Assessment of two e-learning methods teaching undergraduate students cephalometry in orthodontics.

AIM: Cephalometry is important for orthodontic diagnosis and treatment planning and is part of the core curriculum for training dentists. Training involves identifying anatomical landmarks. The aim of this investigation was to assess whether e-learning improves learning efficiency; a programme specifically designed for this purpose was compared to commercially available software. METHODS: Thirty undergraduate students underwent traditional training of cephalometry consisting of lectures and tutorials. Tracing skills were tested immediately afterwards (T0). The students were then randomly allocated to three groups: 10 students served as control (CF); they were asked to improve their skills using the material provided so far. Ten students were given a program specifically designed for this study that was based on a power point presentation (PPT). The last group was given a commercially available program that included teaching elements (SW). The groups were tested at the end the six week training (T1). The test consisted of tracing 30 points on two radiographs and a point score improvement was calculated. The students were interviewed after the second test. RESULTS: Both e-learning groups improved more than the traditional group. Improvement scores were four for CF; 8.6 for PPT and 2.8 for SW. For PPT all participants improved and the student feedback was the best compared to the other groups. For the other groups some candidates worsened. CONCLUSIONS: Blended learning produced better learning outcomes compared to using a traditional teaching method alone. The easy to use Power Point based custom software produced better results than the commercially available software.

[Normal nasalance for the German language. Nasometric values for clinical use in patients with cleft lip and palate]. / Objektive Messung der Nasalanz in der deutschen Hochlautung. Ein Vergleichskollektiv zur Beurteilung funktioneller Ergebnisse bei Lippen-Kiefer-Gaumen-Spalten.

OBJECTIVE: Rhinophonia is often present in patients with cleft lip and palate (CLP) many years after palatoplasty. It may be caused either by organic deficits, functional disorders, or both. NasalView is known as an instrument for the objective assessment of nasalance in cases of velopharyngeal insufficiency or incompetence.However,normative values for the German language are not yet available. In order to overcome this problem, this study evaluated such norms using NasalView. METHODS: A total of 50 individuals with normal speech development were examined with NasalView. The median age was 14 years (range 11-20 years). The tone material used comprised the vowels /a:/, /e:/, /i:/, /o:/, /u:/, the sentences S(1): "Die Schokolade ist sehr lecker."("This chocolate is very tasty.") and S(2): "Nenne meine Mamma Mimmi."("Call my mummy Mimmi."), and the text passages of LT(1): "Nordwind und Sonne"("Northwind and sun"), LT(2): "Kindergeburtstag"("A child's birthday party") and LT(3): "Der grosse Gesang"("A famous song"). RESULTS: The mean nasalance for the vowels was 35.9% (+/-8.4), for S(1) (containing no nasal consonants) 24.9% (+/-5.3), and for S(2) 69.6% (+/-5.5) (with many nasal sounds). The results for the text passages were 42.1% (+/-4.2) for LT(1), 36.9% (+/-4.3) for LT(2) and 38.2% (+/-4.4) for LT(3). CONCLUSION: The norms of nasalance for the German language presented here may be useful in measuring the long-term outcome of cleft lip and palate.

Different orthodontic treatment effects in Angle Class III patients.

The aim of this study was to compare the different treatment effects observed in Angle Class III patients treated either exclusively in the primary dentition or receiving treatment initiated during the early mixed dentition. 14 patients from five families were enrolled in this retrospective study. The treatment course, appliances, treatment length and treatment outcomes were compared. The skeletal changes were assessed by analyzing cephalometric radiographs taken prior to, during and after completion of orthodontic treatment. In those patients receiving treatment in the primary dentition only, the course of treatment was more continuous and only one appliance had to be used. Moreover, the treatment time was shorter compared to those patients starting treatment in the early mixed dentition (5.4 +/- 2.1 vs 21.1 +/- 9.7 months). Treatment exclusively in the primary dentition showed better dentoalveolar results.

Suggestion for orthodontic and speech improving measures in CLP patients.

The objective of the present paper is to describe a soft palate level device, the veloretractor, which is a combination of orthodontic appliance and therapeutic aid in speech therapy. Its use is demonstrated in a case report of a child with complete bilateral cleft lip and palate. Both orthodontic and phoniatric/pedaudiologic treatment needs during the course are demonstrated along with the treatment results.

Face, palate, and craniofacial morphology in patients with a solitary median maxillary central incisor.

The occurrence of a solitary median maxillary central incisor (SMMCI) is a very rare condition and might be a sign of a mild degree of holoprosencephaly. In this investigation, material from 10 patients, nine girls and one boy with a SMMCI (8-17 years of age) registered in orthodontic clinics was examined. The purpose was to evaluate the clinical characteristics and craniofacial morphology in this group of patients. Oral photographs, study casts, profile radiographs, and orthopantomograms were analysed. The study showed that this group of SMMCI patients were characterized by an indistinct philtrum, an arch-shaped upper lip, absence of the fraenulum of the upper lip, a complete or incomplete mid-palatal ridge, a SMMCI, and nasal obstruction or septum deviation. The craniofacial morphology of the nine girls, compared with normal standards for girls showed a short anterior cranial base, a short, retrognathic and posteriorly inclined maxilla, and a retrognathic and posteriorly inclined mandible. Furthermore, the sella turcica had a deviant morphology in five of the 10 subjects. The results indicate that the presence of a SMMCI should not be considered as a simple dental anomaly, since it may be associated with other clinical characteristics and more complex craniofacial malformations. It is therefore suggested that the SMMCI condition in future studies is classified according to clinical symptoms and craniofacial morphology.

