Franka Stahl

Light-emitting diode (LED) polymerisation of dental composites : Flexural properties and polymerisation potential

The clinical performance of light polymerised dental composites is greatly influenced by the quality of the light-curing unit (LCU) used. Commonly used halogen LCUs have some specific drawbacks such as decreasing of the light output with time. This may result in low degree of monomer conversion of the composites with negative clinical implications. Previous studies have shown that blue-light-emitting diode (LED) LCUs have the potential to polymerise dental composites without having the drawbacks of halogen LCUs. Despite the relatively low irradiance of current LED LCUs, their efficiency is close to that of conventional halogen LCUs with more than twice the irradiance. This phenomenon has not been explained fully yet. Hence, more tests of the LED LCUs effectiveness and of the mechanical properties of oral biomaterials processed with LED LCUs need to be carried out. This study investigates the flexural properties of three different composites with three different shades, which were polymerised with either a commercial halogen LCU or an LED LCU, respectively. In most cases no significant differences in flexural strength and modulus between composites polymerised with a halogen LCU or an LED LCU, respectively, were found. A simple model for the curing effectiveness based on the convolution absorption spectrum of the camphorquinone photoinitiator present in composites and the emission spectra of the LCUs is presented.

Longitudinal growth changes in untreated subjects with Class II Division 1 malocclusion

INTRODUCTION The purpose of this longitudinal study was to compare the craniofacial growth changes in untreated subjects with Class II Division 1 malocclusion with those in subjects with normal (Class I) occlusion from the prepubertal through the postpubertal stages of development, as defined by a biological indicator of individual skeletal maturity (cervical vertebral maturation method). METHODS The Class II Division 1 sample consisted of 17 subjects (11 boys, 6 girls). The Class I sample also consisted of 17 subjects (13 boys, 4 girls). The lateral cephalograms of the subjects in both groups were analyzed at 6 consecutive stages of development, from CS1 through CS6. The statistical comparisons of the growth changes in the study groups were performed with Mann-Whitney U tests. RESULTS Craniofacial growth in subjects with untreated Class II malocclusion is essentially similar to that in untreated subjects with normal occlusion at all developmental intervals, with the exception of significantly smaller increases in mandibular length (P <0.001) at the growth spurt (interval CS3-CS4) and during the overall observation period (intervals CS1-CS6). CONCLUSIONS Class II dentoskeletal disharmony does not tend to self-correct with growth in association with worsening of the deficiency in total mandibular length and mandibular ramus height.

[Relationship between occlusal findings and orofacial myofunctional status in primary and mixed dentition. Part I: Prevalence of malocclusions].

