Publications by authors named "Cornelius von WIlmowsky"

38 Publications

Clinical outcome of patients with orbital fractures treated with patient specific CAD/CAM ceramic implants - A retrospective study.

J Craniomaxillofac Surg 2021 Jun 27;49(6):468-479. Epub 2021 Feb 27.

Department of Oral and Maxillofacial Surgery, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Glueckstrasse 11, 91054, Erlangen, Germany; Practice for Oral, Maxillofacial and Plastic Surgery, Fürther Straße 4a, 90429, Nürnberg, Germany.

The aim of this study was to determine whether patients benefit from a secondary reconstruction since it carries the risks of no improvement or worsening of their current situation. Patients treated with individual computer-aided-design/computer-aided-manufacturing (CAD/CAM) ceramic implants were reviewed. To ascertain changes throughout the secondary reconstruction, the study investigators reviewed ophthalmological examinations, took volumetric measurements of the orbits and asked the patients for evaluation of their situation before and after the reconstruction. Points addressed were double vision, visual acuity, field of vision, limitations in daily life and aesthetic considerations. A total of 14 patients were reviewed and 11 answered the questionnaire. Ophthalmological examinations showed that the physical integrity of the eye was maintained. Volumetric measurements preopeatively (33.94 ± 3.24 cm) and postoperatively (30.67 ± 2.07 cm) showed that a statistically significant overcorrection of orbital volume leads to good functional and aesthetic outcomes. Patients' subjective opinions were that they greatly benefitted, especially concerning limitations in daily life, which improved by 4.4 ± 2.8 points out of 10 possible points, and aesthetics, with an improvement of 5.9 ± 1.78 points. Based on these findings, we conclude that secondary reconstructions contribute to improvement of the patients' quality of life and therefore should be considered as an option to improve patients' condition.
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http://dx.doi.org/10.1016/j.jcms.2021.02.021DOI Listing
June 2021

The influence of nanoporous anodic aluminum oxide on the initial adhesion of Streptococcus mitis and mutans.

J Biomed Mater Res B Appl Biomater 2020 05 25;108(4):1687-1696. Epub 2019 Nov 25.

Department of Oral and Maxillofacial Surgery, University Hospital Erlangen, Glueckstraße, Erlangen, Germany.

The use of nanoscale surface modifications offers a possibility to regulate the bacterial adherence behavior. The aim of this study was to evaluate the influence of nanoporous anodic aluminum oxide of different pore diameters on the bacterial species Streptococcus mitis and Streptococcus mutans. Nanoporous anodic aluminum oxide (AAO) surfaces with an average pore diameter of 15 and 40 nm, polished pure titanium and compact aluminum oxide (alumina) samples as reference material were investigated. S. mitis and mutans were evaluated for initial adhesion and viability after an incubation period of 30 and 120 min. After 30 min a significantly reduced growth of S. mitis and mutans on 15 nm samples compared to specimens with 40 nm pore diameter, alumina and titanium surfaces could be observed (p < .001). Even after 120 min incubation there was a significant difference between the surfaces with 15 nm pore diameter and the remaining samples (p < .001). AAO surfaces with a small pore diameter have an inhibitory effect on the initial adhesion of S. mitis and mutans. The use of such pore dimensions in the area of the implant shoulder represents a possibility to reduce the adhesion behavior of these bacterial species.
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http://dx.doi.org/10.1002/jbm.b.34514DOI Listing
May 2020

A new standardized critical size bone defect model in the pig forehead for comparative testing of bone regeneration materials.

Clin Oral Investig 2020 May 15;24(5):1651-1661. Epub 2019 Aug 15.

Department of Oral and Maxillofacial Surgery, University of Erlangen-Nürnberg, Glueckstraße 11, 91054, Erlangen, Germany.

Objectives: The preclinical study aimed to establish a standardized preclinical model to investigate osseous graft consolidation in defect configurations of limited regenerative capacity.

Material And Methods: Critical size defects (CSD) were prepared and titanium tubes inserted for defect separation from local bone in the forehead area of 18 pigs. Defects were filled with demineralized bovine bone mineral (DBBM) or served as empty controls and were covered with a resorbable collagen membrane (CM) or left untreated. Six randomly selected pigs were sacrificed after 4, 8 and 12 weeks. Specimens were histologically and histomorphometrically analysed focusing on newly formed bone (NFB), demineralized bovine bone mineral (DBBM) and soft tissue (ST) proportions.

Results: Four weeks after defect preparation, no statistically significant difference concerning NFB quantity could be detected within the groups. Defects covered with the CM showed lower amounts of DBBM. After 6 and 12 weeks, defects augmented with DBBM in combination with a CM (8 weeks: 43.12 ± 4.31; 12 weeks: 43.05 ± 3.01) showed a statistically significant higher NFB rate compared to empty control defects covered with 8 weeks: 7.66 ± 0.59; 12 weeks or without a CM; 8 weeks: 8.62 ± 2.66; 12 weeks: 18.40 ± 2.40. CM application showed no significant impact on osseous defect regeneration or soft tissue formation. Superior NFB could be detected for basal aspect for several evaluation time points.

Conclusions: The modification of CSD with titanium tubes represents a suitable model to imitate a one-wall defect regeneration situation.

Clinical Relevance: The established model represents a promising method to evaluate graft consolidation in one-wall defect configuration.
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http://dx.doi.org/10.1007/s00784-019-03020-wDOI Listing
May 2020

Antiseptic negative pressure instillation therapy for the treatment of septic wound healing deficits in oral and maxillofacial surgery.

J Craniomaxillofac Surg 2019 Mar 19;47(3):389-393. Epub 2018 Dec 19.

Department of Oral and Maxillofacial Surgery (Head of the institution: Prof. Dr. med. Dr. med. Dent. Marco Rainer Kesting), University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Glückstraße 11, 91054, Erlangen, Germany; Section of Oral and Maxillofacial Surgery, Department of Otorhinolaryngology, Klinikum Augsburg Süd, 86156, Augsburg, Germany.

