Shear bond strengths of seven self-etching primers after thermo-cycling

Objective: Self-etching primers are widely used in restorative dentistry. However, only one primer has been developed for orthodontic applications. The objective of this study was to assess the suitabiliy of restorative self-etching primers on unabraded enamel. Material and Methods: Seven self-etching primers (Transbond™ SEP +, Xeno®III, Clearfil™SE, Futurabond®NR, OneCoat, M-Bond and OptiBond®) were compared with two conventionally-etched control groups (Transbond™ MIP). All groups with the exception of one of the two control groups underwent thermo-cycling (1000x, 5-55°C). Bovine teeth stored in physiological saline solution were used for the purpose of this study. Results: Both before and after thermo-cycling, the control groups presented very similar shear strengths which did not differ significantly from each other or from the Transbond™ SEP +  and Clearfil™SE specimens. During thermo-cycling, all groups except the control group and the Transbond™ SEP +  specimens displayed losses from the shear bodies. These losses occurred on all of the OptiBond® samples. The adhesive remnant index (ARI) and enamel tear-outs correlated closely with the adhesive values. Conclusions: Our adhesive value assessments support the conclusion that only Transbond™ SEP +  and Clearfil™SE can be recommended for clinical us

Development and BiomechanicalInvestigation of a New Compound Palatal Arch

Abstract. : Background and Aim: : There are many advantages in using a transpalatal arch in orthodontic treatment. In addition to the active movement of individual teeth, such an arch can be used to provide additional anchorage. The aim of this study was to further develop and improve both the clinical and the biomechanical properties of the conventional transpalatal arch. Material and Methods: : Currently available compound material components form an established part of orthodontic therapy. The Compound palatal arch® broadens the scope of this treatment system. The biomechanical effects of the newly developed Compound palatal arch® were verified by comparing them with those of commercially available conventional transpalatal arches. The recently developed Compound palatal arch® is made of one compound element: nickel-titanium/stainless steel. The specific dimensions and design of the nickel-titanium element are aimed at exploiting its superelasticity, even during active molar movement. The biomechanical investigation was carried out using sixcomponent measuring sensors to register the forces and moments in the three spatial dimensions (x, y and z) at 37 °C. The following appliances were investigated: Goshgarian transpalatal arch, quad-helix appliance, Arndt memory expander®, and Compound palatal arch®. Results: : Transpalatal arches could not be inserted without the arch being under tension. This is particularly important when the arch is being used for anchorage purposes. The Goshgarian arch had to be classified as problematic for the movement of single teeth as the load/deflection rate was high. However, this can be utilized for anchorage purposes. The clinical advantage of a quad-helix appliance is the option for asymmetric tooth movement. Conclusions: : This study showed that the quad-helix was effective for both unilateral and bilateral derotation as well as for transversal tooth movement. However, expansions should be confined to ≤ 4 mm, and derotations to < 10°, as forces and moments are otherwise not within the physiologic range. The Arndt memory expander® displayed no advantages over either the quad-helix appliance or the Goshgarian transpalatal arch. Nor did it display any superelastic properties. The linear relationship, the relatively high forces and moments, and the lack of clinical adjustability cast doubts on the benefits of this appliance. The newly developed Compound palatal arch® showed substantial advantages in molar derotation compared with conventional transpalatal arches. Superelastic properties were achieved through the design and positioning of the nickel-titanium element. Expansion with the Compound palatal arch® was comparable with that with conventional transpalatal arches. The clinical advantage is in the fact that this appliance can be reactivated and that dental asymmetries can be treate

