Calcium phosphate cement with minocycline hydrochloride-loaded gelatine microspheres for peri-implantitis treatment.

OBJECTIVES: This study aimed to fabricate an antibacterial calcium phosphate cement (CPC) with minocycline hydrochloride (MINO)-loaded gelatine microspheres (GMs) as a local drug delivery system for the treatment of peri­implantitis. METHODS: CPC/GMs(MINO), incorporating MINO-loaded GMs into CPC, was developed and characterised using scanning electron microscopy (SEM), X-ray diffraction (XRD), and drug release profiling. The antibacterial activity against Porphyromonas gingivalis and Fusobacterium nucleatum was evaluated. Bone mesenchymal stem cells (BMSCs) were cultured in the extracts of the developed cements to evaluate osteoinductivity in vitro. Furthermore, a rabbit femoral model was established to evaluate osteogenic ability in vivo. RESULTS: SEM and XRD confirmed the porous structure and chemical stability of CPC/GMs(MINO). The release profile showed a sustained release of MINO from CPC/GMs(MINO), reaching an equilibrium state on the 14th day with a cumulative release ratio of approximately 84%. For antibacterial assays, the inhibition zone of CPC/GMs(MINO) was 3.67 ± 0.31 cm for P. gingivalis and 7.47 ± 0.50 cm for F. nucleatum. Most bacteria seeded on CPC/GMs(MINO) died after 24 h of culture. In addition, CPC/GMs(MINO) significantly enhanced alkaline phosphatase activity, osteogenic gene expression, and BMSC mineralisation compared with CPC/GMs and the control group (P < 0.05). The in vivo results showed that CPC/GMs(MINO) possessed a higher quality and quantity of bone formation and maturation than CPC/GMs and CPC. CONCLUSIONS: CPC/GMs(MINO) showed excellent antibacterial activity against pathogens associated with peri­implantitis and demonstrated good osteoinductivity and osteogenic ability. CLINICAL SIGNIFICANCE: Peri-implantitis is among the most common and challenging biological complications associated with dental implants. In this study, MINO-loaded GMs were incorporated into CPC, which endowed the composite cement with excellent antibacterial and osteogenic abilities, demonstrating its potential as a bone graft substitute for treating peri­implantitis.

Naringin Release from a Nano-Hydroxyapatite/Collagen Scaffold Promotes Osteogenesis and Bone Tissue Reconstruction.

Bone fractures and defects are a major health issue and have reportedly affected over 455 million individuals globally to date. Bone tissue engineering has gained great success in bone defect repair and bone reconstruction based on the use of nano-hydroxyapatite (nHA) or collagen (COL). Both nHA and COL exhibit osteogenic induction capacity to support bone tissue regeneration; however, the former suffers from poor flexibility and the latter lacks mechanical strength. Biological scaffolds created by combining nHA and COL (nHA/COL) can overcome the drawbacks imposed by individual materials and, therefore, have become widely applied in tissue engineering. The composite scaffolds can further promote tissue reconstruction by allowing the loading of various growth factors. Naringin (NG) is a natural flavonoid. Its molecular weight is 580.53 Da, lower than that of many growth factors, and it causes minimal immune responses when being introduced in vivo. In addition, naringin is safe, non-toxic, inexpensive to produce, and has superior bio-properties. In this study, we introduced NG into a nHA/COL scaffold (NG/nHA/COL) and exploited the potentials of the NG/nHA/COL scaffold in enhancing bone tissue regeneration. NG/nHA/COL scaffolds were fabricated by firstly combining nHA and collagen at different compositional ratios, followed by NG encapsulation. NG release tests showed that the scaffold with a nHA/COL mass ratio of 7:3 exhibited the optimal property. The in vitro cell study showed the desirable biocompatibility of the NG/nHA/COL scaffold, and its effective promotion for the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), as proved by an increased alkaline phosphatase (ALP) activity, the formation of more calcium nodules, and a higher expression of osteogenic-related genes involving Osteocalcin (OCN), BMP-2, and Osteopontin (OPN), compared with the control and nHA/COL groups. When administered into rats with skull defects, the NG/nHA/COL scaffold significantly promoted the reconstruction of bone tissues and the early repair of skull defects, indicating the great potential of NG/nHA/COL scaffolds in bone tissue engineering.

Osteogenic growth peptide (OGP)-loaded amphiphilic peptide (NapFFY) supramolecular hydrogel promotes osteogenesis and bone tissue reconstruction.