Comparison of the number and diameter of dentinal tubules in human and bovine dentine by scanning electron microscopic investigation.

Detailed information on dentine structure is essential for interpreting data from investigations on dentine-adhesive materials. The purpose here was to compare the number and diameter of dentinal tubules at similarly prepared surfaces of bovine permanent central incisors and human deciduous and third molars. In bovine teeth, crowns and roots were used; in human samples only the crowns were investigated. Tubule density in the middle layer was higher in bovine root (BR) dentine (number of tubules per mm(2)+/-SD: 23, 760+/-2453) than in human deciduous (HD) (18,243+/-3845), human permanent (HP) (18,781+/-5855), and bovine coronal (BC) (17, 310+/-2140) dentine. The corresponding values for the deep layer were 23,738+/-4457 (BR), 24,162+/-5338 (HD), 21,343+/-7290 (HP), and 20,980+/-4198 (BC). No significant differences were found for the number of dentinal tubules in bovine coronal dentine compared to the dentine of human deciduous and permanent molars. The mean diameter of bovine dentinal tubules was slightly, but not significantly, higher than in human dentine (middle layer/deep layer+/-SD): BC, 2. 85 microm+/-0.18/3.50 microm+/-0.33; BR, 3.10 microm+/-0.33/3.23 microm+/-0.30; HD, 2.55 microm+/-0.16/2.82 microm+/-0.28; HP, 2.65 microm+/-0.19/2.90 microm+/-0.22. These findings demonstrate that corresponding coronal dentine layers of human deciduous and permanent molars, and of bovine central incisors, are not significantly different in their number of tubules per mm(2) and their tubule diameter, whereas tubule density in bovine root dentine is significantly higher. These results suggest that provided standardized preparations are used, bovine incisor crown dentine is a suitable substitute for human molar dentine in adhesion studies.

A retrospective study of hearing, speech and language function in children with clefts following palatoplasty and veloplasty procedures at 18-24 months of age.

Many cleft palate teams currently schedule palatoplasty and veloplasty within the child's first year of life. At Hannover Medical School, palatoplasty and veloplasty are performed at approximately 18-24 months of age. It was questioned which speech and language outcome was achieved and whether it may be influenced by: (1) type and extent of the clefts; (2) velopharyngeal inadequacy; and (3) hearing disorders. A retrospective evaluation of data collected from 1985 to 1993 was performed summarizing receptive and expressive speech and language skills of 370 children aged 4.5 years. Cleft types were unilateral cleft lip and palate (UCLP, 30.0%), bilateral cleft lip and palate (BCLP, 28.7%), cleft hard and soft palate (CP, 21.6%), cleft soft palate (cleft velum, CV, 10.8%), cleft lip and alveolus (CLA, 5.8%) and submucous clefts (SUB, 3.2%). n = 86 had constant normal hearing, and n = 284 had conductive hearing loss > 20 dB (500-4000 Hz). Severe developmental phonology errors were found in 30-50% of children with repaired cleft palate and in less than 8% of patients with CLA and SUB. Posterior compensatory misarticulation was below 15% in the groups UCLP, BCLP, CP, CV and SUB. Nasal resonance and air emission was nearly normal in CLA, but was increased in 27% to 38% of the other cleft types. Children with conductive hearing loss had significantly more and severely affected phonology, morphology, syntax, vocabulary, language comprehension, and auditory perception than normal hearing children. Findings indicated that speech and language function in CLP patients were predominantly related to the hearing status.

Transverse changes after surgical closure of complete cleft lip, alveolus and palate.

Surgery for patients with unilateral (UCLP) and bilateral (BCLP) complete cleft lip, alveolus and palate has a considerable influence upon craniofacial growth. With respect to this, the cleft team at Hannover Medical School has attempted to reduce necessary surgical interventions to labioplasty, palatoplasty and veloplasty. Still, the effects of these operations influence maxillary growth to an extent which requires orthodontic treatment in all patients. This study focuses upon the transverse alterations of the alveolar arch and the deciduous dentition after lip and palate surgery. Dental casts prior to any surgical intervention and after labioplasty and complete palaotoplasty of the hard and soft palate were measured for transverse changes by using anatomical landmarks. The results indicate a significant occurrence of anterior relative to posterior arch width loss for both UCLP and BCLP patients. Orthodontic treatment should be planned and performed with respect to these findings in order to support craniofacial growth and prevent maxillary dental arch deficiency.

Bovine dentin as a substitute for human dentin in shear bond strength measurements.

