Retention of Asymptomatic Third Molars May be Unwise.

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION: What is the risk of future extraction of asymptomatic third molars? A systematic review. Bouloux GF, Busaidy KF, Beirne OR, Chuang S-K, Dodson TB. J Oral Maxillofac Surg 2015;73(5):806-11. SOURCE OF FUNDING: No external funding source is identified although all 5 authors appear to be on the American Association of Oral and Maxillofacial Surgery 3rd Molar Task Force TYPE OF STUDY/DESIGN: Systematic review.

Alcohol and mouth cancer.

There is now considered to be no safe limit for alcohol intake. Studies have shown that risk of mouth cancer increases with greater alcohol intake (in particular when associated with the use of tobacco). This paper reviews the role for alcohol in the aetiology of mouth cancer both in terms of how it may give rise to cancerous change and the relative risk it carries (arising from various systematic and meta-analyses reported over the last decade). While obtaining a reliable alcohol history can be problematic (with under reporting frequently suspected) greater awareness of the role of alcohol in both local and systemic disease (in particular that of cancer in an ever increasing number of sites) may serve as a motivator for behaviour change within our patients. To that end patients should be aware of the alcohol content in the drinks they consume and consider recording their alcohol intake over a defined period (eg, use of a diary or app over a two to four week period).

Dyskeratosis congenita.

Dyskeratosis congenita is an inherited disorder that usually presents in males, consisting of the triad of leukoplakia of the mucous membranes, nail dystrophy and skin pigmentation. Whilst most cases are X-linked, autosomal dominant and recessive forms have been reported. The significance of the condition lies in premature mortality arising from either bone marrow failure or malignant change within the areas of leukoplakia. Various mucocutaneous and non-mucocutaneous manifestations have been reported. The syndrome arises from an inherited defect within the DKC1 gene that codes for the protein dyskerin in the X-linked recessive form of the disorder, whereas mutations in the RNA component of telomerase (TERC) result in the autosomal dominant form of the condition. The identification of a white patch within the mouth of a child in the absence of any other obvious cause should arouse suspicion of this rare condition. Greater understanding of the molecular biology surrounding this syndrome should lead to improvements in diagnosis, monitoring of disease progression and therapy.

Vascularity and expression of vascular endothelial growth factor in oral squamous cell carcinoma, resection margins, and nodal metastases.

The role of vascularity as a predictor of the likelihood of lymph node metastases in oral cancer is not clear. To that end, the vascularity and expression of vascular endothelial growth factor (VEGF) was assessed at three specific regions: the tumour (inside and around the tumour); the resection margin; and the regional lymph nodes. Formalin-fixed paraffin-embedded specimens from 26 oral cancers (11 with no involved nodes and 15 with involved nodes) were stained immunohistochemically and examined. Staining for VEFG was significantly greater in the tumour than in the other sites. No significant differences were found in the intensity of staining in the primary tumour, resection margins, or nodes between cases in which the nodes were involved and in which they were not involved. We found no correlation between vascularity and VEGF staining, suggesting that VEGF is not the primary or only stimulator of angiogenesis in oral cancer. Greater understanding of the mechanisms of metastasis will lead to new treatments. The evidence that is accumulating for oral cancer suggests that such treatments may be better targeted at preventing lymphatic spread, rather than vascular spread.

Evidence for a field change effect based on angiogenesis in the oral mucosa? A brief report.

The concept of field cancerisation was proposed to explain the development of second primary tumours in the upper aerodigestive tract. The formation of new blood vessels (angiogenesis) has been shown to accompany oral disease progression, however, little is known about its potential role as an indicator of field cancerisation. The aims of this study were to compare the angiogenic profile of normal oral mucosa from oral cancer patients with that sampled from cancer-free patients to seek evidence for differences that might be termed a field change. Oral mucosal tissue (NC) was obtained from 25 oral cancer patients from a site at least 1 cm distant from the primary tumour and was compared with normal oral mucosa (NN) from a further 20 non-cancer patients. The vascularity of the tissue was investigated immunohistochemically using four antibodies and three methods of quantitation. Vascularity was significantly higher in the NC group than the NN with all four markers (p<0.01). Significantly higher indices of vascularity were found for patients who were smoker/drinkers in the NC group (p<0.05). The increased vascularity may provide a rationale for anti-angiogenic drug therapy for tertiary prevention.

Keratin profiles of normal and malignant oral mucosa using exfoliative cytology.