Efficient bone reconstruction after bone injury remains a great challenge. Injectable supramolecular hydrogels based on amphiphilic peptide have been widely used due to their good biocompatability, non-immunogenicity, and manipulable physicochemical properties by sequence design. Herein, we used a well-studied hydrogelator, NapFFY, to coassemble with osteogenic growth peptide (OGP) to prepare a supramolecular hydrogel, NapFFY-OGP. Both in vitro and in vivo studies demonstrate that OGP was ideally synchronously, and continuously released from the hydrogel to effectively promote the regeneration and reconstruction of skull bone defects. More specifically, after the embedding the rat skull defect area with NapFFY-OGP hydrogels, a bone regeneration rate of 37.54% bone volume fraction (BV/TV) was achieved compared to that of NapFFY hydrogel group (25.09%). NapFFY-OGP hydrogel shows great promise in the clinic repair of bone defects in the future.

Correlation analysis of temporomandibular joint changes after maxillary protraction in adolescent patients / 口腔疾病防治

Objective @#To study the effect of anterior traction on the temporomandibular joint in adolescent patients with skeletal Class Ⅲ malocclusion.@*Methods@#Twenty-nine patients with early permanent dentition with skeletal class Ⅲ malocclusions were measured by cephalometry and a coordinate system before and after maxillary protraction. The correlation between dentofacial structures and the temporomandibular joint was analyzed. @*Results @# After maxillary protraction, cephalometric measurements showed that the dentofacial structure changed significantly; ANB increased by 3.97° ± 2.32° (P<0.001); U1-SN increased by 4.97° ± 5.51° (P<0.001); L1-MP decreased by 1.26° ± 1.41° (P = 0.008); and MP-SN increased by 1.02° ± 3.90° (P = 0.003). The coordinate system measurement showed that the S-Fpx was decreased by 0.16 ± 1.52 mm (P = 0.041), the S-Ciy distance was significantly decreased by 0.09 ± 2.03 mm (P = 0.028), and there was no significant change in the temporomandibular joint spaces (A, P, and C) (P>0.05). Correlation analysis showed a moderate negative correlation between the posterior margin of the temporomandibular joint fossa and U1-SN (r = -0.427, P = 0.042). There was a moderate positive correlation between the leading edge of the condyle and ANB (r = 0.425, P = 0.043); there was no correlation between the joint space and dentofacial changes. @* Conclusion@#After treatment with maxillary protraction for adolescent skeletal class Ⅲ malocclusion, maxillary protraction had some effect on changes in the temporomandibular joint fossa and condyle and had no effect on the joint space.

Effects of Rhein-8-O-ß-D-glucopyranoside on the Biofilm Formation of Streptococcus mutans.

Dental caries is the most frequent biofilm-related human infectious disease in the oral cavity. Streptococcus mutans is one of the primary etiological agents of dental caries. The aim of our study was to investigate the effects of rhein-8-O-ß-D-glucopyranoside (Rg) on the development of S. mutans biofilms. Growth curves were generated, and biofilm oxygen sensitivity was detected after Rg treatment. The expression levels of luxS, brpA, ffh, recA, nth, and smx were analyzed by real-time PCR. The trypan blue exclusion assay was used to measure the effect of Rg on monocyte viability. The results showed that Rg could significantly inhibit the growth of S. mutans and suppress the biofilm formation of S. mutans in a concentration-dependent manner. In Rg-treated biofilms, the expression levels of luxS, brpA, ffh, recA, nth, and smx were all decreased. Our results further showed that Rg was nontoxic, as Rg did not affect monocyte viability or lactate dehydrogenase activity in the exposed cells. These results suggested that Rg inhibited the biofilm formation of S. mutans, and the decrease in luxS, brpA, ffh, recA, nth, and smx expression might contribute to the antibacterial effects of Rg.

[Longitudinal survey and analysis among Chengdu residents on cognition and acceptance of implant dentures].

OBJECTIVE: This study aims to survey the cognition and acceptance of implant dentures among Chengdu residents in 2005 and 2013 and to comparatively analyze the differences and influencing factors. METHODS: A questionnaire was designed for this study. Its main content included basic demographics of respondents (gender, age, cultural level, and income level), cognition level of implant dentures (concept and main characteristics of implant dentures), main concern of respondents regarding implant dentures and medical institutions, and acceptance level of the price of implant dentures, among others. The sampling survey was carried out among Chengdu residents in 2005 and 2013 using the designed questionnaire. The results were then statistically analyzed. RESULTS: Up to 908 valid questionnaires in 2005 and 905 valid questionnaires in 2013 were obtained. The level of cognition of implant dentures was higher in 2013 than in 2005, and the correlation between cognition and cultural level and that between cognition and income level were both positive. However, the correlation between cognition and age was negative. The success rate for implant dentures and medical treatment technology of medical institutions were the factors that the respondents were mainly concerned with. The main methods for disseminating information on implant dentures were the internet, television, newspapers, magazines, and introduction by friends. CONCLUSION: With the development of the society's economy and the improvement of culture and income level of Chengdu residents, the cognition and acceptance level of implant dentures have gradualy increased. Meanwhile, health education and medical technology still need to be strengthened.

