Adjunctive controlled intrusion of the maxillary first molar using orthodontic miniscrews.

In the absence of the mandibular first molar, there is corresponding supra-eruption of the maxillary first molar, which can lead to occlusal interferences compromising the space available for restoration with a prosthesis. In this case report, the maxillary left first molar intrusion has been discussed with the use of two miniscrews. A 28-year-old female reported with a missing mandibular left first molar and wanting to replace it with a dental implant. The patient presented with a Class I skeletal relation, mild proclination of the anteriors and occlusal contacts. The maxillary first molar had erupted by >4 mm beyond the occlusal plane, thereby reducing the space available for placement of a lower prosthetic crown. After 5 months of intrusion, the desired occlusal clearance was achieved, and impressions were recorded. For retention, the patient was given an upper clear vacuum retainer and the crown was placed on the implant.

Gingiva Mesenchymal Stem Cells Normoxic or Hypoxic Preconditioned Application Under Orthodontic Mechanical Force on Osterix, Osteopontin, and ALP Expression.

OBJECTIVES: The aim of this article was to investigate Osterix, ALP, and osteopontin expression in the compression and tension sides of alveolar bone after the application of normoxic/hypoxic-preconditioned GMSCs in rabbits (Oryctolagus cuniculus) induced with OMF. MATERIALS AND METHODS: Forty-eight healthy, young male rabbits were divided into four groups: [-] OMF; [+] OMF; OMF with GMSCs normoxic-preconditioned; and OMF and GMSCs hypoxic-preconditioned. The central incisor and left mandibular molar in the experimental animals were moved, the mandibular first molar was moved mesially using nickel titanium (NiTi) and stainless steel ligature wire connected to a 50 g/mm2 light force closed coil spring. Allogeneic application of normoxic or hypoxic-preconditioned GMSCs was used in as many as 106 cells in a 20 µL phosphate buffered saline single dose and injected into experimental animals' gingiva after 1 day of OTM. On days 7, 14, and 28, all experimental animals were euthanized. Osterix, ALP, and osteopontin expressions were examined by immunohistochemistry. RESULTS: Osterix, ALP, and osteopontin expressions were significantly different after allogeneic application of hypoxic-preconditioned GMSCs than normoxic-preconditioned GMSCs in the tension and compression of the alveolar bone side during OMF (p < 0.05). CONCLUSION: Osterix, ALP, and osteopontin expressions were significantly more enhanced post-transplantation of GMSCs with hypoxic-preconditioning than after transplantation of normoxic-preconditioned GMSCs in rabbits (O. cuniculus) induced with OMF.

Receptor Activator of Nuclear Factor-Kappa Ligand and Osteoprotegerin Expressions on Hyperglycemic Wistar Rats (Rattus Novergicus) During Orthodontic Tooth Movement

Abstract Objective: To investigate the differences of receptor activator of nuclear factor-κB ligand (RANKL) and Osteoprotegerin (OPG) expressions between normoglycemic and hyperglycemic Wistar rats (Rattus Novergicus) during Orthodontic Tooth Movement (OTM). Material and Methods: This study was true experimental with post-test group only. Thirty-two healthy male Wistar rats, weighted around 200-250 grams, 12-20 weeks old, were used as OTM animal study. They were divided into 2 groups (n=16), normoglycemic rats (normal blood glucose 80-120 mg/dl) and hyperglycemic rats (>250 mg/dl) induced by Streptozotocin with a dose of 30 mg in PBS injection intraperitoneally. A NiTi closed coil spring was mounted between maxillary first molar and incisors with the light force 10gf/mm2 in both groups to induce OTM. The studied animals were then terminated on days 1, 3, 6, and 9, respectively, and premaxilla was extracted. RANKL and OPG expression were examined utilizing immunohistochemistry (IHC) analysis. One-way ANOVA and Tukey HSD (p<0.05) were utilized to analyze the differences in the expression of RANKL and OPG between groups. Results: The hyperglycemic group on day 1, 9 rats showed a significant increase in the expression of RANKL, whereas OPG expression decreased significantly on days 1, 3, and 9. Conclusion: There was a significant increase of RANKL expression and a decrease of OPG expression in hyperglycemic rats as documented immunohistochemically.

Cytotoxicity of Calcium Hydroxide on Human Umbilical Cord Mesenchymal Stem Cells

Abstract Objective: To examine the cytotoxicity of calcium hydroxide on human umbilical cord mesenchymal stem cells (HUCMSC) to understand the characteristics for use in regenerative dentistry procedures especially regenerative endodontics. Material and Methods: HUCMSC was isolated, cultured, and confirmed by flow cytometry. The biological characteristics, such as cell morphology, proliferation, and protein expression, were screened. To check the cytotoxicity, HUCMSC was cultured and divided into two groups, the control group (cultured in minimum essential medium (MEM) alpha) and calcium hydroxide group (cultured in MEM alpha and calcium hydroxide). Methyl-thiazole-tetrazolium (MTT) assay was done on different concentrations of calcium hydroxide (0.39 to 25 µg/mL) and the cells were observed and counted. One-way ANOVA test was used with a significance level set at 5%. Results: Flow cytometric analysis confirmed positive of CD73, CD90, CD105, negative of CD45 and CD34. A significant difference was found between the concentration of 6.25 and 3.125 µg/mL (p=0.004). There was no significant difference among 6.25, 12.5 and 25 µg/mL concentrations. There was also no significant difference among 0.39, 0.78, 1.56, and 3.125 µg/mL concentrations. Conclusion: Even though calcium hydroxide is a medicament of choice in clinical endodontics, it decreases the viability of HUCMSC. The lower the concentration of calcium hydroxide, the higher the viability of HUCMSC.