Ulrich Meyer

Publications of Ulrich Meyer

• [Evaluation of hyperbaric oxygen therapy in treatment of patients with osteomyelitis of the mandible]

  Authors: Jörg Handschel, Sabine Brüssermann, Rita Depprich, Michelle Ommerborn, Christian Naujoks, Norbert R Kübler, Ulrich Meyer

  Mund-, Kiefer- und Gesichtschirurgie : MKG. 12/2007; 11(5):285-90.

  BACKGROUND: Chronic osteomyelitis of the jaw is a relapsing disease with multiple treatment strategies described in the literature. Hyperbaric oxygen therapy is one of them. The purpose of this studyBACKGROUND: Chronic osteomyelitis of the jaw is a relapsing disease with multiple treatment strategies described in the literature. Hyperbaric oxygen therapy is one of them. The purpose of this study was to evaluate the clinical outcome of hyperbaric oxygen therapy in these patients. METHOD: All patients with a chronic osteomyelitis of the mandible who received in our department hyperbaric oxygen therapy between 2000 and 2004 were included in this study. The clinical outcome (lack of symptoms e.g. pain, swelling, etc.) was the pivotal evaluation parameter. All patients were divided in three groups according to their medical history. Group 1: All patients with osteomyelitis of the mandible, who received no treatment before. Group 2: All patients with one local relapse, who received only antimicrobial treatment. Group 3: Patients with at least one local relapse after antimicrobial and surgical treatment. RESULTS: 27 patients were evaluated in this study. Seven out of 13 patients in group 1 were relapse free after performing 40 hyperbaric oxygen therapies. However, only 4 of 9 patients in group 3 were relapse free after treatment. In group 2 the hyperbaric oxygen therapy was successful particularly in the younger patients (3 of 4). CONCLUSION: Adjuvant hyperbaric oxygen therapy was successful in the treatment of patients with chronic recurrent osteomyelitis of the mandible. Therefore, it is an treatment option which can avoid ablative surgery in some cases.

• Additional use of DNA-image cytometry improves the assessment of resection margins.

  Authors: Jörg Handschel, Döne Oz, Natalia Pomjanski, Rita Depprich, Michelle A Ommerborn, Stefan Braunstein, Norbert R Kübler, Ulrich Meyer, Alfred Böcking

  Journal of oral pathology & medicine : official publication of the International Association of Oral Pathologists and the American Academy of Oral Pathology. 10/2007; 36(8):472-5.

  BACKGROUND: Despite the histopathologic findings of tumor-free margins, patients with oral squamous cell carcinoma (SCC) often suffer from local tumor relapse. The purpose of this study was toBACKGROUND: Despite the histopathologic findings of tumor-free margins, patients with oral squamous cell carcinoma (SCC) often suffer from local tumor relapse. The purpose of this study was to determine the prognostic value of DNA-image cytometry in the assessment of resection margins. METHODS: DNA-image cytometry was performed in 40 SCC patients with histologically tumor-free resection margins. The follow-up period since the tumor resection was at least 3 years. RESULTS: Twenty patients showed a locoregional relapse of the SCC. Fourteen of these patients had aneuploid cells in DNA-image cytometry. Two patients who were relapse-free revealed aneuploid cells too. The sensitivity of the adjuvant use of DNA-image cytometry was 70% and the positive predictive value was 87.5%. CONCLUSIONS: The additional use of DNA-image cytometry is a reasonable tool for the assessment of the resection margins of SCCs. DNA-image cytometry could help to find the appropriate treatment option for the patients and thus might improve their prognosis.

• Treatment of hemimandibular hyperplasia: the biological basis of condylectomy.

  Authors: Carsten Lippold, Birgit Kruse-Losler, Gholamreza Danesh, Ulrich Joos, Ulrich Meyer

  The British journal of oral & maxillofacial surgery. 08/2007; 45(5):353-60.

