Clinical and pathological aspects on some odontogenic tumors

Odontogenic tumors constitute a very diverse group of lesions that reflects the complex processes of odontogenesis. Controversies over their classification/subtyping, terminology and diagnosis have been persisted, which has direct bearings on therapeutic and/or prognostic implications.     

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.     

Tumor microenvironment in oral cancer: novel approaches for immunotherapy

Squamous cell carcinoma of the head and neck (SCCHN), which arises from the squamous mucosal epithelium of the oral cavity, pharynx and larynx, is a major health problem in the US and other parts of the world, especially in developing countries.     

牙槽骨再生正畸治疗伴牙槽骨缺损的成人错畸形远期疗效评价

目的：评价牙槽骨再生正畸治疗伴牙槽骨缺损的成人错畸形的远期疗效。方法伴牙槽骨缺损的成人错畸形3例,平均年龄29岁。经正颌-正畸联合会诊制订治疗计划,按照牙槽骨再生正畸及正颌-正畸联合治疗模式,分别进行系统治疗并随访2~3 a。结果3例患者均顺利完成治疗,面型及咬合关系获得良好改善;牙槽骨缺损区正畸牙移动到位且未见医源性牙周并发症,牙槽骨缺损区骨量增加明显且远期效果稳定。结论针对伴牙槽骨缺损的成人患者,牙槽骨再生正畸是一种较为理想的技术。     

Management of acute open flexor tendon injuries of the hand and wrist: basic sciences,surgical factors and rehabilitation pertinent to optimizing outcome

Flexor tendon injuries to the hand and wrist represent a significant resource burden to the UK NHS. A good understanding of tendon basic science and repair techniques is crucial for the surgeon undertaking their repair and rehabilitation. Furthermore, this is a common topic assessed in the FRCS(Orth) examination. This article will summarize the basic science relating to tendon structure, physiology and injury. Additionally, it will present key surgical and rehabilitation factors relevant to clinical outcomes.     

In vitro calibration and validation of a digital subtraction radiography system using scanned images

OBJECTIVES: To calibrate and validate a digital subtraction radiography system using scanned images for quantification of alveolar bone changes by means of computer-assisted densitometric image analysis (CADIA) in vitro. MATERIALS AND METHODS: Noise levels were determined using 10 standardized periapical radiographs of the same lower molar region in a human dry skull. For validation of the system, radiographs were taken before and after bovine bone particles in measures with increments of 2 mg weighing from 2 to 20 mg were added into each socket of three dry skulls. Radiographs were developed and scanned into a computer with a flatbed scanner. After digitization, the images were subjected to alignment, normalization and subtraction. Appropriate regions of interest (ROIs) were selected and their CADIA values were calculated for the determination of noise levels, and correlations between the CADIA values and the actual bone mass were performed. RESULTS: When the threshold value was 7, the percentage of pixels deviating from the set threshold value was small (0-11.3%). There were statistically significant correlations between the actual bone mass and the CADIA value for anterior sockets (p<0.001, r2=0.89) and posterior sockets (p<0.001, r2=0.9). For pooled data of both anterior and posterior sockets, the correlation was also statistically significant (p<0.001, r2=0.88). CONCLUSIONS: A high and statistically significant correlation between the actual bone mass and CADIA value was obtained, which suggests that the system could be suitable for the detection of small alveolar bone changes.     

伴囊肿的上颌埋伏阻生中切牙早期引流助萌治疗

目的:探讨采用引流助萌的方法对伴囊肿的上颌埋伏阻生中切牙的早期治疗。方法:选取单侧上颌中切牙埋伏阻生、处于替牙早期伴囊肿的患者8例。外科囊肿切除同时对埋伏阻生上颌中切牙引流助萌治疗。治疗前后拍摄CBCT,Dolphin11.0软件测量矫治前后阻生牙及对侧正常同名牙的冠根长度。结果:8例患者的埋伏阻生上颌中切牙平均矫治时间6.7个月。矫治后阻生牙和对侧正常同名牙的冠根长度均有生长。阻生牙冠根长度较对侧正常同名牙明显短(P<0.05)。结论:本研究所采用引流助萌方法为埋伏阻生牙的矫治提供了一个安全、有效的新途径。     

Fabrication and characterisation of a novel biomimetic anisotropic ceramic/polymer-infiltrated composite material

Objective

To fabricate and characterise a novel biomimetic composite material consisting of aligned porous ceramic preforms infiltrated with polymer.

