Is titanium alloy Ti-6Al-4 V cytotoxic to gingival fibroblasts-A systematic review.

OBJECTIVES: Grade V titanium alloy (Ti-6Al-4 V) is a well-recognized metallic biomaterial for medical implants. There has been some controversy regarding the use of this alloy in medical devices in relation to the toxicity of vanadium. In Dentistry, Ti-6Al-4 V remains prevalent. This systematic review aims to evaluate the effects of Ti-6Al-4 V on cells relevant to oral environments such as gingival fibroblasts. MATERIALS AND METHODS: A literature search was undertaken for relevant English language publications in the following databases: Dental and Oral Science, Medline and Web of Science. The electronic search was supplemented with a search of references. RESULTS: After application of inclusion and exclusion criteria. A total of eight papers are included in this review. These papers were all in vitro studies and were categorized into whole implant, discs, or implant particles based on the type of test materials used in the studies. CONCLUSION: Based on the analyses of the eight included studies in this review, if Ti-6Al-4 V as a material is unchallenged, i.e., as a whole implant in pH neutral environments, there appears to be little effect on fibroblasts. If Ti-6Al-4 V is challenged through corrosion or wear (particle release), the subsequent release of vanadium and aluminium particles has an increased cytotoxic effect in vitro in comparison to commercially pure titanium, hence concerns should be raised in the clinical setting.

Chronic Porphyromonas gingivalis infection accelerates the occurrence of age-related granules in ApoE-/- mice brains.

This study explored the origin of age-related granules in the apolipoprotein E gene knockout (ApoE-/-) B6 background mice brains following chronic gingival infection with Porphyromonas gingivalis for 24 weeks. Intracerebral localization of P. gingivalis was detected by fluorescence in situ hybridization (FISH) and its protease by immunohistochemistry. The age-related granules were observed by periodic acid-Schiff (PAS), silver impregnation, and immunostaining. FISH showed intracerebral dissemination of P. gingivalis cells (p = 0.001). PAS and silver impregnation demonstrated the presence of larger inclusions restricted to the CA1, CA2, and dentate gyrus sectors of the hippocampus. A specific monoclonal antibody to bacterial peptidoglycan detected clusters of granules with variable sizes in mice brains infected with P. gingivalis (p = 0.004), and also highlighted areas of diffuse punctate staining equating to physical tissue damage. Mouse immunoglobulin G was observed in the capillaries of the cerebral parenchyma of all P. gingivalis-infected brains (p = 0.001), and on pyramidal neurons in some severely affected mice, compared with the sham-infected mice. Gingipains was also observed in microvessels of the hippocampus in the infected mice. This study supports the possibility of early appearance of age-related granules in ApoE-/- mice following inflammation-mediated tissue injury, accompanied by loss of cerebral blood-brain barrier integrity.

Developing an ecologically relevant heterogeneous biofilm model for dental-unit waterlines.

This study monitored the biodiversity of microbes cultured from a heterogeneous biofilm which had formed on the lumen of a section of dental waterline tubing over a period of 910 days. By day 2 bacterial counts on the outlet-water showed that contamination of the system had occurred. After 14 days, a biofilm comparable to that of clinical waterlines, consisting of bacteria, fungi and amoebae had formed. This showed that the proprietary silver coating applied to the luminal surface of the commercial waterline tubing failed to prevent biofilm formation. Molecular barcoding of isolated culturable microorganisms showed some degree of the diversity of taxa in the biofilm, including the opportunistic pathogen Legionella pneumophila. Whilst the system used for isolation and identification of contaminating microorganisms may underestimate the diversity of organisms in the biofilm, their similarity to those found in the clinical environment makes this a promising test-bed for future biocide testing.

Monitoring dental-unit-water-line output water by current in-office test kits.

