Computed Tomographic Evaluation of Buccal Shelf Dimensions in South Indian Patients With Sagittal Skeletal Class III Malocclusion: A Retrospective Study.

Background Computed tomographic evaluation of mandibular buccal shelf region in skeletal class III malocclusion cone beam computed tomography (CBCT) studies have been reported to have great alteration in the thickness of mandibular buccal shelf region owing to the different growth patterns and ethnic variations. The aim of this study was to determine the total and cortical bone thickness in the mandibular buccal shelf (MBS) region for extra-alveolar mini-screw placement in South Indian patients with sagittal skeletal class III malocclusion. Material and methods This retrospective computed tomographic study consisted of archived files of the Dravidian population with class III skeletal base that met the eligibility criteria. The total bone and cortical bone thickness of the buccal shelf regions were evaluated in relation to three anatomical sites at various depths and angulations. One-way ANOVA and Tukey honestly significant difference (HSD) post hoc tests were used for statistical analysis. Pearson correlation coefficient was performed to compare if any relation existed between bone thickness and the growth pattern. Results The maximum bone thickness in the buccal shelf region in our study was found at the distal portion of the second molar root, 8-12 mm from its cementoenamel junction (CEJ) and at 30-45 ° angulation (p-value<0.005). There was a positive correlation between the hypo-divergent growth pattern and the thickness of the bone. Conclusion Based on the sites recorded, the preferred site for mini screw placement in Class III patients is the distobuccal cusp region with respect to the second molar at a depth of 8-12 mm and at angulation of 30-45 °. There was a moderate correlation with hypo-divergent growth patterns, suggestive of a wider and thicker mandibular buccal shelf region in these subjects.

An evaluation of the accuracy of bracket positioning with and without loupes using 3Shape Ortho Analyzer software.

Objective: The accuracy of bracket positioning is very important for successful orthodontic treatment. Precisely placed brackets aid in the enhancement of treatment outcomes. The aim of the present study was to evaluate the accuracy of bracket positioning with and without dental loupes and compare this method with bracket positioning achieved using the 3Shape Ortho Analyzer. Methods: A single blinded, split-mouth, randomized and controlled trial was conducted in the Department of Orthodontics. Three-dimensional (3D) scanned models of the maxillary arches of the subjects were obtained using 3Shape Ortho Analyzer software and virtual setups were prepared. Right and left quadrants of the maxillary arch of the 10 subjects were randomly allocated for manual bonding with loupes or without loupes. The manually bonded maxillary arch was then scanned and 3D models were obtained; these were then compared with bracket positioning achieved with the 3Shape Ortho Analyzer. In the two quadrants, deviations in the position of each bonded bracket was compared in the mesio-gingival, disto-gingival, mesio-occlusal, disto-occlusal, distal and mesial areas and then further compared with the virtual set up. Finally, bracket positioning errors were measured. Results: An independent sample t-test was performed to compare both the area-wise and teeth-wise mean error in bracket positioning with loupes and without loupes which showed no statistically significant difference. Conclusion: There was no significant difference in bracket positioning with or without loupes. The results of this current study showed that bracket positioning can be performed with loupes or without loupes.

Reliability of Frankfort Horizontal Plane with True Horizontal Plane in Cephalometric Measurements.

INTRODUCTION: The purpose of the study is to determine reliability of true horizontal (TH) plane with Frankfort horizontal (FH) plane in cephalometric measurements. MATERIALS AND METHODS: One hundred lateral cephalograms were collected and traced using FACAD software, all cephalometric measurements which included FH plane as reference planes were used in this study. Cephalometric tracing was done with FH plane as reference plane and another set of measurements with TH plane as reference plane was done. Statistical tests were done using independent sample t-test (p <0.05). RESULTS: Results of an independent t-test revealed a statistically insignificant difference that was observed for all the parameters assessed (p <0.05). Both angular and linear measurements showed an insignificant difference between FH and TH. CONCLUSION: Within the limitations of the study, the results show that the FH plane is closest and as reliable as the TH plane. The variation of FH was least for all the parameters assessed.

ATM technique - a novel radiographic technique to assess the position of buccal shelf implants.

