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K L Gerlach

Publications and source records attributed to K L Gerlach.

At least 37 records · Page 2Linked to original sources
PubMed2000

[Resorbable polymers as osteosynthesis material].

The use of resorbable osteosynthesis materials spares the need for metallic implants and second operative procedures, which are often necessary, to remove the material. Appropriate substances are polymers and copolymers of glycolic and lactic acid. In a literature review, material characteristics, their degradation, and applications in animal experiments and clinical studies are presented. Particularly, the possible reasons of foreign body reactions occurring during the degradation period and material-related difficulties in practical use are discussed. It is evident that the use of low crystalline or amorphous polymers with in vivo long-lasting strength offers a secure and uncomplicated healing of fractures. Therefore, in future these substances will be an interesting alternative to common metallic osteosynthesis materials.

Animals↗
PubMed2000

[Incidence, risk factors and follow-up of sensation disorders after surgical wisdom tooth removal. Study of 1,106 cases].

A study was carried out to determine the risk of dysesthesia of the inferior alveolar and of the lingual nerve after molar surgery. A total of 1103 impacted lower wisdom teeth and 3 impacted lower second molars were removed in 687 patients, all of whom with unaltered sensibility preoperatively. Clinical, radiological, and surgical factors of each case were recorded. Postoperative disturbances in the sensibility of the lip and tongue were evaluated by neurological examination. Follow-up was carried out for a maximum of 35 weeks. Dysesthesia of the inferior alveolar nerve occurred with an incidence of 3.57%. The lingual nerve was injured in 2.1% of patients. Most of the initially reported alterations in sensation resolved within the follow-up period. Dysesthesia of the inferior alveolar nerve persisted in 0.91%, and of the lingual nerve in 0.37%. However, the extent of the prolonged impairment was slight in general. The effect of the documented factors on the incidence of dysesthesia was analyzed. For the inferior alveolar nerve, analysis revealed significant effects in older patients, for completely developed roots, for deeply impacted teeth, in the radiological relationship of the roots and the inferior alveolar canal, for difficult surgery, and for intraoperative exposure of the nerve. The surgeon and the anesthesia had a significant influence on lingual dysesthesia.

Adolescent↗
PubMed2000

Failed closed reduction of a bifocal mandibular fracture because of dislocation of the mandibular ramus behind the styloid: case report.

We present an unusual dislocation of the mandibular ramus after a low condylar fracture associated with a fracture of the opposite body of mandible. As closed reduction failed, both fracture sites were exposed. The mandibular ramus was dislocated behind the styloid process, which was not shown on the preoperative radiographs. The intermediate fragment was freed and the fractures treated by miniplate osteosynthesis. The patient made an uneventful recovery with no residual deformity.

Fracture Fixation↗
PubMed1999

Secretion of TFF-peptides by human salivary glands.

TFF-peptides (formerly P-domain peptides, trefoil factors) are typical secretory products of mucin-producing cells and seem to influence the rheological properties of mucous gels. Here, localization studies of TFF-peptides in human salivary glands are presented. Expression studies (polymerase chain reaction) revealed mainly TFF3 transcripts in submandibular and sublingual glands and trace amounts in parotid glands. Only low levels of expression of TFF1 could be monitored in submandibular and sublingual glands, and TFF2 transcripts were hardly detectable in all three major salivary glands. This result was partly confirmed by Western blot analysis, which only detected TFF3 in submandibular glands, but not in sublingual and parotid glands. TFF3 was also shown to be a constituent of human saliva. Immunofluorescence localized TFF3 solely in the secretory granules of serous cells of submandibular glands but not in mucous cells. This localization is remarkably similar to that of the unique low-molecular-weight mucin MUC7, which interacts with a number of oral microorganisms.

Blotting, Western↗
PubMed1999

Clinical applications of drill free screws in maxillofacial surgery.

Drill free screws are newly designed osteosynthesis screws with specially formed tips and cutting flutes, which act like a cork-screw and can be inserted into bone without predrilling. A prospective study on 82 patients was performed in order to investigate the efficiency of mini- and micro-drill free screws (DFS) in clinical use and to find out areas in maxillofacial traumatology and orthognathic surgery, where the application of this new type of screw may be recommended. Thirty-eight Le-Fort-osteotomies, 23 central and lateral midfacial fractures and 21 fractures of the mandible were fixed using the Champy titanium micro/miniplate system and in total 518 center-drive titanium micro-DFS (1.5 mm) and 392 center-drive titanium mini-DFS (2 mm) with lengths between 4 and 7 mm. The results showed that the grip of micro- and mini-DFS was sufficient for the fixation of bone fragments in the central and lateral midface and in the mandibular area. The insertion of DFS was simple and is recommended in the area of the central midface; the insertion of the screws was difficult, but possible in the anterior mandible and in the lateral midface. The application of DFS in the mandibular angle region is not recommended.

