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@#The standardized workflow of computer-aided static guided implant surgery includes preoperative examination, data acquisition, guide design, guide fabrication and surgery. Errors may occur at each step, leading to irreversible cumulative effects and thus impacting the accuracy of implant placement. However, clinicians tend to focus on factors causing errors in surgical operations, ignoring the possibility of irreversible errors in nonstandard guided surgery. Based on the clinical practice of domestic experts and research progress at home and abroad, this paper summarizes the sources of errors in guided implant surgery from the perspectives of preoperative inspection, data collection, guide designing and manufacturing and describes strategies to resolve errors so as to gain expert consensus. Consensus recommendation: 1. Preoperative considerations: the appropriate implant guide type should be selected according to the patient's oral condition before surgery, and a retaining screw-assisted support guide should be selected if necessary. 2. Data acquisition should be standardized as much as possible, including beam CT and extraoral scanning. CBCT performed with the patient’s head fixed and with a small field of view is recommended. For patients with metal prostheses inside the mouth, a registration marker guide should be used, and the ambient temperature and light of the external oral scanner should be reasonably controlled. 3. Optimization of computer-aided design: it is recommended to select a handle-guided planting system and a closed metal sleeve and to register images by overlapping markers. Properly designing the retaining screws, extending the support structure of the guide plate and increasing the length of the guide section are methods to feasibly reduce the incidence of surgical errors. 4. Improving computer-aided production: it is also crucial to set the best printing parameters according to different printing technologies and to choose the most appropriate postprocessing procedures.
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@#The rapid absorption of labial alveolar bone after tooth extraction not only reduces the aesthetic effect of implant repair but also affects the long-term success rate of implants. The socket shield technique is reported as the latest alveolar preservation technique in the aesthetic zone from both domestic and international case reports and shows a high success rate of short-term osseointegration and excellent aesthetic effects. However, some investigations have shown short- and long-term complications with the socket shield technique, such as failure of osseointegration, loss of crestal bone and buccal bone, inflammation, etc. In this review, the socket shield technique will be reported in detail with its pros and cons. Although the socket shield technique has achieved good clinical effects and short-term success rates in many cases, there are still no conclusions regarding the surgical procedure, such as the thickness, the position of the shield, whether to put the graft material between the shield and implant, etc. Due to the lack of long-term research or a large amount of clinical literature support and technical sensitivity, the socket shield technique should be carefully used in clinical application to reduce unexpected risks.
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@#With the rapid development of implant technology, implant restoration is a conventional treatment option for adult patients with tooth loss. Severe dental lesions, trauma, tumors, abnormal development and other reasons can cause dental defects and even dentition loss in children and adolescents. There has been hesitation to perform implant therapy for growing children because of the growth period; thus, little is known about the outcomes of the osseointegration procedure in young patients. Therefore, this article reviews the current literature to discuss the use of dental implants in children and adolescents. According to current studies, orthodontic treatment or transitional restoration should be undertaken based on the characteristics of the children and adolescents. Implant surgery should be performed after the end of the peak growth period. For patients with severe dentition defects, relevant criteria should be established before implant surgery to evaluate the effect of implant therapy in children and adolescents. The patients should be treated with a multidisciplinary, staged and long-term treatment approach. Most of the recent literature consists of case reports and short-term studies. There is an urgent need for more studies in this field with long-term follow-up.
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@#The crown-root ratio (C/R) theory of natural teeth has been widely recognized in the field of stomatology,and has important clinical significance in predicting and assessing the prognosis of natural teeth as well as for abutment selection during denture restoration. In the past few decades, scholars have advocated for the implantation of implants as long in length as possible to improve the success rate according to the theory of crown-root ratio of natural teeth. However, with the application of short implants, our philosophy of implantation has changed, and the relationship between the crown-implant (C/I) ratio and complications has become one of the current research hotspots. In this paper, the concept of the crown-implant ratio, the research progress of the C/I ratio, the implant survival rate and clinical complications of implant restoration were reviewed and summarized, and the following suggestions were put forward: although most studies have shown no significant correlation between the C/I ratio and implant survival or marginal bone loss, this relationship may increase the risk of mechanical complications. A C/I < 3 and a crown length < 15 mm are recommended in implant restoration; when ultra-short implants are applied, the implant system can increase the bone-to-implant contact area, and splint prostheses such as crown or bridge are recommended.
