Arnim Godt

Precision of an instrumentation-based method of analyzing occlusion and its resulting distribution of forces in the dental arch.

AbstractBackground and Objective:In practice, analysis of occlusion is reduced to depicting it with color-marking foils. Precise analysis that incorporates time resolution and plots the distribution of forces within the occlusion is not possible in the everyday clinical situation with the usual methods. T-Scan® III is a computer-assisted dental occlusion analyzer that depicts occlusion by means of pressure-sensitive foils. The aim of our study was to test the accuracy and reliability of this method.Subjects and Methods:The study population comprised 42 subjects (23 male and 19 female, aged 20–30, median age 26 years). The measurements were performed using the TScan® III from Tekscan Inc., South Boston, MA, USA. Six recordings with two foils were made for each subject and a total of 30 masticatory cycles were registered. Statistical analysis referred to the method’s measurement accuracy and reliability, as well as the influence of changing the foil and repositioning the T-Scan® III during the repeated measurements.Results:The percentage distribution of forces per tooth ranged from 0 to 41%. The mean measurement per tooth was 6.9% of the maximum total force exerted. The measurement error was 1%, the 1.96-fold measurement error calculated according to Bland & Altman (accuracy) was 2% and the 2.77-fold measurement error (reliability) was 2.8%. Neither changing the foil nor the repeated measuring had any statistically significant influences on the measured value.Conclusion:The measuring technique studied is superior to the usual methods, particularly with regard to force analysis per tooth. The level of accuracy is acceptable and no interference arising from change of foil or repeated measuring was detected. The method presented in this study therefore enhances routine diagnostics with marking foils. A combination of this method with marking foils would be ideal because the pressure-sensitive foils in this system do not produce any contact markings intraorally. This combination enables the contacts depicted on the computer to be assigned intraorally with even greater precision.ZusammenfassungHintergrund und Ziel:Die Analyse der Okklusion ist in der Praxis auf die Abbildung mit farbig markierenden Folien reduziert. Eine präzise zeitlich auflösende und die aufbauende Kraftverteilung darstellende Analyse ist mit den üblichen Methoden im klinischen Alltag nicht möglich. Ein Messverfahren, das computerunterstützt mit drucksensitiven Folien die Okklusion abbildet, ist das T-Scan®-III. Ziel unserer Untersuchung war es, Messgenauigkeit und Reliabilität dieser Methode zu prüfen.Probanden und Methodik:Die Studienpopulation bildeten 42 Probanden (23 männlich und 19 weiblich, 20–30 Jahre alt, Median 26 Jahre). Die Messungen wurden mit dem TScan® III der Firma Tekscan Inc., South Boston, MA, USA, durchgeführt. Bei jedem Probanden wurden insgesamt sechs Messaufzeichnungen mit zwei Folien und insgesamt 30 Kauzyklen aufgezeichnet. Die statistische Auswertung analysierte die Messgenauigkeit und Reliabilität der Methode sowie den Einfluss des Folienwechsels und der Repositionierung des T-Scan®-III während der Wiederholungsmessungen.Ergebnisse:Die prozentuale Kraftverteilung pro Zahn variierte von 0 bis 41%. Der mittlere Messwert pro Zahn betrug 6,9% der maximal entwickelten Gesamtkraft. Der Messfehler betrug 1%, der nach Bland & Altman berechnete 1,96fache Messfehler (Messgenauigkeit) betrug 2% und der 2,77fache Messfehler (Reliabilität) betrug 2,8%. Es wurden keine statistisch signifikanten Einflüsse am Messwert durch den Folienwechsel oder die Wiederholungsmessung festgestelltSchlussfolgerung:Das überprüfte Messverfahren ist, insbesondere aufgrund der Kraftanalyse pro Zahn, den üblichen Methoden überlegen. Die Messgenauigkeit ist akzeptabel und störende Einflüsse durch Folienwechsel oder wiederholte Messungen konnten nicht nachgewiesen werden. Das vorgestellte Verfahren stellt daher eine Ergänzung zur Routinediagnostik mit markierenden Folien dar. Ideal ist eine Kombination dieses Verfahrens mit markierenden Folien, da die drucksensitiven Folien des Messsystems keine Markierungen der Kontaktpunkte intraoral erzeugen. Durch eine Kombination sind die im Computer dargestellten Kontakte noch präziser intraoral zuzuordnen.