Introduction: Impaired wound healing, chronic wounds and extended soft tissue defects present a crucial problem in reconstructive surgery of the head and neck region, even more after radiation therapy. In such cases the standard is a prolonged open wound treatment. The negative pressure instillation therapy might present an alternative therapy option.

Material And Methods: In this study the effects of negative pressure instillation therapy on the healing of chronic wounds in 15 patients diagnosed with impaired wound healing were investigated. These based upon infected osteoradionecrosis and osteomyelitis of the jaw. The parameters investigated as markers of the therapeutic success were serum inflammatory parameters i.e. white blood cell counts, wound smear results and wound surface reduction.

Results: The use of negative pressure instillation therapy lead to a reduction of the bacterial load and formation of a stabile granulation tissue in all but one case. The mean inpatient time of the patients was 13.33 ± 4.62 days. Between 2 and 8 dressing changes were needed to reach clinical sufficient wound healing results. Secondary intention wound healing could be obtained in 14 out of 15 cases. The crucial part for the successful application was a watertight enoral suturing as oro-cutaneous fistulae were present in most cases.

Conclusion: The negative pressure instillation therapy poses a good treatment for wound healing problems and extended size soft tissue defects, even when oro-cutaneous fistulae were present. Especially in cases that contraindicate micro-vascular reconstruction, negative pressure instillation therapy could be a good alternative.
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http://dx.doi.org/10.1016/j.jcms.2018.12.006DOI Listing
March 2019

Correction to: Anatomical locations in the oral cavity where surgical resections of oral squamous cell carcinomas are associated with a close or positive margin-a retrospective study.

Clin Oral Investig 2019 01;23(1):509

Department of Oral and Maxillofacial Surgery, University of Erlangen-Nürnberg, Glückstrasse 11, 91054, Erlangen, Germany.

The following note was inadvertently omitted from the published paper: This work was performed in (partial) fulfillment of the requirements for the first author's obtaining the degree Dr. med. dent.
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http://dx.doi.org/10.1007/s00784-018-2781-7DOI Listing
January 2019

Impact of voxel size and scan time on the accuracy of three-dimensional radiological imaging data from cone-beam computed tomography.

J Craniomaxillofac Surg 2018 Dec 19;46(12):2190-2196. Epub 2018 Sep 19.

Department of Prosthodontics (Head: Professor Dr. M. Wichmann), Erlangen University Hospital, Glückstraße 11, 91054, Erlangen, Germany. Electronic address:

Purpose: Three-dimensional (3D) radiological imaging plays an important role in surgical planning used in modern dentistry. The aim of this study was to optimize imaging parameters with a special focus on voxel size and scan time.

Material And Methods: A virtual 3D master model of a macerated human skull was generated using an industrial optical noncontact white light scanner. The skull was X-rayed with cone-beam computed tomography that was applied using different settings for voxel size and acquisition time (voxel edge length of 0.3 mm, scan times 4.8 s and 8.9 s; voxel edge length of 0.2 mm, scan times 14.7 s and 26.9 s). The scan was repeated 10 times at each setting. The CBCT scans were converted into 3D virtual models (actual value), which were superimposed with the 3D master model (reference value) to detect absolute differences.

Results: The mean value of deviation increased with increasing voxel size and decreasing scan time. For a voxel edge length of 0.3 mm, the mean values of deviation were 0.33 mm and 0.22 mm with scan times of 4.8 s and 8.9 s, respectively. For a voxel edge length of 0.2 mm, the mean deviations were 0.16 mm and 0.14 mm with scan times of 14.7 s and 26.9 s, respectively.

Conclusions: When using small voxel sizes, the scan time does not have a significant impact on image accuracy and therefore the scan time can be shortened. However, for larger voxel sizes, shorter scan times can lead to increased inaccuracy.
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http://dx.doi.org/10.1016/j.jcms.2018.09.002DOI Listing
December 2018

Anatomical locations in the oral cavity where surgical resections of oral squamous cell carcinomas are associated with a close or positive margin-a retrospective study.

Clin Oral Investig 2018 May 23;22(4):1625-1630. Epub 2018 Mar 23.

Department of Oral and Maxillofacial Surgery, University of Erlangen-Nürnberg, Glückstrasse 11, 91054, Erlangen, Germany.

Objectives: This study aimed to identify anatomical areas where resections of oral squamous cell carcinomas (OSCC) are significantly associated with close or positive margins.

Materials And Methods: This retrospective study included 330 patients with a primary OSCC from 2010 to 2015. Patient and tumour data were categorised into three groups by R-status (R0 [clear], ≥ 5 mm, 185 patients [56.06%]; R1 [positive], < 1 mm, 24 patients [7.27%]; and R0 [close], 1-5 mm, 121 patients [36.67%]).

Results: Areas where resections were significantly associated with close or positive margins were the hard palate (p < 0.001), buccal mucosa (p = 0.03), floor of the mouth (p = 0.004), lower alveolar ridge (p = 0.01), retromolar triangle (p = 0.005), and dorsal tongue (p = 0.02).

Conclusions: Anatomical areas were identified in the oral cavity where it is challenging to resect OSCCs with an adequate safety margin.

Clinical Relevance: These results may enable surgeons to achieve a postulated safe distance during tumour resection, leading to a survival benefit for patients.
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http://dx.doi.org/10.1007/s00784-018-2424-zDOI Listing
May 2018

In-vitro evaluation of Polylactic acid (PLA) manufactured by fused deposition modeling.

J Biol Eng 2017 12;11:29. Epub 2017 Sep 12.

Department of Oral and Maxillofacial Surgery, University Hospital Erlangen, Glueckstrasse 11, 91054 Erlangen, Germany.

Background: With additive manufacturing (AM) individual and biocompatible implants can be generated by using suitable materials. The aim of this study was to investigate the biological effects of polylactic acid (PLA) manufactured by Fused Deposition Modeling (FDM) on osteoblasts in vitro according to European Norm / International Organization for Standardization 10,993-5.

