Impact of diabetes mellitus and metabolic control on bone healing around osseointegrated implants: removal torque and histomorphometric analysis in rats

Reduced osseointegration in disuse and denervation rat models results from impaired cellular responses to multiscale microstructured titanium surfaces

Immobilization-induced skeletal unloading results in muscle atrophy and rapid bone loss, thereby increasing the risk of falling and the need for implant therapy in patients with extended bed rest or neuromuscular injuries. Skeletal unloading causes bone loss by altering bone growth and resorption, suggesting that implant performance might be affected. To test this, we focused on early events in implant osseointegration. We used the rat sciatic neurectomy-induced disuse model under two different settings. In Study 1, 16 Sprague Dawley rats (SD) were separated into control, sham operated+cast immobilization, and sciatic neurectomy+casting groups; titanium implants with multiscale microtextured topography and hydrophilic chemistry (modSLA) were inserted in the distal femoral metaphysis. Neurectomy surgeries and casting were performed at the same surgical setting as implant placement; rats were euthanized 4 weeks post-implantation. In Study 2, we established the unloaded condition before implantation. A total of 12 SD rats were divided into control and sciatic+femoral neurectomy groups. A total of 24 days after sciatic and femoral neurectomy surgery, rats received implants. Study 2 rats were euthanized at 4 weeks post-implantation. MicroCT and histomorphometry showed that trabecular bone and osseointegration were reduced when disuse was established before implantation. Osteoblasts isolated from Study 1 sciatic neurectomy tibial bones exhibited impaired differentiation on modSLA culture disks, revealing a possible mechanism responsible for the decreased osseointegration observed in the Study 2 rats. This study addressed the importance of considering the mechanical unloading and muscle function history before implant insertion and suggests that implant performance was reduced due to poor cellular ability to regenerate.

Exosomes derived from impaired liver aggravate alveolar bone loss via shuttle of Fasn in type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) exacerbates irreversible bone loss in periodontitis, but the mechanism of impaired bone regeneration caused by the abnormal metabolic process of T2DM remains unclear. Exosomes are regarded as the critical mediator in diabetic impairment of regeneration via organ or tissue communication. Here, we find that abnormally elevated exosomes derived from metabolically impaired liver in T2DM are significantly enriched in the periodontal region and induced pyroptosis of periodontal ligament cells (PDLCs). Mechanistically, fatty acid synthase (Fasn), the main differentially expressed molecule in diabetic exosomes results in ectopic fatty acid synthesis in PDLCs and activates the cleavage of gasdermin D. Depletion of liver Fasn effectively mitigates pyroptosis of PDLCs and alleviates bone loss. Our findings elucidate the mechanism of exacerbated bone loss in diabetic periodontitis and reveal the exosome-mediated organ communication in the "liver-bone" axis, which shed light on the prevention and treatment of diabetic bone disorders in the future.

SATB1 promotes osteogenic differentiation of diabetic rat BMSCs through MAPK signalling activation

OBJECTIVE

Special AT-rich binding protein 1 (SATB1), a chromatin organizer and global transcriptional regulator, plays an important role in tumorigenesis and immune response. However, its function in the osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) remains unknown. Therefore, this study aimed to explore the role of SATB1 in osteogenesis.

METHODS

BMSCs were collected from the type 2 diabetes rat model and the protein and gene expression of SATB1 and osteospecific genes were evaluated post osteogenic induction.

RESULTS

SATB1 protein expression significantly decreased in diabetic rat BMSCs whereas it increased in BMSCs following osteogenic induction. SATB1 knockdown significantly suppressed the expression of osteospecific genes, including alkaline phosphatase (Alp), runt-related transcription factor 2, and osteocalcin, and reduced the number of mineral deposits and ALP activity, whereas SATB1 overexpression yielded the opposite results. Moreover, SATB1 knockdown suppressed activation of the MAPK signalling pathway (phosphorylation of p38 and ERK), and MAPK pathway inhibitors could reverse the inhibitory effect of SATB1 knockdown on osteogenic differentiation of BMSCs.

CONCLUSION

SATB1 plays a key role in the osteogenic differentiation of BMSCs via the p38 MAPK and ERK MAPK signalling pathways. These findings may provide a new strategy for the application of BMSCs in bone regeneration.

Zucker Diabetic-Sprague Dawley Rats Have Impaired Peri-Implant Bone Formation, Matrix Composition, and Implant Fixation Strength

An increasing number of patients with type 2 diabetes (T2DM) will require total joint replacement (TJR) in the next decade. T2DM patients are at increased risk for TJR failure, but the mechanisms are not well understood. The current study used the Zucker Diabetic-Sprague Dawley (ZDSD) rat model of T2DM with Sprague Dawley (SPD) controls to investigate the effects of intramedullary implant placement on osseointegration, peri-implant bone structure and matrix composition, and fixation strength at 2 and 10 weeks post-implant placement. Postoperative inflammation was assessed with circulating MCP-1 and IL-10 2 days post-implant placement. In addition to comparing the two groups, stepwise linear regression modeling was performed to determine the relative contribution of glucose, cytokines, bone formation, bone structure, and bone matrix composition on osseointegration and implant fixation strength. ZDSD rats had decreased peri-implant bone formation and reduced trabecular bone volume per total volume compared with SPD controls. The osseointegrated bone matrix of ZDSD rats had decreased mineral-to-matrix and increased crystallinity compared with SPD controls. Osseointegrated bone volume per total volume was not different between the groups, whereas implant fixation was significantly decreased in ZDSD at 2 weeks but not at 10 weeks. A combination of trabecular mineral apposition rate and postoperative MCP-1 levels explained 55.6% of the variance in osseointegration, whereas cortical thickness, osseointegration mineral apposition rate, and matrix compositional parameters explained 69.2% of the variance in implant fixation strength. The results support the growing recognition that both peri-implant structure and matrix composition affect implant fixation and suggest that postoperative inflammation may contribute to poor outcomes after TJR surgeries in T2DM patients. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Radioprotective role of amifostine on osteointegration of titanium implants in the tibia of rats

BACKGROUND

Titanium is the most widely used metal for bone integration, especially for cancer patients receiving ionizing radiation. This study aimed to investigate the amifostine administration that would reduce the effects of radiation on bone healing and osseointegration in rat models.

OBJECTIVES

It is aimed that the application of amifostine in rats receiving radiotherapy treatment will reduce the negative effects of ionizing radiation on the bone.

METHODS

Thirty-five adult male Wistar rats were randomly divided into one healthy and four experimental groups. In three consecutive days, two experimental groups of rats (AMF-RT-IMP and RT-IMP) were exposed to radiation (15 Gy/3 fractions of 5 Gy each). Then the titanium implants were inserted into the left tibia. Before the radiotherapy process, a 200 mg/kg dose of amifostine (AMF) was administered to the rats in the AMF-IMP and AMF-RT-IMP groups. Twenty-eight days after the screw implant, all rats were sacrificed, and their blood samples and tibia bones were collected for analysis.

RESULTS

The results indicated an accelerated bone formation and a more rapid healing process in the screw implants in the AMF-IMP, AMF-RT-IMP, and AMF-RT groups than in the RT-IMP group. Also, bone-implant contact area measurement and inflammation decreased with amifostine treatment in the implants subjected to irradiation (p < 0.05).

CONCLUSIONS

The results obtained in the present study suggested that amifostine prevents the losses of bone minerals, bone integrity, and implant position from ionizing-radiation when given before exposure.

