Extraoral Force Research Articles

An innovative approach for treatment of anterior open bite in Class II Division 1 patient with VF appliance (Zygomatic Implant and Spur Assisted) - A case report

Controlling anchorage is one of the foremost necessary aspects of treatment. Moderate anchorage is comparatively simple to manage with the use of some intraoral appliances and biomechanical procedures. On the opposite hand, cases that need the most anchorage need extraoral support to strengthen the anchorage. In some instances, 100 percent anchorage has got to be maintained, such an anchorage may be termed as absolute anchorage. It's tough and not possible to get absolute anchorage by using typical ways like extraoral force application. In this case report, we describe the treatment of Open bite by using the support of Zygomatic plates and Spurs anteriorly placed with the combination of posterior bite blocks. A 20-year-old female reported to our department of orthodontics with the chief complaint of anteriorly placed upper front teeth. There was no relevant medical history; she was having tongue thrusting habit, acute nasolabial angle and incompetent lips. Overjet of 12mm and anterior skeletal open bite from canine to canine of 5mm was present associated with anterior tongue thrusting habit, and constricted upper arch. The molar relation was end-on on the right side and class II on left side. Canine relation is end-on, on both the side. Growth pattern is vertical. Upper arch is well aligned with constriction in premolar region; lower arch has crowding of 6 mm. The treatment plan was selected as alignment of the teeth with fixed mechanotherapy and impaction of the maxillary posteriors using zygomatic anchorage with posterior bite block and spurs soldered to the anterior part of the appliance. The sutures were removed after 7 days, the appliance was inserted into the patient’s mouth and secured with a power chain to the hooks of the appliance and the hook of zygomatic implant, 400gms of force was applied on both the sides.

An innovative approach for treatment of anterior open bite in Class II division 1 patient with zygomatic implant and spur assisted appliance - A case report

Controlling anchorage is one of the foremost necessary aspects of treatment. Moderate anchorage is comparatively simple to manage with the use of some intraoral appliances and biomechanical procedures. On the opposite hand, cases that need the most anchorage need extraoral support to strengthen the anchorage. In some instances, 100 percent anchorage has got to be maintained, such an anchorage may be termed as absolute anchorage. It's tough and not possible to get absolute anchorage by using typical ways like extraoral force application. In this case report, we describe the treatment of Open bite by using the support of Zygomatic plates and Spurs anteriorly placed with the combination of posterior bite blocks.A 20-year-old female reported to our department of orthodontics with the chief complaint of anteriorly placed upper front teeth. There was no relevant medical history; she was having tongue thrusting habit, acute nasolabial angle and incompetent lips. Overjet of 12mm and anterior skeletal open bite from canine to canine of 5mm was present associated with anterior tongue thrusting habit, and constricted upper arch. The molar relation was end-on on the right side and class II on left side. Canine relation is end-on, on both the side. Growth pattern is vertical. Upper arch is well aligned with constriction in premolar region; lower arch has crowding of 6 mm. The treatment plan was selected as alignment of the teeth with fixed mechanotherapy and impaction of the maxillary posteriors using zygomatic anchorage with posterior bite block and spurs soldered to the anterior part of the appliance. The sutures were removed after 7 days, the appliance was into the patient’s mouth and secured with a power chain to the hooks of the appliance and the hook of zygomatic implant, 400gms of force was applied on both the sides.

Does Early Treatment Improve Clinical Outcome of Class II Patients? A Retrospective Study.