  Treatments to correct skeletal deformities in patients with hemimandibular hyperplasia differ, particularly about the age at which the operation is done and the operation itself. To some extent, theTreatments to correct skeletal deformities in patients with hemimandibular hyperplasia differ, particularly about the age at which the operation is done and the operation itself. To some extent, the differences can be attributed to the unknown biological basis of disease. The aim of the present study was to evaluate clinically the outcome of a rationale for the operation based on condylectomy on the affected side. Histological, radiological, and nuclear methods were used to get a more detailed insight into the reason for the operation. Six patients with hemimandibular hyperplasia were treated by a combined orthodontic-maxillofacial protocol. All patients had the affected joint removed. The histological morphology of each condylar specimen was compared with the bone scintigraphy to try and find a correlation between the methods. The clinical evaluation showed morphological and functional rehabilitation of all six patients. During the 2-year follow-up, all patients had stable symmetrical mandibles with no disturbance of temporomandibular function. Remodelling of the joint and the destruction of the cartilaginous layer was accompanied by much bone scintigraphic activity. We conclude that condylectomy can correct hemimandibular hyperplasia, even in patients with active condylar growth, by removing the underlying disease.

• Success rate of mini- and micro-implants used for orthodontic anchorage: a prospective clinical study.

  Authors: Dirk Wiechmann, Ulrich Meyer, André Büchter

  Clinical oral implants research. 05/2007; 18(2):263-7.

  OBJECTIVES: Whereas micro-implants have become a useful alternative as orthodontic anchorage elements in orthodontics, less is known about the clinical effectiveness of micro-implants. The aim ofOBJECTIVES: Whereas micro-implants have become a useful alternative as orthodontic anchorage elements in orthodontics, less is known about the clinical effectiveness of micro-implants. The aim of this prospective clinical study was to evaluate the success rate of micro-implants used for orthodontic anchorage. MATERIAL AND METHODS: A total of 133 mini-implants (79 Abso Anchor, 54 Dual Top implants) placed in 49 patients to support orthodontic tooth movements were examined in the study. The majority of the implants were placed in the maxilla (82), followed by the vestibular (42) and lingual (nine) aspect of the mandible. RESULTS: An overall cumulative survival rate of 86.8% (102/133) was found by Kaplan-Meier analysis. The failure rate between Dual Top implants (13%) and Abso Anchor implants (30.4%) differed significantly (P=0.0196; log-rank test). The cumulative failure rate of implants was found to be significantly higher when implants were placed in the lingual aspect of the mandible compared with the other localizations (P=0.0011; log-rank test). Clinical evaluation revealed successful dental movements when implants remained stable during the orthodontic therapy. CONCLUSIONS: The present results confirm the effectiveness of orthodontic micro-implants used as anchorage elements.

• Trick or treat?

  Authors: Murat Cehreli, Zafer Cehreli, Thomas Stamm, Ulrich Meyer, Hans-Peter Wiesmann

  Head & face medicine. 02/2007; 3:22.

  The purpose of this article is to draw attention to current transgressions in scientific writing and to promote commitment to ethical standards and good science. All participants of any researchThe purpose of this article is to draw attention to current transgressions in scientific writing and to promote commitment to ethical standards and good science. All participants of any research project, particularly under interdiciplinary team approach, should not only play an active role on the management and carrying out of their study but also ensure that their study is not fraudulent. Manuscript fabrication, data and/or figure manupilation, piracy (plagiarism), sloppy research, and transgressions in authorship are reasons for loss of scientific value and records, retraction of articles, and application of a variety of sanctions.

• Dentin dysplasia type I: a challenge for treatment with dental implants.

  Authors: Rita A Depprich, Michelle A Ommerborn, Jörg GK Handschel, Christian D Naujoks, Ulrich Meyer, Norbert R Kübler

  Head & face medicine. 02/2007; 3:31.

