由支持、稳定和固位浅谈全口义齿印模原理

印模形态决定了未来基托的形态,无牙颌患者的印模制取是全口义齿修复成功的基础。文章分别从基托获得支持、保持稳定、得到良好固位的原理出发,详细阐述与之密切相关的印模制取要点,包括支持区的印模范围和形态、印模边缘伸展与形态、如何处理好印模与软硬组织的关系、取模时应施加的压力等。此外,文章还进一步分析了全口义齿支持、稳定和固位三者之间的关系,旨在强调全口义齿支持和稳定的重要性。     

Can you be too old for oral implants? An update on ageing and plasticity in the oro‐facial sensorimotor system

This review focuses on the capacity of the brain for plasticity and the utility and efficacy of oral implants in helping to restore oro‐facial sensorimotor functions, especially in elderly patients. The review first outlines the components of the oro‐facial sensorimotor system which encompasses both oro‐facial tissues and a number of brain regions. One such region is the sensorimotor cortex that controls the activity of the numerous oro‐facial skeletal muscles. These muscles are involved in a number of functions including reflexes and the more complex sensorimotor functions of mastication, swallowing and speech. The review outlines the use by the brain of sensory inputs from oro‐facial receptors in order to provide for exquisite sensorimotor control of the activity of the oro‐facial muscles. It highlights the role in this sensorimotor control played by periodontal mechanoreceptors and their sensory inputs to the brain, and how oral implants in concert with the plastic capacity of the brain may, at least in part, compensate for reduced sensorimotor functioning when teeth are lost. It outlines findings of ageing‐related decrements in oro‐facial sensorimotor functions and control. The changes in oro‐facial tissues and the brain that underlie these ageing‐related functional alterations are also considered, along with adaptive and compensatory processes that utilise the brain's capacity for plasticity. The review also notes the evidence t hat rehabilitation that incorporates adjunctive approaches such as sensorimotor training paradigms in addition to oral prostheses such as implants may enhance these processes and help maintain or facilitate recovery of sensorimotor functioning in the elderly.     

钛支架修复下颌骨缺损时义齿结构的应力分析

目的:对下颌植入钛支架上义齿支持结构的设计进行分析,提出优化方案.方法:建立在相应缺失牙部位预留孔道的下颌植入钛支架有限元模型.在不同加载力大小的情况下,下颌植入钛支架上不同的义齿支持结构设计时,分析其受力状况.结果:基桩颈部及预留孔径周围的钛板上受力后应力最为集中.从整个钛支架看,应力值较低且分布均匀.颈部的应力值随孔道直径的增加而明显降低.基桩的高度与预留孔道的深度比例对应力的变化基本没有影响.结论:前牙有缺失时,选择预留孔径为2mm,周围钛板厚度为0.5mm.后牙有缺失时,选择预留孔径为4mm,周围钛板厚度为0.5mm.预留孔道的深度可在保证螺纹强度的前提下,尽量减小.根据所得的应力分布情况,可对钛板进行支架式的设计.     

正畸移动大鼠牙过程牙周组织中PLAP-1、BMP-2的表达及意义

目的:研究正畸移动大鼠上后牙过程中,PLAP-1、BMP-2在牙周膜的分布和表达。方法:选择雄性SD大鼠36只,按1d、3d、5d、7d、14d、21 d分为6组,均用50 g移动左上第一磨牙,右上第一磨牙为对照。在相应时期处死大鼠后测量牙移动距离,采用HE染色及免疫组织化学SP法,检测不同时期牙周组织的形态变化; PLAP-1、BMP-2在牙周膜组织中的表达及研究两者可能存在的关系。结果:不同时期牙移动的距离不同,差别显著有统计学意义(P<0.05)。 HE染色显示对照组牙周组织变化不明显;实验组张力区有成骨细胞生成,压力区破骨细胞生成,随着时间的延长最后两区形态都基本趋一致。免疫组化法示PLAP-1在牙周膜的表达总是张力区高于压力区,在第3天张力区表达最强,除21 d外,其余各组间差异显著有统计学意义(P<0.05)。BMP-2在第5天张力侧表达最强,在3 d、5 d、7 d的表达差异显著有统计学意义(P<0.05)。结论:PLAP-1,BMP-2在正畸力作用下参与牙周膜组织改建的表达最高值时期不同。     

