Biomedical subjects

R Schmelzle

Publications and source records attributed to R Schmelzle.

At least 19 recordsLinked to original sources

PubMed2005

Eruption times of permanent teeth in children and young adolescents in Athens (Greece).

In a study in Athens, Greece, during the summer of 2003, 2,304 patients (1,168 boys and 1,176 girls) were examined by a young dentistry. The examination occurred within the framework of a routine dental check-up performed at the National and Kapodistrian University of Athens. The age span ranged from 3.00 to 24.93 years of age. Sex, age and present permanent teeth were recorded. Wisdom teeth were excluded. The sequence of tooth eruption differs significantly in the lower and upper jaw, whereas no significant differences existed when comparing the sides of each jaw. The tooth eruption in the lower and upper jaw of male and female probands is symmetrical. In comparing the upper and the lower jaw of both genders, it becomes evident that there is a tendency for earlier tooth eruptions in the lower jaw. In respect to the tooth eruption sequence, a change was noted in the upper jaw. Contrary to the reports of other authors, the second premolar has changed places with the canine and erupts prior to this tooth. This could also be demonstrated in recent studies from New York and Bremen (Germany). Otherwise no major differences concerning the sequence of tooth eruptions were observed, when compared with the results gained from other populations. Concerning the entire dentition, no acceleration of the tooth eruption could be noted. The computed differences of teeth eruption as a mean value calculated over all teeth was +/-1 year at maximum, compared with studies from different continents. Oral examination of teeth is a simple tool to calculate tooth eruption intervals. This first investigation in a population of Athens revealed a change in the eruption sequence of permanent teeth. These findings are relevant for dental treatment planning and should be reconfirmed at certain intervals.

Adolescent↗

PubMed2005

Intraoperative imaging of zygomaticomaxillary complex fractures using a 3D C-arm system.

After preclinical studies and evaluation of radiation exposures, intraoperative three-dimensional (3D) C-arm based imaging is now available for the facial skeleton. Fourteen patients admitted for surgical treatment of zygomaticomaxillary complex (ZMC) fractures were included in the study. Preoperative diagnostics and surgical treatment were performed as usual. Intraoperatively, after open reduction, a cone-beam computed tomography (CBCT) dataset was generated using the SIREMOBIL Iso-C3D (Siemens Medical Solutions, Erlangen, Germany). After DICOM-import in eFilm Workstation axial, coronal and sagittal reconstructions were evaluated by five examiners with the help of six defined criteria. In our study, secondary reconstructions were available after 6 min, excluding the time needed for the evaluation of the images. Especially the positioning of the isocentre of the SIREMOBIL Iso-C3D proved to be uncomplicated. Because of the size of the datasets, assessment of the symmetry of the malar projection proved difficult. Best scoring results were found regarding the visualization of the fragment position, bony anchorage of the screws and the fitting of the plates. Remarkable was the low level of metal artefacts in primary and secondary reconstructions. In conclusion, our results demonstrate intraoperative CBCT using the SIREMOBIL Iso-C3D suitable for assessment of postoperative results following ZMC reduction.

Adult↗

PubMed2005

[The eruption times of permanent teeth in boys and girls in the Stormarn District, Schleswig-Holstein (Germany)].

UNLABELLED: In a longitudinal study in two small towns in southern Schleswig-Holstein (Ammersbek and Ahrensburg, District Stormarn; 9155 inhabitants) we investigated 2832 oral findings of 1396 patients (711 males, 685 females). The minimum age was 1.51 years, and the maximum age was 25.50 years. The dental findings were collected over a period of about 20 years (1982-2002). The oral findings per child were assessed between one and eight times. The eruption times of teeth in females are earlier than those for the same teeth in males. Further, the permanent dentition in females is completed earlier than in males. In both sexes the tooth eruption occurs symmetrically in both jaws. The comparison of both jaws revealed a slightly advanced eruption of the lower jaw teeth in both sexes. There is a noteworthy change in the eruption sequence of the teeth. In contrast to other reports we observed that the eruption of the canine proceeds the eruption of the second molar. We found no acceleration of the dentition when compared with other reports and could confirm the rules of tooth eruption in man. CONCLUSION: Oral examination of teeth is a simple tool to calculate tooth eruption intervals. This first investigation on a population of Schleswig-Holstein revealed a change in the eruption sequence of permanent teeth. These findings are relevant for dental treatment planning and should be reconfirmed at certain intervals.

