Bone Tissue Level Research Articles

Zinc Supplementation Increased Bone Mineral Density, Improves Bone Histomorphology, and Prevents Bone Loss in Diabetic Rat.

Diabetic osteoporosis (DOP) is a complication of diabetes, with the characteristics of bone mineral density (BMD) reduction and bone structure destruction. Zinc was reported has a benefit effect on postmenopausal osteoporosise, it was also has hypoglycemic effect, whether zinc was beneficial on diabetes-induced osteoporosis has not been reported. So in the present study, we established a diabetic rat model by streptozotocin injection (60mg/kg), and administered zinc sulfate by oral gavage to investigate the protective effects of zinc on DOP and the underline possible mechanism. Thirty six Sprague Dawley rats were divided into T1DM group (diabetic rats), control group (vehicle treatment), and T1DM-Zinc group (diabetic rats administered zinc sulfate 0.25mg/kg by oral gavage). The bone histomorphological parameters, serum bone metabolism markers (including ALP, OPG, RUNX 2, and RANKL), BMD, and bone marrow adipocyte numbers were detected after eight weeks of zinc sulfate treatment. The results showed zinc sulfate administration (0.25mg/kg/d) decreased blood glucose, increased the BMD, decreased serum ALP, and RANKL, increased serum OPG and RUNX 2 levels, as well as OPG/RANKL ratio of T1DM rats. Meanwhile, the bone histomorphological parameters, bone marrow adipocytes numbers were returned to be normal. The RUNX 2, and OPG mRNA expression levels in bone tissues of T1DM-Zinc group rats were increased after zinc sulfate treatment compared with the diabetic rats (P < 0.05). Those indicating that zinc sulfate can prevent DOP, the protective mechanism were mainly related to its hypoglycemic effect, bone marrow lipogenesis inhibition effect, OPG/RANKL ratio and RUNX 2 up-regulation effect.

Level of Osteotropic Elements in the Jaw Bones of Experimental Animals in Terms of the Impact of Xenobiotics

Pollution of the environment with heavy metals, pesticides, nitrates leads to an unceasing deterioration of the population’s health, in particular, the dental one. Excessive intake of salts of heavy metals and nitrites is accompanied by changes in calcium-phosphorus metabolism rates, indicating a disorder of metabolic processes in bone tissue. This necessitates the study of the level of osteotropic elements of the jaw bone tissue.&#x0D; Materials and methods of research. In the experiment on 80 white outbred male rats, the effects of cadmium chloride, sodium nitrite and their combined action on the content of osteotropic elements in the jaw bone were studied. The control group consisted of 10 intact animals.&#x0D; Results. It was determined that in the dynamics (1st, 14th, 28th days) of both cadmium-nitrite, nitrite and cadmium intoxication there was observed the accumulation of cadmium and decrease of calcium, copper, zinc levels in bone tissue of animal jaws compared to intact group.&#x0D; Conclusions.The most significant changes in the level of osteotropic elements in the jaw bones are found in the combined effect of xenobiotics, which is important for understanding of the metabolic processes in the oral cavity.

MicroRNA-29a-3p regulates osteoblast differentiation and peri-implant osseointegration in a rat model of hyperlipidemia by modulating Frizzled 4 expression

