BACKGROUND:The physicochemical properties and bioactivity of titanium surface will degrade with time because of the aging phenomenon,affecting the efficiency of implant-bone osseointegration.Therefore,the re-activation of the implant surface physicochencical properties and bioactivity is important.OBJECTIVE:To investigate the re-activation effect of ultraviolet rays on aging titanium surface.METHODS:Sand-blasted and acid-etched titanium discs were divided into three groups randomly:Group A was new titanium surface,Group B was stored in a sealed container for 4 weeks,Group C was treated with ultraviolet rays for 15 minutes after stored in the sealed container for 4 weeks.The surface roughness,elemental composition and surface energy of the titanium surface were examined by optical profilometer,X-ray photoelectron spectroscopy and contact angle measuring device,respectively.The bioactivity of the titanium surface was examined by cell culture experiments.MG63 osteoblast-like cells were cultured on the different titanium surfaces.After 30 minutes,1,2,4 hours of incubation,the cells were strained with Hoechst33342 fluorescence,and initial attachment of cells was evaluated by measuring the amount of cells attached to the titanium surface.The proliferation of cells was quantified in terms of cell density at 1 and 3 culture days using tetrazolium salt (MTS)-based colorimetry.RESULTS AND CONCLUSION:There was no obvious difference in the surface roughness of the three groups,and ultraviolet treatment did not change the surface morphology of titanium surface.X-ray photoelectron spectroscopy showed that the C element content of group A and group C was lower than that of group B (P ＜ 0.05),and the content of Ti,O,N elements was significantly higher than that of group B (P ＜ 0.05).No difference in the surface element composition between group A and group C was found.Both of the surface contact angles of group A and group C were Oo,but in group B,the value was 115°.The number of initially attached cells of group A and group C was significantly higher than that of group B after incubated 30 minutes,1,2 and 4 hours (P ＜ 0.05),and no difference between group A and group C was found.The proliferation of cells of group A and group C was significantly higher than that of group B after incubated 1 and 3 days (P ＜ 0.05),but no difference between group A and group C was found.In conclusion,ultraviolet rays show good effects on the re-activation of the aging titanium surface,which can reduce hydrocarbon contamination and recover the high surface energy to increase cell adhesion and proliferation.

Maxillary sinus membrane lesions have been broadly detected before implant surgery in the posterior maxilla region, resulting in uncertainty regarding maxillary sinus floor elevation surgery. In this context, we composed this commentary article based on the current literature and the clinical experience of our department. We discuss the common lesion types shown by CBCT including membrane pathological thickening, polyps/cystic lesions and air-liquid level in the sinus. Maxillary sinus floor elevation surgery can be conducted in patients with membrane thickening of 2-5 mm or with polyps/cysts of less than half of the sinus height (because the above symptoms have little influence on the outcome of surgery). Membrane thickening of more than 5 mm with ostium obstruction, antrochoanalpolyps, mucoceles and cysts of more than half of the sinus height should be carefully treated. Different treatments can be performed such as conducting elevation surgery while retaining the cyst, removing the cyst before surgery or removing the cyst during surgery based on the cyst type and size, inflammation, patency of the ostium, etc. Antibiotics-anti-inflammatory-aspiration, surgical debridement and oral lesions eliminations are generally used for treating post-operative sinusitis. Presurgical radiographic evaluation is the key to diagnosing and treating these membrane lesions. We highly advocate collaboration between our dentists and otolaryngologists on this issue.

OBJECTIVETo investigate the property of genipin-crosslinked silk fibroin(SF)/chitosan(CS) microspheres for slow releasing of bovine serum albumin (BSA).

METHODSBSA-loaded genipin-crosslinked SF/CS microspheres were prepared by emulsion cross-linking technique. The micropheres were observed for surface morphology and size distribution under scanning electron microscope (SEM), and X-ray diffractometry (XRD) and fourier transform infrared spectroscopy (FTIR) were used to analyze their structural characteristics. BCA method was used for determining the drug entrapment, loading rate and cumulative drug release in 21 days.

