Tongue reduction in Beckwith-Wiedemann syndrome: outcome and treatment algorithm.

Beckwith-Wiedemann syndrome is a rare congenital overgrowth disorder with macroglossia being one of the cardinal symptoms. In pronounced cases, macroglossia can lead to airway obstruction, musculoskeletal alterations and functional deficits. Surgical tongue reduction is performed at varying ages and with different techniques. This study evaluated perioperative complications, as well as long-term aesthetic and functional outcomes, in a large cohort. A total of 68 patients, treated either surgically or conservatively, were included. Depending on the severity of macroglossia, patients were divided into three groups to determine the treatment algorithm. Complications after surgical tongue reduction were prolonged intubation and revision due to dehiscence or haematoma. In the long term, no patient suffered from impaired sense of taste or paresthesia, although the shape of the tongue was disproportional in 85%. With the present treatment algorithm, operative tongue reduction exerts a positive influence on skeletal, dentoalveolar and functional development with sufficient long-term outcome and high grade of satisfaction of the patients. Supportive therapy in an interdisciplinary centre is of fundamental importance for both surgical and conservative treatment.

Precision of cephalometric analysis via fully and semiautomatic evaluation of digital lateral cephalographs.

OBJECTIVES: The aim of this study was to evaluate the precision of the cephalometric analysis using the orthodontic software Orthometric((R)) in two modes: fully automatic without any help by the user and semiautomatic with manual determination of all cephalometric landmarks. METHODS: From 100 indirectly digitally produced cephalographs, 72 were chosen randomly. On each one of these, three methods were applied on 12 decision-relevant cephalometric angles according to Hasund/Segner: (1) hand drawing on a transparent sheet over the cephalographic film; (2) software semiautomatically with manual correction on the screen; and (3) fully automatically. The hand-based method (1) is well established as a quality standard and reference. The angle measurement results of this method were compared with those of the semiautomatic and the fully automatic method by calculation of the mean absolute differences. Additionally, five randomly chosen cephalographs were evaluated ten times using all three methods for statistical evaluation of reproducibility. RESULTS: At tenfold evaluation of five cephalographs, the standard deviations of the angles were between 0.05 degrees and 0.8 degrees . These results were similar using all three methods. All three methods had similar reproducibility. At evaluation of 72 cephalographs, the mean absolute angle differences between the hand-based (1) and semiautomatic (2) methods were below 2 degrees and so within the allowed tolerance limit, except for the nasolabial angle. In contrast to this, all mean absolute angle differences between the (1) hand-based and (3) fully automatic methods exceeded 2 degrees , and with this the tolerance limit allowed by literature. CONCLUSIONS: The fully automatic determination of the cephalometric landmarks has led to relevant errors up to now, so that it is mandatory to check all automatically set landmarks and to correct them if required. In the case of the semiautomatic method, all relevant angles can be determined with the same reliability as hand drawing.

[A whole new development from the Bending Art System]. / Les toutes nouvelles évolutions du Bending Art System.

The system SureSmile (from Orametrix) has been developed on the basis of the Bending Art System (BAS) introduced in 1994 of which it is a manifold important evolution. It is a well considered combination of three-dimensional image processing, computer-assisted diagnosis, planning and realization of the treatment, which permits high quality orthodontia nevertheless capable of being reproduced in an objective manner. This article presents the system SureSmile.

Torque transmission between square wire and bracket as a function of measurement, form and hardness parameters.

