Kurt Faltin

Long-term Effectiveness and Treatment Timing for Bionator Therapy

The aim of the present investigation was to provide information about the long-term effects and optimal timing for class-II treatment with the Bionator appliance. Lateral cephalograms of 23 class-II patients treated with the Bionator were analyzed at three time periods: T1, start of treatment; T2, end of Bionator therapy; and T3, long-term observation (after completion of growth). T3 includes a phase with fixed appliances. The treated sample was divided into two groups according to their skeletal maturity as evaluated by the cervical vertebral maturation (CVM) method. The early-treated group (13 subjects) initiated treatment before the peak in mandibular growth, which occurred after completion of Bionator therapy. The late-treated group (10 subjects) received Bionator treatment during the peak. The T1-T2, T2-T3, and T1-T3 changes in the treated groups were compared with changes in control groups of untreated class-II subjects by nonparametric statistics (P < .05). The findings of the present study on Bionator therapy followed by fixed appliances indicate that this treatment protocol is more effective and stable when it is performed during the pubertal growth spurt. Optimal timing to start treatment with the Bionator is when a concavity appears at the lower borders of the second and the third cervical vertebrae (CVMS II). In the long-term, the amount of significant supplementary elongation of the mandible in subjects treated during the pubertal peak is 5.1 mm more than in the controls, and it is associated with a backward direction of condylar growth. Significant increments in mandibular ramus height also were recorded.

Root Resorptions in Upper First Premolars after Application of Continuous Torque Moment Intra-Individual Study

AbstractMaterial and Method: With the purpose of investigating the occurrence, localization and extension of possible root resorptions after fixed appliance treatment with a continuous torque force, 28 upper first premolars orthodontically indicated for extraction from 14 patients were analyzed by scanning electron microscopy. Tooth movement was carried out with continuous moments of different magnitudes (300 cNmm, and 600 cNmm), using a biomechanical model with superelastic wires (stainless steel-NiTi-SE), which was specially designed and individually calibrated. The teeth were divided into one control group with four premolars (non-moved) from two patients, and two experimental groups (300 cNmm and 600 cNmm respectively) with six patients each. Each group was distributed intra-individually as follows: the right first premolar of six patients was extracted after 1 week of movement, the left first premolars were removed after 2, 3 and 4 weeks. After extraction, teeth were fixed, treated with 2% sodium hypochlorite solution for 6 hours in order to remove the organic tissue components, dehydrated, and metalcoated in a Balzers SCD 050 apparatus. Results: The analysis in a scanning electron microscope (Jeol 6100, at 10–15 kV) revealed many resorption lacunae in the root surface, mainly on the lingual side in the apical third of the roots. Resorption processes were also observed on the buccal root surface in the cervical third. All experimental teeth showed resorption areas. Teeth which had been moved for a longer time period and with a higher magnitude of applied moments showed a higher degree of root resorption in width as well as in depth. Higher magnitude of moments produced exposure of root dentine, evidencing pronounced root resorption.ZusammenfassungMaterial und Methode: 28 erste obere Prämolaren von 14 Patienten, die aus kieferorthopädischen Gründen zur Extraktion vorgesehen waren, wurden rasterelektronenmikroskopisch untersucht, um die Präsenz, die Lage und die Ausdehnung möglicher Wurzelresorptionen während kontinuierlichem Torque zu untersuchen. Das kontinuierliche Moment unterschiedlicher Größe (300 cNmm und 600 cNmm) wurde durchgeführt mit Hilfe einer biomechanischen Apparatur mit superelastischen Drähten (NiTi-SE-Stahl), die individuell entwickelt und kalibriert war. Es erfolgte eine Einteilung der Zähne in eine Kontrollgruppe mit vier Prämolaren (nicht bewegt) von zwei Patienten und zwei experimentelle Gruppen (300 cNmm und 600 cNmm) von jeweils sechs Patienten. Jede Gruppe wurde intraindividuell wie folgt eingeteilt: Die ersten rechten Prämolaren von sechs Patienten wurden, nachdem sie 1 Woche bewegt wurden, extrahiert, die ersten linken Prämolaren wurde jeweils nach 2, 3 und 4 Wochen extrahiert. Nach der Extraktion wurden die Zähne für 6 Stunden in 2% Natriumhypochloritlösung gelegt, um die organischen Teile zu entfernen. Es erfolgte die Trocknung und Metallbeschichtung im Balzers-SCD-050-Gerät. Ergebnisse: Die Untersuchung mit dem Rasterelektronenmikroskop zeigte viele Konkavitäten (Resortionslakunen), die sich hauptsächlich auf der lingualen Fläche des apikalen Wurzeldrittels befanden. Diese fanden sich auch auf der bukkalen Fläche des zervikalen Drittels. Alle bewegten Zähne wiesen resorptive Bereiche auf. Zähne, die über einen längeren Zeitraum mit größeren Momenten bewegt worden waren, zeigten stärkere Resorptionen in Breite und Tiefe. Größere Momente erzeugten eine Freilegung des Dentins und ausgeprägte Wurzelresorptionen.