AIMS: To assess keratin profiles from smears of malignant and contralateral normal oral mucosa as part of the development of a screening procedure for oral cancer based on exfoliative cytology. METHODS: Smears were taken from oral cancers (confirmed by biopsy) and from the contralateral site of 20 patients. Using a panel of antikeratin antibodies, the keratins expressed by these cells were identified using a standard immunocytochemical technique (Vectastain) and assessed on a 3 point scale. RESULTS: Using chi 2 analysis, noticeable differences between the keratin profiles for malignant mucosal smears compared with the contralateral mucosal smears were found. This was particularly evident for the simple epithelial keratins. CONCLUSION: Individual keratins can be identified in smears from oral cancers. The identification of simple epithelial keratins seem to be the best keratin markers associated with malignancy. Their detection within smears from oral lesions could be valuable in the early diagnosis of oral cancer.

Effect of radiotherapy on oral mucosa assessed by quantitative exfoliative cytology.

The effect of radiotherapy on normal buccal mucosa was investigated using the quantitative techniques of cytomorphology (measurement of nuclear and cytoplasmic area) and DNA cytophotometry. These techniques were applied to smears obtained before, during, and after irradiation. Nuclear area and cytoplasmic area increased and DNA values were abnormal in most cases as a result of radiotherapy, returning to within normal limits one month after treatment. This contrasts strongly with the changes seen in smears from previously irradiated uterine cervices, where changes in cytomorphology may persist for several years.

p53 expression in dyskeratosis congenita: a marker for oral premalignancy?

As p53 expression has been associated with malignant disease its presence was assessed in biopsy specimens from dorsal lingual hyperkeratosis, taken over a five year period. p53 expression, using CM1, was assessed using a standard immunoperoxidase technique. p53 was not identified in the first biopsy specimen in 1986 but was identified in all subsequent ones. Only in the latest biopsy specimen was there evidence for dysplasia in haematoxylin and eosin stained sections. It is suggested that p53 expression may be a reliable marker for predicting premalignant change in keratoses occurring in dyskeratosis congenita.

p53 protein in odontogenic cysts: increased expression in some odontogenic keratocysts.

AIMS: To assess p53 protein expression in a range of odontogenic cysts arising in the mouth, including those of developmental and inflammatory origin. METHODS: p53 protein was identified using the polyclonal antibody CM-1, together with a standard immunoperoxidase technique. A total of 36 cystic lesions were examined, all of which were histologically benign. RESULTS: Expression of p53 protein was identified within the lining of five of 12 odontogenic keratocysts but was not detected in the other cystic lesions in the series. CONCLUSIONS: This is believed to be the first report that identifies increased expression of p53 protein in benign cystic epithelium. The increased expression of p53 protein in the nucleus is usually associated with malignant disease. These findings are relevant to the management of odontogenic keratocysts which have a tendency to recur, and also to Gorlin Goltz syndrome in which keratocysts and multiple basal cell carcinomas are features.

Cell deletion by apoptosis during regression of rat parotid sialadenosis.

Enlargement of the rat parotid salivary glands was induced by repeated administration of isoproterenol. Mean wet weights of the treated glands increased steadily to 240% of control values. Following withdrawal of the drug, quantitative histological techniques were used to investigate the balance between hypertrophy, hyperplasia and apoptosis. The volume occupied by acinar cells relative to the total gland volume together with cytoplasmic magnitude of nuclear area ratios as measures of hypertrophy increased during the early experimental period. Similarly, serous acinar cell mitotic counts increased, indicating that hyperplasia had occurred. Apoptosis was demonstrated at light microscopical level to be the main mechanism for cell deletion as the glands returned to normal size and weight. The results indicate that hypertrophy and hyperplasia of serous acinar cells contribute to isoproterenol-induced sialadenosis. The experimental animal model demonstrates that these proliferative changes are completed by 48 h and thereafter are balanced by apoptosis as the glands recover their normal size and weight.

Dose response and safety of cizolirtine citrate (E-4018) in patients with pain following extraction of third molars.