Method: Human osteoblasts (hFOB 1.19) were seeded onto PLA samples produced by FDM and investigated for cell viability by fluorescence staining after 24 h. Cell proliferation was measured after 1, 3, 7 and 10 days by cell-counting and cell morphology was evaluated by scanning electron microscopy. For control, we used titanium samples and polystyrene (PS).

Results: Cell viability showed higher viability on PLA (95,3% ± 2.1%) than in control (91,7% ±2,7%). Cell proliferation was highest in the control group (polystyrene) and higher on PLA samples compared to the titanium samples. Scanning electron microscopy revealed homogenous covering of sample surface with regularly spread cells on PLA as well as on titanium.

Conclusion: The manufacturing of PLA discs from polylactic acid using FDM was successful. The in vitro investigation with human fetal osteoblasts showed no cytotoxic effects. Furthermore, FDM does not seem to alter biocompatibility of PLA. Nonetheless osteoblasts showed reduced growth on PLA compared to the polystyrene control within the cell experiments. This could be attributed to surface roughness and possible release of residual monomers. Those influences could be investigated in further studies and thus lead to improvement in the additive manufacturing process. In addition, further research focused on the effect of PLA on bone growth should follow. In summary, PLA processed in Fused Deposition Modelling seems to be an attractive material and method for reconstructive surgery because of their biocompatibility and the possibility to produce individually shaped scaffolds.
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http://dx.doi.org/10.1186/s13036-017-0073-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5594599PMC
September 2017

Does formalin fixation influence MSCT/CBCT accuracy?

Surg Radiol Anat 2018 Jan 21;40(1):31-37. Epub 2017 Aug 21.

Department of Prosthodontics, Erlangen University Hospital, Glueckstraße 11, 91054, Erlangen, Germany.

Purpose: Advanced imaging modalities, such as multi-slice computed tomography (MSCT) and cone beam computed tomography (CBCT), greatly facilitate diagnostic medicine. In radiological research, it is important to know how accurately a scanned object is visualized, and whether the methodology leads to image distortion. The objective of this study was to evaluate whether formalin fixation impacted the accuracy of virtual 3D bone models generated via CBCT and MSCT using a software-based evaluation method that excluded human measurement errors.

Methods: A head specimen, with and without formalin preservation, was subjected to MSCT and CBCT scans using the manufacturers' predefined scanning protocols. Digital models of the lower jaw were constructed and superimposed with a master model generated based on optical scanning with an industrial non-contact scanner. Means and standard deviations were calculated to assess accuracy, and a t test was used for comparisons between the fixed and unfixed specimens.

Results: The extent of discrepancy between the fixed and unfixed specimens was analyzed using a total of 200 points (n = 200) in each specimen state. The mean deviation between states was 0.01 mm for MSCT (at both 80 and 140 kV). Mean values from CBCT at 0.4 voxel did not differ between states.

Conclusions: Our results suggest that formalin fixation of an anatomical specimen does not substantially affect the accuracy of a three-dimensional image generated with CBCT and MSCT. Thus, fixed specimen can be used in future investigations of 3D models without concerns regarding the accuracy.
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http://dx.doi.org/10.1007/s00276-017-1908-xDOI Listing
January 2018

Chronic recurrent multifocal osteomyelitis in association with pyoderma gangraenosum.

BMC Oral Health 2016 Sep 1;16(1):85. Epub 2016 Sep 1.

Department of Oral and Maxillofacial Surgery, University of Erlangen-Nürnberg, Glückstrasse 11, 91054, Erlangen, Germany.

Background: Chronic recurrent multifocal osteomyelitis (CRMO) is a rare acquired inflammatory skeletal disorder of unknown origin. CRMO was first described by Gideon in 1972 and mainly affects children and young adults of female gender. The CRMO is part of the clinical picture of non-bacterial Osteomyelitis (NBO) and typically presents a relapsing recurring course with both remission and spontaneous exacerbation. CRMO is typically encountered in the limbs and the metaphysis of long bones in particular. Usually the clinical symptoms include painful swellings of the affected regions. This case report describes the rare case of a CRMO of the mandible in association with pyoderma gangraenosum.

Case Presentation: A 14-year old female caucasian patient, residing in the south of Germany, presented in the oncological outpatient clinic of our Department of Paediatrics and Adolescent Medicine in June 2014 complaining of increasing neck pain and progressive swelling at her left cheek ongoing for about 6 weeks. These symptoms had been occurring quarterly for 4 years, but had never been as pronounced. Blood biochemistry showed a moderately elevated CRP (35 mg/l) and a significantly increased blood sedimentation rate (BSR 48/120 mm). The panoramic radiograph, however, revealed a bone alteration in the left mandibular region. Further investigations confirmed the diagnosis of CRMO.

Conclusion: The present case underlines the fact that rare diseases might occasionally present with even more rare symptoms. These occasions can obviously be considered to present a considerable diagnostic challenge.
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http://dx.doi.org/10.1186/s12903-016-0275-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5009688PMC
September 2016

Development and validation of a classification and scoring system for the diagnosis of oral squamous cell carcinomas through confocal laser endomicroscopy.

J Transl Med 2016 06 3;14(1):159. Epub 2016 Jun 3.

Department of Oral and Maxillofacial Surgery, Friedrich-Alexander University Erlangen-Nürnberg (FAU), University Hospital Erlangen, Glückstraße 11, 91054, Erlangen, Germany.

Background: Confocal laser endomicroscopy (CLE) is an optical biopsy method allowing in vivo microscopic imaging at 1000-fold magnification. It was the aim to evaluate CLE in the human oral cavity for the differentiation of physiological/carcinomatous mucosa and to establish and validate, for the first time, a scoring system to facilitate CLE assessment.

Methods: The study consisted of 4 phases: (1) CLE-imaging (in vivo) was performed after the intravenous injection of fluorescein in patients with histologically confirmed carcinomatous oral mucosa; (2) CLE-experts (n = 3) verified the applicability of CLE in the oral cavity for the differentiation between physiological and cancerous tissue compared to the gold standard of histopathological assessment; (3) based on specific patterns of tissue changes, CLE-experts (n = 3) developed a classification and scoring system (DOC-Score) to simplify the diagnosis of oral squamous cell carcinomas; (4) validation of the newly developed DOC-Score by non-CLE-experts (n = 3); final statistical evaluation of their classification performance (comparison to the results of CLE-experts and the histopathological analyses).