Metabolic Conditions and Peri-Implantitis

Dental implants to replace lost teeth are a common dentistry practice nowadays. Titanium dental implants display a high success rate and improved safety profile. Nevertheless, there is an increasing peri-implantitis (PI), an inflammatory disease associated with polymicrobial infection that adversely affects the hard and soft tissues around the implant. The present review highlights the contribution of different metabolic conditions to PI. The considerations of both local and systemic metabolic conditions are crucial for planning successful dental implant procedures and during the treatment course of PI. Un- or undertreated PI can lead to permanent jaw bone suffering and dental implant losses. The common mediators of PI are inflammation and oxidative stress, which are also the key mediators of most systemic metabolic disorders. Chronic periodontitis, low-grade tissue inflammation, and increased oxidative stress raise the incidence of PI and the underlying systemic metabolic conditions, such as obesity, diabetes mellitus, or harmful lifestyle factors (cigarette smoking, etc.). Using dental biomaterials with antimicrobial effects could partly solve the problem of pathogenic microbial contamination and local inflammation. With local dentistry considering factors, including oral microbiota and implant quality control, the inclusion of the underlying systemic metabolic conditions into the pre-procedure planning and during the treatment course should improve the chances of successful outcomes.

Effect of Anti-Diabetic Medications on Dental Implants: A Scoping Review of Animal Studies and Their Relevance to Humans

Animal studies have ascertained that hyperglycemia adversely affects bone metabolism and dental implant osseointegration. However, diabetic patients show low occurrence of unfavorable hard or soft peri-implant tissue changes, differences that are possibly due to treatment with anti-diabetic medications. This scoping review aimed to systematically examine the effects of these drugs on implant outcomes and explore the predictive modality of animal studies for clinical practice according to type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM). Three electronic databases (MEDLINE, EBSCOHost, and Cochrane) were searched according to the PRISMA-ScR standards for studies on diabetic animals that received titanium implants and anti-diabetic treatments. Risk assessment was performed using the SYRCLE Risk-of-Bias (RoB) tool. Twenty-one papers were included, encompassing six types of medications. Fifteen studies were on T1DM animals, and only six involved T2DM models. T1DM animals were treated with non-insulin drugs in four investigations, while insulin was utilized in 11 other studies. In T2DM experiments, five administered non-insulin drugs, and only one applied locally delivered insulin. Only insulin in T1DM studies produced a positive influence on bone-implant contact (BIC), bone mineral content, and removal torque values. Inappropriate drug selection, inadequate glycemic control, and high RoB depict a mismatch between the research focus and the translational rationale to clinical practice. There remains a knowledge gap regarding T2DM investigations due to the lack of studies. More data are needed concerning intraoral implants and the performance of osseointegrated implants in patients with a later onset of diabetes. Future research should reflect the pathophysiology and treatment of each type of diabetes to ensure clinical applicability.

The impact of medication on osseointegration and implant anchorage in bone determined using removal torque-A review

Permanently anchored metal implants are frequently used in dental, craniomaxillofacial, and orthopaedic rehabilitation. The success of such therapies is owed to the phenomenon of osseointegration-the direct connection between the living bone and the implant. The extent of biomechanical anchorage (i.e., physical interlocking between the implant and bone) can be assessed with removal torque (RTQ) measurement. Implant anchorage is strongly influenced by underlying bone quality, involving physicochemical and biological properties such as composition and structural organisation of extracellular matrix, extent of micro-damage, and bone turnover. In this review, we evaluated the impact of various pharmacological agents on osseointegration, from animal experiments conducting RTQ measurements. In addition to substances whose antiresorptive and/or anti-catabolic effects on bone are well-documented (e.g., alendronate, zoledronate, ibandronate, raloxifene, human parathyroid hormone, odanacatib, and the sclerostin monoclonal antibody), positive effects on RTQ have been reported for substances that do not primarily target bone (e.g., aminoguanidine, insulin, losartan, simvastatin, bone morphogenetic protein, alpha-tocopherol, and the combination of silk fibroin powder and platelet-rich fibrin). On the contrary, several substances (e.g., prednisolone, cyclosporin A, cisplatin, and enamel matrix derivative) tend to adversely impact RTQ. While morphometric parameters such as bone-implant contact appear to influence the biomechanical anchorage, increased or decreased RTQ is not always accompanied by corresponding fluctuations in bone-implant contact. This further confirms that factors such as bone quality underpin biomechanical anchorage of metal implants. Several fundamental questions on drug metabolism and bioavailability, drug dosage, animal-to-human translation, and the consequences of treatment interruption remain yet unanswered.

Hormone and implant osseointegration: Elaboration of the relationship among function, preclinical, and clinical practice

As clusters of peptides or steroids capable of high-efficiency information transmission, hormones have been substantiated to coordinate metabolism, growth, development, and other physiological processes, especially in bone physiology and repair metabolism. In recent years, the application of hormones for implant osseointegration has become a research hotspot. Herein, we provide a comprehensive overview of the relevant reports on endogenous hormones and their corresponding supplementary preparations to explore the association between hormones and the prognosis of implants. We also discuss the effects and mechanisms of insulin, parathyroid hormone, melatonin, vitamin D, and growth hormone on osseointegration at the molecular and body levels to provide a foothold and guide future research on the systemic conditions that affect the implantation process and expand the relative contraindications of the implant, and the pre-and post-operative precautions. This review shows that systemic hormones can regulate the osseointegration of oral implants through endogenous or exogenous drug-delivery methods.

The effect of insulin and kruppel like factor 10 on osteoblasts in the dental implant osseointegration in diabetes mellitus patients

Diabetes mellitus, metabolic disease, is characterized by chronic hyperglycemia. Patients with diabetes mellitus are susceptible to infection and therefore have a higher prevalence and progression rate of periodontal disease. We aimed to study the effect of insulin and kruppel like factor 10 (KLF10) on osteoblasts proliferation and differentiation, and expression of bone metabolism-related molecules and related signaling pathway molecules of AKT serine/threonine kinase 1 (AKT) and nuclear factor kappa B subunit 1 (NF-κB) through in vitro experiments, which can provide theoretical basis for the dental implant osseointegration in diabetic patients. The osteoblasts (hFOB 1.19 cells) were subdivided into KLF10 gene over expression group, KLF10 gene knockdown group, and KLF10 gene knockdown + insulin treatment group. CCK-8 and ELISA were, respectively, used for analysis of cell proliferation and differentiation. In vitro experiments were applied to detect the mRNA and protein expression of bone metabolism-related molecules, respectively. GSE178351 dataset and GSE156993 dataset were utilized to explore the expression of KLF10 in periodontitis. In osteoblasts, insulin treatment increased the expression of KLF10. Insulin and KLF10 could reduce the proliferation and differentiation of osteoblasts. Knockdown of KLF10 could increase the expression of bone metabolism-related molecules and activate AKT and NF-κB pathways, whereas insulin reversed this effect. KLF10 was up-regulated in both patients with periodontitis and type 2 diabetes mellitus with periodontitis. It is assumed that knockdown of KLF10 in insulin resistance may promote osteoblasts differentiation and dental implant osseointegration in diabetic patients.

Impaired dental implant osseointegration in rat with streptozotocin-induced diabetes

OBJECTIVE

Few studies have reported on the impact of oxidative stress on the dental implant failure. The aim of this study was to investigate the impact of hyperglycemia-induced oxidative stress on dental implant osseointegration in diabetes mellitus (DM).

METHODS

Acid-treated titanium implants were bilaterally placed in the maxillary alveolar ridge of streptozotocin-induced diabetic (DM group) and control rats after extraction of first molars. Histological analysis and micro-push-out test were performed 4 weeks after surgery. Oxidative stress and osteogenic markers in the surrounding bone were quantified by real-time polymerase chain reaction. In the in vitro study, rat bone marrow-derived mesenchymal stem cells (BMMSCs) were cultured on acid-treated titanium discs in a high-glucose (HG) or normal environment. Intracellular reactive oxygen species (ROS), cell proliferation, alkaline phosphatase (ALP) activity, and extracellular calcification were evaluated following antioxidant treatment with N-acetyl-L-cysteine (NAC).