  ABSTRACT: BACKGROUND: Dentin dysplasia type I is characterized by a defect of dentin development with clinical normal appearance of the permanent teeth but no or only rudimentary root formation.ABSTRACT: BACKGROUND: Dentin dysplasia type I is characterized by a defect of dentin development with clinical normal appearance of the permanent teeth but no or only rudimentary root formation. Early loss of all teeth and concomitant underdevelopment of the jaws are challenging for successful treatment with dental implants. METHODS: A combination of sinus lifting and onlay bone augmentation based on treatment planning using stereolithographic templates was used in a patient with dentin dysplasia type I to rehabilitate the masticatory function. RESULTS: (i) a predisposition for an increased and accelerated bone resorption was observed in our patient, (ii) bone augmentation was successful using a mixture of allogenic graft material with autogenous bone preventing fast bone resorption, (iii) surgical planning, based on stereolithographic models and surgical templates, facilitated the accurate placement of dental implants. CONCLUSION: Bony augmentation and elaborate treatment planning is helpful for oral rehabilitation of patients with dentin dysplasia type I.

• Perioperative complications in infant cleft repair.

  Authors: Thomas Fillies, Christoph Homann, Ulrich Meyer, Alexander Reich, Ulrich Joos, Richard Werkmeister

  Head & face medicine. 02/2007; 3:9.

  BACKGROUND: Cleft surgery in infants includes special risks due to the kind of the malformation. These risks can be attributed in part to the age and the weight of the patient. Whereas a lot ofBACKGROUND: Cleft surgery in infants includes special risks due to the kind of the malformation. These risks can be attributed in part to the age and the weight of the patient. Whereas a lot of studies investigated the long-term facial outcome of cleft surgery depending on the age at operation, less is known about the complications arising during a cleft surgery in early infancy. METHODS: We investigated the incidence and severity of perioperative complications in 174 infants undergoing primary cleft surgery. The severity and the complications were recorded during the intraoperative and the early postoperative period according to the classification by Cohen. RESULTS: Our study revealed that minor complications occurred in 50 patients. Severe complications were observed during 13 operations. There was no fatal complication in the perioperative period. The risk of complications was found to be directly correlated to the body weight at the time of the surgery. Most of the problems appeared intraoperatively, but they were also followed by complications immediately after the extubation. CONCLUSION: In conclusion, cleft surgery in infancy is accompanied by frequent and sometimes severe perioperative complications that may be attributed to this special surgical field.

• The spectrum of Apert syndrome: phenotype, particularities in orthodontic treatment, and characteristics of orthognathic surgery.

  Authors: Ariane Hohoff, Ulrich Joos, Ulrich Meyer, Ulrike Ehmer, Thomas Stamm

  Head & face medicine. 02/2007; 3:10.

  In the PubMed accessible literature, information on the characteristics of interdisciplinary orthodontic and surgical treatment of patients with Apert syndrome is rare. The aim of the present articleIn the PubMed accessible literature, information on the characteristics of interdisciplinary orthodontic and surgical treatment of patients with Apert syndrome is rare. The aim of the present article is threefold: (1) to show the spectrum of the phenotype, in order (2) to elucidate the scope of hindrances to orthodontic treatment, and (3) to demonstrate the problems of surgery and interdisciplinary approach.Children and adolescents who were born in 1985 or later, who were diagnosed with Apert syndrome, and who sought consultation or treatment at the Departments of Orthodontics or Craniomaxillofacial Surgery at the Dental School of the University Hospital of Münster (n = 22; 9 male, 13 female) were screened. Exemplarily, three of these patients (2 male, 1 female), seeking interdisciplinary (both orthodontic and surgical treatment) are presented. Orthodontic treatment before surgery was performed by one experienced orthodontist (AH), and orthognathic surgery was performed by one experienced surgeon (UJ), who diagnosed the syndrome according to the criteria listed in OMIM. In the sagittal plane, the patients suffered from a mild to a very severe Angle Class III malocclusion, which was sometimes compensated by the inclination of the lower incisors; in the vertical dimension from an open bite; and transversally from a single tooth in crossbite to a circular crossbite. All patients showed dentitio tarda, some impaction, partial eruption, idopathic root resorption, transposition or other aberrations in the position of the tooth germs, and severe crowding, with sometimes parallel molar tooth buds in each quarter of the upper jaw.Because of the severity of malocclusion, orthodontic treatment needed to be performed with fixed appliances, and mainly with superelastic wires. The therapy was hampered with respect to positioning of bands and brackets because of incomplete tooth eruption, dense gingiva, and mucopolysaccharide ridges. Some teeth did not move, or moved insufficiently (especially with respect to rotations and torque) irrespective of surgical procedures or orthodontic mechanics and materials applied, and without prognostic factors indicating these problems. Establishing occlusal contact of all teeth was difficult. Tooth movement was generally retarded, increasing the duration of orthodontic treatment. Planning of extractions was different from that of patients without this syndrome.In one patient, the sole surgical procedure after orthodontic treatment with fixed appliances in the maxilla and mandible was a genioplasty. Most patients needed two- jaw surgery (bilateral sagittal split osteotomy [BSSO] with mandibular setback and distraction in the maxilla). During the period of distraction, the orthodontist guided the maxilla into final position by means of bite planes and intermaxillary elastics.To our knowledge, this is the first article in the PubMed accessible literature describing the problems with respect to interdisciplinary orthodontic and surgical procedures. Although the treatment results are not perfect, patients undergoing these procedures benefit esthetically to a high degree.Patients need to be informed with respect to the different kinds of extractions that need to be performed, the increased treatment time, and the results, which may be reached using realistic expectations.

