In situ randomised trial investigating abrasive effects of two desensitising toothpastes on dentine with acidic challenge prior to brushing

Objectives

To determine if brushing dentine with 2 moderate RDA desensitising toothpastes, results in a significant dentine wear difference and whether this difference continues to be relevant when preceded with an erosive challenge.

Methods

An in situ, single centre, single blind, randomised, split mouth study, evaluated the difference in abrasion of 2 toothpastes (SFM - Sensodyne Fresh Mint^® RDA 70; CPHM - Crest Pro-Health Clean Mint^® RDA 120) in 28 healthy volunteers. Two toothpaste treatments were administered 3×/day, for each of the two 15 day periods, subjects wearing bi-lateral, lower buccal appliances each with 4 dentine sections. A 2 min extra-oral acidic challenge preceded toothbrushing for 2 study arms. Contact profilometry measured samples at baseline, days 5, 10 and 15.

Results

Brushing with SFM was significantly less abrasive than brushing with CPHM at all time points, with or without a preceding acidic challenge (p < 0.0001). The additional dentine loss arising from the erosive challenge prior to brushing with each paste was linear with time and independent of abrasive effect.

Conclusions

The desensiting toothpastes’ RDA, directly related to dentine loss with toothbrushing. An acidic challenge prior to brushing did not negate the benefits of reduced wear from the lower RDA paste compared to the higher RDA paste. When brushing eroded dentine, the additional wear appeared independent of abrasive effect. Dentine hypersensitivity sufferers should be recommended to use a low-moderate RDA toothpaste, not to brush more than 2×/day and not immediately following an acidic challenge.     

Induction of apoptosis in oral epithelial cells by Candida albicans

During infection, interactions between Candida albicans and oral epithelial cells result in oral epithelial cell death. This is clinically manifested by the development of oral mucosal ulcerations generally associated with discomfort. In vitro studies have shown that C. albicans induces early apoptotic alterations in oral epithelial cells; however, these studies have also shown that treatment of infected cells with caspase inhibitors does not prevent their death. The reasons for these contradictory results are unknown and it is still not clear if C. albicans stimulates oral epithelial signaling pathways that promote apoptotic cell death. Activation of specific death pathways in response to microbial organisms plays an essential role in modulating the pathogenesis of a variety of infectious diseases. The aim of this study was to (i) characterize C. albicans‐induced apoptotic morphological alterations in oral epithelial cells, and (ii) investigate the activation of apoptotic signaling pathways and expression of apoptotic genes during infection. Candida albicans induced early apoptotic changes in over 50% of oral epithelial cells. However, only 15% of those showed mid‐late apoptotic alterations. At the molecular level, C. albicans caused a loss of the mitochondrial transmembrane potential and translocation of mitochondrial cytochrome c. Caspase‐3/9 activities increased only during the first hours of infection. Moreover, poly[ADP ribose] polymerase 1 was cleaved into apoptotic and necrotic‐like fragments. Finally, five anti‐apoptotic genes were significantly upregulated and two pro‐apoptotic genes were downregulated during infection. Altogether, these findings indicate that epithelial apoptotic pathways are activated in response to C. albicans, but fail to progress and promote apoptotic cell death.     

Antibiotic effects on bacterial profile in osteonecrosis of the jaw

Oral Diseases (2011) 18 , 85–95 Objective: Oral infection is considered to play a critical role in the pathogenesis of bisphosphonate‐related osteonecrosis of the jaw (BRONJ), and antibiotic therapy has become a mainstay of BRONJ therapy. This study was aimed to investigate the effect of antibiotics on bacterial diversity in BRONJ tissues. Materials and methods: The bacterial profile from soft tissues associated with the BRONJ lesion was determined using 16S rRNA‐based denaturing gradient gel electrophoresis (DGGE) and sequencing. Twenty BRONJ subjects classified as stage 0–2 were enrolled in this study, and patient groups were divided into an antibiotic cohort (n = 10) treated with systemic antibiotic and a non‐antibiotic cohort (n = 10) with no prior antibiotic therapy. Results: The DGGE fingerprints indicated no significant differences in bacterial diversity of BRONJ tissue samples. Patients on antibiotics had higher relative abundance of phylum Firmicutes with bacterial species, Streptococcus intermedius, Lactobacillus gasseri, Mogibacterium timidum, and Solobacterium moorei, whereas patients without antibiotics had greater amounts of Parvimonas micra and Streptococcus anginosus. Thirty percent of bacterial populations were uncultured (yet‐to be cultured) phylotypes. Conclusion: This study using limited sample size indicated that oral antibiotic therapy may have a limited efficacy on the bacterial population associated with BRONJ lesions.     