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Objective @# To investigate the effect of a laser-etched pure titanium surface on proliferation of the human osteosarcoma cell line MG63 and to provide a basis for study of implant surface modification. @*Methods@#The pure titanium plate was cut into titanium pieces by a numerical control machine tool and divided into smooth surface and laser etching groups. The titanium surface of the laser etching group was etched with an Nd:YAG continuous wave laser using predetermined parameters, and the surfaces were observed by scanning electron microscopy (SEM). The surface micromorphology of each titanium sheet was evaluated. The relative element content of the titanium surface was measured by energy dispersive X-ray spectroscopy (EDS). The Ra value of each surface was determined using the Veeco roughness tester. MG63 cells were inoculated on 2 sets of titanium tablets. At 1, 3, and 6 h postinoculation, cell adhesion to the two groups of titanium sheets was observed under the microscope. At 24 h after inoculation, cellular F-actin was directly stained using immunofluorescence, and the morphology of the cytoskeleton was observed by laser confocal microscopy. Cell proliferation was examined at 1, 3, and 5 d using a MTS kit, and the data were analyzed with SAS 9.4.@* Results @#The surface of the smooth surface group was smooth and flat, the element composition was pure titanium, and the roughness Ra was 179.23 nm. The surface of the laser-etched group formed a regular and uniform pore structure. The composition was mainly Ti, O, C, etc, and the surface roughness Ra was 14.11 μm. A large number of cells were uniformly distributed on the two titanium sheets in the observations at 1, 3, and 6 h. At 24 h postinoculation, MG63 cells were completely stretched on the two sets of titanium sheets and had extended a large number of pseudopods and microfilaments to cross-link with peripheral cells; moreover, the cell division phase was observed. The cell proliferation of the two groups at 1, 3, and 5 d showed a significant increase with time, indicating that no cytotoxicity occurred on the surfaces of the two groups. However, the cell proliferation in the laser-etched group was superior to that in the mechanical smooth surface group.@*Conclusion@#The surface morphology of titanium can be controlled by laser etching, which is conductive to increase the microstructure of implants without cytotoxicity and promoting osteoblast proliferation in the early stage.
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Objective @# To explore the clinical effect of the alveolar crest approach in the treatment of odontogenic maxillary sinusitis and the repair of edentulous implants in this area.@*Methods@#This was a retrospective case series of 20 patients with odontogenic sinusitis. The pathogenesis in each case was investigated. After elimination of the dental origin, each patient was treated with flushing, drainage and anti-inflammatories through the alveolar crest approach. Postoperative CBCT reexamination was performed to evaluate the therapeutic effect. Maxillary sinus elevation surgery with simultaneous or delayed implantation was performed after maxillary sinusitis healing was confirmed. The patients were followed postoperatively.@*Results @#Twenty patients with odontogenic sinusitis were treated by the alveolar crest approach, and 17 were cured, for a cure rate of 85%. Among them, 17 of the maxillary sinusitis patients were followed for 1 year, with good results.@*Conclusion @#The alveolar crest approach is feasible for the treatment of odontogenic maxillary sinusitis and can serve as a minimally invasive method for the repair of edentulism in this area and implantation.
