Biomedical subjects

Joerg Wiltfang

Publications and source records attributed to Joerg Wiltfang.

At least 19 recordsLinked to original sources

PubMed2006

Influence of platelet-rich plasma on a bioglass and autogenous bone in sinus augmentation. An explorative study.

Platelet-rich plasma (PRP) has been introduced to the field of oral and maxillofacial surgery for a decade, but its beneficial effects on maxillary sinus augmentation remain unclear. The aim of this study was to evaluate the short- and long-term effects of PRP on osseointegration following single-stage sinus augmentation in a randomized prospective animal study. The maxillary premolars of 24 minipigs were extracted bilaterally and allowed to heal for 2 months. Consecutively all animals underwent bilateral sinus floor elevation using autogenous bone, Biogran as well as a combination of the materials with PRP. Three dental implants (Ankylos, Dentsply Co., Mannheim, Germany) were installed in each sinus simultaneously. Four animals were sacrificed at each period of observation (1, 2, 8 and 12 months). Microradiographic images of the specimens were made for quantitative evaluation of the bone-implant contact (BIC) and light microscopic images were made for qualitative analysis. An increment of the BIC during the observation time could be seen over the observation time in all groups. Autogenous bone exhibited a level of BIC from 25.1 +/- 9.96% at 1 month to 55.1 +/- 13.10% at 12 months; on adding PRP, the BIC ranged from 28.4 +/- 4.64% to 52.5 +/- 17.06%. Biogran with and without PRP led to BIC levels from 16.3 +/- 4.64% to 37.6 +/- 16.40% and 21.7 +/- 4.33% to 46.6 +/- 19.37%, respectively. The results of this study did not show a significantly positive effect of PRP on the BIC following sinus augmentation in both groups.

Alveolar Ridge Augmentation↗

PubMed2006

Expression of bone matrix proteins during the osseus healing of topical conditioned implants: an experimental study.

OBJECTIVES: Osseointegration of implants depends on time and local bone conditions regarding quality and quantity. This led to the bone classification by Lekholm et al. The aim of the present study was to follow the expression of bone matrix proteins during the phase of osseointegration after conditioning of the bone bed by means of immunohistochemistry. METHODS: In the porcine frontal skull, implant beds of identical size were created. Before placement of the implants (Ankylos 4 x 3.5 mm), the implant beds were conditioned using bone condensation (cond), an osteoinductive collagen (Co) and platelet-rich plasma (PRP). These conditioning methods were compared with standard procedure. The animals were sacrificed after 2, 4 and 8 weeks. The specimens were then analyzed by light microcopy and immunohistochemistry for expression of bone morphogenic proteins (BMP)2, procollagen I and osteocalcin (OC). RESULTS: Light microscopy revealed an initial effect of condensation and the bovine collagen at 2 weeks in comparison with the standard group. The PRP did not achieve a significant effect. At 8 weeks, the results of the standard, bone condensation and the bovine collagen group had aligned. The PRP group showed a significantly lower bone-implant contact (BIC) (P=0.003) compared with the standard group. BMP2 expression was significantly higher in all evaluated test groups at 4 and 8 weeks, as well as at 2 weeks in the condensation group. The procollagen I expression at 2 weeks was significantly increased for PRP and lower in the collagen and condensation group compared with standard procedure. Values for 4 and 8 weeks were slightly higher than in the standard group. No significant differences were obvious in the OC group at any time. CONCLUSIONS: During the initial healing phase, an effect of the evaluated methods of topical bone conditioning can be demonstrated by differences in the expression of BMP2 and procollagen I. These findings had leveled at 8 weeks and were, in contrast, not detectable in the expression of OC or by means of light microscopy.

Animals↗

PubMed2006

Lack of beneficial effects of platelet-rich plasma on sinus augmentation using a fluorohydroxyapatite or autogenous bone: an explorative study.

