Computer based methodology for construction of orthodontic arch wire templates

This paper presents the details and logic of two Fortran computer programs. The program, BRACKET, is designed to evaluate the constant relationship among teeth and orthodontic brackets to which an arch wire is adapted. The program, WIRE, is used to initially fit brackets to teeth using the constants derived in BRACKETS, based upon a series of orthogonal transformations. Subsequently, an orthodontic arch wire is fitted through the brackets, and the results are displayed using computer graphics. It is anticipated that the system would be useful in the orthodontic clinical setting as an aid in arch wire formation. The graphics produce a template which incorporates essential points to consider in arch wire formation, namely, perimeter length, lateral widths, symmetry, and appropriate arch form for the patient.     

Finite element modeling of superelastic nickel–titanium orthodontic wires

Thanks to its good corrosion resistance and biocompatibility, superelastic Ni–Ti wire alloys have been successfully used in orthodontic treatment. Therefore, it is important to quantify and evaluate the level of orthodontic force applied to the bracket and teeth in order to achieve tooth movement. In this study, three dimensional finite element models with a Gibbs-potential-based-formulation and thermodynamic principles were used. The aim was to evaluate the influence of possible intraoral temperature differences on the forces exerted by NiTi orthodontic arch wires with different cross sectional shapes and sizes. The prediction made by this phenomenological model, for superelastic tensile and bending tests, shows good agreement with the experimental data. A bending test is simulated to study the force variation of an orthodontic NiTi arch wire when it loaded up to the deflection of 3 mm, for this task one half of the arch wire and the 3 adjacent brackets were modeled. The results showed that the stress required for the martensite transformation increases with the increase of cross-sectional dimensions and temperature. Associated with this increase in stress, the plateau of this transformation becomes steeper. In addition, the area of the mechanical hysteresis, measured as the difference between the forces of the upper and lower plateau, increases.     

成年人个别牙早失伴错(牙合)畸形修复前正畸治疗的临床观察

目的:探讨成年人个别牙缺失伴错牙合患者,通过正畸治疗校正错牙合后,修复治疗的疗效情况。方法:对16例成年人个别牙缺失致前牙散在间隙或伴有反牙合患者,采用直丝弓矫治技术进行修复前正畸治疗。结果:16例成年人个别牙缺失伴错牙合畸形的患者经过修复前正畸治疗后,再进行牙列缺损修复治疗,获得了令患者较为满意的疗效,外貌也得到了改善。结论:通过正畸、修复相结合的口腔综合治疗,可以有效地使便利体获得更加完善的口腔功能及美观效果。     

Quantitative approach for the prediction of tooth movement during orthodontic treatment

The orthodontic treatment is aimed to displace and/or rotate the teeth to obtain the functionally correct occlusion and the best aesthetics and consists in applying forces and/or couples to tooth crowns. The applied loads are generated by the elastic recovery of metallic wires linked to the tooth crowns by brackets. These loads generate a stress state into the periodontal ligament and hence, in the alveolar bone, causing the bone remodeling responsible for the tooth movement. The orthodontic appliance is usually designed on the basis of the clinical experience of the orthodontist. In this work, a quantitative approach for the prediction of the tooth movement is presented that has been developed as a first step to build up a computer tool to aid the orthodontist in designing the orthodontic appliance. The model calculates the tooth movement through time with respect to a fixed Cartesian frame located in the middle of the dental arch. The user interface panel has been designed to allow the orthodontist to manage the standard geometrical references and parameters usually adopted to design the treatment. Simulations of specific cases are reported for which the parameters of the model are selected in order to reproduce forecasts of tooth movement matching data published in experimental works.     

Quantitative Approach for the Prediction of Tooth Movement During Orthodontic Treatment

The orthodontic treatment is aimed to displace and/or rotate the teeth to obtain the functionally correct occlusion and the best aesthetics and consists in applying forces and/or couples to tooth crowns. The applied loads are generated by the elastic recovery of metallic wires linked to the tooth crowns by brackets. These loads generate a stress state into the periodontal ligament and hence, in the alveolar bone, causing the bone remodeling responsible for the tooth movement. The orthodontic appliance is usually designed on the basis of the clinical experience of the orthodontist. In this work, a quantitative approach for the prediction of the tooth movement is presented that has been developed as a first step to build up a computer tool to aid the orthodontist in designing the orthodontic appliance. The model calculates the tooth movement through time with respect to a fixed Cartesian frame located in the middle of the dental arch. The user interface panel has been designed to allow the orthodontist to manage the standard geometrical references and parameters usually adopted to design the treatment. Simulations of specific cases are reported for which the parameters of the model are selected in order to reproduce forecasts of tooth movement matching data published in experimental works.     