RESULTThe microspheres were spherical and showed a smooth surface with an average diameter of 7.84∓0.97 µm. The drug entrapment efficiency of the microspheres was (50.16∓4.32)% with a drug loading ratio of (1.25∓0.11)% and a cumulative release of the total drug of (75.2∓2.53)% in 21 days.

CONCLUSIONGenipin-crosslinked SF/CS microspheres have a high drug entrapment efficiency and possess good capacity of sustained drug release.

Chitosan ; chemistry ; Delayed-Action Preparations ; Emulsions ; Fibroins ; chemistry ; Iridoids ; chemistry ; Microscopy, Electron, Scanning ; Microspheres ; Particle Size ; Spectroscopy, Fourier Transform Infrared ; X-Ray Diffraction ; X-Rays

OBJECTIVETo study the influence of ultraviolet (UV) irradiation on physical and chemical properties of sandblasted and acid-etched (SA) titanium surface and their ability to adsorb human fibronectin (HFn).

METHODSSA and UV-SA surfaces were separately prepared. Surface morphology, roughness, elemental composition, wettability and HFn adsorption assay were performed for comparative analysis of these two surfaces.

RESULTSSA and UV-SA surface had a similar morphology with multi-holes, and average roughness. UV-SA surface had a lower C content (22.83%) and higher O content (51.20%) and presented hydrophilicity, while SA surface showed hydrophobicity. But the quantity of adsorbed HFn on SA surface at 10 min assay point [(0.41 ± 0.07) µg] was statistically higher than that on UV-SA surface [(0.26 ± 0.08) µg](P = 0.007).

CONCLUSIONSUV irradiation would not change the morphology and roughness of SA surface. However, it could reduce the hydrocarbon and increase the hydroxyl groups, and the absorption of HFn on UV-SA surface at 10 min assay point was statistically lower than that on SA surface. Therefore, the in-vitro bioactivity of UV-SA surface was not as good as that of SA surface.

Adsorption ; Fibronectins ; chemistry ; Humans ; Microscopy, Electron, Scanning ; Surface Properties ; Titanium ; Ultraviolet Rays ; Wettability

Objective : To compare the effect of the combined coronally advanced flap and connective tissue flap techniques with that of a guided tissue regeneration (GTR) technique on recovering the exposed root surface in a case of gingival retraction over the lower anterior teeth. Methods: A case of gingival recession (Miller Ⅲ type) over teeth 33-43 accompanied by hypersensitivity of the right lower teeth was treated using different techniques bilaterally. Teeth 42-43 were treated by a combined coronally advanced flap and connective tissue flap technique, while teeth 33-41 were treated by a GTR technique of a coronally advanced flap combined with an absorbable collagen membrane. Results : Teeth 42-43 exhibited ideal gingival recovering of the exposed root surface, with the disappearance of the hypersensitivity symptoms, during the follow-up visits at 3.5 months after surgery. However, the exposed root surface of teeth 33-41 exhibited no significant change in coverage at the same time points compared with the preoperative coverage. At 12 months after surgery, the recovered gingiva on the root surface of teeth 42-43 was stable. Conclusion The combined coronally advanced flap and connective tissue flap approach, which can achieve better coverage of the exposed root surface than the GTR technique, is a feasible and safe surgical method for treating cases with gingival recession. The GTR technique is not an effective method for treating cases with Miller Ⅲ type gingival recession over multiple teeth due to proximal attachment loss.

