Alexander Pauls

Therapeutic Accuracy of Individualized Brackets in Lingual Orthodontics

AbstractObjective:Verification of the therapeutic accuracy of the Incognito ® bracket system.Material and Methods:The therapeutic set-up casts and final treatment casts were digitalized using a 3D scanner, and the scans were subsequently superimposed. The deviations in rotation and translation of each tooth in the three spatial dimensions were calculated.Results:The front teeth showed deviations in rotations of less than 4.6° and in translations under 0.5 mm. In addition, influences such as upper or lower jaw, growth, type of tooth, anterior tooth position, bracket generation, 3D scanner hardware and finishing archwires were analyzed.Conclusion:The clinical impression was confirmed by the measurements taken in this study. The final results following lingual orthodontic treatment using individualized brackets correlate satisfactorily with the therapeutic set-ups.ZusammenfassungZiel:Verifizierung der Behandlungsgenauigkeit des Incognito®- Bracketsystems.Material und Methodik:Die therapeutischen Set-up- und Abschlussmodelle wurden mittels 3D-Scanner digitalisiert, virtuell überlagert und von jedem einzelnen Zahn die Abweichungen der Rotationen und Translationen in den drei Raumdimensionen berechnet.Ergebnisse:Die Frontzähne zeigten Abweichungen der Rotationen von weniger als 4,6° und der Translationen von unter 0,5 mm. Außerdem wurden besondere Einflüsse wie Kiefer, Wachstum, Zahn-Typ, Frontzahnstellung, Bracketgeneration, Hardware des 3D-Scanners und verwendete Finishing-Bögen analysiert.Schlussfolgerung:Der klinisch gewonnene Eindruck konnte durch die Messergebnisse der Studie bestätigt werden. Eine zufriedenstellende Übereinstimmung des Endergebnisses mit dem therapeutischen Set-up ist in der Lingualtechnik mittels individualisierter Brackets realisierbar.

Measurement of mini-implant stability using resonance frequency analysis.

OBJECTIVE To investigate whether resonance frequency analysis (RFA) is suitable to measure orthodontic mini-implant stability. Implant size significantly affects the level of resonance frequency. Regarding the operating mode of RFA, it has to be proven whether the resonance frequency of mini-implants in bone fits the range of frequency emitted by the Osstell ISQ device. MATERIAL AND METHODS For this purpose the SmartPegs in the Osstell ISQ device were modified to fit with the inner screw thread of orthodontic mini-implants, and 110 mini-implants were inserted into porcine pelvic bone. RFA was performed parallel and perpendicular to the run of superficial bone fibers. A suitability test, Periotest, was also performed in the same directions. Compacta thickness was measured using cone-beam computed tomography. Correlation tests and linear regression analysis were carried out between the three methods. RESULTS The RFA showed a mean Implant Stability Quotient value of 36.36 ± 2.67, and the Periotest mean value was -2.10 ± 1.17. The differences between the two directions of measurement were statistically significant (P > .001) for RFA and the Periotest. There was a high correlation between RFA and the Periotest (r  =  -0.90) and between RFA and compacta thickness (r  =  0.71). The comparison between the Periotest and compacta thickness showed a correlation coefficient of r  =  -0.64. CONCLUSION The present results suggest that RFA is feasible as a measurement method for orthodontic mini-implant stability. As a consequence, it could be used for clinical evaluation of current stability and allow stability-related loading of mini-implants to reduce the failure rate.

Maxillary protraction using a hybrid hyrax-facemask combination

BackgroundThe aim of this in study was the evaluation of treatment outcomes after using a hybrid hyrax-facemask combination in growing class III patients.MethodsTreatment of 16 children (mean age 9.5 ± 1.3 years) was investigated clinically and by means of pre- and post-treatment cephalograms. Changes in sagittal and vertical, and dental and skeletal values were evaluated and tested for statistically significant differences.ResultsAll mini-implants remained stable during treatment. Mean treatment duration was 5.8 ± 1.7 months. There was a significant improvement in skeletal sagittal values: SNA, +2.0°; SNB, -1.2°; ANB, +3.2°; WITS appraisal, +4.1 mm and overjet, +2.7 mm. No significant changes were found concerning vertical skeletal relationships and upper incisor inclination. In relation to A point, the upper first molars moved mesially about 0.4 mm (P = 0.134).ConclusionsThe hybrid hyrax-facemask combination seems to be effective for orthopaedic treatment in growing class III patients. Unwanted maxillary dental movements can be avoided due to stable skeletal anchorage.