This work aimed to study and identify the influence and target gene of microRNA-29a-3p (miR-29a-3p) in the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) in a high-fat environment in vitro and in vivo. 1) In vitro: BMSCs were randomly allocated into two groups and were then induced to undergo osteogenic differentiation in a normal or high-fat environment. Next, a miR-29a-3p mimic/inhibitor was transfected into the two groups of cells. The mRNA expression levels of alkaline phosphatase (ALP), Runt related gene 2 (Runx2), and miR-29a-3p and the protein expression levels of ALP and Runx2 were detected before and after transfection through reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) and Western blot analyses. Moreover, Frizzled (Fzd) 4 was predicted as the target gene of miR-29a-3p by using an online database (Target Scan, MiRNA.org). The interactive relationship between miR-29a-3p and Fzd4 was confirmed through dual-luciferase assays. 2) In vivo: Rats were randomly divided into two groups and fed with a standard or high-fat diet. Titanium implants were grown in rats. Then, the expression levels of miR-29a-3p, ALP, and Runx2 were detected in bone tissues surrounding implants. Moreover, hard tissue sections were subjected to methylene blue-acid magenta staining and observed under microscopy to study bone formation around implants. In addition, miR-29a-3p-overexpressing lentiviral vectors were transfected into rats, and the expression levels of ALP, Runx2, and miR-29a-3p in bone tissues surrounding implants were detected at 3 and 10 days after transfection. The expression levels of ALP, Runx2, and miR-29a-3p and the osteogenic differentiation of BMSCs were suppressed in high-fat groups in vitro and in vivo. MiR-29a-3p plays a positive role in the regulation of BMSCs in a high-fat environment. It can increase ALP and Runx2 expression levels in bone tissues surrounding implants in hyperlipidemia models. This result implies that miR-29a-3p can promote implant osseointergration in a rat model of hyperlipidemia.

Regulatory effect of miR-421 on humeral fracture and heterotopic ossification in elderly patients.

The present study aimed to investigate the role of miR-421 and bone morphogenetic protein-2 (BMP-2) in the bone tissues and blood of elderly patients with humeral fractures and heterotopic ossification. A total of 38 patients with humeral fractures, including 16 patients who received surgery within 1-7 days of fracture and 22 patients who received surgery within 8-14 days of fracture, were enrolled. An additional 18 patients who had heterotopic ossification and 26 patients who had humeral fracture and not heterotopic ossification were also included. Bone tissues and blood were collected. Reverse transcription-quantitative polymerase chain reaction was performed to determine the miR-421 and BMP-2 mRNA expression levels in the samples. Western blotting and ELISA were performed to detect BMP-2 protein levels in bone tissues and blood, respectively. Dual-luciferase reporter assays were performed to verify whether BMP-2 is the direct target gene of miR-421. Compared with the patients who received surgery 1-7 days after fracture, the patients who accepted the surgery 8-14 days after fracture had significantly increased levels of BMP-2 mRNA and protein in their bone tissues and blood (P<0.05). Contrastingly, the expression level of miR-421 decreased in the samples from patients who accepted the surgery 8-14 days after fracture compared with the level in those who received surgery 1-7 days after fracture (P<0.05). Compared with the patients without heterotopic ossification, the patients with heterotopic ossification had increased BMP-2 mRNA and protein expression levels in their bone tissues and blood, whereas the expression of miR-421 was significantly decreased (P<0.05). The dual-luciferase reporter assay demonstrated that BMP-2 was the direct target gene of miR-421. The upregulation of BMP-2 may be associated with the downregulation of miR-421. miR-421 may regulate the recovery of humeral fracture and heterotopic ossification through BMP-2. The results of the present study may provide a theoretical basis for the diagnosis and treatment of humeral fracture and heterotopic ossification.

Stress and Strain Distribution Patterns in Bone around Tissue- and Bone-Level Implant-Supported Mandibular Overdentures Using Three-Dimensional Finite-Element Analysis.

Our aim is to investigate the effect of implant placement in two positions (bone level and tissue level) on stress and strain distribution around mandibular implant overdentures. We use two models of mandibular overdentures. Taper implants are inserted and collimated between the lateral and canine teeth. All structures are scanned, digitized, and three-dimensioned (3D) model designed. We apply a vertical load of 100 N simultaneously on the central fossa of the mandibular first molar of the two models (bone- and tissue-level implant). Stress and strain values are obtained using 3D finite-element analysis (FEA). In comparison to the tissue-level model, bone-level implants can reduce overdenture movement and tension by 0.8 μm. The results of this study show that using bone-level implants can reduce tension on the prosthesis part of the overdenture and the bone around the implants as well as on the movement of the distal end of the mandibular overdenture. We found that bone strain occurred around implants within physiological limits in model 1 (bone level) compared to model 2 (tissue level). This shows that the distribution of physical forces in bone-level implants generally produces better results than those of issue-level implants. However, more research on the subject is needed.