Adolescent↗

PubMed2004

[Experiences in the treatment of midfacial fractures using a fixed-angle osteosynthetic system. Biomechanical results].

AIM: Fixed-angle osteosynthetic systems are characterized by mechanical "locking" of the osteosynthetic screw and plate. These systems have found increasing acceptance and use for osteosynthetic fixation and temporary reconstruction of the mandible. The aim of this study was to investigate the applicability and performance of fixed-angle systems in the treatment of midfacial fractures. MATERIAL AND METHOD: A newly developed fixed-angle osteosynthetic plate system (smart lock) was compared to a conventional system using fresh human skulls. The iatrogenically produced zygomatic fractures of the human skulls were treated by osteosynthesis and biomechanically tested. Furthermore, in a dynamic test series, an artificial bone was subjected to an alternating force of 15 N of up to 1,000,000 cycles. The new screws and plates were subjected to further biomechanical tests. RESULTS: The tests using the fixed-angle implants revealed that an increase of stability of up to 40% can be expected after osteosynthetic fixation. Furthermore, the plates resisted 1,000,000 cycles of alternating forces, whereby the conventional systems failed after 170,000 cycles on the average. CONCLUSION: Fixed-angle systems, due to their construction, provide a high degree of stability even in thin bones of the midface. They appear to be promising for the treatment of midfacial fractures.

Bite Force↗

PubMed2004

[Sonography as a training tool for screening of dubious midfacial fractures].

BACKGROUND: In uncertain midfacial fractures, sonography is an alternative first-line imaging modality to conventional radiographs. Patients with sonographically confirmed fractures can then be directly admitted to three-dimensional imaging, resulting in decreased radiation exposure since the conventional radiographs are omitted. MATERIAL AND METHODS: Using a high-frequency linear and curved array scanner in a healthy proband, images of the zygomatic arch, anterior maxillary sinus wall, infraorbital rim, and lateral orbital wall were obtained. For identification and anatomical allocation corresponding navigated ultrasound images of a reference skull were generated and fused with a segmented CT data set. Navigated sonography was reproduced in a patient with orbitozygomatical fracture of the left side. Therefore, the CT data set, performed during preoperative diagnostics, was fused with the ultrasound images. RESULTS: Because of different coupling shapes, the high-frequency linear array scanner was subjectively found to be more suitable for sonography in the field of the zygomatic arch, anterior maxillary sinus wall, and infraorbital rim, and the curved array scanner was better suited for transbulbar sonography of the orbital walls. After coupling sonography with the navigation system and referencing the scanner, it was possible to verify ultrasound findings objectively by navigation of the scanner and fusion with the CT data set. Using the reference skull, ultrasound images corresponding to normal findings were obtained and with the fused CT data, providing colored segmentation of the facial bones, an anatomically correct identification was possible. Clinical application of this tool is described in a patient with left-sided orbitozygomatical fracture. CONCLUSION: By fusion of ultrasound images and corresponding CT data with the help of a navigation system, a sonographic training tool for preliminary evaluation of midfacial fractures is available.

Diagnosis, Computer-Assisted↗

PubMed2004

[Virtual simulation of dental surgery using a three-dimensional computer model with a force feedback system].

