Two-dimensional facial measurements for anterior tooth selection in complete denture treatment.

Purpose: Anterior tooth selection is one of the most challenging parts in determining tooth dimensions and critical to the aesthetic aspect of the complete denture treatment. However, the methods for anterior tooth size selection using facial measurements are still controversial. This study aimed to investigate the relationship between dental measurements and facial measurements, and to establish the anterior tooth size prediction equation using facial dimensions in the Thai population for the complete denture treatment. Materials & methods: One hundred and twenty-five Thai participants (53 men and 72 women) aged 18-35 years old with Angle class I occlusion, did not currently undergo orthodontic treatment, had normal alignment on the maxillary anterior teeth, no attrition, abrasion, proximal restoration or prosthesis were investigated. One frontal facial photograph and one dental photograph of each participant were made using an image analyzing program (ImageJ version 1.53b) to measure the six horizontal facial distances, five vertical facial distances and three dental distances as 2D facial and dental measurements. Pearson correlation and multiple linear regression analysis were performed. Results: The difference of facial and dental measurements between men and women were statistically significant (P < .001). Interpupillary width, interlateral canthal width, intercommissural width and bizygomatic width were correlated to dental measurements in both sexes. Intermedial canthal width and lip thickness were correlated to dental measurements in women. Face length and lateral canthus to lower border of face were correlated to dental measurements in men. Prediction equations of each dental measurement were established using only horizontal facial dimension and using both horizontal and vertical facial dimensions. Conclusions: Facial and dental dimensions are sex-dependent. Facial measurements can be applied in a regression equation to predict dental measurements. Adding vertical dimensions of facial measurements to the prediction equations of anterior tooth size selection results in a higher R squared to 0.444. This finding can be used as a tool for anterior tooth size selection in the complete denture treatment.

Induction of Osseointegration by Nacre in Pigs.

Nacre is a biomaterial that has shown osteoinductive and osteoconductive properties in vitro and in vivo. These properties make nacre a material of interest for inducing bone regeneration. However, information is very limited regarding the introduction of nacre to dental implant surgery for promoting osteogenesis. This study investigated the potential of nacre powder for peri-implant bone regeneration in a porcine model. Ninety-six dental implants were placed into the tibia of twelve male domestic pigs. The dental implants were coated with nacre powder from the giant oyster before implantation. Implantations without nacre powder were used as control groups. Euthanization took place at 2, 4 and 6 weeks after implantation, after which we measured bone-to-implant contact (BIC) and bone volume density (BVD) of the implanted bone samples using micro-computed tomography (micro-CT), and examined the histology of the surrounding bone using histological sections stained with Stevenel's blue and Alizarin red S. The micro-CT analyses showed that the BIC of dental implantations with nacre powder were significantly higher than those without nacre powder, by 7.60%. BVD of implantations with nacre powder were significantly higher than those without nacre powder, by 12.48% to 13.66% in cortical bone, and by 3.37% to 6.11% in spongy bone. Histological study revealed more peri-implant bone regeneration toward the surface of the dental implants after implantation with nacre powder. This was consistent with the micro-CT results. This study demonstrates the feasibility of using nacre to promote peri-implant bone regeneration in dental implantation.

Shotgun proteomics analysis of proliferating STRO-1-positive human dental pulp cell after exposure to nacreous water-soluble matrix.

INTRODUCTION: For dental treatment, dentin regeneration is required after a tooth injury with dental pulp exposure. The effects of the water-soluble matrix (WSM) extracted from the nacreous layer of the bivalve Pinctada maxima on human dental pulp cells in vitro were challenging and useful for clinical application. MATERIAL AND METHODS: The biological activity of the STRO-1-positive human dental pulp cells in response to WSM compared to Dulbecco's modified Eagle medium (DMEM) as a normal control was monitored. The cell survival rate was analyzed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Proteomic profiles among inducers and noninducers with time dependency were compared by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis combined with liquid chromatography-tandem mass spectrometry (GeLC-MS/MS). RESULTS: The human dental pulp cells cultured in nacreous WSM exhibited higher relative cell viability than those in DMEM with similar morphological appearance. Significant changes were found in the relative abundance of 44 proteins in cells after exposure to WSM for 2 weeks. They play a role in cell adhesion, cell proliferation, metabolic process, signal transduction, stress response, transcription, translation, and transport. CONCLUSION: These results indicate that WSM of P. maxima has the ability to induce proliferation of human dental pulp cells. CLINICAL RELEVANCE: This finding initiated the study to evaluate the suitability of nacre as biomaterial for dentistry.

