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Biomedical subjects

D Weingart

Publications and source records attributed to D Weingart.

At least 19 recordsLinked to original sources
PubMed2001

[Peri-osseous intracranial translocation of titanium osteosynthesis plates and screws after fronto-orbital advancement].

BACKGROUND: Perossoeus intracranial translocation or passive intracranial transmission of titanium osteosynthesis plates and screws in the growing skull following surgical craniosynostosis corrections, also referred to as the PIT effect, has been described in the literature since 1995. It is a phenomenon which has not received due attention until recently and is explained by appositional and resorptional remodeling processes in the growing skull. CASE REPORT AND DISCUSSION: An impressive case of the PIT effect with a total intracranial dislocation of titanium plates and screws is used to demonstrate the problems associated with this phenomenon and to discuss the few clinical case reports in the English-language literature. The obvious advantages of a resorbable material are pointed out; however, it is still uncertain as to whether the resorption process is fast enough to avoid the PIT effect if used clinically.

Bone Plates↗
PubMed2001

[Resorbable osteosynthesis material in craniosynostosis].

BACKGROUND: The results of using resorbable plates and screws (82% polylactic acid and 18% polyglycolic acid) in craniofacial surgery for the correction of craniosynostosis after more than 4 years of experience are presented. Special attention is focussed on the degree of stability and the clinical tissue response to the material employed to answer the question of whether the material is an adequate alternative to titanium. METHODS: Thirty patients who had been treated with this method for craniosynostoses were examined at regular intervals regarding the shape and stability of the forehead region, visibility and palpability of the plates, and tissue reactions. RESULTS: The technical handling of the osteosynthesis material proved to be simple and reliable. In one case the bone was not strong enough for the screw pitch. After an observation period of a maximum of 4 years and 1 month, the fixations were stable with no signs of adverse reactions. DISCUSSION: If the long-term results remain favorable, we consider the use of resorbable material a promising method for the stabilization of segments in craniofacial surgery in children.

Absorption↗
PubMed2001

[Mid-face distraction after LeFort III osteotomy in craniofacial dysmorphism].

BACKGROUND: The success of LeFort III-osteotomy with concurrent advancement of the midface in cases of severe, midfacial hypoplasia is limited by the soft covering tissue of the facial skeleton. There appear to be significant advantages in using distraction osteogenesis of the midface after surgery. CASE REPORT: We discuss the use of an extraoral distraction device after the osteotomy of a 10-year-old girl with Crouzon's disease. and the use of an internal device for a 6-year-old boy with severe midface hypoplasia following Apert's syndrome. RESULTS: In both patients a significant improvement of function, as well as harmonisation of the facial proportions, could be observed and the preoperatively planned distances of midface advancement of 18 and 15 mm respectively could be achieved. DISCUSSION: Distraction osteogenesis is an established procedure for the treatment of mandibular hypoplasia but few reports dealing with complex midface distraction are available outside of the specialist English language literature. We report on both external and internal distraction techniques with which good functional and aesthetic results were achieved.

Acrocephalosyndactylia↗
PubMed2000

[Hemostatic wound management in marcumar patients. Collagen fleece vs. tranexamic acid].

A total of 124 patients on oral anticoagulation therapy with coumarin were treated by orosurgical procedures and entered into a study to determine the hemostatic efficiency of different methods. The therapeutic anticoagulation level was determined in accordance with the recommendations of the American Heart Association (low risk: 2.0 < INR < 3.0; high risk: 2.5 < INR < 3.5) and maintained during treatment. In one group, the alveoli were treated with collagen, in a second group a mouthrinse regime with tranexamic acid was implemented. Twenty-three patients had to be excluded because anticoagulation levels differed from the recommended values. The group treated with collagen included 31 patients, the group with tranexamic acid mouthwashes, 32 patients. A third group was analyzed in which a controlled change in the anticoagulation level had been performed and all treated alveoli had been covered by mucosal flaps (n = 38); they were compared to the other two groups. The surgical proceedings were outlined precisely. Patients treated with collagen had a bleeding rate of 19%, patients with tranexamic acid mouthwash 6%, and those treated with mucosal flaps 40%. The data were not suited for statistical evaluation, they were objected to a descriptive analysis: the confidence intervals were determined by tables for binomial distributions. These did confirm the difference in the frequency of bleeding for the tranexamic acid and mucosal flap groups.

