Thomas Ziebura

Accidental debondings: Buccal vs fully individualized lingual multibracket appliances.

INTRODUCTION The aim of this study was to retrospectively assess the frequency and localizations of bond failures (BFs) in patients treated with either lingual (TOP-Service für Lingualtechnik GmbH, a 3M Company, Bad Essen, Germany) or buccal (Mini Diamond brackets/Accent molar tubes; Ormco, Orange, Calif) full multibracket appliances in both dental arches. METHODS Data were acquired by an independent investigator from the patient records of 3 practitioners. To establish a standardized observation period, the first year of treatment was analyzed for each patient. Statistical analysis comprised the Kruskal-Wallis, Wilcoxon, Mann-Whitney U, and Fisher exact tests. The significance level was set at P <0.05. RESULTS The mean number of BFs per patient in the first year of treatment did not differ significantly between the lingual group (n = 59; mean age, 31.1 years; mean BFs per patient, 2.63; SD, 2.77; minimum, 0; maximum, 13) and the buccal group (n = 44; mean age, 15.14 years; mean BFs per patient, 2.61; SD, 3.41; minimum, 0; maximum, 14) (P = 0.428) or with respect to sex (lingual group, P = 0.251; buccal group, P = 0.414) or practitioner (lingual group, P = 0.755; buccal group, P = 0.060), but molar attachments were more prone to BFs than were premolar brackets (lingual group, P = 0.015; buccal group, P = 0.049), and premolar brackets were more prone to BF than anterior brackets (lingual group, P = 0.005; buccal group, P = 0.004). CONCLUSIONS With both appliances, a mean of 2.62 BFs per patient in the first year of treatment can be expected; this benchmark provides a reference for patient briefing, which is very important considering the large interindividual variances and budgeting considerations.

In-vitro investigation on suitability of light-cured resins for interocclusal splints : part II: surface hardness.

Objective:The aim of the present study was to determine the surface hardness of light- and auto-cured resins for the fabrication of occlusal splints employing Vickers hardness measurements.Materials and Method:In this study we used three auto-polymerized resins (Palapress®, Orthocryl®, Steady-Resin® M) and four light-polymerized resins (Acrylight®, Primosplint®, Triad® Tran- Sheet® Colorless and Triad® TranSheet® Pink). The Vickers hardness measurement was carried out by means of a universal Durimet indenter applying a test load of 50 g for 30 seconds. The light-cured resins were polymerized in a Tagris® Power light oven for 10 and 15 minutes each. Three separate test series were carried out (the hardness of plates under optimal conditions and of occlusal splints was measured, and the curing of light-polymerizing materials in layers of varying depth was evaluated). Data underwent statistical analysis via ANOVA and the Scheffé test.Results:The microhardness determined in each case amounted to values between 10.4 HV 0.5 and 39.3 HV 0.5. The Vickers hardness determined for the plates that had been produced under optimal conditions demonstrated that their surface was significantly (p < 0.05) harder than that of cylinders and splints. The hardness values of the light-cured material Triad® TranSheet® Pink (39.3 HV 0.5) were significantly higher (p < 0.05) than those of all other resins. In all auto-polymerized resins, the surface hardness of the samples we examined (in the form of plates and splints) was significantly lower (p < 0.05) than that of the light-cured materials Triad® TranSheet® Pink and Colorless.Conclusion:The results we have obtained so far concerning surface hardness indicate that, in the fabrication of occlusal splints, light-cured resins may represent an alternative to auto-polymerizing materials.ZusammenfassungZiel:In der vorliegenden Studie sollte mit Hilfe von Vickers-Härtemessungen die Oberflächenhärte von Licht- und Autopolymerisaten für die Herstellung okklusaler Splinte ermittelt werden.Material und Methode:Es wurden drei Autopolymerisate (Palapress®, Orthocryl®, Steady-Resin® M) und vier Lichtpolymerisate (Acrylight®, Primosplint®, Triad® TranSheet® Colorless und Triad® TranSheet® Pink) verwendet. Für die Vickers-Härtemessung kam das Kleinlasthärteprüfgerät Durimet mit einer Prüflast von 50 g für 30 s zum Einsatz. Die Polymerisation der lichthärtenden Kunststoffe erfolgte im Lichtofen Tagris® Power für jeweils 10 und 15 Minuten. Drei verschiedene Versuchsreihen wurden durchgeführt (Härtemessung an Plättchen unter Idealbedingung, Härtemessung an okklusalen Splinten sowie Ermittlung der Durchhärtung der lichthärtenden Materialien in verschiedenen Schichttiefen). Es erfolgte eine statistische Auswertung der Daten nach dem ANOVA- und dem Scheffé-Test.Ergebnisse:Die ermittelten Mikrohärten für die Plättchen lagen zwischen 10,4 HV 0,5 und 39,3 HV 0,5. Die für die unter idealisierten Bedingung angefertigten Plättchen festgestellte Vickers-Härte ergab eine signifikant größere (p < 0,05) Oberflächenhärte als für Zylinder und Splinte. Die Härtewerte für das lichthärtende Material Triad® TranSheet® Pink (39,3 HV 0,5) waren signifikant (p < 0,05) höher als die aller anderen Kunststoffe. Die Oberflächenhärte der untersuchten Proben (in Form von Plättchen und Splinten) lag für alle Autopolymerisate signifikant (p < 0,05) unter jener der lichthärtenden Materialien Triad® TranSheet® Pink und Colorless.Schlussfolgerung:Die bisher gewonnenen Ergebnisse bezüglich der Oberflächenhärte deuten darauf hin, dass die lichthärtenden Kunststoffe bei der Herstellung okklusaler Splinte eine Alternative zu den autopolymerisierenden Kunststoffen darstellen können.

