[Comparative research for micro-push-out bond strengths of glass fiber posts treated by poly-dopamine or silane coupling agent].

OBJECTIVE: To evaluate the micro-push-out bond strengths of prefabricated glass fiber posts with poly-dopamine functionalized to root dentin using resin cements, contrasted with silane treatment. METHODS: In the study, 30 glass fiber posts were randomly divided into 3 groups (10 posts in each group) for different surface treatments. Group 1, treated with poly-dopa; Group 2, treated with silane coupling agent for 60s; Group 3, no surface treatment (Control group). The 30 extracted human, single-rooted teeth were endodontically treated and a 9 mm post space was prepared in each tooth with post drills provided by the manufacturer. Following post cementation, the specimens were stored in distilled water at 37 °C for 7 days. The micro-push-out bond strengths were tested using a universal testing machine (0.5 mm/min), and the failure modes were examined with a stereomicroscope. The data of the three groups were statistically analyzed using the one-way ANOVA test(α= 0.05). RESULTS: The bond strengths were (7.909 ± 1.987) MPa for Group 1, (5.906 ± 0.620) MPa for Group 2, and 4.678 ± 0.910 MPa for Group 3. The bond strength of poly-dopamine group was significantly higher than that of the silane group (P<0.05). CONCLUSION: Contrasted with silane treatment, surface poly-dopamine functionalization was confirmed to be a more reliable method for improving the bond strength of resin luting agents to fiber posts.

Effect on the bond strengths of glass fiber posts functionalized with polydopamine after etching with hydrogen peroxide.

UNLABELLED: This paper evaluated the push-out bond strengths of glass fiber posts with poly-dopamine (poly-dopa) functionalized after etching with H2O2. Forty extracted human, single-rooted teeth were endodontically treated and a 9-mm post space was prepared in each tooth with post drills provided by the manufacturer. Specimens were randomly assigned into four groups (n=10 per group), depending on post surface treatment used: group C (control); group D (poly-dopa); group H (H2O2); and group HD (H2O2+poly-dopa). The push-out test was performed using a universal testing machine. RESULTS: Bond strengths (MPa) were as follows: 4.678±0.911 (group C); 7.909±1.987 (group D); 6.519±0.893 (group H); and 9.043±1.596 (group HD). The bond strength of the resin cement to posts functionalized with poly-dopa was not affected by H2O2 pre-treatment, while conditioning using H2O2+poly-dopa resulted in higher bond strengths than H2O2 treatment only. Compared to H2O2 treatment, the bond strength of poly-dopa conditioning was superior.

[Class III surgical patients facilitated by accelerated osteogenic orthodontic treatment].

OBJECTIVE: To evaluate the treatment time and the anterior and posterior teeth movement pattern as closing extraction space for the Class III surgical patients facilitated by accelerated osteogenic orthodontic treatment. METHODS: There were 10 skeletal Class III patients in accelerated osteogenic orthodontic group (AOO) and 10 patients in control group. Upper first premolars were extracted in all patients. After leveling and alignment (T2), corticotomy was performed in the area of maxillary anterior teeth to accelerate space closing.Study models of upper dentition were taken before orthodontic treatment (T1) and after space closing (T3). All the casts were laser scanned, and the distances of the movement of incisors and molars were digitally measured. The distances of tooth movement in two groups were recorded and analyzed. RESULTS: The alignment time between two groups was not statistically significant. The treatment time in AOO group from T2 to T3 was less than that in the control group (less than 9.1 ± 4.1 months). The treatment time in AOO group from T1 to T3 was less than that in the control group (less than 6.3 ± 4.8 months), and the differences were significant (P < 0.01). Average distances of upper incisor movement (D1) in AOO group and control group were (2.89 ± 1.48) and (3.10 ± 0.95) mm, respectively. Average distances of upper first molar movement (D2) in AOO group and control group were (2.17 ± 1.13) and (2.45 ± 1.04) mm, respectively.No statistically significant difference was found between the two groups (P > 0.05). CONCLUSIONS: Accelerated osteogenic orthodontic treatment could accelerate space closing in Class III surgical patients and shorten preoperative orthodontic time. There were no influence on the movement pattern of anterior and posterior teeth during pre-surgical orthodontic treatment.