The importance of monitoring contamination levels in the output water of dental-unit-water-lines (DUWLs) is essential as they are prone to developing biofilms that may contaminate water that is used to treat patients, with opportunistic pathogens such as species of Legionella, Pseudomonas and others. Dentists and practice staff are also at risk of being infected by means of cross-infection due to aerosols generated from DUWL water. The unit of measurement for the microbial contamination of water by aerobic mesophilic heterotrophic bacteria is the colony-forming unit per millilitre (cfu/ml) of water. The UK has its own guidelines set by the Department of Health for water discharged from DUWL to be between 100 and 200 cfu/ml of water. The benchmark or accepted standard laboratory test is by microbiological culture on R2A agar plates. However, this is costly and not convenient for routine testing in dental practices. A number of commercial indicator tests are used in dental surgeries, but they were not developed for the dental market and serve only to indicate gross levels of contamination when used outside of the manufacturer's recommended incubation period. The aim of this article is to briefly review the universal problem of DUWL contamination with microbial biofilms and to update dental professionals on the availability of currently available commercial in-office monitoring systems for aerobic mesophilic heterotrophic bacteria and to discuss their limitations for testing water samples in assuring compliance with recommended guidelines.

Stability of parenteral nanoemulsions loaded with paclitaxel: the influence of lipid phase composition, drug concentration and storage temperature.

Paclitaxel was loaded into licensed parenteral nutrition nanoemulsions (Clinoleic® and Intralipid®) using bath sonication, and the stability of the formulations was investigated following storage for two weeks at room temperature or at 4 °C. In general, Clinoleic droplets were smaller than Intralipid droplets, being around 255 and 285 nm, respectively, for blank and freshly loaded emulsions. Regardless of storage temperature, the Clinoleic exhibited a very slight or no increase in droplet size upon storage, whilst the droplet size of the Intralipid emulsion increased significantly. The droplet size of both emulsions was minimally affected by paclitaxel concentration within the range of 0, 1, 3 and 6 mg/ml. The pH of both emulsions markedly decreased upon storage at room temperature, which was possibly attributed to the production of fatty acids resulting from phospholipid hydrolysis. However, at 4 °C, the pH of Clinoleic emulsion was unaffected by storage or paclitaxel concentration while the Intralipid emulsion demonstrated a trend for pH reduction. Both nanoemulsions had a negative zeta potential, with the Clinoleic formulations having the highest charge, possibly explaining the better size stability of this emulsion. Overall, this study has shown that paclitaxel was successfully loaded into clinically licensed parenteral emulsions and that Clinoleic showed greater stability than the Intralipid.

Osteogenic potential of bone marrow stromal cells on smooth, roughened, and tricalcium phosphate-modified titanium alloy surfaces.

PURPOSE: This study investigated the influence of smooth, roughened, and tricalcium phosphate (TCP)-coated roughened titanium-aluminum-vanadium (Ti-6Al-4V) surfaces on the osteogenic potential of rat bone marrow stromal cells (BMSCs). METHODS: Machined smooth (MS), grit-blasted roughened (MT), and roughened surfaces coated with TCP were prepared from Ti-6Al-4V. Plastic surfaces were used as a control. Surface topography and chemical characteristics were determined. Cell attachment, morphology, proliferation, and temporal expression of mRNA and protein markers associated with bone healing were examined. RESULTS: Roughness values were 0.09 ± 0.02 Μm, 2.71 ± 0.24 Μm, and 6.08 ± 0.62 Μm for MS, MT, and TCP, respectively. Cell attachment was similar on all surfaces. The cell expansion phase occurred during days 1 to 3 on MS surfaces and days 3 to 5 on MT and TCP surfaces. The earlier onset of differentiation on MS surfaces versus MT and TCP surfaces was evidenced by: high mRNA expression peak for Runx2 at day 5 on MS (day 7 on MT and TCP); higher mRNA expression for osteopontin, osteonectin, bone sialoprotein (BSP), osteocalcin, type 1 collagen, and alkaline phosphatase over days 5 to 12 on MS compared with MT and TCP; higher levels of bone matrix proteins on MS compared with MT, with only BSP detected on TCP; cell morphology consistent with descriptions of differentiating osteoblasts apparent at day 5 on MS and absent on MT. Compared to plastic surfaces, Ti-6Al-4V appeared to suppress mRNA for interleukin 1Β, tumor necrosis factor alpha, and peroxisome proliferator-activated receptor gamma expression and upregulate osteoprotegerin. CONCLUSIONS: Cell expansion was delayed on roughened Ti-6Al-4V surfaces, impeding osteoblast differentiation and bone matrix synthesis. These results disagree with a number of published studies examining pure titanium. Ti-6Al-4V surfaces appear to assist in the resolution of proinflammatory cytokines and inhibit BMSC differentiation toward adipocytes.

