Božidar Pavelić

Involvement of PTCH gene in various noninflammatory cysts

Constitutional hemizygous inactivation of PTCH, the Shh signaling pathway gene that moderates the signal, manifests itself as nevoid basal cell carcinoma syndrome or Gorlin syndrome, a condition variably characterized by a number of developmental disorders and malformations, and by predisposition to some malignancies, basal cell carcinoma in particular. Loss of heterozygosity for the PTCH region was found several years ago in the epithelial lining of odontogenic keratocysts, the cyst type with highly increased incidence in nevoid basal cell carcinoma syndrome. This finding confirmed the expectations that the gene responsible for the syndrome would have a decisive role in the genesis of these cysts even when they are not syndrome related. Suggestive temporal distribution of Shh signaling, recently observed during tooth development, lead us to investigate PTCH association with dentigerous cysts, the other major noninflammatory cyst of odontogenic origin. We report here that PTCH appears to be inactivated in dentigerous cysts, suggesting that it is responsible for their genesis as well. More generally, if our similar observations of incomplete heterozygosity in this region for dermoid cysts can be interpreted as loss of heterozygosity, PTCH alterations may prove to be a necessary, and perhaps the initiating event, in formation and growth of various noninflammatory cysts. This would be consistent with our view that local PTCH inactivation can, under favorable circumstances, lead to persistent though not by itself truly aggressive cell proliferation.

Alterations of FHIT and P53 genes in keratocystic odontogenic tumor, dentigerous and radicular cyst

BACKGROUND The purpose of this study was to determine fragile histidine triad (FHIT) and p53 protein expression, and to analyze FHIT and p53 gene status in keratocystic odontogenic tumor (KOT), dentigerous cysts (DC) and radicular cysts (RC). METHODS The methods used were immunohistochemistry and molecular genetic methods including loss of heterozygosity (LOH) and gene sequencing. RESULTS FHIT protein expression was different among groups. Aberrant expression was the highest in KOT, then in RC and DC. p53 protein expression was different among groups. LOH in paraffin-embedded specimens was detected in 22.6% and 12.9% for FHIT and p53 respectively. Mutation of p53 gene at codon 237 was observed in only two specimens (one KOT and one DC). Of the six frozen specimens, three exhibited FHIT gene LOH (two RC and one KOT). KOT showed loss of exons 6-7 at FHIT locus and mutation at codon 237 at p53 locus, but this could be a chance result. CONCLUSION Aberrations of FHIT and p53 genes/proteins could be considered markers responsible for the development of odontogenic lesions.

In vitro pulp chamber temperature rises associated with the argon laser polymerization of composite resin.

This in vitro study was performed upon 50 extracted human molars that provided the occlusal surfaces for standard class I preparations. The cavity floor of the 20 specimens was covered with zinc phosphate cement and the teeth were sectioned transversally at or below the cemento‐enamel junction. In some specimens pulp tissue was removed from the pulp chamber. The cavities of all specimens were filled with composite resin, and the resin was cured with an argon laser.

The Emergence and Ozone Treatment Studies of Living Cells

Most processes in biomedicine can hardly be addressed within some physicists’ reductionist views. More appropriate is the emergence approach, the process of complex pattern formations from simpler rules, that was introduced by biologists, and that has a natural place within bio-complexity. There is nothing that commands the system to form an emergent pattern, but instead the interactions of each part, to its immediate surroundings, causes a complex process which leads to some form of order. One such emergent process in re-balancing of tissue cells is the high-frequency bio oxidative treatment. Ozone therapy is a well established alternative and complementary treatment in most mainland EU countries and The European Cooperation of Medical Ozone Societies publishes guidelines on medical indications and contraindications of ozone and hosts expert training seminars. Here we describe the accumulated know-how on the use of feeble active flux of ozone in the cell healing and briefly discuss several tested ozone treatments in dentistry and medicine (herpes, muscle recovery, injury recovery etc.).

Associated With the Argon Laser Polymerization of Composite resin

STUDY DESIGN/MATERIALS AND METHODS This in vitro study was performed upon 50 extracted human molars that provided the occlusal surfaces for standard class I preparations. The cavity floor of the 20 specimens was covered with zinc phosphate cement and the teeth were sectioned transversally at or below the cementoenamel junction. In some specimens pulp tissue was removed from the pulp chamber. The cavities of all specimens were filled with composite resin, and the resin was cured with an argon laser. RESULTS A statistically significant difference in the rise in temperature was obtained only in the temperature of dentin roof of the pulp chamber between the specimens with (2.2 degrees C) and without (3.1 degrees C) cement base (P < .05). There was no significant difference in the temperature of the pulp tissue between specimens with (2.7 degrees C) and without (2.2 degrees C) base cement. The peak temperature of the composite surface was 13.8 degrees C. CONCLUSION These data indicate that argon laser curing may be a method of choice for polymerization of the composite resin.