Aim:The aim of this study is to provide basic data on the prevalence of malocclusions and orofacial dysfunctions in the primary and early mixed dentition, to examine occlusal relationships in their functional context, and to analyze the need for and potential of orthodontic prevention.Subjects and Methods:Occlusal relationships and myofunctional status were evaluated in 766 children in the primary dentition and in 2,275 children in the early mixed dentition. Orthodontic findings in single jaws and intermaxillary occlusal relationships were clinically analyzed in all three dimensions.Results:Normal occlusal relationships were found in 25.3% of children in the primary dentition. Frequency of children with normal dentitions fell significantly in the mixed dentition (7.3%). Prevalence of bilateral distoclusion increased significantly from the primary to the mixed dentition. Increased maxillary overjet was diagnosed in 49.3% and 59.0% of the children in the primary and mixed dentition, respectively. Prevalence of lateral crossbites increased significantly from primary to mixed dentition (7.2% vs. 12.0%). Deep bites and edge-to-edge bites were found significantly more often in the early mixed dentition.Conclusions:The significant increase in the prevalence of malocclusions between the primary and mixed dentition – distoclusion and lateral crossbite, and the impairment of vertical occlusal relationships in the mixed dentition in particular – reveal the need for orthodontic prevention. They highlight the absence of applied interceptive and early treatment measures in orthodontics. The indication system in current use for early orthodontic treatment here in Germany fails to fulfill the requirements for prevention-oriented dental care.ZusammenfassungZiel:Ziel der Studie ist es, repräsentative Basisdaten über die Verbreitung von Gebissanomalien und orofazialen Fehlfunktionen im Milchgebiss und im frühen Wechselgebiss zu liefern und die Okklusionsbeziehungen in ihrem funktionellen Kontext zu überprüfen. Erfordernisse und Möglichkeiten kieferorthopädischer Prävention und Frühbehandlung sollten geprüft werden.Probanden und Methodik:Bei 766 Kindern mit Milchgebissen und 2275 Kindern mit Wechselgebissen wurden die Okklusionsbefunde und der Funktionsstatus erhoben. Die kieferorthopädischen Befunde wurden als sagittale, transversale und vertikale Einzelkiefer- und Okklusionsbefunde klinisch erhoben.Ergebnisse:Im Milchgebiss wiesen 25,3% der Kinder regelrechte Okklusionsbeziehungen auf. Im Wechselgebiss reduzierte sich dieser Anteil statistisch signifikant auf 7,3%. Die Häufigkeit beidseitiger Distalokklusionen nahm vom Milch- zum Wechselgebiss statistisch signifikant zu. Bei 49,3% bzw. 59,0% der Kinder mit Milch- und Wechselgebissen wurde eine vergrößerte sagittale Frontzahnstufe registriert. Vom Milch- zum Wechselgebiss stieg die Häufigkeit der seitlichen Kreuzbisse von 7,2% auf 12,0% statistisch signifikant an. Tiefbisse und Kantenbisse traten im frühen Wechselgebiss statistisch signifikant häufiger auf.Schlussfolgerungen:Die signifikante Zunahme der Gebissanomalien vom Milch- zum Wechselgebiss, insbesondere der Distalokklusion und des seitlichen Kreuzbisses, und die Verschlechterung der vertikalen Okklusionsverhältnisse im Wechselgebiss weisen die Notwendigkeit einer kieferorthopädischen Prävention nach und zeigen den mangelnden Einsatz kieferorthopädischer Interzeptiv- und Frühbehandlungsmaßnahmen. Die gegenwärtig angewandten kieferorthopädischen Indikationsgruppen zur kieferorthopädischen Frühbehandlung erfüllen den Anspruch einer präventionsorientierten Zahnmedizin nicht.

Orthodontic findings in the deciduous and early mixed dentition--inferences for a preventive strategy.

