Effects of Class II treatment with a banded Herbst appliance on root lengths in the posterior dentition.

INTRODUCTION: The aim of this study was a retrospective analysis of posterior teeth in 20 adolescents and young adults with Angle Class II Division 1 malocclusion treated with a banded Herbst appliance to check for inhibited root development and apical root resorption. METHODS: Panoramic radiographs were taken of every patient at the beginning and after the completion of functional orthopedic treatment. The magnification of the area of the posterior teeth was determined individually for every radiograph. Then the vestibular lengths of the molars and premolars were assessed metrically. To assess root-length changes, the difference between the lengths of the teeth before and after treatment was calculated. RESULTS: After treatment with a banded Herbst appliance, tooth length generally increased in the area of the anchorage. But there was a tendency toward root-length decrease in teeth immediately adjacent to the Herbst fittings in the vestibular roots of both the maxillary first molars (distovestibular, -0.02 ± 2.31 mm; mesiovestibular, -0.06 ± 2.05 mm) and the mandibular first premolars (-0.46 ± 3.53 mm). CONCLUSIONS: The banded Herbst appliance might deliver unphysiologic forces to immediate anchor teeth, thereby exposing these to a higher risk of root resorption than in other teeth incorporated into the anchorage either directly via bands or indirectly via occlusal or approximal contacts. Looking at uncompromised root morphology in the area of the anchorage, we believe that early treatment with fixed functional appliances can be predicted to yield better outcomes than late treatment because of the higher biologic tolerance expressed by teeth with an apical latency.

Class II treatment with fixed functional orthodontic appliances before and after the pubertal growth peak - a cephalometric study to evaluate differential therapeutic effects.

OBJECTIVE: The aim of this clinical trial was to investigate and compare outcomes after treating a skeletal Class II malocclusion with two fixed functional orthodontic appliances, the Herbst appliance and the Functional Mandibular Advancer, by evaluating their skeletal and dentoalveolar effects and the repercussion on the profile in relation to patient age. PATIENTS AND METHODS: The sample population comprised 42 subjects with skeletal Class II malocclusion. They were divided into two groups depending on age. Group A (n = 21) included nine female subjects aged up to 12 years and twelve male subjects aged up to 14 years. Group B (n = 21) comprised twelve females older than 12 years and nine males older than 14 years. Treatment course was documented cephalometricly. The net therapeutic effects were calculated with reference to the control group. RESULTS: A significant reduction of the overjet was achieved in both treatment groups. Within the two groups there were no significant sagittal effects in terms of mandibular advancement. However, there was an inhibiting effect on the maxilla, which counteracted the natural growth process. Significant changes in vertical direction were detected mainly in the younger patients in the sense of lengthening of the lower face. Significant dental changes were predominantly found in the group of older patients. For instance, treatment with fixed functional orthodontic appliances led to retrusion of the upper incisors by a mean of 2.21 mm +/- 2.66 mm (p = 0.0015), protrusion of the lower incisors by a mean of 2.28 mm +/- 2.39 mm (p =

Efficiency of a skeletonized distal jet appliance supported by miniscrew anchorage for noncompliance maxillary molar distalization.