The androgen receptor is required for maintenance of bone mass in adult male mice

Previous studies evaluating the role of the androgen receptor (AR) for bone mass have used mouse models with global or tissue-specific lifelong inactivation of the AR. However, these mouse models have the AR inactivated already early in life and the relative roles of the AR during development, sexual maturation and in adult mice cannot be evaluated separately. The aim of the present study was to determine the specific roles of the AR in bone during sexual maturation and in adult mice. The AR was conditionally ablated at four (pre-pubertal) or ten (post-pubertal) weeks of age in male mice using tamoxifen-inducible Cre-mediated recombination. Both the pre-pubertal and the post-pubertal AR inactivation were efficient demonstrated by substantially lower AR mRNA levels in seminal vesicle, bone and white adipose tissue as well as markedly reduced weights of reproductive tissues when comparing inducible ARKO mice and control mice at 14 weeks of age. Total body BMD, as analyzed by DXA, as well as tibia diaphyseal cortical bone thickness and proximal metaphyseal trabecular bone volume fraction, as analyzed by μCT, were significantly reduced by both pre-pubertal and post-pubertal AR inactivation. These bone effects were associated with an increased bone turnover, indicating a high bone turnover osteoporosis. Pre-pubertal but not post-pubertal AR inactivation resulted in substantially increased fat mass. In conclusion, the AR is required for maintenance of both trabecular and cortical bone in adult male mice while AR expression during puberty is crucial for normal fat mass homeostasis in adult male mice.

Mechanical behavior of metastatic vertebrae are influenced by tissue architecture, mineral content, and organic feature alterations.

Diminished vertebral mechanical behavior with metastatic involvement is typically attributed to modified architecture and trabecular bone content. Previous work has identified organic and mineral phase bone quality changes in the presence of metastases, yet limited work exists on the potential influence of such tissue level modifications on vertebral mechanical characteristics. This work seeks to determine correlations between features of bone (structural and tissue level) and mechanical behavior in metastatically involved vertebral bone. It is hypothesized that tissue level properties (mineral and organic) will improve these correlations beyond architectural properties and BMD alone. Twenty-four female athymic rats were inoculated with HeLa or Ace-1 cancer cells lines producing osteolytic (N = 8) or mixed (osteolytic/osteoblastic, N = 7) metastases, respectively. Twenty-one days post-inoculation L1-L3 pathologic vertebral motion segments were excised and μCT imaged. 3D morphometric parameters and axial rigidity of the L2 vertebrae were quantified. Sequential loading and μCT imaging measured progression of failure, stiffness and peak force. Relationships between mechanical testing (whole bone and tissue-level) and tissue-level material property modifications with metastatic involvement were evaluated utilizing linear regression models. Osteolytic involvement reduced vertebral trabecular bone volume, structure, CT-derived axial rigidity, stiffness and failure force compared to healthy controls (N = 9). Mixed metastases demonstrated similar trends. Previously assessed collagen cross-linking and proline-based residues were correlated to mechanical behavior and improved the predictive ability of the regression models. Similarly, collagen organization improved predictive regression models for metastatic bone hardness. This work highlights the importance of both bone content/architecture and organic tissue-level features in characterizing metastatic vertebral mechanics. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:3013-3022, 2018.

Rehabilitation of Postextractive Socket in the Premaxilla: A 12-Year Study on 27 Titanium Plasma Spray Resorbable Calcium Phosphate Coated Single Implants.