Perceived Relative Attractiveness of Facial Profiles with Varying Degrees of Skeletal Anomalies

Objective:The objective of this study was to answer the following questions: Are profiles of Class I patients perceived as more attractive than profiles of Class II or Class III patients in Germany today? How pronounced must a skeletal malocclusion be to be perceived as less attractive? Are there differences in perception between dentists and laypersons?Material and Method:For the present study we examined seven patients with skeletal Class I, orthognathic maxillae and mandibles, and straight average faces (ideal biometric face as defined by A. M. Schwarz). Using the Onyx Ceph™ software, their profile lines were modified to reflect three different Class II profile variants and three different Class III profile variants. The 49 profiles thus obtained were assigned to two groups. Group 1 comprised the seven straight average faces and the first part of the retrognathic and prognathic profile variants. Group 2 comprised the same seven straight average faces and the remaining retrognathic and prognathic profile variants. Both groups of faces were scored by 130 laypersons and 126 dentists.Results:Both groups of observers perceived the seven straight average faces similarly both in the first and second (subsequent) scoring rounds. The straight average face was perceived as most attractive by laypersons (mean, 5.48; 95% confidence interval (CI:) 5.33–5.60) and dentists (mean, 5.44; 95% CI, 5.28–5.50) alike, followed by the mildest variant of the retrognathic face (laypersons, mean, 4.85; 95% CI, 4.68–5.01; dentists, mean, 4.98; 95% CI, 4.81–5.10). Dentists differentiated more clearly by degree of skeletal malocclusion than did laypersons. Both groups alike perceived the extreme variant of the prognathic and retrognathic profile lines as the least attractive. Grouping the subjects by gender yielded only minor differences in perception.Conclusion:The straight average face is perceived as most attractive by representative German populations today. Dentists make clearer gradual distinctions in their perceptions than do laypersons.ZusammenfassungFragestellung:Ziel dieser Studie war die Beantwortung folgender Fragestellungen: Werden heutzutage in Deutschland Profilansichten von Klasse-I-Patienten als attraktiver bewertet als Klasse-II- und Klasse-III-Patienten? Ab welcher skelettalen Anomalieausprägung wird ein Profil als weniger attraktiv empfunden? Gibt es Unterschiede in der Beurteilung zwischen Zahnmedizinern und Laien?Material und Methode:Sieben skelettale Klasse-I-Patienten mit orthognathem Oberkiefer sowie Unterkiefer und Biometgesicht (gerades Mittelwertgesicht nach A. M. Schwarz) wurden mit Hilfe des Computerprogramms Onyx Ceph™ in jeweils drei Klasse-II- und drei Klasse-III-Profilvarianten mit unterschiedlich starker Ausprägung verwandelt. Die so entstandenen 49 Profile wurden in zwei Gruppen aufgeteilt. Die erste Gruppe umfasste die sieben Biometgesichter und den ersten Teil der retrognathen und prognathen Profilverläufe. Die zweite Gruppe bestand ebenfalls aus den gleichen sieben Biometgesichtern sowie den restlichen prognathen und retrognathen Formen. Beide Gesichtsgruppen wurden von 130 Laien und 126 Zahnmedizinern beurteilt.Ergebnisse:Beide Beurteilergruppen beurteilten die sieben Biometgesichter in der ersten und der später folgenden zweiten Bewertung ähnlich. Das Biometgesicht wurde von den Laien (MW: 5,48, 95% Vertrauensintervall (VI) 5,33–5,60) sowie von den Zahnmedizinern (ZM) (MW: 5,44, 95% VI 5,28–5,50) als am attraktivsten beurteilt, direkt gefolgt von der leichtesten Ausprägung des nach hinten schiefen Profilverlaufs (Laien: MW: 4,85, 95% VI 4,68–5,01; ZM: MW: 4,98, 95% VI 4,81–5,10). Die Zahnmediziner stuften deutlicher nach Schweregrad der Abweichung ab als die Laien. Übereinstimmend bewerteten beide Gruppen die extreme Ausprägung des nach vorne und hinten schiefen Profilverlaufs als am unattraktivsten. Die Unterteilung der Probanden in Männer und Frauen ergab nur geringe Unterschiede in der Beurteilung.Schlussfolgerung:Das Biometgesicht wird heutzutage in Deutschland von repräsentativen Populationen als am attraktivsten beurteilt. Zahnmediziner beurteilen mit deutlicheren graduellen Unterschieden als Laien.

