Biomedical subjects

T Weischer

Publications and source records attributed to T Weischer.

13 recordsLinked to original sources

PubMed1999

[Prosthetic-implantology defect treatment concept for oral rehabilitation of the mandibular area after tumor treatment].

Between 1988 and 1997, tumor resection was carried out in 18 irradiated patients group 1: 36-72 Gy. 83 implants) and 22 nonirradiated patients (group 2: 92 implants) in the mandible and floor of the mouth, and these patients subsequently underwent mandibular endosseous implant rehabilitation. A total of 23 patients were treated with exclusively implant-supported prostheses, and 16 with implant tissue-supported constructions. Between 1988 and 1991, group 1 and 2 patients received implant tissue-supported prostheses (using two to four implants). Due to prosthesis-related pressure lesions, the strategy has now been changed. Since 1992, group 1 patients have received exclusively implant-supported prostheses (using five to six implants), while group 2 patients have received implant tissue-supported constructions (using four implants). Special criteria for the success of implant-supported maxillofacial prosthetics were drawn up. With an average follow-up period of 37 months 160 fixtures (91%) were clinically osseointegrated. Both types of restoration provided sufficient oral rehabilitation. However, only completely implant-supported prostheses avoided soft tissue ulcers. The overall success rate was about 77% after 7 years in group 1 and about 87% after 9 years in group 2. With regard to implants placed after strategy change, the 5-year success rate was approximately 86% (group 1) and 94% (group 2). In irradiated patients, an exclusively implant-supported prosthesis without any mucosal contact (thus avoiding soft tissue ulcers with a potential to develop osteoradionecrosis) should therefore be fabricated. Implant tissue-supported restoration is also possible in nonirradiated oral cancer patients.

Adult↗

PubMed1998

Characterization of the periodontal microflora by the fatty acid profile of the broth-grown microbial population.

The applicability of fatty acid analysis to the characterization of periodontal microflora was investigated using gas-liquid chromatography (GLC) and the software of the Sherlock Microbial Identification System (MIS) from MIDI Inc. Sulcus fluid was collected with paper points and anaerobically cultured in broth at 35 degrees C for four days. The broth-grown microbial population was extracted and the fatty acid methyl esters (FAME) were separated by GLC. The investigation of 67 specimens from asymptomatic sulci and of 32 specimens from inflamed sulci showed that the patterns of FAME profiles, the clustering of FAME profiles by computerized 2-D plot procedure, and the determination of the peak area index (PAI) of the FAME profiles differentiate between normal and pathological sulcus flora. Comparison of the clinical sulcus rating and the FAME data indicated that a pathological FAME profile may precede manifest periodontitis, and the normalization of the FAME profile may precede healing. It is concluded that the FAME analysis of sulcus fluid is a diagnostic aid for periodontological surveillance, for the initiation of preventive treatment of periodontitis, and for controlling the antimicrobial efficiency of therapeutic measures.

Anaerobiosis↗

PubMed1997

[Primary soft tissue coverage and specific after-care of endosseous implants in pre-irradiated orbits].

After orbital exenteration and high- dose irradiation (60 Gy on average), 17 endosseous implants were placed periorbitally in 5 patients. No hyperbaric oxygen therapy was performed. All implants were primarily covered with regional or free flaps. After second-stage surgery and aesthetic rehabilitation with an external maxillofacial prosthesis, the pocket depth and implant stability (periotest) were checked, an occipitonasomental radiograph was taken and the soft tissue assessed in short recall intervals. When the implant was uncovered, osseointegration was stable. Within a follow-up period of 35 months, no fixation had failed. In two patients, peri-implant inflammation (microbiologically confirmed Staphylococcus aureus) occurred, which was clinically only determined by soft tissue oedema and rubor. The results demonstrate primary soft tissue covering as essential for non-irritating implant osseointegration in the irradiated orbita. In extraoral implants the clinical estimation of the peri-implant soft tissue, including a microbiological examination, is required for early detection of peri-implant inflammation in order to avoid secondary implant failure. In contrast, periotest and pocket depth are not relevant in recognizing an ensuing peri-implant inflammation.