• Sinus lifting before Le Fort I maxillary osteotomy: a suitable method for oral rehabilitation of edentulous patients with skeletal class-III conditions: review of the literature and report of a case.

  Authors: Rita A Depprich, Jörg G K Handschel, Christian Naujoks, Tobias Hahn, Ulrich Meyer, Norbert R Kübler

  Head & face medicine. 02/2007; 3:2.

  BACKGROUND: Functional rehabilitation of patients afflicted with severe mandibular and maxillary alveolar atrophy might be challenging especially in malformed patients. METHODS: Treatment planningBACKGROUND: Functional rehabilitation of patients afflicted with severe mandibular and maxillary alveolar atrophy might be challenging especially in malformed patients. METHODS: Treatment planning using sinus lifting and implant placement before Le Fort I maxillary osteotomy in a patient with severe mandibular and posterior maxillary alveolar atrophy and skeletal class-III conditions due to cleft palate are described. RESULTS: A full functional and esthetic rehabilitation of the patient was achieved by a stepwise surgical approach performed through sinus lifting as the primary approach followed by implant placement and subsequent Le Fort I maxillary osteotomy to correct the maxillo-mandibular relation. CONCLUSION: Stabilisation of the maxillary complex by a sinus lifting procedure in combination with computer aided implant placement as preorthodontic planning procedure before Le Fort I maxillary osteotomy seems to be suitable in order to allow ideal oral rehabilitation especially in malformed patients.

• Prospects of micromass culture technology in tissue engineering.

  Authors: Jörg G K Handschel, Rita A Depprich, Norbert R Kübler, Hans-Peter Wiesmann, Michelle Ommerborn, Ulrich Meyer

  Head & face medicine. 02/2007; 3:4.

  Tissue engineering of bone and cartilage tissue for subsequent implantation is of growing interest in cranio- and maxillofacial surgery. Commonly it is performed by using cells coaxed with scaffolds.Tissue engineering of bone and cartilage tissue for subsequent implantation is of growing interest in cranio- and maxillofacial surgery. Commonly it is performed by using cells coaxed with scaffolds. Recently, there is a controversy concerning the use of artificial scaffolds compared to the use of a natural matrix. Therefore, new approaches called micromass technology have been invented to overcome these problems by avoiding the need for scaffolds. Technically, cells are dissociated and the dispersed cells are then reaggregated into cellular spheres. The micromass technology approach enables investigators to follow tissue formation from single cell sources to organised spheres in a controlled environment. Thus, the inherent fundamentals of tissue engineering are better revealed. Additionally, as the newly formed tissue is devoid of an artificial material, it resembles more closely the in vivo situation. The purpose of this review is to provide an insight into the fundamentals and the technique of micromass cell culture used to study bone tissue engineering.

