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Glycosaminoglycans (GAG) were extracted from the connective tissue of 15 dental cysts, 2 dentigerous cysts and 7 keratocysts, and separated electrophoretically and chromatographically. Hyaluronic acid (dental, 2.38; dentigerous, 3.98; keratocyst, 3.19 micrograms uronic acid/mg lyophilized tissue) was the major GAG detected, with lesser amounts of heparin (dental, 1.70; dentigerous, 1.95; keratocyst, 1.80 micrograms uronic acid/mg lyophilized tissue) and chrondroitin-4-sulphate (dental, 1.33; dentigerous, 2.85; keratocyst, 1.37 micrograms uronic acid/mg lyophilized tissue). It is suggested that enzymic release of these GAGs allows their diffusion into the luminal fluid where they may contribute to expansile cyst growth.

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.

Fluids from non-keratinizing cysts of the jaws contain the main proteins found in plasma. The low relative concentration of macromolecular non-immunoglobulin proteins shows that there is no free passage of plasma proteins into the cyst fluid. Sufficient evidence was found to conclude that the immunoglobulins in cyst fluid are partly produced locally and partly derived from plasma. Cyst fluid immunoglobulins have antibody activity to rabbit erythrocytes. Accumulation of cyst fluid is primarily due to inadequate lymphatic drainage of the cyst cavity. Differential diagnosis between various types of non-keratinizing cysts cannot be based on the plasma protein patterns of their fluids.

Prostaglandin E2 and F2 alpha concentrations in aspirated cyst fluid of 14 human dental cysts were measured by radioimmunoassay. The mean concentrations were found to be 22.0 ng PGE2/g cyst fluid and 4.0 ng PGF2 alpha/g cyst fluid. As compared to plasma conditions a remarkable shift of the ratio of the two prostaglandins to PGE2 could be demonstrated. Due to the high concentrations of PGE2 found in the cyst material it is suggested that this prostaglandin may be one of the bone resorbing factors to be responsible for the destruction of bone in periodontal diseases.

The fluids of 44 dental cysts, 19 dentigerous cysts, 36 odontogenic keratocysts, and 12 ameloblastomas have been investigated. The incidence of epithelial cells, inflammatory cells, cholesterol crystals and bacteria was recorded in smears. There was a high incidence of epithelial cells in odontogenic keratocysts and not in other lesions. Cholesterol crystals had a similar incidence in all lesions. The proportion of the soluble proteins and total protein content was determined from cellulose acetate electrophoresis. Dental cysts contained an average of 51.19% albumin, 17.52% beta globulin, 22.04 % gamma globulin, and 6.30 g/100 ml protein. Dentigerous cysts contained an average of 61.35% albumin, 13.98% beta globulin, 12.70% gamma globulin and 5.40 g/100 ml protein. Odontogenic keratocysts contained an average of 78.03% albumin, 7.51% beta globulin, 7.91% gamma globulin, and 2.09 g/100 ml protein. Ameloblastomas contained an average of 67.38% albumin, 12.83% beta globulin, 12.60% gamma globulin and 4.86 g/100 ml protein. The immunoglobulin content was determined by single radial immunodiffusion. Dental cysts contained an average of 488.9 mg/100 ml IgA, 2535.4 mg/100 ml IgG, and 135.6 mg/100 ml IgM. Dentigerous cysts contained an average of 308.4 mg/100 ml IgA, 1618.2 mg/100 ml IgG, and 155.6 mg/100 ml IgM. Odontogenic keratocysts contained an average of 135.6 mg/100 ml IgA, 491.9 mg/100 ml IgG, and 54.1 mg/100 ml IgM. The significance of these findings in the pathogenesis and diagnosis of these lesions is discussed.

The fibrinolytic activity in the tissues of cystic lesions of jaw bones was investigated by the semiquantitative method of Astrup. The specimens examined were ameloblastoma (9 cases), follicular cyst (8 cases) and radicular cyst (14 cases). High fibrinolytic activity was observed in ameloblastoma, while in radicular cyst the activity was variable. It is suggested that in radicular cyst inflammatory episodes play an important role in activating local fibrinolysis, while in ameloblastoma the tissue itself has a great capacity to induce locally activated plasmin.