Changes in upper airway width associated with Class II treatments (headgear vs activator) and different growth patterns

OBJECTIVE To investigate the upper airways for anteroposterior width against different growth patterns and for alterations during various Class II treatments. MATERIALS AND METHODS Cephalograms from three treatment groups (headgear, activator, and bite-jumping appliance) were evaluated by a single investigator at baseline and at the end of orthodontic treatment. Cephalograms were used to determine upper airway width at different levels in the anteroposterior plane. Patients in the headgear group were additionally divided into six subsets on the basis of y-axis values to assess the influence of different growth patterns. RESULTS Small increases in pharyngeal width were noted at all vertical level segments, both at baseline and during orthodontic treatments. No significant differences in these small increases were noted across various treatment modalities and growth patterns. CONCLUSION Upper airway changes did not significantly vary with the different treatment modalities investigated in the present study. Nevertheless, reductions in pharyngeal width potentially triggering or exacerbating obstructive sleep apnea syndrome (OSAS) are always possible in the headgear phase.

Early Treatment to Correct Class III Relations with or without Face Masks

OBJECTIVE To determine what therapeutic effects can be expected in the case of early treatment of Class III relations with removable appliances with or without face masks. MATERIALS AND METHODS Records available at the university clinic of Tübingen for 41 patients who had undergone early treatment because of prognathic abnormalities were retrospectively evaluated. Lateral cephalograms taken and casts obtained at baseline and at the end of early treatment were included in the analysis. Two treatment strategies were compared. The first group included removable functional orthopedic appliances only (FOA group), while the second group was treated with removable appliances and with face masks mounted on a cemented maxillary expansion appliance (face mask group). RESULTS Positive changes were achieved in both groups for overjet (FOA group: +1.3 mm; face mask group: +2.2 mm) and Wits values (FOA group: +0.4 mm; face mask group: 1.7 mm). Moreover, a change in mean ANB values was achieved in the face mask group (+0.9 degrees ). The FOA group exhibited a reduction in mandibular angles. Changes in maxillary inclination with reduced inclination angles led to increases in overjet and overbite. The face mask group showed dorsal rotation of the mandible with reduced SNB values (-0.8 degrees ). CONCLUSION Early treatment of prognathism is a meaningful option, as demonstrated by the dentoskeletal (and hence functional) improvements observed in the present study.

Pathological changes in the TMJ and the length of the ramus in patients with confirmed juvenile idiopathic arthritis

INTRODUCTION Juvenile idiopathic arthritis (JIA) is characterized by a progressive destruction of the joints. The temporomandibular joints (TMJ) are especially likely to be affected. The often undetected arthritis in the TMJ in particular can cause significant destruction and craniofacial developmental abnormalities. The aim of this study was to analyze the destructive impact of JIA on TMJ and mandibular development. MATERIAL AND METHODS We analyzed a total of 92 joints and mandibular rami using digital cone-beam tomography (CBT) and compared 23 consecutively treated JIA patients with 23 healthy controls, matched for age and gender. We evaluated ramus length, vertical depth of the articular fossa, anterior-posterior dimensions of the mandibular head and condylar process. The statistical analysis was performed using non-parametric Wilcoxon and Kruskal-Wallis Rank Sum tests. RESULTS The JIA patients exhibited significantly more pronounced asymmetries. However, we were unable to detect significant differences in the metric measuring distances. The different JIA subtypes exerted no statistically significant influence. CONCLUSIONS The possible destruction arising as a result of JIA concerns the TMJ and the length of the mandibular ramus. These craniofacial anomalies demonstrate the central importance of sufficiently early detection and timely treatment in the prevention of such growth disturbances.