The present study was carried out to evaluate the benefits from one-phase Class II Early Treatment (ET) using extraoral forces and functional appliances but without intermaxillary forces and eventual lower leeway space preservation compared to two-phase Class II Late Treatment (LT) with the need for extractions and full fixed appliances as well as lower incisor proclination. The ET group (n = 239, 115 M, 124 F, mean age 10.6 ± 1.2 years), with first premolars not in contact and the second deciduous lower molars preserved, was compared to the LT group (n = 288, 137 M, 151 F, mean age 12.4 ± 1.5 years). The ET group was first treated with headgears, growth guide appliances, or Teuscher activators and, in borderline crowding cases, with lower space maintenance by a lingual arch, lip bumper, or fixed utility arch. The LT group and the second phase of ET were treated with full fixed appliances including intermaxillary forces such as Class II elastics or noncompliance devices; headgear and a growth guide appliance were also used. Cephalograms and plaster models were taken before (T1) and after treatment (T2) to calculate cephalometric changes and space balance discrepancies. The differences between T1 and T2 were analyzed by a t-test for normally distributed data and by the Mann–Whitney Test for nonnormally distributed data at a level of p < 0.05. The groups were defined as statistically homogeneous at T1. A statistical analysis showed that the ET group (mean treatment time 35.3 ± 13.3 months) was significantly associated with a 22.2% lower extraction rate, 15.9% less need for a full fixed appliance, and more than 5° less incisor proclination in the nonextraction cases compared to the LT group (mean treatment time 25.9 ± 8.1 months); treatment time significantly increased in the ET group compared to the LT group. Early Class II treatment resulted in a significant treatment effort reduction in more than one third of the patients and less lower incisor proclination, even if it clinically increased treatment time.

Biomechanical effects of Teuscher activator in hyperdivergent Class II malocclusion treatment: A finite element analysis

BackgroundIn orthodontic treatment, the combination of an activator with a headgear is commonly used in treatment of the hyperdivergent Class II malocclusion. However, the distribution of stresses transmitted to the maxilla by these appliances has been little studied. This study aimed to compare the biomechanical effects of stresses transmitted to the maxilla and teeth by a Teuscher activator (TA) for different lines of action of extraoral force, using finite element analysis. Material and MethodsA tridimensional finite element model of the maxilla and teeth was created based on the true geometry of a human skull. The (TA) and the face bow were designed in 3D computer-aided design and fixed in the maxilla model. To study the effects of mechanical stress transmitted to the maxilla in the treatment of hyperdivergent Class II malocclusion with (TA) combined with extraoral forces, five different finite element models were used, considering the centers of resistance of the maxilla and dentition. ResultsThe results showed that stresses increased progressively when the force line of action moved in posteroanterior direction. Von Mises equivalent stress was lower in Model 1 (0°) than in Model 5 (60°). In Models 1 (0°) and 2 (15°), molars suffered greater distal displacement and incisors showed extrusion. In Model 3 (30°), the force line of action promoted a distal displacement of molars and incisors. In Models 4 (45°) and 5 (60°), the whole maxillary anterior sector showed counterclockwise displacement. ConclusionsDifferent force lines of action influence the intensity and distribution of orthodontic and orthopedic forces in the maxilla. The extraoral force’s line of action used in Model 3 (30°) is the most compatible with the objectives of the hyperdivergent Class II malocclusion treatment in growing patients. Key words:Class II, Headgear, Early treatment, FEA.

The activator and its modification - A review

Introduction: Functional appliance are different varieties of appliances fabricated mainly to correct skeletal class II by enhancing mandibular growth. Functional appliances are mainly intraoral to which extraoral forces can be attached (headgear).There are number of functional appliances used such as activator, bionator, twin block appliance, Frankel’s regulators etc. The activator, designed by Andresen and Haupl, was fabricated to advance the mandible by several millimetres for correction of class II malocclusion. The appliance was loosely fitted so that the patient could hold the appliance in position actively (by muscle activity or by functioning). The activator was modified by many practitioners to be used in different situation, depending on the cases. This review will emphasize on the activator and its derivatives as it was the first functional appliance to be widely accepted. Conclusion: The activator could be considered as an alternative within a modern orthodontic practice for correction of skeletal malocclusion in growing childrens. The success of the appliance totally depends on the patient compliance, orthodontist should consider this before planning for an activator (conventional activator- due to its Bulkiness), modified activators can be a better option in such situations. Keywords: Functional appliance, Activator, Modified activators, Skeletal malocclusion.

