ObjectivesTo investigate the skeletal and dental changes during chincup versus facemask treatment, to compare the long-term effects of the two appliances, and to document the impact of each on treatment success.MethodsIn all, 61 patients with Class III syndrome were retrospectively analyzed at three examination times: 7.8 ± 1.7 years of age (T0, pretreatment), 9.6 ± 2.4 years of age (T1, posttreatment), and around 15–20 years later (T2, long-term follow-up).ResultsSignificant changes of specific cephalometric parameters for all treatment times: T0–T1 (SNA, interbase and gonial angle, Björk’s sum angle, maxillomandibular differential, and distance of upper lip to esthetic line), T1–T2 (NL-NSL, SNB, mandibular-body length, effective mandibular length, and effective maxillary length), and T0–T2 (mandibular-body length, effective mandibular length, effective maxillary length, maxillomandibular differential, SNB, ANB, gonial angle, Björk’s sum angle, and Wits appraisal). The T1–T2 results illustrate that in both treatment groups the typical Class III growth pattern often reappeared after treatment, including gains in SNB angle, condylion-gnathion length, and gonion-menton distance.ConclusionsEither a facemask or a chincup may be effectively used to treat Class III malocclusion. There were differences in long-term stability. Maxillary development was similarly favorable in both groups of patients with successful outcome. The subgroup in whom chincup treatment had failed were mainly characterized by excessive mandibular growth, or lack of maxillary catch-up growth, with deterioration of the maxillomandibular relationship notably in the initial phase of treatment. Early chincup treatment did not have an adverse impact on the temporomandibular joints.

AimThe present study evaluated the temporal release of Co Cr, Mn, and Ni from the components of a typical orthodontic appliance during simulated orthodontic treatment.Materials and methodsSeveral commercially available types of bands, brackets, and wires were exposed to an artificial saliva solution for at least 44 days and the metals released were quantified in regular intervals using inductively coupled plasma quadrupole mass spectrometry (ICP-MS, Elan DRC+, Perkin Elmer, USA). Corrosion products encountered on some products were investigated by a scanning electron microscope equipped with an energy dispersive X-ray microanalyzer (EDX).ResultsBands released the largest quantities of Co, Cr, Mn, and Ni, followed by brackets and wires. Three different temporal metal release profiles were observed: (1) constant, though not necessarily linear release, (2) saturation (metal release stopped after a certain time), and (3) an intermediate release profile that showed signs of saturation without reaching saturation. These temporal metal liberation profiles were found to be strongly dependent on the individual test pieces. The corrosion products which developed on some of the bands after a 6-month immersion in artificial saliva and the different metal release profiles of the investigated bands were traced back to different attachments welded onto the bands.ConclusionThe use of constant release rates will clearly underestimate metal intake by the patient during the first couple of days and overestimate exposure during the remainder of the treatment which is usually several months long. While our data are consistent with heavy metal release by orthodontic materials at levels well below typical dietary intake, we nevertheless recommend the use of titanium brackets and replacement of the band with a tube in cases of severe Ni or Cr allergy.

Rapid maxillary expansion distinctly increased mean palatal widths and cross-sectional areas. However, palatal height (55-65) and maxillary length decreased to a small extent.

In order to apply high, short-term forces during rapid maxillary expansion (RME) to the sutures of the maxilla with minimum loss of force and without causing unwanted side-effects (dentoalveolar tipping, etc.), the appliance should be as rigid as possible. The retention arms of the RME screws, representing a particularly vulnerable and stressed weak point of RME appliances, were the focus of this laboratory technical study. Retention arms of 16 types of RME screws comprising four arms and one with eight arms were examined using a three-point bending test. According to their ability to absorb the applied bending loads, the screws were classified in product groups from 1 (highest) to 6 (lowest). Fifteen of the tested retention arms (stainless steel), despite having the same diameter (1.48-1.49 mm), differed up to 69.81 per cent between the highest (288.0 N) and lowest (169.6 N) maximum force parameters and up to 66.40 per cent between the highest (3325.9 N/mm(2)) and lowest (1998.7 N/mm(2)) maximum bending stress parameters. Due to optimum formability, though reduced rigidity, a titanium screw for nickel-sensitive patients (group 6) displayed the lowest force and bending tension values. The stainless steel double arms of the eight-arm screw device welded on both ends displayed the highest force data. The mean ductilities of the groups with the most and least rigid single steel arms differed by 22.77 per cent. Statistical analysis using the Pearson correlation coefficient revealed a significant indirect correlation between ductility and both maximum force (r = -0.780, P < 0.001) and maximum bending stress (r = -0.778, P < 0.001). The SUPERscrews, the Tiger Dental four-arm screw (group 1), and the eight-arm screw displayed the highest capacity to absorb an applied bending load. The screws in groups 3-6 appear acceptable for RME during the pre-pubertal period, whereas in the pubertal and post-pubertal period, groups 1 and 2 are sufficient. In early adulthood only the screws in group 1 and especially the eight-arm screw seem advisable, as mechanical demands increase with age.

Zusammenfassung Es wird der Prototyp einer Non-Compliance-Apparatur vorgestellt, mit der eine k?rperliche Distalisation der Molaren erzielt werden kann. Der TopJet-Prototyp besteht aus einer Druckfeder, die 2 in ihr liegende Dr?hte auseinander schiebt. Die Apparatur wird an einer im Gaumen paramedian verankerten Dual-Top Jet-Schraube dreh- und winkelstabil verankert. Der andere Draht wird scharnierartig mit dem Transpalatinalbogen (TPA) verbunden, wodurch ein Kippen der Molaren w?hrend der Distalisation verhindert wird. Vorteile des TopJet-Konzepts sind das einfache Anklippen des Kraft-Applikators an den Schraubenkopf, die individuelle Anpassung zum TPA, die konstruktionsbedingte Stabilisierung der Molaren gegen Kippung und die reibungsfreie ?bertragung der Druckkraft. Der bei anderen Apparaturen notwendige Laborschritt zur individuellen Anpassung kann eingespart und die Stuhlzeit verk?rzt werden. Der TopJet-Prototyp wurde zwischenzeitlich zum ?TopJet-Distalizer? weiterentwickelt.