Stress distribution and displacement with four different types of MARPE on craniofacial complex: A three-dimensional finite element analysis.

BACKGROUND: Various designs of mini-implants assisted rapid palatal expander (MARPE) appliances can impact treatment effectiveness through their biomechanical effects. The purpose of the study was to study the stress distribution and displacement with four different designs of the MARPE appliance on the craniofacial complex. METHODS: A 3D finite element model of the craniofacial complex was created from CBCT DICOM data, comprising four distinct groups. Each group consisted of one 4-hole expansion screw positioned between the second premolar and first molar in all models. Group 1 used four single-cortical mini-implants (1.5×8mm) engaging only the palatal cortex. Group 2 employed four mini-implants (1.5×11mm) engaging both the palatal and nasal cortices. Group 3 had monocortical implants on the palatal slopes, while Group 4 was similar to group 3 with implants in the acrylic wings. Comparisons between groups were made for anchorage (groups 1 and 2), mini-implant position (groups 1 and 3) and surface effect (groups 3 and 4). Von Mises stresses and displacements at various skeletal and dental points were evaluated using ANSYS software. RESULTS: The highest stresses were observed in the maxillary, pterygoid and zygomatic bones, as well as in the mid- palatal suture in all four groups. Downward and forward rotation of the craniofacial complex was noted. Group 2 showed greater skeletal expansion than group 1. Among groups 1 and 3, group 3 showed a better stress distribution. Group 4 showed less dentoalveolar rotation than group 3. CONCLUSIONS: The MARPE appliances had an impact on the craniofacial complex with stresses on the mid-palatal suture, maxillary bone, pterygoid bones and anterior teeth. Clockwise rotation of the maxilla, zygomatic bones and dentition was noted, while the pterygoid bones and pterygoid suture were displaced backwards. MARPE with bicortical anchorage produces better skeletal expansion. Placing implants on the palatal slopes with acrylic wings results in better skeletal expansion with less clockwise rotation of the dentition.

Association, diagnostic accuracy and optimal threshold of salivary IGF-1 and vitamin DBP levels for estimation of pubertal growth spurt: A cross sectional study.

AIM: To determine the association of salivary IGF-1 and vitamin D Binding Protein with cervical vertebral maturation index (CVMI) across the pubertal stages and to determine the diagnostic accuracy and optimal threshold of these biomarkers for estimation of pubertal growth. DESIGN: Cross-sectional observational study. SETTING: Material and methods. All patients in the age group of 8-23 years from the Outpatient Department of Orthodontics and Dentofacial orthopaedics, between the period of July 2020 to December 2020 meeting the eligibility criteria were included. Lateral cephalograms obtained from the patients were divided into pre pubertal, pubertal & post pubertal groups based on CVMI by Baccetti et al. Unstimulated whole saliva was collected by a swab-based method & analyzed with ELISA. RESULTS: Ninety-four participants were divided in three stages: prebubertal (30), pubertal (33), post pubertal (31). A significant difference was observed in the salivary IGF-1 & DBP across the three stages. Post-hoc test revealed significantly higher mean salivary IGF-1 & DBP in pubertal group than in pre & post-pubertal group. Receiver operator characteristic curve revealed excellent diagnostic accuracy for salivary IGF-1with areas under the curve (AUC) of 0.962, satisfactory for vitamin DBP with AUC of 0.831 and poor diagnostic accuracy for age with AUC of 0.536. Youden index revealed the optimal threshold to be 3.96ng/ml and 124.13pg/ml for salivary IGF-1 and vitamin DBP respectively. CONCLUSION: The levels of Salivary IGF-1 and Vitamin DBP increased during C3 and C4 stages. Compared to vitamin DBP diagnostic accuracy of salivary IGF-1 was excellent and an optimal threshold of 3.96ng/ml can be utilized to distinguish pubertal & non-pubertal participants.

Effects of different force directions of intra-oral skeletally anchored maxillary protraction on craniomaxillofacial complex, in Class III malocclusion: a 3D finite element analysis.