Reference values for three-dimensional surface cephalometry in children aged 3-6 years.

OBJECTIVE This prospective cross-sectional study design was performed to define reference values for the facial surfaces of 3-6-year-old boys and girls using three-dimensional surface cephalometry. MATERIAL AND METHODS A total of 2290 standardized three-dimensional facial images from 3 to 6-year-old preschool children were separated by gender and assigned to four age categories. All children were Caucasian and revealed no evidence of dentofacial abnormalities. On each image, 31 cephalometric landmarks were marked, resulting in 35 (19 frontal, six lateral, 10 paired) distances and eight angles. Differences between age groups and genders were calculated and significances detected. RESULTS A base table with reference values was compiled, which indicated that boys showed higher values than age-matched girls and that measured distances increased with age. CONCLUSION The mean values from this study could be compiled as a reference table for three-dimensional facial analysis in Caucasian children aged 3-6 years. Such a reference table could be used in comparative studies with other populations or children with craniofacial malformations.

Effects of extraction treatment on maxillary and mandibular sagittal development in growing patients

This retrospective investigation was designed to assess the effects of extraction treatment on the sagittal dimensions of the maxillary and mandibular skeletal structures of growing patients. The records of 40 patients (17 girls, 23 boys; median age 10 years 11 months) whose orthodontic treatment involved extraction of four premolars were evaluated and compared with a control group of 100 patients (54 girls, 46 boys; median age 10 years 7 months) treated non-extraction. Two lateral cephalograms were obtained of each patient, the first before the extractions, T1, and the second at a later point, T2 (mean difference 59 months). Linear parameters, including S-N, the maxillary/mandibular alveolar process, and maxillary/mandibular base, were measured. The same parameters were determined in the control group at corresponding time points (mean difference 63 months). For analysis, the sagittal dimensions of the alveolar processes and jaw bases were compared with each other. The relationships were also established to a reference line known to be unaffected by extraction treatment (S-N). This procedure was performed for the whole sample and for three subgroups formed according to the Wits appraisal. Statistical analysis was carried out using a Students t-test. Comparisons of the total sample showed differences between the groups, which were statistically significant for the maxillary alveolar process, the mandibular alveolar process, and the mandibular base. They varied however in the different subgroups. Whenever extraction treatment is considered, it should be borne in mind that the effects on the sagittal dimension of different bony structures may vary.

Dislocation of an upper third molar by an ossifying fibroma--case report.

BACKGROUND The occurrence of ossifying fibromas (OFs) in childhood and adolescence has been described in the literature, along with different courses of the disease due to different growth rates. CASE REPORT In the case of the 15-year-old female patient presented here, an OF resulted in displacement of a maxillary third molar far into the maxillary sinus. It is assumed that the tumour originated coronal to the affected tooth 18. Radiographs document an initial rapid growth of this tumour over a period of 2 years, while its growth almost completely ceased in the next 2 years immediately prior to diagnosis and surgical treatment. The operation was complicated by unexpected profuse bleeding from the tumour tissue. CONCLUSION The peculiarity of the OF in the case presented here is its similarity, in terms of clinical and radiological appearances, with a follicular cyst, its unusual place of origin that resulted in the migration of the tooth 18 into the maxillary sinus, its different growth dynamics, and the pronounced haemorrhage encountered as the tumour was surgically removed.