Adult↗
PubMed2000

Basic surgical principles with ITI implants.

The basic surgical principles governing the placement of ITI implants are based on research-oriented developments in harmony with evidence-based and outcome-oriented clinical procedures. In the past 15 years, the range of implant indications has been significantly widened, and partially edentulous patients clearly represent the majority of patients seeking treatment with dental implants today. An important aspect of the successful rehabilitation of patients with ITI implants is the careful selection of implant candidates with respect to systemic and local risk factors. These factors are presented based on current knowledge. Today, solid-screw implants in various screw dimensions and neck configurations comprise the ITI Dental Implant System. These different implant types are necessary to handle the full range of implant indications, in particular in partially edentulous patients. The main clinical factors are presented for the selection of the appropriate implant type, length and diameter. These implants are utilized both in a non-submerged and in a submerged approach. The main goal of surgical therapy is low trauma and the least demanding surgical procedure for patient and clinician to optimize the cost-effectiveness of implant therapy. Hence, a non-submerged approach is preferred in all sites without esthetic priority, such as in fully edentulous patients or in posterior sites of partially edentulous patients. These indications clearly represent the majority of implant patients. In esthetic sites, a submerged approach is utilized to satisfy the specific esthetic demands. The possibility to successfully utilize short implants (6 and 8 mm) and a reduced healing period of 3 months are further advantages of ITI implants due to favorable properties of the rough TPS surface. With the introduction of the microrough SLA surface, a reduction of the healing period to 6 weeks facilitates further progress towards simplification of implant therapy. In summary, the ITI Dental Implant System represents a scientifically well-documented, complete implant system for the treatment of fully and partially edentulous patients, offering straightforward surgical concepts based on predictable treatment outcome and excellent cost-effectiveness.

Antibiotic Prophylaxis↗
PubMed2000

Treatment of fully edentulous patients with ITI implants.

The use of ITI implants for rehabilitation of the edentulous patient has shown predictable results not only in the standard sites but also in cases of advanced alveolar ridge atrophy. Preoperative analysis, including clinical and radiological evaluation, implant selection, and determination of implant number and distribution in the edentulous maxilla and mandible, is described in this article. The surgical procedures used in standard sites are presented, the benefits of a nonsubmerged surgical approach in these cases are emphasized, and a protocol for postoperative management is recommended. Augmentation procedures in advanced osseointegration surgery call for submerged ITI implants when a simultaneous approach is chosen. Several types of advanced implant surgery that can be used are described, including membrane technique, sinus lift procedures, vertical ridge augmentation with iliac bone grafts, and correction of sagittal jaw relationship.

Alveolar Ridge Augmentation↗
PubMed2000

Oral findings in three different groups of immunocompromised patients.

The objective of this study was to determine the frequency of oral, dental and periodontal findings in three different groups of immunocompromised patients and in a healthy control group, to evaluate whether there is a correlation between manifestations of disease and immunologic parameters. The survey included 46 patients with a diagnosis of systemic lupus erythematosus, 48 heart transplant recipients, and 53 adult patients suffering from acute leukemias. Fifty matched healthy subjects were used as a control group. Each patient had to answer questions on medical and dental health and underwent a thorough oral, dental and serological investigation. Oral mucosal lesions were found in nearly half of all immunocompromised patients (49.6%), but in only 26% of control patients. No significant associations were found between different types of oral lesions and the underlying cause of immunosuppression. Leukemia patients showed age-unrelated higher scores in periodontal indices (P<0.05). Laboratory parameters failed to be significant in the assessment of oral health.