INTRODUCTION: The intra-oral skeletally anchored maxillary protraction (I-SAMP) has been found to be an effective treatment for skeletal Class III malocclusion. OBJECTIVE: This in-silico study explored the influence of different force directions of intra-oral skeletally anchored Class III elastics on the changes in craniomaxillofacial complex, using finite element analysis. METHODS: A 3-dimensional (3D) finite element model of the craniomaxillofacial bones including circummaxillary sutures was constructed with high biological resemblance. A 3D assembly of four miniplates was designed and fixed on the maxilla and mandible of the finite element model. The model was applied with 250g/force at the miniplates at three angulations (10°, 20°, and 30°) from the occlusal plane, to measure stress and displacement by using the ANSYS software. RESULTS: The zygomaticotemporal, zygomaticomaxillary, and sphenozygomatic sutures played significant roles in the forward displacement and counterclockwise rotation of maxilla and zygoma, irrespective of the angulation of load application. The displacements and rotations of the zygomatico-maxillary complex decreased gradually with an increase in the angle of load application between miniplates from 10° to 30°. The mandible showed negligible displacement, with clockwise rotation. CONCLUSIONS: The treatment effects of I-SAMP were corroborated, with insight of displacement patterns and sutures involved, which were lacking in the previously conducted 2D and 3D imaging studies. The prescribed angulation of skeletally anchored Class III elastics should be as low as possible, since the displacement of zygomatico-maxillary complex increases with the decrease in angulation of the elastics.

Effects of different force directions of intra-oral skeletally anchored maxillary protraction on craniomaxillofacial complex, in Class III malocclusion: a 3D finite element analysis

ABSTRACT Introduction: The intra-oral skeletally anchored maxillary protraction (I-SAMP) has been found to be an effective treatment for skeletal Class III malocclusion. Objective: This in-silico study explored the influence of different force directions of intra-oral skeletally anchored Class III elastics on the changes in craniomaxillofacial complex, using finite element analysis. Methods: A 3-dimensional (3D) finite element model of the craniomaxillofacial bones including circummaxillary sutures was constructed with high biological resemblance. A 3D assembly of four miniplates was designed and fixed on the maxilla and mandible of the finite element model. The model was applied with 250g/force at the miniplates at three angulations (10°, 20°, and 30°) from the occlusal plane, to measure stress and displacement by using the ANSYS software. Results: The zygomaticotemporal, zygomaticomaxillary, and sphenozygomatic sutures played significant roles in the forward displacement and counterclockwise rotation of maxilla and zygoma, irrespective of the angulation of load application. The displacements and rotations of the zygomatico-maxillary complex decreased gradually with an increase in the angle of load application between miniplates from 10° to 30°. The mandible showed negligible displacement, with clockwise rotation. Conclusions: The treatment effects of I-SAMP were corroborated, with insight of displacement patterns and sutures involved, which were lacking in the previously conducted 2D and 3D imaging studies. The prescribed angulation of skeletally anchored Class III elastics should be as low as possible, since the displacement of zygomatico-maxillary complex increases with the decrease in angulation of the elastics.