A computer program for the analysis of dental arch form using the cubic spline function.

This paper presents the details and logic of a FORTRAN computer program which fits a cubic interpolatory spline to a set of data points digitized from an exact size photographic reproduction of a dental model. It also measures the length of the arc and computes a set of normals to the curve to be used in evaluating the error in the fit of the spline. The program is used in studies of dental arch form and is useful in evaluating changes in the form of the arches due to orthodontic treatment. The measurement of the arc length provides an adequate assessment of space available in the dental arch, which is of importance to the orthodontist.     

A computer program for the analysis of dental models.

This paper presents the details and logic of a Fortran computer program which carries out routine clinical analysis of dental models resulting from impressions of the teeth and related structures, which are subsequently cast in plaster of Paris. The program is primarily intended for use by the orthodontist who is engaged in research or clinical practice, and is useful in studies related to changes in the dentition as a result of orthodontic treatment.     

Measuring system for in vivo recording of force systems in orthodontic treatment-concept and analysis of accuracy

The aim of our developments is three-dimensional in vivo recording of those orthodontic force systems inducing tooth movements during treatment with fixed appliances. The concept presented here is the first to permit the forces and torques of these statically multiply undetermined systems to be recorded in vivo. For this purpose the force systems transmitted to the teeth from the archwire are isolated from the respective tooth by means of divisible special-design brackets and introduced into a 3D force torque sensor via a gripping appliance. The sensor is fixed with a purpose-developed device relative to the patient's dental arch. The patient's head is positioned relative to the system by means of a bite fork as well as a forehead and chin support. Electrical measurement of the mechanical quantities is carried out by a six-axis force torque sensor with semiconductor strain gauge elements, an electronical evaluator and a mobile measuring computer (PC). Extensive calibration of the sensor system has shown that the measuring uncertainty of the electrical measuring is less than 2%. Precise spatial fixing of bracket slot and archwire in the therapeutic position is crucial to the measuring accuracy of the system, as even minimum displacements affect the force system to be measured. Movements of the measuring system up to 0.04 mm result from a therapeutic force of 1.5 N. The results of extensive in vitro studies have already demonstrated that the system developed by us is suitable for the specified in vivo measuring function.     

MOL3D,a modular and interactive program for molecular modeling and conformational analysis: I — basic modules

MOL3D is a generalized machine-independent computer program that lets the user interactively build 3D structures with different display options, such as wire, ball-and-stick and CPK representations. The program, which uses its own graphics package and driver, is designed to be very user friendly through the use of commands and menus. It has powerful transformation capabilities, such as software rotations, superpositions and zooming, and it is equipped with a fragment database that allows the user to build complex structures. The algorithm presented here is designed to perform computations in all the conformational space and therefore can be used to predict experimentally available quantities, such as NMR coupling constants. The program is efficient in the sense that it handles only dihedral angles in the first steps; as a result, it allows a rapid sampling of a great number of points through the entire conformational space. The user can choose between grid and Monte-Carlo searches of energy minimization, using a reasonable amount of computer time.     

Effects of surface roughness on the coefficients of friction in model orthodontic systems

Orthodontists, like others (Engel, P.A. (1976) Impact Wear of Materials. Elsevier Scientific, New York.), often equate the smoothness of surfaces with the absence of friction. To investigate whether the surface roughness of opposing materials influence the coefficients of friction and ultimately the movement of teeth, arch wires were slid between contact flats to simulate orthodontic arch wire-bracket appliances. From laser specular reflectance measurements, the RMS surface roughness of these arch wires varied from 0.04 microns for stainless steel to 0.23 microns for nickel titanium. Using the same technique, the roughnesses of the contact flats varied from 0.03 microns for the 1 micron lapped stainless steel, to 0.26 microns for the as-received alumina. After each of the arch wire-contact flat couples was placed in a friction tester, fifteen normal forces were systemically applied at 34 degrees C. From plots of the static and kinetic frictional forces vs the normal forces, dry coefficients of friction was obtained that were greater than those reported in the dental literature. The all-stainless steel couples had lower kinetic coefficients (0.120-0.148) than the stainless steel-polycrystalline alumina couple (0.187). When pressed against the various flats, the beta-titanium arch wire (RMS = 0.14 microns) had the highest coefficients of friction (0.445-0.658), although the nickel titanium arch wire was the roughest (RMS = 0.23 microns). Scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) verified that mass transfer of the beta-titanium arch wire occurred by adhesion onto the stainless steel flats or by abrasion from the sharply faceted polycrystalline alumina flats.     

