PubMed Health⌕ Search

Biomedical subjects

J Kleinheinz

Publications and source records attributed to J Kleinheinz.

29 records · Page 2Linked to original sources
PubMed1999

Reproducible X-ray projection geometry in edentulous patients.

OBJECTIVE: To evaluate a novel fixation system for reproducible radiography in edentulous patients. METHODS: A conventional extra-oral fixation system was modified with a filmholder and adjustable scales. For measuring reproducibility and angulation errors two rods and two balls were fixed on the alveolar crests of the maxilla and the mandible and angular variations were measured. One hundred radiographs of a conventional phantom were taken by one of the authors and by ten dental students. The angular disparity was calculated and intra- and interoperator precision determined. RESULTS: The average time taken to assemble the fixation system was 4 min. The 95% confidence interval for precision of the single operator was less than 2.5 degrees in both the maxilla and mandible. The 95% confidence interval for precision of the ten students was less than 2.2 degrees for the maxilla and 2.7 degrees for the mandible. There was no significant difference (P>0.05) in interoperator precision. CONCLUSION: The novel extra-oral fixation system appears to be a potential means of obtaining reproducible radiographs of edentulous patients.

Humans↗
PubMed1999

Three-dimensional visualization and quantification of the mandibular articular surface by optical profilometry.

The aim of this study was to introduce a nondestructive optical technique for the quantitative assessment of natural biological surfaces as demonstrated with the example of the articular surface of the human temporomandibular joint. The computer-assisted quantitative evaluation of the surface is realized by the acquisition of three-dimensional images via the optical technique of phase measuring profilometry. After mathematical processing of the data set the resulting image can be visualized as three-dimensional object surface reconstructions or as grid surfaces from which arbitrary sections may easily be extracted. From such single sections we can calculate a value that represents the degree of height deviations of the section profile and can be regarded as a parameter for the surface roughness. Further quantitative information about the surface topography is provided by the Fourier transform analysis of the profiles. The Fourier spectrum contains information about the spatial distribution of roughness-causing protuberances along the overall surface. As an example one healthy condyle and one remodeled condyle from macerated cadaver mandibles were investigated. For the two samples evaluated we calculated a mean surface roughness of the entire articular surface with a value of 0.03 +/- 0.005 mm for the healthy condyle with its smooth surface and a value of 0.14 +/- 0.009 mm for the remodeled condyle. We recommend optical profilometry as a sophisticated technique for a more objective and quantitative pathological classification of articular surfaces and similar objects.

Fourier Analysis↗
PubMed1999

Indications for treatment of subcondylar mandibular fractures.

BACKGROUND AND OBJECTIVES: The purpose of this study was to establish a reliable criteria for implementation of either an open surgical or a closed conservative treatment of subcondylar fractures, based on clinical data and analytical mathematical model. METHODS AND MATERIALS: A total of 512 subcondylar fractures were treated during a 3-year period. Of these, 256 were fractures characterized by either displacement or dislocation of the proximal (condylar) segment. Patients were treated with open reduction and internal fixation (ORIF) or closed reduction (CR) techniques. Patients were evaluated pre- and postoperatively by clinical examination, 3-dimensional axiography, radiographic imaging, and ultrasonography. A mathematical model was developed for estimating the loss of vertical ramus height. RESULTS AND/OR CONCLUSIONS: When the displacements were less than 37 degrees from the sagittal axis of the ascending ramus, the ensuing loss of vertical height was negligible when fractures were treated by conservative techniques. When the displacements exceeded 37 degrees, the fractures resulted in a significant decrease of vertical ramus height. Based on these data, 37 degrees appears to be the point for decision of whether to use closed or open treatment.

Adolescent↗
PubMed1998

[MRI 3D imaging of the orbits in craniofacial abnormalities and injuries].

Craniofacial malformations and trauma often lead to changes in orbital soft tissues that require operative correction of both hard and soft tissues. CT scan and 3D reconstructions are optimal tools for the evaluation of the bony structures but there is no equivalent for the orbital soft tissues. The aim of this study was to establish a 3D-MRI technique that allows differentiated visualization of the different soft-tissue types of the orbit. A total of eight patients with different pathologic conditions of the orbit were examined. Five of these patients came for secondary correction after trauma and three showed a craniofacial malformation. 3D reconstruction was performed in volume-rendering technique after acquisition of 3 mm axial slices. It was shown that differentiated visualization of the orbital soft tissues is possible. Even though the thin bony structures have a weak signal and therefore the imaging is poor, the globe could be reconstructed reliably by different radiologists because of its circular delimitation from the bone. This technique provides additional support in the planning of orbital operations.

Craniofacial Abnormalities↗
PubMed1998

[Prospective study of the pathology of radiation-induced mucositis].

