Ludwig B

Survival of palatal miniscrews used for orthodontic appliance anchorage: A retrospective cohort study

INTRODUCTION The purpose of this study was to examine the overall success of miniscrews inserted in the paramedian palatal region for support of various appliances during orthodontic treatment. METHODS The patients received 1 or 2 miniscrews in the paramedian anterior palate of 8.0-mm length and 1.6-mm diameter placed during orthodontic treatment by the same experienced orthodontist. RESULTS In total, 196 patients (121 girls, 75 boys; median age, 11.7; interquartile range, 3.7) who received 384 miniscrews were evaluated. Two hundred four miniscrews were used with rapid palatal expansion appliances, 136 with appliances for distalization of posterior teeth, and 44 with other appliances, such as transpalatal arches for tooth stabilization. The overall survival of the miniscrews was excellent (97.9%) in the cases examined. Cox regression analysis showed no difference in the overall survival rates of miniscrews loaded with different appliances for sex (hazard ratio, 0.95; 95% confidence interval, 0.71-1.27; P = 0.73) after adjusting for appliance and age. CONCLUSIONS This study shows that miniscrews placed in the paramedian anterior palate for supporting various orthodontic appliances have excellent survival.

Objective assessment of patient compliance with removable orthodontic appliances: A cross-sectional cohort study

OBJECTIVE To assess objectively patient compliance with removable orthodontic appliances and the effect of possible influential factors. MATERIALS AND METHODS Wearing times of 45 White patients were recorded with the aid of the TheraMon microsensor. Patient compliance was assessed relative to wear prescription and other parameters, such as age and sex. RESULTS There was high individual variation in most measured variables and in all groups/subgroups. During a median observation period of 186 days (range, 55-318 days) the actual wear time was 9.0 h/d (range, 0.0-16.0 h/d) and did not differ between distinct prescriptions (P = .49). Eight patients wore their appliances less than 2 h/d, and six of them did not wear their appliances at all. Overall, the median wear per day relative to prescription was 62.5% (range, 0.0-89.3%) for the 14 h/d and 112.5% (range, 0.0-200.0%) for the 8 h/d prescription wear (P = .01) groups. There was a strong negative correlation of age (median: 12.5 years) with the daily percentage of actual wear time per day relative to wear prescription (14 h/d prescription: n = 21, rho = -0.61, P = .00; 8 h/d prescription: n = 24, rho = -0.73, P = .00), while sex did not exert a significant influence on compliance (P = .58). CONCLUSIONS Despite the fact that patients and parents were informed about wear time recording, compliance was insufficient with regard to functional treatment (14 h/d prescription), while it was sufficient for retention purposes (8 h/d prescription). Objective measures are necessary to assess compliance with removable orthodontic appliances since patient compliance is a highly variable issue.

Evaluation of 3-dimensional superimposition techniques on various skeletal structures of the head using surface models.

Objectives To test the applicability, accuracy, precision, and reproducibility of various 3D superimposition techniques for radiographic data, transformed to triangulated surface data. Methods Five superimposition techniques (3P: three-point registration; AC: anterior cranial base; AC + F: anterior cranial base + foramen magnum; BZ: both zygomatic arches; 1Z: one zygomatic arch) were tested using eight pairs of pre-existing CT data (pre- and post-treatment). These were obtained from non-growing orthodontic patients treated with rapid maxillary expansion. All datasets were superimposed by three operators independently, who repeated the whole procedure one month later. Accuracy was assessed by the distance (D) between superimposed datasets on three form-stable anatomical areas, located on the anterior cranial base and the foramen magnum. Precision and reproducibility were assessed using the distances between models at four specific landmarks. Non parametric multivariate models and Bland-Altman difference plots were used for analyses. Results There was no difference among operators or between time points on the accuracy of each superimposition technique (p>0.05). The AC + F technique was the most accurate (D<0.17 mm), as expected, followed by AC and BZ superimpositions that presented similar level of accuracy (D<0.5 mm). 3P and 1Z were the least accurate superimpositions (0.790.05), the detected structural changes differed significantly between different techniques (p<0.05). Bland-Altman difference plots showed that BZ superimposition was comparable to AC, though it presented slightly higher random error. Conclusions Superimposition of 3D datasets using surface models created from voxel data can provide accurate, precise, and reproducible results, offering also high efficiency and increased post-processing capabilities. In the present study population, the BZ superimposition was comparable to AC, with the added advantage of being applicable to scans with a smaller field of view.