Long-term skeletal and dental effects and treatment timing for functional appliances in Class II malocclusion

OBJECTIVE To analyze the long-term skeletal and dentoalveolar effects and to evaluate treatment timing of Class II treatment with functional appliances followed by fixed appliances. MATERIALS AND METHODS A group of 40 patients (22 females and 18 males) with Class II malocclusion consecutively treated either with a Bionator or an Activator followed by fixed appliances was compared with a control group of 20 subjects (9 females and 11 males) with untreated Class II malocclusion. Lateral cephalograms were available at the start of treatment (mean age 10 years), end of treatment with functional appliances (mean age 12 years), and long-term observation (mean age 18.6 years). The treated sample also was divided into two groups according to skeletal maturity. The early-treatment group was composed of 20 subjects (12 females and 8 males) treated before puberty, while the late-treatment group included 20 subjects (10 females and 10 males) treated at puberty. Statistical comparisons were performed with analysis of variance followed by Tukeys post hoc tests. RESULTS Significant long-term mandibular changes (Co-Gn) in the treated group (3.6 mm over the controls) were associated with improvements in the skeletal sagittal intermaxillary relationship, overjet, and molar relationship (∼3.0-3.5 mm). Treatment during the pubertal peak was able to produce significantly greater increases in total mandibular length (4.3 mm) and mandibular ramus height (3.1 mm) associated with a significant advancement of the bony chin (3.9 mm) when compared with treatment before puberty. CONCLUSION Treatment of Class II malocclusion with functional appliances appears to be more effective at puberty.

Long-term dentoskeletal effects and facial profile changes induced by bionator therapy.

OBJECTIVE To evaluate the long-term skeletal and soft tissue changes induced by the bionator in Class II subjects. MATERIALS AND METHODS The treatment sample consisted of 20 Class II patients (6 males and 14 females) treated consecutively with the bionator. The sample was evaluated at T1, start of treatment; T2, end of bionator therapy; and T3, long-term observation (including fixed appliances). Mean age at the start of treatment was 10 years 2 months (T1); at posttreatment, 12 years 4 months (T2); and at long-term follow-up, 18 years 11 months (CS 6). The control group consisted of 20 subjects (8 males and 12 females) with untreated Class II malocclusions. Lateral cephalograms were analyzed at the three time points for all groups. Students t-tests were used for comparisons of starting forms, and of the T1-T2 and T1-T3 changes between groups. RESULTS The bionator group showed significant, favorable T1-T2 changes both at the skeletal and dentoalveolar levels. The vertical dimension was increased. Significant modifications were assessed for the soft tissues as well. The treated group showed a final improvement in soft tissue pogonion of about 2.5 mm. Significant mandibular changes were noted in the treated group, with a net average 3.3 mm long-term increase in mandibular length compared with untreated Class II controls. CONCLUSIONS This study suggests that bionator treatment of Class II malocclusion maintains favorable results over the long-term with a combination of skeletal, dentoalveolar, and soft tissue changes.

Periodontal Ligament Hydrostatic Pressure with Areas of Root Resorption after Application of a Continuous Torque Moment

OBJECTIVE To evaluate the risk of root resorption, individual finite element models (FEMs) of extracted human maxillary first premolars were created, and the distribution of the hydrostatic pressure in the periodontal ligament (PDL) of these models was simulated. MATERIALS AND METHODS A continuous lingual torque of 3 Nmm and 6 Nmm respectively was applied in vivo to the aforementioned teeth. After extraction, FEMs of these double-rooted teeth were created based on high-resolution microcomputed tomographics (micro CT, voxel size: 35 microns). This high volumetric resolution made the recognition of very small resorption lacunae possible. Scanning electron micrographs of the root surfaces were created as well. This enabled the investigation of advantages and disadvantages of the different imaging techniques from the viewpoint of the examination of root resorption. Using the FEMs, the same loading conditions as applied in vivo were simulated. RESULTS The results of clinical examination and simulations were compared using the identical roots of the teeth. The regions that showed increased hydrostatic pressure (>0.0047 MPa) correlated well with the locations of root resorption for each tooth. Increased torque resulted in increased high-pressure areas and increased magnitudes of hydrostatic pressure, correlating with the experiments. CONCLUSION If hydrostatic pressure exceeds typical human capillary blood pressure in the PDL, the risk of root resorption increases.

