PubMed Health⌕ Search

Biomedical subjects

Herbert Deppe

Publications and source records attributed to Herbert Deppe.

10 recordsLinked to original sources
PubMed2007

New advances in fluorochrome sequential labelling of teeth using seven different fluorochromes and spectral image analysis.

Fluorochrome sequential labelling of mineralizing tissues is commonly used in different fields of clinical and basic research. Recently we improved polychrome fluorescent sequential labelling of bone by applying spectral image analysis to discriminate seven different fluorochromes. Although basic mineralization processes of bone and teeth follow comparable principles, the respective tissues differ in terms of matrix composition and mineral assembly. The aim of this study therefore was to investigate the feasibility of this new technique for polychrome sequential labelling of teeth and to demonstrate the advantages in the field of dentistry. Furthermore, the exact labelled area of each fluorochrome could be measured, even in regions of overlapping fluorochromes. The technique presented may provide a basis for further investigations of mineralization processes of different anatomical dental structures.

Animals↗
PubMed2005

Laser-assisted three-dimensional surface modifications of titanium implants: preliminary data.

BACKGROUND: Modern implant systems used in the cervical region do not allow for the ingrowth of peri-implant mucosa. The aim of the present study was to use a laser to modify titanium implants used in that region in order to promote mucosa ingrowth, thereby creating a biological barrier against bacterial infection. METHODS: A KrF-excimer laser (lambda=248 nm) was used (tau=30 ns, fmax=50 Hz, Emax=1.2 J). Craters were generated, under normal atmospheric conditions or in vacuum, in the polished regions of 18 Frialit 2 implants. Surface analysis was performed using a scanning electron microscope, an energy dispersive X-ray technique, and profile analysis. RESULTS: By adjusting the parameters used, it was possible to create canals with widths of up to 100 microm and depths of 450 microm. Canal morphology was influenced by the laser energy and the surrounding atmospheric conditions. Irradiation with 3,000 pulses (650 mJ per pulse) resulted in rough surfaces under normal atmospheric conditions, whereas these parameters resulted in smooth surfaces in vacuum. The surface chemistry was also influenced by the laser parameters used. CONCLUSION: Laser-assisted modification of titanium surfaces permits fabrication of 3-D surface modifications. The surface chemistry can also be influenced, depending upon the parameters chosen. Further studies are necessary to evaluate whether ingrowth of mucosa into the canals can be realized.

Dental Implantation, Endosseous↗
PubMed2005

Polychrome labeling of bone with seven different fluorochromes: enhancing fluorochrome discrimination by spectral image analysis.

Bone formation and remodeling in vivo can be assessed by polychrome labeling using calcium-binding fluorescent dyes. The number of fluorochromes, however, limits this technique due to the fact that with increasing number, fluorescent spectra inevitably overlap, which makes discrimination more difficult. In order to enhance discrimination, we performed spectral image analysis. Non-critical size defects of the femur of male Wistar rats served as a model for bone formation. Eight different fluorochromes (calcein blue, xylenol orange, calcein, alizarine complexone, doxycycline, rolitetracycline, hematoporphyrin, and BAPTA) were administered sequentially subcutaneously every third day starting at day 4 after surgery. Following, bone specimen were embedded in methylmethacrylate and analyzed by spectral image acquisition using a Sagnac type interferometer (ASI, Israel). Seven of the eight applied fluorochromes could be resolved using spectral image examination. With BAPTA, we present a new fluorochrome suitable for bone labeling. Due to the superior sensitivity of the spectral image acquisition, the thickness of the bone sections could be reduced so that 5 mum thick sections could be analyzed. Spectral decomposition and subsequent linear unmixing allows depiction of each individual fluorochrome without interference of any other, enabling a reliable and superior morphometric analysis of labeled regions.

Animals↗
PubMed2004

Microstructured dental implants and palatal mucosal grafts in cleft patients: a retrospective analysis.

BACKGROUND: In cleft patients, implant dentistry has become an integral part of oral rehabilitation. However, a lack of keratinized mucosa is found in many cases which may have adverse effects on the long-term success of dental implants with microstructured surfaces. Therefore, the aim of this study was to evaluate whether mucogingival surgery is of value in the treatment of these patients. PATIENTS: Between 1991 and 2002, a total of 35 microstructured dental implants were inserted in 32 cleft patients. In 18 patients, vestibular scars extended to the rim of the marginal mucosa of the implants and the gingiva of the adjacent teeth. To enhance the soft tissue condition, mucogingival surgery was performed using palatal mucosal grafts. METHODS: In May 2002, 29 implants and 16 mucosal grafts were evaluated. Assessment included radiological and clinical parameters. RESULTS: Three implants were lost. Most mucosal grafts showed shrinkage of up to 30%. Clinical and radiological parameters, however, showed results that were very similar to those from non-cleft patients. CONCLUSION: These results support the hypothesis that keratinized mucosal grafts show long-term success in the cleft region as well. Moreover, it may be concluded that a combination of dental implants with a rough surface and palatal mucosal grafts can be recommended for oral rehabilitation of cleft patients.

Adolescent↗
PubMedDate not supplied

Titanium deposition after peri-implant care with the carbon dioxide laser.