One of the most severe early side effects of radiation in head and neck cancer patients is mucositis. Inflammation of the oral mucose may lead to an extreme subjective burden, restricting the patients' well-being and even leading to an interruption of radiotherapy. The aim of our prospective study was to investigate the pathological alterations of the oral mucosa during irradiation. Therefore, samples from head and neck cancer patients were taken before radiation and a 30-G and a 60-G radiation dose. Pathogenetic alterations were determined by immunohistochemical staining of various cell surface molecules known to be involved in the pathogenesis of inflammation. Staining was performed with antibodies against ICAM 1, VCAM 1, ELAM, 25F9, 27E10, and RM3-1. Our study demonstrates the expression rates of the various surface molecules during inflammation. Expression of RM3-1 and ICAM 1 showed a steep increase during the time of radiation, whereas expression of ELAM reached a low constant value. Therefore, we conclude that distinct cell surface molecules demonstrate a characteristic time-dependent expression during radiation. Better insight into the pathogenesis of radiation-induced mucositis may help to develop a pathological classification of mucositis and to improve therapeutic strategies.

Aged↗
PubMed1998

[Gigantic proliferating trichilemmal cyst of the scalp with central carcinoma and lymph node metastasis].

We report the case of a 77 year old woman with a giant proliferating trichilemmal cyst of the scalp and a central squamous-cell carcinoma. Six months after radical tumor-excision and dissection of the locoregionary lymph nodes the patient developed retroclavicular lymph node metastases. The tumor develops from cells of the hair matrix and tends to recur after excision; in rare cases malignant transformation may occur. We suggest radical excision and complete histological examination of the tumor. In cases of malignancy, lymph node-dissection is sometimes necessary. In these cases close postoperative follow-up of the patient is mandatory.

Aged↗
PubMed1997

[Oral manifestations of acute leukemia].

It is well known that non-specific mucosal alterations can occur during diseases of the leukopoetic system. In most cases they are an early sign and therefore provide the opportunity for timely diagnosis of the disease. In this clinical study type and frequency of oral lesions, gingival and periodontal indices, and hematologic status were examined at the time of diagnosis of the different types of acute leukemia. The results showed a significant difference in the frequency of oral lesions between acute myelogenous and acute lymphoblastic forms, irrespective of age and sex of the patient. There was no correlation between type and frequency of lesions and hematologic status.

Adult↗
PubMed1997

[Oral manifestations in patients with systemic lupus erythematosus].

Forty-six patients with systemic lupus erythematosus underwent thorough dental examination to determine the frequency and severity of oral lesions and periodontal diseases. According to clinical criteria, disease was classified as severe (n = 26) or less severe (n = 20). The overall rate of mucosal involvement in the studied patients was 48%-from 54% in patients with severe disease, 40% in those with less severe disease. Patients with severe disease were found to have a higher rate of tooth loss and an increased rate of gingival inflammation. The severity of periodontal lesions correlated with alterations in the immunoglobulin pattern, particularly with an increase in gamma-immunoglobulins. Thus it is suspected that complex immunodysregulation in combination with immunosuppressive therapy is responsible for the high rate of oral and periodontal lesions in patients with systemic lupus erythematosus.

Adult↗
PubMed1997

Ultrasonographic versus conventional diagnostic procedures in dislocated subcondylar mandibular fractures.

In patients with severe craniomaxillofacial trauma, immediate attention is directed primarily to the early diagnosis of cervical spine injuries, intracranial injuries, respiratory difficulties, and vascular compromises. Diagnostic studies, such as computed tomography scans, are sometimes not useful for the evaluation of mandibular fractures, since cuts are performed too superiorly. The plane radiographs obtained in emergency settings are frequently of minimal diagnostic value. Fractures of the mandibular symphysis, body, and angles are easily identified clinically; subcondylar fractures, however, are not directly accessible for clinical examination. The evaluation of suspected dislocated subcondylar fractures with the aid of ultrasonography is reliable, highly sensitive and specific, and cost-effective.

Cost-Benefit Analysis↗
PubMed1991

Sucking efficiency of early orthopaedic plate and teats in infants with cleft lip and palate.

Intraoral negative pressure during bottle feeding with two kinds of teats (a regular Nuk and a cleft Nuk) was measured in 7 infants with cleft lip and palate, 8 infants with cleft palate, 2 infants with cleft lip, 4 infants with operated cleft lip and palate and 7 normal infants. Infants with cleft lip and palate or cleft palate were unable to generate negative pressure before cleft lip and palate closure. The presence or absence of an early orthopaedic plate did not make any difference. In infants with unoperated cleft lip and with operated cleft lip and palate, peak negative pressure during feeding differed little from that of normal infants.

Bottle Feeding↗