Indications for the scapular flap in reconstructions of the head and neck

Composite free flaps that are available for reconstructions of the head and neck include those from the fibula, iliac crest, radial forearm, and scapula, but only that from the scapula precludes two-team operating, and consequently adds a further 2–3 h to the operating time. Here we clarify the indications for the subscapular system of composite flaps, and discuss their unique properties in terms of reliability of the bony segment, their resistance to atherosclerosis, and the diversity of the skin and muscular components that are available. We have had favourable results in composite resections of the anterior mandible that required substantial resections of the anterior tongue. In extensive oropharyngeal resections that require a segmental resection of the mandible, the skin island is reliable and provides sufficient bulk to reduce the risk of dehiscence and maintain a narrowed oropharynx to improve speech and swallowing. In reconstructions of the midface a combination of the latissimus dorsi and the scapula that is based on the angular branch of the thoracodorsal vessel (thoracodorsal angular flap) allows for a long pedicle, and adequate muscle and bone for high and low maxillectomy defects. We present a consecutive series of 46 patients who document the use of this option in routine head and neck practice.     

Shaping ability of NT Engine and McXim rotary nickel-titanium instruments in simulated root canals. Part 2

The aim of this laboratory-based study was to determine the shaping ability of NT Engine and McXim nickel-titanium rotary instruments in simulated root canals. A total of 40 canals with four different shapes in terms of angle and position of curve were prepared with NT Engine and McXim instruments, using the technique recommended by the manufacturer. Part 2 of this report describes the efficacy of the instruments in terms of prevalence of canal aberrations, the amount and direction of canal transportation and overall postoperative shape. Pre- and postoperative images of the canals were taken using a video camera attached to a computer with image analysis software. The pre- and postoperative views were superimposed to highlight the amount and position of material removed during preparation. No zips, elbows, perforations or danger zones were created during preparation. Forty-two per cent of canals had ledges on the outer aspect of the curve, the majority of which (16 out of 17) occurred in canals with short acute curves. There were significant differences (P<0.001) between canal shapes in terms of the incidence of ledges. There were highly significant differences (P<0.001) between the canal shapes in total canal width at specific points along the canal length and in the amount of resin removed from the inner and outer aspects of the curve. The direction of canal transportation at the endpoint of preparation was most frequently towards the outer aspect of the curve, especially in canals with 40° curves. At the beginning of the curve, transportation in the majority of canals was towards the inner aspect of the curve. Mean absolute transportation was less than 0.03 mm throughout the curve and towards the endpoint, with significant differences between canal shapes occurring at the apex (P<0.05) and at the beginning of the curve (P<0.001). Under the conditions of this study, NT Engine and McXim rotary nickel–titanium instruments created no aberrations other than ledges and produced only minimal transportation. The overall shape of canals was good.     

乙醇浴“一步交联”法制备明胶三维大孔纳米纤维支架

目的:探讨采用乙醇浴“一步交联”法制备静电纺丝水溶性大分子纤维支架。方法:分别采用乙醇浴“一步交联”法和“二步交联”法制备明胶静电纺丝纤维,分析两种方法对纤维形貌、结构、交联度及稳定性的影响。结果:与“二步交联”纤维相比,“一步交联”法收集的明胶纤维直径更细,孔隙更大,吸水率更高,能维持纤维及支架的结构。通过对交联剂浓度及交联时间进行调整,可以改变纤维的交联度。“一步交联”纤维已具有良好的稳定性,无需再进行交联处理。结论:乙醇浴“一步交联”技术能有效维持明胶纤维的形貌及结构,提高交联效率,制备出较理想的三维大孔纳米支架。     

上颌埋伏倒置中切牙3例及文献复习

目的探讨上颌埋伏倒置中切牙病例的临床特点、诊断及治疗方法,以期为临床诊治提供参考。 方法回顾性分析南方医科大学附属深圳妇幼保健院2017—2019年期间收治的3例上颌埋伏倒置中切牙患者的临床表现、影像学表现、治疗方法及治疗效果,并进行相关文献复习。 结果3例上颌埋伏倒置中切牙病例主要表现为单侧上颌中切牙缺失、邻牙倾斜、缺牙间隙变小,锥形束CT（CBCT）检查均发现缺隙处有1颗唇侧倒置埋伏中切牙,其中1例牙根根尖孔已闭合,另外2例牙根发育至根尖1/2 ~ 1/3,现有冠根比≥1∶1,牙根弯曲部分在根尖1/2 ~ 1/3。3例均采用外科开窗联合正畸牵引进行治疗,患牙均顺利进入牙列,无松动,咬合良好,未出现明显牙根吸收。 结论上颌埋伏倒置中切牙的矫治难度较大,应掌握其临床特点及治疗原则,重视矫治时机的选择及矫治方法设计,提高患牙保存率。     