BACKGROUND: Selective reduction of bone without injuring inner structures is an essential part of surgical techniques, especially during dental surgery. Virtual drilling is possible using a new simulator. The following illustrates simulation of an apicectomy. MATERIAL AND METHODS: Using the VOXEL-MAN system, a virtual three-dimensional model of a skull was created based on CT data. Both inferior alveolar nerves and apical inflammations of teeth 23, 25, 36, and 35 were virtually simulated. To achieve a realistic drilling effect with the force feedback system, special tools were integrated into VOXEL-MAN to obtain a high resolution of collision recognition. Adding drilling noises further improved the simulation. Spatial 3D perception was possible with the help of shutter glasses. RESULTS: The presented computer model enabled the visual and haptic observation of complex volume-based models and virtual interaction with them. The haptic feeling proved to be convincing because of collision recognition, consideration of drilling parameters, and addition of drilling noises. Via postoperative reconstructions, polydimensional verification of performed drilling routes is possible. CONCLUSION: Using apicectomies as examples, realistic simulation of dental surgical procedures, even in complex anatomical models, is possible. Generally, it is possible to add virtual pathologies in data sets and/or to use anonymous patient data sets to extend the range of simulated surgical procedures.

Apicoectomy↗

PubMed2004

[Radiation exposure and 3 dimensional imaging options of SIREMOBIL Iso-C(3D) for planning surgical dental interventions].

BACKGROUND: Preoperative dental X-ray diagnostics of multimorbid, non compliant patients requiring dental surgery are often insufficient. The SIREMOBIL Iso-C(3D) has made intraoperative 3D imaging available, even for the facial skeleton. This modality was used intraoperatively in two patients referred for surgical dental treatment. Furthermore, radiation exposure of the SIREMOBIL Iso-C(3D), an orthopantomography and a complete dental status was compared. MATERIAL AND METHODS: An Alderson-Rando phantom was exposed to ten cycles of the SIREMOBIL Iso-C(3D) using the fast mode (50 projections). In comparison 28 panoramic views of an Orthophos and 10 sets of 14 dental images using the Oralix DC with a quadrate mask were applied. Twenty-five anatomically defined TLD positions were analyzed. Furthermore, SIREMOBIL Iso-C(3D) was used in one patient by performing 100 projections and in a second patient by performing 50 projections. After DICOM-import in eFilm, axial, coronal, and sagittal reconstructions were evaluated by five examiners regarding defined criteria. RESULTS: The radiation exposure level of the SIREMOBIL Iso-C(3D) was lower than in the complete dental status and only slightly higher in comparison with the orthopantomography, although the system requires the highest number of single projections. Quantitative evaluation of the visualization and recognition of defined structures proved to be very good and good in most points. However, limitations of the system became obvious regarding apical processes. CONCLUSION: Because of the dosimetry results and the visualization of the relevant structures, in patients for whom preoperative images cannot sufficiently be performed, the intraoperative use of the SIREMOBIL Iso-C(3D) as a base examination is justified.

Adult↗

PubMed2004

Eruption times of permanent teeth in teenage boys and girls in Izmir (Turkey).

In a study in the Aegean city of Izmir, Turkey, during the summer of 2002, 2101 patients (1046 boys and 1055 girls) were examined. The examination occurred within the framework of a dental check-up performed at two schools and one pre-school unit. The age span ranged from 3.98 to 24.91 years. Sex, age and present permanent teeth were recorded. Wisdom teeth were excluded. The sequence of tooth eruptions differs significantly in the lower and upper jaw, whereas no significant differences existed when comparing the sides of each jaw. The times of tooth eruption is earlier in females than in males. The entire tooth eruption process of the second dentition occurs in females earlier than in males. The tooth eruption in the lower and upper jaw of male and female probands is symmetrical. In comparing the upper and the lower jaw of both genders, it becomes evident that there is a tendency for earlier tooth eruptions in the lower jaw. In respect to the tooth eruption sequence, a change was noted in the upper jaw. Contrary to the reports of other authors, the second premolar has changed places with the canine and erupts prior to this tooth. Otherwise no major differences concerning the sequence of tooth eruptions, when compared to the results gained from other populations, were observed. Concerning the entire dentition, no acceleration of the tooth eruption could be noted. The computed differences of teeth eruption as a mean value calculated over all teeth, was +/- 1 year at maximum, compared to studies from different continents. Oral examination of teeth is a simple tool to calculate tooth eruption intervals. This first investigation on a population of Izmir revealed a change in the eruption sequence of permanent teeth. These findings are relevant for dental treatment planning and forensic odontology and should be reconfirmed at certain intervals.