OBJECTIVES: Success of the buccal shelf implants depends on its proper placement. Radiographic techniques like cone beam computed tomography (CBCT), posteroanterior cephalogram (PA cephalogram) have been used to evaluate the position of buccal shelf implant placement. However, these techniques have disadvantages like increased radiation exposure, metal artifact, less availability in dental offices and are more expensive.The aim of Arvind's Trans Mandibular (ATM) technique is to overcome this drawback by using an intraoral periapical radiograph (IOPA) film or radiovisiography (RVG) sensor to assess the post-operative placement of buccal shelf implants. METHODS: Radiographs were taken for four patients after the placement of buccal shelf implants. The IOPA sensor was placed beneath the lower border of the mandible using this modified extraoral technique to assess the position of the buccal shelf implants in relation to the adjacent molars. The findings from the IOPA image were verified with CBCT images. RESULTS: The radiographic images taken using ATM technique were compared with the gold-standard CBCT technique. The ATM technique was able to accurately assess the postoperative buccolingual position of the implant with respect to the roots of molars in all the four cases. The proximity of the implant to the roots of the molar can be clearly visualized in all the cases. CONCLUSIONS: ATM is a novel radiographic technique using IOPA radiographic film or RVG sensor to assess the post-operative buccolingual placement of buccal shelf implants in relation to lower molar roots.

Evaluation of accuracy and reliability of OneCeph digital cephalometric analysis in comparison with manual cephalometric analysis-a cross-sectional study.

INTRODUCTION: Lateral cephalometric analysis continues to be one of the gold standard diagnostic aids in orthodontics, with various software available to enhance this. AIM: This study was done to evaluate the accuracy and reliability of linear and angular measurements obtained from OneCeph digital cephalometric tracing and manual tracings in lateral cephalometry. METHODOLOGY: This is a cross-sectional study done on twenty pre-treatment lateral cephalometric radiographs of subjects who reported to the postgraduate orthodontic clinic for orthodontic treatment over one month. Cephalometric tracings were done using OneCeph digital software and manual tracing method to evaluate nine parameters of Steiner's cephalometric analysis. An Independent T-sample test was done between the mean values of manual and OneCeph tracing. Intra operator reliability was evaluated by paired T-test after a week. RESULTS: No significant statistical difference was observed as the p-value was greater than 0.05 for all the parameters in the two groups. CONCLUSION: The reliability and accuracy of OneCeph software application was found to be at par with manual cephalometric tracing.

CBCT comparison of buccal shelf bone thickness in adult Dravidian population at various sites, depths and angulation - A retrospective study.

INTRODUCTION: It is important to understand the variations in the bone thickness of the buccal shelf region among different ethnic groups, as these variations will influence the placement and success of the buccal shelf mini-screw. OBJECTIVES: The primary objective was to analyse the total buccal bone and cortical bone thickness of the mandibular buccal shelf region (MBS) at various depths, mesiodistal positions and angulations in Dravidian population and to find the best site for insertion of buccal shelf mini-implant. MATERIAL AND METHODS: This was a retrospective study done on 30 cone-beam computed tomography samples collected from 30 subjects, aged 16 to 25 years and of Dravidian origin, who reported for orthodontic treatment. The total bone and cortical bone thicknesses of the buccal shelf regions were evaluated in relation to the Disto-Buccal cusp of 1st Molar (DB1M), Mesio-Buccal cusp of 1st Molar (MB1M), and Disto-Buccal cusp of 2nd Molar (DB2M) at the depths of 4mm, 8mm and 12mm from cemento-enamel junction (CEJ). The total bone thickness and the clearance from the root and cortical bone thickness were assessed at angulations of 30, 45 and 60 degrees from 5mm below the root apex. ANOVA and Post Hoc tests were done to compare the bone thickness measurements. Kappa statistics was done to assess the intraobserver reliability. Pearson's correlation test was done to find the correlation between growth pattern and thickness of the bone. RESULTS: The mean age group of the included sample was 20.5 years. Maximum total bone thickness was observed at a depth of 8mm in relation to the MB2M (6.41±0.29mm) and 12mm in relation to the DB2M 6.56±0.28mm and the P value was 0.000. Maximum bone thickness was present in the DB2M at 30° followed by DB2M 45° of 11.42±0.35mm and 10.89±0.3mm and the P value was 0.000. The maximum clearance from the root was observed at 30° and 45° in the DB2M with 5.35±0.2mm and 5.18±0.27mm, the P value was 0.014 when comparing angulation 30 and 45°. The DB2M had a cortical bone thickness of 2.97±0.15mm and 2.8±0.2mm at 45° and 60° and was statistically significant. CONCLUSIONS: The insertion site with optimal bone quantity was observed in relation to the buccal aspect of distobuccal cusp of 2nd molar at depth of 8mm or greater with a preferred angulation of 30-45° to have adequate clearance from the molar tooth roots and to penetrate a region of cortical bone of minimum 2mm.

A Comparison of Craniofacial Characteristics between Two Different Adult Populations with Class II Malocclusion-A Cross-Sectional Retrospective Study.

