In Vitro Cytokine Expression and In Vivo Healing and Inflammatory Response to a Collagen-Coated Synthetic Bone Filler

Long-term results of autologous periosteum-derived micro-grafts with poly(lactic-go-glycolic acid) in sinus lift augmentation surgeries: A 7-years follow-up observational study

INTRODUCTION AND IMPORTANCE

The study aimed to present the long-term results of autologous and homologous micrografts for bone regeneration aimed at positioning dental implants after sinus lift augmentation surgeries, by combining autologous Rigenera® micrografts with poly(lactic-go-glycolic acid).

CASE PRESENTATION

A total of 5 patients (2 males and 3 females) from 36 to 71 years were involved in the observational study. All the patients showed a good health status system (ASA1 and 2), according to their clinical history with neither system diseases, nor under medication able to interfere with osseointegration.

CLINICAL DISCUSSION

The radiographic evaluations, after the implant placement and during the continuous follow-up upto 7 years, were carried out through periapical endoral x-rays. The survival and implant success rate was 100 %. Histological analyses were performed after 3 and 7 months after the surgical procedure.

CONCLUSION

No adverse events have been observed that can be traced back to the use of autologous micrografts with poly(lactic-go-glycolic acid), showing safety and predictable results even in long term.

Biologically Relevant In Vitro 3D-Model to Study Bone Regeneration Potential of Human Adipose Stem Cells

Standard cell cultures may not predict the proliferation and differentiation potential of human mesenchymal stromal cells (MSCs) after seeding on a scaffold and implanting this construct in a bone defect. We aimed to develop a more biologically relevant in vitro 3D-model for preclinical studies on the bone regeneration potential of MSCs. Human adipose tissue-derived mesenchymal stromal cells (hASCs; five donors) were seeded on biphasic calcium phosphate (BCP) granules and cultured under hypoxia (1% O2) for 14 days with pro-inflammatory TNFα, IL4, IL6, and IL17F (10 mg/mL each) added during the first three days, simulating the early stages of repair (bone construct model). Alternatively, hASCs were cultured on plastic, under 20% O2 and without cytokines for 14 days (standard cell culture). After two days, the bone construct model decreased total DNA (3.9-fold), COL1 (9.8-fold), and RUNX2 expression (19.6-fold) and metabolic activity (4.6-fold), but increased VEGF165 expression (38.6-fold) in hASCs compared to standard cultures. After seven days, the bone construct model decreased RUNX2 expression (64-fold) and metabolic activity (2.3-fold), but increased VEGF165 (54.5-fold) and KI67 expression (5.7-fold) in hASCs compared to standard cultures. The effect of the bone construct model on hASC proliferation and metabolic activity could be largely mimicked by culturing on BCP alone (20% O2, no cytokines). The effect of the bone construct model on VEGF165 expression could be mimicked by culturing hASCs under hypoxia alone (plastic, no cytokines). In conclusion, we developed a new, biologically relevant in vitro 3D-model to study the bone regeneration potential of MSCs. Our model is likely more suitable for the screening of novel factors to enhance bone regeneration than standard cell cultures.

Detection of peri-implant inflammation by the use of a matrix metalloproteinase-8 chair-side test

BACKGROUND

Active matrix metalloproteinase-8 (MMP-8) enzymes are associated with inflammation and the degradation of implant-supporting tissues. A high concentration of these enzymes in the peri-implant sulcular fluid (PISF) has been associated with a pathological condition. The aim of the present study was to evaluate the ability of a chair-side MMP-8 test to individuate pathological peri-implant site. The working hypothesis is that positive response to MMP-8 test corresponds to pathological values of periodontal indexes. A secondary working hypothesis is that PISF sampling method influences the test accuracy.

METHODS

Fifty implants from 50 patients were evaluated during scheduled follow-up appointments in a clinical setting using the MMP-8 chair-side test and periodontal indices (probing depth, bleeding on probing, plaque index and peri-implant inflammation index). Two methods of PISF sampling were tested.

RESULTS

The MMP-8 test demonstrated significant diagnostic capacity and good sensitivity and accuracy regarding indices of bleeding on probing, plaque index, and peri-implant inflammation index but fair agreement.

CONCLUSIONS

Further studies should be performed to better define the interpretation of the MMP-8 chair-test results and their correlation to peri-implant indexes.

[Effect of human tooth bone graft materials on proliferation and differentiation of mice mononuclear macrophage RAW264.7]

Objective

To investigate the effect of human tooth bone graft materials on the proliferation, differentiation, and morphology of macrophages, and to understand the biocompatibility and cytotoxicity of human tooth bone graft materials.