BACKGROUND: Maxillary sinus augmentation is frequently necessary before placement of dental implants in the posterior maxilla. Besides autogenous bone graft, various bone substitutes have been used, with favourable results. Although platelet-rich plasma (PRP) has been used in the field of oral and maxillofacial surgery for years, its beneficial effects on osseous regeneration still remain unclear. The aim of this study was to evaluate the short and long time effects of PRP on single-stage sinus augmentation using autogenous bone or a fluorohydroxyapatite (Algipore) in a randomized prospective animal study. METHODS: After extraction of maxillary premolars of sixteen minipigs, the wounds were allowed to heal for 2 months. Then, sinus augmentations were performed bilaterally using one of the following grafting materials: autogenous bone and Algipore with or without PRP. Three dental implants (Ankylos) were installed in each sinus simultaneously. Four animals were euthanized at each period of observation (1, 2, 8 and 12 months). Implant-bearing specimens were sectioned bucco-lingually along the long axis of implants and undecalcified ground specimens were prepared. The bone-implant-contact (BIC) was measured by means of microradiographic examination. For histological evaluation, the specimens were stained with toluidin blue, and the percentage of the newly formed bone and the remaining bone substitute were evaluated. RESULTS: The grafting materials chosen showed increasing levels of BIC and newly formed bone throughout the period of observation in both PRP and non-PRP groups. Adding PRP resulted in lower BIC and newly formed bone compared with autogenous bone grafts or Algipore alone. However, a statistical significance was not found. The percentages of the remaining bone substitute in both the PRP and non-PRP groups were closely comparable in all observation periods. CONCLUSIONS: The application of PRP could not reveal significant beneficial effects on the BIC, the percentage of the newly formed bone and the remaining bone substitute in this study.

Animals↗

PubMed2005

Enhanced bone regeneration with a synthetic cell-binding peptide--in vivo results.

This in vivo study compared the regenerative processes within defined defects of the porcine skull after delivery of a porous algae-derived hydroxyapatite (adHA), a similar, experimental adHA carrying the cell binding peptide P-15, used solely and in combination with 25% autogenous bone (AB). Particulated AB served as a control group. During an observation period of 26 weeks, microradiography and histology were performed at four specific times. Significantly higher mineralization rates (p=0.008) were found 4 weeks after application of the bioactive material in combination with AB. At 12 weeks there was a significantly higher mineralization (p=0.036) following the application of the bioactive form alone. This study showed significantly higher mineralization after use of a P-15 bioactivated material at early stages. Thus, it can be concluded that the application of the P-15 sequence to an hydroxyapatite accelerates the process of early bone formation, whereas no long-term effect was traced.

Animals↗

PubMed2005

Untreated 'blow-in' fracture of the orbital floor causing a mucocele: report of an unusual late complication.

BACKGROUND: Several severe complications have been described with blow-in fractures. Therefore, immediate surgical treatment of these fractures has been recommended. To date, there is only minimal knowledge on long-term complications of blow-in fractures that have remained untreated. The present case report describes a late complication of an untreated blow-in fracture of the orbital floor. CASE: A 37-year-old male was involved in a car accident 16 years before. At that time, a non-dislocated midfacial fracture was diagnosed and remained untreated because of the lack of clinical symptoms. Four months before surgery an exophthalmos of the left globe began to develop. CT examination revealed a consolidated blow-in fracture of the left orbital floor and an opaque mass around the dislocated bony fragments. By an infraorbital approach the bony fragments and the surrounding mass were removed. Histological examination of the removed material revealed a cystic structure lined with respiratory epithelium. Therefore, the diagnosis 'post-traumatic mucocele in the orbit caused by dislocated respiratory epithelium from the maxillary sinus' was made. CONCLUSION: Even if blow-in fractures do not cause complications immediately after trauma, late complications like mucoceles can occur after several symptom-free years. Therefore, early reconstruction should be intended even in asymptomatic cases of blow-in fractures with minimal displacement of the bony fragments.

Accidents, Traffic↗

PubMed2005

Bone regeneration in osseous defects using a resorbable nanoparticular hydroxyapatite.

PURPOSE: This animal study examined the de novo bone formation in bony defects following the insertion of autogenous bone alone versus an injectable nanoparticle hydroxyapatite alone and in combination with 25% autogenous bone. The regenerative potentials of the tested materials were compared with each other. MATERIALS AND METHODS: A model with biological similarity to humans with regard to bone regeneration was a prerequisite for the transferability of the results to clinical practice. Therefore, the adult domestic pig was the animal of choice. A total observation period of 6 months was selected. Microradiographic and histologic evaluation of the bone specimens was completed at 8 defined times. RESULTS: Microradiography indicated mineralization rates in the 2 bone substitute groups that were not significantly lower than those found in the autogenous bone group. Histologically, there was suitable osseointegration and osteoconduction of the used material. Complete resorption of the nanoparticle hydroxyapatite had taken place after 12 weeks. CONCLUSIONS: It can be concluded that the evaluated nanoparticular hydroxyapatite met the clinical requirements for a bone substitute material within the limits of this experimental setting. Due to its microstructure, complete resorption took place during the course of this study.