The university münster model surgery system for orthognathic surgery. Part II – KD-MMS

BackgroundModel surgery is an integral part of the planning procedure in orthognathic surgery. Most concepts comprise cutting the dental cast off its socket. The standardized spacer plates of the KD-MMS provide for a non-destructive, reversible and reproducible means of maxillary and/or mandibular plaster cast separation.MethodsIn the course of development of the system various articulator types were evaluated with regard to their capability to provide a means of realizing the concepts comprised of the KD-MMS. Special attention was dedicated to the ability to perform three-dimensional displacements without cutting of plaster casts. Various utilities were developed to facilitate maxillary displacement in accordance to the planning. Objectives of this development comprised the ability to implement the values established in the course of two-dimensional ceph planning.ResultsThe system - KD-MMS comprises a set of hardware components as well as a defined procedure. Essential hardware components are red spacer and blue mounting plates. The blue mounting plates replace the standard yellow SAM mounting elements. The red spacers provide for a defined leeway of 8 mm for three-dimensional movements. The non-destructive approach of the KD-MMS makes it possible to conduct different model surgeries with the same plaster casts as well as to restore the initial, pre-surgical situation at any time. Thereby, surgical protocol generation and gnathologic splint construction are facilitated.ConclusionsThe KD-MMS hardware components in conjunction with the defined procedures are capable of increasing efficiency and accuracy of model surgery and splint construction. In cases where different surgical approaches need to be evaluated in the course of model surgery, a significant reduction of chair time may be achieved.

A simplified approach to true molar intrusion.

BackgroundOrthodontic management of anterior open bites is a demanding task for orthodontists. Molar intrusion as a primary means of open bite correction entails the need for appropriate anchorage. Orthodontic mini implants can provide the required mechanical support. The suggested procedure aims to reduce the risk of complications such as root damage or soft tissue irritations while minimizing overall complexity.MethodsThree female patients aged 14, 18 and 19 years who decided against a surgical correction were treated with a device consisting of mini implants in the palatal slope, a palatal bar and intrusion cantilevers.ResultsIn all three patients, an open bite reduction of more than a millimeter occurred within four months. An anterior overbite of 2 mm or more could be established within 6 to 9 months.ConclusionsThe method presented in this article enables the practitioner to use mini implants in an easily accessible insertion site. A lab-side procedure is optional but not required.

Mini-implants in the palatal slope – a retrospective analysis of implant survival and tissue reaction

BackgroundTo identify insertion procedure and force application related complications in Jet Screw (JS) type mini-implants when inserted in the palatal slope.MethodsSetting and Sample Population: The Department of Orthodontics, the University Hospital Münster. Forty-one consecutively started patients treated using mini-implants in the palatal slope. In this retrospective study, 66 JS were evaluated. Patient records were used to obtain data on the mode of utilization and complications. Standardized photographs overlayed with a virtual grid served to test the hypothesis that deviations from the recommended insertion site or the type of mechanics applied might be related to complications regarding bleeding, gingival overgrowth or implant failure.ResultsTwo implants (3%) were lost, and two implants (3%), both loaded with a laterally directed force, exhibited loosening while still serving for anchorage. Complications that required treatment did not occur, the most severe problem observed being gingival proliferation which was attributable neither to patients’ age nor to applied mechanics or deviations from the ideal implant position.ConclusionsThe JS mini-implant is reliable for sagittal and vertical movements or anchorage purposes. Laterally directed forces might be unfavorable. The selection of implant length as well as the insertion procedure should account for the possibility of gingival overgrowth.