INTRODUCTION: Conventional anchorage appliances rely exclusively on intraoral anchorage for noncompliance molar distalization. The partial coverage of the palate, in particular, often results in compromised oral hygiene. An innovative alternative combines a skeletonized distal jet appliance with 2 paramedian miniscrews for additional anchorage. The objectives of this study were to investigate the suitability of the skeletonized distal jet for translatory molar distalization and to check the quality of the supporting anchorage setup. METHODS: Two paramedian miniscrews (length, 8-9 mm; diameter, 1.6 mm) were placed into the anterior area of the palate in 10 patients. Skeletonized distal jet appliances fitted with composite to the first premolars and the collars of the miniscrews were used for bilateral molar distalization, and the coil springs were activated with a distalization force of 200 cN on each side. RESULTS: The study confirmed the suitability of the appliance for translatory molar distalization (3.92 +/- 0.53 mm) with slight mesial inward rotation (on average, 8.35 degrees +/- 7.66 degrees and 7.88 degrees +/- 5.50 degrees ). The forces acting reciprocally on the anchorage setup were largely absorbed by the anchorage unit involving 2 anchorage teeth and 2 miniscrews. Significant anchorage loss, in the form of first premolar mesialization of 0.72 +/- 0.78 mm, was found. CONCLUSIONS: The skeletonized distal jet appliance supported by additional miniscrew anchorage allows translatory molar distalization. Although the anchorage design combining 2 miniscrews at a paramedian location and the periodontium of 2 anchorage teeth does not offer the quality of stationary anchorage, it achieves greater molar distalization in total sagittal movement than conventional anchorage designs with an acrylic button.

Treatment effects of intraoral appliances with conventional anchorage designs for non-compliance maxillary molar distalization: a literature review.

Since the end of the 1970s, various appliances with intramaxillary anchorage for distalization of the upper molars have been described as an alternative to headgear. The major advantages of these innovative appliances are that they act permanently and are independent of patient compliance. The purpose of this study was to compare the efficiency, both quantitatively and qualitatively, of various appliance types with intramaxillary anchorage for non-compliance molar distalization. Eighty-five papers were reviewed, and 22 were identified as being suitable for inclusion. The selection was based on compliance with the following criteria: treatment group with at least 10 non-syndromal patients, conventional intraoral anchorage design using a palatal button and anchorage teeth, consistent cephalometric measurements in clinical-epidemiological studies, exact data on the course of treatment, and statistical presentation of the measured outcomes and their standard deviations. The results show that non-compliance molar distalization is possible with numerous different appliances. While molar distalization with standard pendulum appliances exhibited the largest values for dental-linear distalization, it also resulted in concurrent, substantial therapeutically undesirable distal tipping. However, specific modifications to the pendulum appliance allow achievement of almost bodily molar distalization. Different outcomes are quoted in the studies for the efficiency of loaded spring systems for distal molar movement, but it seems that the first class appliance and the palatal distal jet are more efficient than the vestibular Jones Jig. The studies identify anchorage loss as being found in the area of the incisors rather than the area of the first premolars. There was a trend for more substantial reciprocal side-effects to occur when only two teeth were included in the anchorage unit. Vertical components acting on the molars, premolars, and incisors, such as intrusion and extrusion, tended to be of secondary importance and, therefore, may be disregarded.

Biomechanics of a Distal Jet appliance. Theoretical considerations and in vitro analysis of force systems.

OBJECTIVE: To analyze the forces and moments acting in the first molar region, induced by the Distal Jet appliance for maxillary molar distalization. MATERIALS AND METHODS: Over a working section of 3 mm with reactivation of the loaded spring systems, the force systems of three laboratory-fabricated appliances of identical design were analyzed with a 3D metering device. RESULTS: The force systems registered in vitro exhibited complex biomechanics. Regular reactivation of the loaded coils resulted in consistent distalizing forces and uprighting moments, in forces and moments toward buccal as well as slightly intrusive forces, and mesial-inwardly rotating moments. In the sagittal dimension, the Distal Jet appliance allows almost translatory molar distalization. Accordingly, applying uprighting activation is not necessary for treatment. Because of the application of the force palatal to the center of resistance of the molars, the teeth experience undesired mesial-palatal and distal-facial rotation. CONCLUSIONS: The Distal Jet appliance allows almost translatory distal molar movement, and uprighting activation is not necessary for treatment. The force applied palatal to the center of resistance of the molars produces an undesired mesial-palatal and distal-facial rotation. Regular intraoral coil spring reactivation is needed.

Biomechanics of a modified Pendulum appliance--theoretical considerations and in vitro analysis of the force systems.