Adult↗
PubMed1999

Heart transplants--assessment of dental procedures.

The object of this study was to evaluate the effects of dental foci on survival rates and rejection episodes in heart transplant recipients. Therefore, in a retrospective longitudinal study we studied 74 heart transplant recipients at the Department of Maxillofacial Surgery and Department of Thoracic and Cardiovascular Surgery, University of Münster. Study patients were divided into groups: those in which dental foci had been verified (n = 31) and those without dental foci (n = 43). Statistical analysis was performed using the chi-square test, Kaplan-Meier life table analysis, and the log-rank test. Before heart transplantation, patients were screened clinically and radiographically to determine the extent of dental foci. Postoperatively, patients were evaluated dentally and medically to identify the impact of dental foci on the incidence of systemic and oral infections, frequency and severity of rejection episodes, mortality, and complications arising during dental treatment. By comparing the mortality, infection and rejection rates in the various groups no statistically significant differences (P > 0.05) were found between patients. Despite immunosuppression, extended inflammatory processes such as abscess formation or viral stomatitis were not found in the oral cavity. We therefore suggest that patients suffering from the symptoms of severe heart failure need not be subjected to rigorous preoperative dental treatment.

Bacteremia↗
PubMed1999

[Preliminary results of the use of resorbable plates and screws in craniofacial surgery].

In ten patients with craniosynostoses resorbable plates and screws (Lactosorb) consisting of poly-L-lactic acid (82%) and poly-glycolic acid (18%) were used to stabilize the segments after frontoorbital advancement. As our experience increased, an exact adaptation of the plates and simple handling proved to be possible. The plates were stable enough to retain a favorable functional and aesthetic result after redraping the soft tissue envelope. In one patient with Chotzen's syndrome the intended use of the resorbable material was abandoned: the thin osseous structures did not offer enough primary stability to the high pitch of the screws. During an observation period of up to 21 months no infection, exposure, instability or dislocation was observed. The clinical use of the resorbable material in frontoorbital advancement proved to be a stable method of segment fixation if the bone was of sufficient thickness. These promising preliminary results will have to observed in a larger group and over a longer period of time.

Absorbable Implants↗
PubMed1999

Use of a mandibular fracture score to predict the development of complications.

PURPOSE: Mandibular fractures are common facial injuries. Classifications are diverse and sometimes correlated with specific treatment modalities. Osteosynthesis using plate and screws is the standard method of fracture treatment. To evaluate the outcome of such fracture management in our clinic, we developed a numeric scoring system for mandibular fractures and investigated the relationship between the scoring of the fracture being treated and the incidence of complications after surgical treatment. PATIENTS AND METHODS: Seventy-six adult patients treated over a 2-year period were evaluated, and the fractures were classified using the mandibular trauma score. This score was based on clinical and radiologic evaluation of each fracture line and ranks from 0 to 15 points. Osteosynthesis was performed using the AO plate systems. Patients were followed-up postoperatively for the presence of complications. RESULTS: During the 2-year period, 76 patients with 134 fractures underwent plate osteosynthesis. Fracture scoring indicated a homogeneous distribution between uncomplicated and severe fractures. The incidence of complications increased with the fracture severity, assessed by the fracture score index. Severe fractures showed fewer complications when treated with a rigid plate system, whereas low-score fractures showed better results when treated with less rigid systems. CONCLUSIONS: The numeric scoring system for mandibular fractures allows an objective and standardized assessment of the degree of severity of a fracture and may facilitate decisions about the use of specific treatment modalities.

Adult↗
PubMed1998

[Surgical correction of the sagittal shift of the jaws in severe alveolar atrophy].