Morinda citrifolia leaves enhance osteogenic differentiation and mineralization of human periodontal ligament cells.

This present study investigated the potential of Morinda citrifolia leaf aqueous extract to induce osteogenic differentiation and matrix mineralization of human periodontal ligament (hPDL) cells. Human periodontal ligament cells were cultured in complete medium, ascorbic acid with ß-glycerophosphate, or Morinda citrifolia leaf aqueous extract. Morinda citrifolia leaf aqueous extract significantly increased alkaline phosphatase activity compared to culturing in complete medium or ascorbic acid with ß-glycerophosphate. Matrixcontaining mineralized nodules were formed only when the cells were cultured in the presence of Morinda citrifolia leaf aqueous extract. These nodules showed positive alizarin red S staining and were rich in calcium and phosphorus according to energy dispersive X-ray analysis. In conclusion, Morinda citrifolia leaf extract promoted osteogenic differentiation and matrix mineralization in human periodontal ligament cells, a clear indication of the therapeutic potential of Morinda citrifolia leaves in bone and periodontal tissue regeneration.

Morinda citrifolia leaves enhance osteogenic differentiation and mineralization of human periodontal ligament cells.

This present study investigated the potential of Morinda citrifolia leaf aqueous extract to induce osteogenic differentiation and matrix mineralization of human periodontal ligament (hPDL) cells. Human periodontal ligament cells were cultured in complete medium, ascorbic acid with ß-glycerophosphate, or Morinda citrifolia leaf aqueous extract. Morinda citrifolia leaf aqueous extract significantly increased alkaline phosphatase activity compared to culturing in complete medium or ascorbic acid with ß-glycerophosphate. Matrixcontaining mineralized nodules were formed only when the cells were cultured in the presence of Morinda citrifolia leaf aqueous extract. These nodules showed positive alizarin red S staining and were rich in calcium and phosphorus according to energy dispersive X-ray analysis. In conclusion, Morinda citrifolia leaf extract promoted osteogenic differentiation and matrix mineralization in human periodontal ligament cells, a clear indication of the therapeutic potential of Morinda citrifolia leaves in bone and periodontal tissue regeneration.

Alveolar bone regeneration by implantation of nacre and B-tricalcium phosphate in guinea pig.

PURPOSE: To investigate alveolar bone regeneration after nacre implantation in comparison to ß-tricalcium phosphate (ß-TCP) for the potential application to bone grafting. MATERIAL AND METHODS: The rod-shaped, 2 × 2 mm in diameter and length, implanted materials were prepared from nacre particles of the giant oyster (Pinctada maxima), and ß-TCP (Chronos; Synthes, Switzerland) particles. Bilateral drilling procedures were performed in 10 male guinea pigs in the mandible. Eight animals were implanted with nacre and ß-TCP rods on each side of the mandibles. Two animals were sham operated. The animals were sacrificed after 30 and 60 days during the healing period. Decalcified histological sections of the mandibles were stained with azan stain. RESULTS: Alveolar bone regeneration in surgically created defects was more effective in material-implanted groups than in the sham-operated group. The nacre-implanted group exhibited the highest new bone formation, followed by the ß-TCP-implanted group and the sham-operated group, respectively. Large space filling with some fibrous tissue in central region of the defected site in ß-TCP-implanted and sham-operated mandibles was noted. CONCLUSION: The results demonstrate the feasibility of using nacre as an alternative bone graft material.

Potential induction of bone regeneration by nacre: an in vitro study.