The aim of the study was to investigate the influence of cross section, edge geometry and structural hardness on torque transmission between square wire and bracket. For this purpose, 5 different brands of stainless steel square wire in 3 dimensions (0.016" x 0.016", 0.016" x 0.022" and 0.017" x 0.025") were inserted into edgewise brackets with a slot size of 0.018" and loaded with different torques (1 and 3 Ncm). The slot and wire geometries were analyzed by computer on ground specimens before and after loading. In addition, the Vickers hardness and micro-hardness of the unstressed and stressed metal surfaces were determined. While the slot size was very accurately maintained, the wire dimensions deviated downwards by an average of 10%. Torque transmission led to notching and bending-up phenomena on the bracket slot flanks. A torque loading of 3 Ncm increased the torque play of 0.016" x 0.022" wires by 3.6 degrees, and of 0.017" x 0.025" wires by 3.7 degrees. In the case of 0.016" x 0.016" wires, an effective torque transmission was no longer possible. The average Vickers hardness of the wires was 533 kp/mm2, and that of the brackets 145 kp/mm2. The micro-hardness in the deformation area of stressed internal slot walls increased with increasing load transmission from 204 to 338 kp/mm2. As a result of excessively small wire dimensions and plastic deformation of the brackets, a relatively large torque play occurs. Deformation and notching in the area of the internal slot walls are inconsistent with demands for recycling brackets. A standardization of bracket wire systems stating the actual torque play would be desirable.

Validity of the computer-assisted cephalometric growth prognosis VTO (Visual Treatment Objective) according to Ricketts.

The computer-assisted growth prognosis "Visual Treatment Objective" (VTO) according to Ricketts gives an individual prediction based on empirically obtained mean growth rates and includes the expected influence of orthodontic treatment. The objective of the present study was to investigate the validity of the VTO over a period of 2 and 5 years. For this purpose, lateral teleradiographic images of 180 patients were analyzed before the start and after the completion of active treatment, and the actual outcome was compared with the prognosis. For both prognostic periods, the VTO yielded a satisfactory prognosis of maxillary inclination, of the anteroposterior position of the maxilla, of growth in mandibular length, of the anteroposterior position and rotation of the mandible, of the positional relation of the mandible and maxilla, of basicranial configuration, and of vertical craniofacial development. For neither of the 2 prognostic periods did the VTO give a satisfactory prognosis of dental relations, of dentoskeletal relations or of soft-tissue configuration. The VTO is capable of giving a largely valid prognosis of skeletal growth tendencies. However, in view of the large number of parameters affected by therapeutic measures, the VTO prognosis must be expected to differ from the actual treatment outcome.

The force module for the bending art system. Preliminary results.

The force module for the bending art system (BAS) is used to calculate the initial forces and moments expected to act on a tooth after changing arch wires. The present study analyses the accuracy of the force module on the basis of 10 patients treated with the BAS (with an average observation period of 10 months). An average of 6 arch wires (0.16" x 0.016" steel) were used on each jaw. The approximate pressure in the periodontium was determined and statistically evaluated from the force module readings. The resulting average pressure values for the molars ranged between 0.26 N/cm2 and 0.54 N/cm2. The value in the area of the incisors, cuspids and bicuspids ranged between 1.03 N/cm2 and 2.83 N/cm2. Maximum pressure was 8.02 N/cm2. The results are discussed from a clinical point of view on a case-to-case basis. They are plausible in and for themselves. The more severe the initial state of misalignment, the higher the pressure values. These forces can be reduced by increasing the number of arch wires or by altering the form of the archwire correspondingly. The computer-generated values should be confirmed by taking a direct measurement on the tooth. The force module is just the first step in providing a reproducible estimation of the forces acting on a tooth. Even if the calculated absolute values should still be judged with reservation, they are nevertheless suitable for providing a comparative evaluation of various treatment concepts with reference to the forces acting on the periodontium and can serve clinicians as a rapidly available decision-making aid.

Continuous arch wire technique using the bending art system.

The bending art system (BAS) enables computerized production of individual arch wires for the multiband technique. Treatment planning using the continuous arch technique as part of the bending art system has been described. Planning of the arch wires follows an initial camera picture taken in the patient's mouth, and is divided into the following steps: ideal arch, target arch and course of treatment. The ideal arch establishes the individual shape of the arch wires in the horizontal plane. Based on the input of various small adjustments, the ideal arch is transformed into the target arch which represents the final arch of the treatment. Finally, the sequence of the various arches is established. The geometry of the intermediate arches is calculated on the assumption that each tooth is moved the shortest possible distance during transformation from the initial arch to the target arch. This procedure, called the direct method, is compared with the newly developed indirect method. With the indirect method, the camera picture is taken of the initial cast and the target arch is produced in accordance with a setup model in ideal occlusion. In contrast to the straight-wire technique, treatment with the BAS is not finalized with a straight arch wire since the occlusion of the individual patient rarely complies with the straight-wire norm.