Microelectronic wear-time documentation of removable orthodontic devices detects heterogeneous wear behavior and individualizes treatment planning.

INTRODUCTION The aim of this study was to investigate whether microelectronic wear-time documentation can contribute to individualized orthodontic management. METHODS The wear times and behaviors of 281 patients undergoing orthodontic treatment with removable appliances were quantified and analyzed using the TheraMon microelectronic system (Sales Agency Gschladt, Hargelsberg, Austria) over a 6-month treatment period. RESULTS The 281 study participants wore their removable appliances for a median of 9.0 hours per day, compared with the 12 to 15 hours per day prescribed. Wear behavior was variable and heterogeneous in patients with almost identical median wear times, with fluctuating and numerous zero wear-time periods observed. CONCLUSIONS Both the duration of daily wear time and the wear behavior need to be considered to individualize the prescription for wear time; this is made possible with microelectronic wear-time documentation. Individual prescription changes based on the wear-time documentation can be arranged with patients in a shared decision-making process to achieve effective and successful treatment progress.

Editor's Summary and Q&A: Five-year experience with orthodontic miniscrew implants: A retrospective investigation of factors influencing success rates

INTRODUCTION Anchorage control is important for efficient orthodontic treatment with fixed appliances. Successful osseointegration encouraged many orthodontists to use dental implants as stationary anchorage units for force application. However, their use has some drawbacks, which led to the development of miniscrew implants (MIs). Our aim was to investigate factors significantly contributing to the success rates of MIs in various orthodontic treatment procedures in white patients. METHODS In total, 350 self-tapping (187 Abso Anchor [Dentos, Daegu, South Korea] and 163 Ortho Easy Pin [Forestadent, Pforzheim, Germany]) MIs used to reinforce orthodontic anchorage and placed in 130 consecutively chosen patients were assessed retrospectively. Clinical variables possibly influencing the success rates of MIs were categorized into patient-related, implant-related, location-related, and orthodontic-related. Statistical evaluation included descriptive statistics and survival analysis. The survival curves of the MIs with respect to the various factors were estimated and plotted by using the Kaplan-Meier product-limit estimate. The MI survival distributions for each factor were compared with the log rank test for simple comparisons or the Cox regression for multiple variables. RESULTS The overall success rates of MIs that remained stable during a mean treatment time of 19.2 +/- 2.3 months was 93.43%; this was considerably higher than in previous reports. Only a few factors were found to be associated with statistically significant higher success rates of MIs, including deep bites, placement in the attached gingiva of the maxilla, and en-masse distalization of teeth. CONCLUSIONS The success rates of MIs in white patients were greater than the corresponding rates reported for Asian patients. Our results confirm the effectiveness of orthodontic MIs as temporary anchorage reinforcement devices and suggest various clinical factors as potential causes of failure.

Fully customized placement of orthodontic miniplates: a novel clinical technique

IntroductionThe initial stability and survival rate of orthodontic mini-implants are highly dependent on the amount of cortical bone at their insertion site. In areas with limited bone availability, mini-plates are preferred to provide effective skeletal anchorage. The purpose of this paper was to present a new clinical technique for the insertion of mini-plates.MethodsIn order to apply this new technique, a cone-beam image of the insertion area is required. A software (Galaxy Sirona, Bensheim, Germany) is used to construct a three-dimensional image of the scanned area and to virtually determine the exact location of the mini-plate as well as the position of the fixation screws. A stereolithographic model (STL) is then created by means of a three-dimensional scanner.Prior to its surgical insertion, the bone plate is adapted to the stereo-lithographic model. Finally, a custom transfer jig is fabricated in order to assist with accurate placement of the mini-plate intra-operatively.ResultsThe presented technique minimizes intra-operative decision making, because the final position of the bone plate is determined pre-surgically. This significantly reduces the duration of the surgical procedure and improves its outcome.ConclusionsA novel method for surgical placement of orthodontic mini-plates is presented. The technique facilitates accurate adaptation of mini-plates and insertion of retaining surgical screws; thereby enabling clinicians to more confidently increase the use of bone plates, especially in anatomical areas where the success of non-osseointegrated mini-screws is less favorable.