Absorbable Implants↗

PubMed2005

Investigation of the expression of melanoma antigen-encoding genes (MAGE-A1 to -A6) in oral squamous cell carcinomas to determine potential targets for gene-based cancer immunotherapy.

MAGE genes are silent in normal tissues except testis but are expressed in a variety of neoplastic lesions, and therefore represent ideal targets for immunotherapy. We analysed the expression of 6 MAGE-A genes (MAGE-A1 to -A6) to determine potential implications of these antigens as targets for immunotherapy in oral squamous cell carcinoma (OSCC). Oral tumor specimens (n=21) and non-neoplastic tissue samples (n=10) of oral mucosa from healthy patients were examined by a highly sensitive reverse transcription-nested polymerase chain reaction (MAGE-1- to -6 assay) which detect any cancer cells that express at least one of six MAGE subtype genes and allows also the identification of individual MAGE isotypes (M1 to M6). MAGE expression was restricted to neoplastic specimens. No expression of MAGE was observed in the non-neoplastic normal oral mucosal tissues. Fifteen of 21 (71%) oral carcinomas expressed at least one of MAGE-A1 to -6. The expression pattern of subtypes was heterogeneous: 62% of the tumor patients were positive for MAGE-3, 57% for MAGE-4, 48% for MAGE-6, 43% for MAGE-1, 38% for MAGE-2 and 24% for MAGE-5. Also coexpression of the genes could be determined: 13 (62%) coexpressed two, 10 (48%) coexpressed three, 8 (38%) coexpressed four, 6 (29%) coexpressed five and 5 coexpressed six of the 6 subtypes tested. The high incidence of MAGE expression in oral cancer indicates that monitoring of MAGE-A subtype expression in OSCC may be of potential interest to determine new immunotherapeutic targets and may be a possibility of specific immunotherapy with polyvalent anti-genes for this disease.

Antigens, Neoplasm↗

PubMed2004

Sensor-based laser ablation for tissue specific cutting: an experimental study.

The interaction of laser light and tissue causes measurable phenomenons. These phenomenons can be quantified and used to control the laser drilling within a feedback system. Ten halves of dissected minipig jaws were treated with an Er:YAG laser system controlled via a feedback system. Sensor outputs were recorded and analyzed while osteotomy was done. The relative depth of laser ablation was calculated by 3D computed tomography and evaluated histologically. The detected signals caused by the laser-tissue interaction changed their character in a dramatic way after passing the cortical bone layer. The radiological evaluation of 98 laser-ablated holes in the ten halves showed no deeper ablation beyond the cortical layer (mean values: 97.8%). Histologically, no physical damage to the alveolar nerve bundle was proved. The feedback system to control the laser drilling was working exactly for cortical ablation of the bone based on the evaluation of detected and quantified phenomenon related to the laser-tissue interaction.

Animals↗

PubMed2004

Reconstruction of skull bone defects using the hydroxyapatite cement with calvarial split transplants.

PURPOSE: We sought to present a new method for primary reconstruction of traumatic or tumor calvarial defects. PATIENTS AND METHODS: Forty-one patients underwent reconstruction of calvarial bone defects between October 1998 and December 2001. Among them were 19 patients who needed reconstruction of the calvaria due to traumatic bone loss. Five of these trauma cases had insufficient primary reconstruction of the calvaria. Tumor resection caused calvarial defects in 22 patients. For primary reconstruction of the skull bone defects, calvarial split grafts were used to cover the defect as accurately as possible. The monocortical layers of the calvaria were fixed with titanium miniplates. Irregular defects surrounding the transplanted regions were filled with hydroxyapatite cement. In one case of posttraumatic bone loss, hydroxyapatite cement alone was sufficient to reconstruct the defect. RESULTS: The follow-up of each patient was at least 6 months; the longest period was 38 months. Evaluated clinical and radiologic results are stable, showing no measurable side effects. CONCLUSION: Hydroxyapatite cement alone or in combination with calvarial split grafts gave clinically and aesthetically stable results in the reconstruction of skull bone defects. The cement can be used for many reconstruction possibilities in craniofacial surgery.

Adult↗

PubMed2004

Effects of platelet-rich plasma on bone healing in combination with autogenous bone and bone substitutes in critical-size defects. An animal experiment.