The effectiveness of cognitive-behavioural therapy for temporomandibular disorders: a systematic review

Cognitive-behavioural therapy (CBT) and its effects on temporomandibular disorders (TMD) have been examined in several studies. We are trying to combine results of these studies and to explore the effectiveness. MEDLINE, EMBASE, Cochrane Central Register of Controlled Trial, Pubmed and the Chinese Biomedical Literature Data were searched to collect randomised and semi-randomised controlled trials (RCTs), comparing CBT with any control group receiving other dental treatments. Two authors independently retrieved, extracted and assessed the quality of included studies. The search strategy resulted in 323 studies, of which five met the inclusion criteria, including three RCTs and two semi-RCTs. The quality of the included studies was diverse. Meta-analysis was not performed owing to five studies involving different comparison groups and follow-up periods. The effect of CBT on patients with TMD is inconsistent among the studies, so no firm conclusion could be drawn in this systematic review. There is insufficient evidence to make firm recommendations for the use of CBT over other intervention for the treatment of TMD. Further high-quality RCTs are clearly needed for this theme.     

即刻种植动物模型的建立及意义

为建立与临床即刻种植相符的动物模型,采用去骨法扩大犬下颌前磨牙新鲜拔牙创和种植直径２ｍｍ自攻螺纹式纯钛种植体,对以往即刻种植动物实验模型加以改进,使种植体植入后其近中留有３ｍｍ×３ｍｍ×５ｍｍ的骨缺损区,设计为异体脱钙冻干骨粒（ＤＦＤＢＡ）植入组和对照组,于术后２周、４周、８周、１２周取材观察骨缺损愈合情况。结果,ＤＦＤＢＡ植入组１２周骨缺损为新骨替代,对照组骨缺损仅修复３／５。该模型制作简便、制模时间短、接近临床,是一种较好的用于即刻种植研究的动物模型     

Nonlinear spectral imaging of human hypertrophic scar based on two-photon excited fluorescence and second-harmonic generation

Background A noninvasive method using microscopy and spectroscopy for analysing the morphology of collagen and elastin and their biochemical variations in skin tissue will enable better understanding of the pathophysiology of hypertrophic scars and facilitate improved clinical management and treatment of this disease. Objective To obtain simultaneously microscopic images and spectra of collagen and elastin fibres in ex vivo skin tissues (normal skin and hypertrophic scar) using a nonlinear spectral imaging method, and to compare the morphological structure and spectral characteristics of collagen and elastin fibres in hypertrophic scar tissues with those of normal skin, to determine whether this approach has potential for in vivo assessment of the pathophysiology of human hypertrophic scars and for monitoring treatment responses as well as for tracking the process of development of hypertrophic scars in clinic. Methods Ex vivo human skin specimens obtained from six patients aged from 10 to 50 years old who were undergoing skin plastic surgery were examined. Five patients had hypertrophic scar lesions and one patient had no scar lesion before we obtained his skin specimen. A total of 30 tissue section samples of 30 μm thickness were analysed by the use of a nonlinear spectral imaging system consisting of a femtosecond excitation light source, a high‐throughput scanning inverted microscope, and a spectral imaging detection system. The high‐contrast and high‐resolution second harmonic generation (SHG) images of collagen and two‐photon excited fluorescence (TPEF) images of elastin fibres in hypertrophic scar tissues and normal skin were acquired using the extracting channel tool of the system. The emission spectra were analysed using the image‐guided spectral analysis method. The depth‐dependent decay constant of the SHG signal and the image texture characteristics of hypertrophic scar tissue and normal skin were used to quantitatively assess the amount, distribution and orientation of their collagen and elastin components. Results Our experiments and data analyses demonstrated apparent differences between hypertrophic scar tissue and normal skin in terms of their morphological structure and the spectral characteristics of collagen and elastin fibres. These differences can potentially be used to distinguish hypertrophic scar tissues from normal skin and to evaluate treatment responses. Conclusions All the measurements were performed in backscattering geometry and demonstrated that nonlinear spectral imaging has the ability to differentiate hypertrophic scar tissue from normal skin based on noninvasive SHG imaging, and TPEF imaging revealed the microstructure and spectral features of collagenand elastin fibres. With the advances in spectral imaging apparatus miniaturization, we have good reason to believe that this approach can become a valuable tool for the in vivo pathophysiology study of human skin hypertrophic scars and for assessing the treatment responses of this disfiguring disease in clinic. It can also be used to track the development of hypertrophic scars and to study wound healing processes in a noninvasive fashion without biopsy, fixation, sectioning and the use of exogenous dyes or stains.     

