scholarly journals A Prospective Comparative Study between the Software Models and Clinical Models of Clear Aligner Treatment

2019 ◽  
Vol 9 (1) ◽  
pp. 28-34
Author(s):  
Arisha Izhar ◽  
Gurkeerat Singh ◽  
Varun Goyal ◽  
Rajkumar Singh ◽  
Nishant Gupta ◽  
...  
Keyword(s):  
Tooth Movement ◽  
Three Dimensional ◽  
Prospective Clinical Study ◽  
Virtual Model ◽  
Posterior Teeth ◽  
Planning Stage ◽  
Anterior Crowding ◽  
Tooth Position ◽  
Software Models ◽  
The Mean

Introduction: The purpose of this prospective clinical study was to compare the three dimensional predicted software models with the stage clinical STL models and to evaluate the efficacy of tooth movement with clear aligners. Materials & Method: The sample size included 10 cases with mild anterior crowding treated with aligner therapy. The virtual model of the predicted tooth position was superimposed on the virtual model of the achieved tooth position at various stages over their stationary posterior teeth by using MeshLab software. The amount of tooth movement predicted was compared with the amount of tooth movement achieved. Result: The results of this study have shown that when a comparison was made on the basis of irregularity scores in both the groups, it was seen that the irregularity score was more in Clinical STL group at each stage such as 2.55 at T4, 1.65 at T6 and 1.0 at T8 whereas 2.0 at T4. 0.90 at T6 and 0.25 at T8 in the Software model group. Also, On comparing mean accuracy these three stages, the analysis of data showed the mean accuracy at T4 is 62.5%, mean accuracy at T6 is 68.8% and the mean accuracy at T8 is 78.1%. Conclusion: The predicted software models do not accurately reflect the patient’s tooth position .There is an overestimation by predicted software as compared to actual clinically achieved tooth position. There is a need of overcorrection to be built in the treatment planning stage itself and execution of the anticipated end result.

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 Application of a three-dimensional virtual model to study the effect of fluoroscopic angle on infra-acetabular corridor parameters and screw insertion rates

2021 ◽  
Author(s):  
Nengfeng Ma ◽  
Xufeng Hu ◽  
Zhoushan Tao ◽  
Min Yang
Keyword(s):  
3D Model ◽  
Three Dimensional ◽  
Reference Plane ◽  
Virtual Model ◽  
Screw Insertion ◽  
Pelvic Inlet ◽  
Line Angle ◽  
The Mean ◽  
Type Of Fracture ◽  
Tomography Data

Abstract Purpose To use three-dimensional (3D) virtual models to study how the parameters and insertion rates of the infra-acetabular corridor (IAC) change under different fluoroscopic angles. Methods The pelvis computed tomography data of 187 patients are imported into Mimics software in DICOM format to generate a 3D model. The anterior pelvis plane is used as the reference plane to measure the diameter of the optimum IAC when the pelvis model is tilted forward by 5°, 15°, 25°, 35° and 45°. The diameter of at least 3.5 mm is defined as the cutoff for placing a 3.5 mm screw, the rate of infra-acetabular screw (IAS) insertion is calculated, and the mean length of the IAC and the mean tilt of the corridor axis in relation to the sagittal midline plane (SMP) are measured. Results The similar diameters of the IAC can be found under fluoroscopy at 5°–35°, with the largest diameter of 4.08 ± 1.84 mm and the highest screw insertion rate of 60.42% at 15° and 25°, whereas the diameter and insertion rate are lowest at 45°. The corridor length increases with increasing fluoroscopic angle, and the angle of the corridor axis to the SMP decreases gradually. Conclusions The traditional 45° pelvic inlet radiograph is not suitable as the fluoroscopic angle for IAS insertion. The parameters of the IAC vary according to a certain rule under different fluoroscopic angles, so a surgeon can select the appropriate fluoroscopic angle in accordance with the type of fracture and the fracture line angle.

scholarly journals Application of a three-dimensional virtual model to study the effect of fluoroscopic angle on infra-acetabular corridor parameters and screw insertion rates

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Nengfeng Ma ◽  
Xufeng Hu ◽  
Zhoushan Tao ◽  
Min Yang
Keyword(s):  
3D Model ◽  
Three Dimensional ◽  
Reference Plane ◽  
Virtual Model ◽  
Screw Insertion ◽  
Pelvic Inlet ◽  
Line Angle ◽  
The Mean ◽  
Type Of Fracture ◽  
Tomography Data