RESULTS

The implant survival rate was 92.9% and 75.0% in control and DM group, respectively. Bone-implant contact and push-out loads were significantly lower in the DM group. Expression of superoxide dismutase 1 at the mRNA level and on immunohistochemistry was significantly lower in the DM group. In vitro experiments revealed that the HG condition significantly increased ROS expression and suppressed the proliferation and extracellular calcification of BMMSCs, while NAC treatment significantly restored ROS expression, cell proliferation, and calcification. The ALP activity of both groups was not significantly different.

CONCLUSION

In diabetes, high-glucose-induced oxidative stress downregulates proliferation and calcification of BMMSCs, impairing osseointegration and leading to implant failure.

Pre-Clinical Models in Implant Dentistry: Past, Present, Future

Biomedical research seeks to generate experimental results for translation to clinical settings. In order to improve the transition from bench to bedside, researchers must draw justifiable conclusions based on data from an appropriate model. Animal testing, as a prerequisite to human clinical exposure, is performed in a range of species, from laboratory mice to larger animals (such as dogs or non-human primates). Minipigs appear to be the animal of choice for studying bone surgery around intraoral dental implants. Dog models, well-known in the field of dental implant research, tend now to be used for studies conducted under compromised oral conditions (biofilm). Regarding small animal models, research studies mostly use rodents, with interest in rabbit models declining. Mouse models remain a reference for genetic studies. On the other hand, over the last decade, scientific advances and government guidelines have led to the replacement, reduction, and refinement of the use of all animal models in dental implant research. In new development strategies, some in vivo experiments are being progressively replaced by in vitro or biomaterial approaches. In this review, we summarize the key information on the animal models currently available for dental implant research and highlight (i) the pros and cons of each type, (ii) new levels of decisional procedures regarding study objectives, and (iii) the outlook for animal research, discussing possible non-animal options.

Strontium-incorporated titanium implant surfaces treated by hydrothermal treatment enhance rapid osseointegration in diabetes: A preclinical vivo experimental study

OBJECTIVES

The aim of the current study was to explore effects of strontium-incorporated titanium implant surfaces by hydrothermal treatment on osseointegration in diabetic rats.

MATERIALS AND METHODS

The surface characteristics of SLA and SLA-Sr surfaces were detected by related instruments. Thirty-six male Sprague-Dawley rats were induced into diabetes, and thirty-six rats were normal. SLA and SLA-Sr implants were, respectively, inserted into bilateral tibial metaphysis of each rat. Percentage of bone-to-implant contact (BIC%) and percentage of bone area (BA%) were analyzed at 4 and 8 weeks after implantation. Immunohistochemistry of osteoprotegerin (OPG) and Wnt5a were conducted at 1 and 4 weeks. Gene expression levels of inflammatory cytokines and related signaling molecules in peri-implant bone tissue were detected at 3 and 7 days.

RESULTS

Strontium was uniformly distributed on SLA-Sr surfaces, and it was released in an effective concentration range. SLA-Sr surfaces showed significantly higher BIC% in diabetic rats at 4 (p < .05) and 8 weeks (p < .05). Besides, it displayed higher BIC% at 4 weeks (p < .05) in normal rats. Also, SLA-Sr surfaces upregulated expression of OPG at 4 weeks (p < .05) in diabetic rats. What's more, SLA-Sr surfaces downregulated inflammation (TNF-α, IL-1β, and IL-6; p < .01) in diabetic rats at 3 days. In addition, expression of Wnt5a and ROR2 was upregulated (p < .05) at 7 days after implantation under diabetes.

CONCLUSION

It is suggested that strontium-incorporated titanium implant surfaces by hydrothermal treatment could enhance implant osseointegration as compared with SLA implant surfaces in diabetic rats.

Impact of resveratrol in the reduction of the harmful effect of diabetes on peri-implant bone repair: bone-related gene expression, counter-torque and micro-CT analysis in rats

OBJECTIVE

Investigate the impact of resveratrol (RESV) on peri-implant repair and its effect on bone-related markers in rats with induced diabetes mellitus (DM).

MATERIAL AND METHODS

Ninety rats were divided into: DM + RESV (n = 18); DM + placebo (PLAC) (n = 18); DM + insulin (INS) (n = 18); DM + RESV + INS (n = 18); Non-DM (n = 18). Diabetes was induced by streptozotocin. One screw-shaped titanium implant was inserted in each tibiae of animals. Treatments were administered during 30 days. After, one of the implants was removed for counter-torque and the peri-implant tissue was collected for mRNA quantification of BMP-2, OPN, Runx2, Lrp-5, Osx, β-catenin, Dkk1, OPG, and RANKL by Real-time PCR. The other tibia was submitted to MicroCT analysis to measure: bone volume (BV/TV), trabecular thickness (Tb.Th) and bone-implant contact (BIC).

RESULTS

Higher counter-torque values were observed for implant removal in DM + RESV, DM + RESV + INS and Non-DM groups when compared to DM + PLAC (p < .05). Augmented Tb.Th was observed in DM + RESV and Non-DM when compared to DM + PLAC group (p < .05), whereas higher BIC was detected in DM + RESV, DM + RESV + INS and Non-DM animals when compared to DM + PLAC (p < .05). Levels of RANKL were downregulated by the RESV and/or INS therapy, whereas only the association of RESV and INS upregulated the levels of Runx2 (p < .05).

CONCLUSIONS

The therapy with RESV may favour peri-implant bone repair improving bone formation around implants.

Histomorphometric analysis of implant osseointegration using hydrophilic implants in diabetic rats

OBJECTIVES

To evaluate peri-implant bone formation of titanium implants using an in vivo rat model with and without uncontrolled diabetes mellitus (DM) to evaluate osseointegration of hydrophobic (Neoporos®) and hydrophilic (Acqua®) surfaces.

MATERIALS AND METHODS

54 rats were divided into two groups: DM group (DMG) (streptozotocin-induced diabetes) and a control group (CG). Implants with hydrophobic (Neoporos®) and hydrophilic surfaces (Acqua®) were placed in the left or right tibia of animals. Animals were further divided into three groups (n = 9) euthanized after 7, 14, or 28 days. Bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO) were assessed in total, cortical, and medullary areas.

RESULTS

The DMG group, after a 7-day healing period, yielded with the Acqua implants presented significantly higher total BIC (+37.9%; p=0.03) and trabecular BIC (%) (+46.3%; p=0.02) values in comparison to the Neoporos implants. After 28 days of healing, the CG yielded that the cortical BAFO of Acqua implants to be significantly, 14%, higher (p=0.04) than Neoporos implants.

CONCLUSION

The positive effects of the Acqua surface were able to counteract the adverse impact of uncontrolled DM at early osseointegration periods. After 28 days in vivo, the metabolic systemic impairment caused by DM overcame the surface treatment effect, leading to impaired osseointegration in both hydrophilic and hydrophobic implants.

CLINICAL RELEVANCE

The adverse effects of diabetes mellitus with respect to bone healing may be minimized by deploying implants with strategically modified surfaces. This study evaluated the effects of implants with Acqua® and Neoporos® surfaces in both diabetic and healthy animals. During the initial healing period in diabetic animals, the hydrophilic surface was demonstrated to have beneficial effect on osseointegration in comparison to the hydrophobic surface. The results provide an insight into early healing, but the authors suggest that a future short-term and long-term clinical study is needed to assess the possible benefit of the Acqua® implant as well as in increasing the predictability of implant osseointegration.