In vivo monitoring of the bone healing process around different titanium alloy implant surfaces placed into fresh extraction sockets.

OBJECTIVES: Increasing surface roughness and coating with tricalcium phosphate of titanium and titanium alloy implants has been proposed to provide better rates of osseointegration. However, how these changes in surface topography and chemistry influence the osseointegration process of immediate implants placed in fresh extraction sockets is unclear. This study investigated the influence of three clinically employed implant surfaces on the early bone healing events in vivo. METHODS: Machined smooth implants were milled from grade 5 Ti6Al4V titanium. Surfaces were moderately roughened by grit blasting, which were then coated with tricalcium phosphate. Implants were placed into freshly extracted incisor sockets of mandibles of normal Wistar rats and left for 1, 3 and 9 weeks. Healing bone tissue around the implants was examined by histochemistry and immunocytochemistry to localise PCNA proliferative cells, and osteoblast differentiation markers osteopontin and osteocalcin. Positive synthesising cells were counted using image analysis. RESULTS: Histology indicated no differences in the amount or pattern of bone formation within the healing tissue surrounding the different implant surfaces. Bone healing occurred predominantly on exposed bone surfaces (distance osteogenesis) and not on the implant surface (contact osteogenesis). No differences were observed in the number or timing of PCNA, osteopontin and osteocalcin positive cells within the bone healing tissue around each of the implant analysed. CONCLUSION: For immediately placed implants, the surface modifications investigated appeared to have little influence on the activity of bone forming cells surrounding the implant, probably due to the high level of distance osteogenesis seen within this scenario. CLINICAL SIGNIFICANCE: For immediate placement of implants into fresh extraction sockets, titanium implants with roughened surfaces and coating with tricalcium phosphate have negligible influence in accelerating the early bone healing events of osseointegration.

Delayed osteoblast differentiation and altered inflammatory response around implants placed in incisor sockets of type 2 diabetic rats.

OBJECTIVE: Central to the process of osseointegration is the recruitment of mesenchymal progenitor cells to the healing site, their proliferation and differentiation to bone synthesising osteoblasts. The process is under the control of pro-inflammatory cytokines and growth factors. The aim of this study was to monitor these key stages of osseointegration and the signalling milieu during bone healing around implants placed in healthy and diabetic bone. METHODS: Implants were placed into the sockets of incisors extracted from the mandibles of normal Wistar and diabetic Goto-Kakizaki rats. Mandibles 1-12 weeks post-insertion of the implant were examined by histochemistry and immunocytochemistry to localise the presence of Stro-1- positive mesenchymal progenitor cells, proliferating cellular nuclear antigen proliferative cells, osteopontin and osteocalcin, macrophages, pro-inflammatory cytokines interleukin (IL)-1ß, IL-6, tumour necrosis factor (TNF)-α and tumour growth factor (TGF)-ß1. Image analysis provided a semi-quantification of positively expressing cells. RESULTS: Histological staining identified a delay in the formation of mineralised bone around implants placed in diabetic animals. Within the diabetic bone, the migration of Stro-1 mesenchymal cells in the healing tissue appeared to be unaffected. However, in the diabetic healing bone, the onset of cell proliferation and osteoblast differentiation were delayed and subsequently prolonged compared with normal bone. Similar patterns of change were observed in diabetic bone for the presence of IL-1ß, TNF-α, macrophages and TGF-ß1. CONCLUSION: The observed alterations in the extracellular presence of pro-inflammatory cytokines, macrophages and growth factors within diabetic tissues that correlate to changes in the signalling milieu, may affect the proliferation and differentiation of mesenchymal progenitor cells in the osseointegration process.

Is there a relationship between birthweight and subsequent growth on the development of dental caries at 5 years of age? A cohort study.