The aim of this study was to analyse the acting forces and moments induced by a special orthodontic appliance, the Pendulum K, for molar distalization in the transverse and sagittal planes. The purpose-designed test set-up (artificial maxilla with anchorage unit and two electrothermodynamic molars, an electronic measuring unit, a unit with force-moment sensor, an analogue/digital converter, and a data read-out unit) allowed simulation of in vivo conditions on the one hand and precise determination of the force systems on the other. The appliances investigated were three specimens of the Pendulum K. In vitro measurement of the resulting force systems revealed that the forces and moments in the transverse and sagittal planes remained almost constant over a 3 mm measuring increment when the distal screw was continuously activated (10 activations/mm). Without reactivation of the incorporated distal screw, however, a marked decline in the force systems was recorded. The Pendulum K allows translatory distalization of the upper molars and thus dental arch expansion, dispensing with the need for permanent teeth to be extracted, subject to a corresponding indication. This is achieved by continuous adjustment of an incorporated distal screw and by specific pre-activations of the Pendulum springs.

Distalamiento molar bilateral en el maxilar superior sin colaboración del paciente antes de la realización de la cirugía ortognática correctora; caso clínico que comprende su terapéutica la utilización del Quad Pendulum / Bilateral molar distalization in the superior maxilla without patient collaboration before the orthognathic surgey

La fase de nivelado prequirúrgica puede necesitar el distalamiento progresivo de los primeros y segundos molares. Si el mismo es realizado con aparatología que no requiera la colaboración del paciente y con anclaje dental exclusivamente, los molares deben ser distalados consecutivamente, para minimizar la pérdida de anclaje. El quad pendulum, péndulo modificado especialmente para poder tratar pacientes adultos, permite la distalación molar mediante el uso de cuatro resortes, cada uno de los cuales puede ser activado separadamente. Este péndulo modificaco puede ser anclado en un implante intraóseo

Distalamiento molar bilateral en el maxilar superior sin colaboración del paciente antes de la realización de la cirugía ortognática correctora; caso clínico que comprende su terapéutica la utilización del Quad Pendulum / Bilateral molar distalization in the superior maxilla without patient collaboration before the orthognathic surgey

La fase de nivelado prequirúrgica puede necesitar el distalamiento progresivo de los primeros y segundos molares. Si el mismo es realizado con aparatología que no requiera la colaboración del paciente y con anclaje dental exclusivamente, los molares deben ser distalados consecutivamente, para minimizar la pérdida de anclaje. El quad pendulum, péndulo modificado especialmente para poder tratar pacientes adultos, permite la distalación molar mediante el uso de cuatro resortes, cada uno de los cuales puede ser activado separadamente. Este péndulo modificaco puede ser anclado en un implante intraóseo(AU)

Molar distalization with pendulum appliances in the mixed dentition: effects on the position of unerupted canines and premolars.

INTRODUCTION: The pendulum appliance allows for rapid molar distalization without the need for patient compliance. Its efficiency has been confirmed in a number of clinical studies. However, the potential interactions and positional changes between the deciduous molars used for dental anchorage and the erupted and unerupted permanent teeth have yet to be clarified when this appliance is used for molar distalization in the mixed dentition. METHODS: Twenty-nine patients in the mixed dentition each received a modified pendulum appliance with a distal screw and a preactivated pendulum spring for bilateral distalization of the maxillary molars. The patients were divided into 4 groups based on dentition stages: patient group 1 (PG 1, n = 10) was in the early mixed dentition; patients had resorption of the distal root areas of the deciduous molars being used for dental anchorage, and the unerupted premolars were located at the distal margin of the deciduous molar root region. Based on radiographs taken before placement of the pendulum appliance, patient group 2 (PG 2, n = 10) was diagnosed as having a central location of the unerupted premolars. In the third group (PG 3, n = 4), the first premolars were already erupted and could be integrated into the dental anchorage, but the canines were not yet erupted. In the fourth group (PG 4, n = 5), the first premolars and both canines were fully erupted. RESULTS: Statistical analysis of the measured results showed significant differences in the side effects between PG 1 and PG 2. In patients being treated with pendulum appliances, the anchorage quality of the deciduous molars that were already partially resorbed in the distal root area was comparatively reduced. Consequently, the mesial drift of the deciduous molars and incisors was increased, without impairing the extent and quality of the molar distalization. Anchorage loss in the supporting area had no direct impact on the sagittal position of the unerupted premolars in the early mixed dentition. CONCLUSIONS: If permanent teeth have already started to erupt in the supporting area, additional space restrictions should be avoided in patients with critical topography, especially if there is little space for the unerupted canines. At this stage of the mixed dentition, premolar extraction or augmentation of the supporting area with extraoral headgear offers a therapeutic alternative to intraoral distalization appliances with exclusively dental anchorage.

