Programming and support:  SSMU IC

International Scientific activities of University

IADR/AADR/CADR General Session & Exhibition, San Francisco, Calif., USA — March 22−25, 2017

The International Association for Dental Research (IADR), is a nonprofit organization with nearly 11,000 members worldwide.

Its mission is:

— to advance research and increase knowledge for the improvement of oral health worldwide;

— to support and represent the oral health research community;

— to facilitate the communication and application of research findings.

The 95th General Session & Exhibition of the IADR, was held in conjunction with the 46th Annual Meeting of the AADR and the 41st Annual Meeting of the CADR at the Moscone West, 800 Howard St at the corner of Fourth & Howard streets, San Francisco, CA 94103.

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More than 6,500 delegates from 72 countries attended the 95th General Session & Exhibition of the IADR. Each year, the International Association for Dental Research (IADR) strives to advance research and increase knowledge for the improvement of oral health worldwide. This year was no exception. Those attending the meeting could choose from among 1,326 posters, 467 oral presentations, 23 Lunch & Learning topics, 41 symposia, four hands-on workshops, six meet-a-mentor topics, two satellite symposia and three plenary sessions. Delegates also had the opportunity to visit the exhibit hall, which housed 39 total exhibition booths: 28 corporate and 11 were institutional/government/nonprofits.

This meeting attended a group of leading researchers of our University with active contributions:

Prof. Dr. Grimm:

Bone Formation, Bone remodeling, Bone Augmentation and Sinus Lift

Oral Session: Implantology Research

Prof. Grimm chaired this session together with Prof. Dr. S. Park (Advanced Prosthodontics, UCLA, School of Dentistry, Los Angeles, California, USA)

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Figures: Prof. Grimm was chairing the Oral Session / Implantology Research «Bone Formation, Bone remodeling, Bone Augmentation and Sinus Lift» together with Prof. Park from the UCLA, USA

Figures: Prof. Grimm was given an active talk to this session presenting the results of our international research group

Osteoporotic Sheep Mandibular Model for Comparative Dental Implant Research

W. Grimm1;2 N. Didenko2; W. J. Duncan3; T. Fritsch4; B. Giesenhagen5; S. Hakki6; E. Shchetinin7; A. Sletov8; O. Vladimirova2; M. Vukovic1; S. Sirak8
1Periodontology, University of Witten, Witten, Germany; 2Regenerative Medicine, Stavropol State Medical University, Stavropol, Russian Federation; 3School of Dentistry, University of Otago, Dunedin, New Zealand; 4Medicine, Gesundheitscampus Luzern, Luzern, Switzerland; 5Oral Surgery, University of Frankfurt /M, Frankfurt/M, Germany; 6Periodontology, Selcuk University, Konya, Turkey; 7Pathophysiology, Stavropol State Medical University, Stavropol, Russian Federation; 8Oral surgery, Stavropol State Medical University, Stavropol, Russian Federation

Objectives: Reproducible and suitable animal models are required for in vivo experiments. The aim of the present study was to investigate the suitability of the mandibular ridge in osteoporotic sheep (OS) for comparative dental implant research, to establish histological protocols for this model, to study the effect of variations in healing of tooth extraction sockets and of critical-size bone defects.

Methods: Six young female sheep (Stavropol breed) with an average body weight of 30 kg have been used. Surgical procedures has been conducted according the local ethical committee at the StSMU (number 39, April 16, 2014). Six months prior to the study, sheep had been neutered by ovariectomy to induce osteoporosis. Bone density (BD) was measured using 3D radiographic images.
The study was performed in two surgical phases, extraction of premolars, and creation of standardized box-shaped defects (12mm critical-size defect, CSD), bilaterally (Duncan, 2005). After 12 weeks, block sections were obtained from the experimental sites. Qualitative histological analysis on decalcified and on non-decalcified sections using Technovit 9100 New as a PMMA-based embedding technique (Witte et al. 2010) with different stains was carried out.

Results: The Hounsfield units found clearly support the hypothesis of OS model. BMD showed significant microstructural evolutions on the bone compartment. Histological examination over 12 weeks showed variations in healing responses. Investigated standardized areas of newly formed bone were characterized by a low-intense staining of the mineralized matrix. TB staining indicated that new trabeculae of woven bone mainly arized from open bone marrow spaces of the adjacent alveolar bone. In all animals, the peripheral part of the spongiosa appeared to be lower mineralized than in the centre. Lack of osteoclasts has been illustrated by Tartrate-resistant acidic phosphatase (TRAP).

