scholarly journals The biomechanics of posterior maxillary arch expansion using fixed labial and lingual appliances

2020 ◽  
Vol 90 (5) ◽  
pp. 688-694
Author(s):  
Harsimrat Kaur ◽  
Brandon Owen ◽  
Bill Tran ◽  
Raymond Guan ◽  
Jeramy Luo ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Posterior Arch ◽  
Posterior Teeth ◽  
Significance Level ◽  
Arch Form ◽  
Second Molar ◽  
Force Moment ◽  
Vertical Displacements ◽  
Initial Force ◽  
Maxillary Arch

ABSTRACT Objective To compare the biomechanics of straight labial, straight lingual, and mushroom lingual archwire systems when used in posterior arch expansion. Materials and Methods An electro-mechanical orthodontic simulator allowing for buccal–lingual and vertical displacements of individual teeth and three-dimensional force/moment measurements was instrumented with anatomically shaped teeth for the maxillary arch. In-Ovation L brackets were bonded to lingual surfaces, and Carriere SLX brackets were bonded to labial surfaces to ensure consistency of slot dimensions. Titanium molybdenum archwires were bent to an ideal arch form, and the teeth on the orthodontic simulator were set to a passive position. Posterior teeth from the canine to second molar were moved lingually to replicate a constricted arch. From the constricted position, the posterior teeth were simultaneously moved until the expansive force decreased below 0.2 N. Initial force/moment systems and the amount of predicted expansion were compared for posterior teeth at a significance level of α = 0.05. Results Archwire type affected both the expected expansion and initial force/moment systems produced in the constricted position. In general, the lingual systems produced the most expansion. The archwire systems were not able to return the teeth to their ideal position, with the closest system reaching 41% of the intended expansion. Conclusions In general, lingual systems were able to produce greater expansion in the posterior regions when compared with labial systems. However, less than half of the intended arch expansion was achieved with all systems tested.

scholarly journals Evaluation of Efficacy of Various Implants in Maxillary Arch Distalization - A Finite Element Analysis

2020 ◽  
Vol 10 (1) ◽  
pp. 44-54
Author(s):  
Sneha Sanap ◽  
Vinit Swami ◽  
Amol Patil ◽  
Shailesh Deshmukh ◽  
Veera Bhosale
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Effective Means ◽  
Three Dimensional ◽  
Element Model ◽  
Class Ii ◽  
Maximum Amount ◽  
Element Analysis ◽  
Second Molar ◽  
Maxillary Arch

Introduction: Orthodontic correction of Angle’s class II molar relation has, for long, been one of the challenges in orthodontics, with various researchers attempting to correct the class II molar relationship by diverse methods. One of the techniques that has gained popularity in recent times is maxillary arch distalization by infrazygomatic screws and miniscrews. The objective of the study is to measure and compare the amount of maxillary arch distalization and its effects, on adjacent teeth, by varying the positions of mini-implants by Finite Element Analysis. Materials & Method: A standard three-dimensional finite element model was constructed to simulate the maxillary teeth, periodontal ligament, and alveolar process. In this study, three models were prepared. Model-1: The (miniscrews) were placed between upper first and second premolar, and between second premolar and first molar bilaterally. Model-2: Infrazygomatic screws was placed between upper first and second molar bilaterally. Model-3: Infrazygomatic screws was placed on the mesio-buccal root of upper first molar bilaterally. The displacement of each tooth was calculated on x, y, and z axes when 200 gm of force was applied on each side. Result: Maximum amount of maxillary arch distalization was seen when infrazygomatic screws placed between upper first and second molar in model-2. Whereas maximum amount of maxillary arch intrusion and less distalization was observed when miniscrews placed between upper first premolar and second premolar and in between second premolar and upper first molar in model-1. The difference was statistically significant (p=0.005*). There was no bucco-palatal rotation of teeth observed among all three finite element models. Conclusion: Thus infrazygomatic screws and miniscrews are the effective means of maxillary arch distalization for the correction of Class II malocclusion.

scholarly journals Correlation of Three Dimensions of Palate with Maxillary Arch Form and Perimeter as Predictive Measures for Orthodontic and Orthognathic Surgery

Children ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 514
Author(s):  
Fadil A. Kareem ◽  
Aras Maruf Rauf ◽  
Tara Ali Rasheed ◽  
Falah Abdullah Hussain
Keyword(s):  
Hard Palate ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Strong Positive Correlation ◽  
Strong Negative Correlation ◽  
Arch Form ◽  
Positive Correlation ◽  
Orthodontic Patients ◽  
The City ◽  
Maxillary Arch