Results: Experts acquired and edited 45 sequences (260 s) of physiological and 50 sequences (518 s) of carcinomatous mucosa (total: 95 sequences/778 s). All sequences were evaluated independently by experts and non-experts (based on the newly proposed classification system). Sensitivity (0.953) and specificity (0.889) of the diagnoses by experts as well as sensitivity (0.973) and specificity (0.881) of the non-expert ratings correlated well with the results of the present gold standard of tissue histopathology. Experts had a positive predictive value (PPV) of 0.905 and a negative predictive value (NPV) of 0.945. Non-experts reached a PPV of 0.901 and a NPV of 0.967 with the help of the DOC-Score. Inter-rater reliability (Fleiss` kappa) was 0.73 for experts and 0.814 for non-experts. The intra-rater reliability (Cronbach's alpha) of the experts was 0.989 and 0.884 for non-experts.

Conclusions: CLE is a suitable and valid method for experts to diagnose oral cancer. Using the DOC-Score system, an accurate chair-side diagnosis of oral cancer is feasible with comparable results to the gold standard of histopathology-even in daily clinical practice for non-experienced raters.
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http://dx.doi.org/10.1186/s12967-016-0919-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4891821PMC
June 2016

Peri-implant defect regeneration in the diabetic pig: A preclinical study.

J Craniomaxillofac Surg 2016 Jul 13;44(7):827-34. Epub 2016 Apr 13.

Department of Oral and Maxillofacial Surgery, University of Erlangen-Nuremberg, Glückstrasse 11, 91054 Erlangen, Germany. Electronic address:

Objectives: The study aims to establish a peri-implant dehiscence-type bone defect in a diabetic animal model of human bone repair and to quantify the influence of diabetes on peri-implant bone regeneration.

Material And Methods: Experimental diabetes was induced in three domestic pigs by streptozotocin. Three animals served as healthy controls. After 12 months four standardized peri-implant dehiscence bone defects were surgically created in the ramus mandibulae. The animals were sacrificed after 90 days. Samples were histologically analyzed to quantify new bone height (NBH), bone-to-implant-contact (BIC), area of newly formed bone (NFB), bone-density (BD), and bone mineralization (BM) in the prepared defect (-D) and in a local control region (-L).

Results: After 90 days, diabetic animals revealed a significantly lower BIC (p = 0.037) and BD (p = 0.041) in the defect area (-D). NBH and BM-D differences within the groups were not significant (p > 0.05). Significant more NFB was measured in the healthy control group (p = 0.046). In the region of local bone BIC-L was significant less in the diabetic group (p = 0.028). In the local control region BD-L and BM-L was lower in the diabetic group compared to the healthy control animals (p > 0.05).

Conclusion: Histological evidence indicates impaired peri-implant defect regeneration in a diabetic animal model.
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http://dx.doi.org/10.1016/j.jcms.2016.04.002DOI Listing
July 2016

The impact of different cone beam computed tomography and multi-slice computed tomography scan parameters on virtual three-dimensional model accuracy using a highly precise ex vivo evaluation method.

J Craniomaxillofac Surg 2016 May 13;44(5):632-6. Epub 2016 Feb 13.

Department of Oral and Maxillofacial Surgery (Head: Prof. Dr. Dr. Dr. h.c. F.W. Neukam), Erlangen University Hospital, Glückstrasse 11, 91054 Erlangen, Germany. Electronic address:

Objectives: Multi-slice computed tomography (MSCT) and cone beam computed tomography (CBCT) are indispensable imaging techniques in advanced medicine. The possibility of creating virtual and corporal three-dimensional (3D) models enables detailed planning in craniofacial and oral surgery. The objective of this study was to evaluate the impact of different scan protocols for CBCT and MSCT on virtual 3D model accuracy using a software-based evaluation method that excludes human measurement errors.

Material And Methods: MSCT and CBCT scans with different manufacturers' predefined scan protocols were obtained from a human lower jaw and were superimposed with a master model generated by an optical scan of an industrial noncontact scanner. To determine the accuracy, the mean and standard deviations were calculated, and t-tests were used for comparisons between the different settings.

Results: Averaged over 10 repeated X-ray scans per method and 19 measurement points per scan (n = 190), it was found that the MSCT scan protocol 140 kV delivered the most accurate virtual 3D model, with a mean deviation of 0.106 mm compared to the master model. Only the CBCT scans with 0.2-voxel resolution delivered a similar accurate 3D model (mean deviation 0.119 mm).

Conclusion: Within the limitations of this study, it was demonstrated that the accuracy of a 3D model of the lower jaw depends on the protocol used for MSCT and CBCT scans.
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http://dx.doi.org/10.1016/j.jcms.2016.02.005DOI Listing
May 2016

Case History Report: Immediate Rehabilitation with a Prefabricated Fibula Flap Following Removal of a Locally Aggressive Maxillary Tumor.

Int J Prosthodont 2016 Jan-Feb;29(1):53-8

The present clinical case history report describes an interdisciplinary treatment protocol that combines maxillary tumor resection with immediate reconstruction to achieve functional rehabilitation. A fibula flap that received four dental implants and a split-thickness graft epithelial layer was prefabricated for a 31-year-old man. The flap was designed so that it could be adapted to fit in different extents of tumor resection. Resection and immediate reconstruction were successfully performed 6 weeks after flap prefabrication, with the final bar-retained dental prosthesis delivered 4 weeks later.
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http://dx.doi.org/10.11607/ijp.4010DOI Listing
April 2016

A new, highly precise measurement technology for the in vitro evaluation of the accuracy of digital imaging data.

J Craniomaxillofac Surg 2015 Oct 25;43(8):1335-9. Epub 2015 Jun 25.