PURPOSE: Because of limitations of autogenous grafts, alternative bone substitute material was investigated for its capacity in promoting bone formation. This study compared the osteogenic effects of nacre (mother of pearl) and beta-tricalcium phosphate (ß-TCP). MATERIALS AND METHODS: Human bone cells (HBCs) were obtained from the culture of bone tissues after orthognathic surgery. The HBCs were cocultured with nacre chips of the giant oyster Pinctada maxima and with ß-TCP particles for 1, 2, 3, and 4 weeks. Cells of each week specimens were used to study alkaline phosphatase (ALP), bone sialoprotein (BSP), and osteocalcin (OC) gene expression by noncompetitive reverse-transcriptase polymerase chain reaction and to study BSP synthesis by means of an immunocytochemical technique in conjunction with fluorescent microscopy. RESULTS: Reverse-transcriptase polymerase chain reaction demonstrated stronger expression levels of ALP mRNA in HBCs cocultured with the nacre chips than those with ß-TCP at weeks 2 and 4. BSP gene expression levels in HBCs with nacre were more intense compared with ß-TCP at weeks 3 and 4. Although the OC gene expression level in HBCs with ß-TCP was higher than those with nacre at week 2, the expression was not different at weeks 3 to 4. Immunocytochemical study revealed that BSP synthesis were presented in the nacre and ß-TCP from week 2 and decreased toward week 4. CONCLUSION: This study indicated that nacre promotes ALP, BSP, and OC gene expression.

Induction of type I collagen and osteocalcin in human dental pulp cells by retinoic acid.

Retinoic acid has been known to play a key role in the regulation of bone cell differentiation and function. The effects of retinoic acid on human dental pulp cells, which contain several characteristics similar to those of bone cells, has yet to be elucidated extensively. The effects of retinoic acid on human dental pulp cells in terms of type I collagen and osteocalcin induction were investigated in vitro. Dental pulp cells obtained from the teeth of young patients (age between 18-22 years) were cultured and subsequently treated with various concentrations of retinoic acid (0, 10(-7), 10(-6), 10(-5) M) in serum-free DMEM. At different time intervals (8, 12 and 24 hours), the levels of type I collagen and osteocalcin secreted were determined using Type I Procollagen C-Peptide and Gla-type Osteocalcin EIA kits, respectively. Induction effects were evaluated using analysis of variance and the Duncan's multiple rank test. Retinoic acid at concentrations of 10(-5), 10(-6), 10(-7) M was able to induce type I collagen and osteocalcin production in human dental pulp cells within 12 hours of exposure. Dose-dependent induction was observed only after 24 hours. A two-fold increase in osteocalcin level was detected after exposed to 10(-5) M retinoic acid within 24 hours. Our data suggest that retinoic acid at concentrations of 10(-5), 10(-6), 10(-7) M has the ability to induce type I collagen and osteocalcin secretions in human dental pulp cells in vitro.

Effect of fluoride on human dental pulp cells in vitro.

Human dental pulp cells were cultured in fluoride containing medium of various concentrations (0, 1, 2, 5, 10, 20, 25, 30, 40, 50, 60 and 80 ppm) in order to study the biological effect on the cells' proliferation and alkaline phosphatase (ALP) activities. It was found that fluoride at 5 ppm concentration significantly stimulated cell proliferation and ALP activity between 24 and 48 hours after exposure whereas at higher concentrations (40 - 80 ppm), fluoride significantly inhibited cell growth and ALP activity after 48 hours (Student's t test). The maximum effect was around 80 ppm. These observations suggest that fluoride, if used at a low concentration, may be a useful therapeutic agent for the treatment of pulpal disease by means of stimulating the proliferation and differentiation of dental pulp cells. At higher concentrations, it will have negative effects on this kind of cell.

Effects of lead on the proliferation, protein production, and osteocalcin secretion of human dental pulp cells in vitro.

Teeth have been recognized as providing a useful long-term record of lead (Pb2+) uptake. However, information regarding the effects of lead on dental pulp tissue cells that foster dentinogenesis is scarce. This study investigated the effects of lead on dental pulp tissue using human dental pulp fibroblasts in vitro. Dental pulp cells from the teeth of young patients (aged 17-24 years) were cultured and subsequently treated with lead glutamate. It was shown that, in serum-free conditions, all the tested concentrations of lead (4.5 x 10(-5) M, 4.5 x 10(-6) M, and 4.5 x 10(-7) M) significantly increased pulpal cell proliferation. In the presence of 2% fetal bovine serum, increasing cell proliferation was observed only after exposure to a lead concentration of 4.5 x 10(-5) M. However, protein, procollagen type I, and osteocalcin productions were significantly decreased. The alteration of cell population and protein production of affected human dental pulp shown in this study are toxic effects of the lead.