Biomedical subjects

Petros D Damoulis

Publications and source records attributed to Petros D Damoulis.

4 recordsLinked to original sources

PubMed2006

Expression of stem cell factor and its receptor, c-kit, in human oral mesenchymal cells.

Stem cell factor (SCF) is the pleiotropic ligand for the tyrosine kinase receptor, c-kit. Ligand and receptor are usually expressed in different cell types, and binding of SCF to c-kit promotes cell proliferation, differentiation, and recruitment of progenitor cells in various biologic systems. However, the localization of these two molecules in cells of the oral cavity has not been systematically examined. We investigated the expression of SCF and c-kit in human dental pulp (HDP) cells as well as in human gingival fibroblasts (HGF). Both alternatively spliced isoforms of SCF were detected (through reverse transcription-polymerase chain reaction) in RNA obtained from the two cell types. Western analysis established that both cell types express SCF and/or c-kit, whereas flow cytometry demonstrated distinct cell populations expressing only the ligand (SCF), only the receptor (c-kit), or co-expressing the two. HDP cultures showed higher soluble SCF (sSCF) production associated with faster cell growth, as compared with HGF cultures. In both cell types, however, sSCF levels appeared to increase as a result of in vitro aging and/or differentiation.

Animals↗

PubMed2006

Postoperative complications following gingival augmentation procedures.

BACKGROUND: Postoperative pain, swelling, and bleeding are the most common complications following soft tissue grafting procedures; however, detailed documentation is sparse in the literature. The aims of this prospective study were as follows: 1) to compare the frequency of complication occurrence after free soft tissue grafting (FSTG) or subepithelial connective tissue grafting (SCTG) procedures; 2) to evaluate the use of an acellular dermal matrix (ADM) as the donor tissue alternative to an FSTG or SCTG; and 3) to identify possible predictors for these complications. METHODS: Seventy-five FSTG and 256 SCTG procedures were performed in 228 patients by a single operator. In five free soft tissue and 84 bilaminar graft procedures, an ADM was used instead of autogenous tissue. Variables such as the duration and location of procedures, smoking history, gender, and age were recorded. Patients were asked to fill out a questionnaire 1 week after the surgeries regarding postoperative pain, swelling, and bleeding. Data were analyzed using the chi2 test and logistic regression analysis. Odds ratios were calculated for moderate and severe adverse outcomes grouped together. RESULTS: The duration of surgical procedures was highly correlated with pain or swelling post-surgically (P = 0.001). Current smokers were three times more likely to experience post-surgical swelling (P = 0.01). Patients who underwent FSTG procedures were three times more likely to develop post-surgical pain (P = 0.002) or bleeding (P = 0.03) compared to those who received SCTG procedures. When an ADM was applied instead of autogenous tissue, the probability of swelling or bleeding was significantly reduced (odds ratio [OR] = 0.46, P = 0.02 and OR = 0.3, P = 0.001, respectively). CONCLUSIONS: Long surgical procedures and smoking may increase the severity and frequency of certain post-surgical complications after gingival augmentation procedures. FSTG procedures incur a higher likelihood for postoperative pain or bleeding than SCTG procedures, whereas the application of an ADM may significantly reduce the probability of swelling and bleeding.

Adult↗

PubMed2004

Clinical significance of the structural integrity of the superior aspect of the mandibular canal.

BACKGROUND: Sparse data can be found regarding the structural integrity of the superior aspect of the mandibular canal. In many cases, the mandibular canal must be carefully evaluated prior to defining patient treatment. METHODS: In this case report, a 54-year-old patient presented with a periapical infection involving the mesial root of the mandibular right second molar (#31). Radiographic evaluation revealed that the periapical lesion extended from the apex of the tooth to the superior aspect of the mandibular canal. Upon surgical removal of the tooth, an apical communication between the extraction socket and mandibular nerve was located. A guided bone regeneration procedure was performed to protect the nerve from subsequent damage and to prepare the site for future implant placement. Implants were placed in the area approximately 5 months following the regenerative procedure. RESULTS: After implant placement, the patient experienced normal function and no mandibular symptomatology. Implants have been in function for the past 4 years. CONCLUSIONS: Many factors, both pathologic and developmental, can lead to a discontinuity of the superior aspect of the mandibular canal. Normally, a thin cortical plate of bone protects the nerve. When a lack of structural integrity of the canal roof is discovered, enucleation of a periapical infection or subsequent implant placement can lead to potential disruption of the nerve. Limited information is available regarding the integrity of this protective cover. This case report underscores the importance of proper clinical diagnosis before implant placement in the posterior mandible.

Bone Regeneration↗

PubMedDate not supplied

Quantitative evaluation of bone density using the Hounsfield index.

PURPOSE: The primary aims of this retrospective study were to: (1) evaluate bone quality in different segments of the edentulous jaw and correlate it with demographic data and (2) establish a quantitative and objective assessment of bone quality based on the Hounsfield scale. MATERIALS AND METHODS: One hundred one randomly selected computerized tomographic (CT) scans were used for the analysis. Edentulous segments ranging from 10 to 30 mm were selected for evaluation, and the findings were analyzed and correlated to demographics. Implant recipient sites were evaluated visually for bone classification by 2 independent examiners. The same sites were subsequently evaluated digitally using the Hounsfield scale, and the results were correlated with the visual classification. RESULTS: The 4 quadrants of the mouth displayed Hounsfield unit (HU) values ranging from -240 HU to 1,159 HU. The highest unit/mean density value (559 +/- 208 HU) was found in the anterior mandible, followed by 517 +/- 177 HU for the anterior maxilla, 333 +/- 199 HU for the posterior maxilla, and 321 +/- 132 HU for the posterior mandible. There was no association between the Hounsfield value and density and age or gender. When subjective bone quality was correlated to Hounsfield index findings, only the relationship between HU and type 4 bone was found to be significant. CONCLUSIONS: Knowledge of the Hounsfield value as a quantitative measurement of bone density can be helpful as a diagnostic tool. It can provide the implant surgeon with an objective assessment of bone density, which could result in modification of surgical techniques or extended healing time, especially in situations where poor bone quality is suspected.

Adolescent↗