Mini-implant stability at the initial healing period: A clinical pilot study

OBJECTIVE To evaluate the changes of mini-implant stability over the initial healing period in humans. MATERIAL AND METHODS A sample of 19 consecutively treated patients (mean age 15.5 ± 7.3 years) was examined. In each patient, a mini-implant of a size of 2 × 9 mm was inserted into the anterior palate. Implant stability was assessed using resonance frequency analysis (RFA) immediately after insertion (T0), 2 weeks later (T1), 4 weeks later (T2), and 6 weeks later (T3). Insertion depth (ID) and the maximum insertion torque (IT) were measured. Data were tested for correlations between RFA, ID, and IT. All RFA values were tested for statistically significant differences between the different times. RESULTS The mean ID was 7.5 ± 0.6 mm, and the mean IT was 16.8 ± 0.6 Ncm. A correlation was found between RFA and ID (r = .726, P < .0001), whereas no correlations between RFA and IT or between IT and ID were observed. From T0 to T1, the stability (36.1 ± 6.1 implant stability quotient [ISQ]) decreased nonsignificantly by 4.9 ± 6.1 ISQ values (P > .05). Between T1 and T2, the stability decreased highly significantly (P < .001) by 7.9 ± 5.9 ISQ values. From T2 on, RFA remained nearly unchanged (-1.7 ± 3.5 ISQ; P > .05). CONCLUSIONS Mini-implant stability is subject to changes during the healing process. During weeks 3 and 4, a significant decrease of the stability was observed. After 4 weeks, the stability did not change significantly.

Effects of wear time recording on the patient's compliance.

OBJECTIVE To assess the effect of wear-time recording on subjective and objective wear time. MATERIALS AND METHODS This study retrospectively examined a group of 18 patients and a control group of 14 patients at four appointments over 168 days. The patients were treated with removable appliances with embedded TheraMon-microsensors to be worn for 15 hours per day. The study group was not told about the microsensor until the first appointment after fitting of the appliance. At each appointment patients were asked about their subjective wear time and afterward were told about the objective wear time. The existence of the microsensor was revealed to the control group when the appliance was fitted. Objective wear time was also announced at every appointment. RESULTS Mean wear times did not significantly differ between groups at any appointment or regarding overall wear time. Highly significant differences between subjective and objective wear time were found when patients did not know that their wear time had been monitored. CONCLUSION Mean wear times assessed in this study concur with data of previous studies. Patients tend to overestimate their wear times but become more realistic once they know wear time is being monitored. Objective measurement of wear time allows a more realistic view of compliance by patient and orthodontist. Knowing that wear time is recorded does not necessarily increase the amount of time removable appliances are worn by the patient.

Stability of paramedian inserted palatal mini-implants at the initial healing period: a controlled clinical study

OBJECTIVES To assess the stability development of paramedian in comparison with midpalatal inserted mini-implants. MATERIAL AND METHODS The test group consisted of 21 consecutively treated patients (13.7 ± 4.6 years). In each patient, a mini-implant was inserted paramedian in the anterior palate. Measurement of the insertion depth (ID), the maximum insertion torque (IT), and resonance frequency analysis (RFA) was performed at T0. RFA was repeated after 2 weeks (T1), 4 weeks (T2), and 6 weeks (T3). Correlations between measuring methods were calculated. RFA values at different times were tested for statistical differences. Data were compared with a group of patients who received median mini-implants of the same size. RESULTS Initial stability was 14.06 ± 4.35 Ncm (IT) and 26.60 ± 5.28 ISQ (RFA) with an ID of 7.02 ± 1.04 mm. RFA and IT (r = 0.49, P = 0.023) showed a moderate significant correlation. Stability remained relatively constant, showing no significant differences between measurement times. Overall, RFA values decreased non-significantly by 2.25 ± 6.85 ISQ to a level of 24.35 ± 5.39 after 6 weeks. Comparing development of stability over time, it was found that significant differences were present at T0 and T1 (T0: -9.54 ISQ, P < 0.0001; T1: -3.69, P = 0.041). CONCLUSIONS Paramedian inserted mini-implants provided sufficient stability. Showing a lower primary stability, RFA values did not differ from the control group from week four on, as no significant decrease in stability occurred at the initial healing period.