Abstract.Aim and Method:The aim of the present epidemiologic study was to obtain representative basic data on the frequency, extent and age-dependence of malocclusions in the deciduous and early mixed dentition. The developmental tendencies of specific malocclusions were investigated from the aspect of orthodontic prevention. The collective comprised 8,864 preschool and schoolage children, of whom 1,225 were in the deciduous dentition (mean age 4.5 years) and 7,639 in the mixed dentition (mean age 8.9 years). The orthodontic data were clinically assessed as sagittal, transversal, or vertical single-arch and occlusal findings. In addition, the malocclusions were classified according to their primary symptoms. Early infantile habits, tongue dysfunctions, speech defects and incompetent lip closure were registered separately.Results:57% of the children were found to have malocclusions, with the frequency rising statistically significantly in dependence on age from the deciduous to the mixed dentition (p ≤ 0.001). The mean extent of excessive overjet increased significantly from the deciduous to the mixed dentition. Crossbite with mandibular midline discrepancies were observed significantly more frequently in the deciduous dentition. Although the frequency of anterior open bite underwent a significant decline from the deciduous to the mixed dentition, open bite was the malocclusion most frequently associated with dysfunction in both groups. The significant increase in traumatic deep bite in the mixed dentition indicates an unfavorable developmental tendency in this anomaly until after the eruption of the permanent incisors.Conclusion:The need for preventive orthodontic therapy and for the intensified application of interceptive and early treatment measures is stressed in view of the high number of malalignments and malocclusions in the deciduous and mixed dentition and the tendency for some forms of malocclusion to deteriorate as the dentition develops.Zusammenfassung.Ziel und Methodik:Zielstellung der epidemiologischen Studie war es, repräsentative Basisdaten über die Verbreitung, das Ausmaß und die Altersabhängigkeit von Gebissanomalien im Milch- und frühen Wechselgebiss zu liefern. Unter dem Gesichtspunkt der kieferorthopädischen Prävention wurden die Entwicklungstendenzen spezifischer Anomalien untersucht. Das Untersuchungsmaterial umfasste 8864 Kindergarten- und Schulkinder mit 1225 Milch- (durchschnittliches Alter 4,5 Jahre) und 7639 Wechselgebissen (durchschnittliches Alter 8,9 Jahre). Die kieferorthopädischen Daten wurden als sagittale, transversale, vertikale Einzelkiefer- und Okklusionsbefunde klinisch beurteilt. Zusätzlich erfolgte eine Klassifikation der Gebissanomalien nach ihrer Leitsymptomatik [34]. Frühkindliche Habits, Zungenfehlfunktionen, Sprechfehler und inkompetenter Lippenschluss wurden extra erfasst.Ergebnisse:Bei 57% der Kinder wurden Gebissanomalien festgestellt. Vom Milch- zum Wechselgebissalter stieg die Anomaliehäufigkeit statistisch signifikant an (p ≤ 0,001). Die durchschnittliche Größe der vergrößerten sagittalen Schneidekantenstufe nahm vom Milch- zum Wechselgebiss signifikant zu. Kreuzbisse mit Mittellinienabweichungen des Unterkiefers traten im Milchgebiss signifikant häufiger auf. Auch wenn die Häufigkeit des frontal offenen Bisses vom Milch- zum Wechselgebiss signifikant abnahm, war der offene Biss die am häufigsten mit Fehlfunktionen einhergehende Anomalie in beiden Gruppen. Die signifikante Zunahme der traumatisch tiefen Bisse im Wechselgebissalter lassen auf eine ungünstige Entwicklungstendenz dieser Anomalie bis nach dem Schneidezahnwechsel schließen.Schlussfolgerung:Der Forderung nach kieferorthopädischer Prophylaxe und dem verstärkten Einsatz von Interzeptiv- und Frühbehandlungsmaßnahmen ist angesichts der hohen Anzahl von Zahnfehlstellungs- und Bisslageanomalien im Milch- und Wechselgebiss und der Verschlechterungstendenz einiger Dysgnathien im Verlauf der Gebissentwicklung Nachdruck zu verleihen.

Comparison of 2 comprehensive Class II treatment protocols including the bonded Herbst and headgear appliances: a double-blind study of consecutively treated patients at puberty.