Department of Prosthodontics (Head: Prof. Dr. M. Wichmann), Erlangen University Hospital, Glückstrasse 11, 91054 Erlangen, Germany.

Objectives: Three-dimensional radiological imaging data play an increasingly role in planning, simulation, and navigation in oral and maxillofacial surgery. The aim of this study was to establish a new, highly precise, in vitro measurement technology for the evaluation of the geometric accuracy down to the micrometric range of digital imaging data.

Material And Methods: A macerated human mandible was scanned optically with an industrial, non-contact, white light scanner, and a three-dimensional (3D) model was obtained, which served as a master model. The mandible was then scanned 10 times by cone beam computed tomography (CBCT), and the generated 3D surface bone model was virtually compared with the master model. To evaluate the accuracy of the CBCT scans, the standard deviation and the intraclass coefficient were determined.

Results: A total of 19 measurement points in 10 CBCT scans were investigated, and showed an average value of 0.2676 mm with a standard deviation of 0.0593 mm. The standard error of the mean was 0.0043 mm. The intraclass correlation coefficient (ICC) within the 10 CBCT scans was 0.9416.

Conclusions: This highly precise measuring technology was demonstrated to be appropriate for the evaluation of the accuracy of digital imaging data, down to the micrometric scale. This method is able to exclude human measurement errors, as the software calculates the superimposition and deviation. Thus inaccuracies caused by measurement errors can be avoided. This method provides a highly precise determination of deviations of different CBCT parameters and 3D models for surgical, navigational, and diagnostic purposes. Thus, surgical procedures and the post-operative outcomes can be precisely simulated to benefit the patient.
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http://dx.doi.org/10.1016/j.jcms.2015.06.021DOI Listing
October 2015

Case report: Upper arm metastasis of an oral squamous cell carcinoma.

BMC Oral Health 2015 Feb 15;15:22. Epub 2015 Feb 15.

Department of Oral and Maxillofacial Surgery, University of Erlangen-Nürnberg, Glückstrasse 11, 91054, Erlangen, Germany.

Background: The Oral Squamous Cell Carcinoma (OSCC) frequently metastasizes lymphogenously. Haematogenous dissemination is less common. This report describes a rare case of a metastatic OSCC of the floor of the mouth to the patients' left upper arm. To our knowledge this is the first of such case described in the literature.

Case Presentation: Twelve months after R0 tumor resection surgery, including microvascular reconstruction of the lower jaw followed by adjuvant radiotherapy, the patient was admitted for osteosynthesis plates removal. During clinical examination a tumor located at his left upper arm was detected. According to the patient the tumor has demonstrated rapid growth. Macroscopic appearance and conventional imaging led to the differential diagnosis of an abscess. MR-imaging could not differentiate between a tumor of soft tissue origin and a metastasis. A biopsy was taken and the pathological examination confirmed the diagnosis of an OSCC metastasis. The postoperative interdisciplinary tumor board recommended radiation therapy.

Conclusion: Due to the fact that patients with regional lymph node metastases have a higher probability to develop distant metastasis a more detailed screening might be considered--especially when hemangiosis carcinomatosa was histologically or macroscopically found.
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http://dx.doi.org/10.1186/s12903-015-0007-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4348170PMC
February 2015

Dental treatment on a German warship during a three-month deployment.

J R Army Med Corps 2014 Mar 17;160(1):42-5. Epub 2013 Jul 17.

Army Medical Center, Bad Reichenhall, Germany.

Introduction: Despite routine dental screenings and treatments before military deployments, dental emergencies may arise due to acute infections, trauma or failed restorations. The purpose of this study is to evaluate the dental service during a three-month deployment on a German warship.

Methods: A retrospective analysis of dental attendances and treatments in a German naval task group of three ships with an average total of 650 soldiers. Diagnosis, treatments performed, percentage of emergencies, routine procedures and numbers of appointments were recorded.

Results: Out of 650 soldiers, there were 71 patients (10.92%) with a mean age of 25.1 ±5 .3 years. Out of 136 treatments, 17.65% were for emergency treatment, which is equivalent to 3.69% of all servicemen of the task group. Combining the reasons for dental emergencies, 95.84% were caused by caries.

Conclusions: The pre-screening of sailors before an overseas deployment is necessary to avoid severe dental treatments. Caries remains the main cause for dental emergencies, and medical doctors should be trained to treat caries lesions if a dentist is not on board.
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http://dx.doi.org/10.1136/jramc-2013-000063DOI Listing
March 2014

Morphological zeta-potential variation of nanoporous anodic alumina layers and cell adherence.

Acta Biomater 2014 Feb 29;10(2):968-74. Epub 2013 Sep 29.

Department of Materials Science (Glass and Ceramics), University of Erlangen-Nuernberg, Martens-str. 5, 91054 Erlangen, Germany.

Nanoscale surface modification of biomedical implant materials offers enhanced biological activity concerning protein adsorption and cell adherence. Nanoporous anodic alumina oxide (AAO) layers were prepared by electrochemical oxidation of thin Al-seed layers in 0.22 M C2H2O4, applying anodization voltages of 20-60 V. The AAO layers are characterized by a mean pore diameter varying from 15 to 40 nm, a mean pore distance of 40-130 nm, a total porosity of ≈ 10% and a thickness of 560 ± 40 nm. Zeta potential and isoelectric point (iep) were derived from streaming potential measurements and correlated to the topology variation of the nanoporous AAO layers. With decreasing pore diameter a shift of iep from ≈ 7.9 (pore diameter 40 nm) to ≈ 6.7 (pore diameter 15 nm) was observed. Plain alumina layers, however, possess an iep of ≈ 9. Compared to the plain alumina surface an enhanced adherence and activity of hFOB cells was observed on the nanoporous AAO after 24h culture with a maximum at a pore size of 40 nm. The topology-induced change of the electrochemical surface state may have a strong impact on protein adsorption as well as on cell adhesion, which offers a high potential for the development of bioactive AAO coatings on various biomaterial substrates.
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http://dx.doi.org/10.1016/j.actbio.2013.09.023DOI Listing
February 2014

The outcome after surgical therapy of bisphosphonate-associated osteonecrosis of the jaw--results of a clinical case series with an average follow-up of 20 months.

