Transition of endochondral bone formation at the normal and botulinum-treated mandibular condyle of growing juvenile rat.

Objective: The aim of this study was to understand the temporal and spatial distribution of canonical endochondral ossification (CEO) and non-canonical endochondral ossification (NCEO) of the normal growing rat condyle, and to evaluate their histomorphological changes following the simultaneous hypotrophy of the unilateral masticatory closing muscles with botulinum toxin (BTX).

Design: 46 rats at postnatal 4 weeks were used for the experiment and euthanized at postnatal 4, 8, and 16 weeks. The right masticatory muscles of rats in experimental group were injected with BTX, the left being injected with saline as a control.

Reduction malarplasty using a simulated surgical guide for asymmetric/prominent zygoma.

Background: The present study introduces a reduction malarplasty using a three-dimensional (3D)-printed surgical guide and evaluates the guide's technical applicability.

Methods: Twenty malarplasties were performed for 12 subjects with zygomatic asymmetry/prominency using the current method. 3D reconstruction of the craniomaxillofacial region and fine dental occlusion was made with image data from computed tomograpy and dental scanning.

Fully-customized distraction assembly for maxillofacial distraction osteogenesis: a novel device and its experimental accuracy verification.

Background: A new distraction osteogenesis assembly system comprising a fully customized CAD/CAM-based fixation unit and ready-made distraction unit was developed. The aim of this study was to introduce our new distraction system and to evaluate its accuracy level in a sampled mandibular distraction osteogenesis.

Methods: Our system consists of a fully customized CAD/CAM-based fixation plate unit with two plates for each moving and anchoring part, and a ready-made distraction unit with attachment slots for fixation plates.

Mandibular Vertical Growth Deficiency After Botulinum-Induced Hypotrophy of Masticatory Closing Muscles in Juvenile Nonhuman Primates.

The purpose of this study was to investigate the relationship between masticatory muscular hypotrophy and mandibular growth in juvenile nonhuman primates (cynolmolgus monkeys, Macaca fasicularis). We hypothesized that botulinum toxin (BTX)-induced neuro-muscular junctional block and its resultant hypotrophy of masticatory muscles would produce mandibular growth disturbances in size and shape. Ten male cynomolgus monkeys were divided into three groups: group I (control; = 3), group II (unilateral BTX; = 4), and group III (bilateral BTX; = 3).

Compensatory dentoalveolar supraeruption and occlusal plane cant after botulinum-induced hypotrophy of masticatory closing muscles in juvenile rats.

Objective: The purpose of this study was to investigate changes in the dentoalveolus and occlusal plane associated with the hypotrophy of unilateral masticatory muscles following botulinum toxin (BTX) treatment in the juvenile period of rats.

Design: We hypothesized that the loss of functional loading of masticatory muscles and occlusal force invites compensatory dentoalveolar supraeruption, accelerating occlusal cant and skeletal asymmetry. In order to confirm this hypothesis, six-week-old male rats (N = 5) were treated with BTX simultaneously at the unilateral masseter, temporalis, and medial pterygoid muscles, with a booster injection after six weeks for the experimental group.

Axin2 overexpression promotes the early epithelial disintegration and fusion of facial prominences during avian lip development.

The epithelial disintegration and the mesenchymal bridging are critical steps in the fusion of facial prominences during the upper lip development. These processes of epithelial-mesenchymal transition and programmed cell death are mainly influenced by Wnt signals. Axis inhibition protein2 (Axin2), a major component of the Wnt pathway, has been reported to be involved in lip development and cleft pathogenesis.

Skeletal unit construction of rat mandible based on the masticatory muscle anatomy and double microcomputed tomography.

This study aimed to divide the mandible into skeletal units based on three-dimensional (3D) muscular anatomy with microcomputed tomography (micro-CT) of Sprague-Dawley rat. Five normal rats were micro-CT scanned at 12 weeks of age before and after contrast enhancements for the masticatory muscles. Three-dimensional reconstruction of the mandible was performed from the initial micro-CT images, followed by segmentation of the masticatory muscles using the second enhanced micro-CT data.

Three-dimensional growth pattern of the rat mandible revealed by periodic live micro-computed tomography.

Objective: We wanted to evaluate the three-dimensional (3D) mandibular growth of Sprague-Dawley rats from 4th to 16th postnatal weeks with periodic and live micro-computed tomographic scanning.

Design: Twenty Sprague-Dawley rats were used for micro-CT scanning from 4th to 16th postnatal weeks. After 3D reconstruction of rat mandible, we performed the linear and angular measurements and the superimposition of the 3D models to evaluate the mandibular growth of rat.

Separate development of the maxilla and mandible is controlled by regional signaling of the maxillomandibular junction during avian development.

Background: Syngnathia is a congenital craniofacial disorder characterized by bony or soft tissue fusion of upper and lower jaws. Previous studies suggested some causative signals, such as Foxc1 or Bmp4, cause the disruption of maxillomandibular identity, but their location and the interactive signals involved remain unexplored. We wanted to examine the embryonic origin of syngnathia based on the assumption that it may be located at the separation between the maxillary and mandibular processes.

Bimolecular fluorescence complementation; lighting-up tau-tau interaction in living cells.

Abnormal tau aggregation is a pathological hallmark of many neurodegenerative disorders and it is becoming apparent that soluble tau aggregates play a key role in neurodegeneration and memory impairment. Despite this pathological importance, there is currently no single method that allows monitoring soluble tau species in living cells. In this regard, we developed a cell-based sensor that visualizes tau self-assembly.