Objective: To evaluate the clinical effect of a digital whole-process surgical guide for immediate implantation in the molar area. Methods : Twenty-six patients with molar extraction plans were accepted for preoperative CBCT and model construction. Computer software was used to design the ideal three-dimensional position of the implant. The control group of 13 patients underwent immediate implantation with a free hand operation, whereas the experimental group of 13 patients underwent preparation and implant insertion under the guidance of a surgical guide. Bone grafting was performed, and a good initial stability was achieved. After 5 to 6 months, osseointegration was achieved, and the final restoration was delivered. After surgery, the accuracy of the three-dimensional position of the implants was measured, and at the 6 month return visit, the modified Plaque Index (mPLI), modified Sulcular Bleeding Index (mSBI) and probing depth (PD) were measured. Results : In the control group and experimental group, the vertical errors at the top of the implants were 1.246 ± 0.072 mm and 0.628 ± 0.046 mm (t = 26.078, P < 0.001), respectively, and the horizontal errors were 1.563 ± 0.086 mm and 0.546 ± 0.056 mm (t = 35.813, P < 0.001), respectively; and the vertical errors at the root of the implants were 1.352 ± 0.042 mm and 0.532 ± 0.030 mm (t = 57.021, P < 0.001), respectively, and the horizontal errors were 1.645 ± 0.076 mm and 0.625 ± 0.072 mm (t = 35.086, P < 0.001), respectively. For the experimental group, the mPLI value was 0.923 ± 0.760, the mSBI value was 0.846 ± 0.689, and the PD value was 3.460 ± 0.713 mm, which were significantly lower than those of the control group. For the control group, the mPLI value was 1.769 ± 0.927 (t = 2.546, P = 0.018), the mSBI value was 1.692 ± 0.947 (t = 22.605, P = 0.016) and the PD value was (4.579 ± 0.475) mm (t = 4.709, P < 0.001). Conclusion A digital surgical guide plate can increase the precision of immediate implantation and the peri-implant health in the molar area.

Objective : To evaluate the therapeutic effects of erbium-doped: yttrium aluminium garnet laser (Er: YAG laser) combined with guided bone regeneration (GBR) in the treatment of peri-implantitis bone defect. Methods : A total of 26 implants in 15 patients with peri-implantitis were selected and divided into experimental group (14 implants) and control group (12 implants) randomly. The experimental group was treated with Er: YAG laser combined with GBR, and the control group was treated with mechanical curettage with GBR. Clinical periodontal index test including plaque index (PI), sulcus bleeding index (SBI), probing depth (PD) and clinical attachment level (CAL) were checked at baseline, 3 months and 6 months. All the above data were statistically analyzed. Results : All of the clinical periodontal index were improved after surgery. SBI, PD and CAL of the experimental group was 0.8 ± 0.2 mm, 5.8 ± 0.8 mm, and 2.3 ± 0.7 mm, while they were 1.1 ± 0.2 mm, 6.2 ± 0.6 mm, and 3.6 ± 0.6 mm in the control group. The experimental group showed better results than the control group (P< 0.05), while PI showed no difference between the 2 groups (P> 0.05). Conclusion The combined application of Er: YAG laser and GBR in the treatment of bone defect in peri-implantitis has good clinical effects.

OBJECTIVE: This study aimed to evaluate the clinical effect of periodontal microscopic surgery on the augmentation of attached gingiva and determined the clinical principle on how to use minimally invasive surgery to improve the surgery success rate. METHODS: Twenty patients with insufficient attached gingiva around implants were selected. Periodontal microscopic surgery for free gingival graft was performed to increase the width of the attached gingiva around the implants. The survival state of the free gingiva was observed after surgery, and the width of the attached gingiva around the implants was recorded before and after surgery and 1 year after surgery. The shrinkage rate of the free gingival flap 1 year after surgery was analyzed to evaluate the stability of the flap. RESULTS: The flaps of the 20 cases all survived. One year after the operation, the width of the attached gingiva was (3.05±0.44) mm, which increased compared with that of preoperation (2.56±0.31) mm
and decreased compared with that of postoperative day (2.13±0.28) mm. The shrinkage rate of the attached gingiva was 41.22%±5.04%. CONCLUSIONS The application of microscopic surgery on the augmentation surgery of attached gingiva can increase the success rate and improve the quality and quantity of attached gingiva around implants.
Dental Implants ; Gingiva ; surgery ; Humans ; Microsurgery ; Oral Surgical Procedures ; Surgical Flaps