PubMed Health⌕ Search

Biomedical subjects

H Schliephake

Publications and source records attributed to H Schliephake.

90 records · Page 5Linked to original sources
PubMed1992

Restoration of the lateral sinus wall using a collagen type I membrane for guided tissue regeneration.

A collagen type I membrane prepared from bovine pericard was used to restore and thicken the lateral sinus wall after resection in 6 Göttingen minipigs. One rehydrated collagen type I membrane was placed on the intact sinus mucosa. A hydroxyapatite block was placed on this membrane and covered with a second membrane. After 6 months there was complete, bony regeneration in the space between the 2 membranes and thickening of the new bone plate compared to the untreated control side. This study shows that a collagen membrane can be applied for guided tissue regeneration.

Animals↗
PubMed1992

[Preoperative blood alcohol levels in patients hospitalized for prolonged surgical procedures].

Self medication using anxiolytic and relaxing agents prior to surgery is a common phenomen in many patients. In our prospective study of 356 patients undergoing prolonged surgical procedures (greater than 3 h), we evaluated the preoperative ethanol level of the blood using gas-chromatography. In 39 (10.9%) of 307 tumor patients ethanol could be detected in high concentrations, indicating the ingestion of disinfectants. Among our 49 orthognathic cases blood alcohol was found in 4 cases (8.2%). Since the minimum effective dose for ethanol ist 0.1 to 0.2 g/l, the patients' legal capacity when giving informed consent for surgery and anesthesia is to be questioned and the risks of analgosedation in outpatient must be considered.

Alcoholic Intoxication↗
PubMed1991

Bone replacement with porous hydroxyapatite blocks and titanium screw implants: an experimental study.

The aim of this experimental study was to examine whether porous hydroxyapatite (HA) blocks, fixed with titanium screw implants, could be used as a bone graft substitute. Twenty minipigs received coralline HA blocks for augmentation of surgically created defects in edentulous mandibles. Each block was fixed with two titanium screw implants. Two types of porous HA blocks that differed in pore diameter were used. A high rate of HA loss occurred in the group of animals that had received the HA block with small pore sizes, and fractures of the block occurred in the vicinity of the titanium implants in 12 of the remaining 13 cases. Histologic examination showed that the HA blocks with larger pore size were homogenously penetrated by bone that extended into the central pores and even incorporated the dislocated block fragments. The titanium implants were in close contact with the newly formed bone in these blocks. Little contact between bone and implants was seen in the HA blocks with the smaller pore size. The results indicate that, with improved mechanical properties, a combined augmentation with porous HA blocks and screw implants may be useful in primary reconstruction of bone defects.

Alveolar Ridge Augmentation↗
PubMed1991

Influence of pore dimensions on bone ingrowth into porous hydroxylapatite blocks used as bone graft substitutes. A histometric study.

The aim of the present study was to determine the influence of pore dimensions of porous hydroxylapatite (HA) blocks on bone ingrowth when used as interposed grafts in alveolar ridge bone defects. HA blocks with pore diameters of 150 microns and 260 microns were used. Ten animals received one implant each with small pore sizes, whilst in 10 other animals blocks with larger pore sizes were used. The blocks were examined histometrically and spatially reconstructed for determination of 3-dimensional distribution of bone ingrowth. In the group of implants with 150 microns pore diameter a high rate of implant loss occurred. The blocks with 260 microns pore diameter had 3 times more bone ingrowth compared with the 150 microns group with uniform distribution.

Animals↗
PubMed1991

Automated microdensitometric quantification of bone ingrowth into porous implants.

The aim of this study was to develop a technique of automated histometric quantification of bone ingrowth into porous implant bodies that minimizes errors of volume determination arising from the section thickness of histologic specimens. A theoretical and experimental deduction is provided for the calculation of implant and bone layer thicknesses from the grey levels of microradiographs made from thick-section specimens. The presented method allows rapid raising of large amounts of histometric data when a computer-aided video system is available. A histologic preparation of specimens that permits the spatial reconstruction of the examined implant volume and analysis of three-dimensional distribution of bone ingrowth is suggested.