The dental, skeletal, and soft-tissue characteristics of a particular malocclusion can differ based on ethnicity, race, age, sex and geographical location with Class II malocclusion being one of the most prevalent malocclusions encountered in orthodontic clinical practice. The broad understanding of the characteristics of vertical skeletal and dental parameters in patients with Class II malocclusion can help clinicians to identify patterns and variations in the expression of this phenotype for better treatment outcomes. Hence, we compared the craniofacial characteristics of skeletal and dental Class II malocclusion traits from Indian and Vietnamese individuals to analyze the vertical skeletal and dental patterns in both population groups. The sample comprised of lateral cephalograms from 100 young adults with Class II malocclusion, of which fifty (25 males and 25 females) were from South India and the other 50 age- and sex-matched adults from Vietnam. The lateral cephalometric radiographs were digitized into anonymous image files and were traced and assessed for 16 vertical skeletal and dental parameters. The ANB angle was greater in males (+1.4 deg; p < 0.001) and females (+1.9 deg; p < 0.001) in the South Indian population. The Vietnamese males had a larger mandibular plane angle, articular angle, anterior facial height and lower anterior facial height compared to the Indian males. The Vietnamese females had larger mandibular plane and articular angles compared to the Indian females. The skeletal class II malocclusion was more severe in the South Indian compared to the Vietnamese adults. The Vietnamese sample showed a generalized tendency towards a more vertical skeletal growth pattern and in males this pattern seemed to be due to the dentoalveolar component. The Vietnamese females showed a tendency towards a vertical growth pattern, but without apparent contribution by the dentoalveolar component.

Evaluation of the distortion of photographs using various focal lengths.

It is of interest to evaluate the distortion of intraoral frontal photographs using various focal lengths. Intra-oral frontal view pictures of 20 subjects were taken using a standard 18-55mm lens of a DSLR camera at three different focal lengths (18mm, 35mm, 55mm). 52 experienced orthodontists were chosen and they were asked to assess the photographs and choose the one with the least amount of distortion. Majority of the orthodontists selected the frontal photograph taken at a focal length of 35mm as the best photo with the least distortion among the three photographs. The photos taken at a focal length of 35 mm showed the least amount of distortion.

Evaluating the Effect of Denosumab in Preventing Anchorage Loss: A Split-mouth Randomized Controlled Trial.

AIM: The trial was focused on assessing the effect of Denosumab in preventing anchorage loss during en-masse anterior retraction and evaluating its effect on the retraction. MATERIALS AND METHODS: This was a split-mouth randomized controlled trial. Ten subjects were randomly allocated with equal probability for Denosumab and control interventions in the contralateral quadrants using computer-generated randomization sequence. During the start of retraction, Denosumab (5 mg/0.2 mL) and injectable sterile water were administered locally on the intervention and control sides, respectively. Lateral cephalograms taken during the start of retraction and later in the 3rd and 6th months into retraction were used to evaluate anchorage loss and retraction. Independent sample t-test and Mann-Whitney U test compared anchorage loss and retraction between the two groups in the maxilla and mandible. Paired t-test and Wilcoxon signed-rank test assessed the anchorage loss and retraction during the first and the second 3 months of retraction. RESULTS: In the maxilla, Denosumab was effective in preventing anchorage loss with a p-value of 0.001 whereas it was not effective in the mandible (p-value-0.172). A significant reduction in anchorage loss was observed with Denosumab in the second 3 months of retraction compared to the first 3 months. There was no significant difference in the retraction among both groups. CONCLUSION: Denosumab was effective in minimizing the anchorage loss in the maxilla without affecting the anterior retraction. CLINICAL SIGNIFICANCE: Denosumab can be effectively used for reinforcing anchorage in the maxilla during en-masse anterior retraction.

Palatal plane inclination on vertical growth pattern among Indians.

The skeletal discrepancies in the vertical dimensions can either lead to a long face or a short face. The palatal plane inclination is one such contributing factor. The study sample comprised of 15 lateral cephalograms collected between the time period of June 2019 - March 2020 with 5 cephalograms belonging to skeletal Class I, II and III respectively. The inclination angle and mandibular plane angle were measured using the FACAD software. The obtained results were tabulated and statistically analysed using Pearson's correlation test to determine the correlation between the two variables. There was a statistically significant negative correlation between the skeletal malocclusions with a p value of 0.011. Thus, palatal plane inclination is not a major contributing factor for vertical growth pattern and it is suggestive of a multifactorial influence.

FSA Angle: A Soft Tissue Approach for Assessing Sagittal Skeletal Discrepancy.

