Impact of history of periodontitis on gene expression of bone-related factors in young patients

Immunomodulation in the Treatment of Periodontitis: Progress and Perspectives

Periodontitis is one of the most common dental diseases. Compared with healthy periodontal tissues, the immune microenvironment plays the key role in periodontitis by allowing the invasion of pathogens. It is possible that modulating the immune microenvironment can supplement traditional treatments and may even promote periodontal regeneration by using stem cells, bacteria, etc. New anti-inflammatory therapies can enhance the generation of a viable local immune microenvironment and promote cell homing and tissue formation, thereby achieving higher levels of immune regulation and tissue repair. We screened recent studies to summarize the advances of the immunomodulatory treatments for periodontitis in the aspects of drug therapy, microbial therapy, stem cell therapy, gene therapy and other therapies. In addition, we included the changes of immune cells and cytokines in the immune microenvironment of periodontitis in the section of drug therapy so as to make it clearer how the treatments took effects accordingly. In the future, more research needs to be done to improve immunotherapy methods and understand the risks and long-term efficacy of these methods in periodontitis.

Cellular and Molecular Dynamics during Early Oral Osseointegration: A Comprehensive Characterization in the Lewis Rat

OBJECTIVE

There is a need to improve the predictability of osseointegration in implant dentistry. Current literature uses a variety of in vivo titanium (Ti) implantation models to investigate failure modes and test new materials and surfaces. However, these models produce a variety of results, making comparison across studies difficult. The purpose of this study is to validate an oral osseointegration in the Lewis rat to provide a reproducible baseline to track the inflammatory response and healing of Ti implants.

METHODS

Ti screws (0.76 mm Ø × 2 mm length) were implanted into the maxillary diastema of 52 adult male Lewis rats. Peri-implant tissues were evaluated 2, 7, 14, and 30 days after implantation (n = 13). Seven of the 13 samples underwent microtomographic analysis, histology, histomorphometry, and immunohistochemistry to track healing parameters. The remaining six samples underwent quantitative polymerase chain reaction (qPCR) to evaluate gene expression of inflammation and bone remodeling markers over time.

RESULTS

This model achieved a 78.5% success rate. Successful implants had a bone to implant contact (BIC)% of 68.86 ± 3.15 at 30 days on average. Histologically, healing was similar to other rodent models: hematoma and acute inflammation at 2 days, initial bone formation at 7, advanced bone formation and remodeling at 14, and bone maturation at 30. qPCR indicated the highest expression of bone remodeling and inflammatory markers 2-7 days, before slowly declining to nonsurgery control levels at 14-30 days.

CONCLUSION

This model combines cost-effectiveness and simplicity of a rodent model, while maximizing BIC, making it an excellent candidate for evaluation of new surfaces.

Influence of photodynamic therapy on the periodontitis-induced bone resorption in rat

This study aimed to evaluate the effects of toluidine blue-mediated photodynamic therapy (TB-PDT) on the periodontitis-induced bone resorption in periodontitis in rats. Periodontal disease was induced by cotton ligature around the right second maxillary molar in 64 rats. After 4 weeks, the rats were randomly divided into four groups: sterile saline solution (control group); laser therapy (laser group); TB (100 μg/mL); TB plus laser (0.15 W/cm2) irradiation every other day for 240 s (PDT group). All rats were euthanized at 15 days postoperatively. Eight gingival tissue samples were collected from each group. The expressions of receptor activator of nuclear factor kappa-Β ligand (RANKL) and osteoprotegerin (OPG) in gingival tissue samples were detected by real-time quantitative polymerase chain reaction (RT-qPCR). The maxillae from the rest of the rats were taken for histological examination. In the PDT group, the analysis revealed less bone loss than in the control treatment (P < 0.05). No significant difference was found among the control group, TB group, and laser group (P > 0.05). Significantly higher and lower expressions of RANKL and OPG were revealed in the PDT group than that in control group, respectively (P < 0.01). When compared with the control group, the expression of RANKL was significantly reduced by 40.0% in periodontitis in rats treated with TB-PDT for 15 days (P < 0.01). The expression of OPG was increased in the PDT group with TB-PDT for 15 days, when compared with the control group (P < 0.05). TB-PDT treatment significantly reverses the abnormal expression of RANKL and OPG in periodontitis in rats.