Effect of varying auxiliaries on maxillary incisor torque control with clear aligners: A finite element analysis.

INTRODUCTION: This study aimed to evaluate the effects of varying auxiliaries on tooth movement and stress distribution when maxillary central incisors were torqued 1° with a clear aligner through finite element analysis. METHODS: Three-dimensional finite element models, including maxillary alveolar bone, periodontal ligament, dentition, and clear aligner, were constructed. According to the auxiliaries designed on the maxillary central incisor, 5 models were created: (1) without auxiliaries (control model), (2) with the power ridge, (3) with the semi-ellipsoid attachment, (4) with the horizontal rectangular attachment, and (5) with the horizontal cylinder attachment. The tooth movement and periodontal ligament stress distribution after a palatal root torque of 1° were analyzed for each of the 5 models. RESULTS: With 1° torque predicted, the maxillary central incisor without auxiliaries showed a tendency of labial tipping, mesial tipping, and intrusion. The rotation center moved occlusally in the power ridge model. The labiolingual inclination variation increased in the semi-ellipsoid attachment model but decreased in the power ridge model. The maxillary central incisor is twisted in the distal direction in the power ridge model. The maxillary central incisor of the horizontal rectangular attachment and the horizontal cylinder attachment model behaved similarly to the control model. Periodontal stresses were concentrated in the cervical and apical areas. The maximum von Mises stresses were 11.6, 12.4, 3.81, 1.14, and 11.0 kPa in the 5 models. The semi-ellipsoid attachment model exhibited a more uniform stress distribution than the other models. CONCLUSIONS: Semi-ellipsoid attachment performed better efficacy on labiolingual inclination, and power ridge performed better efficacy on root control. However, a distal twist of maxillary incisors could be generated by the power ridge.

Endoscopic Trans-Lateral Molar Approach to Infratemporal Fossa Lesions.

BACKGROUND: To study the endoscopic trans-lateral molar (ETLM) approach to infratemporal fossa (ITF) lesions and analyze the advantages and disadvantages of this method. METHODS: Four cases of ITF lesions were analyzed retrospectively. The clinical features, diagnosis and treatments, the operative process, and clinical applications of this surgical approach were discussed. RESULTS: Postoperative pathologies were 2 pleomorphic adenomas, 1 schwannoma, and 1 inflammatory lesion. All patients had self-resolving cheek swelling and pharyngalgia in the short term, but 2 patients had numbness in the long term. There was no infection or bleeding in the postoperative period, and no difficulty in chewing after disease recovery. There was no tumor recurrence during the follow-up period. CONCLUSION: The ETLM approach is convenient, minimally invasive, and allows complete excision of benign ITF lesions, posterior to the lateral pterygoid muscle and mainly below the level of the hard palate. It is a simple and direct access to the ITF, but it is a narrow access because of the limitations of bones and soft tissues. Appropriate patient selection is mandatory for successful surgery.

Seadragon genome analysis provides insights into its phenotype and sex determination locus.

The iconic phenotype of seadragons includes leaf-like appendages, a toothless tubular mouth, and male pregnancy involving incubation of fertilized eggs on an open "brood patch." We de novo-sequenced male and female genomes of the common seadragon (Phyllopteryx taeniolatus) and its closely related species, the alligator pipefish (Syngnathoides biaculeatus). Transcription profiles from an evolutionary novelty, the leaf-like appendages, show that a set of genes typically involved in fin development have been co-opted as well as an enrichment of transcripts for potential tissue repair and immune defense genes. The zebrafish mutants for scpp5, which is lost in all syngnathids, were found to lack or have deformed pharyngeal teeth, supporting the hypothesis that the loss of scpp5 has contributed to the loss of teeth in syngnathids. A putative sex-determining locus encoding a male-specific amhr2y gene shared by common seadragon and alligator pipefish was identified.

[Electroacupuncture-induced plasticity between hand and face representations in the motor cortex in healthy subjects].

OBJECTIVE: To observe the plasticity between hand and face representations of the motor cortex of healthy volunteers after electroacupuncture(EA) at Hegu(LI4), so as to provide a scientific basis for the theory of "Hegu is indicated for orofacial problems". METHODS: Using a cross-over design (self-controlled study), 10 healthy volunteers were randomly assigned to an acupuncture group and a sham acupuncture group (two-weeks wash-out period between the two groups). Subjects in the acupuncture group received EA stimulation (2 Hz, 0.5 to 1 mA, 30 min) at LI4 on their left hands. Adhesive pads sticked on the left hands of subject in the sham acupuncture group, thus, the placebo needle provided participants with a similar appearance to that in the acupuncture group but no skin penetration, and the placebo needles were connected to an EA device with a broken wire inside. Using transcranial magnetic stimulation technology, the motor evoked potentials (MEPs) of the first dorsal interosseous muscle and the orbicularis oculi muscle in hand and face representations in the contralateral motor cortex were recorded before and after EA and sham EA, and the total amplitude, effective stimulation area and center of gravity of MEPs were calculated. RESULTS: Compared with that before intervention, for acupuncture group, the total amplitude of MEPs in hand representation in the contrala-teral motor cortex was significantly increased(P<0.05),while the total amplitude of MEPs in face representation was significantly decreased (P<0.05). The effective stimulation area in hand representation was significantly increased(P<0.01), and there was no difference in face representation(P>0.05). The difference in the center of gravity of the X-axis in hand representation was statistically significant (P<0.05)，with the center of gravity moved an average of 0.6 cm to the outside, and there was no difference in face representation (P>0.05). There was no difference in the center of gravity of the Y-axis in hand and face representations(P>0.05). For sham acupuncture group, there were no differences in total amplitude of MEPs, effective stimulation area and the center of gravity in hand and face representations (P>0.05). CONCLUSION: EA at LI4 can induce plasticity between the hand and face representations of the motor cortex in healthy volunteers (exciting the hand representation of the motor cortex, while inhibiting the motor cortex representation), which provides a scientific basis for treating facial and mouth diseases by acupuncture at LI4 and the theory of selecting acupoints of the corresponding meridian distal to the disease location.

[Etiology of hand, foot and mouth disease in Guangzhou in 2008].

OBJECTIVE: To understand the etiology of hand, foot and mouth disease (HFMD) in Guangzhou area in 2008. METHOD: Totally 1023 clinical specimens were collected from pediatric patients suspected of HFMD in 2008. TaqMan real-time RT-PCR were used for detection of enterovirus 71 (EV71), Coxsackievirus A16 (CA16) and other enteroviruses. The specimens which were enterovirus positive by RT-PCR method with universal primer but EV71 and CA16 negative, were amplified and sequenced for 5'untranslated region. RESULT: Enterovirus was identified from 434 of 1023 samples and detection rate of enterovirus was 42.42%; of the 434 samples, 276 were positive for EV71 (63.6%), 126 for CA16 (29%), 4 samples for enterovirus 84, 3 for Echovirus 11, 2 for Echovirus 9, 3 for Coxsackievirus B3, 4 for Coxsackievirus A10, 3 for Coxsackievirus A6, 6 for Coxsackievirus A12 or A5, and for 7 samples typing was difficult. CONCLUSION: The major causative agents of HFMD in Guangzhou were EV71 and CA16 in 2008, and EV84, CA10, CA12, CA6, COSB3, ECHV11, ECHV9 were also the pathogens for smaller proportions of patients.