Development of a rat model for type 2 diabetes mellitus peri-implantitis: A preliminary study

OBJECTIVE

To develop an in vivo model to simulate the complex internal environment of diabetic peri-implantitis (T2DM-PI) model for a better understanding of peri-implantitis in type 2 diabetic patients.

MATERIALS AND METHODS

Maxillary first molars were extracted in Sprague-Dawley (SD) rats, and customized cone-shaped titanium implants were installed in the extraction sites. Thereafter, implants were uncovered and customized abutments were screwed into implants. A high-fat diet and a low-dose injection of streptozotocin were utilized to induce T2DM. Finally, LPS was locally injected in implant sulcus to induce peri-implantitis.

RESULTS

In the present study, T2DM-PI model has been successfully established. Imaging analysis revealed that abundant inflammatory cells infiltrated in the soft tissue in T2DM-PI group with concomitant excessive secretion of inflammatory cytokines. Moreover, higher expression of MMP and increased number of osteoclasts led to collagen disintegration and bone resorption in T2DM-PI group.

CONCLUSIONS

These results describe a novel rat model which stimulate T2DM-PI in vivo, characterized by overwhelming inflammatory response and bone resorption. This model has a potential to be used for investigation of initiation, progression and interventional therapy of T2DM-PI.

Genipin and insulin combined treatment improves implant osseointegration in type 2 diabetic rats

BACKGROUND

Type 2 diabetes mellitus (T2DM) has a harmful effect on the stability and osseointegration of dental implants. T2DM induces mitochondrial damage by inhibiting AMPK signaling, resulting in oxidative stress and poor osteogenesis in the peri-implant bone area. Genipin is a major component of gardenia fruits with strong antioxidant, anti-inflammation, and antidiabetic actions, and it also can activate mitochondrial quality control via the AMPK pathway. The purpose of this study was to investigate the effects of genipin and insulin treatment on implant osseointegration in T2DM rats and explore the underlying mechanisms.

METHODS

Streptozotocin-induced diabetic rats received implant surgery in their femurs and were then assigned to five groups that were subjected to different treatments for three months: control group, T2DM group, insulin-treated T2DM group (10 IU/kg), genipin-treated T2DM group (50 mg/kg), and the genipin and insulin combination-treated T2DM group. Then, we regularly assessed the weight and glucose levels of the animals. Rats were euthanized at 3 months after the implantation procedure, and the femora were harvested for microscopic computerized tomography analysis, biomechanical tests, and different histomorphometric assessment.

RESULTS

The results indicated that the highest blood glucose and oxidative stress levels were measured for the T2DM group, resulting in the poorest osseointegration. The combination-treated T2DM group mitigated hyperglycemia and normalized, reactivated AMPK signaling, and alleviated oxidative stress as well as reversed the negative effect of osseointegration. There were beneficial changes observed in the T2DM-genipin and T2DM-insulin groups, but these were less in comparison to the combination treatment group.

CONCLUSION

Our study suggests that treatment with genipin in combination with insulin could be an effective method for promoting implant osseointegration in T2DM rats, which may be related to AMPK signaling.

Osseointegration Pharmacology: A Systematic Mapping Using Artificial Intelligence

Clinical performance of osseointegrated implants could be compromised by the medications taken by patients. The effect of a specific medication on osseointegration can be easily investigated using traditional systematic reviews. However, assessment of all known medications requires the use of evidence mapping methods. These methods allow assessment of complex questions, but they are very resource intensive when done manually. The objective of this study was to develop a machine learning algorithm to automatically map the literature assessing the effect of medications on osseointegration. Datasets of articles classified manually were used to train a machine-learning algorithm based on Support Vector Machines. The algorithm was then validated and used to screen 599,604 articles identified with an extremely sensitive search strategy. The algorithm included 281 relevant articles that described the effect of 31 different drugs on osseointegration. This approach achieved an accuracy of 95%, and compared to manual screening, it reduced the workload by 93%. The systematic mapping revealed that the treatment outcomes of osseointegrated medical devices could be influenced by drugs affecting homeostasis, inflammation, cell proliferation and bone remodeling. The effect of all known medications on the performance of osseointegrated medical devices can be assessed using evidence mappings executed with highly accurate machine learning algorithms.

Evaluation of pulsed electromagnetic field protocols in implant osseointegration: in vivo and in vitro study

OBJECTIVES

The present study aims to evaluate two protocols of pulsed electromagnetic field (PEMF) on osseointegration and establish one that addresses ideal parameters for its use in dentistry, especially in the optimization of the implants osseointegration process.

MATERIALS AND METHODS

Sixty male rats (Wistar) were allocated into three experimental groups: control (GC), test A (GTA, 3 h exposed), and test B (GTB, 1 h exposed). All animals received titanium implants in both tibias, and PEMF application (15 Hz, ± 1 mT, 5 days/week) occurred only in the test groups. They were euthanized at 03, 07, 21, and 45 days after PEMF therapy. Removal torque, histomorphometric measurements, three-dimensional radiographic evaluation, and in vitro biological assay analyses were performed.

RESULTS

GTB showed better results compared with GTA in removal torque tests, in bone volume and bone mineral density, cell viability, total protein content, and mineralization nodules (p < 0.05). GTA showed better performance in trabecular bone thickness and cell proliferation compared with GTB (p < 0.05), especially at osseointegration early periods. In the histomorphometric analysis and number of trabeculae, there were no differences in the test groups.

CONCLUSION

PEMF as a biostimulator was effective in optimizing the events in bone tissue that lead to osseointegration, especially when applied for a shorter time and in the initial periods of bone healing.

CLINICAL RELEVANCE

The PEMF therapy is an effective alternative method for optimizing bone healing.

The role of TiO2 nanotube surface on osseointegration of titanium implants: Biomechanical and histological study in rats

The nanoscale surface of titanium has been studied to improve the cellular recognition of the biological microenvironment and to increase bone-implant interaction. The aim of this study was to analyze the effect of a titanium oxide (TiO₂ ) nanotube surface with a machined surface on osseointegration tibia implants without primary stability. This study used an experimental design, divided into two groups (n = 16): commercially pure titanium machined implants (Cp-Ti Ma) and commercially pure titanium anodized implants (Cp-Ti An). Titanium nanotubes were produced by anodic oxidation, and the topography of surface was analyzed using field emission scanning microscope (FE-SEM). The implants (2.1 × 2.8 mm Ø) were surgically placed in the right tibia (defects with milling drill 2.5 × 3.2 mm Ø) of 32 Wistar male rats (250-300 g). The animals were euthanized at 7 weeks postoperatively. The maximum value of removal torque was measured (N/cm) in the right tibia half of each group (8 animals/8 tibiae); the other half of each group underwent a nondecalcified protocol, stained with Stevenel blue/Alizarin red, and the formation of bone tissue in close contact to the implant was measured. The obtained data were analyzed statistically (t test). Differences were considered statistically significant for α < 0.05. Cp-Ti An implants were significantly higher in removal torque and peri-implant bone healing compared with Cp-Ti Ma implants (p < .01). Within the limitations of this study, it was observed that the surface modification of titanium by anodization (TiO₂ nanotubes) can improve osseointegration, and this may be very useful to reduce the time required for peri-implant bone formation.