Absorptiometry, Photon↗
PubMed1990

Influence of root development and root anatomy on the occurrence of periodontal damage during removal of third molars for transplantation: a histometric study.

The purpose of this study was to determine the influence of root development and root anatomy on surgically induced periodontal damage to third molars resulting from removal prior to transplantation. Thirty impacted third molars were removed by a careful technique, whereas another 30 were removed by the usual vestibular osteotomy and served as controls. Periodontal damage was histometrically evaluated on serial cross sections of the whole root and classified according to five categories describing the extent of damage to periodontal fibers, cementoblasts, and the cementum layer. The results showed more extensive damage to the periodontal membrane in the more mature stages of root development. A statistically significant influence of root anatomy on the occurrence of periodontal damage was not found.

Dental Cementum↗
PubMed1990

[Growth disorders following fractures of the midface in children].

12 patients who had suffered mid face fractures during their childhood were examined for skeletal deformities of the facial skull. The cephalometric data showed that neither the position nor the inclination of the maxilla were significantly different from normal anatomy. No correlation was found between the age, the severity of injuries and surgical treatment and resulting deformities.

Adolescent↗
PubMed1989

Periodontal damage to third molars prior to transplantation. A histometric study.

The aim of the present investigation was to determine the magnitude of surgically produced periodontal damage to third molars before transplantation. For this purpose, 30 impacted third molars were retrieved by a tissue-conserving surgical technique whereas 30 others were removed by a conventional technique. The surgically induced damage to the periodontal membrane showed a variable histological pattern. A significant reduction of the damage to desmodontal fibers and the cementum was achieved by using a special technique of removal.

Dental Cementum↗
PubMedDate not supplied

Osseointegration of titanium fixtures in onlay grafting procedures with autogenous bone and hydroxylapatite. An experimental histometric study.

The aim of the present study was to determine the degree of osseointegration of fixtures in different onlay grafting materials. Hydroxylapatite blocks of 2 different pore sizes and free monocortical bone grafts from the iliac crest were inserted in Göttingen minipigs and fixed with 2 titanium fixtures. The extent of the bone/implant interface area on the fixture surface was determined from histological specimens by morphometric measurements and related to the total thread surface of the fixtures. Fixtures inserted into bone grafts showed the most complete degree of osseointegration, whereas the smallest bone/implant interface area was found with fixtures inserted into those HA blocks with the smaller pore size. There was a significant decrease in the degree of osseointegration between the host bone site and the augmentation material only with the fixtures inserted into the HA blocks of smaller pore size.

Alveolar Ridge Augmentation↗
PubMedDate not supplied

Alveolar ridge repair using resorbable membranes and autogenous bone particles with simultaneous placement of implants: an experimental pilot study in dogs.

The aim of this experimental study was to evaluate the use of autogenous bone harvested during preparation of implant sites in combination with resorbable membranes for vertical ridge augmentation under 2 different defect site conditions. Combined vertical/horizontal alveolar bone defects were created by experimentally induced periodontal infections around all premolar teeth in the mandibles of 3 dogs (group 1). In another 3 dogs, fresh surgical defects were created after extraction of all premolar teeth in the mandibles (group 2). In all dogs, 2 implants were placed on each side of the mandible into the defect areas. One implant on each side of the mandible received augmentation with autogenous bone particles, and both implants on one side of the mandible were covered with polylactic acid membranes. After 5 months, the material was evaluated histologically. There was a small but significant increase in bone regeneration in the defects augmented with bone particles with and without membrane coverage in group 1. In group 2, no significant difference was seen between the controls and the augmented sites. The major limiting effect for bone regeneration appeared to be insufficient stability of the bone material to withstand the overlying soft tissue pressure. It was concluded that the placement of autogenous bone particles, either with or without membrane coverage, had little effect on the regeneration of peri-implant bone defects.

Absorbable Implants↗
PubMedDate not supplied

[Oromaxillofacial surgical treatment in aging patients].