Root resorptions in upper first premolars after application of continuous intrusive forces

A scanning electron microscopy study of possible root resorptions and their localization after application of continuous forces of different magnitudes was conducted. Twelve upper first premolars, indicated for extraction, were previously intruded with constant forces. The teeth were divided into 3 groups: 1. non-moved control teeth, 2. continuous force application of 50 cN for 4 weeks, 3. continuous force application of 100 cN for 4 weeks. Specially designed NiTi-SE-stainless steel springs were utilized to exert the actual forces. After experimental tooth movement, the extracted teeth were dehydrated, metal-coated and examined by scanning electron microscopy. The intruded teeth showed resorptive areas consisting of lacunae (concavities) in the mineralized root surface. The teeth moved with 50 cN showed in the apical third several, in the medial third few, and in the cervical third no resorptive areas. In the case of the teeth moved with 100 cN, we observed resorptive areas in most of the apical third—including the apex contour—, several in the medial third, and none in the cervical third. In the control group no resorptions were observed. Thus, our results suggest that intrusion of human teeth with continuous forces induces root resorption, depending on the magnitude of force applied.ZusammenfassungEine histologische Studie der möglichen Wurzelresorptionen und ihre Lokalisation bei der Anwendung kontinuierlicher Kräfte unterschiedlicher Größe wurde durchgeführt. Zwölf erste obere Prämolaren, die im Rahmen einer Extraktionstherapie entfernt werden sollten, wurden vorher mit konstanten Kräften intrudiert. Es erfolgte eine Einteilung in drei Gruppen: 1. nichtbewegte Kontrollzähne, 2. kontinuierliche Kraftapplikation mit 50 cN für vier Wochen, 3. kontinuierliche Kraftapplikation von 100 cN für vier Wochen. Zur Anwendung kamen speziell gefertigte NiTi-SE-Stahl-Federn, die die jeweiligen Kräfte ausübten. Die entfernten Zähne wurden nach entsprechender Aufarbeitung metallbeschichtet und in einem Rasterelektronenmikroskop untersucht. Die resorptiven Bereiche zeigten sich in Form von Lakunen (Konkavitäten) im Bereich der mineralisierten Wurzeloberfläche der intrudierten Zähne. Die mit 50 cN bewegten Zähne zeigten im apikalen Drittel mehrere, im medialen Drittel selten und im zervikalen Drittel keine resorptiven Bereiche. Bei den mit 100 cN bewegten Zähnen konnten resorptive Bereiche im überwiegenden Teil des apikalen Drittels-einschließlich der Wurzelspitzenkontur-, im mittleren Drittel nur gelegentlich und im zervikalen Drittel keine resorptiven Bereiche beobachtet werden. Bei der Kontrollgruppe traten keine Resorptionen auf. Eine Intrusion menschlicher Zähne mit kontinuierlichen Kräften verursacht Wurzelresorptionen, die von der angewandten Kraftgröße abhängig sind.

Root resorption on torqued human premolars shown by tartrate-resistant acid phosphatase histochemistry and transmission electron microscopy.

OBJECTIVE To identify clastic cells on the root surfaces of torqued human premolars. MATERIALS AND METHODS A continuous force of 600 cNmm was applied to upper first premolars in patients 13-16 years of age by using a precise biomechanical model with superelastic wires (NiTi-SE). The 28 teeth in 14 patients were divided into five groups (control [nonmoved], and moved for either 1, 2, 3, or 4 weeks) and processed for tartrate-resistant acid phosphatase (TRAP) histochemistry and transmission electron microscopy. RESULTS Mononuclear TRAP-positive cells appeared at 2 weeks, where as large multinucleated TRAP-positive cells were numerous at 3 and 4 weeks. Ultrastructural examination revealed many clastic cells in contact with resorption lacunae. In addition, some cementoblast-like cells appeared secreting new cementum over previously resorbed lacunae. CONCLUSIONS In general, resorption lacunae and the number of clastic cells, which increased with the duration of the applied force, were found on the cementum surface at the pressure areas. Some signs of cementum repair were also noticed, even with the maintenance of the level of the force.