Hard palate is regarded as an important part of the human skull, which contributes to the separation of the oral and nasal cavities. The aims of the study were to investigate the morphology of the hard palate in order to create a general guideline of three-dimensional values of the palate in a Kurdish sample in the city of Sulaimani as well as determining the possible correlations between different palatal parameters in class I malocclusion with the maxillary arch form and perimeter. A retrospective study design was adopted by collecting 100 study models of orthodontic patients aged 16–24 years old attending different private dental clinics in the city of Sulaimani seeking orthodontic management. In this study, three-dimensional palatal measurements including depth, length, and width were measured in an attempt to discover their correlation with each maxillary arch form and perimeter. Additionally, measurements of inter-molar width, inter-canine width, and arch perimeter were carried out. About two-thirds of those seeking orthodontic treatment were females. Nearly 80% of the study sample had narrow palate followed by 15 and 5% of intermediate palate and broad palate, respectively. In regard to arch form, almost 90% of subjects were with tapered maxillary arch form and 10% of them with oval arch form. Males had increased dimensions compared to females, with significant differences, except in palatal depth in the molar area, and palatine height index, in which females showed increased dimensions than males but the differences were statistically non-significant. A strong positive correlation was observed between arch form and canine depth. In regard to arch perimeter, a strong negative correlation was found with molar depth and a medium positive correlation with each of canine depth, palatal width, and palatal length.

scholarly journals A CBCT evaluation of molar uprighting by conventional versus microimplant-assisted methods: an in-vivo study

2018 ◽  
Vol 23 (3) ◽  
pp. 35.e1-35.e9
Author(s):  
Sergio Martires ◽  
Nandini V. Kamat ◽  
Sapna Raut Dessai
Keyword(s):  
Prospective Study ◽  
Three Dimensional ◽  
Vertical Plane ◽  
Statistical Analyses ◽  
Significance Level ◽  
Second Molar ◽  
Dimensional Effects ◽  
The Mean

ABSTRACT Objective: The aim of this prospective study was to compare the three-dimensional effects of the conventional helical uprighting spring (CA) and the mini-implant assisted helical uprighting spring (MIA), using CBCT scans. Methods: Twenty patients with mesially tipped second mandibular molars were divided into two groups: CA group, in which 10 patients were treated using a conventional helical uprighting spring with conventional anchorage; and MIA group, in which 10 patients were treated using a mini-implant supported uprighting spring. Molar uprighting was observed in both groups for a period of four months. Two standardized 11×5-cm CBCT sections of the mandible were taken, being one prior to uprighting and one at the end of the four month follow-up. Statistical analyses at the beginning of treatment and after a 4 month follow-up were performed, with a significance level of p< 0.05. Results: The mean amount of change in mesiodistal angulation in the MIA group was 8.53 ± 2.13o (p< 0.001) and in the CA group was 9.8 ± 0.5o (p< 0 .001). Statistically significant differences were found between the two groups with regard to buccolingual inclination of canine, first and second premolars (p< 0.05), second molar (p< 0.001) and extrusion of second molar (p< 0.05). Conclusions: The mean amount of change in the mesial angulation of the second molar in the CA as well as the MIA groups was similar. MIA, which used mini-implant as a source of anchorage, was more effective in preventing movement of the anchorage teeth as well as preventing extrusion of the second molar in the vertical plane, when compared to the CA group, which used dental units as a source of anchorage.

scholarly journals Composite hollow truss with multiple vierendeel panels

2013 ◽  
Vol 66 (4) ◽  
pp. 431-438
Author(s):  
Augusto Ottoni Bueno da Silva ◽  
Newton de Oliveira Pinto Júnior ◽  
João Alberto Venegas Requena
Keyword(s):  
Bearing Capacity ◽  
Failure Modes ◽  
Three Dimensional ◽  
Analytical Calculation ◽  
Two Dimensional ◽  
Shear Forces ◽  
Vertical Displacements ◽  
New System ◽  
The Ideal

The aim of this study was to evaluate through analytical calculation, two-dimensional elastic modeling, and three-dimensional plastic modeling, the bearing capacity and failure modes of composite hollow trusses bi-supported with a 15 meter span, varying the number of central Vierendeel panels. The study found the proportion span/3 - span/3 - span/3, as the ideal relationship for the truss - Vierendeel - truss lengths, because by increasing the proportion of the length occupied by the central Vierendeel panels, the new system loses stiffness and no longer supports the load stipulated in the project. Furthermore, they can start presenting excessive vertical displacements and insufficient resistance to external shear forces acting on the panels.