The objectives of this study were to determine the dose response and safety of the oral analgesic cizolirtine citrate (E-4018) in patients with postoperative pain after third molar extraction. This was a placebo-controlled, double-blind, randomised, parallel-group study. Doses of E-4018 were 50 mg, 100 mg, or 150 mg. The primary outcome measure of efficacy was patient assessment of pain severity, determined from serial visual analogue scales (VAS) over a four-hour investigation period. Other efficacy measures included the number of patients taking escape analgesic and the time before it was taken, and an overall assessment of pain relief on a four-point categorical scale. There was no significant difference between any of the E-4018 treatment groups and placebo in terms of the AUC for VAS pain scores over time. The percentages of patients who took paracetamol within five hours of their dose were 100%, 95%, 78% and 82% for the placebo, 50 mg, 100 mg and 150 mg E-4018 groups, respectively. The time to first use of paracetamol was significantly different for the 100 mg and 150 mg E-4018 groups compared to placebo. There were 17 adverse events, of which five were possibly related to the study medication (one in the placebo group and four in the 150 mg E-4018 group). We conclude that there was a dose-related trend in the percentage of patients requiring paracetamol within five hours of their study medication, and in the percentage of patients that recorded the treatment as providing good or excellent treatment of pain. There was, however, no firm evidence of a dose-related analgesic effect over the dose range of Cizolirtine chosen for this study. E-4018 was well tolerated in all patients.

The future role for oral exfoliative cytology--bleak or bright?

The role of exfoliative cytology in the screening for oral cancer has never achieved the same success as it has for diagnosing cancer of the uterine cervix. Yet the recent application of quantitative and immunocytochemical techniques has, to some extent, refined its potential role. However, the absence of a marker, present in all malignant lesions but never seen in benign lesions, limits its clinical utility and argues for the identification of a combination of markers, whose sensitivity and specificity require evaluation. It may well be that oral exfoliative cytology will enjoy its greatest success, not so much in screening, but rather as providing samples of DNA from biopsy proven oral cancers. Greater understanding of the type of mutation present may, in the future, predict not only tumour behaviour, but also its response to both traditional and novel forms of therapy.

p53 over-expression in laryngeal carcinoma is not predictive of response to radiotherapy.

It has been suggested that alteration involving the p53 gene may influence tumour response to radiotherapy. If this were so, then p53 overexpression (which is usually associated with p53 mutation and readily detectable in routine diagnostic pathology) may help determine the most appropriate form of cancer therapy. p53 expression was assessed in 90 formalin-fixed paraffin-embedded laryngeal carcinomas that were subsequently treated with radiotherapy. The polyclonal antibody DO1 (1 in 50 dilution) was used, together with an avidin-biotin immunoperoxidase technique, but in the absence of any additional antigen retrieval techniques. p53 expression was assessed and correlated with various clinicopathological parameters. Using Chi square analysis, no significant difference between p53 positive and p53 negative lesions was found for response to radiotherapy, as measured by survival and recurrence rates. Furthermore, no correlation with p53 expression was found for tumour size, nodal metastasis, sex, age, alcohol intake, tobacco habit and histological grade. This absence of correlation may in part be explained by discrepancies between immunohistochemical detection of p53 and p53 mutation, although the lack of predictive response to radiotherapy mimics that recently found for irradiated head and neck cancer cell lines.

An overview of the cell cycle arrest protein, p21(WAF1).

p21, also known as WAF1, Cip1, Sdi1, Mda 6 and Cap20 is a cell cycle protein that regulates and can arrest the cell cycle in G1 or S phase (either dependent or independent of p53). Its role may be pivotal in many cell processes including differentiation and apoptosis. This brief overview provides a summary of its presently known functions and indicates areas for further research, particularly in relation to oral malignant disease. Greater understanding of its role may lead to therapeutic advances in the management of malignant disease.

Possible mechanisms by which alcohol may influence the development of oral cancer--a review.

Although pure ethanol has never been shown to be carcinogenic in laboratory experiments, alcoholic beverages are now recognised as being important aetiological factors in the development of oral cancer. Despite this, the exact mechanism by which alcohol may exert an influence upon the oral mucosa has received less attention. An overview of the association of alcohol and oral cancer, both in combination with tobacco and without, is provided and consideration given to some of the pathways by which alcohol exerts its effect upon the oral mucosa.

The association between epithelial proliferation and disease progression in the oral mucosa.