Abstract Purpose To use three-dimensional (3D) virtual models to study how the parameters and insertion rates of the infra-acetabular corridor (IAC) change under different fluoroscopic angles. Methods The pelvis computed tomography data of 187 patients are imported into Mimics software in DICOM format to generate a 3D model. The anterior pelvis plane is used as the reference plane to measure the diameter of the optimum IAC when the pelvis model is tilted forward by 5°, 15°, 25°, 35° and 45°. The diameter of at least 3.5 mm is defined as the cutoff for placing a 3.5 mm screw, the rate of infra-acetabular screw (IAS) insertion is calculated, and the mean length of the IAC and the mean tilt of the corridor axis in relation to the sagittal midline plane (SMP) are measured. Results The similar diameters of the IAC can be found under fluoroscopy at 5°–35°, with the largest diameter of 4.08 ± 1.84 mm and the highest screw insertion rate of 60.42% at 15° and 25°, whereas the diameter and insertion rate are lowest at 45°. The corridor length increases with increasing fluoroscopic angle, and the angle of the corridor axis to the SMP decreases gradually. Conclusion The conventional fluoroscopic angle of the pelvic inlet is not suitable for the IAS insertion. The parameters of the IAC vary according to a certain rule under different fluoroscopic angles, so a surgeon can select the appropriate fluoroscopic angle in accordance with the type of fracture and the fracture line angle.

scholarly journals Three-dimensional analysis of tooth movement after intrusion of a supraerupted molar using a mini-implant with partial-fixed orthodontic appliances

2012 ◽  
Vol 83 (2) ◽  
pp. 274-279 ◽  
Author(s):  
Shin-Jae Lee ◽  
Sook-Yun Jang ◽  
Youn-Sic Chun ◽  
Won Hee Lim
Keyword(s):  
Tooth Movement ◽  
Treatment Time ◽  
Three Dimensional ◽  
3D Models ◽  
Orthodontic Appliances ◽  
Scanning System ◽  
3D Analysis ◽  
Fixed Orthodontic Appliances ◽  
The Mean ◽  
3D Software

ABSTRACT Objective: To evaluate three-dimensional (3D) positional changes of an intruded tooth, a neighboring tooth, and a tooth connected to a mini-implant following intrusion of a single supraerupted molar, using a mini-implant with partial-fixed orthodontic appliances. Materials and Methods: The study consisted of 14 adult patients (two males and 12 females, mean age 41.9 years) with a supraerupted molar due to loss of an antagonist. Intrusion was performed using a mini-implant with a partial strap-up. The mean treatment time was 11.9 months, and the mean retention time was 23.3 months. To quantify the positional changes of the teeth, 3D models using a laser-based, dental scanning system and 3D software at pretreatment, posttreatment, and retention were oriented in a coordinate system and superimposed using nonmoved teeth as references. The changes on the x-, y-, and z-axes were measured at the tip of each cusp in the involved teeth. Results: A supraerupted molar was intruded by a mean amount of 1.35 ± 0.48 mm and was well maintained during the retention period. The overall change in the neighboring tooth was insignificant, although it showed opposite movement compared to the intruded tooth during the intrusion. The tooth connected to a mini-implant exhibited a secure anchorage. Conclusion: 3D analysis showed the detailed positional changes of each tooth, and the involved molars were well maintained after intrusion.

scholarly journals Accelerated tooth movement with piezocision and its periodontal-transversal effects in patients with Class II malocclusion

2015 ◽  
Vol 86 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Sertac Aksakalli ◽  
Berra Calik ◽  
Burcak Kara ◽  
Seref Ezirganli
Keyword(s):  
Tooth Movement ◽  
Three Dimensional ◽  
Control Groups ◽  
Periodontal Health ◽  
Posterior Teeth ◽  
Premolar Extraction ◽  
Canine Distalization ◽  
Anchorage Loss ◽  
And Control ◽  
Experimental Group

