Background:The aim of the present study was to determine the most effective oral hygiene method in fixed orthodontic patients. Methods: A total of 125 patients who had recently started their orthodontic treatment and had not received oral hygiene instructions were randomly assigned to 5 groups (n = 25): verbal instructions (V), verbal instructions plus pamphlet (V + P), verbal instructions plus video film (V + F), verbal instructions plus the use of disclosing agents (V + D), and pamphlet plus the use of disclosing agents (P + D). One week after the installation of orthodontic appliance, plaque index (PI) and gingival index (GI) were recorded and oral hygiene instructions were provided. One week and 4 weeks after oral hygiene instructions, PI and GI were recorded again. Results: PI and GI showed significant decreases in 5 groups after 1 week and 4 weeks (P ˂ 0.05). No statistically significant differences were detected between the 5 study groups in terms of plaque reduction after one week. However, after 4 weeks PI values were significantly lower in V + D group compared to P + D group. Regarding GI, V + D method resulted in a significantly lower GI than P + D after 1 week and 4 weeks. Conclusions: To sum up, all the oral hygiene motivation methods applied in this study can be effective in decreasing PI and GI. However, it appears that the best way is the verbal oral hygiene instruction plus the use of disclosing agents.

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Implant-retained mandibular ball-supported and bar-supported overlay dentures are the two most common treatment options for the edentulous mandible. The superior option in terms of strain distribution should be determined. The three-dimensional model of mandible (based on computerized tomography scan) and its overlying implant-retained bar-supported and ball-supported overlay dentures were simulated using SolidWorks, NURBS, and ANSYS Workbench. Loads A (60 N) and B (60 N) were exerted, respectively, in protrusive and laterotrusive motions, on second molar mesial, first molar mesial, and first premolar. The strain distribution patterns were assessed on (1) implant tissue, (2) first implant-bone, and (3) second implant-bone interfaces. Protrusive: Strain was mostly detected in the apical of the fixtures and least in the cervical when bar design was used. On the nonworking side, however, strain was higher in the cervical and lower in the apical compared with the working side implant. Laterotrusive: The strain values were closely similar in the two designs. It seems that both designs are acceptable in terms of stress distribution, although a superior pattern is associated with the application of bar design in protrusive motion.

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Background. Stem cells have contributed to the development of tissue-engineered-based regenerative periodontal therapies. In order to find the best stem cell sources for such therapies, the biologic properties of stem cells isolated from periodontal ligaments (PDL) of deciduous (DePDLSC) and permanent (PePDLSC) teeth were comparatively evaluated. Methods. PDL stem cells were isolated from six sound fully erupted premolars and six deciduous canines of healthy subjects. In vitro biologic characteristics such as colony formation, viability, stem cell marker identification and osteogenic differentiation (using alkaline phosphatase analysis and Alizarin red staining) were comparatively assessed using one-way ANOVA and post hoc Tukey tests using SPSS 13.0. Results. Stem cell populations isolated from both groups were CD105+ and CD90+ and CD45‒. No statistically significant differences were found in stem cell markers, colony formation and viability. Both groups were capable of osteogenic differentiation. However, alkaline phosphatase activity test showed a statistically significant difference, with PePDLSC exhibiting higher alkaline phosphatase activity (P=0.000). No statistically significant difference was seen in quantitative alizarine red staining (P=0.559). Conclusion. Mesenchymal stem cells of PDL could successfully be isolated from permanent and deciduous teeth. A minor difference was observed in the osteogenic properties of the two cell types, which might affect their future clinical applications.