INTRODUCTION The aim of this clinical trial was to compare the effects of 2 protocols for single-phase comprehensive treatment of Class II Division 1 malocclusion (bonded Herbst followed by fixed appliances [BH + FA] vs headgear followed by fixed appliances and Class II elastics [HG + FA]) at the pubertal growth spurt. METHODS Fifty-six Class II patients were enrolled in the trial and allocated by personal choice to 2 practices, where they underwent 1 of 2 treatment protocols (28 patients were treated consecutively with BH + FA, and 28 patients were treated consecutively with HG + FA). All patients started treatment at puberty (cervical stage [CS] 3 or CS 4) and completed treatment after puberty (CS 5 or CS 6). Lateral cephalograms were taken before therapy and 6 months after the end of comprehensive therapy, with an average interval of 28 months. Longitudinal observations of a matched group of 28 subjects with untreated Class II malocclusions were compared with the 2 treated groups. Analysis of variance (ANOVA) with post-hoc tests was used for statistical comparisons. Discriminant analysis was applied to identify preferential candidates for the BH + FA protocol on the basis of profile changes (advancement of the soft tissues of the chin). RESULTS The success rate (full occlusal correction of the malocclusion after treatment) was 92.8% in both treatment groups. The BH + FA group showed a significant increase in mandibular protrusion. The increase in effective mandibular length (Co-Gn) was significantly greater in both treatment groups when compared with natural growth changes in the Class II controls. Significantly greater improvement in sagittal maxillomandibular relationships was found in the BH + FA group. Retrusion of maxillary incisors and mesial movement of mandibular molars were significant in the HG + FA group. The BH + FA group showed significantly greater forward movements of soft-tissue B-point and pogonion compared with both the HG + FA and the control groups. Two pretreatment variables were significant (F = 4.48; P <0.01) in predicting the posttreatment amount of mandibular soft-tissue improvement in the BH + FA group: Co-Go-Me and pogonion to nasion perpendicular. CONCLUSIONS Class II treatment with either protocol during the pubertal growth spurt induces significant favorable dentoskeletal and occlusal changes. Functional jaw orthopedics had a greater favorable impact on the advancement of the chin. The clinical indications for the preferential use of the Herbst appliance at puberty are a small mandibular angle and mandibular retrusion before treatment. When treated with the BH + FA protocol, these Class II patients have the greatest probability of achieving significant improvement in the profile by advancement of the soft tissues of the chin.

Dentofacial growth changes in subjects with untreated Class II malocclusion from late puberty through young adulthood

INTRODUCTION The purpose of this longitudinal study was to compare dentofacial growth changes in untreated subjects with Class II Division 1 malocclusion with those in subjects with normal (Class I) occlusion from late puberty through young adulthood. METHODS The Class II Division 1 sample consisted of 23 subjects (10 male, 13 female). The Class I sample included 30 subjects (13 male, 17 female). The lateral cephalograms of the subjects in both groups were analyzed at 2 consecutive stages of development: T1, postpubertal observation (cervical vertebral maturation stage 6), and T2, young adulthood stage. The average time between T1 and T2 was 3.5 years. The statistical comparisons of the growth changes in the 2 groups were performed with Mann-Whitney U tests. RESULTS From late puberty through young adulthood, dentofacial growth in subjects with untreated Class II malocclusion does not show significant differences when compared with that observed in untreated subjects with normal occlusion. CONCLUSIONS These findings show that Class II dentoskeletal disharmony does not exhibit significant growth change from late puberty through young adulthood.

Relationship between occlusal findings and orofacial myofunctional status in primary and mixed dentition. Part II: Prevalence of orofacial dysfunctions.

Aim:The aim of this study was to provide basic data on the prevalence of orofacial dysfunctions in primary and early mixed dentition and to examine occlusal relationships in their functional context, and to analyze the need for and potential of orthodontic prevention and early treatment.Subjects and Methods:We assessed the occlusal relationships and myofunctional status of 3,041 children. The presence of dynamic and static myofunctional disorders and any oral habits were documented during functional analysis.Results:The frequency of myofunctional disorders was statistically significantly higher in children with increased maxillary overjet, frontal open bite, lateral crossbite and mandibular prognathism, and there was a statistically significant increase in the prevalence of orofacial dysfunctions and oral habits from primary to mixed dentitions.Conclusions:Habitual open mouth posture (expressing hypotonia in the perioral muscles) and a visceral swallowing pattern become established during the primary dentition and are increasingly carried over into the mixed dentition period. Both criteria, along with assessment of occlusal relationships, are appropriate parameters with which to identify “children at risk for orthodontic treatment”.ZusammenfassungZiel:Ziel der Studie ist es, Basisdaten über die Verbreitung von orofazialen Dysfunktionen im Milch- und frühen Wechselgebiss bereitzustellen und die Okklusionsbeziehungen in ihrem funktionellen Kontext zu untersuchen. Es sollen Erfordernisse und Möglichkeiten kieferorthopädischer Prävention und Frühbehandlung geprüft werden.Probanden und Methodik:Bei 3041 Kindern wurden Okklusionsbefund und myofunktioneller Status erhoben. Dynamische und statische myofunktionelle Störungen sowie bestehende Habits wurden während der funktionellen Untersuchung diagnostiziert.Ergebnisse:Myofunktionelle Störungen wurden statistisch signifikant häufiger bei Kindern mit vergrößerter sagittaler Schneidekantenstufe, frontal offenem Biss, seitlichem Kreuzbiss und Progenie gefunden. Vom Milch- zum Wechselgebiss steigt die Häufigkeit orofazialer Dysfunktionen und Habits statistisch signifikant an.Schlussfolgerungen:Die offene Mundhaltung als Haltungsschwäche und das viszerale Schluckmuster etablieren sich im Milchgebiss und werden zunehmend auf das Wechselgebiss übertragen. Beide Kriterien eignen sich zusammen mit der Erhebung des Okklusionsbefundes für die Definition „kieferorthopädisches Risikokind“.