In-vitro Investigations on Suitability of Light-cured Resins for Interocclusal Splints@@@In-vitro-Untersuchungen zur Eignung lichthärtender Kunststoffe für interokklusale Aufbissschiene: Part I: Mechanical Properties@@@Teil I: Mechanische Eigenschaften

Objective:It was the aim of the present study to investigate the material properties of different resins and their suitability for the fabrication of occlusal and intermaxillary splints.Material and Method:We subjected auto-polymerized resins (Palapress®, Orthocryl®, Steady-Resin® M) and light-polymerized resins (Acrylight®, Primosplint®, Triad® TranSheet® Colorless and Pink) to investigation. The Targis® Power light oven was used to polymerize the light-cured resins. After the auto-polymerized resins had been mixed by hand and filled into the forms, they were polymerized for 15 minutes in a high-pressure polymerization machine (Palamat®) at 2 bar. The parameters examined were flexural strength, water adsorption, and polymerization shrinkage. Tests carried out according to DIN EN ISO 1567 served to determine flexural strength, flexural modulus, and water adsorption. Polymerization shrinkage was determined via the buoyancy test.Results:The resins’ flexural strength ranged from 60 to 101 MPa. Flexural moduli lay between 1.3 and 5.3 GPa. The water adsorption noted in light-cured resins amounted to 2.1–4.6 mass percent. Palapress® and Steady-Resin® displayed the lowest water adsorption with 2.0 mass percent. The light-polymerized resins revealed significantly less shrinkage (p < 0.05) than the autopolymerized resins tested in this study.Conclusion:Our results demonstrate that the light-cured resins—with the exception of Acrylight®—easily match and even exceed the material properties of the cold-polymerized resins regarding flexural strength, flexural modulus, water adsorption and polymerization shrinkage. The light-cured resins examined thus seem suitable for use as splint material.ZusammenfassungZiel:Gegenstand der vorliegenden Arbeit war die werkstoffkundliche Eignung verschiedener Kunststoffe zur Herstellung von Aufbissschienen sowie von intermaxillären Splinten.Material und Methode:Untersucht wurden autopolymerisierende (Palapress®, Orthocryl®, Steady-Resin® M) sowie lichtpolymerisierende Kunststoffe (Acrylight®, Primosplint®, Triad® Tran-Sheet® Colorless und Pink). Bei der Polymerisation der lichthärtenden Kunststoffe im Halogen- und UVA-Bereich kam der Lichtofen Targis Power® zur Anwendung. Die Autopolymerisate wurden nach dem manuellen Anmischen und dem Einfüllen in Formen für 15 Minuten unter 2 bar in einem Drucktopf (Palamat®) auspolymerisiert. Als Untersuchungsparameter wurden Biegefestigkeit, E-Modul, Wasseraufnahme sowie Polymerisationsschrumpfung herangezogen. Versuche gemäß DIN EN ISO 1567 dienten zur Ermittlung von Biegefestigkeit, E-Modul und Wasseraufnahme. Die Bestimmung der Polymerisationsschrumpfung erfolgte mittels Auftriebverfahren.Ergebnisse:Die Biegefestigkeit der untersuchten Kunststoffe lag in einem Bereich von 60 bis 101 MPa. Die ermittelten Elastizitätsmodule lagen zwischen 1,3 und 5,3 GPa. Die bei den lichthärtenden Kunststoffen festgestellte Wasseraufnahme betrug 2,1–4,6 Mass.-%. Palapress® und Steady-Resin® wiesen mit 2,0 Mass.-% die niedrigste Wasseraufnahme auf. Im Vergleich zu den hier getesteten Autopolymerisaten zeigten die Lichtpolymerisate eine signifikant (p < 0,05) niedrigere Schrumpfung.Schlussfolgerung:Die eigenen Ergebnisse verdeutlichen, dass die lichthärtenden Kunststoffe bis auf Acrylight® durchaus die Werkstoffeigenschaften der Kaltpolymerisate hinsichtlich der Biegefestigkeit, des E-Moduls, der Wasseraufnahme sowie der Polymerisationsschrumpfung erreichen oder sogar übertreffen können. Somit erscheinen die untersuchten lichthärtenden Kunststoffe für den Einsatz als Schienenwerkstoff geeignet.