ABSTRACT Objective:  To compare the extent of canine distalization and the transversal changes, postdistalization gingival indices, and mobility scores between patients who were undergoing orthodontic treatment involving upper premolar extraction with (experimental group) or without piezocision. Materials and Methods:  Twenty maxillary canines of 10 patients were evaluated with split mouth design. Pre- and postdistalization dental casts were prepared and scanned with an orthodontic scanner to compare the extent of distalization and transversal changes between the two groups. The pre- and postdistalization gingival indices and mobility scores were also calculated. Results:  Three-dimensional analysis of the models revealed significant differences in tooth movement (lesser anchorage loss and greater canine distalization) between the experimental and control groups. Furthermore, the distalization time was shortened in the experimental group. There were no differences in the transversal changes, pre- and postdistalization gingival indices, or mobility scores between groups. Conclusion:  Piezocision-assisted distalization accelerates tooth movement, decreases the anchorage loss for posterior teeth, and does not induce any maxillary transversal change. Moreover, piezocision does not have any adverse effects on periodontal health.

scholarly journals How accurate is Invisalign in nonextraction cases? Are predicted tooth positions achieved?

2017 ◽  
Vol 87 (6) ◽  
pp. 809-815 ◽  
Author(s):  
Thorsten Grünheid ◽  
Charlene Loh ◽  
Brent E. Larson
Keyword(s):  
Tooth Movement ◽  
Treatment Plan ◽  
Statistical Significance ◽  
Linear Measurements ◽  
Posterior Teeth ◽  
Tooth Position ◽  
Anterior Teeth ◽  
Angular Measurements ◽  
Tooth Type ◽  
Virtual Treatment

ABSTRACT Objective: To evaluate the accuracy of Invisalign technology in achieving predicted tooth positions with respect to tooth type and direction of tooth movement. Materials and Methods: The posttreatment models of 30 patients who had nonextraction Invisalign treatment were digitally superimposed on their corresponding virtual treatment plan models using best-fit surface-based registration. The differences between actual treatment outcome and predicted outcome were computed and tested for statistical significance for each tooth type in mesial-distal, facial-lingual, and occlusal-gingival directions, as well as for tip, torque, and rotation. Differences larger than 0.5 mm for linear measurements and 2° for angular measurements were considered clinically relevant. Results: Statistically significant differences (P < .05) between predicted and achieved tooth positions were found for all teeth except maxillary lateral incisors, canines, and first premolars. In general, anterior teeth were positioned more occlusally than predicted, rotation of rounded teeth was incomplete, and movement of posterior teeth in all dimensions was not fully achieved. However, except for excess posttreatment facial crown torque of maxillary second molars, these differences were not large enough to be clinically relevant. Conclusions: Although Invisalign is generally able to achieve predicted tooth positions with high accuracy in nonextraction cases, some of the actual outcomes may differ from the predicted outcomes. Knowledge of dimensions in which the final tooth position is less consistent with the predicted position enables clinicians to build necessary compensations into the virtual treatment plan.

Electron Holographic Nano-Characterization of Gold Catalyst at Interface

2002 ◽  
Vol 727 ◽  
Author(s):  
S. Ichikawa ◽  
T. Akita ◽  
M. Okumura ◽  
M. Haruta ◽  
K. Tanaka
Keyword(s):  
Contact Angle ◽  
Titanium Oxide ◽  
Gold Catalyst ◽  
Three Dimensional ◽  
High Resolution Electron Microscopy ◽  
Electron Holography ◽  
Gold Particles ◽  
Oxide Support ◽  
The Mean ◽  
A Charge

AbstractThe catalytic properties of nanostructured gold catalyst are known to depend on the size of the gold particles and to be activated when the size decreases to a few nanometers. We investigated the size dependence of the three-dimensional nanostructure on the mean inner potential of gold catalysts supported on titanium oxide using electron holography and high-resolution electron microscopy (HREM). The contact angle of the gold particles on the titanium oxide tended to be over 90° for gold particles with a size of over 5 nm, and below 90° for a size of below 2 nm. This decreasing change in the contact angle (morphology) acts to increase the perimeter and hence the area of the interface between the gold and titanium oxide support, which is considered to be an active site for CO oxidation. The mean inner potential of the gold particles also changed as their size decreased. The value of the inner potential of gold, which is approximately 25 V in bulk state, rose to over 40 V when the size of the gold particles was less than 2 nm. This phenomenon indicates the existence of a charge transfer at the interface between gold and titanium oxide. The 3-D structure change and the inner potential change should be attributed to the specific electronic structure at the interface, owing to both the “nano size effect” and the “hetero-interface effect.”

