement resulting from reverse twin block was mainly dentoalveolar. Maxillary incisors displaced more than the mandibular incisors. The mandible displaced more in the forward and downward direction. Conclusion: The treatment outcomes with reverse twin block appliance previously assessed by means of cephalometric studies were validated with insight of stresses induced at different regions of the maxilla and the mandible via the finite element methodology. The forces exerted by this appliance directed the stresses more towards the dentoalveolar region. Stresses were more profound when the passive tension was concurrent with the bite force.

Introduction: Cephalometry has many limitations of which radiation exposure is most important. Hence, there is a need to resort to other safer methods which could give equal if not better results. Aim: The purpose of this study was to compare and correlate the craniofacial measurements obtained from cephalometric radiographs and analogous measurements from standardized facial profile photographs in skeletal class II cases. Materials and Methods: A total of 30 lateral cephalograms and profile photographs of patients exhibiting skeletal class II malocclusion, in the age group of 19-25 years of age, were examined in this study using Dolphin software (version 11.8). A standardized protocol was followed for all the lateral cephalograms and photographs. A total of 15 parameters were studied in this study out of which seven were angular and eight were linear parameters. Angular parameters included Frankfort Mandibular Plane Angle (FMA), Mandibular PlaneOcclusal Plane (MP-OP) angle, Occlusal Plane (OP) angle, gonial angle, ANB angle, facial angle and convexity whereas linear parameters included Anterior Facial Height (AFH), Ramal height, Posterior Facial Height: Anterior Facial Height (PFH/ AFH), convexity (in mm), Nasion perpendicular- Point A, Nasion perpendicular- Pogonion, Witts and Mandibular body length. All these parameters were digitised on both the cephalogram and photographs and were compared using one sample-2 tailed t-test, Pearson correlation coefficient. Bland-Altman Plot was considered to find comparison between the measurements from photographs and cephalograms in skeletal class II patients. Results: On comparing the angular cephalometric and photographic variables for the skeletal class II subjects we found the cephalometric parameters like FMA, MP-OP angle, OP, gonial angle, convexity (in degrees) to have an insignificant difference compared to the analogous photographic measurements. On comparing the linear cephalometric and photographic variables, it was found that all the cephalometric parameters like AFH, ramal height, PFH/AFH, N perp-Point A, N perp-Poghad a good relationship with the analogous photographic measurements. Conclusion: The photographic method can be considered as a repeatable and reproducible method if a homogeneous protocol is followed. Thus, photographic measurements may reflect to be a rational and practical diagnostic substitute to measurements obtained from cephalograms in Class II malocclusion subjects.