OBJECTIVES: To examine the associations between childhood growth and the presence of dental caries at age 5. METHODS: Data from the Avon Longitudinal Study of Parents and Children (ALSPAC) a population-based, prospective cohort study were used. We enrolled 14,541 pregnancies, and a 10% sample of these were dentally examined and measured at 61 months of age. Birthweight was obtained from medical records, and birth length and birthweight were assessed by trained ALSPAC measurers. A number of social and lifestyle factors were treated as potential confounding factors. RESULTS: Of 985, children, 242 (24.6%) had caries at 61 months of age. After adjustment, increased weight at birth was associated with a small increased risk of caries at 61 months (OR: 1.08 (95% CI: 1.03, 1.13) per 100 g increase, P = 0.002). A similar association was noted with respect to increased length at birth. Current weight and height did not appear to be associated with caries risk. Children who had caries at 61 months had slower increases in weight and height between birth and 61 months than those without decay at 61 months. CONCLUSIONS: The weak associations we have demonstrated between weight and length at birth and risk of caries at age 61 months cannot be considered causal, however, the relationship between the two variables warrants further investigation.

Exploring the link between microorganisms and oral cancer: a systematic review of the literature.

The majority of cases of oral cancer have been related to tobacco use and heavy alcohol consumption. However, the incidence of oral cavity carcinoma appears to be increasing in many parts of the world in a manner that it is difficult to explain with traditional risk factors alone. Meanwhile, interest in the possible relationships between microorganisms and the different stages of cancer development has been rising and numerous mechanisms by which bacteria and yeast may initiate or promote carcinogenesis are currently under investigation. In particular, a persuasive body of evidence suggests a possible etiological role involving the metabolism and production of carcinogenic products, such as acetaldehyde. Other suggested mechanisms include the induction of chronic inflammation and direct interference with eukaryotic cell cycle and signaling pathways. This review aims to summarize the known associations between microbial infection and cancer and draw attention to how they may relate to oral carcinoma.

IGF-I protects human oral buccal mucosal epithelial cells from sodium nitroprusside-induced apoptosis via PI3-kinase.

OBJECTIVE: Cancers of the head and neck account for the vast majority of all malignancies of the oral cavity. The insulin-like growth factor (IGF) family of proteins is well documented to have an important role in rescuing cells from apoptosis. While it is known the IGF proteins are present in normal oral epithelial and cancer cells its role is not fully understood. Our aim was to study the ability of IGFs to rescue sodium nitroprusside (SNP)-induced apoptotic normal oral epithelial cells in vitro. DESIGN: Cultured normal human oral keratinocytes (NOKs) or epithelial cells were used. Apoptosis was induced by SNP then cells were exposed to IGF-I or IGF-II to rescue them. Cell viability was assessed by ELISA (for cell death and caspase 3) and FACS analysis; post receptor effects of IGF-I or IGF-II were assessed by [(3)H] thymidine incorporation. Cell signaling events were measured by western blotting using antibodies against phosphorylated Akt or p42/p44 MAPK, and measuring PI3-K activity by ELISA. RESULTS: SNP induced apoptosis of NOKs and activated the PI3-K/Akt survival pathway. Exposing cells to IGF proteins prevented their apoptosis. IGF-I and -II caused significant increases in PI3-K, but not MAPK, activity. SNP and LY294002, a PI3-K inhibitor, both caused a significant rise in caspase 3 release from NOKs which was reduced in the presence of IGFs. CONCLUSIONS: The data establishes the importance of IGF-activated PI3-K in rescuing cells from apoptosis. It lends further evidence to the significance of IGF proteins in the possible development of oral cancer.

A molecular analysis of the bacteria present within oral squamous cell carcinoma.

