Faculty Bibliography

Endothelial progenitor cells from the pulp of milk teeth were isolated for use in clinical applications and tissue engineering. Normal deciduous teeth from children of 7 to 8 years of age, which more than half the tooth root was extracted, were selected from the dental centre. Cells from enzyme treated pulps were cultured and cells resulting from the fifth and eight subculture were combined for cell surface marker determination experiments. Cells were positive for CD34 marker with a total of 99/45%, determined by flowcytometry. Cells also demonstrated alkaline phosphatase (ALP) activity. From the developmental point of view, stem cells from the dental pulp seem to have derived from the neural crest, which our findings technically support this theory. In essence mobile progenitor cells from bone marrow of endothelial origin could also play a significant role in the derivation of dental pulp stem cells

Mesothelial progenitor cells have been reported to reside in either the monolayer of mesothelium, submesothelium or within the peritoneal cavity as free floating cells. As a putative plasticity has been reported for the mesothelial progenitor cells and considering the potential implications of the establishment of a novel resource of stem/progenitor cells in gene and cell therapeutics and tissue engineering, we conducted an in vivo tracking of transplanted mesothelial cells. In order to induce immunodeficiency, the recipient mice were treated with 32 mg kg(-1) of daily Cyclosporine. On days 14, 30 and 60 post transplantation, brain, heart, skeletal muscle and lung tissues were screened by a modified FISH method directed to the Y chromosome of donor cells. Fluorescence harboring cells were analyzed by flow cytometry and fluorescent microscopy. The data confirmed by PCR, demonstrated the existence morphology alteration of the donor cells in various organs of the recipient mice, notably in the skeletal muscle and lung and less in the heart and brain. Immunostaining of recovered cells from the nervous recipient tissues suggests differentiation of mesothelial cells in the new microenvironment

This in vitro study used two resin cements to evaluate the microleakage of CEREC 3D restorations. An mesio-occluso-distal-lingual (MODL) onlay preparation was placed on an ivorine premolar tooth. Sixty elastomeric impressions of this preparation were used to fabricate resin dies. Imaging propellant was applied to the resin dies. Optical impressions were taken with the CEREC 3 and the CEREC 3D software and used to design and mill 60 onlays. The reliability coefficient was alpha = 0.76 with an examiner agreement rate of 96.4%. Restorations cemented with posterior composite demonstrated a mean microleakage value of 1.46 mm (SD+/- 1.64); by contrast, those restored with dual-cure cement reported a mean microleakage value of 0.21 mm (SD+/-0.57). The difference in microleakage was very highly significant (alpha = 0.001). Posterior composite CEREC 3D restorations cemented with the dual-cure cement showed significantly less microleakage compared to those cemented with posterior composite

A multidisciplinary approach is generally required in the treatment of patients who present with missing and malpositioned teeth to achieve an esthetic and functional outcome. Treatment of a patient with congenitally transposed canines, missing central incisors, and peg-shaped lateral incisors using a multidisciplinary approach is presented

OBJECTIVES: The objective of this pilot study was to investigate the feasibility of periodontal ligament (PDL) generation on an implant surface by approximating a tooth-to-implant contact using orthodontics. METHODS: Maxillary second premolars of six beagle dogs were extracted bilaterally. After 2 weeks of healing, hydroxyapatite (HA) coated titanium implants, 5 mm in length and 3.3 mm in diameter, were placed in the extraction sites. One side of the arch was used as control. Orthodontic tooth movement was initiated following implant placement to tip the first premolar roots into contact with the implant. This was achieved in 4-6 weeks as confirmed radiographically. Tooth-to-implant contact was maintained for further 6 weeks after which time, teeth were separated from implant contact orthodontically. After further 2 weeks of stabilization, the animals were sacrificed. Samples were analyzed by Faxitron radiographs before histology. Histology samples were prepared with Stevenel's Blue and Van Gieson stain and were subjected to polarized light microscopy. RESULTS: Histologic analysis revealed transfer and formation of PDL-like structure with formation of cellular cementum on the implant surfaces, in four out of six animals, where tooth-to-implant contact had been achieved. Direct bone-to-implant contact was noted in the areas coronal to the PDL-like tissue, an important sign to distinguish between PDL-like tissue and connective tissue that could originate from the coronal portion of a failing implant. Additionally, at the site of contact, the implant surface revealed some resorption of the HA coating. CONCLUSION: An animal model was established in which the proximity of tooth-to-implant contact lead to partial generation of PDL on a bioactive implant surface in four out of six animals.

STATEMENT OF PROBLEM: One of the most important criteria for the clinical acceptability and longevity of cast restorations is marginal adaptation. However, there is limited information on the accuracy of commonly practiced evaluation techniques. PURPOSE: This study assessed the effect of preparation design on marginal adaptation. In addition, sensitivity and specificity of clinical evaluations of marginal adaptations of cast restorations were assessed and compared to stereomicroscopy. MATERIAL AND METHODS: Three Ivorine molar teeth of differing designs were prepared: (1) a complete crown preparation with a chamfer finish line, (2) a complete crown preparation with a buccal shoulder and beveled finish line, and (3) a three-quarter crown preparation with proximal boxes and beveled finish line. Twenty-four castings (n = 8) were prepared (Ney technique casting metal). Twelve circumferential sites were identified for examination on each casting using a stereomicroscope, which was interpreted using software (Bioquant 98). The clinical examinations included explorer examination to detect marginal gap by tactile feel, followed by examination with a disclosing media (GC FitChecker). Chi-square tests of independence were used to evaluate the effect of preparation design and compare agreement between examination methods for detection of marginal gap size of greater than or equal to 30 microm (alpha=.05). RESULTS: The overall marginal adaptation of preparation designs was not significantly different. Results of explorer examination at 30-microm sensitivity and specificity were 46% and 97%, respectively. Similar values for disclosing media at 30 microm were 12% sensitivity and 97% specificity. The overall percent agreement with the stereomicroscope using the explorer was 58.3%, with 23.6% correct acceptance rate and 34.7% correct rejection rate. With respect to detection of marginal fit, the combination of disclosing material with explorer data did not yield significantly improved results (59.4%), as compared to explorer alone. A receiver operator characteristic curve yielded satisfactory sensitivity (0.8) and specificity (0.9) at a gap size value of 124 microm. CONCLUSION: Within the limitations of this study, the preparation design did not significantly affect the marginal adaptation. Clinical detection, with similar sensitivity and specificity as the stereomicroscope, occurred at marginal openings greater than or equal to 124 microm. Therefore, commonly used clinical evaluation techniques using an explorer and disclosing media may be inadequate for assessments of marginal accuracy