Bending and torquing accuracy of the bending art system (BAS).

With the bending art system (BAS) the computerized production of individual arch wires has become possible. The BAS consists of an intraoral camera, a computer program and a bending machine producing the archwire by consecutive bending and twisting procedures. This study examines the accuracy of the bending machine when using 0.016" x 0.016" and 0.016" x 0.022" steel wire of rectangular cross-section. Bending angles ranging from 6 degrees to 54 degrees, and torsion angles ranging from 2 degrees to 35 degrees were tested; also the minimum distance between these individual operations was determined. The bent pieces of wire were analysed in a 3D-coordinate gauging system. The 0.016" x 0.016" steel wire showed a mean measuring error of 0.62 degree in bending procedures and of 0.72 degree in torsion procedures, whereas the 0.016" x 0.022" steel wire showed an error of 0.87 degree with edgewise bendings and of 0.86 degree with torsions. To ensure this accuracy a minimum distance of 0.5 mm to 0.7 mm, depending on which kind of bending combination is used, between bending and torsion is required. The error could be reduced even further if a more constant wire material and a more accurate calibration of the bending machine were used. All in all the precision of the bending machine meets the clinical requirements.

[Hardened anodized aluminum as a replacement material for bracket manufacture]. / Hartanodisiertes Aluminium als Ersatzwerkstoff für die Bracketherstellung.

Attention has been repeatedly drawn to the problem of corrosion and the risk of allergic reaction to nickel resulting from the use of stainless steel brackets. In the search for a suitable alternative, manufacturers have turned to thin coating technology using hardened anodized aluminium. Applying resistance to corrosion and abrasion as the criteria to be met, they have selected aluminium alloy type 6082 as the material of choice. Purpose of this study is to examine the physical suitability of this material. Using the above noted alloy, 60 prototype brackets were made with a hardened anodized surface. They were then subjected to the following 3 stress tests: first an abrasion test using a tooth polishing machine, second, a deformation test using a device designed to simulate torque movement, and, third, a corrosion test. The effects on the brackets resulting from the three types of stress were evaluated by light microscopy. A quantitative analysis of the corrosion test was performed by ICP spectrometry. The control group consisted of conventional stainless steel brackets. The light microscopic analysis revealed no evidence of surface damage or signs of deformation in the prototype brackets. The steel brackets, on the other hand, showed clear signs of wear and corrosion. The quantitative analysis of the corrosion solution revealed metallic ion wear of 1.75 ng x mm-2 x h-1 for the prototypes subjected to abrasion. The steel brackets showed at a factor of around 104.6 metallic ion wear of 183 ng x mm-2 x h-1. In addition to this, no Ni ions were found in the corrosion solution of the prototype brackets.(ABSTRACT TRUNCATED AT 250 WORDS)

[Enamel damage from multiple debonding in the bracket adhesion technic]. / Schmelzschäden bei Mehrfachdebonding in der Bracketadhäsivtechnik.

This study analyses the damage done by three debonding procedures. Ceramic brackets (ORMCO) having a basic size of 12.3 mm2 were bonded with Concise Composite to 120 non-carious premolars extracted from adolescent patients and subsequently shorn off using a Zwick multipurpose testing device. In 90 teeth the brackets were removed once, in 60 twice, and in 30 three times. The shearing forces were measured electronically and evaluated statistically. In a separate experiment involving 30 teeth, the in-depth interlinkage (adhesive "pegs") were exposed by chemically dissolving the enamel. The enamel surfaces and adhesive matrix were analysed using scanning electron microscopy. Each repeat debonding was associated with a clear increase in the frequency and size of the enamel damage. This was, on average, 12% (in four teeth) at the first debonding, 17.4% (six teeth) at the second debonding, and 21.9% (nine teeth) at the third debonding, referred in each case to the exposed enamel surface after shearing off the bracket. The damage increasingly involved deeper regions within the enamel. The mean bonding force was 13.2 MPa at the first debonding, 16.1 MPa at the second debonding, and 15.5 MPa at the third. The differences are statistically significant (p < or = 0.05). It would appear that the increase in bonding force between the first and second bracket removal was due to a more pronounced adhesive matrix at the second bonding. The decrease in bonding force at the third debonding may be due to a structure of the enamel caused by the repeated debonding process.(ABSTRACT TRUNCATED AT 250 WORDS)