Use of the extraoral arch in the correction of class II, division 2, type C malocclusion

Para el tratamiento de una maloclusion clase II division 1 hay muchos enfoques, como fuerzas extraorales, aparatos de pendulo, cirugia ortognatica y extracciones de premolares. En este articulo presentamos las fuerzas extraorales y el caso de un paciente con una maloclusion clase II division 1 severa, tratado mediante traccion occipital. Los resultados muestran la eficacia del tratamiento. Hay un cambio en el perfil del paciente, over jet y las relaciones molares/caninas. (Kiru 2011, 8: 99-104).

Stress distribution in maxillary first molar periodontium using straight pull headgear with vertical and horizontal tubes: A finite element analysis.

Background:One of the most effective ways for distal movement of molars to treat Class II malocclusion is using extraoral force through a headgear device. The purpose of this study was the comparison of stress distribution in maxillary first molar periodontium using straight pull headgear in vertical and horizontal tubes through finite element method.Materials and Methods:Based on the real geometry model, a basic model of the first molar and maxillary bone was obtained using three-dimensional imaging of the skull. After the geometric modeling of periodontium components through CATIA software and the definition of mechanical properties and element classification, a force of 150 g for each headgear was defined in ABAQUS software. Consequently, Von Mises and Principal stresses were evaluated. The statistical analysis was performed using T-paired and Wilcoxon nonparametric tests.Results:Extension of areas with Von Mises and Principal stresses utilizing straight pull headgear with a vertical tube was not different from that of using a horizontal tube, but the numerical value of the Von Mises stress in the vertical tube was significantly reduced (P < 0/05). On the other hand, the difference of the principal stress between both tubes was not significant (P > 0/05).Conclusion:Based on the results, when force applied to the straight pull headgear with a vertical tube, Von Mises stress was reduced significantly in comparison with the horizontal tube. Therefore, to correct the mesiolingual movement of the maxillary first molar, vertical headgear tube is recommended.

Treatment of a severe class II div I malocclusion using J-hook headgear

This case report describes 3-year follow-up of orthodontic treatment of a patient with Class II div 1 malocclusion who have 11 mm of overjet and 5 mm of overbite. Extractions of maxillary first and mandibular second premolars were carried out. Maxillary anteriors were retracted using extra-oral force in the form of J-hook headgear. Simple biomechanical principles were utilized for achieving normal occlusion and facial balance.

Long‐term changes in microbiology and clinical periodontal variables after completion of fixed orthodontic appliances

The aim of this prospective study was to monitor patients' microbiological and clinical periodontal parameters prior and up to 2 years after orthodontic treatment. Twenty-four adolescents were treated with brackets. Fourteen of them received bands on upper first molars for extra-oral force application before bonding brackets to the remaining teeth. Microbiology, periodontal probing depth, bleeding on probing (BOP), and gingival crevicular fluid (GCF) flow were assessed at baseline (T1), bracket removal (T2), and 2 years post-treatment (T3). A statistical comparison was made over time and between bands and brackets. A significant increase from T1 to T2 and a decrease from T2 to T3 in pathogenicity of plaque were noted. No significant difference was observed concerning supragingival colony-forming units (CFU) ratio (aerobe/anaerobe) between T3 and T1. However, the subgingival CFU ratio (aerobe/anaerobe) at T3 did significantly differ from the ratio at T1. Periodontal probing depth, BOP and GCF flow showed a significant increase between T1 and T2 and a reduction between T2 and T3, resulting in the absence of significant differences between T3 and T1, except for BOP at banded sites. Placement of fixed appliances has an impact on periodontal parameters. The results showed that not all parameters were normalized at T3, indicating that the changes are only partially reversible.