Clin Oral Investig 2014 May 29;18(4):1299-1304. Epub 2013 Aug 29.

Department of Oral and Maxillofacial Surgery, Friedrich-Alexander-University Erlangen-Nuremberg, Glückstrasse 11, 91054, Erlangen, Germany.

Objectives: The present case series evaluates the success rate of osteotomy and primary wound closure in patients with bisphosphonate-associated osteonecrosis of the jaw (BRONJ).

Materials And Methods: Eighty patients suffering from BRONJ were included in the study. All patients received intravenous bisphosphonate therapy and underwent osteotomy and primary wound closure according to a standardised protocol. After discharge, the patients were reviewed on a regular basis over an average time period of 20 months.

Results: During follow-up in 11 patients, a recurrence of BRONJ occurred in the former operation field. Seventeen patients died due to their underlying disease. The success rate of osteotomy and primary wound closure in the treatment of BRONJ was calculated at 84.2 % 20 months after surgery. The results showed non-significant difference concerning the outcome of surgery in the different clinical stages of BRONJ.

Conclusions: In accordance with previous studies, stage-independent osteotomy and primary wound closure combined with antibiotics shall be deemed a viable treatment option in patients suffering from BRONJ.

Clinical Relevance: With a high success rate, osteotomy in combination with primary wound closure seems to be a viable alternative to more conservative protocols in the treatment of BRONJ.
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http://dx.doi.org/10.1007/s00784-013-1092-2DOI Listing
May 2014

Mandibular reconstruction using intraoral microvascular anastomosis following removal of an ameloblastoma.

J Oral Maxillofac Surg 2013 Nov 16;71(11):1983-92. Epub 2013 Jul 16.

Associate Professor, Department of Oral and Maxillofacial Surgery, Erlangen University Hospital, Erlangen, Germany. Electronic address:

Ameloblastoma is a histologically benign, locally aggressive tumor arising from the odontogenic ectoderm. It accounts for 1% of all oral tumors and for 9% to 11% of all odontogenic tumors. In up to 96.6%, the tumor can be found in the mandible, predominantly in the molar region. High recurrence rates of up to 90% have been described with conservative treatment. Recurrences most often occur after 2 to 5 years. After radical resection, significantly lower recurrence rates have been reported, sometimes as low as 3.6%. As a consequence, when recurrence rate is the main concern, there is a tendency to prefer radical resection of the ameloblastoma. Microvascular segmental reconstruction of the mandible that uses an intraoral anastomosis technique has not been described in the current literature. Therefore, the present study aimed at extending the armamentarium of bony microvascular reconstruction in cases of segmental mandibulectomy by describing an intraoral microvascular anastomosing technique.
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http://dx.doi.org/10.1016/j.joms.2013.03.027DOI Listing
November 2013

Intraoral microvascular anastomosis for segmental mandibular reconstruction following removal of an ameloblastoma.

J Craniofac Surg 2013 May;24(3):e265-70

Department of Oral and Maxillofacial Surgery, Erlangen University Hospital, Erlangen, Germany.

Cases of immediate bony microvascular reconstruction following segmental mandibulectomy in children are hard to find in the current literature. Moreover, microvascular segmental mandibular reconstruction that adopts an intraoral anastomosis technique has not been described so far. Therefore, the present clinical report aims at extending the armamentarium of bony microvascular reconstruction in pediatric cases of segmental mandibulectomy by highlighting an intraoral microvascular anastomosing technique.A 6-year-old boy, who suffered from an ameloblastoma of the mural type in the mandible, received a radical segmental mandibular resection because of the high recurrence rate of this tumor entity. Immediate reconstruction was carried out with a fibular double-barrel graft. Microvascular anastomoses were performed in an end-to-end fashion with the facial artery and vein as recipient vessels. The postoperative course was uneventful. There was no impairment of speech, deglutition, mastication, and facial nerve function. The facial appearance remained unobtrusive. On removal of the reconstruction plate 3 months after the reconstruction procedure, bleeding from the reconstructed mandibular segment indicated vascularization of the graft.It seems that segmental mandibulectomy and simultaneous microvascular bony reconstruction do not necessarily lead to impaired function as far as speech, deglutition, and mastication are concerned. Instead, the intraoral anastomosis technique allows waiving extraoral skin incisions and subsequent scarring, leaving the facial appearance unchanged and unobtrusive. Especially, the potential risk of stigmatization of the patient is avoided. Therefore, decision making in the choice of 1 or the other reconstruction option following segmental mandibulectomy should always consider the adoption of an intraoral anastomosing technique.
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http://dx.doi.org/10.1097/SCS.0b013e31828cbe80DOI Listing
May 2013

Implants in bone: part I. A current overview about tissue response, surface modifications and future perspectives.

Oral Maxillofac Surg 2014 Sep 24;18(3):243-57. Epub 2013 Feb 24.

Mund-,Kiefer und Gesichtschirurgische Klinik Universitätsklinikum Erlangen, Glückstrasse 11, 91054, Erlangen, Germany,

Purpose: The aim of study paper is to present an overview of osseointegration of dental implants, focusing on tissue response, surface modifications and future perspective.

Discussion: Great progress has been made over the decades in the understanding of osseous peri-implant healing of dental implants, leading to the development of new implant materials and surfaces. However, failures and losses of implants are an indicator that there is room for improvement. Of particular importance is the understanding of the biological interaction between the implant and its surrounding bone.

Conclusion: The survival rates of dental implants in bone of over 90 % after 10 years show that they are an effective and well-established therapy option. However, new implant materials and surface modifications may be able to improve osseointegration of medical implants especially when the wound healing is compromised. Advanced techniques of evaluation are necessary to understand and validate osseointegration in these cases. An overview regarding the current state of the art in experimental evaluation of osseointegration of implants and implant material modifications will be given in Part II.
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http://dx.doi.org/10.1007/s10006-013-0398-1DOI Listing
September 2014

Implants in bone: part II. Research on implant osseointegration: material testing, mechanical testing, imaging and histoanalytical methods.