The purpose of this study was to evaluate the peri-implant bone tissue level on postextractive resorbable calcium phosphate coated single implants placed in premaxillary sites grafted with autologous bone, anorganic bovine bone (ABB), platelet-rich plasma (PRP), and keratinized epithelial connective graft over 12 years. A total of 27 patients received a postextractive single implant in premaxillary sites grafted with ABB and PRP. Two months later, a keratinized epithelial connective graft was applied and the implants loaded. Clinical and radiographical evaluations were performed at baseline, 6 and 18 months, 4 and 6 years after the implant insertion, and then every 2 years up to the 12th year. After 12 years, a total of 22 implants (81.48%), were available for the final data analysis; the implants achieved a 100% cumulative survival rate, and only a mild degree of periodontal tissue inflammation was recorded. The radiographic evaluation revealed a physiological marginal bone remodeling over the follow-up. Although a good preservation of the residual bone tissue in postextraction implant sites treated with keratinized epithelial connective tissue grafts was observed, the low number of treated cases does not allow us to propose this experimental protocol to all cases of bone defects but it certainly represents a new option. Further studies on a greater number of patients and using implants with different surface characteristics should be conducted for a better understanding of the indications of the proposed treatment.

PR674: Comparison of 5‐year outcomes of implant therapy using bone level or tissue level implants in a specialty practice

PR674: Comparison of 5‐year outcomes of implant therapy using bone level or tissue level implants in a specialty practice

Metabolic alterations in the bone tissues of aged osteoporotic mice

Age-related osteoporosis is characterized by reduced bone mineralization and reduced bone strength, which increases the risk of fractures. We examined metabolic changes associated with age-related bone loss by profiling lipids and polar metabolites in tibia and femur bone tissues from young (5 months old) and old (28 months old) male C57BL/6J mice using ultra-performance liquid chromatography quadrupole-time-of-flight mass spectrometry. Partial least-squares discriminant analysis showed clear differences in metabolite levels in bone tissues of young and old mice. We identified 93 lipid species, including free fatty acids, sphingolipids, phospholipids, and glycerolipids, that were significantly altered in bone tissues of old mice. In addition, the expression of 26 polar metabolites differed significantly in bone tissues of old mice and young mice. Specifically, uremic toxin metabolite levels (p-cresyl sulfate, hippuric acid, and indoxylsulfate) were higher in bone tissues of old mice than in young mice. The increase in p-cresyl sulfate, hippuric acid, and indoxylsulfate levels were determined using targeted analysis of plasma polar extracts to determine whether these metabolites could serve as potential osteoporosis biomarkers. This study demonstrates that LC-MS-based global profiling of lipid and polar metabolites can elucidate metabolic changes that occur during age-related bone loss and identify potential biomarkers of osteoporosis.

Implant Site Development Using Forced Eruption: A Mini Review

With the advent of esthetic dentistry, implant treatment has gained much importance, and osseointegrated implant requires appropriate positioning three-dimensionally to achieve optimum functional and esthetic results. The various techniques available for implant site development are mostly invasive with variable outcomes. On resorting to alternate modalities, orthodontic extrusion/forced eruption is the primary choice as it is noninvasive and aids in optimal increase in the volume of residual bone and soft tissue. In orthodontic extrusion, the available periodontal ligament acts as a source of cell supply and signals, while the socket itself acts as a naturally occurring scaffold for regeneration. The presence of gingival inflammation or active periodontal disease is always a negative predictor for periodontal regeneration. Hence, periodontal ligament in an uninflamed state is essential before performing orthodontic extrusion. This article aims to provide an insight into the mechanisms by which the periodontal ligament cells act at a molecular level to provide an improved bone and soft tissue levels for optimum implant placement.

