The evaluation of Ki67, p53, MCM3 and PCNA immunoexpressions at the level of the dental follicle of impacted teeth, dentigerous cysts and keratocystic odontogenic tumors

The aim of this study is to analyze the immunoexpression of Ki67, p53, MCM3 and PCNA markers in epithelial remnants of dental follicles of impacted teeth and to identify a possible correlation between the immunoexpression of these markers in dentigerous cysts and keratocystic odontogenic tumors in order to evaluate their evolutionary behavior.

MATERIALS AND METHODS

A total of 102 cases were included in the study and divided into three subgroups: the first subgroup consisted of 62 cases with dental follicles of impacted teeth, the second included 20 cases of dentigerous cysts and the third subgroup comprised a number of 20 cases with keratocystic odontogenic tumors. Immunomarking with the four antibodies was performed.

RESULTS

A positive marking was obtained in over 60% of the dental follicles for all markers. Statistically significant differences were also obtained in dentigerous cysts and keratocystic odontogenic tumors for Ki67, p53 and MCM3. Assessment of the four antibodies in the two layers of keratocystic odontogenic tumors shows a positive correlation between Ki67 and MCM3 both for the basal and parabasal layer, with slightly increased values in the latter.

CONCLUSIONS

In order to determine the proliferative capacity of epithelial remnants in the dental follicles, Ki67 and PCNA, Ki67 and MCM3 are the most useful markers in practice; they have similar behavior and are more likely to help in distinguishing between dentigerous cysts and keratocystic odontogenic tumors.

The study of barium concentration in deciduous teeth, impacted teeth, and facial bones of Polish residents

The study determines the concentration of Ba in mineralized tissues of deciduous teeth, permanent impacted teeth, and facial bones. The study covers the population of children and adults (aged 6-78) living in an industrial area of Poland. Teeth were analyzed in whole, with no division into dentine and enamel. Facial bones and teeth were subjected to the following preparation: washing, drying, grinding in a porcelain mortar, sample weighing (about 0.2 g), and microwave mineralization with spectrally pure nitric acid. The aim of the study was to determinate the concentration of Ba in deciduous teeth, impacted permanent teeth, and facial bones. The concentration of barium in samples was determined over the ICP OES method. The Ba concentration in the tested bone tissues amounted to 2.2-15.5 μg/g (6.6 μg/g ± 3.9). The highest concentration of Ba was present in deciduous teeth (10.5 μg/g), followed by facial bones (5.2 μg/g), and impacted teeth (4.3 μg/g) (ANOVA Kruskal-Wallis rank test, p = 0.0002). In bone tissue and impacted teeth, Ba concentration increased with age. In deciduous teeth, the level of Ba decreased with children's age.

Early soft tissue pathosis associated with impacted third molars without pericoronal radiolucency

OBJECTIVES

This study was performed to histologically evaluate soft tissue pathosis in pericoronal tissues of impacted third molars that did not exhibit pathologic pericoronal radiolucency.

STUDY DESIGN

One hundred impacted third molars without evidence of abnormal pericoronal radiolucency (follicular space <2.0 mm) were removed for reasons other than participation in this study, and the pericoronal tissues were submitted for histopathologic examination. Specimens were fixed and processed routinely and were stained with hematoxylin and eosin before independent evaluation by each of 2 oral pathologists. A subset of both diseased and healthy tissues underwent additional evaluation for the presence of proliferating cell nuclear antigen (PCNA) for assessment of cellular activity.

RESULTS

Of the specimens submitted, 34% showed squamous metaplasia suggestive of cystic change equivalent to that found in dentigerous cysts. Soft tissue pathosis was significantly higher in patients over 21 years of age (P =.001). Five of 8 diseased specimens demonstrated PCNA uptake, whereas none of 10 healthy specimens were PCNA positive.

CONCLUSIONS

These findings suggest that radiographic appearance may not be a reliable indicator of the absence of disease within a dental follicle. We conclude that the incidence of soft tissue pathologic conditions is higher than generally assumed from radiographic examination alone.

High resolution electron microscopy of the initial mineral deposition on enamel surface

The human partially impacted third molar was used to investigate the initial stage of dental calculus on enamel surface. The thin layer of mineral deposition consisted of needle-like crystals. High resolution electron microscopy (HREM) revealed that these crystals directly contacted each other. Electron diffraction represented that needle-like crystals of calculus consisted of hydroxyapatite (OH-AP). These findings indicate that the high calcium (Ca) x inorganic phosphate (Pi) ion-product condition in an extremely narrow and closed environment produces the stable OH-AP precipitates and that the growth of calculus crystals is thought to advance through the additional mineralization.

Systemic lead absorption in human tooth roots

One-hundred and five impacted and erupted sound teeth were analysed for lead content by graphite furnace atomic absorption spectrophotometry. The results showed that lead accumulated before eruption, presumably soon after the onset of dentine formation. The accumulation in dentine was systemic, without any contribution from the oral environment. The amount of lead in dentine may denote the amount of absorption into the body and serve as a precise index to body burden as no absorption from the mouth can take place. In adults, impacted and erupted teeth can be used together in any research and the donor's age can be considered as the period of lead accumulation.

Fluoride concentrations in fissure and cervical enamel of unerupted human teeth

Fluoride concentration of fissure enamel from unerupted third molars was higher than that of the cervical-lingual but not cervical-buccal surfaces at a similar depth of the removed enamel. The highest fluoride concentration was found in the fissure enamel due probably to its earlier formation, higher permeability and embedding tissue before eruption.