Methods

Fresh human teeth were collected to prepare human tooth bone graft materials, the adhesion of mouse mononuclear macrophages RAW264.7 to human bone graft materials was observed under confocal microscopy. Scanning electron microscopy was used to observe the morphology of human tooth bone graft materials, OSTEONⅡ synthetic highly resorbable bone grafting materials, and untreated tooth powder (dental particles without preparation reagents). Different components of the extract were prepared in 4 groups: group A (DMEM medium containing 10% fetal bovine serum), group B (human tooth bone graft materials), group C (OSTEONⅡ synthetic highly resorbable bone grafting materials), group D (untreated tooth powder without preparation reagents). The 4 groups of extracts were co-cultured with the cells, and the cytotoxicity was qualitatively determined by observing the cell morphological changes by inverted microscope. The cell proliferation and differentiation results and cell relative proliferation rate were determined by MTT method to quantitatively determine cytotoxicity. The cell viability was detected by trypanosoma blue staining, and tumor necrosis factor α (TNF-α ) and interleukin 6 (IL-6) expressions were detected by ELISA.

Results

Scanning electron microscopy showed that the surface of the human tooth bone graft material and the OSTEONⅡ synthetic highly resorbable bone grafting materials had a uniform pore structure, while the untreated tooth particle collagen fiber structure and the demineralized dentin layer collapsed without specific structure. Confocal microscopy showed that the cells grew well on human tooth bone graft materials. After co-culture with the extract, the morphology and quantity of cells in groups A, B, and C were normal, and the toxic reaction grades were all grade 0, while group D was grade 3 reaction. MTT test showed that the cytotoxicity of groups B and C was grade 0 or 1 at each time point, indicating that the materials were qualified. The cytotoxicity was grade 2 in group D at 1 day after culture, and was grade 4 at 3, 5, and 7 days. Combined with cell morphology analysis, the materials were unqualified. The trypanosoma blue staining showed that the number of cells in groups A, B, and C was significantly higher than that in group D at each time point ( P<0.05), but no significant difference was found among groups A, B, and C ( P<0.05). ELISA test showed that the levels of TNF-α and IL-6 in groups A, B, and C were significantly lower than those in group D ( P<0.05), but no significant difference was found among groups A, B, and C ( P<0.05).

Conclusion

The human tooth bone graft materials is co-cultured with mice mononuclear macrophages without cytotoxicity. The extract has no significant effect on cell proliferation and differentiation, does not increase the expression of inflammatory factors, has good biocompatibility, and is expected to be used for clinical bone defect repair.

Maxillary Sinus Lift Using Autologous Periosteal Micrografts: A New Regenerative Approach and a Case Report of a 3-Year Follow-Up

This case report discusses about an innovative bone regeneration method that involves the use of autologous periosteal micrografts, which were used for a maxillary sinus floor lift in a 52-year-old female patient. This method allows for harvesting of a graft that is to be seeded on a PLGA scaffold and involves collection of a very little amount of palatal periosteal tissue in the same surgical site after elevation of a flap and disaggregation of it by using a Rigenera® filter. Histological samples collected at the time of implant installation demonstrate a good degree of bone regeneration. The clinical and radiographic outcomes at the 3-year follow-up visit showed an adequate stability of hard and soft tissues around the implants. This report demonstrates the possibility to obtain a sufficient quality and quantity of bone with a progenitor cell-based micrograft and in turn make the site appropriate for an implant-supported rehabilitation procedure, with stable results over a period of two years.

Long-Term Effects of Acute Myeloid Leukemia Treatment on the Oral System in a Pediatric Patient

Introduction:

Acute Myeloid Leukemia (AML) in pediatric patients is a serious disease, although, for the subgroup of patients who receive proper treatment, a long-term survival rate above 50% is typical. The cycles of chemo- and radiotherapy used to treat AML can impair dental development.

Case Report:

Herein, we describe the oral condition of a 25-year-old male patient treated for AML with chemo- and radiotherapy from 5 to 7 years of age; his AML has remained in remission for the past 18 years. He had lost only one permanent tooth, but the remaining teeth demonstrated serious deformations and radicular hypoplasia. Two teeth required immediate extraction and subsequent replacement by implant-supported crowns. We found that the decayed, missing, filled teeth (DMFT) index was not representative of the real oral condition. Here, we report the full case and provide a brief review of the literature.

Conclusion:

Antitumor treatment of pediatric leukemia can induce total impairment of dental development and function. These adverse effects may become clinically evident many years after the resolution of cancer, and can be significantly detrimental to the patient’s quality of life.