Early arthritis induces disturbances at bone nanostructural level reflected in decreased tissue hardness in an animal model of arthritis

IntroductionArthritis induces joint erosions and skeletal bone fragility.ObjectivesThe main goal of this work was to analyze the early arthritis induced events at bone architecture and mechanical properties at tissue level.MethodsEighty-eight Wistar rats were randomly housed in experimental groups, as follows: adjuvant induced arthritis (AIA) (N = 47) and a control healthy group (N = 41). Rats were monitored during 22 days for the inflammatory score, ankle perimeter and body weight and sacrificed at different time points (11 and 22 days post disease induction). Bone samples were collected for histology, micro computed tomography (micro-CT), 3-point bending and nanoindentation. Blood samples were also collected for bone turnover markers and systemic cytokine quantification.ResultsAt bone tissue level, measured by nanoindentation, there was a reduction of hardness in the arthritic group, associated with an increase of the ratio of bone concentric to parallel lamellae and of the area of the osteocyte lacuna. In addition, increased bone turnover and changes in the microstructure and mechanical properties were observed in arthritic animals, since the early phase of arthritis, when compared with healthy controls.ConclusionWe have shown in an AIA rat model that arthritis induces very early changes at bone turnover, structural degradation and mechanical weakness. Bone tissue level is also affected since the early phase of arthritis, characterized by decreased tissue hardness associated with changes in bone lamella organization and osteocyte lacuna surface. These observations highlight the pertinence of immediate control of inflammation in the initial stages of arthritis.

Determination of a tissue-level failure evaluation standard for rat femoral cortical bone utilizing a hybrid computational-experimental method.

Macro-level failure in bone structure could be diagnosed by pain or physical examination. However, diagnosing tissue-level failure in a timely manner is challenging due to the difficulty in observing the interior mechanical environment of bone tissue. Because most fractures begin with tissue-level failure in bone tissue caused by continually applied loading, people attempt to monitor the tissue-level failure of bone and provide corresponding measures to prevent fracture. Many tissue-level mechanical parameters of bone could be predicted or measured; however, the value of the parameter may vary among different specimens belonging to a kind of bone structure even at the same age and anatomical site. These variations cause difficulty in representing tissue-level bone failure. Therefore, determining an appropriate tissue-level failure evaluation standard is necessary to represent tissue-level bone failure. In this study, the yield and failure processes of rat femoral cortical bones were primarily simulated through a hybrid computational-experimental method. Subsequently, the tissue-level strains and the ratio between tissue-level failure and yield strains in cortical bones were predicted. The results indicated that certain differences existed in tissue-level strains; however, slight variations in the ratio were observed among different cortical bones. Therefore, the ratio between tissue-level failure and yield strains for a kind of bone structure could be determined. This ratio may then be regarded as an appropriate tissue-level failure evaluation standard to represent the mechanical status of bone tissue.

The One Abutment-One Time Protocol: A Systematic Review and Meta-Analysis.

The use of definitive abutments (DAs) at time of implant placement has been introduced to overcome limitations of dis/reconnection of healing/provisional abutments (PAs). With little and inconsistent information in the literature regarding the effectiveness of using DAs, the aim of this systematic review is to examine marginal bone and soft tissue level changes, technical and biologic complications, and implant failure rate associated with use of DAs and PAs. This systematic review was prepared according to guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and online trial registers were searched for studies comparing use of DAs and PAs. The Cochrane Collaboration risk of bias tool was used to assess selected studies, and meta-analyses were performed using statistical software. A total of 1,124 citations were identified. Of these, seven trials with 363 dental implants in 262 participants were included in the analysis. Pooled estimates for marginal bone level changes showed significant differences between the two prosthetic techniques in favor of using DAs. No significant differences were found in soft tissue level changes, technical and biologic complications, or implant failure rate. Within the limitations of this review, DAs appear to be a viable alternative to PAs at time of implant placement. However, favorable changes in peri-implant marginal bone level associated with use of DAs should be viewed with caution as its clinical significance is still uncertain.

