Risk analysis and preventive strategies of implant placement in patients with hypertension / 中华口腔医学杂志

Recently, among the edentulous patients who undergo dental implants, the proportion of hypertensive patients remains high, which poses a greater challenge for clinicians to operate and to maintain the therapeutic effect. The present review comprehensively summarized clinical researches about the adverse effects on dental implants, outlined molecular mechanisms of the positive effects of various antihypertensive drugs on bone metabolism, and proposed that clinicians should select preventive strategies during preoperative and intraoperative procedures according to the blood pressure of patients with hypertension.

Measurement of facial bone wall thickness of maxillary anterior teeth and premolars on cone beam computed tomography images / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To measure the thickness of facial bone wall of maxillary anterior teeth and premolars based on cone beam computed tomography (CBCT) images.</p><p><b>METHODS</b>CBCT images from 118 patients were collected from the Affiliated Stomatology Hospital of Zhejiang University. The thickness perpendicular to the long axis of facial bone wall was measured at two locations: 4 mm apical to the cementoenamel junction (point 1) and the middle of the root (point 2).</p><p><b>RESULTS</b>The thickness of the facial bone walls of central incisors, lateral incisors and canines ranged from 0.5 to 1.5 mm. A thin facial bone wall (<1.0 mm) was quite frequent in central incisors (44.1% at point 1, 56.8% at point 2), lateral incisors (65.2% at point 1, 89.8% at point 2) and canines (45.8% at point 1, 61.0% at point 2). In contrast, the majority of examined first premolars (77.1% at point 1, 68.7% at point 2) and second premolars (94.1% at point 1, 94.1% at point 2) exhibited a thick facial bone wall (>1.0 mm).</p><p><b>CONCLUSION</b>A thin facial bone wall of teeth in the anterior maxilla is common. Radiographic analysis of facial bone wall using CBCT is recommended for selection of appropriate treatment approach.</p>

Analysis of apposition on differently treated implant surface at early stage of implantation / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To compare the surface apposition and the bone response at early period of implantation in two differently treated implants.</p><p><b>METHODS</b>The implants were subject to double acid-etched-H2O2/HCl-heat treatment and double acid-etching treatment, and then randomly implanted into the tibia of rabbits. After 2, 4, 8 weeks of follow up, the bone specimens containing implants were prepared and examined by a field emission SEM and EDX.</p><p><b>RESULT</b>A layer rich with calcium and phosphorus was clearly demonstrated on the implants surface of both groups after 2 weeks of implantation, but it was mostly disappeared after 4 weeks. There were large amounts of osteoblasts cells on double acid-etched-H2O2/HCl-heat treated implants surface indicating the initiation of osteogenesis. After 8 weeks of implantation some new bones were attached on the implants surface in both groups, more bones attached were shown on double acid-etched- H2O2/HCl-heat treated implants surface.</p><p><b>CONCLUSION</b>A calcium and phosphorus-rich layer was formed on the implants surface of both groups at early period of implantation.</p>

Experimental study of fast formation of biomimetic apatite coatings on pure titanium surface / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate calcium-phosphate coating on commercial pure titanium substrate using a fast biomimetic procedure.</p><p><b>METHODS</b>The titanium specimens were divided into two groups, group A and group B. The specimens of group A were only treated with the mixture of H2SO4/HCl for 30 min. The specimens of group B were treated with the mixture of H2SO4/HCl for 30 min, immersed into 5 mol/L NaOH solution at 60 degrees C for 24 h, and then heated to 600 degrees C and maintained for 1 h. All specimens were soaked into simulated body fluid-A (SBF) and SBF-B for each day. The surface morphology was observed by field scanning electron microscopy.</p><p><b>RESULTS</b>Dense calcium-phosphate coating deposited on all the titanium surfaces of two groups. The calcium-phosphate coating consisted of spheric structure with a diameter of 1 approximately 3 microm, which was proved to be hydroxycarbonate apatite with the analysis of X-ray diffraction.</p><p><b>CONCLUSIONS</b>Thin hydroxycarbonate apatite coating can deposited on pure titanium using a fast biomimetic procedure.</p>

Application of bolt-like casting post in posterior fixed partial denture / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To study the manipulation procedure and application of a new post-core system in posterior fixed partial dentures.</p><p><b>METHODS</b>Abutment tooth canals were firstly prepared according to respective canal directions and then complete crown preparation was made following standard procedures. The impression of prepared abutment teeth was taken with silicone and specially made syringe. The fixed partial denture and bolt-like post were fabricated respectively and lastly the two parts were glued together in patient after try-in.</p><p><b>RESULTS</b>All the fixed partial denture with the new post-core system did not get loose and there was no abutment tooth fractured after 23 months in use.</p><p><b>CONCLUSIONS</b>This new post-core system could improve retention of the posterior fixed partial denture if the inter-occlusion distance of the abutment tooth was shorter than 3 mm.</p>

The expression of MMP-9, MMP-2 in the remodeling bone tissue around implant during unloaded period / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To discuss the function of MMP-9, MMP-2 in the remodeling bone tissue around implant during unloaded period.</p><p><b>METHODS</b>At the anterior of the maxilla and mandibular of the Beagle dog, implants were placed at different periods, so the implant specimens of different periods were obtained after dogs were killed. The implant specimens were removed, fixed in 4% paraformaldehyde for 24 hours at 4 degrees C, decalcified with 10% EDTA at pH 7.2, embedded in paraffin wax and sectioned. The observation of the expression changes of the MMP-2, MMP-9 in the milien bone tissue of the implant at different periods were taken by immunohistochemical staining.</p><p><b>RESULTS</b>Matrix metalloprotainase (MMP-9) was mostly expressed at the peripheral cytoplasmic of osteoclast, macrophage, lining cell and fibroblast. MMP-2 was mostly expressed at the peripheral cytoplasmic of osteoblast, fibroblast, some osteoclast also expressed this enzyme.</p><p><b>CONCLUSION</b>MMP-2 and MMP -9 have an important function at the injured bone absorption, healing and bone remodeling after dental implant placement.</p>

Histological observation of the interface of oral epithelium and titanium implant with titanium dioxide on the surface / 浙江大学学报·医学版

OBJECTIVE: To investigate the healing process at the interface between oral epithelium and a titanium implant with titanium dioxide on the surface and whether a good epithelial barrier could be formed. METHODS: Titanium implants with titanium dioxide on the surface were placed in the mandibular alveolar area of Beagle dogs after their premolars had been removed three months previous. On the 15th day, second month and loading second month after implantation specimens were taken and examined after HE staining as well as by transmission electron microscopy. RESULTS: Fifteen days after implantation the epithelial collar was formed, junctional epithelium actively regenerated and attachment to the matrix on the surface of the implant occurred by hemidesmosomes. Two months after implantation junctional epithelium was increasing, showing three to four layers consistent with each other. Junctional epithelium appeared to be generated when stimulated by inflammation and shaped into epithelium rete pegs after loading for two months. CONCLUSION: Oral junctional epithelium can attach very well to titanium implants with titanium dioxide on the surface which also provides a biological barrier.