Search PubMed⌕ Search

Biomedical subjects

F Härle

Publications and source records attributed to F Härle.

At least 19 recordsLinked to original sources
PubMed1999

The self adapting washer for lag screw fixation of mandibular fractures: finite element analysis and preclinical evaluation.

Besides rigid fixation, lag screws have distinct advantages compared with plates in appropriate indications in mandibular fractures. However, in current lag screw systems, the relatively small area of the screw head has to transfer the tensile force which can exceed 1000 N in the symphysis, to the thin cortical bone plate. Countersinking, which is obligatory in most systems, will weaken the cortical plate. Finite element analysis (FEA) revealed that load in this situation can exceed the normal tensile strength of metal and bone. Consequently, a new washer was constructed which both increased the supporting surface and did not require countersinking. The washer is self adapting (SAW) to the cortical plate in a defined position, forming a ball and socket joint with the screw head. Using the FEA model, a ten-fold reduction in load on bone and metal was observed with the new washer. In a miniature pig mandibular symphysis fracture model, the clinical applicability and a favourable histological reaction were demonstrated, compared with conventional lag screw designs.

Alloys↗
PubMed1994

Preoperative radiochemotherapy and radical surgery in comparison with radical surgery alone. A prospective, multicentric, randomized DOSAK study of advanced squamous cell carcinoma of the oral cavity and the oropharynx (a 3-year follow-up).

A multicentric, randomized study of squamous cell carcinoma (SCC) of the oral cavity and the oropharynx has been undertaken by DOSAK. The results after radical surgery alone have been compared with the results of combined preoperative radiochemotherapy followed by radical surgery. Patients with primary (biopsy proven) SCC of the oral cavity or the oropharynx with tumor nodes metastasis (TNM) stages T2-4, N0-3, M0 were included in the study. A total of 141 patients were treated by radical surgery alone, whereas 127 patients were treated by radical surgery preceded by preoperative radiochemotherapy. The preoperative treatment consisted of conventionally fractioned irradiation on the primary and the regional lymph nodes with a total dose of 36 Gy (5 x 2 Gy per week) and low-dose cisplatin chemotherapy with 5 x 12.5 mg cisplatin per m2 of body surface during the first week of treatment. Radical surgery according to the DOSAK definitions (DOSAK, 1982) was performed after a delay of 10-14 days. During the follow-up period, 28.2% of all patients suffered from locoregional recurrence, and 27.2% of the patients died. The percentages were higher after radical surgery alone for locoregional recurrence (31% and 15.6%) and for death (28% and 18.6%). The life-table analysis showed improved survival rates of 4.5% after 1 year and 8.3% after 2 years in the group of patients treated with combined therapy. The demonstrated improvement appeared to be significant with the Gehan-Wilcoxon test as well as with the log rank test below a P value of 5%.

Carcinoma, Squamous Cell↗
PubMed1991

[Active canine tooth movement by spongiosa graft in bilateral cheilognathopalatoschisis].

Bone grafting in the alveolar cleft offers a bony support in the alveolar process for the erupting canines and should be performed before the eruption of the teeth starts. Although bone grafting is done in time, the eruption of the canines does not always follow spontaneously. This is why a simultaneous ligation of the canines is sometimes indicated. The ligature can be threaded through the bone graft. Active eruption of the canines can begin eight weeks post operation. This procedure ensures a proper alignment of the canines in a well-defined processus alveolaris. The method is demonstrated in a bilateral cleft lip and palate patient.

Bone Transplantation↗
PubMed1991

Augmentation of the alveolar ridges with hydroxylapatite in a Vicryl tube.

The technique discussed describes the use of a Vicryl tube for maintaining hydroxylapatite (HA) granules in their correct position when augmenting the atrophic maxillary or mandibular alveolar ridge. The method involves simultaneous submucous vestibuloplasty in both the maxilla and the mandible and is also combined with lowering of the floor of the mouth. 118 patients (73 women and 45 men) were treated by this method. The results of augmentation in 64 maxillary and 54 mandibular cases are presented.

Acrylic Resins↗
PubMed1991

DNA-cytometric detection of euploid polyploidization in oral lichen ruber planus.

The DNA distribution was analyzed in 29 cases of oral lichen ruber planus that were negative for human papillomavirus and not suspected of being precancerous. Monolayer smears prepared from formalin-fixed, paraffin-embedded tissues were automatically Feulgen stained and used for rapid interactive DNA cytometry via a TV-based image analysis system combined with an automated microscope. Nuclei with DNA contents greater than 4c were found in 25 cases (86%). DNA contents greater than 8c were seen in five cases (17%), and small peaks at 8c were found in three cases. These increased DNA values in nonprecancerous lesions must be interpreted as euploid polyploidization and have to be taken into account if DNA measurements are performed for diagnostic purposes in lichen ruber planus lesions that are suspected of having malignant transformation.

DNA↗
PubMed1989

DNA grading of oral squamous carcinomas. A preliminary report.

The prognostic validity of the DNA-malignancy-grade (DNA-MG), ranging on a continuous scale from 0.00 to 3.00 was tested in a preliminary study on 7 patients with oral squamous cell carcinomas. Monolayer smears were prepared after a cell separation procedure from paraffin-embedded surgical tumor specimens. Feulgen staining was performed automatically in a modified Shandon staining machine. A TV image analysis system with an automatic microscope (TAS plus, Leitz, FRG) was used for DNA measurements. The DNA-MG revealed a strong correlation with the patients prognosis. 3 patients who died after having a tumor relapse (mean survival = 10 months) had DNA grades greater than 1.40, whereas patients who survived without having a tumor relapse (mean survival = 53 months) revealed DNA grades below 1.00. Additionally, the DNA-malignancy-grade was closely correlated with the histopathologic malignancy grades.

Adult↗
PubMed1988

[Development of the facial and periodontal approach to the maxillary sinus].

The nasal approach for operations of the maxillary sinus is becoming increasingly popular. The oral approach provides the best access for demonstration of the orbital floor, for ligation of the maxillary artery, for drainage of resistant rhinogenic sinusitis, and for removal of foreign bodies, tooth roots, dislocated teeth, odontogenic cysts and benign tumours of the maxillary sinus. Formerly the anterior wall of the maxillary sinus was removed, but nowadays procedures preserving the bone are chosen. The classical otorhinolaryngological incision lies in the limbus of the vestibule. Maxillofacial surgeons prefer an incision at the junction of the attached to the unattached gingiva because scars in the limbus of the vestibule create problems during later fitting of a denture. A follow-up of 40 patients shows that the gingival marginal incision causes no problems. This incision, introduced by Peter in 1930, is therefore preferred. The marginal incision does not leave any visible scars. It corresponds to an incision on the alveolar ridge in the edentulous patient.

Face↗