Adolescent↗

PubMed2004

Intraoperative 3D imaging of the facial skeleton using the SIREMOBIL Iso-C3D.

OBJECTIVES: With respect to high-contrast structures, cone beam computed tomography (CBCT) offers an alternative imaging modality to computed tomography (CT), requiring less radiation exposure. The C-arm system SIREMOBIL Iso-C3D for three-dimensional (3D) reconstruction has made this modality available for intraoperative use. This paper presents the first intraoperative images of the facial skeleton using the SIREMOBIL Iso-C3D. METHODS: Cases of a zygomaticomaxillary complex fracture, a mandibular angle fracture and a bimaxillary repositioning osteotomy are described to demonstrate the application possibilities of this system in maxillofacial surgery. RESULTS: In addition to the uncomplicated handling of the SIREMOBIL Iso-C3D, generally important was the low level of metal artefacts in its primary and secondary reconstructions, even in close proximity to the material. However, it has to be kept in mind that while soft tissues are visualized using CBCT, information about soft tissue quality cannot be obtained. CONCLUSION: The SIREMOBIL Iso-C3D generates intraoperative data sets suitable for the visualization of the facial bones after open reduction of fractures.

Adolescent↗

PubMed2003

[3-dimensional imaging possibilities of thhe mid-face area using digital volume tomography based on a daver study of angle stable osteosynthesis].

BACKGROUND: Multidirectional angularly stable interlocking plate systems are now available for the surgical treatment of the midface. After first experiences in cases of mandibular fractures, application to the facial skeleton was investigated using a cadaver study. Furthermore, three-dimensional imaging by means of the digital volume tomograph NewTom DVT 9000 after reduction of orbitozygomatical fractures was performed and evaluated. MATERIAL AND METHODS: After artificial osteotomy and reduction of both zygomatical complexes, osteosynthesis of the left side was performed with three 4-hole miniplates (2.0). On the right side, three angular stable 2-hole plates (2.3) were used. Thereafter, a three-dimensional data set was generated using the NewTom DVT 9000. After DICOM-import in eFilm reconstructions were evaluated by six examiners regarding defined criteria. RESULTS: After adaptation and fixation of the angular stable interlocking plate system without complications, manual checking revealed that the primary stability did not seem inferior to the other side. Defined criteria were sufficiently evaluable, even close to the osteosynthetic material, using reconstructions of the digital volume tomography data set. CONCLUSION: Surgical treatment of midfacial fractures using a multidirectional angularly stable interlocking plate system seems promising. The NewTom DVT 9000 proved to be suitable to visualize even fine osseous structures of the midface.

Bone Plates↗

PubMed2003

3D-imaging of the facial skeleton with an isocentric mobile C-arm system (Siremobil Iso-C3D).

OBJECTIVES: The purpose of this study was to compare three-dimensional (3D) imaging of the facial skeleton using an isocentric mobile C-arm system vs CT. METHODS: A dried human skull was scanned using a Siremobil Iso-C3D and a multi-detector CT (SOMATOM Volume Zoom; Siemens Medical Solutions, Erlangen, Germany) to compare reconstructed data sets. For each group of scans a standard protocol and a high resolution protocol were used. Image quality was analysed using six anatomical and six virtual structures in the primary reconstructed axial images of both data sets of the Siremobil Iso-C3D compared with CT. A receiver operating characteristic (ROC) study was performed with six examiners. RESULTS: The original categorical response data revealed no significant differences in sensitivity and specificity (P < 0.05). However, image quality of the reconstructed images of the Siremobil Iso-C3D was inferior to the CT images, with metal artefacts having a more prominent negative effect. CONCLUSIONS: The Siremobil Iso-C3D produces 3D images of the facial skeleton suitable for imaging osseous structures. No significant differences were found in sensitivity or specificity between the two methods. Metal objects degrade the image from the Iso-C method to a greater extent than those from CT.

Artifacts↗

PubMed2002

[Involvement of the maxillary sinus in Langerhans cell histiocytosis].