The influence of a biomaterial on the closure of a marginal hard tissue defect adjacent to implants. An experimental study in the dog

OBJECTIVES: The present experiment was performed to determine the influence of Bio-Oss on hard tissue formation at sites that, following implant installation, presented a 1-1.25 mm wide marginal defect. MATERIAL AND METHODS: Four Labrador dogs were used. The premolars and first molars on both sides of the mandible were extracted. After 3 months, mucoperiosteal flaps were elevated and three experimental sites were prepared for implant installation in each side of the mandible. A step drill was used to widen the marginal 5 mm of the canal. Thus, following the placement of the implant (3.3 x 10 mm, SLA surface, Straumann AG, Waldenburg, Switzerland) a circumferential gap, about 1-1.25 wide and 5 mm deep, remained lateral to the titanium rod. The test sites in the left side of the mandible were first filled with a deproteinized cancellous bone mineral (Bio-Oss). The defect sites in the right side of the mandible (control sites) were left for spontaneous healing. A resorbable barrier membrane (Bio-Gide) was placed to cover the implant and the bone tissue in two sites of each quadrant, while the third site was left without membrane placement. The flaps were repositioned to cover all defect sites and were sutured. After 4 months of healing, block biopsies of each implant site were dissected and processed for ground sectioning. RESULTS: It was demonstrated that at 4 months, all types of defects were filled with newly formed bone and that the biomaterial placed in the marginal defect in conjunction with implant installation during healing became incorporated in the newly formed bone tissue. A high degree of contact was established between the Bio-Oss particles and the newly formed bone. CONCLUSION: Bio-Oss became integrated with the newly formed bone. In the model used, Bio-Oss did not enhance the process of bone formation and defect closure.     

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。     

Melatonin-doped polymeric nanoparticles reinforce and remineralize radicular dentin: Morpho-histological,chemical and biomechanical studies

ObjectivesTo investigate the effectiveness of novel polymeric nanoparticles (NPs) doped with melatonin (ML) in reducing dentin permeability and facilitating dentin remineralization after endodontic treatment.MethodsThe effect of undoped NPs and ML-doped NPs (ML-NPs) was tested in radicular dentin, at 24 h and 6 m. A control group without NPs was included. ML liberation was measured. Radicular dentin was assessed for fluid filtration. Dentin remineralization was analyzed by scanning electron microscopy, AFM, Young’s modulus (Ei), Nano DMA-tan delta, and Raman analysis.ResultsML release ranged from 1.85 mg/mL at 24 h to 0.033 mg/mL at 28 d. Both undoped NPs and ML-NPs treated dentin exhibited the lowest microleakage, but samples treated with ML-NPs exhibited hermetically sealed dentinal tubules and extended mineral deposits onto dentin. ML-NPs promoted higher and durable Ei, and functional remineralization at root dentin, generating differences between the values of tan delta among groups and creating zones of stress concentration. Undoped-NPs produced closure of some tubules and porosities at the expense of a relative mineral amorphization. Chemical remineralization based on mineral and organic assessments was higher in samples treated with ML-NPs. When using undoped NPs, precipitation of minerals occurred; however, radicular dentin was not mechanically reinforced but weakened over time.SignificanceApplication of ML-NPs in endodontically treated teeth, previous to the canal filling step, is encouraged due to occlusion of dentinal tubules and the reinforcement of the radicular dentin structure.     

Tannerella forsythia‐produced methylglyoxal causes accumulation of advanced glycation endproducts to trigger cytokine secretion in human monocytes

The periodontal pathogen Tannerella forsythia has the unique ability to produce methylglyoxal (MGO), an electrophilic compound which can covalently modify amino acid side chains and generate inflammatory adducts known as advanced glycation endproducts (AGEs). In periodontitis, concentrations of MGO in gingival‐crevicular fluid are increased and are correlated with the T. forsythia load. However, the source of MGO and the extent to which MGO may contribute to periodontal inflammation has not been fully explored. In this study we identified a functional homolog of the enzyme methylglyoxal synthase (MgsA) involved in the production of MGO in T. forsythia. While wild‐type T.forsythia produced a significant amount of MGO in the medium, a mutant lacking this homolog produced little to no MGO. Furthermore, compared with the spent medium of the T. forsythia parental strain, the spent medium of the T. forsythia mgsA‐deletion strain induced significantly lower nuclear factor‐kappa B activity as well as proinflammogenic and pro‐osteoclastogenic cytokines from THP‐1 monocytes. The ability of T. forsythia to induce protein glycation endproducts via MGO was confirmed by an electrophoresis‐based collagen chain mobility shift assay. Together these data demonstrated that T. forsythia produces MGO, which may contribute to inflammation via the generation of AGEs and thus act as a potential virulence factor of the bacterium.     