Adult↗

PubMed1997

[Early detection of threatened implant loss in tumor patients].

After resection of an oropharyngeal tumor, 157 dental implants were placed in 17 irradiated (44 Gy on average) and 20 non-irradiated patients. Within a control period of 37 months, 15 implants had failed. The reason for implant failure was analyzed, whereby indicative parameters were revealed. Eleven implants in four irradiated and one non-irradiated oral cancer patients showed no primary osseointegration during the healing period because of mandible fracture, overloading or for unknown reasons. Four implants in one irradiated and three non-irradiated oral-cancer patients were lost subsequently on average 39 months after second-stage surgery due to biomechanical overloading or bacterial infection. No osteoradionecrosis development due to implant failure was observed in irradiated patients. In all cases, peri-implant pocket depth, implant stability and peri-implant bone resorption increased before definitive implant failure. Therefore, these findings seem to be useful as indicative parameters in the prediction of implant failure.

Adult↗

PubMed1997

[Suppurative abscess-forming mediastinitis after tooth extraction. Consequences for therapeutic approach].

Purulent mediastinitis is a rare but serious complication of a descending odontogenic infection with a high mortality. Diagnosis is difficult and frequently delayed. Physical examination is often nondiagnostic, but may include pronounced edema of the neck and chest. CT scan is the single most important tool for early diagnosis. The treatment is always is surgical, in combination with an extremely high dose of combined antibiotics. Ultimately, we only could save our patient with this therapy.

Abscess↗

PubMed1995

[Dental treatment before radiotherapy of carcinoma of the mouth floor].

Two collectives of patients who required radiation therapy were built. In order to determine the adequate occasion and extension of surgical teeth restoration in dependence on radiation therapy, both collectives were compared. The first group implicated 21 manifest ORN. The triggers of these ORN were evaluated. In the second collective the ORN occurrence after 225 generous surgical teeth restorations before radiation therapy were prospectively fixed and analysed. In comparison of both collectives the concept of generous removing of all potential dentogene inflammations before radiation therapy was successful in prevention of the septic ORN.

Humans↗

PubMed1994

No cultural detection of Helicobacter pylori in dental plaque.

Helicobacter pylori causes human type B gastritis and is involved in the etiology of peptic ulcer disease. The routes of transmission of H. pylori are still unclear. The microorganism may be transmitted orally, since H. pylori has been detected in dental plaques. To confirm the hypothesis that dental plaques are a reservoir of H. pylori, 100 dental plaque specimens from 55 dental surgery patients were incubated on one nonselective and up to four selective agar media for the detection of H. pylori. In addition, urease activity of the plaque material was tested, and the gingival status of the patients was assessed. H. pylori was not cultivated from any of the specimens investigated. Plaque material from 12 patients with moderate and severe gingivitis showed urease activity. The results do not confirm the hypothesis that dental plaques are a relevant reservoir of viable H. pylori cells. However, non-cultivatable forms of H. pylori may survive in dental plaques. Urea cleaving activity of dental plaque may be a marker of gingival inflammation.

Adolescent↗

PubMedDate not supplied

Ten-year experience in oral implant rehabilitation of cancer patients: treatment concept and proposed criteria for success.

Between 1988 and 1997, 18 irradiated patients (group 1, 83 implants) and 22 nonirradiated patients (group 2, 92 implants) received resection of the cancer-involved mandible and floor of the mouth and subsequently underwent mandibular rehabilitation with endosseous implants. Implant-supported prostheses were placed in 26 patients, while 13 patients received implant-tissue-supported prostheses. Between 1988 and 1991, patients were restored with implant-tissue-supported prostheses (based on 2 to 4 implants). This strategy was later changed because of the development of denture-related lesions. Since 1992, group 1 patients have been restored exclusively with implant-supported prostheses on 5 to 6 implants; group 2 patients have been rehabilitated alternatively with implant-tissue-supported prostheses on 4 implants. Special criteria for determining the success of implant-supported maxillofacial prostheses were developed. With a mean follow-up period of 37 months, 160 implants (91%) were clinically osseointegrated. Both types of restorations provided sufficient oral rehabilitation. However, only completely implant-supported prostheses avoided soft tissue ulcers. The cumulative success rate was approximately 75% after 7 years for group 1 patients and about 86% after 10 years for group 2 patients. The success rates for implants placed after the change in strategy were approximately 86% (group 1) and 94% (group 2) after 5 years. Based on these experiences, it is suggested that irradiated patients should be restored with exclusively implant-supported prostheses, without any mucosal contact.