[Enamel damage depending on the method of bracket removal]. / Uber die Schmelzchädigung in Abhängigkeit von der Methode der Bracketentfernung.

Two different methods of removing brackets, on the one side by torsion and on the other by bending, were compared for the purpose of analyzing the respective enamel lesions. Each test group consisted of 19 extracted human molars with metal brackets attached to the molars by means of the "concise etching technique". Bracket removal was standardized through the use of a Wolpert "Universalprüfmaschine TZZ 707" with modified torsion and bending mechanism. A scanning electron microscope was used to analyze the enamel surface. When using the torsion method, the mean extension of the enamel lesions was 48.3% of the adhesive free enamel surface. These lesions often reached into the deeper enamel layers and were mainly to be found on the broad side of the bonded area. On the other hand, when using the bending method, the enamel lesions were less frequent. They were mainly superficial and were confined almost exclusively to the pressure zones. The stress required to remove the brackets and the stress distribution were calculated on mechanical models and these results corresponded well with the enamel lesions observed on the molars. It can thus be concluded that the method of removing brackets is clinically relevant in relation to enamel lesions.

[Increasing the adhesion of glass ionomer cements in bracket bonding]. / Uber die Erhöhung der Haftung von Glasionomerzementen beim Kleben von Brackets.

For attaching orthodontic brackets glass ionomer cements are being discussed as an alternative material to synthetic glues since they are less aggressive toward the tooth enamel. A serious disadvantage consists in a lower degree of adhesion to enamel. The adhesion can, however, be increased to some extent by enamel preparation. In order to investigate further improvement in this area, 250 freshly extracted bovine teeth were treated with 22 chemicals and their enamel-conditioning properties were tested. For the attachment of the brackets the glass ionomer cements AqaCem and Ketac-cem are used. Tensile shear tests were carried out with a Wolpert universal testing machine. Best results were obtained with the aromatic carbonacids benzoic acid and salicylic acid in acetonic solution. The mean adhesive power was 9.8 MPa. This means an increase of 38% as compared to other pre-conditioning materials such as polyacrylic acid. It can be assumed, that aromatic carbonacids as small, very reactive molecules can establish a closer contact to the phosphate groups of enamel than can the macromolecular polyacrylic acid. Thus, a further step on the way to using glass ionomer cements as a bracket bonding material seems to have been taken.

[The stereognathograph PC--test results with the new version of the device]. / Der Stereognathograph PC--Testergebnisse der neuen Geräteversion.

The PC stereognathograph was investigated for measurement errors in laboratory experiments on an optical bench as well as on an articulator. The values obtained were compared with the data of the predecessor model. A substantial reduction in the linearity in transverse measurements has been effected, so that these are now within acceptable limits. A variation of linearity factors which can be avoided by electronic fine adjustment still arises owing to incongruence of the six measurement channels. The hinge axis can be localized very well on the articulator. By and large, the announced correction of the projection error which we have demanded has not been implemented up to now. In view of the clear imaging of condylar movement in space and time on the monitor and the adequate precision of the clinical measurements effected, the PC stereognathograph appears to be a valuable system for instrumental diagnostics.

[The effect of the interocclusal space on temporomandibular recordings. A study with the use of the Stereognathograph PC]. / Uber den Einfluss des Interokklusalabstandes auf das Kiefergelenkregistrat. Eine Studie unter Verwendung des Stereognathographen PC.