Treatment Results at 10, 15, and 18 Years of Age in Patients With Complete Bilateral Cleft Lip and Palate: An Intercenter Comparison

Objective The aim of this study was to investigate and compare the skeletal treatment outcome in patients aged 18 years with complete bilateral cleft lip and palate who received their complete treatment until early adulthood in two centers with different treatment protocols. Design Twenty-two patients (13 from center 1, nine from center 2) with complete primary bilateral cleft lip alveolus and palate were included. Lateral cephalograms were studied at the ages of 10 (T1), 15 (T2), and 18 (T3) years. Sagittal, vertical, and dental parameters were measured and compared. Statistics included tests for normal distribution, a three-way analysis of variance, and bilateral t tests for associated and nonassociated random samples with the significance level p < .05. Results Data from center 1 showed a significant decrease in ANB, WITs appraisal, and NL-NSL and an increase in Ui/NL. Data from center 2 showed a significant increase in SNB; a decrease in ANB, WITs appraisal, and ML-NSL; and an increase in Ui/NL. The intercenter comparison of means at the end of treatment (T3) revealed no significant differences for any parameter, despite few significant differences at T1 and T2. Conclusion The different treatment concepts did not yield significant differences in treatment outcome at early adulthood. All final skeletal parameters were comparable to those of patients without a cleft. These results indicate treatment execution may be more important than the treatment protocol.

Biocompatibility of gold and stainless steel chains used for forced eruption of impacted teeth – an in vitro investigation

OBJECTIVE Surgical approaches for the mobilization of impacted teeth involve the use of gold chains to connect the impacted tooth with the orthodontic appliance. In this study we have compared the local effects gold plated stainless steel with stainless steel specimen using an in vitro model of the gingival mucosa and monolayer cultures of cells of the alveolus. STUDY DESIGN Local effects on differentiation, proliferation, and apoptosis and inflammatory response were tested using organotypic cultures of gingival cells. Cytotoxicity was measured by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays with monolayer cultures of human periodontal cells. RESULTS The data obtained in this study could not reveal any differences in favor of using gold plated chains during the mobilization of impacted teeth. CONCLUSION For patients not suffering from allergies against nickel there might be no rationale to favor gold plated chains, as there are no functional aspects to favor gold plated chains over stainless steel chains.

Effects of Two Different Functional Appliances on Root Development of Posterior Teeth: Activator vs. Bite-jumping Appliance