Hyperglycemia compromises Rat Cortical Bone by Increasing Osteocyte Lacunar Density and Decreasing Vascular Canal Volume

Uncontrolled diabetes is associated with increased risk of bony fractures. However, the mechanisms have yet to be understood. Using high-resolution synchrotron micro-CT, we calculated the changes in the microstructure of femoral cortices of streptozotocin-induced hyperglycemic (STZ) Wistar Albino rats and tested the mechanical properties of the mineralized matrix by nanoindentation. Total lacunar volume of femoral cortices increased in STZ group due to a 9% increase in lacunar density. However, total vascular canal volume decreased in STZ group due to a remarkable decrease in vascular canal diameter (7 ± 0.3 vs. 8.5 ± 0.4 µm). Osteocytic territorial matrix volume was less in the STZ group (14,908 ± 689 µm³) compared with healthy controls (16,367 ± 391 µm³). In conclusion, hyperglycemia increased cellularity and lacunar density, decreased osteocyte territorial matrix, and reduced vascular girth, in addition to decreasing matrix mechanical properties in the STZ group when compared with euglycemic controls.

Birol Ay et al. use high-resolution synchrotron radiation micro-CT to calculate the changes in the microstructure of femoral cortices in STZ-induced hyperglycemic rats. They show that hyperglycemia increases lacunar density due to a reduction in osteocytic territorial matrix volume but decreases total vascular canal volume due to a decrease in canal diameter.

Current Knowledge Regarding the Interaction Between Oral Bone Metabolic Disorders and Diabetes Mellitus

Diabetes mellitus, a major chronic disease affecting human health, has been increasing in prevalence in recent years. Diabetes mellitus can cause bone metabolic disorders in patients, leading to osteoporosis, a higher risk of traumatic fracture, and other bone diseases. Bone metabolic disorders in the oral cavity principally manifest as periodontitis, loss of alveolar bone, and failure of implant osseointegration. In recent years, numerous studies have shown that there is a complex interaction between bone metabolic disorders and diabetes mellitus. This paper reviews the adverse effects of diabetes on oral bone metabolism disorders such as alveolar osteoporosis and bone loss in patients with periodontitis, discusses the potential mechanisms of diabetic bone loss, and suggests potential ways to prevent and treat oral bone loss in patients with diabetes mellitus.

Bone regeneration in diabetic patients. A systematic review

Background

Oral bone regeneration techniques (OBRT) attempt to provide the appropriate bone volume and density to correctly accomplish dental implant treatments. The objective was to determine whether differences exist in the clinical outcomes of these techniques between diabetic and non-diabetic patients, considering the level of scientific evidence.

Material and Methods

A systematic review following PRISMA statements was conducted in the PubMed, Scopus and Cochrane databases with the search terms: “Diabetes Mellitus”, “guided bone regeneration”, “bone regeneration”, “alveolar ridge augmentation”, “ridge augmentation”, bone graft*, “sinus floor augmentation”, “sinus floor elevation”, “sinus lift”, implant*. Articles were limited to those published less than 10 years ago and in English. Inclusion criteria were: human studies of all bone regeneration techniques, including at least 10 patients and the using OBRT in diabetic and non-diabetic patients. Non-human studies were excluded. They were stratified according to their level of scientific evidence related to SORT criteria (Strength of Recommendation Taxonomy).

Results

The initial search provided 131 articles, after reading the abstracts a total of 33 relevant articles were selected to read the full text and analyzed to decide eligibility. Finally, seven of them accomplished the inclusion criteria: two controlled clinical trials, one cohort study and four case series.

Conclusions

A low grade of evidence regarding the use of OBRT in diabetic patients was found. The recommendation for this intervention in diabetic patients is considered type C due to the high heterogeneity of the type of diabetic patients included and the variability of the techniques applied.

Key words:Diabetes Mellitus, guided bone regeneration, bone regeneration.

Evaluation of L-PRF combined with deproteinized bovine bone mineral for early implant placement after maxillary sinus augmentation: A randomized clinical trial

PURPOSE

To investigate the effectiveness of adding leukocyte and platelet-rich fibrin (L-PRF) to deproteinized bovine bone mineral (DBBM) for early implant placement after maxillary sinus augmentation.

MATERIALS AND METHODS

Twelve patients requiring two-stage bilateral maxillary sinus augmentation were enrolled to the study. The elevated sinus cavities were randomly grafted with DBBM + L-PRF (test) or DBBM alone (control) in a split-mouth design. Implants were placed in the augmented sites after 4 months in the test group and 8 months in the control group. Bone biopsies were collected during implant placement for histomorphometric evaluation. Resonance frequency analysis was performed immediately after implant placement and at implant loading in both groups. Cone-beam computed tomography was obtained preoperatively and postoperatively for evaluation of graft volume changes.

RESULTS

Both procedures were effective for maxillary sinus augmentation. Cone-beam computed tomography analysis did not reveal differences in graft volume between test and control group at any of the evaluated time points (P > .05). Histological evaluation demonstrated increased percentage of newly formed bone for the test group (44.58% ± 13.9%) compared to the control group (30.02% ± 8.42%; P = .0087). The amount of residual graft in the control group was significantly higher (13.75% ± 9.99%) than in the test group (3.59 ± 4.22; P = .0111). Implant stability quotient (ISQ) immediately after implant placement was significantly higher in the control group (75.13 ± 5.69) compared to the test group (60.9 ± 9.35; P = .0003). The ISQ values at loading did not differ between the groups (P = .8587). Implant survival rate was 100% for both groups.

CONCLUSION

The addition of L-PRF to the DBBM into the maxillary sinus allowed early implant placement (4 months) with increased new bone formation than DBBM alone after 8 months of healing.

A randomized clinical trial evaluating maxillary sinus augmentation with different particle sizes of demineralized bovine bone mineral: histological and immunohistochemical analysis

This study was performed to investigate sinus floor augmentation with two different particle sizes of demineralized bovine bone mineral (DBBM) by means of histological and immunohistochemical (IHC) analysis. A randomized clinical trial was conducted involving 10 individuals requiring two-stage bilateral maxillary sinus augmentation for implant installation. The patients were randomly divided into two groups following a split-mouth design: the maxillary sinus on one side was filled with small-sized particles (0.25-1mm) and on the contralateral side with large-sized particles (1-2mm). After a healing period of 8 months, 25 implants were placed. During implant site preparation, bone biopsies were obtained from each sinus, perpendicular to the long axis of the implant (buccal-palatal direction), for descriptive and histomorphometric analyses. IHC staining for protein expression of osteocalcin (OCN), vascular endothelial growth factor (VEGF), and tartrate-resistant acid phosphatase (TRAP) was also performed. Histomorphometric analysis revealed no statistically significant difference in the percentage of biomaterial (32.4±8.56% and 38.0±6.92%), newly formed bone (36.1±9.60% and 36.7±5.79%), or connective tissue (30.4±8.63% and 23.8±6.16%) between the small- and large-sized particle groups, respectively. IHC analysis did not reveal differences in the expression of OCN, VEGF, or TRAP. These findings suggest that both particle sizes of DBBM are effective for bone augmentation in the maxillary sinus.

Effects of hyperbaric oxygen treatment on implant osseointegration in experimental diabetes mellitus

Objective

To evaluate whether hyperbaric oxygen (HBO) treatment has a favorable effect on implant osseointegration in diabetic rabbits.

Material and Methods

An experimental diabetes model was induced in 32 New Zealand rabbits through IV injection of alloxan. After the state of diabetes had been confirmed, one dental implant was placed in the metaphysical region of each animal’s tibia. After the implants’ placements, the animals were divided into two groups. Half of the animals underwent HBO treatment, while the other group did not receive HBO treatment and served as the control group. The animals were euthanized at the 4^th and 8^th weeks. The osseointegration of the implants were compared by histomorphometry and resonance frequency analysis (RFA).