1536 recordings of the condylar movement of 32 patients were made by means of the Stereognathograph PC. The test persons performed mediotrusive and protrusive movements. These movements were recorded with tooth contact and with increased interocclusal space, with and without the clinician's supportive guidance. The objective of the study was to analyse the effects of increased interocclusal space on the recording of the condylar path. Statistical evaluation showed that neither procedure has any real advantage over the other. Both, the occlusal tray as well as the paraocclusal tray may, depending on clinical situation of the ligaments, lead to erroneous recordings. The reproducibility of the recording of the condylar path is only slightly decreased by increased interocclusal space. Considering, however, the amount of work involved in each procedure, the occlusally fixated tray should probably be given preference, when there is no intention of recording occlusal guided movements.

[The accuracy of soft tissue profile prediction with the "Dentofacial Planner" in skeletal prognathism]. / Die Genauigkeit der Weichteilprofil-Vorhersage mit dem "Dentofacial Planner" bei skelettaler Progenie.

30 pre- and postoperative lateral cephalograms of patients with mandibular prognathism are used to evaluate the soft tissue profile prognosis given by the "dentofacial planner". As a result, the horizontal displacement of SLS (sulcus labrale superius) and Pg' (soft tissue pogion) in patients with a normal vertical dimension and additional LMF (labiomental fold) in persons with a marked overbite are calculated well. The horizontal changes of the other points analyzed as well as all vertical changes are not predicted satisfactorily in the momentary version 4.22 A (febr. 1989), which will be improved by the company.

Castillo-Morales' orofacial therapy: treatment of 67 children with Down syndrome.

Infants with Down syndrome often present with a typical orofacial disorder, the features of which include hypotonicity of the perioral muscles, lips and chewing muscles, and a protruding tongue, later followed by active tongue protrusion, as well as problems with sucking, drooling, etc. This study presents the effects of Castillo-Morales' therapy with 67 Down syndrome children (average age at start of therapy 13.9 months), who wore the palatal plate intermittently for an average of 12.1 months. Significant positive results were obtained in spontaneous tongue position, upper and lower lip tonicity and position, mouth closure, drooling and sucking.

[Effect of different enamel structures on bonding of glass ionomer cements]. / Schmelzhaftung von Glasionomerzementen bei unterschiedlichem Schmelzaufbau.

In the present study, the adhesive strength of glass-ionomer cement (GIC) for bracket bonding is analysed in relation to the surface characteristics of the enamel. The bonding of brackets to the enamel of impacted teeth as well as erupted teeth of adolescents and adults is determined in shear force experiments. The results of our investigation shows that GIC attaches to adult enamel to a significantly better extent than to the teeth of adolescents. The poorest values were shown in impacted teeth. It is shown with reference to scanning electron micrograms that surface lesions occur especially frequently in use of conventional etching technique on enamel in adults after debonding the bracket. GIC thus appears to be a promising alternative material for bracket fixation which does not damage the enamel, especially in adult orthodontics. In view of the result, its suitability should be checked in clinical studies.

[Fluorine distribution in the enamel in the use of glass ionomer cements as bonding materials]. / Fluorverteilung im Schmelz bei Einsatz von Glasionomerzementen als Befestigungswerkstoff.

The rise in the fluorine content of dental enamel after bonding orthodontic attachments with glass ionomer cement (GIC) was analysed in an in vitro study. Twenty-four freshly extracted caries-free premolars from adolescent patients were available for investigation. The teeth were cleaved longitudinally in the oro-vestibular direction to obtain a test specimen and reference sample. The GIC Aquacem was used as bonding material. The fluorine was measured with an electron beam microprobe (Camebax SX 50) 10, 20, 40 and 80 days after bonding. A rise of fluorine in dental enamel of more than 120% was observed after the bonding procedure. This rise was especially rapid in the first ten days, and a saturation value was reached after 40 days. The depth of penetration into the dental enamel was 20 microns, and the surface spreading was at least 3 mm. An equilibrium state is attained between the 40th and 80th day. A preventive action on caries in the vicinity of attachments bonded with glass ionomer cement is to be expected owing to the accumulation of fluorine in the dental enamel.