scholarly journals Energetic particle induced intra-seasonal variability of ozone inside the Antarctic polar vortex observed in satellite data

2015 ◽  
Vol 15 (6) ◽  
pp. 3327-3338 ◽  
Author(s):  
T. Fytterer ◽  
M. G. Mlynczak ◽  
H. Nieder ◽  
K. Pérot ◽  
M. Sinnhuber ◽  
...  
Keyword(s):  
Geomagnetic Activity ◽  
Seasonal Variability ◽  
Transport Model ◽  
Three Dimensional ◽  
Polar Vortex ◽  
Quiet Time ◽  
Significance Level ◽  
Antarctic Polar Vortex ◽  
Ap Index ◽  
The Antarctic

Abstract. Measurements from 2002 to 2011 by three independent satellite instruments, namely MIPAS, SABER, and SMR on board the ENVISAT, TIMED, and Odin satellites are used to investigate the intra-seasonal variability of stratospheric and mesospheric O3 volume mixing ratio (vmr) inside the Antarctic polar vortex due to solar and geomagnetic activity. In this study, we individually analysed the relative O3 vmr variations between maximum and minimum conditions of a number of solar and geomagnetic indices (F10.7 cm solar radio flux, Ap index, ≥ 2 MeV electron flux). The indices are 26-day averages centred at 1 April, 1 May, and 1 June while O3 is based on 26-day running means from 1 April to 1 November at altitudes from 20 to 70 km. During solar quiet time from 2005 to 2010, the composite of all three instruments reveals an apparent negative O3 signal associated to the geomagnetic activity (Ap index) around 1 April, on average reaching amplitudes between −5 and −10% of the respective O3 background. The O3 response exceeds the significance level of 95% and propagates downwards throughout the polar winter from the stratopause down to ~ 25 km. These observed results are in good qualitative agreement with the O3 vmr pattern simulated with a three-dimensional chemistry-transport model, which includes particle impact ionisation.

FUNCTIONALLY GENERATED PATH TECHNIQUES FOR A HARMONIOUS OCCLUSION – A REVIEW

2021 ◽  
pp. 28-29
Author(s):  
Aayush Oswal ◽  
Krishna Kumar ◽  
Gautham Shetty ◽  
Sindhu Sudhakar Kumararama
Keyword(s):  
Tooth Movement ◽  
Three Dimensional ◽  
Posterior Teeth ◽  
Occlusal Adjustment ◽  
Dental Prostheses ◽  
Single Crown ◽  
Masticatory System

Harmonious occlusion is a critical prerequisite for successful prosthodontic rehabilitation. Conventional techniques for construction of the prosthesis have not been successful in producing a prosthesis that can be inserted without intraoral occlusal adjustment. The functionally generated pathway (FGP) technique includes registration of the occlusal pathways of the posterior teeth in the functional wax and has been classically described as the "three-dimensional static expression of dynamic tooth movement. The functionally generated path technique employs the patient's masticatory system to develop occlusion. It has various advantages like being simple, accurate, and reliable. The technique will require only minor intraoral occlusal adjustments if done in a proper way. It’s highly versatile and can be utilized to develop occlusal pattern in removable and xed dental prostheses including implant restorations. It can also be employed with equal efcacy in fabrication of relatively simple restorations such as a single crown, or more complex full mouth reconstructions.

scholarly journals Is there an association between skeletal asymmetry and tooth absence?

2016 ◽  
Vol 21 (4) ◽  
pp. 73-79 ◽  
Author(s):  
Guilherme Thiesen ◽  
Bruno Frazão Gribel ◽  
Keila Cristina Rausch Pereira ◽  
Maria Perpetua Mota Freitas
Keyword(s):  
Cross Sectional Study ◽  
Midsagittal Plane ◽  
Chi Square ◽  
Cross Sectional ◽  
Posterior Teeth ◽  
Significance Level ◽  
Posterior Tooth ◽  
Mandibular Asymmetry ◽  
Significant Difference ◽  
Skeletal Asymmetry