RESUMO Introdução: A protração maxilar com ancoragem esquelética intrabucal (I-SAMP) tem sido considerada um tratamento efetivo para a má oclusão esquelética de Classe III. Objetivo: O presente estudo in silico avaliou, usando análise de elementos finitos, a influência de diferentes direções da força dos elásticos Classe III com ancoragem esquelética intrabucal nas mudanças no complexo craniomaxilofacial. Métodos: Um modelo de elementos finitos tridimensional (3D) dos ossos craniomaxilofaciais, incluindo as suturas circum-maxilares, foi construído, com alta semelhança biológica. Uma montagem 3D de quatro miniplacas foi projetada e fixada na maxila e na mandíbula do modelo de elementos finitos. O modelo foi aplicado com o uso de 250g/força nas miniplacas em três angulações (10°, 20° e 30°) em relação ao plano oclusal, para medir as tensões e os deslocamentos, usando o programa ANSYS. Resultados: As suturas zigomaticotemporal, zigomaticomaxilar e esfenozigomática desempenharam um papel significativo no deslocamento para anterior e na rotação anti-horária da maxila e do zigoma, independentemente da angulação na aplicação da força. Os deslocamentos e as rotações do complexo zigomático-maxilar diminuíram gradualmente com o aumento de 10° para 30° no ângulo de aplicação da força entre as miniplacas. A mandíbula apresentou deslocamento irrelevante, com rotação no sentido horário. Conclusões: Os efeitos do tratamento com I-SAMP foram corroborados, com um vislumbre dos padrões de deslocamento e das suturas envolvidas, que não existiam nos estudos com imagens 2D e 3D realizados anteriormente. A angulação dos elásticos Classe III ancorados esqueleticamente deve ser a menor possível, visto que o deslocamento do complexo zigomático-maxilar aumenta com a redução no ângulo dos elásticos.

Biomechanical effects of Skeletally anchored Class III elastics on the maxillofacial complex: a 3D finite element analysis.

BACKGROUND: Although, the outcomes and changes in the maxillofacial complex after the application of intraoral bone anchored Class III elastics, have been reported by multiple clinical studies, there was no finite element study to assess and evaluate the stress pattern and displacement on maxillomandibular complex with bimaxillary anchorage. The present study aims to evaluate the biomechanical effects on maxillomandibular complex of Skeletally anchored Class III elastics with varying angulations using the 3D finite element analysis. METHODOLOGY: Two 3-dimensional analytical models were developed using the Mimics 8.11 (Materialise: Leuven, Belgium) and ANSYS software Version 12.1 (ANSYS Inc, Canonsburg, PA, USA) from sequential computed tomography images taken from a Skeletal Class III subject. The models were meshed into 465,091 tetrahedral elements and 101,247 nodes. Intraoral mechanics for skeletally anchored maxillary protraction (I-SAMP) were applied on two models i.e. A and B (without and with maxillary expansion respectively) between miniplates on maxilla and mandible on both right and left sides with three different angulations of forces-10°, 20° and 30°). RESULTS: Although the craniomaxillary complex in both the models (A and B) displaced forward while demonstrating rotations in opposite directions, the displacements and rotations decreased gradually with the increase of the angle of load application from 10° to 30°. The mandible rotated clockwise in both the simulations, but the displacement of mandibular surface landmarks was higher in Simulation A. However, the antero-inferior displacement of the glenoid fossa was higher in Simulation B than in A. CONCLUSION: Significant displacement of maxillofacial sutures and structures was witnessed with I-SAMP with maxillary expansion and Class III elastics for correction of Skeletal Class III with maxillary retrognathism. Thus, I-SAMP with maxillary expansion is a desired protocol for treatment of maxillary retrognathism. However, the prescribed angulation of the Class III elastics should be as low as possible to maximise the desired effects.

Effect of photobiomodulation on external root resorption during orthodontic tooth movement - a randomized controlled trial.

OBJECTIVE: The objective of the study was to compare external root resorption during orthodontic tooth movement between patients who were subjected to photobiomodulation and those who were not. MATERIALS AND METHODS: The study was designed as a split-mouth, single-blind randomized controlled trial conducted on twenty-two orthodontic patients requiring extraction of maxillary first premolars (age group 13-30years). A buccal force was applied to all the premolars using a 0.019″×0.025″ beta-titanium cantilever spring for 28days. The test group premolars were irradiated by indium-gallium-arsenide (InGaAs) diode laser (980nm, 100mW) 0, 3, 7, 11, 15 and 28days after force application. Each premolar was irradiated at ten locations on the buccal and palatal gingiva resulting in a total energy of 10J delivered per tooth. After 28days, the root surface of all the premolars were studied for the number and volume of resorption craters using three-dimensional optical profilometry by a blinded assessor. One-sample Kolmogorov-Smirnov test was used to ascertain normality and Mann-Whitney U test was applied for data analysis. RESULTS: All twenty-two patients enrolled completed the study. The root surface analysis showed formation of 32.78% less number of resorption craters (P<0.05) and 39.49% less volume of resorption craters (P<0.05) in the test group premolars relative to the control group premolars. CONCLUSIONS: The results of the present study, therefore, suggest that photobiomodulation reduces external root resorption during orthodontic tooth movement. TRIAL REGISTRATION/REGISTRATION NUMBER: CTRI/2018/04/013520.