Glycosaminoglycans and proteoglycans were analysed in keratinizing and nonkeratinizing odontogenic cyst fluids. Hyaluronic acid showed the highest incidence and abundance amongst the glycosaminoglycans detected. Appreciable amounts of chondroitin-4-sulphate were also observed, particularly in the dental cysts, with lesser amounts of the other glycosaminoglycans. Heparan sulphate showed a higher incidence and abundance in the keratocyst than the other cysts, whilst chondroitin-6-sulphate could not be detected in any of the cysts. A considerable proportion of the glycosaminoglycans of the fluids appeared to be complexed with protein and was released only after proteolytic digestion. The origin of these macromolecules is uncertain although it is likely that they are derived from both the connective tissue and the epithelium of the cyst wall.

The DNA content of the epithelial basal cells of oral lesions was determined by Feulgen microspectrophotometry. The DNA histograms of the radicular cysts showed a definite peak in the diploid range and a slight deviation to the right. The keratocysts also showed a well-defined modal peak in the diploid range; however, another cell population defined a peak in the tetraploid range. In leukoplakias of the oral cavity, two different profiles of DNA distribution were found. Where both the clinical and microscopic traits defined a nondysplastic lesion, the histogram showed a diploid peak and a percentage of cells in diploid-tetraploid range. For the more active lesion, a shift of the mode towards higher values was evident. The microspectrophotometric studies of oral epidermoid carcinomas showed a broad distribution towards the right and ill-defined modal values.

The keratin proteins were extracted from the epithelial lining of three odontogenic keratocyst specimens. Two of the specimens were from a patient with nevoid basal cell carcinoma syndrome; the third was a solitary lesion. Seven keratin proteins with molecular weights of 46, 48, 50, 52, 54, 58, and 59 kilodaltons were identified by SDS-polyacrylamide gel electrophoresis and immunoblotting with antikeratin antiserum. The reproducibility of the pattern of molecular markers implies a series of genetic events coincident with the characteristic pattern of epithelial differentiation.

The odontogenic cysts contain the hyaline deposits in 69.2%. The hyaline deposits appear as a zone that was continuous with basament membrane or as an irregular deposit within the connective tissue.

Hyaline bodies of odontogenic cyst were examined by histological, histochemical and electron microscopic observations. They were seen only in odontogenic cysts and their prevalence was 6.9% in 576 cases of the cysts. They occurred most frequently within the epithelial lining, but a few bodies were observed in the connective tissue walls. Histochemical reactions of hyaline bodies were similar to those of dental cuticles, but differed from keratin. Ultrastructurally, hyaline bodies were typed into two forms: lamellated and homogeneous. The lamellated bodies were composed of alternate electron-dense and electron-lucent layers. The homogeneous bodies were occasionally formed around granular material, mineralized masses and cholesterol clefts. Hyaline bodies adjoined epithelial cells via a basal lamina-like structure and half-desmosomes. Epithelial cells containing well-developed, rough surfaced, endoplasmic reticulum were seen adjacent to hyaline bodies. Ferritin-like granules were found in the cytoplasm of epithelial cells near hyaline bodies. By electron probe X-ray microanalysis, inorganic elements within the ferritin-like granules were the same in constitution as those in the outermost electron-dense layer of the lamellated bodies. By scanning electron microscopy, hyaline bodies displayed ellipsoidal and stick-like shapes. The present study suggested that hyaline bodies are particular products formed by odontogenic epithelium.

Forty-seven cyst fluids and autologous sera were examined for lipoproteins (LP) by cellulose acetate membrane (CAM) electrophoresis, immunoelectrophoresis and quantitative analyses for beta-lipoprotein and cholesterol. By CAM electrophoresis all cyst fluids showed alpha1-LP and betal-LP bands but no pre-beta-LP band. Four cyst fluids exhibited and additional, well-defined lipid-staining band located within the gamma-globulin zone (post-beta-band). The relative amount of alpha1-LP was higher in cyst fluid than in serum. Single radial immunodiffusion showed that the content of beta-LP was low. On an average, cyst fluid contained more cholesterol than did serum. Some cyst fluids were particularly rich in cholesterol. It is hypothesized that the cholesterol is derived partly from beta-LP originating from plasma.