INTRODUCTION: Lateral cephalograms are taken as a diagnostic aid for the evaluation of the anteroposterior relationships. The assessment of anteroposterior soft tissue relationships is by using skeletal points and cranial reference planes. The anteroposterior relationships are, however, clinically affected by soft tissue structures. In this pilot study, we aim to assess the anteroposterior relationships based on soft tissue landmarks. MATERIALS AND METHODS: Lateral cephalograms were collected from 100 patients and evaluated on Facad software. The subject consisted of a mean age of 20 ± 7 years. Fifty-four cephalograms selected were used to perform the analysis. A new angle FSA was measured based on soft tissue landmarks. A new plane used for this analysis is the SA plane. Using this angle, we classified the cephalograms as class I, II, and III. RESULTS: There is a statistically significant value to differentiate the profile of patients using the FSA angle. Thus, this new angle is created to determine the anteroposterior soft tissue relationship using soft tissue landmarks on a cephalometric analysis and from our data, the value was 81 ± 7.57° for class 1 patients that is consistent with the previous studies which evaluate sagittal skeletal relationships. CONCLUSION: There are various difficulties and errors in the previous analysis that is used to determine the anteroposterior jaw relations. Skeletal landmarks have been used previously and most of these points are not stable points. Thus, this new analysis that will be using soft tissue landmarks can be used to differentiate in the various profiles of patients with different malocclusions. HOW TO CITE THIS ARTICLE: Sreenivasagan S, Sivakumar A. FSA Angle: A Soft Tissue Approach for Assessing Sagittal Skeletal Discrepancy. Int J Clin Pediatr Dent 2021;14(S-1):S54-S56.

Comparison of accuracy of mesiodistal tooth measurements made in conventional study models and digital models obtained from intraoral scan and desktop scan of study models.

OBJECTIVE: To compare the measured values obtained from the plaster model, digital models created by scanning the plaster models and direct intraoral scanning with the values obtained from direct intraoral measurements. DESIGN: This was a prospective clinical study. SETTING: The study was conducted in Department of Orthodontics, Saveetha Dental College and Hospital, Tamil Nadu, India. PARTICIPANTS: Ten patients before the start of orthodontic treatment were selected for the study. METHODS: A computer-aided design and manufacturing (CAD-CAM) system is an advanced technology that is being adopted in the field of orthodontics for diagnosis, treatment planning and documentation of patient records. Mesiodistal tooth width measurements of first premolars, canines, lateral incisors and central incisors, and transverse width measurement from mesial pit of right first premolar to mesial pit of left first premolar in both maxilla and mandible were obtained from direct intraoral measurement (gold standard), study model obtained from alginate impression, intraoral scanned image, and desktop scanned image of the study model. Descriptive statistics and ANOVA was performed to find the difference in mean among the groups. RESULTS: A P value > 0.05 was obtained in ANOVA indicating that there is no statistically significant difference in the measurements obtained by either of the methods. CONCLUSION: Conventional stone models and digital models obtained from intraoral scan and desktop scanning of plaster models are clinically reliable as the variations in measurements obtained from these methods were clinically negligible.

Comparison of bone thickness in infrazygomatic crest area at various miniscrew insertion angles in Dravidian population - A cone beam computed tomography study.

INTRODUCTION: Infrazygomatic crest miniscrews are an important advancement in the field of orthodontics for anchorage reinforcement. The size of the miniscrews and the site of placement depend on the bone thickness in the infazygomatic crest area. The bone morphology and the thickness vary among different ethnicities of population. OBJECTIVES: To assess the bone thickness in the infrazygomatic crest area around the distobuccal root of the maxillary first molar using cone beam computed tomography and determine the best possible site and angulation for the placement of the miniscrew. Therefore, to determine the size of the implant that will suit the Dravidian population. METHODS: The infrazygomatic crest bone thickness was evaluated on 10 patients using cone beam computed tomography. The measurements were made along the distobuccal root of maxillary first molar at different angulations ranging from 75° to 40° to the occlusal surface of the molar. RESULTS: The infrazygomatic crest bone thickness was of 4.5mm to 9mm for the Dravidian population, when measured at an angle of 40° to 75° to the maxillary first molar occlusal plane and of 11 to 17mm above the occlusal plane. Student t-test (confidence interval 95%) was done to determine gender variation and compare the bone thickness of right and left side. ANOVA and post-hoc test were done to find the statistical difference between the bone thickness measured at different insertion angles. CONCLUSIONS: The best possible site for miniscrew insertion is 12 to 17mm above the occlusal plane at an angle of 65° to 70°, with no injury to the adjacent anatomical structures, no mucosal irritation and adequate stability for the miniscrew. The ideal infrazygomatic crest screw length for Dravidian population is 9 to 11mm.