• Sinus lifting before Le Fort I maxillary osteotomy: a suitable method for oral rehabilitation of edentulous patients with skelettal class-III conditions: review of the literature and report of a case

  Authors: Rita Depprich, Jörg Handschel, Christian Naujoks, Tobias Hahn, Ulrich Meyer, Norbert Kübler

  Head & Face Medicine. 01/2007;

  Abstract Background Functional rehabilitation of patients afflicted with severe mandibular and maxillary alveolar atrophy might be challenging especially in malformed patients. Methods TreatmentAbstract Background Functional rehabilitation of patients afflicted with severe mandibular and maxillary alveolar atrophy might be challenging especially in malformed patients. Methods Treatment planning using sinus lifting and implant placement before Le Fort I maxillary osteotomy in a patient with severe mandibular and posterior maxillary alveolar atrophy and skelettal class-III conditions due to cleft palate are described. Results A full functional and esthetic rehabilitation of the patient was achieved by a stepwise surgical approach performed through sinus lifting as the primary approach followed by implant placement and subsequent Le Fort I maxillary osteotomy to correct the maxillo-mandibular relation. Conclusion Stabilisation of the maxillary complex by a sinus lifting procedure in combination with computer aided implant placement as preorthodontic planning procedure before Le Fort I maxillary osteotomy seems to be suitable in order to allow ideal oral rehabilitation especially in malformed patients.

• Prospects of micromass culture technology in tissue engineering

  Authors: Jörg Handschel, Rita Depprich, Norbert Kübler, Hans-Peter Wiesmann, Michelle Ommerborn, Ulrich Meyer

  Head & Face Medicine. 01/2007;

  Abstract Tissue engineering of bone and cartilage tissue for subsequent implantation is of growing interest in cranio- and maxillofacial surgery. Commonly it is performed by using cells coaxed withAbstract Tissue engineering of bone and cartilage tissue for subsequent implantation is of growing interest in cranio- and maxillofacial surgery. Commonly it is performed by using cells coaxed with scaffolds. Recently, there is a controversy concerning the use of artificial scaffolds compared to the use of a natural matrix. Therefore, new approaches called micromass technology have been invented to overcome these problems by avoiding the need for scaffolds. Technically, cells are dissociated and the dispersed cells are then reaggregated into cellular spheres. The micromass technology approach enables investigators to follow tissue formation from single cell sources to organised spheres in a controlled environment. Thus, the inherent fundamentals of tissue engineering are better revealed. Additionally, as the newly formed tissue is devoid of an artificial material, it resembles more closely the in vivo situation. The purpose of this review is to provide an insight into the fundamentals and the technique of micromass cell culture used to study bone tissue engineering.

• Dentin dysplasia type I: a challenge for treatment with dental implants

  Authors: Rita Depprich, Michelle Ommerborn, Jörg Handschel, Christian Naujoks, Ulrich Meyer, Norbert Kübler

  Head & Face Medicine. 01/2007;

  Abstract Background Dentin dysplasia type I is characterized by a defect of dentin development with clinical normal appearance of the permanent teeth but no or only rudimentary root formation.Abstract Background Dentin dysplasia type I is characterized by a defect of dentin development with clinical normal appearance of the permanent teeth but no or only rudimentary root formation. Early loss of all teeth and concomitant underdevelopment of the jaws are challenging for successful treatment with dental implants. Methods A combination of sinus lifting and onlay bone augmentation based on treatment planning using stereolithographic templates was used in a patient with dentin dysplasia type I to rehabilitate the masticatory function. Results (i) a predisposition for an increased and accelerated bone resorption was observed in our patient, (ii) bone augmentation was successful using a mixture of allogenic graft material with autogenous bone preventing fast bone resorption, (iii) surgical planning, based on stereolithographic models and surgical templates, facilitated the accurate placement of dental implants. Conclusion Bony augmentation and elaborate treatment planning is helpful for oral rehabilitation of patients with dentin dysplasia type I.

• A retrospective analysis of submissions, acceptance rate, open peer review operations, and prepublication bias of the multidisciplinary open access journal Head & Face Medicine.

  Authors: Thomas Stamm, Ulrich Meyer, Hans-Peter Wiesmann, Johannes Kleinheinz, Murat Cehreli, Zafer C Cehreli

  Head & face medicine. 01/2007; 3:27.