The purpose of this study was to examine the possible association between epithelial proliferation and disease progression in the oral mucosa. Archival specimens of normal oral mucosa (n = 12), dysplasia (n = 17) and squamous cell carcinoma (n = 18) were sectioned and proliferating cells visualised by staining with Ki-67 antibody. The proliferative index of the epithelium (PI) was determined by total cell counts and point counting. Similar results were obtained using either method. Comparison of the three groups of tissues by one-way analysis of variance showed a significant increase in PI with increasing lesion severity (p < 0.001). The PI of both dysplasia and carcinoma groups was significantly higher than that of normal oral mucosa (p < 0.001). However, the difference between dysplasia and carcinoma groups was not significant. PI was not associated with tobacco or alcohol consumption. We therefore conclude that Ki-67 expression is an early marker of disease progression in the oral mucosa but, on its own, is not a good indicator of neoplastic transformation.

Fluid phase endocytosis within buccal mucosal cells of alcohol misusers.

The structure of the oral mucosa is now well characterised, although studies on oral epithelial cell function have received less attention. The aims of this study were to see whether endocytosis could be demonstrated in cells from oral smears and if so, to assess the effect of chronic high alcohol intake on such uptake. Buccal mucosal smears were collected from 135 patients (91 non- or social drinkers, and 44 patients with harmful alcohol use). Name, age, sex, and alcohol history (for alcohol problem patients) were recorded. Cell suspensions were incubated in a solution of bovine serum albumin (BSA)-coated fluorescently labelled latex microspheres (0.02 micron diameter) in Ham's F-10 culture medium for 1 h at 37 degrees C as a marker of fluid phase endocytosis. Uptake of microspheres was confirmed by confocal microscopy, and mean endocytosed fluorescence levels determined by flow cytometry. A repeat smear from 11 of the alcohol patients was taken 9-14 days later. Endocytosis was significantly reduced in both male (P < 0.01) and female (P < 0.01) alcohol problem patients compared to controls. Units of alcohol consumed and cigarettes smoked per day did not show a dose-response correlation with endocytosis in the alcohol problem patients. Apparent abstinence from alcohol had no further effect on endocytic uptake at days 9-14. This study shows that normal oral squamous cells removed as buccal smears readily endocytose fluorescent microspheres and that this capacity can be affected by alcohol. Chronic high alcohol intake would appear to down regulate endocytosis in buccal cells even up to 14 days of abstinence. This may have implications for the pathogenesis of oral mucosal disorders in long-term users.

A technique for the study of endocytosis in human oral epithelial cells.

Fluorescently labelled latex microspheres (0.01, 0.1 and 1.0 micron dia.) were used to establish whether oral epithelial cells could exhibit an endocytic function. Oral mucosa biopsies were incubated in organ culture at 37 degrees C for 20 h with one of the three sizes of fluorescent microspheres in the medium. Tissue pieces were then disaggregated and cell suspensions analysed for cell content and viability. Evidence of endocytosis was sought by using fluorescence-activated cell scanning (FACS) and confocal microscopy to study the epithelial cell suspensions for internalization of the microspheres. Confirmation that the microspheres had been internalized and were not merely attached to the cell exterior was shown by using trypan blue quenching to extinguish extracellular fluorescence, allowing analysis of only intracellular fluorescent microspheres. Both FACS and confocal microscopy confirmed uptake of 0.01 and 0.1 micron dia. microspheres but not 1.0 micron. Endocytosis was quantitated using FACS and a dose-dependent relation between the concentration of spheres in the incubation medium and uptake was found. Internalization of microspheres of < 1.0 micron dia. and the dose-dependent uptake support a fluid-phase constitutive endocytic process.

A histochemical study of carbonic anhydrase in the plasma membranes of human oral epithelial cells.

Carbonic anhydrase (EC 4.2.1.1) was detected histochemically from the following regions in patients of various ages (14-84 yr): buccal mucosa, buccal flap, hard palate and tongue. The enzyme was principally located in the cell membranes but was also present in nuclei. There was a gradation in activity from basal (strong) to superficial cells (weak/negative). The carbonic anhydrase inhibitors ethoxyzolamide and acetazolamide abolished activity at 0.001 mM, but were ineffective, even at 1.2 mM, against a reaction associated with the granules of the stratum granulosum. No activity was detected in the absence of bicarbonate from the substrate.

An immunocytochemical study of the carbonic anhydrase I isoenzyme in human oral Merkel cells.

Merkel cells in human buccal mucosa and hard palate possess the carbonic anhydrase I isoenzyme (CAI). CAI colocalized immunocytochemically with a range of Merkel cell cytokeratins, namely CK 7, 8, 18, 19 and 20. No other cells in the oral epithelium were immunoreactive for the CAI antibody. The presence of the enzyme may be related to the function of sensory receptors that produce a sustained response to a maintained mechanical stimulus.