Expression of Mcm2, geminin and Ki67 in normal oral mucosa, oral epithelial dysplasias and their corresponding squamous-cell carcinomas.

Proteins necessary for the normal regulation of the cell cycle include minichromosome maintenance protein 2 (Mcm2) and geminin. These are overexpressed in several premalignant and malignant tumours. The Mcm2/Ki67 ratio can be used to estimate the population of cells that are in early G(1) (licensed to proliferate), and the geminin/Ki67 ratio can determine the relative length of G(1). A high ratio indicates a short G(1) and a high rate of cell proliferation. Mcm2 and geminin have been scarcely explored in oral epithelial dysplasia (OED) and oral squamous-cell carcinoma (OSCC). The purpose of this study was to identify the expression pattern of Mcm2, Ki67 and geminin in normal oral mucosa (NOM), OED and their subsequent OSCC, to determine if expression could help predict the prognosis of OED. Paraffin sections of 41 OED cases that progressed to carcinoma, 40 OED without malignant progression, 38 OSCC and 15 NOM were immunostained with antibodies against Mcm2, geminin and Ki67. Labelling indices (LIs) increased progressively from NOM, OED and OSCC (Mcm2, P<0.001; geminin, P<0.001 and Ki67, P<0.001). In all the OED cases (n=81) the levels of expression of Mcm2 (LI, 73.6), geminin (LI, 24.4) and Ki67 (LI, 44.5) were elevated indicating a constant cell-cycle re-entry. When the OED groups were compared, Mcm2 protein expression was higher in the OED with malignant progression (P=0.04), likewise there was a significant increase in the Mcm2/Ki67 and geminin/Ki67 ratios (P=0.04 and 0.02 respectively). Mcm2 and geminin proteins seem to be novel biomarkers of growth and may be useful prognostic tools for OED.

DNA ploidy analysis by image cytometry helps to identify oral epithelial dysplasias with a high risk of malignant progression.

Abnormal DNA content (aneuploidy) has been associated with malignant and premalignant epithelial lesions. The presence of aneuploidy in tumours at an early stage and in dysplastic lesions suggests that analysis of DNA content may be a useful marker for determination of prognosis in these lesions. The aim of this study was to use DNA image cytometry to evaluate aneuploidy in oral dysplastic lesions and to determine whether aneuploidy is associated with malignant progression. Forty-two lesions of oral epithelial dysplasias (OED) that had progressed to oral squamous cell carcinoma (OSCC) and 44 lesions that did not progress were analysed for DNA ploidy using image cytometry of nuclear monolayers prepared from paraffin-embedded tissue. Forty-two OSCC that had arisen from the OED cases and five samples of normal oral mucosa samples (NOM) were also examined. Aneuploidy was found in 14/42 (33.3%) of the OED that progressed, but in only 5/44 (11.3%) of OED that did not progress (p=0.01). A total of 19 OED were aneuploid of which 74% showed malignant progression compared to only 42% of the diploid lesions. The sensitivity and specificity of DNA image cytometry to detect cases with high risk of malignant progression was 0.33 and 0.88, respectively. The PPV and NPV were 0.74 and 0.58. We conclude that aneuploid oral dysplastic lesions have a high risk of malignant progression and that DNA image cytometry might help to identify those lesions most at risk.

Expression of Mcm-2, Ki-67 and geminin in benign and malignant salivary gland tumours.