Oral Maxillofac Surg 2014 Dec 21;18(4):355-72. Epub 2013 Feb 21.

Mund-,Kiefer- und Gesichtschirurgische Klinik Universitätsklinikum Erlangen, Glückstrasse 11, 91054, Erlangen, Germany,

Purpose: In order to determine whether a newly developed implant material conforms to the requirements of biocompatibility, it must undergo rigorous testing. To correctly interpret the results of studies on implant material osseointegration, it is necessary to have a sound understanding of all the testing methods. The aim of this overview is to elucidate the methods that are used for the experimental evaluation of the osseointegration of implant materials.

Discussion: In recent decades, there has been a constant proliferation of new materials and surface modifications in the field of dental implants. This continuous development of innovative biomaterials requires a precise and detailed evaluation in terms of biocompatibility and implant healing before clinical use. The current gold standard is in vivo animal testing on well validated animal models. However, long-term outcome studies on patients have to follow to finally validate and show patient benefit.

Conclusion: No experimental set-up can provide answers for all possible research questions. However, a certain transferability of the results to humans might be possible if the experimental set-up is carefully chosen for the aspects and questions being investigated. To enhance the implant survival rate in the rising number of patients with chronic diseases which compromise wound healing and osseointegration, dental implant research on compromised animal models will further gain importance in future.
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http://dx.doi.org/10.1007/s10006-013-0397-2DOI Listing
December 2014

Nano-crystalline diamond-coated titanium dental implants - a histomorphometric study in adult domestic pigs.

J Craniomaxillofac Surg 2013 Sep 21;41(6):532-8. Epub 2012 Dec 21.

Department of Cranio-Maxillofacial and Oral Surgery, University Hospital of Zurich, Switzerland.

Promising biomaterial characteristics of diamond-coatings in biomedicine have been described in the literature. However, there is a lack of knowledge about implant osseointegration of this surface modification compared to the currently used sandblasted acid-etched Ti-Al6-V4 implants. The aim of this study was to investigate the osseointegration of microwave plasma-chemical-vapour deposition (MWP-CVD) diamond-coated Ti-Al6-V4 dental implants after healing periods of 2 and 5 months. Twenty-four MWP-CVD diamond-coated and 24 un-coated dental titanium-alloy implants (Ankylos(®)) were placed in the frontal skull of eight adult domestic pigs. To evaluate the effects of the nano-structured surfaces on bone formation, a histomorphometric analysis was performed after 2 and 5 months of implant healing. Histomorphometry analysed the bone-to-implant contact (BIC). No significant difference in BIC for the diamond-coated implants in comparison to reference implants could be observed for both healing periods. Scanning electron microscopy revealed an adequate interface between the bone and the diamond surface. No delamination or particle-dissociation due to shearing forces could be detected. In this study, diamond-coated dental titanium-alloy implants and sandblasted acid-etched implants showed a comparable degree of osseointegration.
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http://dx.doi.org/10.1016/j.jcms.2012.11.020DOI Listing
September 2013

The effect of current used bone substitution materials and platelet-rich plasma on periosteal cells by ectopic site implantation: an in-vivo pilot study.

J Craniomaxillofac Surg 2012 Jul 26;40(5):409-15. Epub 2011 Aug 26.

Department of Craniomaxillofacial and Oral Surgery (Head: Klaus Wilhelm Grätz, MD, DMD, PhD), University of Zurich, Frauenklinikstrasse 24, 8091 Zurich, Switzerland.

The aim of this study was to investigate de novo bone formation following ectopic site implantation of bone substitutes covered by periosteum, with and without the application of autologous platelet-rich plasma (PRP). Twenty-four weeks after subcutaneous implantation of various bone substitutes (bovine hydroxyapatite (bHAP), phycogenic hydroxyapatite (pHAP), and bioglass (BG)) in 35 mini-pigs, bone regeneration rates were compared microradiographically and histologically. Without PRP, bHAP showed a mean de novo bone formation of 32.41%±29.99, in contrast to the other substitute materials where no mineralization could be detected. In combination with PRP, in the bHAP (63.61%±12.98; p±0.03) and pHAP (34.37±29.38; p=0.015) group, significantly higher de novo bone formation was ascertained than without PRP. No ossification could be detected in the BG group. In conclusion, bHAP and pHAP bone substitutes in combination with PRP showed a significant positive effect on periosteal cells by de novo bone formation after ectopic, subcutaneous, low-vascular site implantation.
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http://dx.doi.org/10.1016/j.jcms.2011.07.012DOI Listing
July 2012

Diabetes mellitus negatively affects peri-implant bone formation in the diabetic domestic pig.

J Clin Periodontol 2011 Aug;38(8):771-9

Department of Oral and Maxillofacial Surgery, University of Erlangen-Nuremberg, Erlangen, Germany.

Aim: Diabetes mellitus is classified as a relative contraindication for implant treatment, and higher failure rates have been seen in diabetic patients. The aim of the present study was to investigate the effect of diabetes on peri-implant bone formation in an animal model of human bone repair.

Materials And Methods: Diabetes was induced by an intra-venous application of streptozotocin (90 mg/kg) in 15 domestic pigs. Implants were placed after significant histopathological changes in the hard and soft tissues were verified. The bone-implant contact (BIC), peri-implant bone mineral density (BMD), and expression of collagen type-I and osteocalcin proteins were qualitatively evaluated 4 and 12 weeks after implantation. Fifteen animals served as healthy controls.

Results: Diabetes caused pathological changes in the soft and hard tissues. The BIC and BMD were significantly reduced in the diabetic group after 4 and 12 weeks. Collagen type-I was increased in the diabetic group at both time points, whereas osteocalcin was reduced in the diabetic group.