OBJECTIVES: An animal study was carried out to investigate the influence of platelet-rich plasma (PRP) on the regeneration of bony defects. MATERIAL AND METHODS: Critical-size defects in the forehead region of a mini-pig were filled with randomly distributed combinations of autogenous bone, tricalcium-phosphate granules (CeraSorb), bovine spongious blocks (BioOss) and a bovine bone inducing collagenous sponge (Colloss) with and without PRP in two preparations (Cusasan, 3i). The animals were killed after 2, 4 and 12 weeks. The specimens were evaluated microradiographically and immunohistologically. RESULTS: Autologous bone (38 +/- 9.9%) and Colloss (52.6 +/- 4.0%) showed the highest remineralization rates at 2 weeks. The initial high expression of BMP-2 in the Colloss-group gives evidence of an early initiation of bony regeneration. At 2 weeks PRP ad modum 3i was able to enhance bone healing significantly (P=0.028) only when applied in combination with autogenous bone (62.8 +/- 1.6%). Four weeks after surgery, both PRP preparations did no longer increase bony regeneration in the autogenous groups. The osteoconductive effect of Bio-Oss (38.7 +/- 5.5%) and CeraSorb (41+/-4.9%) was remarkable as well 4 weeks after surgery. Nevertheless, the addition of PRP hardly influenced bony regeneration, ceramic degradation or cytokine expression when bone substitutes were applied. At 12 weeks, the level of reossification had adjusted similarly in all groups. CONCLUSION: PRP did not add additional benefit when xenogenic bone substitutes were used. However, a significant effect on bone regeneration was found in the autogenous group initially when PRP is added.

Animals↗

PubMed2003

Er:YAG laser osteotomy directed by sensor controlled systems.

BACKGROUND: Great efforts have been taken in the past to develop laser systems suitable for bone cutting. Laser systems emitting light in the infrared spectrum (2.9, 3.0 microm) have been found to be ideal for efficient bone ablation with very little carbonization. AIM: To evaluate a new laser bone cutting system enabling the automatic detection of different tissue qualities by an integrated sensor to avoid damage to sensitive structures such as blood vessels or nerves. MATERIAL: An Erbium:YAG laser containing an integrated closed-loop control system, was constructed and tested on dissected bone. Process emissions such as resonance changes caused by the interaction of laser light and various tissue structures can be used for a controlled system. Sensor signals from a photodiode and a piezo-electric accelerometer were received and processed to guide the laser osteotomy. METHODS: Tests were performed on dissected bone specimens from rabbit femur (14) and minipig jaw (6). After laser application, the bone specimens were evaluated macroscopically and histologically. RESULTS: The specimens were evaluated histomorphometrically for the depth of cortical bone ablation when the closed-loop control system switched off the laser. Mean courses of 97.45% (pig) and 97.83% (rabbit) showed that the systems work with precision. CONCLUSION: After penetrating the cortical bone layer, the laser beam was promptly interrupted due to extreme changes of the signal character received by the sensor system. The in vitro tests of this new laser closed-loop control system were successful.

Aluminum Silicates↗

PubMed2003

Sinus floor augmentation with beta-tricalciumphosphate (beta-TCP): does platelet-rich plasma promote its osseous integration and degradation?

When dental implants are to be inserted, sinus floor augmentation is an effective treatment procedure to improve bone height in the posterior maxilla. In addition to autogenous bone material, allogenic materials, e.g. beta-tricalciumphosphate (beta-TCP), have been used successfully. The purpose of this study was to investigate whether the combination of beta-TCP with platelet-rich plasma (PRP) enhances bony regeneration and resorption of the tricalciumphosphate material. In a randomized prospective trial, 45 sinus floor elevations were performed in 39 patients. In 22 sites, PRP was added to the beta-TCP granules, while in 23 sites beta-TCP without PRP was used. Six months later, bone specimens were harvested from the augmented region during the implant insertion procedure. The formation of new bone was about 8-10% higher when PRP was applied. A faster degradation of the ceramic bone substitute was not observed. In conclusion, when PRP was added to beta-TCP, bone regeneration was supported to a small extent. However, the resorption of beta-TCP was not accelerated and foreign-body giant cells and soft tissue surrounding the beta-TCP granules were present.

Absorbable Implants↗

PubMed2003

Micro-lightguide spectrophotometry as an intraoral monitoring method in free vascular soft tissue flaps.