AIM: A clinical presentation of Langerhans cell histiocytosis (LCH) in the maxillary sinus of two patients is given. LCH in the maxillary sinus is a rare occurrence. Our aim was to compare the different treatment alternatives available and to suggest a classification as well as a therapeutic regime. PATIENTS AND METHOD: Records and clinical data of two patients treated between 1994 and 2001 were retrospectively evaluated. Both patients suffered from LCH in the maxillary sinus and the maxilla regions. Only surgical treatment was used. After resection, a large defect of the maxillary sinus, which did not allowing coverage, was seen in both cases. After reconstructive operations, closure was finally achieved. Both patients underwent follow-ups, whereby one suffered from a relapse after 15 months. RESULTS: Although one of the patients under investigation showed a recurrence of LCH, we are of the opinion that surgical treatment is very effective in the elimination of this condition. A proposal for a classification of LCH in the oral-maxillo-facial-region is made. CONCLUSIONS: The evaluation of our clinical study suggests that LCH is a disease that should be treated surgically. Only in very severe cases should the surgical treatment be complimented by either radiotherapy or chemotherapy. In disseminated cases, especially chemotherapy seems to improve the outcome. Surgery offers the possibility of eliminating systemic side effects.

Dental Implantation, Endosseous↗

PubMed2002

Clinical and histological results of sensory recovery after radial foreann flap transfer.

The necessity of nerve anastomosis in an attempt to regain dermal sensitivity following pedicled or free-flap transfer has been the basis of many discussions. In our study, we investigated the degree of sensory recovery with emphasis on the different nerval qualities, on the radial forearm flap and correlated it to the histological and immunohistological findings. Nineteen patients with radial forearm free flap--five of whom underwent nerve anastomosis--were examined. The follow-up interval was 20.3 months (average) after surgical intervention. Histological examinations were performed on 13 of the 19 patients, in eight cases on one occasion and in five on more than one occasion. Seventeen patients experienced sensory recovery, whereby the degree and quality of dermal innervation varied. In comparison, the nerval reconstruction did not lead to any significant improvement. Based on our clinical results, we regard the nerve reconstruction during the radial forearm free flap transfer as unnecessary. To what extent this can be said for other flaps demands further investigation.

Adolescent↗

PubMed2002

[Experimental and histomorphologic studies of healing processes of anastomoses of the carotid artery in the Wistar rat animal model with immunohistochemical imaging of collagen IV].

INTRODUCTION: The main risk in free flap tissue transfer is posed by the microvascular anastomosis. The dangers confronting the anastomosis are thrombosis, aneurysm, and vascular insufficiency. Collagen IV is associated with the basement membrane complex. It plays an essential role in vascular tissue organization and supports mechanical properties of vessels. We used a long-term animal experiment to gain a new understanding of histomorphological apposition of anastomosis and distribution of collagen IV. METHODS: Seventy Wistar rats, seven groups of ten animals each, were operated. A 4-mm long segment of the common carotid artery was isolated and reinserted. After a varying length of time (between directly after the operation and 6 months later), the common carotid arteries including bifurcation were isolated after cardiovascular perfusion. Carotid arteries were embedded, and cross-sections were stained with hematoxylin and eosin, Verhoeff's tissue elastin stain, and immunohistochemical anti-collagen IV antibody. By using the above-described technique in each section four anastomoses were examined. The histomorphology and intensity of the anti-collagen IV stainings were evaluated. RESULTS: Compression, shift, and dehiscence as forms of vessel apposition were often seen. We observed an overexpression of collagen IV in the media in cases of compression and shift. The grade of expression of collagen IV in the anastomosis depends on the extent of the injury. CONCLUSIONS: A well-performed microvascular anastomosis is clinically important not only for the acute phase after the operation, but also for the long-term course. The application of antibodies to identify the collagen IV distribution is valuable for studying vascular healing. Further applications could be used in follow-up studies of vascular prostheses.

Anastomosis, Surgical↗

PubMed2002

[Clinical outcome of re-innervation of radial flaps and latissimus dorsi muscle transplants].