Molar distalization with a modified pendulum appliance--in vitro analysis of the force systems and in vivo study in children and adolescents.

The standard pendulum appliance was modified by integrating a distal screw into its base and by special preactivation of the pendulum springs. The suitability of this Pendulum K for the translatory distalization of maxillary molars was investigated in an in vitro analysis and in an in vivo study in children and adolescents. The in vitro measurement of the resulting force systems revealed that all forces and moments remained virtually constant over a three-mm simulated distalization increment. The transverse force, Fx, increased from two to 11 cN and the weakly intrusively acting force, Fy, from six to eight cN, but these increases were not statistically significant. The distalization force, Fz, initially 201 cN, was still 199 cN after a three-mm distalization increment. The mesially acting moment, My, rose from 1654 to 1834 cN mm, whereas the palatally acting moment, Mz, declined slightly from 229 to 164 cN mm. The slight, consistent distoinclinatory moment, Mx, initially 306 cN mm, was 310 cN mm after three mm. In parallel, the in vivo study with its collective of 66 patients confirmed that the Pendulum K allows a virtually translatory molar distalization with slight tippings of 4.75 degrees to the palatal plane and 4.25 degrees to the anterior basal plane. Palatal movements of the first molars were avoided. The proportion of molar distalization in the total movement was 73.53%.

Anchorage quality of deciduous molars versus premolars for molar distalization with a pendulum appliance.

PURPOSE: The aim of this study was to assess dental anchorage qualities when the pendulum appliance is used for distal molar movement. MATERIAL: Thirty adolescents in various dentition stages received a modified pendulum appliance with a distal screw and a specially preactivated pendulum spring for bilateral molar distalization in the maxilla. The subjects were subcategorized into 3 groups of 10 according to the dental anchorage used: deciduous molars, premolars and deciduous molars, or only premolars. Dentoalveolar effects and side effects in the anchorage unit and in the molar area were determined by cephalometric analysis. RESULTS: Statistical analysis of the measurements showed significant differences between groups in the extent of molar distalization and the resulting incisor protrusion. Distal tipping of the 6-year molars was significantly less severe (2.3 degrees +/- 1.58 degrees to the palatal plane and 2.55 degrees +/- 1.52 degrees to the anterior cranial base) in patients with premolar anchorage than in those with deciduous molar anchorage (6.15 degrees +/- 3.42 degrees and 6.35 degrees +/- 3.46 degrees ). Incisor protrusion was significantly more pronounced in patients with deciduous molar anchorage (2.75 +/- 1.4 mm) than in the other 2 groups (1.65 +/- 0.82 mm, mixed deciduous molar and premolar anchorage, and 1.75 +/- 0.75 mm, premolar anchorage). Additionally, incisor protrusion was translatory compared with controlled tipping in subjects with deciduous molar anchorage or premolar and deciduous molar anchorage. CONCLUSIONS: Deciduous molars and premolars can be used for anchorage for molar distalization with a pendulum appliance; however, anchorage with premolars only results in the least pronounced dentoalveolar side effects. The anchorage quality of deciduous molar and mixed deciduous molar/premolar anchorage is limited.

