Effectiveness of different intrusion modes of maxillary anterior teeth with mini-implants in clear aligner treatment: a three-dimensional finite element analysis.

BACKGROUND: The intrusion of maxillary anterior teeth is often required and there are various intrusion modes with mini-implants in clear aligner treatment. The objective of this study was to evaluate the effectiveness of maxillary anterior teeth intrusion with different intrusion modes, aiming to provide references for precise and safe intrusion movements in clinical practice. METHODS: Cone-beam computed tomography and intraoral optical scanning data of a patient were collected. Finite element models of the maxilla, maxillary dentition, periodontal ligaments (PDLs), clear aligner (CA), attachments, and mini-implants were established. Different intrusion modes of the maxillary anterior teeth were simulated by changing the mini-implant site (between central incisors, between central and lateral incisor, between lateral incisor and canine), loading site (between central incisors, on central incisor, between central and lateral incisor, between lateral incisor and canine), and loading mode (labial loading and labiolingual loading). Ten conditions were generated and intrusive forces of 100 g were applied totally. Then displacement tendency of the maxillary anterior teeth and CA, and stress of the PDLs were analyzed. RESULTS: For the central incisor under condition L14 and for the canine under conditions L11, L13, L23, and L33, the intrusion amount was negative. Under other conditions, the intrusion amount was positive. The labiolingual angulation of maxillary anterior teeth exhibited positive changes under all conditions, with greater changes under linguoincisal loading. The mesiodistal angulation of canine exhibited positive changes under labial loading, while negative changes under linguoincisal loading except for condition L14. CONCLUSIONS: The intrusion amount, labiolingual and mesiodistal angulations of the maxillary anterior teeth were affected by the mini-implant site, loading site, and loading mode. Labial and linguoincisal loading may have opposite effects on the intrusion amount of maxillary anterior teeth and the mesiodistal angulation of canine. The labiolingual angulation of the maxillary incisors would increase under all intrusion modes, with greater increases under linguoincisal loading.

[Studies on sesquiterpenes from Solanum septemlobum].

By means of preparative HPTLC and column chromatography over silica gel and Sephadex LH-20, ten sesquiterpenes were isolated and purified from the whole plants of Solanum septemlobum Bunge. Based on the physico-chemical properties and spectral data, their structures were elucidated and identified as: lyratol D(1), solajiangxin B(2), 1 ,2-dehydrocyperone(3), solanerianone A (4), dehydrocarissone(5), ligucyperonol(6), nardoeudesmol A(7), solajiangxin F(8), and lyratol B(9), solajiangxin D(10). For the first time, compounds 1-10 were isolated from Solanum septemlobum, and compounds 5-7 were obtained from the genus Solanum.

New eudesmane-type sesquiterpenoid from Solanum lyratum with cytotoxic activity.

In our continuing effort to discover more new cytotoxic sesquiterpenoids from Solanum lyratum, one new eudesmane-type sesquiterpenoid (1, 3-keto-eudesm-9ß,11-diol, named lyratol G), together with one known eudesmane-type sesquiterpenoid (2, 1ß-hydroxy-1,2-dihydro-α-santonin), was obtained. The structure of the new sesquiterpenoid was elucidated on the basis of integrated spectroscopic techniques, mainly HR-FAB-MS, 1D and 2D NMR ((1)H-(1)H COSY, HMQC, HMBC and ROESY). In vitro, two sesquiterpenoids were found to exhibit significant cytotoxicity against three cancer cell lines (P-388, HONE-1 and HT-29), and gave IC50 values in the range of 3.1-6.9 µM.