Clinicopathological characteristics, management and outcome of metastatic penoscrotal extramammary Paget's disease

Background  Metastatic penoscrotal extramammary Paget's disease (EMPD) has seldom been reported in the literature.
Objectives  To improve the knowledge of the clinicopathological characteristics, management and outcome in patients with this disease.
Methods  The medical records and pathological slides of 10 patients with metastatic EMPD and 33 patients with nonmetastatic disease were reviewed. Immunohistochemical staining for epithelial cadherin (E-cadherin) was performed in the primary skin disease. All the 10 patients received 5-fluorouracil- or docetaxel-based chemotherapy.
Results  The most common sites of metastases were lymph nodes followed by bone. Patients with metastatic EMPD were more likely to be young and had elevated carcinoembryonic antigen (CEA) levels. Dermal or deeper invasion, lymphovascular embolization and negative expression of E-cadherin were important pathological predictors of metastatic potential. In invasive EMPD, lymphovascular embolization but not expression of E-cadherin was significantly associated with the risk of metastases. In three patients, ¹⁸F-fluorodeoxyglucose positron emission tomography (PET)–computed tomography (CT) scans revealed occult lymph node metastases which were overlooked at conventional CT examinations. Two patients had complete response to the chemotherapy, three had partial response and five had progressive disease. The 2-year overall survival rate was 48% in patients with metastatic EMPD. In those patients with significantly elevated CEA level, the value of CEA paralleled the disease course.
Conclusions  Metastatic EMPD tended to have dermal invasion and lymphovascular embolization. PET–CT scans were helpful in detecting distant metastases. 5-Fluorouracil- or docetaxel based-chemotherapy was effective in some patients. Serum CEA level can be a useful biomarker for monitoring disease course.     

Retinal vein occlusions and mortality: the Beijing Eye Study

PURPOSE: To assess the association between retinal vein occlusion (RVO) and mortality in a population-based setting. DESIGN: Population-based, longitudinal study. METHODS: At baseline in 2001, the Beijing Eye Study examined 4,335 subjects for RVO with a frequency of detected vein occlusions of 61 (1.4%) in 4,335 subjects. In 2006, all study participants were invited for a follow-up examination. RESULTS: Of the 4,335 subjects, 3,195 (73.7%) returned for follow-up examination, whereas 132 (3.0%) subjects had died and 1,008 (23.3%) subjects declined to be re-examined or had moved away. For the subjects younger than 70 years or than 65 years, respectively, RVO was associated significantly with an increased mortality rate (P = .05; 95% confidence interval [CI], 0.995 to 8.26; and P = .001; 95% CI, 2.11 to 18.73, respectively). CONCLUSIONS: RVO in relatively young persons may signal a significant risk of mortality.     

Underdevelopment of optic radiation in children with amblyopia: a tractography study

PURPOSE: To detect the abnormalities of the optic radiation (OR) in children with amblyopia by diffusion tensor imaging (DTI) and tractography. DESIGN: Prospective, nonrandomized clinical trial. METHODS: Fourteen children with amblyopia and 14 normally sighted children underwent DTI scanning. After the ORs were reconstructed by using tractography algorithm, voxels through which the anterior parts of ORs passed were determined for their values of fractional anisotropy (FA). The paired t test was applied to compare their mean FA values of right OR and left OR in the control group. For the amblyopia group, analysis of variance was conducted to determine the effect of laterality and vision status on the FA values. In addition, the voxel numbers of anterior and posterior parts of both ORs were calculated. The Student t test was used to compare the average FA of bilateral ORs and voxel numbers between the two groups. RESULTS: Comparison demonstrated left-higher-than-right asymmetry in both amblyopic children and normal children. We found no significant difference of average FA between the amblyopic group (0.4832 +/- 0.0225) and control group (0.4770 +/- 0.0273). Voxel numbers of the anterior parts of both ORs were not significantly different between the two groups, whereas voxel numbers of their posterior parts in the controls were more than that of amblyopic children. CONCLUSION: Tractography showed more voxels in the posterior ORs of normal children than in the amblyopic children, indicating that normal children have better development of the ORs. The underdevelopment of the ORs might reflect the dysfunction of visual cortex in children with amblyopia.