Cervical Headgear Treatment and Growth Patterns: Analysis by Lateral Cephalometry

Objective:Retrospective cephalometric study of changes in vertical and sagittal relations after headgear treatment depending on preexisting growth patterns.Materials and Methods:Lateral cephalograms obtained from 119 patients before and after headgear treatment were analyzed. All patients were treated with headgears exclusively. Only cases were included that showed bilateral improvement of least 4 mm in Class II occlusion after headgear treatment lasting at least 6 months. Patients were assigned to six groups based on y-axis values obtained at baseline.Results:Almost all groups revealed substantial improvements in skeletal Class II relations, including 1.38°–1.72° reductions in ANB angles and 0.62–0.81 mm reductions in Wits values. SNA values fell by 0.51–1.25°. SNB angle values increased by 0.21°– 0.95°. SN-MeGo angles and mandibular angles were reduced, while y-axis values remained essentially unchanged during headgear treatment. Different results were only obtained in the group with the most pronounced horizontal growth pattern. Those patients revealed lower SNB angle values (–0.93°) and increased vertical relations (y-axis: +1.39°; SN-MeGo angle: +1.22°; mandibular angle: +0.01°) after headgear treatment. All groups showed a reduction in basal plane angles and maxillary retroinclination after treatment.Conclusion:Our results do not support the conventional recommendation that cervical headgears should not be used in the presence of vertical growth patterns.ZusammenfassungZiel:Retrospektive fernröntgenkephalometrische Untersuchung der Veränderungen vertikaler und sagittaler Beziehungen nach Headgearbehandlung in Abhängigkeit vom Wachstumsmuster zu Behandlungsbeginn.Material und Methodik:Die Fernröntgenseitenbilder zu Beginn und nach Beendigung einer ausschließlichen Headgearbehandlung von 119 Patienten wurden ausgewertet. Einschlusskriterien waren eine Verbesserung der Distalokklusion um mindestens 1/2 Pb beidseits und eine mindestens 6-monatige Behandlungsdauer. Anhand der y-Achse zu Behandlungsbeginn erfolgte die Einteilung der Patienten in sechs Gruppen.Ergebnisse:In fast allen Gruppen zeigte sich eine deutliche Verbesserung der skelettalen Klasse II (Veränderung des ANB-Winkels zwischen –1,38° und –1,72°, Veränderung des Wits-Wertes zwischen –0,62 mm und –0,81 mm), eine Reduktion des SNA-Wertes (zwischen –0,51° und –1,25°) und eine Vergrößerung des SNB-Wertes (zwischen 0,21° und 0,95°). Darüber hinaus kam es zu einer Verkleinerung des SN-MeGo- und des Kieferwinkels, während der Wert für die y-Achse weitgehend stabil blieb. Eine Ausnahme bildete die Gruppe mit ausgeprägt horizontalem Wachstumsmuster, in der sich eine Verkleinerung des SNB-Wertes (–0,93°) und eine Vergrößerung der vertikalen Relationen (y- Achse +1,39°, SN-MeGo +1,22°, Kieferwinkel +0,01°) zeigte. In allen Gruppen kam es zu einer Reduktion des Basiswinkels und zu einer Veränderung der Oberkieferinklination im Sinne einer Retroinklination.Schlussfolgerung:Anhand dieser Ergebnisse kann die übliche Empfehlung zum Verzicht des zervikalen Headgears bei vertikalem Wachstumsmuster nicht unterstützt werden.

Treating Class II Patients with Removable Plates and Functional Orthopedic Appliances@@@Die Behandlung von Klasse-II-Patienten mit abnehmbaren Platten und funktionskieferorthopädischen Geräten: The Importance of Anterior Tooth Inclination and Direction of Growth on Treatment Outcome@@@Bedeutung der Frontzahninklination und Wachstumsrichtung für das Behandlungsergebnis

