1. |
- Danz, Jan, et al.
(författare)
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A rat model for orthodontic translational expansive tooth movement
- 2013
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Ingår i: Orthodontics & craniofacial research. - : John Wiley & Sons. - 1601-6335 .- 1601-6343. ; 16:4, s. 223-233
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To present the development of an experimental model in rats for translational expansive tooth movement. SETTING AND SAMPLE: Section of Periodontology at Department of Dentistry Aarhus University. Twenty male Wistar rats in two pilot experimental settings plus seven animals without any intervention serving as controls. MATERIAL AND METHODS: The second molar (group P1) or the second and third molar (group P2) in the maxillae of the animals were moved buccally using transpalatal β-titanium springs. In the group P2, two spring types (high force and low force) and two preangulations (0° passive or 30° torsion moment) were tested. The amount and type of tooth movement achieved and the resulting skeletal effect were assessed on microCT images, histological analysis was performed on few selected specimens. RESULTS: Expansive translational root movement amounting half a tooth width was achieved. Comparison of the amount of tooth movement at the right and left side of the maxilla showed that the expansion was rather symmetrical in the P2 group. Skeletal widening of the maxilla contributed in the P2 group to approximately one-third of the total root movement, whereas two-thirds were dental movement. CONCLUSION: With the model used in the P2 group, further research on translational expansive tooth movement and its effect on the periodontium can be pursued. In models for orthodontic expansion, it is strongly recommended to separately evaluate skeletal and dental effects.
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2. |
- Danz, Jan, et al.
(författare)
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Virtual tissue alignment and cutting plane definition : a new method to obtain optimal longitudinal histological sections
- 2014
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Ingår i: Journal of Anatomy. - : John Wiley & Sons. - 0021-8782 .- 1469-7580. ; 224:2, s. 85-94
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Tidskriftsartikel (refereegranskat)abstract
- Histomorphometric evaluation of the buccal aspects of periodontal tissues in rodents requires reproducible alignment of maxillae and highly precise sections containing central sections of buccal roots; this is a cumbersome and technically sensitive process due to the small specimen size. The aim of the present report is to describe and analyze a method to transfer virtual sections of micro-computer tomographic (CT)-generated image stacks to the microtome for undecalcified histological processing and to describe the anatomy of the periodontium in rat molars. A total of 84 undecalcified sections of all buccal roots of seven untreated rats was analyzed. The accuracy of section coordinate transfer from virtual micro-CT slice to the histological slice, right-left side differences and the measurement error for linear and angular measurements on micro-CT and on histological micrographs were calculated using the Bland-Altman method, interclass correlation coefficient and the method of moments estimator. Also, manual alignment of the micro-CT-scanned rat maxilla was compared with multiplanar computer-reconstructed alignment. The supra alveolar rat anatomy is rather similar to human anatomy, whereas the alveolar bone is of compact type and the keratinized gingival epithelium bends apical to join the junctional epithelium. The high methodological standardization presented herein ensures retrieval of histological slices with excellent display of anatomical microstructures, in a reproducible manner, minimizes random errors, and thereby may contribute to the reduction of number of animals needed.
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3. |
- Hämmerle, Christoph H F, et al.