BACKGROUND: Recent studies have proposed that minichromosome maintenance (Mcm) proteins may be sensitive proliferation markers and may serve as novel biomarkers for prognostication and diagnosis of various pre-malignant and malignant lesions. The aims of this study were to determine the expression of Mcm-2, Ki-67 and geminin in salivary gland (SG) tumours, and to evaluate their usefulness for diagnosis or for prediction of tumour behaviour. METHODS: Tissue from 62 SG tumours was assembled in tissue microarray format. There were 13 adenoid cystic carcinomas (ACC), 10 carcinoma ex pleomorphic adenomas (CEPA), 10 mucoepidermoid carcinomas (MEC), 10 polymorphous low-grade adenocarcinomas (PLGA), 10 pleomorphic adenomas (PA) and nine acinic cell carcinomas (AcCC). Clinicopathological data were collected retrospectively and immunohistochemical analyses of Mcm-2, Ki-67 and geminin were performed on all lesions. Labelling index (LI) for each marker was determined by counting the percentage of positive cells in six random fields from three arrays per case. RESULTS: Mcm-2 expression was higher than Ki-67 and geminin in all tumours studied. Mcm-2 LI was higher in ACC (28.2 +/- 19.2%) than in CEPA, AcCC, MEC, PA and PLGA (5.3 +/- 4.1%, P = 0.001). Mcm-2 LI was higher in CEPA (20.4 +/- 5.0%) than in PA (6.9 +/- 5.0%, P = 0.001). LI did not correlate to tumour grade or outcome for any of the markers or tumour types. CONCLUSIONS: The findings suggest that Mcm-2 may be a sensitive proliferation marker in SG tumours and may be useful for differential diagnosis between PA and CEPA, and ACC and PLGA. Further studies are warranted to assess the value of Mcm-2 as a predictor of recurrence and survival.

The range and demographics of salivary gland tumours diagnosed in a UK population.

Salivary gland tumours are relatively rare and comprise a diverse range of neoplasms. The aim of this study was to determine the range and demographics of all histologically diagnosed salivary tumours in a European population. All entries for salivary gland tumours from 1974 to 2005 inclusive were retrieved and analysed for each diagnosis including number of specimens, male:female ratio and age range. These data were then analysed for the distribution of benign and malignant salivary tumours in major and minor salivary glands. 58,880 specimens were received; of these, 741 cases (1.3% of all specimens) were diagnosed as salivary gland tumours with a male to female ratio of 0.7:1. There were 481 (64.9%) benign and 260 (35.1%) malignant neoplasms, with the most common tumours being pleomorphic adenoma and mucoepidermoid carcinoma, respectively. Our study provides demographic data on a large series of salivary gland tumours in a European population. Accurate diagnosis is essential as salivary lesions have diverse clinical and prognostic outcomes. This study has confirmed that some tumours have a predilection for certain sites and that the risk of malignant disease is also greater at specific sites within the oral cavity.

A survey of the incidence of missing anterior teeth: potential value in bite mark analysis.

Bite mark analysis involves comparison of individual dental characteristics between a dentition and the bite injury. A bite mark injury may result from sexual assault, or physical assault, and defensive injuries, and as such can be used to link a suspect to a victim or vice versa. Missing teeth are one of the characteristics that could implicate or exclude a suspected biter. However frequency data for use by forensic odontologists can only be collated from epidemiological studies. Therefore an audit was undertaken of missing anterior teeth in adult patients (n = 1010) attending for treatment, gathering data that could be more relevant to odontology. One in five of the sample presented with missing teeth that were either replaced with a denture (11%), not replaced (6%) or missing with the gap closed (2%).

Range and demographics of odontogenic cysts diagnosed in a UK population over a 30-year period.

BACKGROUND: The aim of this study was to determine the range of all histologically diagnosed odontogenic cysts along with age range, sex distribution and site of presentation over a 30-year period. METHODS: All entries for odontogenic cysts occurring during 1975-2004 inclusive were retrieved and analysed for demographic data. RESULTS: A total of 55,446 specimens were received, of these 7121 (12.8%) specimens were diagnosed as odontogenic cysts. Radicular cyst was the most common diagnosis (52.3%), followed by dentigerous cyst (18.1) and odontogenic keratocysts (11.6%). CONCLUSIONS: Our study provides demographic data on a large series of odontogenic cysts in a European population. This is one of the largest series reported to date. Cysts such as the paradental cyst have a predilection for certain ages, sexes and sites. Odontogenic keratocysts and glandular odontogenic cysts have a marked propensity to recur as well as behave aggressively. It is essential that such lesions are detected as early as possible to minimize any necessary surgery.

