The effects of food-simulating liquids (FSLs) on the microhardness and surface roughness: Luna (LN, conventional nanohybrid), Aura Bulk Fill (AB, bulk-fill composite), and Stela Automix (SA, self-cured composite) were evaluated. The materials were exposed to air as control, artificial saliva and three FSLs: 50% ethanol-water solution, 0.02N citric acid, and heptane-over different time intervals to compare their performance. Microhardness and surface roughness were measured at baseline, seven days, and 30 days after immersion. Two-way ANOVA revealed significant interactions between FSLs and materials for both microhardness and surface roughness (p<0.001). All materials showed a decrease in microhardness and an increase in surface roughness over time, except when exposed to air. LN exhibited the highest microhardness and lowest surface roughness, while SA demonstrated the lowest microhardness and the highest surface roughness in all FSLs. SA's surface roughness decreased in citric acid, potentially due to its lower filler content, which may result in a less durable surface. Ethanol and citric acid had the most detrimental effects on the microhardness of all materials, while heptane caused the most significant surface roughness changes in SA. These results highlight the material-specific responses to FSLs, with important implications for material selection and restoration longevity in clinical practice.

OBJECTIVE: This study examined bone microstructure restoration after rapid maxillary expansion (RME) with and without corticotomy over multiple retention periods. METHODS: Eighteen male Dorper sheep were randomly distributed into three groups (n = 6 each group): group 1, RME with corticotomy on the buccal and palatal sides; group 2, conventional RME treatment; and group 3, no treatment. Post-RME, trabecular bone microstructure and new bone formation were evaluated by using microcomputed tomography (microCT) and histomorphometry after a 4- or 12-week retention period. Intergroup differences in bone quality and bone remodeling were analyzed by using two-way analysis of variance with Bonferroni post-hoc test. RESULTS: The bone volume fraction (bone volume [BV]/total volume [TV]) values relative to the control in groups 1 and 2 were 54.40% to 69.88% after the 4-week retention period and returned to approximately 80% after the 12-week retention period. The pooled BV/TV values of the banded teeth in groups 1 and 2 were significantly lower than those of the control after the 4-week retention period (p < 0.05). However, after the 12-week retention period, the pooled BV/TV values in group 2 were significantly lower than those in groups 1 and 3 (p < 0.05). Histomorphological analysis showed that the new bone formation area in group 1 was approximately two to three times of those in group 2 and control. CONCLUSIONS Corticotomy significantly enhanced the restoration of bone quality after the retention periods for banded teeth. This benefit might result from the increased new bone formation after corticotomy.

OBJECTIVE: This study aimed to explore the usefulness of adjunctive buccal and palatal corticotomy for adult maxillary expansion in an animal model using cone-beam computed tomography (CBCT). METHODS: Twelve adult sheep were randomly divided into two groups (each n = 6): a control group, where no treatment was administered, and a treatment group, where buccal and palatal corticotomy-assisted maxillary expansion was performed. CBCT scans were taken before (T1) and after (T2) treatment. Differences in all transverse dental and alveolar dimensions, alveolar width at crest level, hard palate level, horizontal bone loss, interdental cusp width and inter-root apex were assessed using Wilcoxon signed-rank and Mann-Whitney U-tests. Kruskal-Wallis tests and pairwise comparisons were used to detect the significance of differences among the inter-premolar and inter-molar widths. RESULTS: CBCT data revealed significant changes in all transverse dental and alveolar dimensions. The mean interpremolar alveolar width showed an increase of 2.29 to 3.62 mm at the hard palate level, 3.89 to 4.38 mm at the alveolar crest level, and 9.17 to 10.42 mm at the buccal cusp level. Dental changes in the vertical dimension were not significant. CONCLUSIONS: Our findings based on an adult animal model suggest that adjunctive buccal and palatal corticotomy can allow for both skeletal and dental expansion, with the amount of dental expansion exceeding that of skeletal expansion at alveolar crest and hard palate levels by two and three folds, respectively. Therefore, this treatment modality is potential to enhance the outcomes of maxillary expansion in adults.
Adult* ; Animals* ; Cone-Beam Computed Tomography ; Humans ; Models, Animal* ; Palatal Expansion Technique* ; Palate, Hard ; Sheep ; Vertical Dimension