(författare)
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Biology of soft tissue wound healing and regeneration : consensus report of group 1 of the 10th European workshop on periodontology
- 2014
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Ingår i: Journal of Clinical Periodontology. - : John Wiley & Sons. - 0303-6979 .- 1600-051X. ; 41:s15, s. S1-S5
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- BACKGROUND:The scope of this consensus was to review the biological processes of soft tissue wound healing in the oral cavity and to histologically evaluate soft tissue healing in clinical and pre-clinical models. AIMS:To review the current knowledge regarding the biological processes of soft tissue wound healing at teeth, implants and on the edentulous ridge. Furthermore, to review soft tissue wound healing at these sites, when using barrier membranes, growth and differentiation factors and soft tissue substitutes. COLLECTION OF DATA:Searches of the literature with respect to recessions at teeth and soft tissue deficiencies at implants, augmentation of the area of keratinized tissue and soft tissue volume were conducted. The available evidence was collected, categorized and summarized. FUNDAMENTAL PRINCIPLES OF ORAL SOFT TISSUE WOUND HEALING:Oral mucosal and skin wound healing follow a similar pattern of the four phases of haemostasis, inflammation, proliferation and maturation/matrix remodelling. The soft connective tissue determines the characteristics of the overlaying oral epithelium. Within 7-14 days, epithelial healing of surgical wounds at teeth is completed. Soft tissue healing following surgery at implants requires 6-8 weeks for maturation. The resulting tissue resembles scar tissue. Well-designed pre-clinical studies providing histological data have been reported describing soft tissue wound healing, when using barrier membranes, growth and differentiation factors and soft tissue substitutes. Few controlled clinical studies with low numbers of patients are available for some of the treatments reviewed at teeth. Whereas, histological new attachment has been demonstrated in pre-clinical studies resulting from some of the treatments reviewed, human histological data commonly report a lack of new attachment but rather long junctional epithelial attachment and connective tissue adhesion. Regarding soft tissue healing at implants human data are very scarce. CONCLUSIONS:Oral soft tissue healing at teeth, implants and the edentulous ridge follows the same phases as skin wound healing. Histological studies in humans have not reported new attachment formation at teeth for the indications studied. Human histological data of soft tissue wound healing at implants are limited. CLINICAL RECOMMENDATIONS:The use of barriers membranes, growth and differentiation factors and soft tissue substitutes for the treatment of localized gingival/mucosal recessions, insufficient amount of keratinized tissue and insufficient soft tissue volume is at a developing stage.
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4. |
- Lang, Niklaus, et al.
(författare)
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Osseointegration
- 2021
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Ingår i: Lindhe's Clinical Periodontology and Implant Dentistry, 2 Volume Set, 7th Edition. - Oxford, UK : Wiley-Blackwell. - 9781119438885
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Bokkapitel (refereegranskat)
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5. |
- Miron, Richard J., et al.
(författare)
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Twenty years of enamel matrix derivative : the past, the present and the future
- 2016
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Ingår i: Journal of Clinical Periodontology. - : Blackwell Munksgaard. - 0303-6979 .- 1600-051X. ; 43:8, s. 668-683
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Forskningsöversikt (refereegranskat)abstract
- Background On June 5th, 2015 at Europerio 8, a group of leading experts were gathered to discuss what has now been 20years of documented evidence supporting the clinical use of enamel matrix derivative (EMD). Original experiments led by Lars Hammarstrom demonstrated that enamel matrix proteins could serve as key regenerative proteins capable of promoting periodontal regeneration including new cementum, with functionally oriented inserting new periodontal ligament fibres, and new alveolar bone formation. This pioneering work and vision by Lars Hammarstrom has paved the way to an enormous amount of publications related to its biological basis and clinical use. Twenty years later, it is clear that all these studies have greatly contributed to our understanding of how biologics can act as mediators for periodontal regeneration and have provided additional clinical means to support tissue regeneration of the periodontium. Aims This review article aims to: (1) provide the biological background necessary to understand the rational for the use of EMD for periodontal regeneration, (2) present animal and human histological evidence of periodontal regeneration following EMD application, (3) provide clinically relevant indications for the use of EMD and (4) discuss future avenues of research including key early findings leading to the development of Osteogain, a new carrier system for EMD specifically developed with better protein adsorption to bone grafting materials
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6. |
- Polyzois, Ioannis, et al.
(författare)
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Effect of Bio-Oss (R) on osseointegration of dental implants surrounded by circumferential bone defects of different dimensions : an experimental study in the dog
- 2007
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Ingår i: Clinical Oral Implants Research. - 0905-7161 .- 1600-0501. - 0905-7161 ; 18:3, s. 304-310
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: This study was designed to evaluate the effect of gap width and graft placement on bone healing around implants placed in simulated extraction sockets of various widths in four Labrador dogs. Materials and Methods: Five Osseotite (R) implants per dog were placed in the mandible of four dogs. Two implants were inserted into sites with a 2.37 mm and two with a 1 mm gap present between the implants and bone around the coronal 6 mm of the implants in each dog. For one of each gap sizes, the gap was filled with Bio-Oss (R), and the other two with blood alone. A fifth implant was inserted without a gap and used as a control. Ground sections were prepared from biopsies taken at 4 months and histometric measurements of osseointegration and bone between the threads made for the coronal 6 mm. Results: The medians for osseointegration ranged from 5.2 mm for control to 1-2.6 mm for the test modalities. There were significant differences for linear measurements of osseointegration ((2)(chi) 18.27; df 4; P = 0.0011) and bone area within threads (chi(2) 23.4; df 4; P = 0.0001) between test modalities. Conclusions: The results suggest that the wider the gap around the implants, the less favourable the histological outcome at short time intervals following treatment. They also infer that bone grafting with anorganic bovine bone xenograft seems to lead to a more favourable histological outcome for wider circumferential defects but not for narrower defects.