Results

The Bone Implant Contact (BIC) values were significantly higher in the HBO group than in the control group at the 4th week. There was no difference in the BIC values between the groups at the 8th week. There was no significant difference in the RFA scores between the groups both at the 4^th and 8^th weeks after the operation.

Conclusion

Histomorphometry findings suggest that HBO has positive effect on implant osseointegration in the early healing period in diabetic rabbits. However, implant stability is not affected by HBO treatment.

Effect of curcumin on bone tissue in the diabetic rat: repair of peri-implant and critical-sized defects

This study determined the effect of curcumin on bone healing in animals with diabetes mellitus (DM). One hundred rats were divided into five groups: DM+PLAC, DM+CURC, DM+INS, DM+CURC+INS, and non-DM (CURC, curcumin; PLAC, placebo; INS, insulin). Critical calvarial defects were created and titanium implants were inserted into the tibiae. Calvarial defects were analyzed histometrically, and BMP-2, OPN, OPG, RANKL, Runx2, Osx, β-catenin, Lrp-5, and Dkk1 mRNA levels were quantified by PCR. The implants were removed for a torque evaluation, the peri-implant tissue was collected for mRNA quantification of the same bone-related markers, and the tibiae were submitted to micro-computed tomography. The DM+CURC+INS and non-DM groups exhibited greater closure of the calvaria when compared to the DM+PLAC group (P<0.05). Increased retention of implants was observed in the DM+CURC, DM+CURC+INS, and non-DM groups when compared to the DM+PLAC group (P<0.05). CURC improved bone volume and increased bone-implant contact when compared to DM+PLAC (P<0.05). In calvarial samples, CURC favourably modulated RANKL/OPG and Dkk1 and improved β-catenin levels when compared to DM+PLAC (P<0.05). In peri-implant samples, Dkk1 and RANKL/OPG were down-regulated and BMP-2 up-regulated by CURC when compared to DM+PLAC (P<0.05). CURC reverses the harmful effects of DM in bone healing, contributing to the modulation of bone-related markers.

Early Placement of Dental Implants in Maxillary Sinus Grafted With Leukocyte and Platelet-Rich Fibrin and Deproteinized Bovine Bone Mineral

This case report aimed to describe the effects of leukocyte and platelet-rich fibrin (L-PRF) associated with demineralized bovine bone mineral (DBBM) and absorbable collagen membrane (CM) on bone regeneration in maxillary sinus augmentation. A 59-year-old male patient was referred to the Department of Periodontology for implant rehabilitation of his edentulous upper jaw. The treatment plan involved maxillary sinus augmentation followed by implant installations. A split-mouth design was employed in which the right maxillary sinus was filled using L-PRF, DBBM, and CM; the left side was filled with DBBM and CM. After 4 and 8 months postoperatively, 2 dental implants were installed in each of the right and left maxillary sinuses. Cone-beam computerized tomography (CBCT) was taken before and after sinus augmentation for evaluation of tridimensional bone volume alterations. Bone biopsies were harvested from the implant sites for histomorphometric evaluation. Resonance frequency analysis was employed immediately after implant placement and before prosthetic rehabilitation for evaluation of implant stability. Implants were loaded 10 months after sinus augmentation. CBCT analysis showed a higher resorption rate in the right side of the maxillary sinus (L-PRF + DBBM) compared to the left side (22.25% and 8.95%, respectively). Implant stability quotients were above 68 in all time-points for both groups. Histomorphometric analysis showed a high amount of newly formed bone when L-PRF was used compared with DBBM alone (2 118 102 and 975 535 mm³, respectively). Taken together, both techniques were effective for maxillary sinus augmentation, however the addition of L-PRF to the graft allowed early implant placement and accelerated bone healing in the conditions studied.

Effect of Resveratrol on Critical-Sized Calvarial Defects of Diabetic Rats: Histometric and Gene Expression Analysis

PURPOSE

This study investigated the influence of resveratrol (RESV) on the repair of bone critical defects in calvaria of animals with induced diabetes mellitus (DM).

MATERIAL AND METHODS

One hundred rats were divided into 5 groups: induced DM + RESV administration (DM + RESV; n = 20); induced DM plus placebo solution administration (DM + PLAC; n = 20); induced DM plus insulin therapy (DM + INS; n = 20); induced DM plus administration of RES and INS (DM + RESV + INS; n = 20); and nondiabetic controls (NDM; n = 20). DM was induced by intraperitoneal injection of streptozotocin 50 mg/kg 3 days before the surgical procedures. Two critical calvarial defects were created in each animal at the start of the study (day 0). Treatments were administered from day 0 to day 30 of the experiment, when animals were euthanized. One defect was processed for histometric analysis to measure closure of the bone defect. The tissue of the other defect was analyzed for quantification of bone morphogenetic protein-2 (BMP-2), osteopontin, osteoprotegerin, receptor activator of nuclear factor-κB ligand, runt-related transcription factor-2, osterix (Osx), β-catenin, lipoprotein receptor-related protein-5, and dikkop-1 mRNA by quantitative polymerase chain reaction.

RESULTS

Histometric results showed that the DM + RESV, DM + RESV + INS, and NDM groups exhibited greater closure of the bone defects compared with the PLAC- or INS-treated groups (P < .05). Diabetic animals treated with RESV plus INS showed higher levels of BMP-2 and Osx; Osx also was positively increased in animals treated with INS alone (P < .05).

CONCLUSIONS

The use of RESV, regardless of the presence of INS, positively influenced bone repair in animals with induced DM. Further, the combination of INS plus RESV was necessary for the modulation of BMP-2 gene expression.

Effects of glucose concentration on osteogenic differentiation of type II diabetes mellitus rat bone marrow-derived mesenchymal stromal cells on a nano-scale modified titanium

BACKGROUND AND OBJECTIVE

Diabetes mellitus (DM) is a common disease worldwide. Patients with DM have an increased risk of losing their teeth compared with other individuals. Dental implants are a standard of care for treating partial or full edentulism, and various implant surface treatments have recently been developed to increase dental implant stability. However, some studies have reported that DM reduces osseointegration and the success rate of dental implants. The purpose of this study was to determine the effects of high glucose levels for hard tissue formation on a nano-scale modified titanium surface.

MATERIAL AND METHODS

Titanium disks were heated at 600°C for 1 h after treatment with or without 10 m NaOH solution. All disks were incubated with type II DM rat bone marrow-derived mesenchymal stromal cells before exposure to one of four concentrations of glucose (5.5, 8.0, 12.0 or 24.0 mm). The effect of different glucose concentrations on bone marrow-derived mesenchymal stromal cell osteogenesis and inflammatory cytokines on the nano-scale modified titanium surface was evaluated.

RESULTS

Alkaline phosphatase activity decreased with increasing glucose concentration. In contrast, osteocalcin production and calcium deposition were significantly decreased at 8.0 mm glucose, but increased with glucose concentrations over 8.0 mm. Differences in calcium/phosphate ratio associated with the various glucose concentrations were similar to osteocalcin production and calcium deposition. Inflammatory cytokines were expressed at high glucose concentrations, but the nano-scale modified titanium surface inhibited the effect of high glucose concentrations.

CONCLUSION

High glucose concentration increased hard tissue formation, but the quality of the mineralized tissue decreased. Furthermore, the nano-scale modified titanium surface increased mineralized tissue formation and anti-inflammation, but the quality of hard tissue was dependent on glucose concentration.

Comparison of periodontal and peri-implant inflammatory parameters among patients with prediabetes, type 2 diabetes mellitus and non-diabetic controls

OBJECTIVE

The aim was to compare periodontal and periimplant inflammatory parameters (plaque index [PI], bleeding on probing [BOP], probing depth [PD] and marginal bone loss [MBL]) among patients with prediabetes, type-2 diabetes mellitus (T2DM) and non-diabetic controls.