A method for treatment of sagittal discrepancy in edentulous patients is described, which includes simultaneous maxillary repositioning by means of a Le Fort I osteotomy and placement of endosseous implants. The technique of mandibular setback using the sagittal osteotomy of the mandible according to Obwegeser-Dal Pont's method and placement of implants in patients with extreme class III relationships is also presented. We outline the importance of thorough diagnosis, model surgery and its transfer at the time of the operation. The study of 12 consecutively treated patients with a follow up of 4.2 years showed functionally and esthetically good results after combined surgical and implantological treatment.

Alveolar Bone Loss↗
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↗
PubMed1996

[Differential indications for various therapeutic osteosynthesis concepts in mandibular fractures].

The surgical treatment of different types of mandibular fractures requires complex consideration. It can be realised not by the application of only one treatment concept, e.g. miniplates or rigid osteosynthesis, but a differentiated indication of every stability system depending on the individual requirements in each case. Basing on the results of clinical studies the contemporary concept applied at Münster in treatment of mandibular fractures is presented.

Bone Plates↗
PubMed1994

Titanium deposition in regional lymph nodes after insertion of titanium screw implants in maxillofacial region.

The deposition of titanium in regional lymph nodes was studied after insertion of endosseous, plasma-spray-coated titanium screw implants in a total of 19 beagle dogs. Five additional animals with no implants served as the control group. After killing the animals 9 months postoperatively, the regional lymph nodes were carefully excised, and samples were prepared for histologic examination. Other samples were used to identify foreign particles by energy-dispersive x-ray analysis and for measurement of the titanium concentration in the tissue by flameless atomic absorption spectroscopy. Very fine foreign-body particles could be seen in the histologic sections, and they were identified as titanium by energy-dispersive x-ray analysis. The atomic absorption analysis for titanium revealed a significantly higher concentration in the group with implants. The presence of very fine, poorly attached particles on the plasma-sprayed titanium surface suggests that these particles may be mechanically dislodged from the surface on insertion of the implants. This suggests that the fine particles may be transported by phagocytes to the regional lymph nodes, where they could be found without any signs of inflammation or foreign-body reaction.

Animals↗
PubMed1994

ITI implants in combination with bone grafts: design and biomechanical aspects.

In this article we describe the implantation of ITI implants in combination with bone grafts. Two different cases were considered: the augmentation of an atrophic maxilla or mandible where the transplant was fixed by means of ITI implants and the implantation into free transplants fixed by means of the THORP reconstruction plate system. These indications require 2-stage procedures with submerged implants and transplants during the healing period. For this new applications, standard ITI implants were combined with specially developed new transgingival units of high manufacturing precision. The new design resulted in a maximum tightening moment of 4.0 N.m versus 1.25 N.m achievable with a conventional 2-mm screw. Dynamic testing showed that, for the range of tightening moments of 0.25 N.m up to 1.0 N.m, the loosening moment after 2,000,000 cycles remained approximately 10% above the tightening moment. For the clinical application a tightening moment of 0.35-0.5 N.m is recommended. The special design and the high precision of the extension parts results in a tight adaptation between the primary implant and the extension parts, which may be important for microbiological reasons.

Alveolar Ridge Augmentation↗
PubMed1993

Strip ostectomy and radical ostectomy in the treatment of craniosynostosis. An experimental animal study.

In an experimental animal study using rabbits, growth phenomena were simulated which are comparable to craniosynostosis in humans. The radiological and histological findings after surgical management of these artificial craniosynostosis by means of strip ostectomy or radical ostectomy were compared with the findings obtained in control animals. Following strip ostectomy, bone defects were rapidly filled by the formation of suture-like structures. After radical ostectomy, structures consisting of connective tissue dispersed among islands of ossification were preserved over a considerable period of time, making it possible for the calvarium to adapt to the fast-growing brain. In contrast to strip ostectomy, after radical ostectomy growth of both the neurocranium and the viscerocranium, as well as the total sagittal growth of the skull, were almost identical to the corresponding growth in the control animals.

Animals↗