External cervical resorption of a primary canine.

The authors describe the case of a 3-year-old boy who presented with a mobile right maxillary primary canine. Clinical examination revealed this tooth to have an abnormally large crown, which appeared to have sustained a crown-root fracture. Periodontal probing depths of 5 mm were detected around the tooth. Radiographically, there was a marked constriction at the cementoenamel junction with associated alveolar rarefaction. Both upper primary canines were subsequently removed under general anaesthetic and the right canine was subject to histopathological investigation. A diagnosis of external cervical resorption was made. A review of the literature confirmed this to be a very unusual case presentation.

In vitro and in vivo evaluation of e-PTFE and alkali-cellulose membranes for guided bone regeneration.

Guided bone regeneration (GBR) is employed to encourage the formation of new bone in osseous defects by restricting the infiltration of soft tissues. While a variety of membranes have been evaluated for this surgical procedure, the non-resorbable material of choice is currently expanded polytetrafluoroethylene (e-PTFE). A new alkali-cellulose membrane produced by a biotechnological process has been developed as an alternative to e-PTFE for GBR. In this study, the biocompatibility of this novel alkali-cellulose membrane and e-PTFE was compared using tissue culture and an in vivo GBR model. In vitro both materials supported the attachment, migration and differentiation of osteoblast-like cells in culture for up to 3 weeks. The in vivo model was based upon full-thickness transcortical bone defects in the mandibular rami of Sprague-Dawley rats. The right rami were used as controls, contralateral defects being covered bucally and lingually with either e-PTFE or alkali-cellulose membranes. Pathological and histomorphometric analysis was undertaken at 4 and 10 weeks post-implantation. Bone regeneration associated with alkali-cellulose membranes was predominantly endochondral in type in contrast to e-PTFE which induced direct bone formation (intramembranous ossification). The amount of new bone formed in defects was similar for both types of membrane, but alkali-cellulose membranes induced significantly greater inflammatory response; characterized by lymphocytes, macrophages and multinucleated giant cells. Degradation and possible exposure of individual cellulose fibres may account for the poor performance of alkali-cellulose membranes in vivo. This animal and in vitro study indicates that when choosing a non-resorbable membrane for GBR, e-PTFE membranes are likely to perform better than those produced from alkali-cellulose.

Glass-ionomer cement: evaluation as an orbital implant.

BACKGROUND: To assess the potential of a porous glass-ionomer cement (GIC) as an alternative material for spherical orbital implants, the handling, side effects and rates of fibrovascular ingrowth of this material were compared with those of a synthetic hydroxyapatite (HA) implant. METHOD: Twenty-one GIC and 8 HA uncovered 14-mm spheres were implanted into the orbits of New Zealand albino rabbits. Postoperative reactions, animal's behaviour, weight increase and socket conditions were monitored. Light and electron microscopy of the exenterated orbits were performed 2, 3 and 6 months after primary insertion. RESULTS: Implanting of GIC was easier than HA. Postoperatively all animals did well. Three HA and 1 GIC implant caused conjunctival dehiscences, but no implant extrusion was observed. Histologically, both materials caused mild inflammation in the surrounding connective tissue capsule, decreasing with time. GIC implants proved to be not truly porous, with only peripheral pores partly occupied by relatively acellular collagenous connective tissue. Free glass particles were observed in both the connective tissue and giant cells, occupying the partly filled pore spaces. HA implants showed extensive ingrowth of vital host tissue from the beginning. CONCLUSIONS: Considering the clinical findings and the mild inflammation in the connective tissue capsule surrounding both materials, they would appear to be equally well tolerated at the implant site. The significantly different microstructure and the histological results make GIC, despite better handling, less suitable as an orbital implant.