PURPOSE: The aim of this prospective study was to measure the hemoglobin oxygen saturation (HbO(2)%) and relative Hb concentration of free vascular soft tissue flaps using micro-lightguide spectrophotometry. The objective was to measure the normal range and topographic differences in HbO(2)% and rel. Hb conc. in tissue transfers before establishing this as a clinical method for monitoring perfusion and vitality. PATIENTS AND METHODS: In 39 patients who had received free vascular soft tissue flaps (34 radial forearm flaps; 8 latissimus flaps) to cover defects after tumor surgery, the capillary HbO(2)% in transferred tissue was measured spectrophotometrically preoperatively at the donor site and postoperatively up to the third postoperative day. On average about 500 hemoglobin spectra (200 to 800 spectra) were measured over each 24-hour period. Additionally, the relative Hb concentration was determined for the individual measuring times. The measurements were carried out topographically on the flap base, flap center, and flap periphery. RESULTS: The preoperative HbO(2) values at the donor site of free soft tissue flaps were between 20% and 40% in all topographic regions. In the case of clinically successful flaps, a normal distribution of the HbO(2) values of 20% to 80% was obtained in the immediate postoperative period, and from the second day on, a normal distribution of 45% to 60%. In the case of 2 flaps with partial necrosis, HbO(2) values of less than 10% to 15% were measured from the second postoperative day on. The relative Hb concentration had no influence on the amount of HbO(2)% measured in the transferred capillaries. In the postoperative phase, here was no topographic difference between the individual flap regions. CONCLUSIONS: As a noninvasive method, micro-lightguide spectrophotometry permits quantitative determination of HbO(2)% and relative Hb concentration over the entire surface of soft tissue flaps. In the case of partially unsuccessful flaps, HbO(2) values of less than 10% to 15% were measured beforehand, thus indicating that these HbO(2) values are not sufficient to support the vitality of the free tissue transfer. When combined with clinical observation, application can be recommended for the vitality measurement of free soft tissue flaps and permits more information to be obtained on topographic capillary perfusion conditions.

Adolescent↗

PubMed2003

Intraoperative Image-Guided Surgery of the Lateral and Anterior Skull Base in Patients with Tumors or Trauma.

The aim of this investigation was to evaluate the suitability and usefulness of the Stealth Stationtrade mark intraoperative guiding system (Medtronic Sofamor Danek, Memphis, TN) in a variety of indications. Eleven intraoperative image-guided procedures were performed for anterior or lateral skull base lesions. The most common neurosurgical approaches included frontal, coronal, and parietotemporal access. Neuronavigation reliably allowed the extent of tumor configuration and risk zones (e.g., blood vessels) to be visualized. Thus, gross tumor resection was achieved in 6 of 7 patients and facilitated reconstruction by the maxillofacial surgeon, resulting in radiologically symmetrical and clinically satisfying results. Postoperatively, one patient was blind from a continuity defect of the optic nerve caused by a bone fragment. Despite destruction of anatomical landmarks related to tumor invasion or intraoperative bone removal, neuronavigation proved helpful in the reconstruction of bony structures. Overall, the use of neuronavigation in interdisciplinary surgery for complicated tumors or trauma of the anterior or lateral skull base allows more radical resection associated with less morbidity.

Journal Article↗

PubMed2003

Cherubism: clinical evidence and therapy.

Cherubism is a hereditary childhood disease of autosomal dominant inheritance that is more common in the male sex. Some cases have also revealed a mutation of the gene FGF-RIII (fibroblast growth factor receptor III). The clinical picture of cherubism is characterized by painless symmetrical swelling of the mandible and polycystic destruction of the mandibular bone structure. Complications include delayed dentition, dental root resorption, malalignment of teeth, and impacted teeth. The disease progression comes to a halt of its own accord at the end of puberty. Spontaneous recoveries have been observed. Histologically, multinuclear giant cells with osteoclastic activity, which correspond to a giant cell granuloma, are found in fibrous stroma. It is generally agreed that decisions about surgical intervention should be considered carefully. A case report describes the course of the disease and therapy of a female patient with a periorbital manifestation of cherubism. The latero-orbital enlargement of the intraorbital and latero-orbital region of the zygomatic bone resulted in displacement of the orbital contents with a motility disorder of the eyes. The motility disorder was eliminated by reduction of the diseased hard tissue as well as by carrying out a modeling orbitotomy and by reconstructing an anatomically correct localized and irregular bilateral osseous structure of the zygomatic bone in the intraorbital and latero-orbital region.