Two Palatal Root Canals in a Maxillary Right Second Molar： One Case Report

牙根和根管的数目不是固定不变的,文献报道表明牙齿尤其是上颌磨牙根管存在着解剖变异。但是,上颌第二磨牙发生腭根双根管的可能性很低。在本文中,作者报道了一例右上颌第二磨牙腭根双根管的解剖变异。由于可能存在的上颌第二磨牙腭根管解剖变异,所以临床医生在牙髓病治疗过程中应注意术前对患牙进行影像学分析,术中可借助牙科手术显微镜等可视手段寻找可能存在的腭根解剖变异。     

Potential role for Streptococcus gordonii‐derived hydrogen peroxide in heme acquisition by Porphyromonas gingivalis

Streptococcus gordonii, an accessory pathogen and early colonizer of plaque, co‐aggregates with many oral species including Porphyromonas gingivalis. It causes α‐hemolysis on blood agar, a process mediated by H₂O₂ and thought to involve concomitant oxidation of hemoglobin (Hb). Porphyromonas gingivalis has a growth requirement for heme, which is acquired mainly from Hb. The paradigm for Hb heme acquisition involves the initial oxidation of oxyhemoglobin (oxyHb) to methemoglobin (metHb), followed by heme release and extraction through the actions of K‐gingipain protease and/or the HmuY hemophore‐like protein. The ability of S. gordonii to mediate Hb oxidation may potentially aid heme capture during co‐aggregation with P. gingivalis. Hemoglobin derived from zones of S. gordonii α‐hemolysis was found to be metHb. Generation of metHb from oxyHb by S. gordonii cells was inhibited by catalase, and correlated with levels of cellular H₂O₂ production. Generation of metHb by S. gordonii occurred through the higher Hb oxidation state of ferrylhemoglobin. Heme complexation by the P. gingivalis HmuY was employed as a measure of the ease of heme capture from metHb. HmuY was able to extract iron(III)protoporphyrin IX from metHb derived from zones of S. gordonii α‐hemolysis and from metHb generated by the action of S. gordonii cells on isolated oxyHb. The rate of HmuY‐Fe(III)heme complex formation from S. gordonii‐mediated metHb was greater than from an equivalent concentration of auto‐oxidized metHb. It is concluded that S. gordonii may potentially aid heme acquisition by P. gingivalis by facilitating metHb formation in the presence of oxyHb.     

Masticatory muscle sleep background electromyographic activity is elevated in myofascial temporomandibular disorder patients

Despite theoretical speculation and strong clinical belief, recent research using laboratory polysomnographic (PSG) recording has provided new evidence that frequency of sleep bruxism (SB) masseter muscle events, including grinding or clenching of the teeth during sleep, is not increased for women with chronic myofascial temporomandibular disorder (TMD). The current case–control study compares a large sample of women suffering from chronic myofascial TMD (n = 124) with a demographically matched control group without TMD (n = 46) on sleep background electromyography (EMG) during a laboratory PSG study. Background EMG activity was measured as EMG root mean square (RMS) from the right masseter muscle after lights out. Sleep background EMG activity was defined as EMG RMS remaining after activity attributable to SB, other orofacial activity, other oromotor activity and movement artefacts were removed. Results indicated that median background EMG during these non‐SB event periods was significantly higher (P < 0·01) for women with myofascial TMD (median = 3·31 μV and mean = 4·98 μV) than for control women (median = 2·83 μV and mean = 3·88 μV) with median activity in 72% of cases exceeding control activity. Moreover, for TMD cases, background EMG was positively associated and SB event‐related EMG was negatively associated with pain intensity ratings (0–10 numerical scale) on post‐sleep waking. These data provide the foundation for a new focus on small, but persistent, elevations in sleep EMG activity over the course of the night as a mechanism of pain induction or maintenance.     

Functional reconstruction and evaluation of oral cavity: flap design and guideline

The radial forearm free flap is a useful reconstructive method of surgical defects after oral and oropharyngeal tumor resection. We evaluated the swallowing and speech outcomes of radial forearm free flap reconstruction for oral and oropharyngeal cancers.     

Raloxifene therapy inhibits osteoclastogenesis during the alveolar healing process in rats

Objective

To investigate the expression of OPG, RANKL and TRAP during alveolar healing process (7, 14, 21, 28 and 42 postoperative days) in ovariectomized rats treated with raloxifene or with oestrogen replacement therapy, using immunohistochemistry reaction approach.

Materials and methods

Wistar female rats (10 weeks age) were submitted to ovariectomy surgery (OVX) or sham surgery. The female rats were divided in four groups: (1) sham; (2) OVX/O (ovariectomy and oil); (3) OVX/E2 (ovariectomy and oestrogen replacement); (4) OVX/RLX (ovariectomy and raloxifene therapy).

Results

It was observed high amount of OPG immunolabelling with predominance at 14 and 21 postoperative days on sham and OVX/RLX groups, respectively. At 7 postoperative days, there was no difference between the groups for TRAP protein. Otherwise, to the other periods, it was observed greater expression of TRAP and RANKL protein on OVX/O group compared to sham, OVX/E2 and OVX/RLX groups. It was also observed a discrete TRAP immunolabelling at 28 and 42 postoperative days on OVX/RLX group.

Conclusions

Oestrogen deficiency induces osteoclastogenesis in the alveolar healing process. Quantitative changes in the osteoclastic activity could be prevented through the raloxifene therapy.