The oral and maxillofacial surgical therapy of the elderly patient must include considerations of age-related physiological changes, both of inner organs and oral structures. Decreased hepatic and renal function may lead to delayed elimination of anaesthetic drugs and thereby make dose reductions necessary. Sclerosis or osteoporosis of jaw bones may render the surgical treatment of odontogenic diseases more difficult due to the increased fracture hazard. Painful ankylosis and rheumatic arthritis of the temporo-mandibular joint, tumors and fractures are common diseases of the elderly patient that a maxillofacial surgeon has to deal with. Furthermore, preprosthetic and reconstructive surgery is often required after jaw resections or severe atrophy. Due to the polypathy frequently present in elderly patients maxillofacial surgery requires particular indications, special surgical performance, and extensive postoperative care. By using all possible means, a satisfactory treatment can be achieved even in this age patients, whose quality of life can thus be improved.

Aged↗
PubMedDate not supplied

A review of material properties of biodegradable and bioresorbable polymers and devices for GTR and GBR applications.

Use of bioresorbable and biodegradable materials for guided tissue and guided bone regeneration is under intense investigation and is being tested in clinical trials. This study presents a basic overview of material properties of bioresorbable and biodegradable polymers and devices for guided tissue and guided bone regeneration treatment. Collagens and aliphatic polyesters, such as poly(glycolic acid), poly(lactic acid), and poly(epsilon-caprolactone), are discussed, as well as biocompatibility, mechanical properties, and sterilization.

Biocompatible Materials↗
PubMedDate not supplied

Vertical ridge augmentation using polylactic membranes in conjunction with immediate implants in periodontally compromised extraction sites: an experimental study in dogs.

Polylactic membranes were evaluated for vertical ridge augmentation around immediate implants in periodontally compromised extraction sites. Ligature-induced periodontitis was produced in 10 adult beagle dogs. The periodontium was allowed to heal for 6 weeks. All premolar teeth were extracted and three implants were placed immediately into the extraction sockets on either side of the mandible so that the polished cone extended above the alveolar bone level. On one side of the mandible, the implants were covered with a 0.2-mm-thick polylactic membrane (DL-lactide-co-trimethylene carbonate in a ratio of 7:3). Histologic and morphometric analyses performed after 3 and 5 months revealed that the membrane group did not exhibit significantly greater bone-implant contact than the controls. The occurrence of dehiscences correlated significantly with use of the membrane. Use of the membrane was associated with significantly less peri-implant bone height after 5 months. No remnants of the membrane material could be identified after 3 or 5 months, indicating rapid resorption during the first weeks of implantation. The tested membrane material did not fulfill the requirements of resorption kinetics and space maintenance for guided bone regeneration in vertical ridge augmentation.

Alveolar Process↗
PubMedDate not supplied

Mandibular onlay grafting using prefabricated bone grafts with primary implant placement: an experimental study in minipigs.

The aim of this experimental study was to evaluate the use of prefabricated autogenous bone grafts as onlay grafts to the mandible. Excess bone of 10 x 12 x 40 mm was produced inside blocks of pyrolyzed bovine bone under a polylactic membrane coverage on the outside of the mandible in 15 adult Göttingen minipigs. After 5 months, this bone was harvested and transferred to the premolar region of the mandibular body in 10 animals. Onlay grafts of mandibular bone were used as controls for the transplanted prefabricated grafts. All grafts were fixed by primary placement of one titanium implant each. Five animals served as ungrafted controls. Evaluation was performed after 3 months and 5 months, respectively. Two animals were lost to evaluation, and one scaffold became infected. Eleven of the remaining 12 scaffolds showed sufficient bone ingrowth for grafting. Three months after transplantation, bone volume of the prefabricated grafts was almost completely preserved, with only minimal resorption in the superficial pores of the scaffolds, while the control grafts exhibited partial resorption. The titanium implants, which had been placed at the time of only grafting, exhibited direct bone-implant contact. Five months after grafting, all titanium implants showed complete osseointegration, with direct bone-implant contact. The grafted bone exhibited a significant increase in bone density by appositional bone formation. The control grafts were nearly completely resorbed at that time.

Alveolar Bone Loss↗