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7. |
- Polyzois, Ioannis, et al.
(författare)
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Effect of Bio-Oss (R) on osseointegration of dental implants surrounded by circumferential bone defects of different dimensions : an experimental study in the dog
- 2007
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Ingår i: Clinical Oral Implants Research. - : Blackwell Munksgaard. - 0905-7161 .- 1600-0501. ; 18:3, s. 304-310
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: This study was designed to evaluate the effect of gap width and graft placement on bone healing around implants placed in simulated extraction sockets of various widths in four Labrador dogs. Materials and Methods: Five Osseotite (R) implants per dog were placed in the mandible of four dogs. Two implants were inserted into sites with a 2.37 mm and two with a 1 mm gap present between the implants and bone around the coronal 6 mm of the implants in each dog. For one of each gap sizes, the gap was filled with Bio-Oss (R), and the other two with blood alone. A fifth implant was inserted without a gap and used as a control. Ground sections were prepared from biopsies taken at 4 months and histometric measurements of osseointegration and bone between the threads made for the coronal 6 mm. Results: The medians for osseointegration ranged from 5.2 mm for control to 1-2.6 mm for the test modalities. There were significant differences for linear measurements of osseointegration ((2)(chi) 18.27; df 4; P = 0.0011) and bone area within threads (chi(2) 23.4; df 4; P = 0.0001) between test modalities. Conclusions: The results suggest that the wider the gap around the implants, the less favourable the histological outcome at short time intervals following treatment. They also infer that bone grafting with anorganic bovine bone xenograft seems to lead to a more favourable histological outcome for wider circumferential defects but not for narrower defects.
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8. |
- Sculean, Anton, et al.
(författare)
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Self-regenerative capacity of intra-oral bone defects
- 2019
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Ingår i: Journal of Clinical Periodontology. - : John Wiley & Sons. - 0303-6979 .- 1600-051X. ; 46:S21, s. 70-81
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Tidskriftsartikel (refereegranskat)abstract
- Objective To provide an overview on the self-regenerative capacity of various types of intra-oral bone defects. Materials and Methods This paper has narratively reviewed the most important aspects of bone biology and the healing outcomes related to the self-regenerative capacity (i.e. without the placement of any biomaterial) of bone defects that occur following tooth extraction, autogenous graft harvesting, periapical lesions, cystic lesions of the jaws, third molar extraction and experimentally created ridge defects. Results In animals (i.e. dogs and monkeys), the greatest changes in horizontal and vertical dimension occur during the first 6 months following tooth extraction. In humans, bone remodelling may take from several months to years and exhibits marked inter-individual variability. Following tooth extraction at compromised sites (e.g. presence of severe bone loss at the time-point of extraction), the healing may occur slower and a substantial volume reduction can be expected than following tooth extraction at non-compromised sites. In the mandibular symphysis and ramus, the bone defects resulting following bone block harvesting are gradually healing to a large extent, but complete healing appears not to occur due to poorer space provision and wound stability capacities. Defects after peri-apical surgery display a substantial self-regenerative capacity and heal at a great extent without the use of any adjunct measures. The vast majority of jawbone defects after cystectomy heal at a great extent and without apparent influence in the shape of the jaw, without the need of adjunct measures. After surgical removal of mandibular third molars, bone fill can be observed over a period of at least 12 months, with the most substantial change (e.g. the greatest bone fill) occurring during the first 3 months after surgery. However, complete fill of these residual bone defects does not always occur. Conclusions Intra-oral bone defects possess a high self-regenerative capacity. Factors such as extent of bone loss, presence of bony walls, closed healing environment, space provision and mechanical wound stability substantially influence healing/regeneration.