Adult↗

PubMedDate not supplied

A new application for craniofacial implants: wigs.

PURPOSE: The purpose of this study was to describe a new application of craniofacial implants, as anchoring elements for wigs. MATERIALS AND METHODS: In two patients, a split-skin graft was used to close a soft tissue defect in the occipital, parietal, temporal, and frontal region (defect size of 10 cm x 33 cm and 10 cm x 14 cm). Six titanium implants were placed in each patient. Six months after implant placement, abutment connection was performed and titanium magnets were adapted. Subsequently, an implant-retained wig was constructed. RESULTS: In a follow-up period of between 10 and 22 months no implant failed. The incorporated wigs effectively retain a functionally and cosmetically successful craniofacial rehabilitation. CONCLUSION: Despite these successful treatments, further research is needed before craniofacial implants as anchoring elements for wigs can be considered a standard option in the rehabilitation of craniofacial alopecic defects.

Adolescent↗

PubMedDate not supplied

Implant-supported mandibular telescopic prostheses in oral cancer patients: an up to 9-year retrospective study.

PURPOSE: The aim of this retrospective study was to present the results of implant-supported telescopic prostheses in the mandible after removal of malignant tumors. MATERIALS AND METHODS: Between 1991 and 2000, 24 patients with squamous cell carcinoma (16 irradiated, eight nonirradiated) underwent mandibular rehabilitation with implant-supported telescopic prostheses. A total of 111 dental implants were placed. Treatment complications were observed. The cumulative survival rates of the implants and prostheses were evaluated by lifetable analysis. RESULTS: Within a mean follow-up period of 30 months (1 to 108 months), only three implants failed. All other implants are still in function. Of 24 patients, 23 were satisfied with their implant-supported telescopic restorations. Soft tissue, implant, or prosthetic complications occurred very rarely. The cumulative implant survival rate was about 97% and the cumulative prosthesis survival rate was about 95% at 9 years. CONCLUSION: Implants and implant-supported telescopic maxillofacial prostheses can successfully remain in function over a long period. Increased implant and prosthetic complications should not be expected. Therefore, telescopic implant attachments seem to be very useful as a treatment option for prosthetic restoration of the mandible in tumor patients.

Adult↗

PubMedDate not supplied

Concept of surgical and implant-supported prostheses in the rehabilitation of patients with oral cancer.

Thirteen irradiated and 14 nonirradiated patients were treated after resection of a malignant oral lesion. With a follow-up period of 26 months, 3 of 48 implants in nonirradiated patients and 4 of 57 implants in irradiated patients failed. In comparison to implant-tissue-supported prostheses, exclusively implant-supported prostheses demonstrated better results with regard to soft tissue trauma and function of the prosthesis.

Adult↗

PubMedDate not supplied

Titanium implants in the zygoma as retaining elements after hemimaxillectomy.

Obturator prostheses require anchoring elements in the partially resected maxilla to provide stability and oronasal separation. Anchoring elements are usually overstressed because of the lack of collateral support. Intraoral titanium implants can provide additional retention and avoid mechanical overstress of the anchoring elements in the residual maxilla. Treatment with intraoral implants into the zygoma for the support of an obturator prosthesis is reported.

Dental Implantation, Endosseous↗

PubMedDate not supplied

Implant-supported telescopic restorations in maxillofacial prosthetics.

Eight partially irradiated oral cancer patients were treated using either mandibular implant and mucosa-supported telescopic coping prostheses or a restoration that was completely implant-supported with telescopic copings. Both types of restorations provided sufficient positional stability and peri-implant hygiene, and functional and esthetic improvement. However, only the completely implant-supported telescopic prosthesis avoided soft tissue ulcers that had the potential for the development of osteoradionecrosis. This type of restoration can especially be recommended for irradiated patients.

Cranial Irradiation↗