Dynamic Functional ForceMeasurements on an Anterior Bite Plane during theNight

Abstract. : Background: : Anterior bite planes are used in removable and fixed appliance treatment. In removable appliance treatment the question arising is whether the delivered forces can achieve active intrusion in terms of their amplitude and duration. In fixed appliance treatment, the force effect on the incisors and associated pathologic side effects, in particular under the application of intrusion mechanics, have to be considered. Subjects and Method: : The aim of the present study was to investigate the effects of an anterior bite plane during the night. For this purpose ten subjects underwent nocturnal sleep investigations by means of a telemetric system. A silicon force sensor was integrated into an anterior bite plane for continuous measurement of bite forces and of the frequency of occlusal contact with the plate. Results: : The occlusal forces exerted on the anterior bite planes ranged between 3 and 80 N. The average forces were 5.5-24 N. The number of occlusal contacts varied between 39 and 558, with forces of between 7 and 9 N being registered in most cases. Major interindividual differences were detected in the magnitude of the force as well as in bite frequency. The intraindividual pattern of arising occlusal forces showed an intermittent force effect. No significant differences were found with regard to gender or growth pattern. Conclusions: : In subjects with removable appliances, no active intrusion of teeth is possible during the night owing to the small number of occlusal contacts. Due to the partially very high forces in fixed appliance therapy, the integration of an anterior bite plane has to be assessed as critical in patients with unfavorable root geometry or bruxis

Sitzung vom 9. Mai 1910

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Sitzung vom 14. November 1910

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Influence of Enamel Conditioning on the Shear Bond Strength of Different Adhesives

Abstract : Background and Objective: : Phosphoric acid etching is the gold standard for enamel conditioning. However, it is possible that air abrasion or a combination of air abrasion and etching might result in enhanced adhesion. The aim of this study was to investigate the effect of different enamel conditioning methods on the bond strength of six adhesives. Material and Methods: : Three different enamel conditioning procedures (phosphoric acid etching, air abrasion, air abrasion + phosphoric acid etching) were evaluated for their influence on the shear bond strength of six different adhesives (Transbond™ XT, Cool-Bond™, Fuji Ortho LC, Ultra Band-Lok, Tetric® Flow, Light-Bond™). Each group consisted of 15 specimens. Shear forces were measured with a universal testing machine. The scores of the Adhesive Remnant Index (ARI) were also analyzed. Results: : There were no significant differences between phosphoric acid etching and air abrasion + phosphoric acid etching. Air abrasion as a single conditioning technique led to significantly lower shear forces. The ARI scores did not correlate with the shear strengths measured. There were greater variations in shear forces for the different adhesives than for the conditioning techniques. Conclusion: : The highest shear forces were found for the conventional composites Transbond™ XT and Cool- Bond™ in combination with conventional etching. Air abrasion alone and in combination with phosphoric acid etching showed no advantages compared with phosphoric acid etching alone and, therefore, cannot be recommende

Corrosion of Orthodontic Pliers Using Different Sterilization Procedures

Abstract : Aim: : The aim of this study was to investigate the corrosion resistance of orthodontic pliers from several manufacturers following different sterilization procedures, namely heat sterilization and the use of a disinfectant agent (Sekusept Extra N®) in an ultrasonic bath. Material and Methods: : Employed in this study were ten distal-end cutters and ten Weingart pliers manufactured by Aesculap®, ETM and Hu-Friedy®, examined under electron microscopy for evidence of corrosion following 500 sterilization cycles. The corrosion data were recorded photographically and graphically. Metallographic microsections were prepared from each pair of pliers and were then analyzed by means of EDX measurements to assess the chemical alloy composition. Results: : The light and electron microscopic evaluation showed that both heat sterilization and high level disinfection caused corrosive changes on the pliers. However, the type of corrosion differed between the two sterilization methods. The main type of corrosion with Sekusept Extra N® was pitting, while with heat sterilization it was surface corrosion. Heat sterilization was the type of corrosion that caused the most corrosive changes, regardless of which type of corrosion was considered. However, these results must be viewed critically, because pitting corrosion is obviously a more severe problem than surface corrosion. In comparing the pliers of various manufacturers, differences were noted. However, it was difficult to rank them when the correct maintenance regime was adhered to. The soldered joint gap was revealed to be a specific weak point, and that area proved to be inadequate due to qualities related to their production, particularly in the Hu-Friedy® pliers. Conclusions: : This study showed that heat sterilization leads to less corrosion than cold disinfection. Corroded pliers can be restored to a useable condition by re-polishing, though it is important that the instructions for their care be strictly adhered t