PURPOSE: Titanium endosseous implants are becoming increasingly important in dentistry because of their excellent long-term results. However, it has been reported that these implants may lead to higher concentrations of titanium, especially in the lungs and kidneys. The purpose of this study, therefore, was to determine whether CO2 laser-assisted decontamination of exposed implant surfaces is associated with an increase in titanium release. MATERIALS AND METHODS: In 6 beagle dogs, a total of 60 implants were placed. After osseointegration and second-stage surgery, peri-implantitis was induced by cotton floss ligatures for 12 weeks. Surgical treatment consisted of granulation tissue removal, including decontamination of the implant surface with 3 different methods. Twenty implants were decontaminated conventionally by an air-powder abrasive for 60 seconds. Another 20 implants were decontaminated by laser treatment alone. The last 20 implants were treated conventionally by air-powder abrasive and then lased. Four months later, fresh tissue samples of various tissues were evaluated by histologic and chemical analysis. RESULTS: Quantitative analysis indicated that titanium accumulation could be detected, especially in the spleen, liver, oral mucosa, regional lymph nodes, lung, and kidney in the beagle dog model. DISCUSSION: The concentrations found did not exceed those previously reported in the literature. CONCLUSION: These results support the hypothesis that CO2 laser-assisted therapy of ailing implants will not result in excessive titanium concentrations in tissues. Accordingly, CO2 lasers appear suitable and safe for peri-implant gingival surgery.

Air↗
PubMedDate not supplied

Effects of osteopromotive and anti-infective membranes on bone regeneration: an experimental study in rat mandibular defects.

PURPOSE: Reconstructive surgical treatment with osteopromotive membranes has become an integral part of implant dentistry. Nevertheless, there are still instances in which this technique alone is of limited or no benefit. The aim of the present study was to determine whether a combination of titanium membranes coated with transforming growth factor beta1 (TGF-beta1) and insulin-like growth factor I (IGF-I) is of value in the regeneration of so-called critical-size defects in the rat model. An analysis was made of whether or not locally administered antibiotics are deleterious to bone regeneration. MATERIALS AND METHODS: A total of 24 rats were included in the study and were divided into 4 groups, each with 6 animals. Critical-size defects were created bilaterally and covered by titanium membranes coated with (1) polylactide, (2) polylactide and clindamycin, (3) polylactide and growth factors, or (4) polylactide, clindamycin, and growth factors. All 24 contralateral defects were covered by titanium membranes without any substrate (controls). Four weeks after treatment the animals were sacrificed. RESULTS: In groups 3 and 4, most defects showed thin but almost complete bridging of the defects with new bone formation. In particular, clindamycin had no inhibitory effect on the regeneration of bone. Nevertheless, after 28 days, there was no significant difference between the individual groups (including controls) with respect to the total amount of newly formed bone. DISCUSSION AND CONCLUSION: These results support the hypothesis that coating titanium membranes with TGF-beta1/IGF-I leads to almost complete bony bridging of critical-size defects without voluminous carrier materials. Moreover, simultaneous administration of clindamycin seems possible.

Animals↗
PubMedDate not supplied

Comparative value of attachment measurements in implant dentistry.

PURPOSE: In implant dentistry, the level of bone attachment is normally assessed by clinical and radiologic parameters. In the literature, however, the accuracy of these measurements has been a source of controversy. The purpose of this study was to assess the reliability of attachment measurements in the beagle dog model. MATERIALS AND METHODS: In 6 beagle dogs, a total of 60 implants were placed. Bony defects resulting from plaque accumulation were treated surgically. All defects were evaluated at the time of surgery (T3) and 4 months later (T4). Evaluation included standardized measurements on radiographs, pressure-forced implant probing, and histometry. Furthermore, both conventional and digital radiographic techniques were used. RESULTS: Both radiographic techniques showed very similar results at T3 and T4. At time T4, pressure-forced probing revealed statistically significantly different values than those obtained with radiography and histometry. When radiographic and histometric measurements were compared, no significant differences were found at either time T3 or time T4. DISCUSSION: In this study, histometry showed better accordance with radiography than with pressure-forced probing. These results support the hypothesis that peri-implant attachment should be evaluated with a combination of both clinical and radiologic parameters. CONCLUSION: The exclusive use of radiography cannot be recommended for the measurement of peri-implant attachment.

Alveolar Bone Loss↗
PubMedDate not supplied

Bone regeneration after peri-implant care with the CO2 laser: a fluorescence microscopy study.

PURPOSE: The carbon dioxide (CO2) laser has been shown to be suitable for the treatment of ailing implants. However, comparatively little is known about bone regeneration after laser treatment. Therefore, the purpose of this study was to determine the course of bone regeneration after peri-implant care with the CO2 laser. MATERIALS AND METHODS: In 6 beagle dogs, a total of 60 implants and bony defects were treated either conventionally by air-powder abrasive (group 1), by laser irradiation alone (group 2), or by a combination of the 2 (group 3). After therapy, polychrome sequence labeling was performed using 4 different markers. Four months later, after sacrifice, histologic sections were photographed and scanned. In each specimen, the 4 stained areas were detected with special software and indicated as a percentage of the standardized measurement frame. Lastly, the time-course of the bone regeneration was determined for each of the 3 therapy groups. RESULTS: Fluorescence microscopy demonstrated maximum bone regeneration after 8 weeks in all 3 therapy groups. In this period, groups 2 and 3 showed significantly greater amounts of newly formed bone than group 1 (P < .03 and P < .05, respectively). However, there was no difference in bone regeneration between groups 2 and 3. DISCUSSION: Using fluoresence microscopy, it was possible to analyze and interpret the bone regeneration processes during all 4 application phases of the 3 groups. CONCLUSIONS: These results support the hypothesis that CO2 laser irradiation renders significantly more new bone formation, especially 5 to 8 weeks postoperatively, than conventional decontamination in the dog model. Further investigation will be required to determine the clinical efficacy.

Air Abrasion, Dental↗