Effects of infraorbital nerve's anatomical course on the fracture pattern of the orbital floor

In this study, details of the infraorbital nerve's (ION's) anatomical course variants were compared using computed tomography (CT), and relationships between the variants and fracture patterns in the orbital floor were investigated. Fifty-two normal individuals and 50 patients with unilateral isolated orbital floor fractures were enrolled in this study. Four measurements in normal individuals and five measurements in fracture patients were obtained in parasagittal sections. The anatomical variations of the ION were categorized into three types according to the classification by Ferences etal. Among the normal individuals, 42 orbits were classified as type 1 ION, 48 orbits as type 2, and 14 orbits as type 3. The distance from the inferior orbital rim to the upper border of the inferior orbital foramen and the length of descension portion of the ION in type 1 ION were significantly shorter than in type 2 and type 3 IONs. In patients with orbital floor fractures, the distance from the inferior orbital rim to the upper border of the inferior orbital foramen was positively correlated with herniation level of bone and soft tissue. The ION had three anatomical variants according to the degree of descension in the anterior portion of the orbit. When fracture of the orbital floor occurs in patients with type 1 ION, inferior displacement of the fractured orbital bone and orbital soft tissue may be less severe than in patients with other ION types.

Independent Relationship between Serum Osteocalcin and Uric Acid in a Cohort of Apparently Healthy Obese Subjects.

It is generally accepted that serum osteocalcin (OC) is a reliable marker of bone formation, while the role of serum uric acid (UA) in bone metabolism is still debated. However, recent studies have shown that endogenous UA within the normal range may exert a positive effect in bone formation by means of its antioxidant role in both sexes. To date, no studies have been carried out in obese subjects aiming to study the relationship between serum OC and UA, given that obesity is considered as a risk factor for osteoporosis and fracture and, at the same time, for cardiovascular events. Our search purpose was to verify the relationship between endogenous levels of OC and serum UA in a cohort of obese subjects without any metabolic or chronic diseases (i.e. hypertension, renal failure, diabetes mellitus, etc.). One hundred and twenty one obese subjects (93 women and 28 men) were enrolled for this study. Serum OC and UA were assessed and compared with demographic characteristics, clinical and biochemical parameters (age, body mass index (BMI), blood pressure, waist circumference, serum lipids and glycaemia). Serum OC was directly and independently correlated with circulating UA in our population of obese subjects, while neither BMI, age, serum lipids, fasting glycaemia nor gender showed a statistically significant correlation with endogenous plasma levels of OC. The positive effect determined by serum OC in bone metabolism of our obese subjects might be partly due to the antioxidant properties that normal plasma UA levels exert at bone tissue level.

MicroRNA-138 directly targets TNFAIP8 and acts as a tumor suppressor in osteosarcoma.

MicroRNAs (miRs) have a critical role in the development and malignant progression of osteosarcoma (OS), but the underlying mechanisms have largely remained elusive. The present study aimed to explore the regulatory role of miR-138 in OS growth and metastasis and investigated the associated mechanisms. Reverse-transcription quantitative polymerase chain reaction and western blot analysis were performed to examine the miR-138 and protein expression levels in OS and normal bone tissues and cell lines. An MTT assay and a Transwell assay were used to assess cell proliferation and invasion. Flow cytometry was used to analyze the cell cycle and determine the apoptotic rate. A luciferase reporter assay was used to confirm the targeting association between miR-138 and tumor necrosis factor-α-induced protein 8 (TNFAIP8). It was found that miR-138 was downregulated in OS tissues and cell lines. Overexpression of miR-138 decreased the proliferation, cell cycle progression and invasion of OS cells, while inducing cell apoptosis. TNFAIP8 was then identified as a novel target of miR-138. Similarly to the effects of miR-138 overexpression, inhibition of TNFAIP8 also inhibited OS cell proliferation, cell cycle progression and invasion, and induced cell apoptosis. In addition, miR-138 overexpression as well as downregulation of TNFAIP8 reduced OS cell invasion via inhibition of matrix metalloproteinase-2 and −9 expression. Taken together, the results of the present study demonstrated that miR-138 directly targets TNFAIP8 and acts as a tumor suppressor in OS, suggesting that the miR-138/TNFAIP8 interaction may become a promising therapeutic target for OS.