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Objective@#To study the vascularization of the collagen-binding basic fibroblast growth factor (bFGF)-loaded collagen membranes in soft tissue repair in the hard palates of rats. @*Methods@#Ninety-six male 6-week-old Wistar rats were randomly divided into 4 groups, and 3-mm-diameter circular soft tissue defects were produced from the distal surface of the third molar to the mesial surface of the first molar in their hard palates. The defects were covered with a collagen-targeting bFGF/collagen membrane, a free bFGF/collagen membrane, a collagen membrane or no membrane (control group). Every 6th rat was randomly sacrificed at 1, 2, 4 and 8 weeks in every group after surgery. Wound healing and the number of new blood vessels were measured by hematoxylin-eosin (HE) staining. @*Results @#The numbers of new blood vessels in the collagen-targeting bFGF/collagen membrane group were 8.94 ± 0.61, 17.39 ± 2.08 and 11.22 ± 1.66 at 1, 2 and 4 weeks after surgery, respectively, which were significantly greater than the values in the other groups (P<0.05). At 8 weeks, the number of new blood vessels in the collagen-targeting bFGF/collagen membrane group was 4.17 ± 1.28, and there was no significant difference in the numbers of new blood vessels between any of the groups (P > 0.05).@*Conclusion@#Collagen-targeting bFGF/collagen membranes had a favorable effect on promoting angiogenesis during wound healing, and promoted wound healing.
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@#Because nanoparticles have particular characteristics, such as small size and surface effects, nano-TiO2 is widely used in air purification, wastewater treatment and self-cleaning. In recent years, TiO2 photocatalysis has thoroughly explored as a new titanium implant surface treatment method. Photocatalytic performance is better for TiO2 nanowires than for nano-TiO2 particles. Hence, these nanowires have received widespread attention with regard for their more specific surface area and surface energy, improved charge carrier transport efficiency, and enhanced charge collection efficiency. Photon-generated carrier transport moves in a one dimensional straight path along a nanowire, and this could decrease photoelectron loss. In this paper, we summarized the principles underlying, factors that influence, and applications involving TiO2 nanowire photocatalysis. Additionally, we describe its method of preparation and toxicity.
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Objective@#To investigate the effect of pure titanium surface of large diameter TiO2 nanotubes modified by RGD peptide on the adhesion and proliferation of MG63 osteoblasts. to provide theoretical proof for developing titanium implants.@*Methods@#Commercially pure titanium discs were divided into four groups and treated with SLA to obtain a microrough surface (SLA group). Then, nanotubes were imposed on this microrough surface by anodization (SLA+80 group). The surface was then modified by dopamine (DOPA) (DOPA Group), after which bioactive RGD peptide layers were generated on the TiO2 nanotube surfaces via electrochemical and molecular self-assembly techniques (RGD group). The titanium surface morphology and elemental composition of each group were characterized by field emission scanning electron microscopy (FE-SEM) and X-ray photoelectron spectroscopy (XPS). MG63 cells were cultured in vitro to evaluate biological activities of titanium before and after treatment, including the evaluation of early-stage cell adhesion capacity by fluorescence microscopy, proliferation capacity by MTS assay, and mRNA expression of the cell osteoblast-related genes alkaline phosphatase (ALP) and osteocalcin (OCN) by qRT-PCR.@*Results@#FE-SEM and XPS showed that hierarchical micro/nanosurfaces decorated with TiO2 nanotubes were produced on titanium using sandblasting and large grit etching combined with anodization, dopamine was then self-polymerized to form a polydopamine film on the TiO2 nanotube surfaces, and RGD peptides were then conjugated to the polydopamine film, finally forming RGD peptide-modified bioactive layers. In vitro experiments showed that compared with the other three materials, the RGD-modified material was more conducive to cell adhesion and proliferation (P < 0.05). The expression levels of ALP and OCN mRNA in the RGD group were significantly higher than those in the SLA group and DOPA group (P < 0.05).@*Conclusion@#Hierarchical micro/nanosurfaces decorated with TiO2 nanotubes functionally modified with RGD peptides have good biocompatibility and could be used for developing titanium implants and further improving early osseointegration.