Adolescent↗
PubMed1998

[Effect of the diameter of various bore holes on retention of osteosynthesis screws].

The standard drill size for most osteosynthesis screws is about 75% of the screw's external diameter. When screws are inserted in thick cortical bone, a small pilot hole size can result in high torsional stress, leading to screw fracturing. The aim of this study was to enlarge the drill size up to a critical pilot hole size, exceeding of which leads to a rapid decrease of the screw's holding power. Titanium screws of diameter 1.5 and 2 mm were inserted in discs of PVC, wood and porcine mandibular bone with different thickness between 2 to 4 mm, using pilot hole sizes of 66-95% of the screw's external diameter. The maximum torque was recorded and pull-out tests were performed. Ten trials were conducted for each screw-pilot hole size-material combination, yielding a total of 1560 tests. A multiphase regression analysis was performed to calculate the critical pilot hole size (CPHS). In torque measurements, the CPHS of microscrews were between 83% and 85% of screw outer diameter (SOD) and the CPHS of miniscrews were between 80% and 90% of SOD. In pull-out analysis the CPHS of microscrews were between 83% and 89% of SOD and the CPHS of miniscrews were between 79% and 91% of SOD. The CPHS was thus found to be around 85% of the screw's external diameter. Up to this critical point the pilot hole size may be increased without affecting the holding power of the screws.

Animals↗
PubMed1998

Drill Free Screws: a new form of osteosynthesis screw.

Although the application of self-tapping and non self-tapping screws is virtually universal in cranio-maxillofacial surgery, the inevitable, time consuming procedure of drilling a pilot hole has some potential disadvantages, such as damage to nerves, tooth roots or tooth germs, thermal necrosis of the bone and drill bit breakage. Drill Free Screws (DFS) are a recently developed type of osteosynthesis screws, having a tip like a cork screw and specially formed cutting flutes which enable insertion of the screws without drilling. DFS 1.5 and 2 mm were inserted into discs of wood, polyvinylchloride (PVC) and porcine mandibular bone of varying thicknesses between 2 and 4 mm. The values of insertion torque and maximum torque were recorded using an electric torque tester. Thereafter, the screws were inserted with a fixed torque and uniaxial pull out tests were performed. In comparison with this, the same procedure was performed using 1.5 and 2 mm self-tapping titanium screws. Ten trials for each screw-material-combination were conducted to determine insertion torque, maximum torque and pull out analysis. The results showed that the holding power of DFS lay between 70 and 104% of the holding power of self-tapping titanium screws; only in PVC was the difference more than 15%.

Animals↗
PubMed1998

Influence of different pilot hole sizes on torque measurements and pullout analysis of osteosynthesis screws.

When screws are inserted in thick cortical bone, a small pilot hole size, corresponding to the core diameter of the screw, can result in high torsional stress, leading to screw fracture. The aim of this study was to enlarge the drill size up to a critical pilot hole size (CPHS) which, if exceeded, means a rapid decrease in the screw holding power. 1.5 and 2 mm titanium screws were inserted in discs of polyvinylchloride (PVC), wood and porcine mandibular bone with thicknesses differing between 2 to 4 mm, using an increasing pilot hole size between 66% and 95% of the screw external diameter. Torque measurements and pullout tests were performed and the CPHS was calculated. In torque measurements, the CPHS of microscrews ranged between 83% and 85% of the screw external diameter (SED). The CPHS of miniscrews lay between 80% and 90% of SED. In pullout analysis, the CPHS of microscrews ranged between 83% and 89% of SED; the CPHS of miniscrews lay between 79% and 91% of SED. The mean of the CPHS was calculated to be approximately 85% of the SED. Up to this critical point, the pilot hole size may be increased without affecting the holding power of the screws.

Animals↗
PubMed1995

Temporomandibular joint morphology in children after treatment of condylar fractures with functional appliance therapy: a follow-up study us computed tomography.

The consequences of treating fractures of the temporomandibular joint in children by means of functional appliance therapy remain controversial. In this retrospective study we evaluated the temporomandibular joint morphology of 19 children and adolescents who had sustained a total of 21 condylar fractures between three and nine years previously and who had been treated in this way. Restoration of function was assessed clinically by measurement of mandibular movements, and palpation and auscultation of the joint. Spiral CT was used for the radiological examination with 2D and 3D reconstructions. Eleven patients with 13 fractures of different types showed restoration of normal function with favourable remodelling. The remaining eight patients had only good function with a deformed condyle and significant asymmetry in condylar angle and length of the condylar neck. Four of these cases had also developed bony spurs, neo-arthrosis and a bifid condyle. On the basis of these results, spiral CT imaging appears to be a valuable diagnostic aid in cases of condyle fractures where severe morphological changes are not recognized in earlier conventional X-ray examinations. The authors recommend a quantitative and qualitative analysis of the temporomandibular joint in order to encourage patients' compliance and, in cases of poor cooperation, to extend the treatment time.