  BACKGROUND: Head & Face Medicine (HFM) was launched in August 2005 to provide multidisciplinary science in the field of head and face disorders with an open access and open peer review publicationBACKGROUND: Head & Face Medicine (HFM) was launched in August 2005 to provide multidisciplinary science in the field of head and face disorders with an open access and open peer review publication platform. The objective of this study is to evaluate the characteristics of submissions, the effectiveness of open peer reviewing, and factors biasing the acceptance or rejection of submitted manuscripts. METHODS: A 1-year period of submissions and all concomitant journal operations were retrospectively analyzed. The analysis included submission rate, reviewer rate, acceptance rate, article type, and differences in duration for peer reviewing, final decision, publishing, and PubMed inclusion. Statistical analysis included Mann-Whitney U test, Chi-square test, regression analysis, and binary logistic regression. RESULTS: HFM received 126 articles (10.5 articles/month) for consideration in the first year. Submissions have been increasing, but not significantly over time. Peer reviewing was completed for 82 articles and resulted in an acceptance rate of 48.8%. In total, 431 peer reviewers were invited (5.3/manuscript), of which 40.4% agreed to review. The mean peer review time was 37.8 days. The mean time between submission and acceptance (including time for revision) was 95.9 days. Accepted papers were published on average 99.3 days after submission. The mean time between manuscript submission and PubMed inclusion was 101.3 days. The main article types submitted to HFM were original research, reviews, and case reports. The article type had no influence on rejection or acceptance. The variable 'number of invited reviewers' was the only significant (p < 0.05) predictor for rejection of manuscripts. CONCLUSION: The positive trend in submissions confirms the need for publication platforms for multidisciplinary science. HFM's peer review time comes in shorter than the 6-weeks turnaround time the Editors set themselves as the maximum. Rejection of manuscripts was associated with the number of invited reviewers. None of the other parameters tested had any effect on the final decision. Thus, HFM's ethical policy, which is based on Open Access, Open Peer, and transparency of journal operations, is free of 'editorial bias' in accepting manuscripts. ORIGINAL DATA: Provided as a downloadable tab-delimited text file (URL and variable code available under section 'additional files').

• Load-related bone modelling at the interface of orthodontic micro-implants.

  Authors: André Büchter, Dirk Wiechmann, Christoph Gaertner, Marc Hendrik, Martin Vogeler, Hans-Peter Wiesmann, Josef Piffko, Ulrich Meyer

  Clinical oral implants research. 01/2007; 17(6):714-22.

  The purpose of this study was to determine the interface reaction of two different titanium micro-implant systems activated with different load regimens. A total of 200 micro-implants (100 AbsoThe purpose of this study was to determine the interface reaction of two different titanium micro-implant systems activated with different load regimens. A total of 200 micro-implants (100 Abso Anchor and 100 Dual Top) were placed in the mandible of eight Göttinger minipigs. Two implants each were immediately loaded in the opposite direction by various forces (100, 300 or 500 cN) through tension coils. Three different distances between the neck of the implant and the bone rim (1, 2, 3 mm) were used. The loads provided by superelastic tension coils (which are known to develop a virtually constant force) led to a range of tip moments 0-900 cN mm at the neck of implants. Non-loaded implants were used as a reference. Bone tissue responses were evaluated by histology, histomorphometry and scanning electron microscopy after 22 and 70 days of loading. Implant loosening was present in the groups where the load reached 900 cN mm. No movement of implants through the bone was found in the experimental groups, for any of the applied loads. A direct bone-to-implant contact to various extents was observed at differently loaded implants. Ultrastructural analysis confirmed the clinical and histological finding that implants (except when loaded at 900 cN mm) were well osseointegrated after 22 days. An increase in the bone-to-implant contact ratio was observed during the experimental period in the coronal part of the implants in most experimental groups. The difference reached a level of statistical significance at 500 cN mm (Abso Anchor) and 600 cN mm (Dual Top). We conclude that micro-implants can not only be loaded immediately without impairment of implant stability but many enhance bone formation at the interface when the load-related biomechanics do not exceed an upper limit of tip moment at the bone rim.