In-vitro Investigations on Suitability of Light-cured Resins for Interocclusal Splints

Objective:It was the aim of the present study to investigate the material properties of different resins and their suitability for the fabrication of occlusal and intermaxillary splints.Material and Method:We subjected auto-polymerized resins (Palapress®, Orthocryl®, Steady-Resin® M) and light-polymerized resins (Acrylight®, Primosplint®, Triad® TranSheet® Colorless and Pink) to investigation. The Targis® Power light oven was used to polymerize the light-cured resins. After the auto-polymerized resins had been mixed by hand and filled into the forms, they were polymerized for 15 minutes in a high-pressure polymerization machine (Palamat®) at 2 bar. The parameters examined were flexural strength, water adsorption, and polymerization shrinkage. Tests carried out according to DIN EN ISO 1567 served to determine flexural strength, flexural modulus, and water adsorption. Polymerization shrinkage was determined via the buoyancy test.Results:The resins’ flexural strength ranged from 60 to 101 MPa. Flexural moduli lay between 1.3 and 5.3 GPa. The water adsorption noted in light-cured resins amounted to 2.1–4.6 mass percent. Palapress® and Steady-Resin® displayed the lowest water adsorption with 2.0 mass percent. The light-polymerized resins revealed significantly less shrinkage (p < 0.05) than the autopolymerized resins tested in this study.Conclusion:Our results demonstrate that the light-cured resins—with the exception of Acrylight®—easily match and even exceed the material properties of the cold-polymerized resins regarding flexural strength, flexural modulus, water adsorption and polymerization shrinkage. The light-cured resins examined thus seem suitable for use as splint material.ZusammenfassungZiel:Gegenstand der vorliegenden Arbeit war die werkstoffkundliche Eignung verschiedener Kunststoffe zur Herstellung von Aufbissschienen sowie von intermaxillären Splinten.Material und Methode:Untersucht wurden autopolymerisierende (Palapress®, Orthocryl®, Steady-Resin® M) sowie lichtpolymerisierende Kunststoffe (Acrylight®, Primosplint®, Triad® Tran-Sheet® Colorless und Pink). Bei der Polymerisation der lichthärtenden Kunststoffe im Halogen- und UVA-Bereich kam der Lichtofen Targis Power® zur Anwendung. Die Autopolymerisate wurden nach dem manuellen Anmischen und dem Einfüllen in Formen für 15 Minuten unter 2 bar in einem Drucktopf (Palamat®) auspolymerisiert. Als Untersuchungsparameter wurden Biegefestigkeit, E-Modul, Wasseraufnahme sowie Polymerisationsschrumpfung herangezogen. Versuche gemäß DIN EN ISO 1567 dienten zur Ermittlung von Biegefestigkeit, E-Modul und Wasseraufnahme. Die Bestimmung der Polymerisationsschrumpfung erfolgte mittels Auftriebverfahren.Ergebnisse:Die Biegefestigkeit der untersuchten Kunststoffe lag in einem Bereich von 60 bis 101 MPa. Die ermittelten Elastizitätsmodule lagen zwischen 1,3 und 5,3 GPa. Die bei den lichthärtenden Kunststoffen festgestellte Wasseraufnahme betrug 2,1–4,6 Mass.-%. Palapress® und Steady-Resin® wiesen mit 2,0 Mass.-% die niedrigste Wasseraufnahme auf. Im Vergleich zu den hier getesteten Autopolymerisaten zeigten die Lichtpolymerisate eine signifikant (p < 0,05) niedrigere Schrumpfung.Schlussfolgerung:Die eigenen Ergebnisse verdeutlichen, dass die lichthärtenden Kunststoffe bis auf Acrylight® durchaus die Werkstoffeigenschaften der Kaltpolymerisate hinsichtlich der Biegefestigkeit, des E-Moduls, der Wasseraufnahme sowie der Polymerisationsschrumpfung erreichen oder sogar übertreffen können. Somit erscheinen die untersuchten lichthärtenden Kunststoffe für den Einsatz als Schienenwerkstoff geeignet.