SEM Evaluation of Enamel Surface Changes and Enamel Microhardness around Orthodontic Brackets after Application of CO2 Laser, Er,Cr:YSGG Laser and Fluoride Varnish: An In vivo Study.

INTRODUCTION: One of the most undesirable consequences of orthodontic treatment is occurrence of enamel demineralization around orthodontic brackets. Numerous in vitro studies have reported the prevention of enamel demineralization by surface treatment with lasers and fluoride varnish. AIM: To evaluate the changes on the enamel surface and microhardness around orthodontic brackets after surface treatment by CO2 laser, Er, Cr:YSGG laser and fluoride varnish in vivo. MATERIALS AND METHODS: A double blind interventional study was carried out on 100 premolars which were equally divided into five groups, out of which one was the control group (Group 0). The intervention groups (Group I to IV) comprised of patients requiring fixed orthodontic treatment with all 4 first premolars extraction. Brackets were bonded on all 80 premolars which were to be extracted. Enamel surface treatment of Groups I, II and III was done by CO2 laser, Er, Cr:YSGG laser and 5% sodium fluoride varnish respectively and Group IV did not receive any surface treatment. A modified T-loop was ligated to the bracket and after two months, the premolars were extracted. Surface changes were evaluated by Scanning Electron Microscopic (SEM) and microhardness testing. Comparison of mean microhardness between all the groups was assessed using post-hoc test with Bonferroni correction. RESULTS: Group I showed a melted enamel appearance with fine cracks and fissures while Group II showed a glossy, homogenous enamel surface with well coalesced enamel rods. Group III showed slight areas of erosions and Group IV presented areas of stripped enamel. Significant difference was observed between the mean microhardness (VHN) of Group I, Group II, Group III, Group IV and Group 0 with p<0.001. A significant difference of p<0.001 was observed while comparing Group I vs II,III,IV,0 and Group II vs III,IV,0. However, difference while comparing Group III vs IV was p=0.005 and difference between the mean microhardness of Group 0 vs Group III was non significant. CONCLUSION: Surface treatment with Er,Cr:YSGG laser causes a positive alteration of the enamel surface increasing its ability to resist demineralization with optimum microhardness as compared to CO2 laser and sodium fluoride varnish.

Prospective Evaluation of Psychosocial Impact after One Year of Orthodontic Treatment Using PIDAQ Adapted for Indian Population.

INTRODUCTION: The impact of dental appearance, malocclusion and treatment for the same on psychological and functional well-being has drawn increasing attention over the past decade. Various psychometric instruments alongside normative indices have been used to predict orthodontic concerns. Evaluating the patients' experience during the orthodontic treatment can help us understand the true benefits and advantages of orthodontic therapy. AIM: The aim of the present study was to evaluate the change in the psychosocial impact of malocclusion using the Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ) adapted for the Indian population after one year of fixed orthodontic treatment. MATERIALS AND METHODS: This interventional study was conducted on 93 patients requiring fixed orthodontic treatment. Brazilian, Chinese, Spanish, Nepali and Moroccan versions of the PIDAQ have been published but the questionnaire is not available in Hindi. In the present study, the original PIDAQ was translated into Hindi language to adapt it for the Indian population and was validated by back translation and pretest. All the subjects answered the Hindi version of the questionnaire at pretreatment (T1) and at one year of orthodontic treatment (T2). Additionally, the Index of Orthodontic Treatment Need (IOTN) was applied to measure the severity and self-perception of malocclusion. The data were analysed using paired t-test, Wilcoxon signed rank test and Kruskal-Wallis test. RESULTS: Significant reduction was found in the total PIDAQ score and each factor's score (p<0.001) after one year of orthodontic treatment. There was a positive association of the psychosocial impact of malocclusion with the IOTN-AC (IOTN-Aesthetic Component). Adolescent females were found to be most concerned with their dentofacial appearance. CONCLUSION: Results showed significant improvement in the psychosocial impact of malocclusion with a reduction in the self-perceived needs of patients with orthodontic treatment. The psychometric instrument used may be recommended as an Oral Health Related Quality of Life (OHRQoL) assessment tool for the population in India for further research.