[Hard and soft tissue changes following the treatment of Class II division 1 malocclusion using twin-block appliance].

OBJECTIVE: To investigate the hard and soft tissue changes following the treatment of Class II division 1 malocclusion using Twin-block appliance. METHODS: 50 Class II division 1 malocclusion subjects whose handwrist radiographs were in FG-G stage were selected. One group (27 patients) was treated with Twin-block appliance, the other group (23 patients) was observed without treatment The acquired data of cephalometric of two groups were analyzed statistically with SPSS 11.0. RESULTS: Soft tissue changes, Ls-E, Li-E, U1-Stms, Stms-Stmi, NsLs-FH, LsNsLi, LsNsPg', the angle of H decreased. Sn-Stms, Stmi-Me', Ns-Me', Sn-Me', NsLi-FH, NsPg'-FH, A'Ls-FH, B'Li-FH, LiB' Pg', CmSnLs, GSnPg', the angle of Z increased, there was statistically significant difference (P < 0.05). Hard tissue changes, SNB, L1-NB, IMPA increased, ANB, U1-SN, U1-NA, FMIA decreased, there was statistically significant difference (P < 0.05). CONCLUSION: Sagittal relationship between upper- and lower-jaws is effectively improved after orthopedics with Twin-block appliance. Lower face height increases. Soft tissue profile tends to be straight-styled.

[Soft tissue changes following the treatment of Class II division 1 malocclusion using Headgear-activator appliance].

PURPOSE: To investigate the soft tissue changes following the treatment of Class II division 1 malocclusion using Headgear-activator appliance. METHODS: Fifty Class II division 1 malocclusion subjects who were at peak high velocity on the growth curve were divided into two groups. Standardized lateral cephalogram was taken for each patient in the two groups before and after treatment. SPSS11.0 software package was used to calculate the mean and standard deviation, matched t-test was used to evaluate the changes of the soft tissues. RESULTS: The angle of CmSnLs,LiB'Pg' and Z increased, the angle of H, LsNsLi and LsNsPg' decreased, there was statistically significant difference between the two groups. CONCLUSIONS: Using Headgear-activator appliances, soft tissue profile is effectively improved. Soft tissue chin is moved forward obviously. Lip protrusion is decreased.

[Bone histomorphometry study in agglutination of femoral condyle of dog after being compressed].

OBJECTIVE: This study simulated clinical implant surgery using squeeze technique by establishing a rational animal model. To measure the morphologic parameters in order to observe the agglutination of the cancellous bone after being compressed. The study wanted to get some favourable support of implant squeeze technique in bone healing and obtaining primary stabilities of implants, so as to provide some reasonable and valid guidance in the application and improvement of implant squeeze technique. METHODS: The cancellous bone in condyles of femur of dog had been chosen as the experimental position, prepared the implant holes using squeeze technique according to different compressing extent (0, 0.6, 1.2, 2.0 mm), and then inserted the corresponding implants into them. After different healing periods (1, 2, 4, 12 weeks), the mongrel dogs were sacrificed and the hard tissue slices were made and then the morphologic parameters were measured. RESULTS: The morphologic parameter of the bone tissue shows that after being compressed, the trabecular bone thickness was almost constant, while the trabecular bone number increased, and the trabecular bone spacing decreased, obviously in the 1-week and 2-week groups. The differences went down gradually along with the extend of healing time. CONCLUSION: The clinical implant surgery using squeeze technique can improve peri-implant bone density so it is good for obtaining primary stabilities of implants.

[Effect of early treatment with the Twin-block appliance].

OBJECTIVE: To evaluate the effectiveness of early treatment with the Twin-block appliance for the developing Class II division 1 malocclusion. METHODS: A Total of 30 children with Class II division 1 malocclusion, 18 (8 male, 10 female) out of which received treatment with the Twin-block appliance, the other 12 cases (6 male, 6 female) without treatment served as control group. Cephalometric data were collected at the start and the end of the study and statistical analysis were applied. RESULTS: Except the factor of growth, treatment with the Twin-block appliance resulted in reduction of ANB (1.55 degrees), overjet (5.46 mm) and correction of molar relationship (4.07 mm). These changes were due to the change of Pg/OLp, Co/OLp and mandibular length. The change of A/OLp was not significant. The skeletal effect contributing to the change on overjet and molar relation were 58% and 78% respectively. CONCLUSION: Early treatment with the Twin-block appliance was effective in reducing ANB angle, overjet and correction of molar relationship. The changes were mainly profit from the favorable skeletal change of mandible, especially from its length, while the effect on maxillary was not significant.