Force Monitoring in a Maxilla Model and Dentition Using Optical Fiber Bragg Gratings

The aim of this work is to show the possibility of using fiber optic sensors to instrument inside parts of an artificial maxilla and measure internal tension transmitted by the orthodontic and orthopedic appliances to the dentition and the adjacent bone. Bragg gratings written in a standard optical fiber were used to monitor the maxillary teeth and a multiplexed fiber was used to monitor the surface of the maxillary bone, transversally to the longest axis of the teeth. A Universal Test Machine was used to evaluate the sensitivity of the sensor to the vertical and lateral forces applied on the teeth. A wavelength shift of approximately 0.30 nm was detected when applying loads ranging from 0 to 20 N. By applying forces using the standard orthodontic appliances installed on the dentition it was possible to detect a range of forces between 0.025 N to 0.035 N during the activation of the arch wire and extra-oral forces. The use of the internal sensors in an artificial model made possible the monitoring of the resulting forces on the internal parts of the teeth and at the position where the strain takes place within the maxilla. The sensors detected that the orthodontic forces were not transmitted to the surface of the maxilla. This information is important to elucidate and to correlate undesirable effects as tooth root absorption and local pain during the orthodontic treatment.

"Growth modulation with fixed mechanotherapy: Use of extra-oral forces"

Controversies about early orthodontie treatment, particularly Class II, Division 1 malocclusion, revolve about modalities and timing of treatment. The most critical issue regarding methods of treatment has been the capability to affect facial growth. The claim that functional appliances may stimulate mandibular growth has shaped the nature of the debate on the interaction between treatment and growth. The argument on timing of early treatment involves intervention not only in various stages of dentitions but also in the modality of treatment. The present case takes into consideration the age of the patient, the innate growth potential and the best of the effects trom the straight-wire appliance (S WAJ as well as the extra-oral forces. The positive motivation of the patient, undoubtedly plays a crucial role. The conventional therapy by using extra-oral forces are beneficiai provided the forces are controlled lest they may lead to root resorption and further compilations.

Quantitative Digital Subtraction Radiography in the Assessment of External Apical Root Resorption Induced by Orthodontic Therapy: A Retrospective Study

The objective of this study was to evaluate density changes around the apices of teeth during orthodontic treatment by using digital subtraction radiography to measure the densities around six teeth (maxilla central incisors, lateral incisors, and canines) before and after orthodontic treatment in 36 patients and also assess treatment variables and their coorelation with root resorption. A total of 36 consecutive patient files were selected initially. The selected patients presented with a class I or II relationship and were treated with or without premolar extractions and fixed appliances. Some class II patients were treated additionally with extraoral forces or functional appliances. External apical root resorption (EARR) per tooth in millimeters was calculated and was also expressed as a percentage of the original root length. Image reconstruction and subtraction were performed using the software Regeemy Image Registration and Mosaicing (version 0.2.43-RCB, DPI-INPE, Sao Jose dos Campos, Sao Paulo, Brazil) by a single operator. A region of interest (ROI) was defined in the apical third of the root and density calibration was made in Image J® using enamel (gray value = 255) as reference in the same image. The mean gray values in the ROIs were reflective of the change in the density values between the two images. The root resorption of the tooth and the factors of malocclusion were analyzed with a one-way ANOVA. An independent t-test was performed to compare the mean amount of resorption between male and female, between extraction and nonextraction cases. The density changes after orthodontic treatment were analyzed using the Wilcoxon signedrank test. In addition, the density changes in different teeth were analyzed using the Kruskal-Wallis test. The cut-off for statistical significance was a p-value of 0.05. All the statistical analyses were carried out using SPSS (version 13.0 for Windows, Chicago, IL, USA). Gender, the age at which treatment was started and Angle's classification was not statistically related with observed root resorption. The mean percentage density reduction as assessed by DSR was greatest in both central incisor: by 27.2 and 25.2% in the upper-right and upper-left central incisors, respectively, followed by the upper-right and upper-left canine teeth (23.5 and 21.0%) and then the upper-right and upper-left lateral incisors (19.1 and 17.4%). Tooth extraction prior to treatment initiation and the duration of orthodontic treatment was positively correlated with the amount of root resorption. DSR is useful for evaluating density changes around teeth during orthodontic treatment. The density around the apices of teeth reduced significantly after the application of orthodontic forces during treatment. Assessment of density changes on treatment radiographs of patients undergoing orthodontic therapy may help in the monitoring of external apical root resorption during course of treatment.

