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.

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.

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.

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.

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.

Hepatoprotective action of abhrak bhasma, an ayurvedic drug in albino rats against hepatitis induced by CCl4

Abhrak bhasma is a commonly used ayurvedic drug against many diseases including hepatitis. It is tested in albino rats using a model of hepatitis induced by a single dose of CCl4 (3 ml/kg body wt). Different doses of abhrak bhasma (10, 20, 30 and 40 mg/kg body wt) were tested to decide the dose related hepatoprotective efficacy. The centrolobular necrosis induced by single dose of CCl4 was reduced significantly by abhrak bhasma (10 mg) and liver histology was also protected by 20 mg dose. Liver acid lipase activity was lowered, while alkaline and lipoprotein lipase activities were elevated due to treatment of single dose of CCl4. Abhrak bhasma counteracted the action of CCl4 on liver lipolytic enzymes. CCl4 did not alter the kidney histologically. Activities of three lipases of rat kidney (acid, alkaline and lipoprotein lipases) were reduced by CCl4 treatment and were reversed by administration of abhrak bhasma. Acid lipase activity of rat adipose tissue was reduced by CCl4 treatment. On the contrary alkaline, lipoprotein and hormone sensitive lipases were enhanced after 24 hr of administration of CCl4. Acid lipase activity was raised by administration of different doses of abhrak bhasma concurrent with CCl4. Abhrak bhasma treatment along with CCl4 enhanced alkaline lipase activity at 10 and 20 mg dose and later it was reduced at 30 and 40 mg doses and came to normal levels. Lipoprotein and hormone sensitive lipases were reduced by the counteraction of increasing doses of abhrak bhasma.

Antianaemic properties of ayurvedic drugs, raktavardhak, punarnavasav and navayas louh in albino rats during phenylhydrazine induced haemolytic anaemia

Single injection of phenylhydrazine[PH] reduced the number of RBC and haemoglobin content; decreased myeloid; erythroid cell ratio in bone marrow and increased Cathepsin D activity in spleen of rats. Ayurvedic drugs raktavardhak, punarnavasav and navayas louh recovered the number of RBC and haemoglobin content and raised myeloid: erythroid cell ratio and normalised cathepsin D activities by counteracting the action phenyl hydrazine. The results confirm the claims of ayurveda that these drugs possess the potency to cure anaemia through protection of RBCs from haemolysis and simultaneously lowering cathepsin D activities from the spleen.

Curative effects of mandur bhasma on liver and kidney of albino rats after induction of acute hepatitis by CCl(4)

Hepatocurative effects of mandur bhasma were studied in albino rats after induction of acute hepatitis by CCl4 liquid paraffin and CCl4 + liquid param. Recovery of the liver was studied with reference to histological architecture and differential counts of degenerated, recovering and recovered hepatocytes. Alterations in the kidney were also studied histologically. Hepatotoxins were given (s.c.) daily for 11 days. Mandur bhasma was given (po) for 7 days to normal, CCl4, liquid paraffin and CCl4 + liquid paraffin treated rats from day 12 to day 18. There were no spontaneous liver and kidney recoveries within a week after the cessation of the treatments of hepatotoxins. Mandur bhasma treatment showed conspicuous recoveries of liver and kidney within a week and total recoveries were noticed after two weeks. Biochemical alterations in lipid peroxidation, glucose-phosphatase and total proteins were studied during present work. The alterations in the histology and biochemical parameters of liver and kidney show hepatocurative potency of mandur bhasma.

Cholesterol mediated changes in beta-glucuronidase activities of rat theca interstitial cells and granulosa cells

Effects of steroid hormones on beta-glucuronidase activities of granulosa cells and theca interstitial cells were studied in vitro in the presence and absence of cholesterol in minimum essential medium (MEM with Hank's salts). Conspicuous fall in the enzyme activities of both these cells were noticed during first 10 min of incubation in MEM without cholesterol and remained lower throughout the experiment. Addition of cholesterol to incubation medium maintained beta-glucuronidase activities of both the cells as observed in the cells of immature ovary immediately after isolation. 17 beta-estradiol did not affect beta-glucuronidase activities of these cells, while testosterone and progesterone suppressed the enzyme activities of these cells in the presence of cholesterol.

Effect of hepatoprotective ayurvedic drugs on lysosomal enzymes during hepatic injury induced by single dose of CCl4

Effects of single doses of kumari asav, kumari kalp, arogyavardhini and tamra bhasma on lysosomal enzymes (acid phosphatase and beta-glucuronidase) of rat liver and kidney were studied during hepatitis induced by single 0.3 ml/kg body wt dose of CCl4. Histologically all the drugs showed significant hepatoprotection. While acid phosphatase activities of liver and kidney were suppressed, activities of beta-glucuronidase were enhanced by these drugs. The results indicate that acid phosphatase and beta-glucuronidase behave differently, although they are lysosomal in nature.

Effect of hepatoprotective ayurvedic drugs on lipolytic activities during CCl4 induced acute hepatic injury in albino rats

Daily treatment of CCl4(3 ml/kg body wt) for 7 days induced acute hepatic necrosis in albino rats. Treatment of CCl4 caused significant alterations in the activities of acid lipase, alkaline lipase, lipoprotein lipase of liver, kidney and adipose tissue and hormone sensitive lipase of adipose tissue of albino rat. Administration of hepatoprotective ayurvedic drugs (kumari asav, kumari kalp, arogyavardhini and tamra bhasma) concomitant with CCl4 counteracted the action of CCl4 on lipolytic enzymes exhibiting hepatoprotection. The possible physiological significance of alterations in lipolytic enzymes during hepatic necrosis induced by CCl4 and hepatoprotection by the above ayurvedic drugs is discussed.

Effect of Plumbago zeylanica root powder induced preimplantationary loss and abortion on uterine luminal proteins in albino rats

P. zeylanica treatment during first 7 days of pregnancy abolished uterine proteins of 13,000, 19,000 and 26,000 and 75,000 Da molecular weights resulting in preimplantationary loss. Proteins having molecular weights 55,000 and 65,000 Da were absent in aborted rats, that were given P. zeylanica root powder since day 6 to day 17 of pregnancy. The results suggest that proteins having molecular weights 13,000, 19,000, 26,000 and 75,000 Da influence the implantation and proteins of 55,000 and 65,000 Da are required for the maintenance of the pregnancy.

Effect of hepatoprotective ayurvedic drugs on lipases following CCl4 induced hepatic injury in rats

Effects of kumari asav, kumari kalp, arogyavardhini and tamra bhasma used in Ayurved and Siddha medicine for the treatment of liver disorders have been studied on acid, alkaline and lipoprotein lipase activities of liver, adipose tissue and kidney and hormone sensitive lipase activity of adipose tissue following CCl4 induced liver injury in albino rats. The treatments of CCl4 and the above drugs show significant alterations in the lipolytic activities of liver, adipose tissue and kidney. Role of these enzymes during hepatoprotection by above drugs has been discussed.