Contribution of the PDL to Osteotomy Repair and Implant Osseointegration

Our objective was to clarify the fate of the periodontal ligament (PDL) retained in the socket after tooth extraction, then determine if this tissue contributed to the osseointegration of "immediate" implants placed in these fresh extraction sockets. Mice underwent maxillary first molar extraction, the residual PDL was removed by an osteotomy, and titanium implants were placed. The osteotomy was created in such a way that the palatal surface was devoid of PDL remnants while the buccal, mesial, and distal surfaces retained PDL fibers. At multiple time points after surgery, tissues were analyzed using a battery of molecular, cellular, and histomorphometrical assays. We found that PDL remnants mineralized and directly contributed to new bone formation in the extraction site. Compared with regions of an extraction site where the PDL was removed by osteotomy, regions that retained PDL fibers had produced significantly more new bone. Around immediate implants, the retained PDL remnants directly contributed to new bone formation and osseointegration. Thus, we conclude that PDL remnants are inherently osteogenic, and if the tissue is healthy, it is reasonable to conclude that curetting out an extraction socket prior to immediate implant placement should be avoided. This recommendation aligns with contemporary trends toward minimally invasive surgical manipulations of the extraction socket prior to immediate implant placement.

Synthesis and characterization of organosoluble, transparent, and hydrophobic fluorinated polyimides derived from 3,3′-diisopropyl-4,4′-diaminodiphenyl-4′′-trifluoromethyltoluene

A novel aromatic fluorinated diamine monomer, 3,3′-diisopropyl-4,4′-diaminodiphenyl-4′′-trifluoromethyltoluene, was synthesized by coupling of 2-isopropylaniline and 4-(trifluoromethyl)benzaldehyde and its structure was confirmed by Fourier transform infrared spectroscopy, nuclear magnetic resonance, elemental analysis, and mass spectrometry, and then used to prepare a series of fluorinated polyimides (FPIs) by polycondensation reaction with various commercial dianhydrides via conventional one-step method. The obtained FPIs present excellent solubility in most organic solvents and enough to cast into tough and flexible films. All the FPI films show good optical transparency and light color with the cutoff wavelengths in range of 307–362 nm and the average transmittance above 86%. These polymer films also exhibit high glass transition temperature in range of 261–331°C and thermal stability with 10% weigh loss above 463°C under nitrogen atmosphere. Furthermore, they exhibit outstanding mechanical properties with tensile strengths of 65.9–94.3 MPa, elongation at break of 11.4–13.8%, Young’s modulus of 1.6–1.9 GPa, and low dielectric constants in range of 2.75–3.10 at 1 MHz as well as prominent hydrophobicity with the contact angle in the range of 87.3–93.9°.

The revascularization and follicular survival of mouse ovarian grafts treated with FSH during cryopreservation by vitrification

BACKGROUND

Ovarian cryopreservation by vitrification is a very effective pathway for the preservation of female fertility during radiotherapy and chemotherapy. However, damage of follicles was triggered by cryo-injure during the process of ovarian vitrification and ischemia/reperfusion during the process of ovarian transplantation. Appropriate FSH play important roles in anti-apoptosis and neoangiogenesis during ovarian follicle development.

OBJECTIVE

Therefore, the purpose of this study was to investigate the effect of FSH on the revascularization and follicular survival of vitrified-warmed ovarian grafts.

MATERIALS AND TMETHODS

Four-week-old C57BL/6J mice with diestrus were used and the ovaries were randomized into the following three groups: fresh control group (FCG), vitrified/warmed group (VCG) and vitrified/warmed group treated with 0.3 IU/mL FSH (FSH-VG) during ovarian vitrification. After warming, the ovaries of the three groups were allotransplanted into the renal capsule of receptor mice. Assessment of follicular quantity was performed by histological analysis. The angiogenesis factors, CD31 and MMP-2, and cell survival factors, PCNA, EdU and survivin were examined by immunohistochemistry and western blot analysis. Angiogenesis was detected by vascular perfusion with the fluorescent dye 2MD-FITC-Dextran.

RESULTS

The expression of CD31and MMP-2 were not significantly different in either VCG or FSH-VG compared with FCG, but when the ovaries were transplanted 48 hours later, the expression levels of CD31 and MMP-2 were lower for VCG than FCG (P < 0.05) and FSH-VG was not significantly different from FCG. Before transplantation, the expression levels of PCNA and survivin were lower for VCG and FSH-VG than FCG (p < 0.05), but FSH-VG was higher than VCG (p < 0.05). After 48 h of ovarian transplantation, the expression of survivin was lower for VCG than FCG (P < 0.05), but FSH-VG was not significantly different from FCG. In addition, these data were further supported by the results from detecting the 2MD-FITC-Dextran and EdU.

CONCLUSION

Taken together, supplementation with 0.3 IU/mL FSH during ovarian cryopreservation by vitrification increased the revascularization and follicular survival for mouse ovarian grafts through the up-regulated expression of angiogenesis and ovarian survival factors.