Thin-plate spline analysis of craniofacial growth in Class I and Class II subjects.

OBJECTIVE To compare the craniofacial growth characteristics of untreated subjects with Class II division 1 malocclusion with those of subjects with normal (Class I) occlusion from the prepubertal through the postpubertal stages of development. MATERIALS AND METHODS The Class II division 1 sample consisted of 17 subjects (11 boys and six girls). The Class I sample also consisted of 17 subjects (13 boys and four girls). Three craniofacial regions (cranial base, maxilla, and mandible) were analyzed on the lateral cephalograms of the subjects in both groups by means of thin-plate spline analysis at T1 (prepubertal) and T2 (postpubertal). Both cross-sectional and longitudinal comparisons were performed on both size and shape differences between the two groups. RESULTS The results showed an increased cranial base angulation as a morphological feature of Class II malocclusion at the prepubertal developmental phase. Maxillary changes in either shape or size were not significant. Subjects with Class II malocclusion exhibited a significant deficiency in the size of the mandible at the completion of active craniofacial growth as compared with Class I subjects. CONCLUSION A significant deficiency in the size of the mandible became apparent in Class II subjects during the circumpubertal period and it was still present at the completion of active craniofacial growth.

Epidemiology of Hoffmeister's “Genetically Determined Predisposition to Disturbed Development of the Dentition” in Patients With Cleft Lip and Palate

Objective Type and prevalence rates of the symptoms of Hoffmeisters “genetically determined predisposition to disturbed development of the dentition” were studied in patients with clefts. Patients Data of 263 patients with nonsyndromic clefts of lip (alveolus and palate) or isolated cleft palates were examined in a retrospective study. Setting The clefts were classified as cleft lip or cleft lip and alveolus, cleft palate, unilateral cleft lip and palate, and bilateral cleft lip and palate. All patients were scrutinized for 28 individual symptoms. Prevalences of the individual symptoms were statistically evaluated regarding cleft type and gender by using the chi-square test and were also compared with findings in patients without clefts. Results In 97.7% of the patients with clefts, at least one symptom was found. Microdontia of individual teeth, hypodontia, and hyperodontia were the symptoms most frequently recorded. Comparison of the different cleft types revealed differences regarding the prevalences of supernumerary lateral incisors (p = .051), infraposition of deciduous molars (p < .001), and atypical tooth bud position (p = .030). Comparison of the prevalences of 10 symptoms recorded in the patients with clefts with the prevalences recorded in patients without clefts showed nine symptoms were found much more frequently in the population with clefts. Conclusion These findings support the hypothesis that clefting is part of a complex malformation associated with other dental anomalies resulting from disturbed development of the dentition. Patients with clefts are also likely to present other deficiencies of dental development and tooth eruption in both dentitions, even in regions not affected by the cleft.