MATERIALS AND METHODS

Forty-five patients with prediabetes (Group-1), 43 patients with T2DM (Group-2) and 42 controls (Group-3) were included. Demographic data was recorded using a questionnaire. Full mouth and periimplant clinical (PI, BOP and PD) were assessed and the radiographic MBL were measured on digital radiographs. In all groups, haemoglobin A1c (HbA1c) levels were also measured. p values less than .05 were considered statistically significant.

RESULTS

The mean HbA1c levels of participants in groups 1, 2 and 3 were 6.1%, 8.4% and 4.8%, respectively. The mean duration of prediabetes and T2DM among patients in groups 1 and 2 were 1.9 ± 0.3 and 3.1 ± 0.5 years, respectively. Periodontal and periimplant PI, BOP, PD and MBL were higher in groups 1 (p < .05) and 2 (p < .05) than group 3. There was no difference in these parameters in groups 1 and 2.

CONCLUSIONS

Periodontal and periimplant inflammatory parameters were worse among patients with prediabetes and T2DM compared with controls; however, these parameters were comparable among patients with prediabetes and T2DM.

The effect of hyperglycaemia on osseointegration: a review of animal models of diabetes mellitus and titanium implant placement

Patients with type 2 diabetes mellitus have a higher risk of dental and/or orthopaedic implant failure. However, the mechanism behind this phenomenon is unclear, and animal studies may prove useful in shedding light on the processes involved. This review considers the available literature on rat models of diabetes and titanium implantation.

INTRODUCTION

The process of osseointegration whereby direct contact is achieved between bone and an implant surface depends on healthy bone metabolism. Collective evidence suggests that hyperglycaemia adversely affects bone turnover and the quality of the organic matrix resulting in an overall deterioration in the quality, resilience and structure of the bone tissue. This in turn results in compromised osseointegration in patients receiving dental and orthopaedic implants. The incidence of diabetes mellitus (DM), which is a chronic metabolic disorder resulting in hyperglycaemia, is rising. Of particular significance is the rising incidence of adult onset type 2 diabetes mellitus (T2DM) in an ageing population. Understanding the effects of hyperglycaemia on osseointegration will enable clinicians to manage health outcomes for patients receiving implants. Much of our understanding of how hyperglycaemia affects osseointegration comes from animal studies.

METHODS

In this review, we critically analyse the current animal studies.

RESULTS

Our review has found that most studies used a type 1 diabetes mellitus (T1DM) rodent model and looked at a young male population of rodents. The pathophysiology of T1DM is however very different to that of T2DM and is not representative of T2DM, the incidence of which is rising in the ageing adult population. Genetically modified rats have been used to model T2DM, but none of these studies have included female rats and the metabolic changes in bone for some of these models used are not adequately characterized.

CONCLUSIONS

Therefore, the review suggests that the study population needs to be broadened to include both T1DM and T2DM models, older rats as well as young rats, and importantly animals from both sexes to reflect more accurately clinical practice.

High glucose prevents osteogenic differentiation of mesenchymal stem cells via lncRNA AK028326/CXCL13 pathway

BACKGROUND

High glucose (HG) often induces unfavorable effects on proliferation and differentiation of mesenchymal stem cells (MSCs). This study aimed to explore potential molecular pathways underlying HG functional mechanism during osteogenic differentiation of MSCs, involving lncRNA AK028326 and CXCL13.

METHODS

Murine bone marrow-derived MSCs were cultured in osteogenic-inducing medium supplemented with high glucose level at 25mM or 5.5mM as normal control. Expression levels of lncRNA AK028326 and CXCL13 were measured by using real-time PCR. The mineralized nodule formation and alkaline phosphatase (ALP) activity were detected after 21 and 7days of incubation respectively. Western blot were also performed to determine the expression of CXCL13 and osteogenic gene markers. Plasmid pcDNAs and small interference RNAs were transfected as indicated for functional analysis of AK028326 and CXCL13.

RESULTS

HG suppressed the expression of AK028326 and CXCL13 in MSCs in a time-dependent manner, and also the mineralization, ALP activity, and osteogenic gene expression, which could be reversed by overexpression of AK028326 or CXCL13. CXCL13 expression was positively regulated by AK028326 at both mRNA and protein levels. Moreover, CXCL13 mediated the positive regulation of AK028326 on osteogenic gene expression in MSCs and MC3T3-E1 cells, mineralization and ALP activity in MSCs and also HG-induced inhibitory effects during MSCs differentiation into osteoblast.

CONCLUSION

HG could inhibit osteogenic differentiation of MSCs via inhibited expression of CXCL13 mediated by lncRNA AK028326, thereby providing new insights into the molecular mechanism of many osteogenesis-related diseases especially for patients with hyperglycemia.

Implant stability after sinus floor augmentation with deproteinized bovine bone mineral particles of different sizes: a prospective, randomized and controlled split-mouth clinical trial

The aim of this study was to compare implant stability after maxillary sinus floor augmentation using small- or large-sized particles of Bio-Oss. Ten partially edentulous patients requiring bilateral maxillary sinus floor augmentation were enrolled. The subjects were assigned randomly to one of two experimental groups: maxillary sinus was filled with 0.25-1mm particle size (small particles) and the contralateral side was filled with 1-2mm particle size (large particles). After 8 months, a total of 25 implants were placed in the two maxillary sinuses. Primary implant stability was measured immediately after implant placement (T0) using a torque controller and resonance frequency analysis (RFA). Six months after implant placement (T1), the implant stability was measured again. There were no postoperative complications in either particle size group, and the success rate for implant survival was 100%. All implants showed good primary stability as evidenced by high torque for the implant insertion in both groups. RFA revealed high ISQ values for all implants installed in both groups at T0 and T1. These results indicate that the size of the Bio-Oss particles (small and large) did not influence implant stability in the maxillary sinus. Indeed, small and large particles of Bio-Oss presented optimal properties, supporting their possible use as osteoconductive grafts.

Evaluation of bone substitutes for treatment of peri-implant bone defects: biomechanical, histological, and immunohistochemical analyses in the rabbit tibia

Purpose

We sought to evaluate the effectiveness of bone substitutes in circumferential peri-implant defects created in the rabbit tibia.

Methods

Thirty rabbits received 45 implants in their left and right tibia. A circumferential bone defect (6.1 mm in diameter/4 mm depth) was created in each rabbit tibia using a trephine bur. A dental implant (4.1 mm × 8.5 mm) was installed after the creation of the defect, providing a 2-mm gap. The bone defect gaps between the implant and the bone were randomly filled according to the following groups: blood clot (CO), particulate Bio-Oss^® (BI), and Bio-Oss^® Collagen (BC). Ten animals were euthanized after periods of 15, 30, and 60 days. Biomechanical analysis by means of the removal torque of the implants, as well as histologic and immunohistochemical analyses for protein expression of osteocalcin (OC), Runx2, OPG, RANKL, and TRAP were evaluated.

Results

For biomechanics, BC showed a better biological response (61.00±15.28 Ncm) than CO (31.60±14.38 Ncm) at 30 days. Immunohistochemical analysis showed significantly different OC expression in CO and BC at 15 days, and also between the CO and BI groups, and between the CO and BC groups at 60 days. After 15 days, Runx2 expression was significantly different in the BI group compared to the CO and BC groups. RANKL expression was significantly different in the BI and CO groups and between the BI and BC groups at 15 days, and also between the BI and CO groups at 60 days. OPG expression was significantly higher at 60 days postoperatively in the BI group than the CO group.