Análise do movimento inicial de molares superiores submetidos a forças extrabucais: estudo 3D

OBJETIVO: analisar pelo método dos elementos finitos o deslocamento dos molares superiores frente a três diferentes inclinações do arco externo do aparelho extrabucal na tração do tipo cervical. MÉTODOS: maxila, dentes montados em má oclusão de Classe II e aparelho foram modelados através de formulação variacional e seus valores reproduzidos em coordenadas X, Y e Z. Foram realizadas simulações em microcomputador tipo PC, utilizando o programa ANSYS versão 8.1. Cada modelo de arco externo reproduziu linhas de força que passaram (1) acima (AcCR), (2) abaixo (AbCR) e (3) no centro de resistência (CR) do molar permanente superior de um mesmo modelo portador de má oclusão de Classe II. A avaliação restringiu-se ao movimento inicial dos molares frente à força extrabucal de 4 Newtons. RESULTADOS: o movimento distal inicial dos molares, tendo como ponto de referência a mesial do tubo, foi maior na coroa do modelo AbCR (0,47x10-6), e maior na raiz do modelo AcCR (0,32x10-6), provocando inclinações da coroa para distal e mesial, respectivamente. No modelo CR, os pontos na coroa (0,15x10-6) e raiz (0,12x10-6) deslocaram-se para distal equilibradamente, resultando em movimento de translação. Em todos os modelos, numa vista oclusal, houve tendência de rotação distal inicial da coroa, porém no modelo CR esse movimento foi muito pequeno. No sentido vertical (Z), todos os modelos revelaram movimento extrusivo (AbCR= 0,18x10-6; CR= 0,62x10-6; AcCR= 0,72x10-6). CONCLUSÃO: a simulação computacional do uso de aparelho extrabucal com tração cervical revelou a ocorrência de movimento extrusivo e distal, podendo ser por inclinação distal de coroa, de raiz ou movimento de translação.

Conséquences esthétiques du traitement de la classe II : étude comparative Distal Active Concept (DAC)/Forces Extra-Buccales (FEB)

In the past orthodontists frequently used extra-oral force to slow down skeletal growth in their treatment of Class II malocclusions; more modern practice relies less on applying distal force to the maxilla than on stimulating forward growth of the mandible. Does this change in therapeutic design have any repercussions in facial esthetics? To evaluate the impact of treatment on the appearance of the profile, we conducted a study with 64 patients in the adolescent dentition stage with a Class II, division 1 malocclusions. None had teeth extracted or preliminary orthodontic treatment. We divided them into two sections; we treated the first group of 33 patients with the Distal Active Concept (DAC), which encourages forward movement and growth of the mandible, and we treated the second group of 31 patients with Extra-Oral Force (EOF) in combination with a full-banded appliance. Comparing the results with cephalometric profile analyses, we found that the soft tissue contour of the lower part of the face showed considerably more sagittal development in the children treated by DAC than those treated by EOF.

Success of Zygomatic Plate-Screw Anchorage System

To evaluate the success of zygomatic plate-screw anchorage and to define the key points that help to improve the success of this system. A total of 74 zygomatic plate-screw anchors were applied to 37 patients from 2 groups receiving orthodontic treatment. The first group consisted of 19 patients, and the zygoma anchors were applied bilaterally to distalize the maxillary buccal segment. The second group consisted of 18 patients, and the zygoma anchors were applied bilaterally to stabilize the maxillary molars during maxillary canine retraction. The orthodontic force was applied 1 week after the insertion of the plates. In the first group, 450 g of direct force and in the second group 150 g of indirect force were applied to the zygomatic plates. The success rate of the zygomatic plate-screw anchorage system was evaluated. One plate was lost and the others remained stable all through the orthodontic treatment. Mild gingival inflammation was observed in 1 patient (2 plates), and pus formation was detected in 1 patient (2 plates). One plate was covered because of mucosal hypertrophy. Zygomatic plate-screw anchorage system is a reliable technique to obtain orthodontic anchorage and may eliminate the need for extraoral force. However, the surgical insertion technique, position of the plates, and oral hygiene status of the patients certainly influence the success of the system.