A computer program that simulates cloning of DNA

Easy Cloner is a computer program that manipulates DNA sequences as in cloning experiments and produces maps of the resulting plasmids. The program runs in the graphics mode of an IBM PC or compatible computer and is operated by using a mouse to point to the required actions. The program is available in the public domain.     

Comparison of computer modelling and X-ray results of the binding of a pyrazole derivative to liver alcohol dehydrogenase

The binding to liver alcohol dehydrogenase of the inhibitor 2,4-(4-pyrazolyl)-butylisothiourea has been studied both by modelling experiments using computer graphics with interactive energy minimization and by X-ray crystallographic structure determination. For the modelling experiments, we used the program system TOM, which was developed in our laboratory as an extension of the program FRODO. Different strategies for using computer graphics with interactive energy minimization were tested. Two essentially different binding modes were found. One of these was favoured from energy minimizations using a potential energy function which was the sum of a Coulomb interaction term and two different van der Waals' interaction terms for non-bonded and torsional interactions. This binding mode was close to the crystallographic observed structure. The results show that flexibility of both ligand and receptor side-chains as well as main-chain conformations are important for docking to the active site of liver alcohol dehydrogenase.     

Computer graphics with computerized tomography for functional neurosurgery

A computer graphics technique for computer-assisted stereotactic surgery is presented. The program is designed to aid the surgeon by presenting an on-line graphics display of stereotactic probes and electrodes superimposed on cross sections of the human brain stem. This technique simulates an otherwise blind surgical procedure on a graphics screen for use during surgery. An earlier system based around the DEC MINC-11 BA computer system has been used by the authors for the performance of stereotactic surgery with conventional ventriculography. This system has been upgraded and is now configured about an even more compact microprocessor-based hardware system with expanded graphics capabilities, which also allows its use with computerized tomography.     

PEPCRE: an interactive program to create,manipulate and display oligopeptides

PEPCRE is an interactive computer graphics program for the rapid construction, manipulation and display of oligopeptides. Essentially any desired conformation of an oligopeptide can be constructed in a simple and straightforward manner. The program provides various display and output possibilities. It is user-friendly and is written in FORTRAN 77 for use on inexpensive, monochrome graphics terminals.     

An interactive graphics program for comparing and aligning nucleic acid and amino acid sequences.

This paper describes a computer program designed to look for similarities between pairs of nucleic or amino acid sequences. The program looks both for segments of perfect identity or for regions where, using a scoring matrix, a minimum value is exceeded. The results of comparisons are presented as a matrix which is displayed on a simple graphics terminal. Use of a graphics terminal allows the user to display the whole of the two sequences in one screenful or to home-in on regions of interest to examine them in more detail. The program is interactive and so the user can easily see the effect of changes to variables and can use inbuilt editing functions to make insertions to produce alignments of the two sequences. These aligned sequences can then be saved on disk files for further processing.     

口腔正畸MIA技术对青少年安氏Ⅱ类错[牙合]畸形患者对龈沟液MMP-2表达水平的影响

目的:探讨口腔正畸微螺钉种植体支抗(Microscrew implant anchor,MIA)技术对青少年安氏Ⅱ类错[牙合]畸形患者对龈沟液基质金属蛋白酶(Matrix metalloproteinase,MMP)-2表达水平的影响。方法:2016年1月1日至2019年12月31日选择在本院诊治的青少年安氏Ⅱ类错[牙合]畸形患者86例,根据治疗方法把患者分为MIA组与对照组,各43例,对照组给予头帽口外弓支抗技术结合直丝弓矫治器治疗,MIA组给予MIA技术结合直丝弓矫治器治疗,检测龈沟液MMP-2表达水平变化情况。结果:MIA组正畸后6个月的总有效率为97.7%,显著高于对照组的81.4%(P<0.05)。两组正畸后6个月的SNA角、OB与OJ值低于正畸前,MIA组低于对照组(P<0.05),两组正畸前后SNB角在组内与组间对比差异都无统计学意义(P>0.05)。两组正畸后6个月的龈沟液MMP-2值低于正畸前,MIA组低于对照组(P<0.05)。结论:口腔正畸MIA技术在青少年安氏Ⅱ类错[牙合]畸形患者的应用能抑制龈沟液MMP-2的表达,有利于改善患者的头颅与牙齿的X线指标,从而促进提高治疗效果。     