橡皮障隔离技术

在牙髓治疗和牙体修复过程中，有效地将患牙与口腔环境隔离，保持术区干燥，阻止唾液及微生物对术区的污染，是治疗和修复成功的基本保证。随着技术的发展与革新，橡皮障隔离技术已成为目前最有效的隔离方法，是治疗过程中不可或缺的关键步骤。因此，了解橡皮障的优势、组成，掌握橡皮障的应用方法，对于提高治疗成功率、减少并发症的发生具有十分重要的意义。     

抗菌钛合金在口腔医学中应用研究进展

广泛应用于口腔医学领域的钛合金,由于长期处于复杂微生物环境中,材料表面易形成细菌生物膜,影响其使用效率和寿命。抗菌钛合金是一种通过表面改性或整体改性的方法添加了抗菌剂的新型钛合金。根据抗菌剂在钛合金材料中分布的位置,抗菌钛合金分为涂层型和合金型。涂层型抗菌钛合金的抗菌效果良好,但缺点是涂层大多不耐磨;合金型抗菌钛合金的抗菌剂一般为金属元素,可在合金中均匀分布,抗菌性能稳定持久。根据抗菌钛合金能否释放抗菌剂,分为主动抗菌型和被动抗菌型,主动抗菌型钛合金可释放负载的抗菌剂,抗菌效果比较明显,但有些抗菌剂的释放时间较短;被动抗菌型钛合金不释放抗菌剂,通过接触杀菌或抑制细菌黏附的方式产生抗菌作用。抗菌钛合金可抑制材料表面细菌黏附,对延长矫治器、种植体、钛板等在口腔内的使用寿命具有重要意义,且抗菌改性后钛合金的机械性能未受明显影响,羟基磷灰石等抗菌剂的加入还提高了材料的成骨功能,在种植义齿、正畸矫治及口腔颌面外科等口腔医学领域应用前景良好。但是,目前关于抗菌钛合金的研究大多是体外实验,其长期的临床效果及其抗菌机制仍不明确,有待深入研究。     

美学区种植修复体穿龈轮廓设计

获得理想粉色美学效果是美学区实现成功种植治疗的重要条件之一。在前牙美学区种植后为获得良好的美学效果,临床中可通过临时修复体引导软组织塑形来实现。由于种植体周围组织与天然牙周组织存在明显差异,修复体穿龈轮廓的形状和尺寸将对种植体周围软硬组织美学、健康和稳定产生重大影响。当设计不当时,穿龈轮廓将影响该区域的血液供应、疾病的检测和专业维护措施的实施,从而导致种植体周围组织体积的损失和疾病的发生。透彻地了解种植修复体周围组织的生物学特点以及修复体穿龈外形设计原则有助于修复医生通过修复体对软组织进行可预测的管理和塑形来实现种植体周围组织稳定的美学、功能和健康状态。     

Electrochemical and spectroelectrochemical characterization of lipid organization in an electric field

The characterization of the adsorption/desorption of water insoluble surfactants onto an electrified interface is reviewed. Electrochemical and spectroelectrochemical investigations of the role of potential in controlling the nature of the surfactant present at the interface is described. The adsorption of octadecanol, cis-9-octadecenol onto Au(1 1 1) and the adsorption of DOPC (from a monolayer or from a dispersion of liposomes) onto Hg are used as examples. A general mechanism was proposed to describe the potential-dependent phase changes, desorption and subsequent readsorption process that links the results from impedance, fluorescence and elastically scattered light measurements of the surfactant-modified interface. This proposed mechanism and results from fluorescence microscopy results were used to describe the creation of a hybrid adsorbed hemi-liposomal layer onto a Hg surface. The implications for thermodynamic analysis via the electrocapillary equation for this class of surfactants were discussed. The relevance of the general mechanism towards the reductive desorption of alkyl thiol SAMs was also outlined.     

L’estetica del sorriso e del volto: fattori determinanti, canoni di riferimento e cambiamenti con l’età

Objectives. To illustrate some of the fundamental orthodontic guidelines for maintaining the harmony of the dento-periodontal unit and the face, which includes a dynamic component: the smile. Materials and methods. This dossier examines the golden ratio of dental to gingival components in the smile; the relationships between teeth, gums, and lips in the dynamic smile; the effects on the smile of excessively large buccal corridors and their relation to the position of the teeth within the dental arches; and the role of the smile the overall facial esthetics. It also reviews the modifications that will be produced by aging in the soft and hard tissues of the face, for the orthodontist must always evaluate the patients face prospectively: not only as it appears at the time of treatment, but also as it will appear after the passage of time. Results and conclusions. Esthetics is a relative concept, and it is difficult to establish rigid guidelines for producing a beautiful smile and a beautiful face. However, orthodontics has introduced some general rules that can help maintain the harmony of the face through the dynamic component of the smile.     

