Susceptibility of different mouse strains to peri‐implantitis

Background and Objective

Peri‐implantitis (PI) is an inflammatory condition that affects the tissues surrounding dental implants. Although the pathogenesis of PI is not fully understood, evidence suggests that the etiology is multifactorial and may include a genetic component. The aim of this study was to investigate the role of genetics in the development of peri‐implantitis.

Material and Methods

Four‐week‐old C57BL/6J, C3H/HeJ and A/J male mice had their left maxillary molars extracted. Implants were placed in the healed extraction sockets. Upon osseointegration, ligatures were placed around the implant head for 1 or 4 weeks to induce PI. Micro‐computed tomography scanning was used to measure volumetric bone loss. Histological analyses were also performed to evaluate collagen organization and the presence of neutrophils and osteoclasts.

Results

Radiographically, comparing the ligature‐treated mice, C57BL/6J displayed the greatest amount of bone loss, followed by C3H/HeJ and A/J mice at 1 and 4 weeks. Histologically, at 1 week, C57BL/6J mice presented with the highest numbers of neutrophils and osteoclasts. At 4 weeks, C57BL/6J mice presented with the most active bone remodeling compared with the other two strains.

Conclusion

There were significant differences in the severity of peri‐implantitis among the different mouse strains, suggesting that the genetic framework can affect implant survival and success. Future work is needed to dissect the genetic contribution to the development of peri‐implantitis.     

Fertility and family planning in Jordan: results from the 1985 Jordan Husbands' Fertility Survey

The 1985 Jordan Husbands' Fertility Survey (JHFS) was designed to assess husbands' attitudes and behavior toward fertility and family planning. The 1985 JHFS was a follow-up survey to obtain data from husbands of women who were currently married in the 1983 Jordan Fertility and Family Health Survey (JFFHS). The results from the 1985 JHFS point to the usefulness of collecting fertility and family planning information from husbands. These findings showed that nearly 40 percent of the husbands do not believe in practicing contraception, and more than 50 percent of the husbands report that family size should be "up to God." How program officials address these issues will be important for the future success of the family planning program in Jordan.     

Local delivery of a CXCR3 antagonist decreases the progression of bone resorption induced by LPS injection in a murine model

Objectives

This experimental study was carried out to investigate the effects of locally delivered nanoparticles (AMG-487 NP) containing a CXCR3 antagonist in inhibiting the progression of LPS-induced inflammation, osteoclastic activity, and bone resorption on a murine model.

Materials and methods

Thirty, 7-week-old C57BL/6 J male mice were used. Inflammatory bone loss was induced by Porphyromonas gingivalis–lipopolysaccharide (P.g.-LPS) injections between the first and second maxillary molars, bilaterally, twice a week for 6 weeks (n?=?20). AMG-487 NP were incorporated into a liposome carrier and locally delivered on sites where P.g.-LPS was injected. Control mice (n?=?10) were injected with vehicle only. Experimental groups included (1) control, (2) LPS, and (3) LPS?+?NP. At the end of 1 and 6 weeks, mice were euthanized, maxillae harvested, fixed, and stored for further analysis.

Results

Volumetric bone loss analysis revealed, at 1 week, an increase in bone loss in the LPS group (47.9%) compared to control (27.4%) and LPS?+?NP (27.8%) groups. H&E staining demonstrated reduced inflammatory infiltrate in the LPS?+?NP group compared to LPS group. At 6 weeks, volumetric bone loss increased in all groups; however, treatment with the CXCR3 antagonist (LPS?+?NP) significantly reduced bone loss compared to the LPS group. CXCR3 antagonist treatment significantly reduced osteoclast numbers when compared to LPS group at 1 and 6 weeks.

Conclusions

This study showed that local delivery of a CXCR antagonist, via nanoparticles, in a bone resorption model, induced by LPS injection, was effective in reducing inflammation, osteoclast numbers, and bone loss.

Clinical relevance

CXCR3 blockade can be regarded as a novel target for therapeutic intervention of bone loss. It can be a safe and convenient method for periodontitis treatment or prevention applicable in clinical practice.

     

Early intervention of peri‐implantitis and periodontitis using a mouse model

1 Background

Peri‐implantitis is an inflammatory response to bacterial biofilm resulting in bone loss and can ultimately lead to implant failure. Because of the lack of predictable treatments available, a thorough understanding of peri‐implantitis's pathogenesis is essential. The objective of this study is to evaluate and compare the response of acute induced peri‐implantitis and periodontitis lesions after insult removal.

2 Methods

Implants were placed in one‐month‐old C57BL/6J male mice eight weeks post extraction of their left maxillary molars. Once osseointegrated, ligatures were placed around the implants and contralateral second molars of the experimental groups. Controls did not receive ligatures. After one week, half of the ligatures were removed, creating the ligature‐retained and ligature‐removed groups. Mice were sacrificed at two time points, 5 and 14 days, from ligature removal. The specimens were analyzed via micro‐computed tomography and histology.

3 Results

By 5 and 14 days after ligature removal, the periodontitis group experienced significant bone gain, whereas the peri‐implantitis group did not. Histologically, all implant groups exhibited higher levels of cellular infiltrate than any of the tooth groups. Osteoclast numbers increased in peri‐implantitis and periodontitis ligature‐retained groups and decreased following insult removal. Collagen was overall more disorganized in peri‐implantitis than periodontitis for all groups. Peri‐implantitis experimental groups revealed greater matrix metalloproteinase‐8 and NF‐kB levels than periodontitis.

4 Conclusions

Implants respond slower and less favorably to insult removal than teeth. Future research is needed to characterize detailed peri‐implantitis disease pathophysiology.