Adolescent↗
PubMed1995

[Long-term roentgenologic follow-up of asymptomatic impacted wisdom teeth in former orthodontic patients].

Long-term follow-up of orthopantomographs of 251 adults orthodontically treated former patients showed 113 clinically asymptomatic impacted 3rd molars in 58 patients. Radiographic assessment revealed contact of impacted 3rd molars with the 2nd molars, resorption of upper and lower 2nd molars, reduced bone height on the distal side of the maxillary and mandibular 2nd molars, as well as pathologically widened pericoronal spaces of the upper and lower 3rd molars. The comparison of the sagittal 3rd molar position in 52 impacted teeth revealed a sagittal change in all 3rd molars from post-treatment to follow-up: maxillary and mandibular 3rd molars had rotated to a more upright position and showed an increase in mesio- or distoangulation or a change of axial inclination. The lack of predicting factors such as age, period of impaction, extent of space deficiency, developmental stage, level of eruption, and bone conditions leads the authors to recommend that former orthodontic patients be recalled at regular intervals for assessment of changes in the condition and position of erupting or impacted 3rd molars.

Adult↗
PubMed1994

CT analysis of temporomandibular joint state in children 5 years after functional treatment of condylar fractures.

This retrospective study assessed the temporomandibular joint (TMJ) state of children who had suffered unilateral condylar fractures at least 5 years before and had been treated by functional orthopedic methods alone. The sample group were examined radiologically by computed tomography (CT) spiral scans which were reformatted to two-dimensional (2-D) images in different anatomic planes and to 3-D reconstructions in various projections. Although the seven patients who formed the sample group showed good-to-excellent functional results, the quantitative and qualitative analysis of the scans revealed alterations of size, shape, bony remodeling, and position of the condyle on the fracture side, as well as adaptive changes of the temporal component of the joint. We recommend spiral CT for assessment of TMJ disorders and fractures of the condyle at the time of injury and for follow-up assessment.

Bone Remodeling↗
PubMed1994

A long-term, follow-up, radiographic evaluation of asymptomatic impacted third molars in orthodontically treated patients.

Long-term follow-up orthopantomographs of 251 adult orthodontically treated former patients showed 113 clinically asymptomatic impacted third molars in 58 patients. Radiographic assessment revealed contact of impacted third molars with the second molars, resorption of maxillary and mandibular second molars, as well as pathologically widened pericoronal spaces of the maxillary and mandibular third molars. The comparison of the sagittal third molar position in 52 impacted teeth revealed a sagittal change in all third molars from post-treatment to follow-up: maxillary and mandibular third molars had rotated to a more upright position and showed an increase in mesio- or distoangulation or a change of axial inclination. The lack of predicting factors such as age, period of impaction, extent of space deficiency, developmental stage, level of eruption, and bone conditions leads the authors to recommend that former orthodontic patients be recalled at regular intervals for assessment of changes in the condition and position of erupting or impacted third molars.

Adult↗
PubMed1994

p53 and PCNA expression in malignant melanomas of the head and neck.

Mutation in the p53 tumor suppressor gene is the most common genetic alteration in human cancer. As in mutant p53 the protein is stabilised and the half-life is extended, it becomes detectable by immunohistological staining. p53 immunoreactivity thus seems to be a potential biomarker for the assessment of the oncogenic potential of malignant melanomas. In 103 tissue sections of primary and metastatic malignant melanomas of the head and neck detectable levels of p53 were only found in 3 of the primary tumors and in none of the metastases. At the same time the proliferation status of the malignant melanoma lesions was determined using the cell cycle specific antibody PCNA. 55 primary and metastatic tumors were stained with a PCNA-MAb to determine the proliferation activity of the tumors. The results of our immunohistochemical investigation suggest that immunoreactivity of p53 cannot be used to determine the malignant potential of melanomas in the head and neck. PCNA staining showed that the majority of the tumors and metastases were proliferating rapidly.

Antibodies, Monoclonal↗
PubMed1993

In-vivo and clinical evaluations of poly(L-lactide) plates and screws for use in maxillofacial traumatology.

The possible application of biodegradable osteosynthesis material presents many advantages over conventional metallic devices. This study was concerned with the in-vivo evaluation of poly(L-lactide) with different molecular weights, in particular in regard to their mechanical strength, changes of molecular weight and their tissue response. It was found that poly(L-lactide) has acceptable mechanical strength for use in maxillofacial traumatology. In another trial, mandibular fractures of 12 dogs were successfully stabilized with resorbable plates and screws made of this polymer. Finally, the results of a pilot study of its clinical application in the treatment of zygomatic fractures have been presented.

Animals↗
PubMed1993

Cysts associated with long-standing impacted third molars.

Three patients are described in whom large cysts developed around third molars that had purposely been left in place. The cases presented emphasize the need for an adequate prospective study to evaluate the long-term morbidity of asymptomatic third molars that are left in place.

Adult↗