Microprobe analysis of Araldite embedded sections of hyalin bodies revealed the presence of sulphur, chlorine, calcium and in some cases iron. The results have been compared with those obtained from control tissue sections of human heel skin, a thrombus occluded vessel and mineralized spherules in a dental follicle. Microradiographic studies showed that the density of hyalin bodies increased progressively towards the core. Isodensitracing confirms the laminar configuration of hyalin bodies as seen electron microscopically. The findings conform with the hypothesis that hyalin bodies originate as an epithelial secretion.

The possibility that the presence of lactoferrin in aspirates of odontogenic cyst fluid might be a useful preoperative diagnostic marker for odontogenic keratocyst was investigated. Using qualitative and quantitative immunodiffusion methods fluid from 29 of 29 dental (radicular) cysts, 12 of 14 dentigerous cysts and 27 of 31 keratocysts were found to contain lactoferrin. Although some of the highest concentrations of lactoferrin were detected in fluids from keratocysts, there was no significant difference between lactoferrin concentrations among the three groups. Neutrophil elastase was detected in 20 of 24 samples tested, 22 of which also contained lactoferrin. Immunocytochemical localisation of both lactoferrin and elastase was confined to neutrophils infiltrating cyst walls. These results suggest that lactoferrin in fluid from odontogenic cysts is derived from infiltrating neutrophils and that its presence in aspirated fluids is not a useful diagnostic marker for odontogenic keratocyst.

A botryoid odontogenic cyst (BOC) which recurred 4 times over a period of 9 years is presented. Immunocytochemical comparison of cytokeratin composition of the cyst epithelium with that of the overlying oral epithelium showed distinct differences. The cyst epithelium expressed keratins typical of both simple and nonkeratinizing squamous epithelia. The keratin profile of BOC is in line with previous findings on odontogenic epithelia, thus confirming its odontogenic origin.

The relationship of the keratocyst antigen (KCA), the soluble component present in most keratocyst fluids, and keratin, was studied with immunofluorescence microscopy comparing their distribution in developing mouse embryonic teeth and in human ameloblastomas. In these tissues both molecules showed a strong codistribution in epithelial cells. In the embryonic teeth both molecules were present in the stratum intermedium cells between the stellate reticulum cells and ameloblasts, but the secretory ends of the ameloblasts showed fluorescent staining only for keratin. The relationship was further investigated by comparing the physicochemical characteristics of KCA and keratin. Results on immunoblotting and two-dimensional gel electrophoresis showed that KCA existed in keratocyst fluid as a 60-68,000 dalton polypeptide with an isoelectric point of pI 6.8. Immunoblotting analysis of various isolated keratins revealed a typical polypeptide pattern of each keratin when anti-KCA antiserum was used for staining. These findings suggest that KCA and keratin are related molecules and that KCA may be a soluble component of keratin.

The patterns of cytokeratin expression in the epithelium of 5 dental follicles, 7 dentigerous cysts, 5 odontogenic keratocysts, 3 nasopalatine cysts and an epidermoid cyst have been studies using a panel of monoclonal antibodies. The epithelium of dental follicles and of developmental odontogenic cysts strongly expressed keratins 5 and 19 and showed weaker expression of keratins typical of stratified non-cornified and of simple epithelia. Staining with mAbs against the latter keratins varied with the degree of epithelial differentiation. Nasopalatine cysts strongly expressed simple epithelial keratins and the epidermoid cyst strongly expressed a marker of cornification. Odontogenic cysts thus appear to differ in their pattern of keratin expression from other oral developmental cysts and all derivatives of odontogenic epithelia appear to share similar basic patterns of cytokeratin expression.

X-ray microanalysis has revealed qualitative differences in the elemental composition between so-called hyaline bodies occurring in the connective tissue wall of an odontogenic cyst and hyaline bodies occurring within the epithelial lining of these cysts.