Conclusions: Poorly controlled diabetes negatively affects peri-implant bone formation and bone mineralization. These findings have to be taken into consideration for diabetic patients with an indication for implant therapy.
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http://dx.doi.org/10.1111/j.1600-051X.2011.01746.xDOI Listing
August 2011

Guided bone regeneration in pig calvarial bone defects using autologous mesenchymal stem/progenitor cells - a comparison of different tissue sources.

J Craniomaxillofac Surg 2012 Jun 30;40(4):310-20. Epub 2011 Jun 30.

Department of Oral and Maxillofacial Surgery, University of Erlangen-Nuremberg, Erlangen, Germany.

Due to donor side morbidity and the absence of osteogenic properties in bone substitutes, there is a growing need for an alternative to traditional bone grafting within the scope of tissue engineering. This animal study was conducted to compare the in vivo osteogenic potential of adipose-derived (AD), periosteum-derived (PD) and bone marrow-derived (BM) mesenchymal stem/progenitor cells (MSC). Autologous mesenchymal stem/progenitor cells of named tissue origin were induced into osteogenic differentiation following in vitro cell expansion. Ex vivo cultivated cells were seeded on a collagen scaffold and subsequently added to freshly created monocortical calvarial bone defects in 21 domestic pigs. Pure collagen scaffold served as a control defect. The animals were sacrificed at specific time points and de novo bone formation was quantitatively analyzed by histomorphometry. Bone volume/total defect volume (BV/TV) and the mineralization rate of newly formed bone were compared among the groups. In the early stages of wound healing, up to 30 days, the test defects did not show better bone regeneration than those in the control defect, but the bone healing process in the test defects was accelerated in the later stage compared to those in the control defect. All the test defects showed complete osseous healing after 90 days compared to those in the control defect. During the observation period, no significant differences in BV/TV and mineralization of newly formed bone among the test defects were observed. Irrespective of the tissue sources of MSC, the speed and pattern of osseous healing after cell transplantations into monocortical bone defects were comparable. Our results indicate that the efficiency of autologous AD-MSC, PD-MSC and BM-MSC transplantation following ex vivo cell expansion is not significantly different for the guided regeneration of bone defects.
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http://dx.doi.org/10.1016/j.jcms.2011.05.004DOI Listing
June 2012

The diameter of anodic TiO2 nanotubes affects bone formation and correlates with the bone morphogenetic protein-2 expression in vivo.

Clin Oral Implants Res 2012 Mar 28;23(3):359-66. Epub 2011 Mar 28.

Department of Oral and Maxillofacial Surgery, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany.

Introduction: Recently, it has been demonstrated that the nanoscale environment is a critical factor for cellular behaviour. It has been shown that the diameter of TiO2 nanotube layers controls the cellular behaviour of cells involved in the bone-forming process in vitro. Therefore, the aim of the present study was to investigate the effects of the diameter of TiO2 nanotubes on peri-implant bone formation and the expression of bone matrix proteins in vivo.

Materials And Methods: Ninety experimental implants with a nanotube diameter ranging from 15 up to 100 nm were placed in the frontal skulls of six domestic pigs, whereas untreated implants served as controls. The bone-implant contact (BIC) as well as the expression of bone morphogenetic protein (BMP)-2, collagen type-I and osteocalcin were histomorphometrically and immunohistochemically analysed after 30 days.

Results: Evaluating the BIC, a significant higher value, could be found for the 50, 70 and 100 nm groups compared with the controls, whereas a correlation with the BMP-2 expression was present. The BMP-2 expression within the 50, 70 and 100 nm groups was statistically different compared with the control group. Significant difference was found for the osteocalcin expression in the 70 nm group. No statistical difference was found evaluating collagen type-I. SEM evaluation of the specimen surfaces revealed that the nanotube coatings do resist shearing forces evoked by implant insertion.

Conclusion: The nanotube diameter can be designed to support cellular functions of osteoblasts and osteoclasts in vivo, including differentiation and protein expression and therefore offer a powerful tool for the controlled formation of peri-implant bone around medical implant devices.
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http://dx.doi.org/10.1111/j.1600-0501.2010.02139.xDOI Listing
March 2012

The effect of combined delivery of recombinant human bone morphogenetic protein-2 and recombinant human vascular endothelial growth factor 165 from biomimetic calcium-phosphate-coated implants on osseointegration.

Clin Oral Implants Res 2011 Dec 21;22(12):1433-9. Epub 2011 Mar 21.

Department of Oral Surgery, Faculty of Dentistry, Istanbul University, Istanbul, Turkey.

Objectives: The delivery of growth factors for enhanced osseointegration depends on the effectiveness of the carrier systems at the bone-implant interface. This study evaluated the effect of solo and dual delivery of recombinant human bone morphogenetic protein-2 (rhBMP-2) and recombinant human vascular endothelial growth factor (rhVEGF(165) ) from biomimetically octacalcium phosphate-coated implants on osseointegration.

Materials And Methods: Biomimetic implants, bearing either a single growth factor (BMP or VEGF) or their combination (BMP+VEGF), were established, and compared with acid-etched (AE, control) and biomimetic implants without growth factor (CAP). Implants were placed into frontal skulls of nine domestic pigs. The quality of osseointegration was evaluated using microradiographic and histomorphometric analysis of bone formation inside four defined bone chambers of the experimental implant at 1, 2 and 4 weeks.

Results: Biomimetic implants, either with or without growth factor, showed enhanced bone volume density (BVD) values after 2 and 4 weeks. This enhancement was significant for the BMP and BMP+VEGF group compared with the control AE group after 2 weeks (P<0.05). All biomimetic calcium-phosphate (Ca-P) coatings exhibited significantly enhanced bone-implant contact (BIC) rates compared with the uncoated control surface after 2 weeks (P<0.05). However, the combined delivery of BMP-2 and VEGF did not significantly enhance BIC at the final observation period.

Conclusion: It was concluded that the combined delivery of BMP-2 and VEGF enhances BVD around implants, but not BIC. Therefore, it may be assumed that changes in the surface characteristics should be considered when designing growth factor-delivering surfaces.
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http://dx.doi.org/10.1111/j.1600-0501.2010.02133.xDOI Listing
December 2011
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