Simvastatin encapsulated in exosomes can enhance its inhibition of relapse after orthodontic tooth movement.

INTRODUCTION: Relapse after orthodontic treatment is a major clinical issue in the dental field. Studies indicate that simvastatin may, to some extent, decrease the rate and magnitude of relapse status. Recent evidence demonstrated that exosome-based drug delivery has a broad prospect of clinical application. Hence, this study investigates whether simvastatin encapsulated in exosomes can inhibit relapse after orthodontic tooth movement (OTM). METHODS: Periodontal ligament stem cells (PDLSCs) and their exosomes (PDLSCs-Exo) were isolated and identified. Exosomal simvastatin was obtained by co-incubation of simvastatin and PDLSCs-Exo. An OTM rat model was established. During the relapse period, rats' local alveolar bone was injected with simvastatin, PDLSCs-Exo, and exosomal simvastatin to examine the effect on relapse. Finally, we analyzed the influence of exosomal simvastatin on osteogenesis at the molecular and histologic levels. RESULTS: PDLSCs and PDLSCs-Exo were successfully extracted and characterized by multiple means. Simvastatin encapsulated in exosomes can increase the solubility of the drug. Exosomal simvastatin can enhance its inhibition of relapse after OTM in the rat model. The expression level of osteogenic-related genes and proteins in the exosomal simvastatin group is higher than in other groups. Histologic analysis showed a reduction of bone-resorptive lacunae in the exosomal simvastatin group. CONCLUSIONS: Encapsulating simvastatin into the exosomes derived from PDLSCs can improve simvastatin solubility and enhance the inhibition effect of relapse in the rat model of OTM. Notably, local injection of PDLSCs-Exo alone can also block the relapse after OTM.

The bridging and normal dimensions of sella turcica in Yemeni individuals.

OBJECTIVE: This study aimed to evaluate and compare sizes, shapes and bridging of the sella turcica (ST) in Yemeni individuals with different skeletal patterns, genders, and ages, and to assess the association between the linear dimension of ST and gender, age, or skeletal patterns. The standard anatomical structure of ST among Yemeni subjects is still unknown and this study can be considered as the first reference regarding ST of Yemeni individuals. MATERIALS AND METHODS: Cephalogram images for 234 subjects (167 females and 67 males) were traced and classified for groups by gender, age, and dentofacial skeletal patterns. Size, shape, and bridging of ST were assessed. Multivariate ANOVA (MANOVA) analysis was used to detect the interaction between gender, age, and skeletal patterns on ST dimensions. RESULTS: The mean values for length, anteroposterior diameter, and depth of ST were 8.02 ± 1.67, 11.37 ± 1.60, and 8.56 ± 1.26 mm, respectively. A significant difference in length of ST between gender and age stages (p < 0.05) was detected while older subjects revealed a greater anteroposterior diameter than younger subjects (p < 0.05). The morphological variations of ST were observed in 55.6% of samples. No significant association between the shape of ST and skeletal patterns (p > 0.05) was found. CONCLUSIONS: ST bridging was highly prevalent in Yemeni subjects (35.9%). Samples showed a higher rate of complete ST bridging in the three skeletal patterns, Class I (17.1%), Class II (18.9%), and Class III (20%). ST dimensions and shape findings in this study can be used as reference standards for further investigation, including the ST area in the Yemeni population.

Association of congenital missing of maxillary lateral incisors with cervical vertebral body fusions and/or atlas posterior arch deficiency.

To evaluate the association between congenital missing of maxillary lateral incisor (MLI) with cervical vertebral body fusions, posterior arch deficiency, and both anomalies. A total of 64 subjects (24 males and 40 females; mean age 16 ± 4.5 years) were detected to have congenital missing of MLI and selected as a study group. Two hundred and fifty-six subjects (87 males and 169 females, mean age 18.1 ± 3.2 years) were assigned to the control group. In the congenital absence of MLI, 53.7% revealed cervical column body fusion, 11.1% indicated a posterior arch deficiency, and 9.3% showed cervical column body fusion with posterior arch deficiency. Morphological deviations of the cervical column showed significant associations with congenital absence of MLI compared to control group (p < 0.001). There were no significant differences in gender among the study and control groups (p > 0.05). Subjects with congenial MLI tend to have an increased frequency of cervical anomaly.

Morphology, Incidence of Bridging, Dimensions of Sella Turcica, and Cephalometric Standards in Three Different Racial Groups.

This study aims to assess the morphological appearance, incidence of bridging, linear dimensions of sella turcica and establish cephalometric standards in Bosnian, Chinese and Nepalese subjects. This retrospective study examined digital standardized lateral cephalograms of 540 subjects, which consisted of 116 females and 64 males with an age range of 8 to 28 years. The sella morphology, bridging, and size were analyzed on the lateral cephalograms. Steiner's and Rickett's analyses were performed on 270 subjects. Sella turcica presented a normal morphology in most Bosnian (86.7%), and Nepalese (90%) subjects whereas flat-shaped morphology was highly prevalent among Chinese subjects (36.7%). The frequency of full bridging was 7.2%, 2.8%, and 11.7% for Bosnian, Chinese, and Nepalese subjects, respectively. A significant correlation was detected between the length of sella turcica and gender of Bosnian subjects, whereas the size of sella turcica and gender of Chinese and Nepalese subjects were not affected. A direct correlation existed between age and size of sella turcica of Bosnian subjects. A significant correlation was detected between length and diameter of sella turcica and age in Chinese and Nepalese subjects. A statistically significant difference was found in length (P < 0.001), depth (P < 0.01) and diameter (P < 0.001) of sella turcica with race. The diameter of sella turcica was the only parameter significantly associated with race, gender and age. Significant differences were found between cephalometric norms in different racial groups. These findings assist orthodontists, neurosurgeons, and forensic medical investigatiors during orthodontic treatment planning, diagnosis of pathology of the pituitary gland, and age determination.