The Influence of Blade Wakes on the Performance of Interturbine Diffusers

1996 ◽  
Vol 118 (2) ◽  
pp. 347-352 ◽  
Author(s):  
R. G. Dominy ◽  
D. A. Kirkham
Keyword(s):  
Performance Modeling ◽  
Three Dimensional ◽  
Secondary Flows ◽  
Two Dimensional ◽  
Correct Performance ◽  
Analysis Methods ◽  
Flow Factor ◽  
The Mean ◽  
Lp Turbine

Interturbine diffusers provide continuity between HP and LP turbines while diffusing the flow upstream of the LP turbine. Increasing the mean turbine diameter offers the potential advantage of reducing the flow factor in the following stages, leading to increased efficiency. The flows associated with these interturbine diffusers differ from those in simple annular diffusers both as a consequence of their high-curvature S-shaped geometry and of the presence of wakes created by the upstream turbine. It is shown that even the simplest two-dimensional wakes result in significantly modified flows through such ducts. These introduce strong secondary flows demonstrating that fully three-dimensional, viscous analysis methods are essential for correct performance modeling.

scholarly journals Proximity of the middle meningeal artery and maxillary artery to the mandibular head and mandibular neck as revealed by three-dimensional time-of-flight magnetic resonance angiography

2021 ◽  
Author(s):  
Daphne Schönegg ◽  
Raphael Ferrari ◽  
Julian Ebner ◽  
Michael Blumer ◽  
Martin Lanzer ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Magnetic Resonance Angiography ◽  
Three Dimensional ◽  
Time Of Flight ◽  
Middle Meningeal Artery ◽  
Individual Variability ◽  
Maxillary Artery ◽  
Condylar Process ◽  
The Mean ◽  
Meningeal Artery

Abstract Purpose The close topographic relationship between vascular and osseous structures in the condylar and subcondylar region and marked variability in the arterial course has been revealed by both imaging and cadaveric studies. This study aimed to verify the previously published information in a large sample and to determine a safe surgical region. Methods We analyzed the three-dimensional time-of-flight magnetic resonance angiography images of 300 individuals. Results The mean distance between the middle meningeal artery and the apex of the condyle or the most medial point of the condyle was 18.8 mm (range: 11.2–25.9 mm) or 14.5 mm (range: 8.8–22.9 mm) respectively. The course of the maxillary artery relative to the lateral pterygoid muscle was medial in 45.7% of cases and lateral in 54.3%. An asymmetric course was evident in 66 patients (22%). The mean distance between the maxillary artery and condylar process at the deepest point of the mandibular notch was 6.2 mm in sides exhibiting a medial course (range: 3.7–9.8 mm) and 6.6 mm in sides exhibiting a lateral course (range: 3.9–10.4 mm). The distances were significantly influenced by age, gender, and the course of the maxillary artery. Conclusion Our study emphasizes the marked inter- and intra-individual variability of the maxillary and middle meningeal arterial courses. We confirmed the proximity of the arteries to the condylar process. Extensive surgical experience and thorough preparation for each individual case are essential to prevent iatrogenic vascular injury.

scholarly journals Interactions between Tandem Cylinders in an Open Channel: Impact on Mean and Turbulent Flow Characteristics

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1718
Author(s):  
Hasan Zobeyer ◽  
Abul B. M. Baki ◽  
Saika Nowshin Nowrin
Keyword(s):  
Turbulent Flow ◽  
Open Channel ◽  
Recirculation Zone ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Flow Recirculation ◽  
Tandem Cylinders ◽  
Flow Development ◽  
The Mean ◽  
Recirculation Length

The flow hydrodynamics around a single cylinder differ significantly from the flow fields around two cylinders in a tandem or side-by-side arrangement. In this study, the experimental results on the mean and turbulence characteristics of flow generated by a pair of cylinders placed in tandem in an open-channel flume are presented. An acoustic Doppler velocimeter (ADV) was used to measure the instantaneous three-dimensional velocity components. This study investigated the effect of cylinder spacing at 3D, 6D, and 9D (center to center) distances on the mean and turbulent flow profiles and the distribution of near-bed shear stress behind the tandem cylinders in the plane of symmetry, where D is the cylinder diameter. The results revealed that the downstream cylinder influenced the flow development between cylinders (i.e., midstream) with 3D, 6D, and 9D spacing. However, the downstream cylinder controlled the flow recirculation length midstream for the 3D distance and showed zero interruption in the 6D and 9D distances. The peak of the turbulent metrics generally occurred near the end of the recirculation zone in all scenarios.

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