Serum IGF-1, IGFBP-3 and their ratio: Potential biochemical growth maturity indicators.

BACKGROUND: Determination of skeletal maturation and remaining growth potential is an essential part of treatment planning in orthodontics. The aim of our study was to determine the relationship between IGF-1 levels, IGFBP-3 levels with CVM staging to track the pre pubertal and pubertal growth spurts in female patients in North Indian population. METHODS: This cross-sectional study was conducted on ninety female subjects in the age group of 8-20 years. Blood samples were collected and centrifuged and serum samples were then analysed by Human IGF-1 and IGFBP-3 enzyme-linked immunosorbent assay kits, specific for IGF-1 and IGFBP-3, respectively. CVM staging on lateral cephalometric radiograph was determined for all patients. Analysis of variance test followed by a post hoc test was used to compare mean IGF-1 and IGFBP-3 corresponding to six stages of cervical vertebrae maturation stages. Linear Pearson's correlations were performed to determine the trends of IGF-1, IGFBP-3, and its ratio relating to CVM stage. The kappa statistic was used to measure inter and intra examiner reliability. P value <0.05 was considered as statistically significant. RESULTS: Mean serum IGF-1 levels were found to be highest (403.3 ± 12.3 ng/ml) at CVMI3 stage of CVMI. The post-hoc test revealed a significant difference in IGF-1 levels between all stages of CVMI, thereby indicating a specific range of IGF-1 levels for a specific skeletal stage. Mean serum IGFBP-3 levels were found to be highest (5186.8 ± 1384.2 ng/ml) at CVMI4 stage of CVMI. The mean serum IGFBP-3 levels at CVMI4 were found to be significantly higher than the levels at all other CVMI stages except CVMI3 stage. CONCLUSIONS: IGF-1 and IGFBP-3 can serve as a potential biochemical indicator for assessment of skeletal maturity.

Evaluation of orthodontic mini-implant placement: a CBCT study.

BACKGROUND: Optimal positioning of orthodontic mini-implants is essential for a successful treatment with skeletal anchorage. This study aims to compare the accuracy of two-dimensional radiographs with a cone beam computed tomography (CBCT) for mini-implant placement. METHODS: An ideal site for mini-implant placement at the buccal interradicular space between the second premolar and the first molar was determined for 40 sites (in 13 patients aged 14 to 28 years) by using CBCT data. The mini-implant placement procedure was then divided into two groups. In CBCT group, mini-implants were placed at the sites determined from CBCT data. In RVG group, mini-implants were placed with the help of two-dimensional digital radiographs and a custom made guide. Postplacement CBCT scans were obtained to determine the accuracy of the mini-implant placement. The results were statistically analyzed with a Mann-Whitney test. RESULTS: A statistically significant difference (p value=0.02) was observed between the two groups for deviation from an ideal height of placement of the mini-implants. Deviations in mesiodistal positioning and angular deviation showed a statistically non-significant difference. Three out of twenty mini-implants in the RVG group showed root contact in the mandibular arch that may be attributed to the narrower interradicular space and reduced accessibility in the mandibular posterior region. CONCLUSIONS: Although CBCT provides an accurate three-dimensional visualization of the interradicular space, the two-dimensional intraoral radiograph of the interradicular area provides sufficient information for mini-implant placement. Considering the amount of radiation exposure and cost with the two techniques, it is recommended to use two-dimensional radiographs with a surgical guide for a routine mini-implant placement.