Fecal microbiota transplantation(FMT)of human fecal samples into germ-free(GF)mice is useful for establishing causal relationships between the gut microbiota and human phenotypes.However,due to the intrinsic differences between human and mouse intestines and the different diets of the two organisms,it may not be possible to replicate human phenotypes in mice through FMT;similarly,treatments that are effective in mouse models may not be effective in humans.In this study,we aimed to identify human gut microbes that undergo significant and consistent changes(i.e.,in relative abundances)after transplantation into GF mice in multiple experimental settings.We collected 16S rDNA-seq data from four published studies and analyzed the gut microbiota pro-files from 1713 human-mouse pairs.Strikingly,on average,we found that only 47％of the human gut microbes could be re-established in mice at the species level,among which more than 1/3 under-went significant changes(referred to as"variable taxa").Most of the human gut microbes that underwent significant changes were consistent across multiple human-mouse pairs and experimen-tal settings.Consequently,about 1/3 of human samples changed their enterotypes,i.e.,significant changes in their leading species after FMT.Mice fed with a controlled diet showed a lower enter-otype change rate(23.5％)than those fed with a noncontrolled diet(49.0％),suggesting a possible solution for rescue.Most of the variable taxa have been reported to be implicated in human dis-eases,with some recognized as the causative species.Our results highlight the challenges of using a mouse model to replicate human gut microbiota-associated phenotypes,provide useful informa-tion for researchers using mice in gut microbiota studies,and call for additional validations after FMT.An online database named FMT-DB is publicly available at http://fmt2mice.humangut.info/#/.

Objective:To study the bacterial microleakage at the interface between dental implant and abutment in rats.Methods:Under aseptic conditions, suspension of 0.25 μl of Porphyromonas gingivalis (Pg) (10 9 CFU/ml) was added into the customized implant. After the abutment was connected, the suspension was cultured in an Ep (eppendorf) tube containing 1 ml brain heart infusion (BHI) culture medium. After 7 days and 14 days, the liquid in the Ep tube was taken and inoculated, and the growth of bacteria was observed. Six male SD rats with 12 implants were divided into experimental group (4 implants), negative control group (4 implants) and blank control group (4 implants). All 6 rats had two implants implanted in their bilateral upper jaws. During the second operation, suspension of 0.25 μl Pg (10 9 CFU/ml) was added to the inner part of the implant of the experimental group, culture solution of 0.25 μl was added to the control group and nothing was added to the blank control group. The amount of Pg and total bacteria in each group were evaluated by quantitative real-time PCR (qPCR). The inflammatory cell infiltrate in the peri-implant mucosa was evaluated histomorphometrically. Results:The in vitro model directly verified the presence of bacterial microleakage at implant-abutment interface (IAI), and the animal model confirmed the existence of microleakage through the infiltrate of inflammatory cells near the micro-gap in the experimental group indirectly. In vitro experiments found that Pg had penetrated from the implant within a week by observation and culture. In animal study, the presence of 10 2-10 4 Pg was detected in the experimental group and it was not detected in the negative control group and the blank control group. At the same time, under the light microscope, in the experimental group, there were inflammatory cells aggregation in the connective tissue around the micro-gap and the density of inflammatory cells gradually decreased from the micro-gap to coronal and the apical of the connective tissue, while there were only scattered inflammatory cells in the connective tissue around the blank control group and the negative control group. In the experimental group, inflammatory cells density in area of 0.25-0.50 mm, 0-0.25 mm coronal to the micro-gap and 0-0.25 mm, 0.25-0.50 mm apical to the mico-gap was respectively, 976 (655), 1 673 (1 245), 2 267 (819) and 895 (162) cells/mm 2,which was significantly more than the blank control group in the corresponding position [respectively 201 (180), 321 (351), 309 (236) and 218 (272) cells/mm 2] ( P<0.05). Conclusions:Pg in the dental implants of rats can be found in the microleakage through implant-abutment interface, and cause the soft tissue inflammation around the implant, and the inflammation has certain distribution characteristics.

Objective:To evaluate clinical effect of deproteinized bovine bone for delayed implantation after fenestration.Methods:This trial is a continuation of a prospective clinical trial. From May 2011 to February 2015 in Department of Implantology, School of Stomatology, The Fourth Military Medical University after planting division of 55 cases of maxillary teeth missing area of residual alveolar bone height ≤5 mm patients. There were 21 female and 34 male patients, their average age were (55.2±7.1) years. A total of 62 side fenestration of maxillary sinus floor lift, clinical and imaging examination, evaluation of implant retention rate, complications, peripheral soft tissue health and marginal bone resorption.Results:A total of 82 implants were followed up in 41 patients. The average follow-up time was (51.8±14.3) months (36-78 months). The follow-up rate of the maxillary sinus was 75.8% (47/62), the follow-up rate of the implant was 73.9% (82/111), and the implant survival rate was 98.8% (81/82). The bone resorption results at the implant margins were (0.64±0.63) mm (-0.28 mm, 1.47 mm) in the near and (0.49±0.73) mm (-0.51 mm, 1.21 mm) in the far, the improved hemorrhage index was 0.46±0.72, the improved plaque index was 0.60±0.87, and the keratinized mucosa width was (2.14±1.22) mm. The incidence rate of peri-implant mucositis was 28.4% (23/81) among 23 implants, and there was no complication of peri-implant inflammation.Conclusions:This study shows that under the condition of insufficient sinus ridge spacing in the maxillary posterior area, it is feasible to use bovine bone alone to remove protein for delayed implantation of maxillary sinus floor elevation by windowing, and the clinical effect is reliable.

Characterized by eminent mechanical properties, chemical stability and biosafety, polyetheretherketone (PEEK), as a brand-new type of biomedical material, has been applied in the field of stomatology. This review elaborates on basic behaviors and fabrication methods of PEEK and its composite, and their application in fixed dental prostheses (FDP) as frameworks as well as their adhesive properties. Meanwhile, this review also looks into the prospect of the integration of additive manufacturing in fabricating frameworks of PEEK and its composite in FDP.

Characterized by eminent mechanical properties, chemical stability and biosafety, polyetheretherketone (PEEK), as a brand?new type of biomedical material, has been applied in the field of stomatology. This review elaborates on basic behaviors and fabrication methods of PEEK and its composite, and their application in fixed dental prostheses (FDP) as frameworks as well as their adhesive properties. Meanwhile, this review also looks into the prospect of the integration of additive manufacturing in fabricating frameworks of PEEK and its composite in FDP.