Objective:The aim of this study was to investigate retrospectively the incidence of inhibited root development by metric analysis of orthopantomograms, based on examination of the posterior teeth of 40 children and adolescents with Angle Class II, Division 1 malocclusion who received two different removable functional appliances to treat the distal intermaxillary relationship.Patients and Methods:The patients were divided into two groups of equal size according to the appliance they wore for treatment (activator, bite-jumping appliance). Orthopantomograms for each patient were available from the start (time point T1) and after completion of the functional treatment (time point T2). Each radiograph’s enlargement factor in the posterior region was ascertained. The vestibular tooth lengths of the molars and premolars were then measured. To assess root length development, we determined the differences between tooth lengths at the start and after the end of the treatment.Results:Functional treatment generally led to an increase in tooth lengths in the anchorage region. Direct comparison of the two removable appliances revealed significant differences (p = 0.0478) in how much longer the maxillary first premolars became: following treatment with the activator, the teeth lengths increased by a mean of 2.64 mm ± 5.12 mm, whereas the mean increase in length after bite-jumping appliance therapy was 0.59 mm ± 3.40 mm.Conclusions:As a result of treatment with removable functional appliances, we observed locally different trends in root length increase in the posterior region in late-mixed and young adult dentitions, hence at a stage when root development had not concluded. The roots became longer during treatment with both the activator and bite-jumping appliance, but the maxillary first premolars’ root development varied widely. This may be because the bite-jumping appliance’s anchorage is right on the dentition, and the forces thus exert an immediate effect on the anchorage unit, particularly in the immediate vicinity of the protrusive bars in the maxilla. This led to certain groups of teeth to fail to achieve their entire potential length.ZusammenfassungZiel:Ziel der vorliegenden Studie war es, retrospektiv durch metrische Auswertung von Panoramaschichtaufnahmen die Seitenzähne von 40 Kindern und Jugendlichen mit einer Angle-Klasse- II/1-Anomalie, die zur Therapie des Distalbisses mit zwei verschiedenen herausnehmbaren funktionskieferorthopädischen Geräten behandelt wurden, auf das Vorkommen von Entwicklungshemmungen der Wurzeln zu untersuchen.Patienten und Methodik:Die Patienten konnten dem jeweiligen Behandlungsgerät (Aktivator, Vorschubdoppelplatte) entsprechend in zwei zahlenmäßig gleich große Gruppen unterteilt werden. Von jedem Patienten lagen Panoramaschichtaufnahmen vom Beginn (Zeitpunkt T1) und nach Abschluss der funktionskieferorthopädischen Behandlung (Zeitpunkt T2) vor. Für jedes Röntgenbild wurde die Vergrößerung des Seitenzahnbereichs individuell ermittelt. Danach erfolgte die Vermessung der vestibulären Zahnlängen der Molaren und Prämolaren. Zur Beurteilung der Entwicklung der Wurzellänge wurden die Differenzen aus den Zahnlängen zu Beginn und nach Abschluss der Behandlung gebildet.Ergebnisse:Unter der funktionskieferorthopädischen Behandlung kam es allgemein zu einer Zunahme der Zahnlängen im Verankerungsbereich. Im direkten Vergleich der beiden herausnehmbaren Apparaturen zeigten sich bei den ersten Prämolaren des Oberkiefers signifikante Unterschiede (p = 0,0478) im Ausmaß der Längenzunahme: Unter der Behandlung mit dem Aktivator nahmen die Zähne mit durchschnittlich 2,64 mm ± 5,12 mm in größerem Umfang an Länge zu als bei der Therapie mit der Vorschubdoppelplatte (0,59 mm ± 3,40 mm).Schlussfolgerungen:Bei der Behandlung mit herausnehmbaren funktionskieferorthopädischen Apparaturen zeigte sich im späten Wechselgebiss bzw. im jungen adulten Gebiss und somit zu einem Zeitpunkt, in dem das Wachstum der Wurzeln noch nicht vollständig abgeschlossen war, lokal unterschiedliche Tendenzen hinsichtlich der Wurzellängenzunahme im Seitenzahnbereich. Zwar nahmen sowohl unter der Behandlung mit einem Aktivator als auch mit einer Vorschubdoppelplatte die Längen der Wurzeln zu, doch war das Wurzelwachstum der ersten Prämolaren des Oberkiefers unterschiedlich stark. Ursächlich könnte sein, dass die direkte Verankerung der Vorschubdoppelplatte an der Dentition und damit die unmittelbare Krafteinwirkung auf die Verankerungseinheit insbesondere in unmittelbarer Nähe der Vorschubstege im Oberkiefer dazu führten, dass einzelne Zahngruppen nicht ihre vollständige, potentiell mögliche Länge erreichten.

Reliable coupling of orthodontic elements to mini-implants: An in-vitro study

Objectives: To investigate the reliability of mechanical and adhesive methods of fixing rectangular wires in the cross-slot of a mini-implant. Materials and Methods: A twin-hooked wire element was placed and fixed in the slot of a mini-implant via a NiTi spring under tension, or by means of an adhesive. For the purpose of mechanical anchorage, the wire was crimped with a special crimping tool to increase its thickness and prevent it from slipping through the slot. Before applying the adhesive, there were four possible methods of preparation: Untreated Wire (Adh. 1); ROCATEC-Pre (Adh. 2); ROCATEC-PRE + Espe Sil (Adh. 3); ROCATEC-PRE + ROCATEC-PLUS + Espe Sil (Adh. 4). The mechanical fixing and two adhesive fixings were aged by means of temperature change (500 cycles). A Zwick universal testing machine was used to measure the maximum strength of the coupling. Results: In all tests, the untreated wire + adhesive withstood the lowest maximum load (Ø 3 N and 10.8 N respectively) and failed the aging test after a maximum of eight cycles. The wires in test group Adh. 4 withstood the highest maximum load (Ø 43.3 N; 41.5 N; 45.9 N after aging) in all tests. The average load withstood by the crimped ligature was 38.7 N. Conclusion: The adhesive method of fixation performs best when the rectangular wire is sand blasted and silanized before application. The mechanical coupling using the crimped ligature is reliable.