• Fast element mapping of titanium wear around implants of different surface structures.

  Authors: Ulrich Meyer, Martin Bühner, Andre Büchter, Birgit Kruse-Lösler, Thomas Stamm, Hans-Peter Wiesmann

  Clinical oral implants research. 05/2006; 17(2):206-11.

  The effect of unintended titanium release around oral implants remains a biological concern. The current study was undertaken to evaluate a new detection system of element mapping in biologicalThe effect of unintended titanium release around oral implants remains a biological concern. The current study was undertaken to evaluate a new detection system of element mapping in biological probes. A new scanning electron microscopy-energy dispersive spectroscopy detection method was used to map the features of titanium contamination in peri-implant bone around implants with different surface structures. The amount of titanium wear was highest adjacent to titanium-plasma-sprayed surfaces, followed by sandblastered large grid acid-etched and smooth surfaces. A high sensitivity of titanium detection over large areas of bone tissue was observed. A high spatial resolution of titanium wear particles (20 nm) could be reached and correlated to the ultrastructural morphological features of peri-implant tissue. Cells adjacent to titanium wear revealed no signs of morphological alterations on a nanoscale level at early periods of implant/bone interaction. The new technique may serve as a fast and effective tool to evaluate titanium release effects in biological probes.

• Objective growth monitoring of the maxilla in full term infants.

  Authors: Ariane Hohoff, Thomas Stamm, Ulrich Meyer, Dirk Wiechmann, Ulrike Ehmer

  Archives of oral biology. 04/2006; 51(3):222-35.

  OBJECTIVE: To develop a non-invasive method for longitudinal maxillary volume measurements and to provide first normative data. DESIGN: Thirty-four healthy infants served as a gold standard for aOBJECTIVE: To develop a non-invasive method for longitudinal maxillary volume measurements and to provide first normative data. DESIGN: Thirty-four healthy infants served as a gold standard for a growing population sample. Alginate impressions were taken of the upper jaw within the first week after birth, and consecutively at different stages of development. The plaster casts were digitised by an optical scanner generating a high resolution polygon mesh of each object. The digital models were aligned to a reference coordinate system with an iterative, landmark-independent procedure. Biometric linear and volume measurements were obtained by using feature-dependent calculations independent of landmark placements. Intra-investigator reproducibility was tested by repeated alignments and measurements of 30 randomly selected casts. To assess the effect of mesh resolution, the reproducibility test was repeated with low resolution models. The method was proved to be valid on the defined gold standard consisting of 96 consecutive edentulous casts. RESULTS: Feature-dependent, linear distances are less error prone (0.56-2.66%) compared to subjectively determined measurements (0.88-3.65%). The same applies to feature-dependent volume calculations (4.34%) compared to subjectively determined volumes (4.95%). Mesh resolution shows an effect (p<or=0.001) only on two linear measurements: palatal depth and palatal length. Growth of the individuals in the population sample was evidently confirmed by the maxillary volume measurements (asymptotic pattern) and by comparisons of head circumference (proportional pattern). CONCLUSION: The described method is non-invasive, precise and without any risk for the infant. Maxillary volume calculation could serve as an important biometric measurement for bone growth evaluation.

• New paradigm in implant osseointegration.

  Authors: Ulrich Joos, Ulrich Meyer

  Head & face medicine. 02/2006; 2:19.

  During the last years, implant dentistry has seen an dramatic increase as a treatment option in oral rehabilitation. This is based to a large extent on scientific advances and clinical improvementsDuring the last years, implant dentistry has seen an dramatic increase as a treatment option in oral rehabilitation. This is based to a large extent on scientific advances and clinical improvements in implantology. The extension of indications has broadened the opportunities to rehabilitate patients that were formerly considered to possess restricted indications to place implants. Additionally, patient desires (high aesthetic demands, fast prosthetic rehabilitation) were placed more in focus, resulting in new approaches in implant dentistry. As a result, the scientific and clinical community has reached high standards and at the same time has founded the basis for new opportunities in implantology. The advances are mirrored by a high number of high quality scientific papers, published in conventional and open-access journals. A major shift has thereby been observed in the understanding of implant healing, leading the basis for new implant systems that allow fast rehabilitation protocols. The term osseointegration needs a new understanding since an immediate osseointegration state can be present under distinct conditions.