Bone healing following the use of hydroxyapatite or ionomeric bone substitutes alone or combined with a guided bone regeneration technique: an animal study.

The healing of standardized bone defects grafted with either particulate ionomeric or hydroxyapatite bone substitutes was compared in the mandibular ramus of 30 Sprague-Dawley rats. The possible additional response achieved when combining these materials with a guided bone regeneration (GBR) technique was also evaluated. Three groups of 10 animals received either no implant material or ionomeric or hydroxyapatite bone substitute in defects in the right ramus. The left mandibular defects received the same treatment, except that the operation site was covered by a membrane (GBR technique). Half of the animals were sacrificed at 4 and 10 weeks following surgery, and the inflammatory response at the implant site and the amount of new bone formed in the defects were determined histomorphometrically. Defects implanted with ionomeric bone substitute exhibited more bone formation (4 weeks = 3.19 +/- 0.35 mm2, 10 weeks = 5.35 +/- 0.26 mm2) than both defects that received no treatment (4 weeks = 0.88 +/- 0.35 mm2, 10 weeks = 2.1 +/- 0.49 mm2), membrane alone (4 weeks = 1.21 +/- 0.05 mm2) or hydroxyapatite bone substitute (4 weeks = 1.41 +/- 0.46 mm2, 10 weeks = 3.34 +/- 0.41 mm2) at 4 weeks (P < or = .01) and at 10 weeks (P < or = .05). The use of a GBR technique did not increase the amount of bone formed, compared to the use of bone substitutes alone. Hydroxyapatite and ionomeric bone substitutes used alone were more effective in inducing repair of the defects than was GBR membrane alone. The use of hydroxyapatite was associated with a greater inflammatory reaction (P < or = .01) than was ionomer in this model.

Burkitt's lymphoma presenting with jaw lesions in a young white girl.

We report a case of Burkitt's lymphoma that presented with jaw lesions in a 5-year-old white girl, an extremely rare occurrence. She was treated according to the protocol of the UK Children's Cancer Study Group B-cell non-Hodgkin's lymphoma trial and was still in remission after 2 years.

Allergy to octyl gallate causing stomatitis.

Octyl gallate is an antioxidant (European Community number 311). It is used as a preservation agent in a wide variety of foods and other non-dietary substances. We report a case of a 49-year-old female with a 10-year history of 'burning mouth' and clinical erythema of the tongue, who, after investigation, proved to be allergic to octyl gallate. Management with an exclusion diet proved effective in both controlling the burning sensation and resolving the erythema of the tongue.

Bone cell interactions with a granular glass-ionomer bone substitute material: in vivo and in vitro culture models.

The interface between bone and a synthetic bone substitute constructed from glass-ionomer cement (ionomeric microimplant) was studied in diffusion chambers implanted in a primate baboon model (Papio ursinus) and in in vitro primary bone organ cultures derived from neonate rat calvaria. In both models osteoblast-like cells colonized the surface of the implant producing a collagenous extracellular matrix. An electron-dense bonding zone similar to that reported for hydroxyapatite and titanium was seen in both models but was a more constant feature of the tissue/implant interface in calvarial culture.

In vitro interaction between primary bone organ cultures, glass-ionomer cements and hydroxyapatite/tricalcium phosphate ceramics.

Primary organ cultures derived from neonate rat calvaria were maintained for 2 wk and used to study in vitro response of osteoblast and periosteal cells to the component and composite forms of three different glass-ionomer (polyalkenoic) cements, comparing them to densely sintered hydroxyapatite and tricalcium phosphate ceramics. Qualitative analysis by scanning and transmission electron microscopy revealed that osteoblasts colonized all the solid test materials, although there was a less favourable response to materials with a rough surface topography and to unset and fluoride-containing glasses. On solid materials migrated cells maintained their tessellated morphology and exhibited numerous micro-appendages anchoring them to the surface of the test materials. A collagen-containing extracellular matrix was elaborated on to the ceramics and set glass-ionomer cements, except for one (AquaCem). Mineralization of the extracellular matrix was seen adjacent to hydroxyapatite and tricalcium phosphate ceramics, that adjacent to the latter morphologically resembling bone.