In order to characterize the bacterial microbiota present within oral cancerous lesions, tumorous and non-tumorous mucosal tissue specimens (approx. 1 cm(3)) were harvested from ten oral squamous cell carcinoma (OSCC) patients at the time of surgery. Any microbial contamination on the surface of the specimens was eliminated by immersion in Betadine and washing with PBS. Bacteria were visualized within sections of the OSCC by performing fluorescent in situ hybridization with the universal oligonucleotide probe, EUB338. DNA was extracted from each aseptically macerated tissue specimen using a commercial kit. This was then used as template for PCR with three sets of primers, targeting the 16S rRNA genes of Spirochaetes, Bacteroidetes and the domain Bacteria. PCR products were differentiated by TA cloning and bacterial species were identified by partial sequencing of the 16S rRNA gene fragments. A total of 70 distinct taxa was detected: 52 different phylotypes isolated from the tumorous tissues, and 37 taxa from within the non-tumorous specimens. Differences between the composition of the microbiotas within the tumorous and non-tumorous mucosae were apparent, possibly indicating selective growth of bacteria within carcinoma tissue. Most taxa isolated from within the tumour tissue represented saccharolytic and aciduric species. Whether the presence of these bacteria within the mucosa has any bearing on the carcinogenic process is a concept worthy of further investigation.

Upregulation of IGF-2 and IGF-1 receptor expression in oral cancer cell lines.

The insulin-like growth factors (IGFs) are a family of mitogenic proteins involved in the regulation of cell growth and differentiation. The presence and role of the IGF system in oral mucosal epithelium is not clear but could influence our understanding of the pathogenesis of oral cancer. We characterised the expression and function of IGF-1, IGF-2 and IGF receptor in human oral squamous carcinoma cell lines and normal oral epithelial cells as well as normal oral and squamous cell carcinoma tissues. Using reverse transcription followed by PCR, IGF-1 mRNA was only detected in normal cells, whereas IGF-2 and IGF-1R mRNA transcripts were highly expressed in tumour cell lines and tissues. Similar observations were seen by Western blot analysis and immunohistochemistry. Exogenous IGF-2, but not IGF-1, caused significant increases in DNA synthesis in the cell lines. IGF-2 also increased cell proliferation which was significantly attenuated in the presence of an IGF-2 neutralizing antibody or one which blocked IGF-1R. Taken together, these studies suggest that autocrine production of IGF-2, together with over-expression of IGF-1R, may be important components controlling the proliferation of oral carcinoma cells.

Recurrent Kikuchi-Fujimoto disease: case report.

Kikuchi-Fujimoto disease, also known as histiocytic necrotising lymphadenitis, is a self-limiting condition of uncertain aetiology characterised by lymphadenopathy, pyrexia, and neutropenia. Some reported cases have been associated with systemic lupus erythematosus and there have been suggestions that Kikuchi's disease could represent a mild form of lupus but without definite evidence. We describe an unusual case of histiocytic necrotising lymphadenitis in an Asian woman who had recurrent episodes for five years before a diagnosis was made.

Viable bacteria present within oral squamous cell carcinoma tissue.

Despite increasing interest in the possible relationships between bacteria and the different stages of cancer development, the association of bacteria with cancer of the oral cavity has yet to be adequately examined. With that in mind, the primary objective of this study was to identify any bacterial species within oral squamous cell carcinoma tissue using a standard microbiological culture approach. At the time of surgery, a 1-cm3 portion of tissue was harvested from deep within the tumor mass using a fresh blade for each cut. Whenever possible, "superficial" portions from the mucosa overlying the tumor and nontumorous control specimens from at least 5 cm away from the primary tumor site were also obtained. Surface contamination was eliminated by immersion in Betadine and washing with phosphate-buffered saline. Each specimen was aseptically macerated and cultured on nonselective media under both aerobic and anaerobic conditions. Isolates were identified by 16S rRNA gene sequencing. Twenty deep-tissue specimens, 19 with corresponding superficial tissues and 12 with control tissues, were successfully processed. A diversity of bacterial taxa were isolated and identified, including several putatively novel species. Most isolates were found to be saccharolytic and acid-tolerant species. Notably, some species were isolated only from either the tumorous or nontumorous tissue type, indicating a degree of restriction. Successful surface decontamination of the specimens indicates that the bacteria detected were from within the tissue. A diversity of bacterial groups have been isolated from within oral squamous cell carcinoma tissue. The significance of these bacteria within the tumor warrants further study.

Eyebrow reconstruction using composite graft and microsurgical transplant.