Interrelation between occlusal findings and orofacial myofunctional status in primary and mixed dentition: Part III: Interrelation between malocclusions and orofacial dysfunctions.

Aim:It was the purpose of this study to analyze the relationship between selected types of malocclusion and specific types of static and dynamic orofacial dysfunction and to compare the results with subjects presenting regular occlusion. We aimed to identify which orthodontic and functional symptoms in early dentition would lead to malocclusion later on.Subjects and Methods:Occlusal relations and myofunctional status were evaluated in 3,041 children. We diagnosed dynamic and static myofunctional disorders as well as oral habits by means of functional examinations.Results:No orofacial dysfunctions were found in 11.2% of the children with primary dentition and in 10.2% of the children with early mixed dentition. We observed no correlation between the existence of distoclusion and functional disorders. Lateral crossbite in mixed dentition, as well as increased overjet and frontal open bite in primary and early mixed dentitions appeared significantly more frequently in children with orofacial dysfunctions. Individuals with frontal open bite, lateral crossbite, reduced and increased overjet presented static dysfunctions significantly more frequently than those in dentitions with normal occlusion. Dynamic dysfunctions were significantly more prevalent in subjects with frontal open bite and lateral crossbite than in those with normal occlusion.Conclusions:Our results enable us to prognosticate which children risk future orthodontic problems. Any child presenting one of the four occlusal disorders plus one static or two dynamic dysfunctions is a child more likely to develop orthodontic problems later on. Orthodontic prevention and early treatment must include functional rehabilitation so as to eliminate or at least diminish those factors causing undesirable developments.ZusammenfassungZiel:Ausgewählte Gebissanomalien sollen auf ihren Zusammenhang mit spezifischen statischen und dynamischen orofazialen Dysfunktionen untersucht und mit Probanden ohne Gebissanomalie verglichen werden. Prognostische Aussagen, bei welcher kieferorthopädischen und funktionellen Symptomatik mit einer risikobehafteten Gebissentwicklung zu rechnen ist, sollen abgeleitet werden.Probanden und Methodik:Bei 3041 Kindern wurden Okklusionsbefund und myofunktioneller Status erhoben. Dynamische und statische myofunktionelle Störungen sowie bestehende Habits wurden während der funktionellen Untersuchung diagnostiziert.Ergebnisse:Nur bei 11,2% und 10,2% der Kinder im Milch- und frühen Wechselgebiss mit Gebissanomalien wurden keine orofazialen Dysfunktionen nachgewiesen. Die Distalokklusion zeigte sich durch Funktionsstörungen nicht differenziert. Seitliche Kreuzbisse im Wechselgebiss sowie vergrößerte Frontzahnstufen und frontal offene Bisse im Milch- und frühen Wechselgebiss wurden signifikant häufiger bei Kindern mit orofazialen Dysfunktionen festgestellt. Statische Dysfunktionen traten beim frontal offenen Biss, seitlichen Kreuzbiss und bei reduzierten und vergrößerten sagittalen Frontzahnstufen signifikant häufiger auf als bei regelrechten Okklusionsverhältnissen. Dynamische Dysfunktionen lagen beim frontal offenen Biss und beim seitlichen Kreuzbiss signifikant häufiger vor als bei regelrechter Okklusion.Schlussfolgerungen:Die Ergebnisse lassen die Definition einer risikobehafteten Prognose zu. Das „kieferorthopädische Risikokind“ wird definiert, wenn bei einer der vier Okklusionsstörungen zusätzlich eine statische Funktionsstörung oder zwei dynamische Funktionsstörungen bestehen. Die Konzepte der kieferorthopädischen Prävention und Frühbehandlung müssen die funktionelle Rehabilitation zur Ausschaltung oder Reduzierung der Ursachen der Fehlentwicklung beinhalten.