Initial in-vivo evaluation of glass-ionomer cements for use as alveolar bone substitutes.

The response of rat femora to implantation of four glass-ionomer (polyalkenoic) cements (GIC) compared to that seen following implantation of densely sintered hydroxyapatite (Ha) ceramic was evaluated for periods up to 12 weeks. Light and transmission electron microscopic analysis of the GIC/bone interface revealed direct bonding of the GIC G338 and Ketac Cem (both based on fluoro-alumino-silicate) glasses to bone, with a mineralized collagen-containing extra-cellular matrix deposited on the surface of the GIC. AquaCem and the fluoride-free GIC based on MP4 glass showed incomplete osseointegration.

A radicular dens invaginatus.

A case of the radicular type of dens invaginatus involving a mandibular third molar is reported. The clinical presentation and histopathology are described and the development and significance of such lesions discussed.

Tissue response to subperiosteal implantation of dense hydroxyapatite: case report.

Hydroxyapatite is becoming a popular implant material, yet reports on the tissue response it evokes in humans have been few in number and are based on relatively short periods of implantation. In the present case, implant material became available when it proved necessary to modify an alveolar ridge augmentation procedure carried out 18 month previously. Histology showed that whilst some parts of the implanted material were embedded only in fibrous tissue, others had become fully integrated within partly remodelled bony trabeculae. These findings confirm the status of hydroxyapatite as a biocompatible implant material and provide further evidence of its bone-bonding and osteoconductive capacities.

Quantitation of lactoferrin in odontogenic cyst fluids.

A competitive enzyme linked immunosorbent assay (ELISA) method was used to measure the concentration of lactoferrin in fluids from 36 odontogenic keratocysts, 15 dentigerous cysts, and 30 radicular/residual cysts. Keratocyst fluids contained significantly higher concentrations of lactoferrin than fluids from the other two types of cyst (p less than 0.001); but the range of values obtained within each group was large. Although lactoferrin represents a larger proportion of the total protein in keratocyst fluids than in dentigerous or radicular cyst fluids, lactoferrin concentration is not an absolute diagnostic marker for keratocysts. Lactoferrin concentration correlated strongly with the numbers of neutrophils present in keratocyst fluids (p less than 0.001), less so for dentigerous cyst fluids (p less than 0.05, and not at all in the case of radicular cyst fluids. It is suggested that neutrophils are the source of lactoferrin in the three categories of cyst studied but that the relatively impermeable nature of the keratocyst lining probably accounts for the particularly high concentrations of lactoferrin found in their fluids. Given that most keratocysts were asymptomatic, acute inflammation itself does not explain the reason for the high numbers of neutrophils in many of the fluids.

External resorption of a maxillary lateral incisor by a labially placed canine: pathology and management.

A case is presented showing external resorption of a maxillary lateral incisor associated with a labially placed canine. The histological appearance and differential diagnosis is discussed, and the treatment described.

Evidence for the presence of lactoferrin in odontogenic keratocyst fluids.

Investigations into the possibility that X (an antigen consistently present in aspirated odontogenic keratocysts, but not in most fluids from other cyst types), represented a keratinocyte component failed to identify the antigen as a keratin, involucrin, or one of the blood group substances. Antigen X was detected in human mixed and parotid saliva and in colostrum, as well as in a commercially obtained preparation of colostral IgA. The antigen was similar biochemically to both secretory component and lactoferrin but proved to be identical antigenically with lactoferrin. The origin of lactoferrin in keratocyst fluids remains uncertain, though the lining epithelium seems a more likely source than does the very variable, and often negligible, inflammatory infiltrate found in these lesions.