The pivotal role that eyebrows play in facial expression and aesthetics is widely accepted, along with the difficulties faced by surgeons in reconstructing defects in this area. The case study presented demonstrates reconstruction of a traumatic eyebrow defect using a post-auricular composite graft in combination with a microfollicular hair transplant technique. The advantage of the combined approach is discussed with reference to the fine tuning of the adjoining areas between reconstructed and undamaged hair-bearing regions. The advantages of this technique in control of the direction of hair growth and preservation of hair density are emphasised.

Eosinophilic granuloma: resolution of maxillofacial bony lesions following minimal intervention. Report of three cases and a review of the literature.

INTRODUCTION: Langerhans' cell histiocytosis is a collective term used to describe a group of enigmatic proliferative disorders. The natural history of the disease varies from a slow, benign, localized symptomatic bony or soft tissue lesion, to a rapidly progressive widespread multiple organ disorder which is often fatal. Eosinophilic granuloma accounts for 60-70% of all cases of Langerhans' cell histiocytosis and can present as solitary (50-75%) or multifocal defects in bone. It occasionally presents as a localized soft tissue lesion. There are multiple treatment options but the response is unpredictable. AIMS: We present three separate cases, of the maxillofacial skeleton where the lesions of eosinophilic granuloma resolved following incisional biopsy only. PATIENTS AND RESULTS: Three patients presented with solitary lesions of the maxillofacial skeleton. All were diagnosed as Langerhans' cell histiocytosis following open curettage, which also resulted in resolution of the lesions. Follow-up has thus far been disease free. CONCLUSION: For some solitary Langerhans' cell histiocytosis lesions, simple curettage is the only treatment required. The paper discusses the need to confirm the solitary nature of the disease and the need for follow-up. Reviewing the literature on the disease, the authors suggest that perhaps cellular immaturity holds the cells of the lesion in a disease state until pushed to maturity by the trauma of open curettage surgery, resulting in a complete resolution of the disease.

Reduction of occult metastatic disease by extension of the supraomohyoid neck dissection to include level IV.

BACKGROUND: Patients with clinically N0 necks will undergo elective removal of lymphatic tissue from levels I, II, and III as part of their routine surgical management. Level IV is omitted on the basis that there is negligible chance of containing significant occult disease. Evidence to support this approach is minimal, and the aim of this study was to increase the yield of metastatically involved lymph nodes by simply extending the supraomohyoid neck dissection (SOHND) to include level IV. METHODS: The records of 49 patients with cancer of the oral cavity undergoing extended supraomohyoid neck dissection (ESOHND) during the period January 1996-March 1999 were reviewed. All patients were staged as having N0 disease. The follow-up period ranged from 12 to 36 months. RESULTS: Thirteen of 55 N0 stage necks showed occult metastasis (26.5%). Neck failure rate occurred in 4 of 49 patients (8.2%). Neck failure rate in the pN0 group was 5.4% and in the pN+ group was 16.6%. Complication rates of ESOHND were noted as 3.6%. No long-term morbidity arose. Occult metastasis in level IV occurred in 5 of 49 cases (10%). Two cases involved other surgical levels. CONCLUSIONS: ESOHND as performed in this study removed occult level IV metastatic regional disease from an extra 10% of patients that, if the patients had undergone SOHND, would have remained undiscovered. No long-term morbidity is associated with this procedure that the authors now recommend as a first-line treatment in all patients with N0 necks.

Oral pemphigus vulgaris occurring during pregnancy.

There have been few reports describing the occurrence of pemphigus vulgaris (PV) during pregnancy. The patient described in this case report is interesting because the PV that developed during her pregnancy was confined to her mouth. It has been suggested that prompt treatment with systemic steroids prevents development of PV in cutaneous tissues. In this case, early control of the condition is believed to have eliminated the need for high dose steroids throughout the remainder of the pregnancy. In addition, this therapeutic approach could have contributed to the birth of a baby free of PV. Resolution of the presenting oral symptoms allowed the mother to resume a normal diet, allaying her anxiety about the possible effects of poor nutritional intake on foetal development. Aspects of clinical management considered in this report include the choice of immunosuppressive therapy and the multidisciplinary care involving both dental and obstetric specialists.