BACKGROUND: The necessity of nerve anastomosis in an attempt to regain cutaneous sensitivity following flap transfer has been the basis of many discussions. In our study, we investigated the degree of sensory recovery with emphasis on the different nerval qualities on the radial forearm and the latissimus dorsi flap. COLLECTIVE: Sixty-two patients with 66 latissimus dorsi flaps and 19 patients with a radial forearm free flap were examined. RESULTS: Except for five latissimus dorsi and two radial forearm flaps, all flaps investigated showed clinical signs of sensory recovery, whereby the degree and quality of cutaneous reinnervation varied. In comparison, neural reconstruction did not lead to any clinical improvement. CONCLUSION: Based on our clinical results, we consider nerve reconstruction during radial forearm and latissimus dorsi free flap transfer unnecessary. To what extent this can be said for other flaps requires further investigation.

Adolescent↗

PubMed2002

[Abnormalities of the maxillary sinus in type 1 neurofibromatosis].

AIM: The aim of this study was to determine the malformations of the maxillary sinus in neurofibromatosis type 1 patients (NF1). MATERIAL AND METHODS: Twenty-two patients with NF1 were investigated clinically and radiologically: 11 had an unilateral trigeminal plexiform neurofibroma and 11 had multiple cutaneous neurofibromas. The histological type of NF was ascertained in all cases following tumor resections. The malformation of the maxillary sinus was assessed on plain radiographs and computed or magnetic resonance tomograms. Intraindividual side comparison was used to judge the size of the sinus and its position in the midface. RESULTS: In patients with cutaneous neurofibromas the maxillary sinus appeared symmetrical in size and position. The pneumatization of the sinus had no abnormalities on the radiographs. Malformations of the maxillary sinus were restricted to plexiform neurofibromas. On the side affected by a plexiform NF, the sinus appeared hypoplastic and caudally displaced due to an enlarged ipsilateral orbit. The expansion of the sinus to the lateral side was impaired, obviously due to tumor masses. Consecutively, the alveolar process of the affected side was also displaced leading to a complex malocclusion. DISCUSSION: Malformations of the face are frequently presented as case reports in the literature. Emphasis is given to the elephantiasis-like tumor growth of the face in certain patients with NF1. The underlying pathology has not yet been fully understood. This report provides evidence that in the midfacial region the overgrowth is predominantly caused by the plexiform neurofibroma itself and that the bones can even be hypoplastic and show scoliosis-like malformation compared to the nonaffected side. These findings are relevant when debulking procedures of the face are planned for NF1 patients.

Adolescent↗

PubMed2001

Limitations of B-scan ultrasound for diagnosing fractures of the mandibular condyle and ramus.

The aim of this study was to analyse the applications and limitations of B-scan ultrasonography for diagnosing fractures of the mandibular condyle and ramus. Thirty-two patients with 39 radiologically proven fractures of the mandibular condyle and ramus were included in the study. The patients were examined with a 7.5 MHz small-part applicator. Five patients without fractures of the facial skeleton acted as controls. Normal sonoanatomical findings had been obtained for patients without mandibular fractures. B-scan ultrasonography enabled the experienced examiner to identify dislocated fractures of the mandibular ramus and the articular process in 67% of the fractures. The main disadvantage of ultrasonography was the inability of this technique to identify non-dislocated fractures. Because of its low sensitivity and specificity, B-scan ultrasonography does not provide an alternative to X-ray diagnosis of mandibular condyle and ramus fractures.

Adolescent↗

PubMed2001

[Acute temporomandibular joint arthritis after Lyme borreliosis].

CASE REPORT: This report is about a rare connection between Lyme disease and an inflammation of the left temporomandibular joint. In this case, an infection was documented in 1998, 5 years after contact with Borrelia burgdorferi. The patient, a 49-year-old female, first came to our department in 1999. She showed the symptoms of a left temporomandibular joint infection. THERAPY: We suggested treatment with ceftriaxone 1 x 2 g/day i.v.

Diagnosis, Differential↗