Study on the Regeneration of Waste FCC Catalyst by Boron Modification.

Regeneration has been considered as an ideal way for the post-treatment of waste FCC catalyst (ECat). In this work, the degeneration mechanism of ECat was firstly researched and attributed to the increasing of strong acid sites accessibility of ECat in contrast with fresh FCC catalyst by adsorption FTIR. Based on the proposed degeneration mechanism, ECat was successfully regenerated through suitable weakening for strong acid sites by boron modification.

CAD/CAM design and 3D printing of a personalised rapid palatal expander for maxillary transverse deficiency.

Bone -borne ra pid ma xilla ry expansion appliances can achieve skeletal expansion while avoiding the undesirable dental side effec ts caused by a conventional rapid palatal expansion appliance. Typically, t hese (bone-bo rne appliances) included prefabricated devices, which can have limitations such as inadequate palatal adaptation leading to anch orage los s. In addit ion, a s bone thickness is not accounted for, prefabricated expanders cannot ensure the primary stability of the mini-implants.

Skeletal and dentoalveolar modifications in adults with different sagittal facial patterns after personalized miniscrew-assisted rapid palatal expansion: A prospective cone-beam computed tomography study.

Introduction: This study aimed to compare the skeletal and dental modifications in adults with different sagittal facial patterns by a personalized miniscrew-assisted rapid palatal expander (pMARPE).

Methods: Forty subjects (aged 18-28 years; 15 females and 25 males) with maxillary transverse deficiency were assigned to 1 of 3 groups (Class I, II, and III relationship) on the basis of their sagittal facial patterns. Each patient was treated with an individually customized expander.

Epidemiology and associated factors of gingivitis in adolescents in Guangdong Province, Southern China: a cross-sectional study.

Background: Gingivitis is the most prevalent form of periodontal disease in children and adolescents, being strongly associated to some socioeconomic factors and oral health behaviours. This study aimed to assess the prevalence of gingivitis and its association with socio-demographic factors and oral health-related behaviours in children aged 12-15 years in Guangdong, Southern China.

Methods: A total of 7680 children were sampled using an equal-sized, stratified, multistage, random sampling method and clinically examined between December 2015 and April 2016.

The effect of mucin, fibrinogen and IgG on the corrosion behaviour of Ni-Ti alloy and stainless steel.

In this study, Ni-Ti alloy and stainless steal were exposed to artificial saliva containing fibrinogen, IgG or mucin, and the resultant corrosion behavior was studied. The purpose was to determine the mechanisms by which different types of protein contribute to corrosion. The effect of different proteins on the electrochemical resistance of Ni-Ti and SS was tested by potentiodynamic polarization, and the repair capacity of passivation film was tested by cyclic polarization measurements.

[Three-dimensional finite element analysis of maxillary incisor retraction with step-shaped vertical closing loop].

Objective: To investigate the displacement and stress distribution of upper incisors in three-dimensional (3D) space controlled by step-shaped vertical closing loop.

Methods: The maxillary teeth and alveolar bone of a volunteer with normal occlusion were scanned with 3D spiral CT. Modeling and calculation were only carried out on right upper central incisor, lateral incisor and their alveolar bone in order to simplify the procedures.

Rapid maxillary anterior teeth retraction en masse by bone compression: a canine model.

Objective: The present study sought to establish an animal model to study the feasibility and safety of rapid retraction of maxillary anterior teeth en masse aided by alveolar surgery in order to reduce orthodontic treatment time.

Method: Extraction of the maxillary canine and alveolar surgery were performed on twelve adult beagle dogs. After that, the custom-made tooth-borne distraction devices were placed on beagles' teeth.

Long-term stability of orthodontic treatment out of retention.

Objective: To investigate the correlative factors influencing the stability of orthodontic treatment out of retention.

Methods: Pre-treatment, post-treatment and 2 approximately 8 years out of retention study models of 74 cases with malocclusion were assessed by the PAR (Peer Assessment Rating) index.

Results: (1) Out of retention, the relapse rate was 13.