Conclusions: This experimental animal model provides an excellent basis for testing newly developed implants for their suitability. In the next future, we will be able to use this model for investigating the effect of stem cell supported treatments (Grimm et al. 2015) in regeneration of segmental mandibular bone defects in osteoporotic sheep transplanting ovine NCSCs from palate (Widera et al. 2009).

Keywords Osteoporotic sheep, animal models, tooth extraction site model, 12 mm critical size defect, qualitative histology

Osseointegration of Newly Developed Ceramic Implants in Osteoporotic Sheep

Session Systemic Diagnosis, Systemic Effects, RNA Extraction

Figure: Prof. Grimm in front of the joint poster of our research group, in conversation with Prof. Spar (University of Sydney, Australia) and Prof. Romanov (University of Stony Brooks, New York, USA)

T. Fritsch1; M. Aybazov2; N. Didenko3; B. Giesenhagen4; S. Sirak5; A. Sletov6; S. Tebyakina3; W. Grimm7,3
1Medicine, Gesundheitscampus Luzern, Luzern, Switzerland; 2Sheep breeding, All Russia Research Institute for Goat and Sheep, Stavropol, Russian Federation; 3Regenerative Medicine, Stavropol State Medical University, Stavropol, Russian Federation; 4Oral Surgery, University of Frankfurt/M, Frankfurt /M, Germany; 5Stomatology, Stavropol State Medical University, Stavropol, Russian Federation; 6Oral Surgery, Stavropol State Medical University, Stavropol, Russian Federation; 7Periodontology, University of Witten, Witten, Germany

Objectives: It is a clinical challenge to obtain a sufficient dental implant fixation in osteoporotic bone. The hypothesis tested was the post-extraction osteoporotic sheep mandible is a suitable model for comparative dental implantology research.

Methods: Ceramic implants are new prototype dental implants. Titanium implants as clinically approved dental implants have been used as controls.
SEM were obtained from ceramic and titanium implants for observation of the surface morphology. The chemical composition of the surface coating was analyzed with EDX.
Six young female sheep (Stavropol breed) with an average body weight of 30 kg have been used. One animal served as control for exploring the osteoporotic microstructural evolutions on the bone compartment by measuring the Bone density (BMD).
Implants (Titanium control and Ceramic test) have been placed into mandibular postextraction ridges for comparing the osseointegration (Duncan et al., 2015).
After 12 weeks, block sections were obtained from all of implant sites. Qualitative histological analysis on non-decalcified sections using Technovit 9100 New as a PMMA-based embedding technique (Witte et al. 2010) with different stains was carried out.

Results: SEM of the surfaces demonstrated the roughening on titanium implants and showed the modulation of ceramic surfaces. The results of EDX Analysis between both of implant groups will be demonstrated.
Long-term corticosteroid and total ovariectomy resulted in a osteoporotic bone deficit in the control animal not adversely affecting the general health of the sheep.
Histological analysis of osseointegration observed in both of implant groups demonstrated obvious differences with respect to the pattern of implant/bone regeneration. All implants showed signs of osteoconduction and integration after 12 weeks healing with no evidence of inflammation around titanium implants. Ceramic specimens had large masses of disorganized calcified material which appeared to be resorbed bone tissue. Lack of osteoclasts has been illustrated by Tartrate-resistant acidic phosphatase (TRAP) in the ceramic group.

Conclusions: In summary, bone tissue early integration was significantly stronger for the titanium implants compared with ceramic implants in our extraction site model using osteoporotic sheep 12 weeks after implant insertions.

Keywords Osteoporotic Sheep, Scanning Electron Microscopy and EDX Analysis, Animal study, Histological analysis, ceramic and titanium implants

Prof. Dr Sirak/ Prof. Dr. Sletov:

Osteogenic Potential of Porous Titanium: An Experimental Study in Sheep

Session Biological Effects/Implants[WG1]

S. Sirak1; M. Aybazov2; T. Kobylkina1; E. Shchetinin3; A. Sletov4; W. Grimm5,1
1Stomatology, Stavropol State Medical University, Stavropol, Russian Federation; 2Sheep breeding, All Russia Research Institute for Goat and Sheep, Stavropol, Russian Federation; 3Pathophysiology, Stavropol State Medical University, Stavropol, Russian Federation; 4Oral Surgery, Stavropol State Medical University, Stavropol, Russian Federation; 5Periodontology, University of Witten, Witten, Germany