Objective:To determine the influence of physiological growth pattern and anterior tooth inclination on the outcome in Class II patients treated with removable orthodontic plates and functional orthodontic appliances.Patients and Methods:After recruiting 50 patients with an upper anterior proclination of 1-SN ≥ 107° for this retrospective study, another 50 patients with a retroclination of 1-SN ≤ 95° were also included. All patients initially presented a skeletal Class II relationship with a distoclusion of at least one premolar width in the region of the first molars. All patients were evaluated separately by gender and additionally subdivided into three subgroups with a horizontal, neutral, or vertical craniofacial configuration. Treatment with removable orthodontic plates (pretreatment) and functional orthodontic appliances was initiated in mixed dentition. Pre- and post-treatment lateral cephalograms were evaluated for each patient.Results:Dento-alveolar analysis showed that the inclination of the upper incisors changed in the direction of the clinical standard value independent of the craniofacial configuration, although full correction using removable orthodontic plates and functional orthodontic appliances was not always achieved. Similarly good treatment outcomes were achieved with regard to overjet and overbite. The lower incisors of all patients were in proclination after treatment.The ANB angle was reduced in both groups. Nevertheless, on average a skeletal Class II persisted in the Class II, Division 2 patients, while Class II, Division 1 patients with horizontal craniofacial configurations attained skeletal Class I.Conclusions:Treatment of Class II patients with removable appliances resulted in differences depending on anterior tooth inclination (Class II, Division 1 and II, Division 2) and craniofacial configuration. These differences must be taken into account during treatment planning. Complete treatment success with regard to sagittal jaw balance is very difficult to achieve with removable orthodontic plates (pre-treatment) and functional orthodontic appliances alone in Class II, Division 1 cases with a vertical craniofacial configuration and generally in Class II, Division 2 cases. A particularly favorable constellation for removable treatment is a Class II, Division 1 situation with a horizontal craniofacial configuration and retroclined or orthognathic mandibular anteriors.ZusammenfassungFragestellung:Wie wirken sich das physiologische Wachstumsmuster und die Frontzahninklination bei der Therapie mit abnehmbaren Platten und funktionskieferorthopädischen Geräten auf das Behandlungsergebnis der Klasse II aus?Patienten und Methodik:Nachdem für diese retrospektive Studie 50 Klasse-II/1-Patienten mit Proklination (1-SN ≥ 107°) rekrutiert waren, wurden weitere 50 Klasse-II/2-Patienten mit Reklination der Oberkieferfront (1-SN ≤ 95°) ausgewählt, die alle eine skelettale Klasse II mit einem Distalbiss von mindestens einer Prämolarenbreite im Bereich der 6-Jahr-Molaren aufwiesen. Alle Patienten wurden getrennt nach Geschlecht bewertet und zusätzlich in Gruppen mit horizontalem, neutralem und vertikalem Schädelaufbau unterteilt. Der Behandlungsbeginn der Therapie mit abnehmbaren Platten (Vorbehandlung) und funktionskieferorthopädischen Geräten fand im Wechselgebiss statt. Von jedem Patienten wurden ein prä- und posttherapeutisches Fernröntgenseitenbild ausgewertet.Ergebnisse:Die dentoalveoläre Analyse ergab, dass sich die Inklination der oberen Inzisivi unabhängig von der Wachstumsrichtung in allen Gruppen hin zu Normwerten veränderte, mit abnehmbaren Platten und funktionskieferorthopädischen Geräten aber nicht immer vollständig korrigieren ließ. Hinsichtlich des Overjets und Overbites wurden ähnlich gute Behandlungsergebnisse erzielt. Die unteren Inzisivi waren bei allen Patienten nach der Therapie prokliniert.In beiden Gruppen reduzierte sich der ANB-Winkel. Trotzdem blieb bei den Klasse-II/2-Patienten die skelettale Klasse II im Durchschnitt bestehen. Die Klasse-II/1-Patienten mit horizontalem Schädelaufbau hingegen erreichten eine skelettale Klasse I.Schlussfolgerungen:Bei der Behandlung der Klasse II mit herausnehmbaren Apparaturen ergaben sich Unterschiede in der Abhängigkeit von der Frontzahninklination (Klasse II/1 und II/2) und der Wachstumsrichtung. Diese Unterschiede sind bei der Planung zu berücksichtigen. Allein mit abnehmbaren Platten (Vorbehandlung) und funktionskieferorthopädischen Geräten ist bei Klasse-II/1-Fällen mit vertikalem Wachstumsmuster und generell bei Klasse-II/2-Patienten bezüglich des sagittalen Kieferlageausgleichs ein vollständiger Therapieerfolg problematisch. Eine besonders günstige Konstellation für herausnehmbare Geräte besteht bei der Klasse II/1 mit horizontalem Schädelaufbau und rekliniert oder orthognath stehenden Unterkieferfrontzähnen.