Conclusions

Collectively, our data indicate that, compared to CO and BI, BC offered better bone healing, which was characterized by greater RUNX2, OC, and OPG immunolabeling, and required greater reversal torque for implant removal. Indeed, along with BI, BC presents promising biomechanical and biological properties supporting its possible use in osteoconductive grafts for filling peri-implant gaps.

Facial and occlusal esthetic improvements of an adult skeletal Class III malocclusion using surgical, orthodontic, and implant treatment

The aim of this clinical report is to describe the complex treatment of an adult Class III malocclusion patient who was disappointed with the outcome of a previous oral rehabilitation. Interdisciplinary treatment planning was performed with a primary indication for implant removal because of marginal bone loss and gingival recession, followed by orthodontic and surgical procedures to correct the esthetics and skeletal malocclusion. The comprehensive treatment approach included: (1) implant removal in the area of the central incisors; (2) combined orthodontic decompensation with mesial displacement and forced extrusion of the lateral incisors; (3) extraction of the lateral incisors and placement of new implants corresponding to the central incisors, which received provisional crowns; (4) orthognathic surgery for maxillary advancement to improve occlusal and facial relationships; and finally, (5) orthodontic refinement followed by definitive prosthetic rehabilitation of the maxillary central incisors and reshaping of the adjacent teeth. At the three-year follow-up, clinical and radiographic examinations showed successful replacement of the central incisors and improved skeletal and esthetic appearances. Moreover, a Class II molar relationship was obtained with an ideal overbite, overjet, and intercuspation. In conclusion, we report the successful esthetic anterior rehabilitation of a complex case in which interdisciplinary treatment planning improved facial harmony, provided gingival architecture with sufficient width and thickness, and improved smile esthetics, resulting in enhanced patient comfort and satisfaction. This clinical case report might be useful to improve facial esthetics and occlusion in patients with dentoalveolar and skeletal defects.

Cyst decreased in size post maxillary sinus floor augmentation surgery in diabetic patient: A case report

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2.37 mm from the ridge to sinus floor with cyst (18.72 mm × 24.61 mm) firmly attached to the wall.

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Lateral approach to elevate the sinus floor with cyst simultaneously in diabetic patient.

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Osseointegration was achieved and the cyst decreased in size 6 months later.

Introduction

Whether mucosal cyst of maxillary sinus is contraindication for sinus floor augmentation surgery has been a controversial hot spot for years.

Presentation of case

This case aims to present the surgical procedure of sinus floor augmentation surgery with cyst (18.72 mm × 24.61 mm) in diabetic patient. And 6 months later, the cyst decreased in size. The authors elevated the sinus floor and cyst simultaneously. The surgery was carried out successfully without sinus membrane perforation and the alveolar ridge gained about 8 mm height. Six months later, the cyst decreased in size and osseointegration was observed.

Discussion

Interdisciplinary cooperation is encouraged to diagnose benign mucosal cyst. The isolation between sinus lumen and the grafted sub-sinus space is important. Graft contamination or dispersion into the sinus lumen should be avoided. The integrity of the sinus membrane and use of antibiotics are very important to prevent the occurrence of postoperative sinus infection

Conclusion

The authors conclude that sinus augmentation surgery could be done with mucosal cyst in diabetic patient.

Functionalization of titanium implants using a modular system for binding and release of VEGF enhances bone-implant contact in a rodent model

AIMS

To test the immobilization of vascular endothelial growth factor (VEGF165 ) on the surface of titanium implants using DNA oligonucleotide (ODN) anchor strands for the ability to enhance periimplant bone formation.

MATERIALS AND METHODS

DNA oligonucleotides were anchored to the surface of sandblasted acid-etched (SAE) titanium screw implants and were hybridized with complementary strands of ODN conjugated to rhVEGF165 . The implants were tested against blank SAE implants and SAE implants with nano-anchored ODN. The implants were inserted into the tibiae of 36 Sprague-Dawley rats. Primary outcome parameters were bone-implant contact (BIC), amount of new bone formation and periimplant bone density (BD). density after 1, 4 and 13 weeks. Unit of analysis has been the individual implant.

RESULTS

Implants with rhVEGF165 hybridized to ODN anchor strands exhibited significantly increased average BIC after 1 month compared to blank implants and implants with anchored ODN strands.

CONCLUSIONS

It is concluded that rhVEGF165 immobilized on the surface of titanium implants through nano-anchored oligonucleotide strands can accelerate BIC of sandblasted and etched titanium implants to a certain extent. The radius of effect of the growth factor appears to be limited to tissue immediately adjacent to the implant surface.

Insulin improves osteogenesis of titanium implants under diabetic conditions by inhibiting reactive oxygen species overproduction via the PI3K-Akt pathway

Clinical evidence indicates that insulin therapy improves implant survival rates in diabetic patients; however, the mechanisms responsible for this effect are unknown. Here, we test if insulin exerts anti-oxidative effects, thereby improving diabetes-associated impaired osteoblast behavior on titanium implants. To test this hypothesis, we cultured primary rabbit osteoblasts in the presence of titanium implants and studied the impact of treatment with normal serum (NS), diabetic serum (DS), DS + insulin, DS + tempol (a superoxide dismutase mimetic), DS + insulin + tempol, and DS + insulin + wortmannin. We analyzed cell function, apoptosis, and reactive oxygen species (ROS) production in osteoblasts following the various treatments. Treatment with DS induced osteoblast dysfunction, evidenced by impaired cell attachment and morphology, decreased cell proliferation and ALP activity, and decreased expression of osteogenesis-related genes. We also observed a significant increase in apoptosis. Importantly, treatment with DS resulted in increased production of ROS in osteoblasts. In contrast, treatment with insulin inhibited ROS production, alleviated cell dysfunction, and decreased apoptosis of osteoblasts on the implants. Scavenging ROS with tempol also attenuated cell dysfunction. Compared to insulin treatment alone, the combination of insulin and tempol failed to further improve osteoblast functional recovery. Moreover, the anti-oxidative and pro-osteogenic effects afforded by insulin were almost completely abolished by the phosphatidylinositol 3-kinase (PI3K) inhibitor wortmannin. These results demonstrate, for the first time, that insulin treatment alleviates the impaired osteogenesis of titanium implants under diabetic conditions by inhibiting ROS overproduction via a PI3K/Akt-dependent mechanism. Both the anti-oxidative and metabolic properties of insulin should make it a viable therapeutic option to combat diabetic implant failure.

Correction of Malpositioned Implants through Periodontal Surgery and Prosthetic Rehabilitation Using Angled Abutment

When dental implants are malpositioned in relation to the adjacent teeth and alveolar bone or in an excessive buccal or lingual position, the final prosthesis rehabilitation impairs the peri-implant health of the gingival tissues and the aesthetics of the patient. Thus, the purpose of this case was to report and discuss a multidisciplinary protocol for the treatment of a compromised maxillary tooth in a patient with an abscess in his right central incisor due to an excessive buccal implant position. The patient presented with an implant-supported provisional restoration on his right maxillary central incisor and a traumatic injury in his left central incisor. The treatment protocol consisted in (i) abutment substitution to compensate the incorrect angulation of the implant, (ii) clinical crown lengthening, (iii) atraumatic extraction of the left central incisor, and (iv) immediate implant placement. Finally, (v) a custom abutment was fabricated to obtain a harmonious gingival contour around the prosthetic crown. In conclusion, when implants are incorrectly positioned in relation to the adjacent teeth, associated with soft-tissue defects, the challenge to create a harmonious mucogingival contours may be achieved with an interdisciplinary approach and with the placement of an appropriate custom abutment.