Quantification of cranial base growth during pubertal growth.

Objective To quantify longitudinal cranial base growth from prepubertal through postpubertal stages of development, as defined by biological indicators of individual skeletal maturity (cervical vertebral maturation – CVM) method and to determine if there is sexual dimorphism resulting from cranial base growth. Design A longitudinal cephalometric study. Setting The Dental School of Paulista University, Brazil. Participants 36 subjects (21 females, 15 males) who were part of a longitudinal growth study and exhibited normal facial and normal vertical growth patterns. Methods Growth maturation of cervical vertebrae stages was assessed by two examiners independently. Cranial base measurements were carried out by one individual and repeated after one month. The growth increments over time were assessed with the one-way repeated-measures analysis of variance and post hoc Tukey multiple comparisions. Results There were no significant gender differences. There was a significant increase in all cephalometric measures between the different time points. Ba–Na showed the greatest amount of growth (mean change=2.8 mm). From T2–T3, the greatest amount of growth was found for Se–Na (mean change=3.4 mm) and the lowest for CC–Na (mean change=1.4 mm). Comparing overall changes (T1–T3) all the measurements showed statistically significantly increases (P<0.05). For all comparisons of between-stage changes the cranial base grew more than 2.0 mm during the pubertal growth. Conclusions Linear variables of cranial base showed significant growth during pubertal stages (pre-peak, peak and post-peak). No significant differences.

Morphometric analysis of treatment effects of the Balters bionator in growing Class II patients

OBJECTIVE To investigate the effects of the standard (Class II) Balters bionator in growing patients with Class II malocclusion with mandibular retrusion by using morphometrics (thin-plate spline [TPS] analysis). MATERIALS AND METHODS Thirty-one Class II patients (17 male and 14 female) were treated with the Balters bionator (bionator group). Mean age at the start of treatment (T0) was 10.3 years, while it was 13 years at the end of treatment (T1). Mean treatment time was 2 years and 2 months. The control group consisted of 22 subjects (14 male and 8 female) with untreated Class II malocclusion. Mean age at T0 was 10.2 years, while it was 12.2 years at T1. The observation period lasted 2 years on average. TPS analysis evaluated statistical (permutation tests) differences in the craniofacial shape and size between the bionator and control groups. RESULTS Through TPS analysis (deformation grids) the bionator group showed significant shape changes in the mandible that could be described as a mandibular forward and downward displacement. The control group showed no statistically significant differences in the correction of Class II malocclusion. CONCLUSIONS Bionator appliance is able to induce significant mandibular shape changes that lead to the correction of Class II dentoskeletal disharmony.

Morphometric analysis of long-term dentoskeletal effects induced by treatment with Balters bionator

OBJECTIVE To evaluate the long-term effects of the standard (Class II) Balters bionator in growing patients with Class II malocclusion with mandibular retrusion by using morphometrics (thin-plate spline [TPS] analysis). MATERIALS AND METHODS Twenty-three Class II patients (8 male, 15 female) were treated consecutively with the Balters bionator (bionator group). The sample was evaluated at T0, start of treatment; T1, end of bionator therapy; and T2, long-term observation (including fixed appliances). Mean age at the start of treatment was 10 years 2 months (T0); at posttreatment, 12 years 3 months (T1); and at long-term follow-up, 18 years 2 months (T2). The control group consisted of 22 subjects (11 male, 11 female) with untreated Class II malocclusion. Lateral cephalograms were analyzed at the three time points for all groups. TPS analysis evaluated statistical differences (permutation tests) in the craniofacial shape and size between the bionator and control groups. RESULTS TPS analysis showed that treatment with the bionator is able to produce favorable mandibular shape changes (forward and downward displacement) that contribute significantly to the correction of the Class II dentoskeletal imbalance. These results are maintained at a long-term observation after completion of growth. The control group showed no statistically significant differences in the correction of Class II malocclusion. CONCLUSIONS This study suggests that bionator treatment of Class II malocclusion produces favorable results over the long term with a combination of skeletal and dentoalveolar shape changes.