Objectives: Due to its excellent biocompatibility and favorable osteogenic properties, highly porous TiO2 granules has been proposed as a promising material for non-resorbable synthetic bone grafts in the restoration of large bone defects, and for bone augmentation in dental applications. The aim of this study was to investigate the osteoconductive properties and biological performance of porous titanium granules used in osseous defects adjacent to the maxillary sinus in sheep.
Methods: The present study was approved by the Ethics Committee of the StSMU (98/4, 10/03/2011) and was performed on 12 sheep (Stavropol breed) in accordance to sheep sinus augmentation models described by Sauerbier et al., 2010; Seoane et al., 2012; and Barbone et al., 2013. Calibrated defects were prepared in the subantral region of sheep and were randomized into test and control group. The test defects were grafted with porous titanium granules (PTG), whereas control defects were left empty (sham). Defects were left for healing for 30, 60, and 90 days. After healing, the grafted areas were removed and finally osteoconductivity was analyzed by using x-ray (OPG) and by qualitative histology on decalcified sections with different stains.
Results: At three time periods post-transplantation, the regenerated bone height were 3.3 ± 0.6 mm in the PTG-grafted group, and 0.3 ± 0.5 mm in the untreated control group. Histopathological photomicrographs showed at 30 days that the titanium granules got overgrown and integrated in connective tissue fibers. On day 90 the titanium-bone interconnection adhered closely to the defect walls with no interface in between. After 3 months the bone trabeculae got some well-ordered structure, the collagen fibers got arranged in parallel rows and forming thin trabecular arcs anastomosing very closely. Over the time schedule of the study significantly more new bone formed in PTG-grafted defects compared with sham. The control group showed significantly less expression of key inflammation cells, but with no significant difference in key inflammation cells compared with the experimental groups.
Conclusions: Porous titanium can offer as an effective alternative to calcium phosphate and bone collagen based materials used for subantral augmentation of the maxillary bone in cases of dental implantation.

Keywords porous titanium granules, subantral augmentation, standardized sheep model, x-ray, qualitative histology on decalcified sections

These active contributions to the meeting of the the 95th General Session & Exhibition of the IADR will be published in a special issue of Journal of Dental Research (JDR) 2017, Vol. 96, Special Issue A.

This year, according to the Journal Citation Reports®; (Thomson Reuters, 2016), JDR holds its highest 2-Year Impact Factor in the «Dentistry, Oral Surgery & Medicine» category at 4.602 and ranks #2 of 89 journals in that same category. At 1.530, the Journal also ranks #1 in Article Influence. JDR citation ranking (CTR) is dedicated to publishing original research at the interface between discovery science and clinical application, with the translation of research into healthcare delivery systems at the individual patient, clinical practice, and community levels.

Attending the meeting of the PERIODONTAL RESEARCH GROUP (PRG)

Prof. Grimm attended the meeting of the PERIODONTAL RESEARCH GROUP (PRG) at San Francisco Meeting of the International Association for Dental Research (IADR).

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The Periodontal Research Group (PRG) is a forum for IADR’s active members (Prof. Grimm is a member of this group since 1992) involved in any aspect of periodontal research.

PRG’s overarching mission is to advance periodontal research activities and increase knowledge with the aim to improve periodontal health on the patient and population level.

In addition to the objectives of the IADR, PRG also aims to facilitate presentation, discussion, and publication of scientific papers on periodontal research, and to identify and support excellence in both young and established scientists in Periodontology through its competitive awards and grants. The world-wide PRG membership is 1175 active research member over all of continents.

For this reason, Prof. Grimm is a member of the reviewer group of the J of Periodontal Research (Edited By: Dr. Shinya Murakami, Impact Factor: 2.474, ISI Journal Citation Reports © Ranking: 2015: 16/91 (Dentistry Oral Surgery & Medicine), Online ISSN: 1600−0765), the leading publication of the IADR PERIODONTAL RESEARCH GROUP (PRG).

Meeting with group members Prof. Grimm could have included as members of the Editorial Board of our Journal «Medical News of North Caucasus»:

— Prof. Dr. A. Kantarci (Boston University Henry M. Goldman School of Dental Medicine, past president of the PRG)

— Prof. Dr. H. Jentzsch (University of Leipzig, Germany)

— Prof. Dr. S. S. Hakki (University of Konya, Turkey)

— Prof. Dr. A. Spar (University of Sydney, Australia)

— Prof. Dr. Romanov (University of Stony Brooks, New York, USA).


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