Guidelines for the management of traumatic dental injuries. II. Avulsion of permanent teeth

Abstract –  Avulsion of permanent teeth is the most serious of all dental injuries. The prognosis depends on the measures taken at the place of accident or the time immediately after the avulsion. Replantation is the treatment of choice, but cannot always be carried out immediately. An appropriate emergency management and treatment plan is important for a good prognosis. Guidelines are useful for delivering the best care possible in an efficient manner. The International Association of Dental Traumatology (IADT) has developed a consensus statement after a review of the dental literature and group discussions. Experienced researchers and clinicians from various specialties were included in the group. In cases in which the data did not appear conclusive, recommendations were based on the consensus opinion of the IADT board members. The guidelines represent the current best evidence based on literature research and professional opinion. In this second article of three, the IADT Guidelines for management of avulsed permanent teeth are presented.     

Assessment of mesiodistal tooth angulation on the panoramic radiograph

Tilting of the head has been suggested as a potential source of error when the clinician assesses the angulation of teeth in the panoramic radiograph. If a reference line that could be stable in variations of head positioning during the radiographic exposure could be found, then the examination of the radiograph would be more accurate. We examined the effects of three different head positions on the panoramic image in ten volunteer patients. Our findings suggest that the upper and lower margins of the film are useful reference lines in estimating the mesiodistal angulation of six anteriors, and the mandibular plane is more useful in assessing the angulations of posterior teeth and canines.     

Prevalence and incidence of oral lesions--the changing scene

A range of oral mucosal and periodontal lesions is associated with HIV infection and HIV disease progression. These are often symptomatic and require treatment in themselves, and also have a diagnostic and prognostic role in the management of the underlying HIV disease. These lesions have been broadly divided into: (a) those strongly associated with HIV such as oral candidoses, oral hairy leukoplakia and Kaposi's sarcoma; (b) those less strongly associated such as swellings of the major salivary glands; and (c) those least commonly associated such as recurrent aphthous ulcers. Overall the prevalence and severity of these lesions inversely correlate with the level of immunosuppression. With the passage of time, there has been improved understanding of the disease pathogenesis resulting in the development of new drugs to combat this infection. Medication has changed from monotherapy to current triple combination therapy (Highly Active Anti-Retroviral Therapy). This review looks at the impact of changing therapy on the prevalence of the various oral lesions associated with HIV. It finds a decrease in the prevalence of the oral lesions in the era of combination therapy as compared to earlier periods. It also shows a change in the types of lesions which predominate with those previously placed amongst the strongly associated lesions no longer being predominant in the era of combination therapy where such treatment is available.     

Bone tissue formation adjacent to implants placed in fresh extraction sockets: an experimental study in dogs

OBJECTIVE: To study the healing of marginal defects that occurred at implants placed in a healed ridge or in fresh extraction sockets. MATERIAL AND METHODS: Six dogs were used. The right side of the mandible was used in the first part of the study. The first, second premolars and first molars were extracted. After 3 months of healing the bone was prepared for implant installation in these premolar and molar sites. The marginal 5 mm of each recipient site was widened with a conical drill. Following implant installation a gap of varying dimension occurred around the titanium rod (artificial defect (A) sites). At this interval the third and fourth premolars were extracted and implants were installed in the distal socket of the two teeth (natural defect (N) sites). The flaps were sutured to allow non-submerged healing. After 2 months, the procedures were repeated in the left side. Two months later the animals were euthanized, and biopsies were obtained and prepared for histological examination. RESULTS: The length of the zone of de novo'bone-to-implant contact' in the defect region was longer at the A sites than at the N sites both at the 2- and the 4-month interval. Further, while after 4 months of healing the marginal bone crest at the A sites was located close to the abutment/fixture junction, at the N sites a marked reduction of the height of the bone crest was documented. Hence, most A site defects became completely resolved whereas healing of the N site defects was incomplete. CONCLUSION: The process of bone modeling and remodeling at an implant placed in a fresh extraction socket differs from the resolution of marginal defects that may occur following implant installation in a healed ridge.