Co-deteriorations of anisotropic extracellular matrix arrangement and intrinsic mechanical property in c-src deficient osteopetrotic mouse femur

Osteopetrotic bone shows dissociation between bone mineral density (BMD) and bone strength. In this study, volumetric BMD; preferential orientation of the extracellular matrix (ECM), which is composed of collagen fibers and apatite crystals as bone material quality; and mechanical properties of the src−/− osteopetrotic and normal mouse femoral cortical bone were analyzed and compared with each other at a bone tissue level. The degree of preferential orientation of ECM along the femoral long axis was significantly decreased in the src−/− mice femur, suggesting deteriorated bone quality. Young's modulus, as a tissue-level mechanical property analyzed by nano-indentation technique along the long bone direction, also was decreased in the src−/− mice cortical femur, in spite of the similar volumetric cortical BMD. To the best of our knowledge, this is the first report to demonstrate the synchronous deterioration of Young's modulus and anisotropic ECM organization in the src−/− osteopetrotic mouse bone. These results indicate that the deterioration of the preferential ECM orientation is one major cause of the impaired mechanical property in the src−/− mouse bone.

A Natural, Calcium-Rich Marine Multi-mineral Complex Preserves Bone Structure, Composition and Strength in an Ovariectomised Rat Model of Osteoporosis.

Calcium supplements are used as an aid in the prevention of osteopenia and osteoporosis and also for the treatment of patients when used along with medication. Many of these supplements are calcium carbonate based. This study compared a calcium-rich, marine multi-mineral complex (Aquamin) to calcium carbonate in an ovariectomised rat model of osteoporosis in order to assess Aquamin's efficacy in preventing the onset of bone loss. Animals were randomly assigned to either non-ovariectomy control (Control), ovariectomy (OVX) plus calcium carbonate, ovariectomy plus Aquamin or ovariectomy plus Aquamin delay where Aquamin treatment started 8weeks post OVX. At the end of the 20-week study, the trabecular architecture was measured using micro computed tomography, bone composition was assessed using Fourier transform infrared spectroscopy and the mechanical properties were assessed using nanoindentation and three-point bend testing. The study demonstrates that oral ingestion of Aquamin results in less deterioration of trabecular bone structure, mineral composition and tissue level biomechanical properties in the tibia of rats following ovariectomy than calcium carbonate. This study has shown that in an animal model of osteoporosis, Aquamin is superior to calcium carbonate at slowing down the onset of bone loss.

Comparative evaluation of the effectiveness of the implantation in the lateral part of the mandible between short tissue level (TE) and bone level (BL) implant systems

Short dental implants can be an alternative method of treatment to a vertical bone augmentation procedure at sites of reduced alveolar height. However, for successful treatment, an implant system that causes a minimal marginal bone loss (MBL) should be taken into consideration.The aim of the study has been to evaluate implantation effectiveness for bone level and tissue level short implants provided in lateral aspects of partially edentulous mandible and limited alveolar ridge height. The MBL and primary as well as secondary implant stability were determined in the study.Patients were randomly divided into two groups according to the method of treatment provided. Sixteen short Bone Level Implants (OsseoSpeed TX, Astra tech) and 16 short Tissue Level Implants (RN SLActive®, Straumann) were successfully placed in the edentulous part of the mandible. The determination of the marginal bone level was based on radiographic evaluation after 12 and 36 weeks. Implant stability was measured immediately after insertion and after 12 weeks.The marginal bone level of Bone Level Implants was significantly lower compared to Tissue Level Implants. Furthermore, the Bone Level Implants had greater primary and secondary stability in comparison with Tissue Level Implants (Primary: 77.8 ISQ versus 66.5 ISQ; Secondary: 78.9 ISQ versus 73.9 ISQ, respectively).Since short Bone Level Implants showed a significantly decreased MBL 12 and 36 weeks after implantation as well as better results for the primary stability compared to Tissue Level Implants, they should preferentially be used for this mentioned indication.