Adult↗

PubMed2003

Influence of early hard palate closure in unilateral and bilateral cleft lip and palate on maxillary transverse growth during the first four years of age.

OBJECTIVE: To evaluate and compare the effects of early primary closure of the hard palate on the anterior and posterior width of the maxillary arch in children with bilateral (BCLP) and unilateral (UCLP) cleft lip and palate during the first 4 years of life. DESIGN: A retrospective, mixed-longitudinal study. SETTING: Cleft Palate Center of the University of Erlangen-Nuremberg. SUBJECTS AND METHODS: The present investigation analyzes longitudinally 42 children with UCLP and 8 children with BCLP between 1996 and 2000 with early simultaneous primary closure of lip and hard palate (4 to 5 months). Palatal arch width was measured on dental casts with a computer-controlled three-dimensional digitizing system, and their growth velocities were calculated from consecutive periods (mean follow-up 39 months). Differences in growth velocities were compared with those of 25 children with UCLP and 15 children with BCLP with delayed closure of hard palate (12 to 14 months). RESULTS AND CONCLUSIONS: There was no significant difference in terms of anterior and posterior maxillary width between early and delayed closure of hard palate within the first 4 years of life.

Age Factors↗

PubMed2002

Endoscopically assisted Le Fort I osteotomy to correct transverse and sagittal discrepancies of the maxilla.

PURPOSE: The purpose of this report was to show the feasibility of the combination of a minimally invasive endoscopic approach to the maxilla with transverse and sagittal distraction procedures. MATERIALS AND METHODS: Four human cadavers were used for training of a minimally invasive access to the maxilla to perform a endoscopically assisted Le Fort I osteotomy, before this technique was applied in 3 patients with transverse and sagittal growth deficits of the maxilla. Access to the maxilla was gained through a small mucosa incision in the vestibule to create a visualization port to the maxillary sinus through a bur hole. Landmarks were identified through the endoscope before a Le Fort I osteotomy was performed using chisels of different shapes and angulations. In 2 patients the maxilla was split sagittally to perform a transverse maxillary expansion; in 1 patient, a buried distractor was applied close to the piriform aperture to correct a sagittal growth deficit in a hypoplastic maxilla. RESULTS: Endoscopic exposure of the maxillary sinus walls from within the sinus, the accurate identification of landmarks, and the creation of a Le Fort I osteotomy were achieved in all cases. Distractor application close to the piriform aperture rendered good stability. CONCLUSION: The results of these cases indicate that the endoscopic approach to the maxillary sinus allows excellent exposure of the sinus walls to perform a endscopically assisted Le Fort I osteotomy. The combination of endoscopy and osteodistraction processes supports the tendency to perform minimally invasive, less-traumatizing surgical procedures, especially in individuals who are still growing.

Adolescent↗

PubMedDate not supplied

Examination of the bone-metal interface of titanium implants coated by the microwave plasma chemical vapor deposition method.

PURPOSE: Diamond layers can be plated with microwave plasma chemical vapor deposition (MWP-CVD) treatment on metal bases such as titanium-aluminum-vanadium alloy (Ti-6Al-4V). The bonding strength of the diamond layer to the metal base is very high, so that no fissures and partial loss of coating take place-well known phenomena that may occur with other coatings in tribologic material testing. In an experimental study using 40 New Zealand White rabbits, a new method for coating implant material was tested for stability of the bone-metal interface. MATERIALS AND METHODS: The results of histomorphometric and biomechanical evaluation of coated and uncoated probes implanted in the distal femur of 40 rabbits were compared. The animals were divided into 3 groups, with observation times of 42, 84, and 168 days. RESULTS: The bone-implant contact was 5% to 18% less in coated than in uncoated probes. Only the early group, with 42 days healing time showed significant differences. Values for the pull-off force of uncoated material were about 3 to 4 times higher than coated material (diamond layer = 2.7 microm). The force increased 2 to 3 times when 200-nm coatings were tested. Electron microscopy detected undercuts of the rough surface that were obturated by diamond when the coating was too thick. DISCUSSION: Diamond-coated material seems to have no corrosion problems in contrast to all other known implant material. CONCLUSION: An inert diamond layer on a metal base can become osseointegrated. Biomechanical stability increased by thinning the diamond coating.

Alloys↗