Study on the Antibacterial Activity and Bone Inductivity of Nanosilver/PLGA-Coated TI-CU Implants.

Background: Implants are widely used in the field of orthopedics and dental sciences. Titanium (TI) and its alloys have become the most widely used implant materials, but implant-associated infection remains a common and serious complication after implant surgery. In addition, titanium exhibits biological inertness, which prevents implants and bone tissue from binding strongly and may cause implants to loosen and fall out. Therefore, preventing implant infection and improving their bone induction ability are important goals. Purpose: To study the antibacterial activity and bone induction ability of titanium-copper alloy implants coated with nanosilver/poly (lactic-co-glycolic acid) (NSPTICU) and provide a new approach for inhibiting implant-associated infection and promoting bone integration. Methods: We first examined the in vitro osteogenic ability of NSPTICU implants by studying the proliferation and differentiation of MC3T3-E1 cells. Furthermore, the ability of NSPTICU implants to induce osteogenic activity in SD rats was studied by micro-computed tomography (micro-CT), hematoxylin-eosin (HE) staining, masson staining, immunohistochemistry and van gieson (VG) staining. The antibacterial activity of NSPTICU in vitro was studied with gram-positive Staphylococcus aureus (Sa) and gram-negative Escherichia coli (E. coli) bacteria. Sa was used as the test bacterium, and the antibacterial ability of NSPTICU implanted in rats was studied by gross view specimen collection, bacterial colony counting, HE staining and Giemsa staining. Results: Alizarin red staining, alkaline phosphatase (ALP) staining, quantitative real-time polymerase chain reaction (qRT-PCR) and western blot analysis showed that NSPTICU promoted the osteogenic differentiation of MC3T3-E1 cells. The in vitro antimicrobial results showed that the NSPTICU implants exhibited better antibacterial properties. Animal experiments showed that NSPTICU can inhibit inflammation and promote the repair of bone defects. Conclusion: NSPTICU has excellent antibacterial and bone induction ability, and has broad application prospects in the treatment of bone defects related to orthopedics and dental sciences.

[Maxillofacial 3-dimensional morphological analysis for patients with Class III malocclusion and facial asymmetry].

PURPOSE: To investigate the skeletodental factors relating to the chin point deviation of facial asymmetry in skeletal Class III malocclusion patients using three-dimensional computed tomography. METHODS: Forty-one adult female patients with class III malocclusion, who underwent three-dimensional CT examination before orthodontics treatment, were assigned as group of symmetry or group of asymmetry according to the amount of chin point deviation from the facial midline. Midfacial and mandibular variables were measured. The data was analyzed with SPSS13.0 software package. RESULTS: Patients in the group of asymmetry showed higher positions of the upper canine and first molar, shorter ramus height, more superior positioning of gonion on the deviated side, more mesial and frontal inclination of the ramus, medial and frontal positioning of gonion on the opposite side than the group of symmetry. Menton deviation correlated significantly with the difference of ramus height between the 2 sides ramus, ramus height in the deviated side and other skeletodental factors. CONCLUSIONS: Facial asymmetry in Class III patients is due to the overgrowth,frontal and mesial inclination of the ramus in the opposite side.

[Influence of chin prominence on anterior-posterior lip positions of facial profile].

PURPOSE: To determine the influence of chin prominence on preferred lip position in profile. METHODS: The average profile was constructed from the profile of a young Chinese man who has typical Chinese facial profile. Changes in chin position were established by altering the antero-posterior position by protruding or retruding the chin in increments of 5 degrees and 10 degrees from the average profile. The lips were then protruded or retruded in 1mm increments from the average profile and 9 silhouettes were arranged respectively. One hundred and eighty college students were asked to rate the top three most favored, well-balanced profiles.SPSS13.0 software package was used to compare the differences in the scores between the top three most favored profiles and the other profiles. RESULTS: Slightly retruded lip positions were preferred for the average profile.The scores in top three profiles were significantly larger than the other profiles(P<0.05);The raters tended to prefer more retruded lip positions as the facial convexity decreased and more protruded lip positions as the facial convexity increased. CONCLUSIONS: The chin position does significantly impact preferred lip position and different esthetic standards should be applied to the various profiles encountered in clinical practice.The results might be helpful in decisions between extraction and nonextraction treatment in borderline cases.