Comparison of protein structural profiles by interactive computer graphics

This paper describes a novel computer graphics tool for predicting protein structures. The method is based on structural profiles; which are plots of hydrophobicity, parameters used for secondary structure prediction, or other residue-specific traits against sequence number. Similar structural profiles can indicate similar tertiary structures, in the absence of sequence homology. The profiles of reference proteins, with known structure, can be used for prediction. In the method presented here, structural profiles are compared by interactive computer graphics, using the program Multiplot. As a test, a structural profile comparison of several proteins known to have similar 3D structures is presented. Comparison of structural profiles detects similar folding of the two domains of rhodanese, which was not easily detected by sequence homology.     

Cleft lip and palate treated by presurgical orthopedics, gingivoperiosteoplasty, and lip adhesion (POPLA) compared with previous lip adhesion method: a preliminary study of serial dental casts.

Comparing the treatment protocols for cleft lip and palate requires a study of facial growth and development. Serial orthodontic study models aid in delineating the effects of surgery on maxillary mandibular relationships. In 1978, a new protocol, POPLA (presurgical orthopedics followed by periosteoplasty and lip adhesion), was developed and put into practice. This article compares the results obtained using POPLA (group I) with those using the previous method (lip adhesion alone) (group II) for cases of unilateral and bilateral clefts. Complete orthodontic study models were available for 124 patients, 63 in group I and 61 in group II. Specific timing sequences and surgical details are discussed. Dental cast analyses evaluated alveolar gap, arch width, anteroposterior distance, incisor crossbite (single tooth and multiple tooth), and buccal crossbite (single and multiple tooth) at birth and at 3, 6, and 9 years of age. X-ray studies evaluated the bony bridge. Additional comments are made regarding the incidents and effects of pharyngeal flaps and bone grafts on maxillary-mandibular relationships. Results included less buccal crossbite in the POPLA group, with a wider transverse distance of the upper dental arch. There was a greater frequency of anterior crossbite in the POPLA group, and the anteroposterior distance was shorter at 6 years of age but less so by age 9. This may be because of the different orthodontic care received by the patients in the two groups. In conclusion, the POPLA approach achieves the main goal of moving the palate into a normal position and stabilizing the arch with a bony bridge that attracts teeth. It avoids the difficult anterior fistulae and presents a more symmetrical platform upon which the lip can be united and the nose can be corrected early.     

Computer-assisted method for multi-exponential curve fitting for determining cerebral blood flow.

A computer program has been developed for use in determining cerebral blood flow using an inert radioactive gas. The basic algorithm involves the determination of multiple exponential coefficients from the complex concentration-time function. The exponential coefficients are determined by 'peeling' away slower exponentials complex function one at a time. The procedure involves the use of a small laboratory computer in the interactive graphics mode. The method is currently in use analyzing data in a cerebral vascular research laboratory.     

Applications of stem cells in orthodontics and dentofacial orthopedics:Current trends and future perspectives

A simple overview of daily orthodontic practice involves use of brackets, wires and elastomeric modules. However, investigating the underlying effect of orthodontic forces shows various molecular and cellular changes. Also, orthodontics is in close relation with dentofacial orthopedics which involves bone regeneration. In this review current and future applications of stem cells(SCs) in orthodontics and dentofacial orthopedics have been discussed. For craniofacial anomalies, SCs have been applied to regenerate hard tissue(such as treatment of alveolar cleft) and soft tissue(such as treatment of hemifacial macrosomia). Several attempts have been done to reconstruct impaired temporomandibular joint. Also, SCs with or without bone scaffolds and growth factors have been used to regenerate bone following distraction osteogenesis of mandibular bone or maxillary expansion. Current evidence shows that SCs also have potential to be used to regenerate infrabony alveolar defects and move the teeth into regenerated areas. Future application of SCs in orthodontics could involve accelerating tooth movement, regenerating resorbed roots and expanding tooth movement limitations. However, evidence supporting these roles is weak and further studies are required to evaluate the possibility of these ideas.