ABSTRACT Introduction: Facial skeletal asymmetry is commonly found in humans and its main characteristic is menton deviation. The literature suggests that occlusal and masticatory problems arising from tooth absence could be related to the development of such asymmetries. Objective: The aim of this cross-sectional study was to estimate the prevalence of mandibular skeletal asymmetries and to investigate its association with posterior tooth absences. Methods: Tomographic images of 952 individuals aged from 18 to 75 years old were used. Asymmetry was the analyzed outcome, and it was categorized into three groups according to gnathion displacement in relation to the midsagittal plane (relative symmetry, moderate asymmetry, and severe asymmetry). Patients were sorted by the presence of all posterior teeth, unilateral posterior tooth absence, or bilateral posterior tooth absence. Chi-square test with a significance level of 5% was used to verify the association between posterior tooth absence and asymmetry. Results: Results show relative symmetry present in 55.3% of the sample, as well as the prevalence of 27.3% for moderate mandibular asymmetry and 17.4% for severe asymmetry. Moderate and severe mandibular asymmetries occurred in a higher proportion in patients with unilateral posterior tooth absence. However, there was no statistically significant difference between the analyzed groups (p = 0.691). Conclusions: In this study, mandibular asymmetries did not present any association with the absence of teeth on the posterior area of the arch.

Three-Dimensional Comparison between the Palatal Forms in Complete Unilateral Cleft Lip and Palate with and without Hotz Plate from Cheiloplasty to Palatoplasty

1996 ◽  
Vol 33 (4) ◽  
pp. 312-317 ◽  
Author(s):  
Katsuaki Mishima ◽  
Toshio Sugahara ◽  
Yoshihide Mori ◽  
Masayoshi Sakuda
Keyword(s):  
Nasal Cavity ◽  
Cleft Lip ◽  
Cleft Lip And Palate ◽  
Three Dimensional ◽  
Alveolar Ridge ◽  
Maxillary Arch ◽  
Alveolar Arch

The palatal forms in 20 infants with a complete unilateral cleft lip, and palate (12 with a Hotz plate and 8 without, selected at random) were studied from birth until 18 months of age. Using techniques developed previously, the degree of curvature In the palate and the magnitude of migration of the maxillary segments were measured three-dimensionally. Furthermore, using a newly developed method to approximate a set of the points on the alveolar ridge to a circle in a plane, the form of the alveolar arch was evaluated. Results from the group with a Hotz plate revealed that the plate possesses four effects not seen in the group without a Hotz plate. The size of the palate was larger, and the sagittal gap between the two segments of the maxilla was smaller. These results suggest that the appliance could stimulate the growth of the segments and could prevent collapse of the maxillary arch from the force of lip closure. Third, the steepness of the segments toward the nasal cavity was smaller, possibly occurring because the appliance prevents tongue intrusion into the cleft. Fourth, the magnitude of migration of the lesser segment toward the cleft edge of the major segment was larger. This result suggests that the appliance could guide the growth of the maxillary segments to narrow the cleft width until 18 months of age.

scholarly journals Three-dimensional analysis of the physiologic drift of adjacent teeth following maxillary first premolar extractions

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Fei Teng ◽  
Fei-Yu Du ◽  
Hui-Zhong Chen ◽  
Ruo-Ping Jiang ◽  
Tian-Min Xu
Keyword(s):  
Three Dimensional ◽  
Posterior Teeth ◽  
Fixed Appliance ◽  
Premolar Extraction ◽  
Negative Effect ◽  
Vertical Changes ◽  
Anchorage Loss ◽  
Drift Models ◽  
To Receive ◽  
Positive Effect

Abstract We assessed the three-dimensional (3D) pattern of the physiologic drift of the remaining adjacent teeth after premolar extraction due to orthodontic reasons and the associated factors. Data were collected from 45 patients aged 17.04 ± 5.14 years who were scheduled to receive a fixed appliance after maxillary premolar extraction. Seventy-five drift models were obtained and digitalized via 3D scanning. The average physiologic drift duration was 81.66 ± 70.03 days. Angular and linear changes in the first molars, second premolars, and canines were measured using the 3D method. All the examined teeth had tipped and moved towards the extraction space, leading to space decreases. Posterior teeth primarily exhibited significant mesial tipping and displacement, without rotation or vertical changes. All canine variables changed, including distal inward rotation and extrusion. The physiologic drift tended to slow over time. Age had a limited negative effect on the mesial drift of posterior teeth, whereas crowding had a limited positive effect on canine drift. Thus, the mesial drift of molars after premolar extraction may lead to molar anchorage loss, particularly among younger patients. The pattern of the physiologic drift of maxillary canines can help relieve crowding and facilitate labially ectopic canine alignment, whereas canine drift is accelerated by more severe crowding.

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