• Biological and biomechanical evaluation of interface reaction at conical screw-type implants.

  Authors: Andre Büchter, Ulrich Joos, Hans-Peter Wiesmann, László Seper, Ulrich Meyer

  Head & face medicine. 02/2006; 2(1):5.

  ABSTRACT : BACKGROUND : Initial stability of the implant is, in effect, one of the fundamental criteria for obtaining long-term osseointegration. Achieving implant stability depends on theABSTRACT : BACKGROUND : Initial stability of the implant is, in effect, one of the fundamental criteria for obtaining long-term osseointegration. Achieving implant stability depends on the implant-bone relation, the surgical technique and on the microscopic and macroscopic morphology of the implant used. A newly designed parabolic screw-type dental implant system was tested in vivo for early stages of interface reaction at the implant surface. METHODS : A total of 40 implants were placed into the cranial and caudal part of the tibia in eight male Göttinger minipigs. Resonance frequency measurements (RFM) were made on each implant at the time of fixture placement, 7 days and 28 days thereafter in all animals. Block biopsies were harvested 7 and 28 days (four animals each) following surgery. Biomechanical testing, removable torque tests (RTV), resonance frequency analysis; histological and histomorphometric analysis as well as ultrastructural investigations (scanning electron microscopy (SEM)) were performed. RESULTS : Implant stability in respect to the measured RTV and RFM-levels were found to be high after 7 days of implants osseointegration and remained at this level during the experimented course. Additionally, RFM level demonstrated no alteration towards baseline levels during the osseointegration. No significant increase or decrease in the mean RFM (6029 Hz; 6256 Hz and 5885 Hz after 0-, 7- and 28 days) were observed. The removal torque values show after 7 and 28 days no significant difference. SEM analysis demonstrated a direct bone to implant contact over the whole implant surface. The bone-to-implant contact ratio increased from 35.8 +/- 7.2% to 46.3 +/- 17.7% over time (p = 0,146). CONCLUSION : The results of this study indicate primary stability of implants which osseointegrated with an intimate bone contact over the whole length of the implant.

• Interface reaction at dental implants inserted in condensed bone.

  Authors: André Büchter, Johannes Kleinheinz, Hans-Peter Wiesmann, Mythili Jayaranan, Ulrich Joos, Ulrich Meyer

  Clinical oral implants research. 11/2005; 16(5):509-17.

  PURPOSE: The influence of the osteotome technique on the interface reaction of cylinder implants (SLA, ITI) was compared with the interface reaction of conventional implant insertion in an animalPURPOSE: The influence of the osteotome technique on the interface reaction of cylinder implants (SLA, ITI) was compared with the interface reaction of conventional implant insertion in an animal model. MATERIAL AND METHODS: A total of 64 implants were placed in the cranial and caudal tibia of 8 Göttinger minipigs. The implant site was prepared either by a conventional technique with drills (control group A) or by the osteotome technique (experimental group B). Bone tissue responses were evaluated by histomorphometry, fluorescence microscopy and scanning electron microscopy after 7 and 28 days of osseointegration. RESULTS: The average initial (7 days) bone-to-implant contact ratio was not statistically significantly different for the osteotome technique (35.88+/-2.94%) than for the control group (43.78+/-3.39%, P<0.095). After 28 days, the bone-to-implant contact ratio became statistically significantly higher when implants were inserted by conventional preparation (44.81+/-3.07% (group B), 63.47+/-4.87% (group A), P=0.003). Whereas fluorescence and immunhistologic examination revealed new bone formation with osteocalcin deposition directly at the implant surface in both groups, the extent of direct bone/implant contact was enhanced in conventionally prepared implant sites. SEM analysis confirmed an intimate bone to implant bond without fibrous tissue formation in places of direct contact at an ultrastructured level. CONCLUSION: Implant placement in conventionally prepared implantation sites is accompanied by an improved interface formation at an early stage of implantation.