Efficiency of a pendulum appliance for molar distalization related to second and third molar eruption stage.

A modified pendulum appliance, including a distal screw and special preactivated pendulum springs (built-in straightening activation and toe-in bending), was used for bilateral maxillary molar distalization in 36 adolescent patients in various stages of the molar dentition. The patients were divided into 3 groups (PG 1-3) according to the stage of eruption of their second and third molars. In PG 1 (18 patients), eruption of the second molars had either not yet taken place or was not complete. In PG 2 (15 patients), the second molars had already developed as far as the occlusal plane, with the third molars at the budding stage. In PG 3 (3 patients), germectomy of the wisdom teeth had been carried out, and the first and second molars on both sides had completely erupted. Analysis of cephalograms to identify any changes in the sagittal plane showed that, in the direction of distalization, a tooth bud acts on the mesial neighboring tooth like a fulcrum, and that tipping of the first molars in patients in whom the second molar was still at the budding stage was thus greater. In patients whose second molars had erupted completely, the degree of tipping was greater again when a third molar bud was located in the direction of movement. After previously completed germectomy of the wisdom teeth, almost exclusively bodily distalization of both molars is possible, even without bands being applied to the second molars. However, if the first and second molars are distalized simultaneously with a pendulum appliance, the duration of therapy will be longer, greater forces will have to be applied, and more anchorage will be lost. Statistical analysis of the results of dental-angular measurements showed significant differences in the degree of molar tipping and reciprocal incisor protrusion. The degree of distal tipping of first molars was less in patients with erupted second molars (PG 2 and PG 3) than in those whose second molars were not yet erupted (PG 1). For instance, the measured angles were 0.9 degrees +/- 3.43 degrees (to the palatal plane) and 0.8 degrees +/- 3.4 degrees (to the anterior cranium floor) in PG 2, and -0.33 degrees +/- 0.58 degrees and 0.67 degrees +/- 2.08 degrees, respectively, in PG 3, contrasting with respective values of 5.89 degrees +/- 3.74 degrees and 5.36 degrees +/- 3.49 degrees in PG 1. Tipping of erupted second molars was much more marked in PG 2 (7.92 degrees +/- 5.83 degrees to the palatal plane and 7.55 degrees +/- 5.28 degrees to the anterior cranium floor), but much less pronounced in PG 3 (2 degrees +/- 1.73 degrees to the palatal plane and 2 degrees +/- 2 degrees to the anterior cranium floor) than the corresponding movement of the second budding-stage molars in PG 1 (4.06 degrees +/- 2.15 degrees and 3.97 degrees +/- 2.27 degrees, respectively). The degree of incisor protrusion occurring reciprocally with molar distalization was much less in these patients (measured angles of 3.28 degrees +/- 1.97 degrees and 2.89 degrees +/- 2.17 degrees to the palatal plane and anterior cranium floor, respectively) than in the patients presenting different stages of the dentition (angles of 5.5 degrees +/- 3.33 degrees and 6.03 degrees +/- 4.29 degrees, respectively, in PG 2, and angles of 5.5 degrees +/- 3.28 degrees and 6.67 degrees +/- 3.09 degrees, respectively, in PG 3). Moreover, measurement of dental casts in the horizontal plane showed not only the targeted mesiobuccal rotation of both maxillary molars, but also a vestibular drift of the unbanded second molars.

Orthodontic fine adjustment after vertical callus distraction of an ankylosed incisor using the floating bone concept.

The outcome of vertical callus distraction of a segment of tooth-supporting alveolar process might be functionally and esthetically unsatisfactory because of the unidirectional impact of intraoral distraction devices. In this case report, we describe how, with a shortened consolidation phase and application of the floating bone effect, the tooth-supporting osteotomy segment can be successfully aligned 3 dimensionally. We applied orthodontic force systems that went beyond the unidirectional vector preset by the mechanical properties of the distraction device.