L’orthodontie linguale à l’ère d’un nouveau mode de traitement incorporant des critères occlusaux et esthétiques

There has been remarkable progress in the field of orthodontics with the advent of CAD/CAM technology since the beginning of the 21st century. In lingual orthodontics, brackets designed and manufactured with a CAD/CAM system [1] are now available to produce more efficient tooth movement with reduced frictional resistance. The use of implant anchors for absolute anchorage has eliminated the need for excessive tipping of the molars with anchorage bends, which compromises periodontal health, as well as the need for application of heavy extraoral forces, thus providing more reasonable treatment options for both the patient and orthodontist.

Orthodontic treatment of patients with sickle-cell anemia.

Sickle-cell anemia is a genetic blood disease characterized by a hemoglobin gene mutation. The genetic failure is basically constituted by replacement of the hemoglobin beta chain in the sixth position so that the amino acid valine is encoded instead of glutamic acid. As a result, the erythrocytes have their normal biconcave discoid shape distorted, generally presenting a sicklelike shape, which reduces both their plasticity and lifetime. Because a complete blood supply is so important during application of both intraoral and extraoral forces, this article addresses the general and oral aspects associated with sickle-cell anemia. This will guide the clinician regarding such patients who seek orthodontic treatment by making references to literature on multidisciplinary management.

The Use of Intraosseous Screw for Upper Molar Distalization: A Case Report

The use of implants has made a major change in orthodontic treatment mechanics. They have replaced conventional unaesthetic and compliance dependent extraoral appliances with well accepted intraoral mechanics. Implants can be used in molar and canine distalization, intrusion and in extraoral force applications. In the present case report, treatment of a case using an intermaxillary fixation screw (IMF) will be presented. The treatment results will be evaluated using pretreatment, post distalization and post treatment cephalometric radiographs and dental casts.

Molar distalizer with nickel-titanium pistons. A case presentation.

Various devices have been used to distalize upper molars on class II malocclusion patients. It has been noted that most of those devices tend to incline and rotate first molars’ crowns, because of the force applied on them. This presentation introduces a fixed device that is able to move distally upper molars with reduced rotation or distal inclination. Therefore, the use of extra-oral forces would be minimized. Constant low intensity forces applied by the nickel titanium’s open spring piston optimizes movement and decreases treatment time. Another advantage of this specific device is the fact, that it is bonded, so patient’s high degree of cooperation is no a requirement for upper molars distalization treatments.

Evaluation of the changes in midfacial configuration after face mask therapy in skeletal Class III growing patients by morphometric analysis techniques.

The prevalence of Angle Class III malocclusion is relatively high in Taiwan. For children who suffer from maxillary retrognathia, face mask therapy is a promising treatment modality. The purpose of this study was to evaluate the changes in midfacial configuration after face mask therapy in skeletal Class III growing patients by morphometric analysis techniques. Thirty children who had been treated with face masks were compared with a group of 30 gender-matched, age-matched, observation period-matched, and craniofacial configuration-matched subjects with untreated Class III malocclusions. Average geometries, scaled to an equivalent size, were generated by means of Procrustes analysis. Graphical analysis, utilizing thin-plate spline analysis and strain tensor methods, was performed for localization of differences in shape and size changes. Maximum and minimum principal extensions were drawn to express the directions of shape change. Maxillary protraction-induced changes resulted from a combination of both orthopedic and dental effects. A significant increase in size (7.7% to 9.9%) was noted at the supero-anterior region of the midfacial configuration (rhinion-orbitale-midpalatal point-anterior nasal spine) when subjected to an extraoral traction force; 7.7% to 12.1% of increase in size and 14.4% to 33.4% of change in shape were found at the anterior portion of the maxillary alveolar bone. The directions and amount of principal strain tensors could express the magnitudes and directions of morphological changes within the midfacial complex in an efficient way. We conclude that morphometric analysis techniques can be used to evaluate the changes in midfacial configuration after face mask therapy and can provide a valuable supplement for conventional cephalometric analysis.