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9. |
- Stavropoulos, Andreas, et al.
(författare)
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Pre-clinical in vivo models for the screening of bone biomaterials for oral/craniofacial indications : focus on small-animal models
- 2015
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Ingår i: Periodontology 2000. - : John Wiley & Sons. - 0906-6713 .- 1600-0757. ; 68:1, s. 55-65
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Tidskriftsartikel (refereegranskat)abstract
- Preclinical in vivo experimental studies are performed for evaluating proof-of-principle concepts, safety and possible unwanted reactions of candidate bone biomaterials before proceeding to clinical testing. Specifically, models involving small animals have been developed for screening bone biomaterials for their potential to enhance bone formation. No single model can completely recreate the anatomic, physiologic, biomechanic and functional environment of the human mouth and jaws. Relevant aspects regarding physiology, anatomy, dimensions and handling are discussed in this paper to elucidate the advantages and disadvantages of small-animal models. Model selection should be based not on the 'expertise' or capacities of the team, but rather on a scientifically solid rationale, and the animal model selected should reflect the question for which an answer is sought. The rationale for using heterotopic or orthotopic testing sites, and intraosseous, periosseous or extraskeletal defect models, is discussed. The paper also discusses the relevance of critical size defect modeling, with focus on calvarial defects in rodents. In addition, the rabbit sinus model and the capsule model in the rat mandible are presented and discussed in detail. All animal experiments should be designed with care and include sample-size and study-power calculations, thus allowing generation of meaningful data. Moreover, animal experiments are subject to ethical approval by the relevant authority. All procedures and the postoperative handling and care, including postoperative analgesics, should follow best practice.
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10. |
- Stähli, Alexandra, et al.
(författare)
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The effect of connective tissue graft or a collagen matrix on epithelial differentiation around teeth and implants : a preclinical study in minipigs
- 2023
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Ingår i: Clinical Oral Investigations. - : Springer. - 1432-6981 .- 1436-3771. ; 27:8, s. 4553-4566
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: This study aimed to histologically evaluate the healing at 8 weeks after coronally advanced flap (CAF) with either a superficial (SCTG) or deep palatal connective tissue graft (DCTG), or a collagen matrix (CM) to cover recession defects at teeth and implants.MATERIAL AND METHODS: One mandibular side of 6 miniature pigs received each 3 titanium implants 12 weeks after extraction. Eight weeks later, recession defects were created around implants and contralateral premolars and 4 weeks later randomly subjected to CAF + SCTG, CAF + DCTG, or CAF + CM. After 8 weeks, block biopsies were histologically analyzed.RESULTS: For the primary outcome, i.e., keratinization of the epithelium, all teeth and implants exhibited a keratinized epithelium with no histological differences among them also not in terms of statistically significant differences in length (SCTG 0.86 ± 0.92 mm, DCTG 1.13 ± 0.62 mm, and Cm, 1.44 ± 0.76 mm). Pocket formation was histologically seen at all teeth, around most implants with SCTG and DCTG, however not in the CM implant group. The connective tissue grafts showed hardly signs of degradation, whereas the CM was partly degraded and integrated in connective tissue. The mean gain in gingival height was similar in all experimental groups (SCTG 3.89 ± 0.80 mm, DCTG 4.01 ± 1.40 mm, CM 4.21 ± 0.64 mm). Statistically significant differences were found in the height of the junctional epithelium between the control teeth and the connective tissue groups (p = 0.009 and 0.044).CONCLUSIONS: In this animal model, the use of either a superficial or deep connective tissue graft or a collagen membrane did not seem to have any impact on the epithelial keratinization around both teeth and implants. All procedures (CAF + SCTG/DCTG/CM) resulted in a long JE that was even longer at implants.CLINICAL RELEVANCE: Deep/superficial palatal connective tissue graft yielded similar keratinization around teeth/implants. Given the absence of pocket formation and inflammatory processes at implants when using a CM, CAF + CM might bear potential clinical benefits.
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