PURPOSE: To evaluate the suitability of bovine coronal and root dentin as substitutes for human primary and permanent dentin in shear bond strength tests for dentin adhesives. MATERIALS AND METHODS: 30 bovine permanent central incisors, 30 human primary and 30 human third molars were cut mesiodistally. The pulpal and buccal dentin surfaces of the buccal cuts were milled with a bur to a thickness of 1.0 mm. A dentin adhesive and a hybrid composite were applied exactly according to the instructions given by the manufacturer on each buccal and pulpal surface, except in primary teeth where only the buccal surface was used. Shear bond strength was determined after 24 hours of storage in an aqueous solution. The results were statistically analyzed using the Wilcoxon- or the Mann-Whitney-U-test. RESULTS: There were no differences in shear bond strengths between human permanent dentin and bovine coronal dentin (13.3 +/- 6.1 vs. 15.2 +/- 7.6), and between each pulpal and buccal aspect. Significant differences were found between bovine root dentin and human primary dentin (17.4 +/- 8.3 vs. 7.7 +/- 5.0, P < 0.001). Significant differences were also found between bovine root dentin and human permanent dentin (17.4 +/- 8.3 vs. 13.3 +/- 6.1, P < 0.05), and bovine root and coronal dentin (17.4 +/- 8.3 vs. 15.2 +/- 7.6, P < 0.05). Furthermore, significant differences were recorded between human primary and human permanent dentin (7.7 +/- 5.0 vs. 13.3 +/- 6.1, P < 0.001) and bovine coronal dentin (7.7 +/- 5.0 vs. 15.2 +/- 7.6, P < 0.001).

Comparative survey of osteotomized and nonosteotomized BCLP patients.

OBJECTIVE: At Hannover Medical School, treatment of BCLP patients was revised and updated in 1980. The objective of the present study was to evaluate the differences in treatment outcome between BCLP patients treated after the revised concept including infant orthopedics, and BCLP patients who received osteotomy in addition to surgical and orthodontic treatment during childhood. PATIENTS: Nine of 48 BCLP patients born between 1980 and 1983 received surgical and orthodontic treatment according to the Hannover concept. They were compared to 9 of 68 adolescent and adult patients from Hannover without this protocol, who underwent maxillary osteotomy and consecutive orthodontic treatment. MAIN OUTCOME MEASURES: Comparison of the two groups was made at the end of active orthodontic treatment by cast analysis and lateral cephalometrics to evaluate sagittal, transverse, and vertical changes. RESULTS AND CONCLUSIONS: No patient treated using the revised protocol showed characteristics of skeletal angle class III at any stage of investigation. No indication for osteotomy was found in this group. All patients with osteotomy had skeletal angle class III resulting from insufficient midfacial growth. Sagittal and vertical skeletal relations were successfully improved by osteotomy.

Location of alveolar clefts relative to the incisive fissure.

OBJECTIVE: The purpose of this study was to investigate, in a normal human fetal sample, the development of the anterior area of the palate. Emphasis has been placed on the bilateral epithelial fusion lines between the soft-tissue palatal shelves and the premaxillary mucosa, and on the relationship between these fusion lines and the locations of the inclusive fissures and of the tooth buds. The goal was to evaluate how the location of clefts in cleft lip and palate (CLP) patients interferes with tooth buds that are often affected in clefting. DESIGN: Nineteen maxillas of human fetuses underwent histologic examination after serial horizontal sectioning. Superimpositions of tracings from photographs of the histologic sections yielded information on the maxillary morphology at different levels. RESULTS: After elevation and fusion of the soft-tissue palatal shelves, the palatal fusions were Y-shaped. During subsequent osseous palate development, including formation of the incisive fissure and intermaxillary suture, the Y-shaped epithelial fusions disintegrated. The locations of the anterior arms of the epithelial Y and of the incisive fissure did not coincide. CONCLUSIONS: The incisive fissure is likely not the location of clefts in CLP. The location of anterior palatal clefting in CLP patients follows the original course of the epithelial fusion between the palatal shelves and the premaxillary mucosa found in the region of the lateral incisors.

Phase-conjugate Fizeau interferometer.

We describe a phase-conjugate interferometer that consists of a partially transmitting conventional mirror placed in front of and in close proximity to a phase-conjugate mirror. The interferometer is self-referencing, compact, and insensitive to environmental disturbances, provides twice the sensitivity of conventional (nonphase-conjugate) interferometers, and produces a direct representation of an incident wave front. We have constructed such a device using internally self-pumped phase conjugation in barium titanate and have used the device to characterize the wave front produced by an aberrated optical system.

Epidemiological aspects of beryllium-induced nonmalignant lung disease: a 30-year update.

The unusual epidemiology of beryllium disease observed in the early studies of beryllium disease led in 1951 to the hypothesis that the chronic form of the disease is the result of an acquired sensitization to beryllium or its compounds. After 30 years, the role of sensitization has been confirmed in a number of laboratory and clinical studies. The unusual epidemiological features first summarized by Sterner and Eisenbud continue to be evident. The early studies also led to formulation of standards that have resulted in effective control of both the acute and chronic pulmonary forms of beryllium disease. No case of acute chemical pneumonitis has been reported among beryllium workers in about 15 years, and the number of chronic cases has diminished greatly despite a marked increase in the use of beryllium.