Effects of different surface treatments on the shear bond strength of veneering ceramic materials to zirconia.

PURPOSE: To evaluate and compare the effect of different materials and techniques on the shear bond strength of veneering ceramic materials to zirconia. MATERIALS AND METHODS: 136 sintered zirconia cubes were prepared and randomly divided into four study groups according to corresponding methods of surface treatment and materials: GLN (grinding followed by laser scanning using Noritake Cerabien ZR), SLN (sandblasting followed by laser scanning using Noritake Cerabien ZR), GLV (grinding followed by laser scanning using VITA VM 9), and SLV (sandblasting followed by laser scanning using VITA VM 9). Spraying technique was performed to coat the core. Profilometer, SEM, XRD, EDS, universal testing machine, and stereomicroscope were used to record surface roughness Ra, surface morphology, phase transformation, elemental compositions, shear bond strength SBS values, and failure types, respectively. Specimens were investigated in unaged (not immersed in artificial saliva) and aged (stored in artificial saliva for a month) conditions to evaluate SBS values. RESULTS: Grinding and GLN as first and second surface treatments provided satisfactory Ra values in both conditions (1.05 ± 0.24 µm, 1.30 ± 0.21 µm) compared to sandblasting and other groups (P<.05). The group GLN showed the highest SBS values in both conditions (30.97 ± 3.12 MPa, 29.09 ± 4.17 MPa), while group SLV recorded the lowest (23.96 ± 3.60 MPa, 22.95 ± 3.68 Mpa) (P<.05). Sandblasting showed phase transformation from t-m. Mixed failure type was the commonest among all groups. CONCLUSION: GLN showed to be a reliable method which provided satisfactory bond strength between the veneer ceramic and zirconia. This method might preserve the integrity of fixed dental crowns.

Morphology, incidence of bridging, and dimensions of sella turcica in different racial groups.

OBJECTIVES: This study was performed to assess the morphological appearance, incidence of bridging, and linear dimensions of the sella turcica (ST) in Bosnian and Iraqi subjects, and to identify associations of sex, age, and racial group with the size of the ST. METHODS: The digital standardised lateral cephalograms of 360 Bosnian and Iraqi patients (116 female, 64 male; age range 8-28 years) were retrospectively analysed. The following ST-related parameters were analysed on the lateral cephalograms: sella morphology, sella bridging, and sella size. The data were correlated with sex, age, and race. RESULTS: The ST exhibited a normal morphology in most subjects of both races (86.7%). The frequency of partial bridging was found in 38.9 and 37.2% of Bosnian and Iraqi subjects, respectively. A significant correlation was detected between the length of the ST and sex in both the Bosnian and Iraqi subjects (p < 0.05). A direct correlation was present between patient age and the size of the ST in both races at the 0.01 and 0.001 levels for depth, length, and diameter. When race was compared with sella size, a significant difference was found in the length and depth of the ST (p <  0.001). CONCLUSIONS: Similarities were found between Bosnian and Iraqi subjects in the morphology, incidence of bridging, and linear dimensions of the ST. Length was the only parameter significantly associated with sex, age, and racial group. These findings could be used as reference standards for studying the ST in both races.

Effect of orthodontic force on the expression of PI3K, Akt, and P70S6 K in the human periodontal ligament during orthodontic loading.

The mammalian target of rapamycin (mTOR) is an atypical serine/threonine protein kinases involved in the regulation of cell growth, proliferation, and differentiation through the PI3K/Akt/mTOR/P70S6 K signalling pathway. P70S6 K as a downstream molecule of mTOR is activated by phosphorylation and subsequently promotes the synthesis of ribosomal and translational proteins. In this study, we investigated the role of PI3K, Akt, and P70S6 K in human periodontal tissue remodelling during orthodontic loading. The prepared tissue specimens taken from 4 extracted premolars were processed for immunolabelling. The changes in the expression of PI3K, Akt, and P70S6 K in the periodontal tissues were detected by real-time quantitative-polymerase chain reaction and Western blot analysis. The results from real-time quantitative-polymerase chain reaction and Western blot both showed that the expression of PI3K, Akt, and P70S6 K in the experimental group began to increase at 3 days and increased significantly at 10 days, then decreased approaching the control group level at 28 days. Our findings showed that the expression of PI3K, Akt, and P70S6 K in human periodontal ligament demonstrated a variability during the orthodontic loading, which suggested that the PI3K/Akt/mTOR/P70S6 K signal pathway was involved in orthodontic tooth movement and played a role in the process of periodontium remodelling.