Palatal fusion is a critical step during palatogenesis. In this fusing interface, the epithelial sheets need to be removed in order to achieve mesenchymal continuity. Epithelial cellular migration is one of the possible mechanisms, and live imaging of the labeled epithelium could provide direct evidence for it. However, the removal of medial edge epithelium (MEE) between the bilateral processes takes place in the middle of the dorso-ventral axis of the palatal shelf, and thus it is challenging to capture the cellular behavior directly. Here, we evaluate cellular behavior of MEE cells using a live imaging technique with a mouse model which expresses GFP under the promoter of Keratin14 (K14-GFP) and unpaired palatal shelf culture. Using this approach, we successfully obtained live images of epithelial behavior and detected epithelial cell migration on the surface of the secondary palatal shelf without touching of the opposing shelf. Additionally, the pattern of epithelial elimination resulted in oval-shaped exposed mesenchyme, which recapitulated the situation during secondary palate fusion in vivo . Detailed image processing revealed that most of the MEE migrated in an outward direction at the boundary regions as the oval shape of the exposed mesenchyme expanded. The migration was preceded by the bulging of MEE, and disappearance of GFP signals was not evident in bulging or migrating MEE at the boundary regions. Furthermore, the MEE migration and the subsequent mesenchymal exposure were disturbed by application of ROCK inhibitor. Together, these findings indicated that epithelial cell migration contributed importantly to the MEE removal and the subsequent exposure of the underlying mesenchyme. Furthermore, they indicated that the migration of epithelial cells was regulated in a time- and space-specific manner, since unpaired palatal shelf culture exhibited these cellular behaviors even in the absence of the opposing shelf. Altogether, present data indicated that this new experimental system combining live imaging with GFP-labeled epithelium mice and unpaired palatal shelf culture enabled direct visualization of cellular migration of MEE in vitro and could be a powerful tool to investigate its cellular and molecular mechanisms.

Occlusal sounds, contact timings and time moments were measured and analysed on 10 subjects onto whom an occlusal interference was created experimentally. A full-cast double crown was unilaterally set on the upper first molar of each subject, then gradually elevated for 0.06, 0.10, 0.20 and 0.30 mm by inserting a pre-calibrated metal folio. Occlusal sound was measured with an analyser designed for the purpose. Timings and time moments were analysed with a T-scan system. All measurements were performed at least 10 times per subject. The results showed that prolonged occlusal sound duration, changes in acoustic signal waveform and increased shift of the centre of effort were observed concomitantly with crown elevation. Differences in these values at 0.06 mm as compared with those at baseline were not statistically significant. This could be explained through a physiological compensation by the periodontal ligament. The differences with baseline were statistically significant from 0.10 mm ongoing. The distribution of occlusal conacts was determined by the use of a newly developed parameter. Referred to as 'Tap Score', the parameter consists of converting contact timings occurring in seven ranges into least-square-based weighted scores. Analysis of the tap score disclosed evident imbalance between the crowned and the non-crowned side starting from 0.10 mm elevation, whereby a forward shift of the major contact point was observed on the non-crowned side. Our study demonstrated that evident changes in gnathosonic and T-scan parameters are likely to occur at a crown elevation within a 0.06-0.10 mm range.(ABSTRACT TRUNCATED AT 250 WORDS)

Objective: (1) To confirm the reliability of a Japanese version of the Youth Quality of Life Instrument-Facial Differences Module (YQOL-FD); (2) to assess the quality of life (QoL) related to facial difference in Japanese youths with cleft lip and/or palate (CL/P) using this instrument; and (3) to examine the QoL differences according to age, sex, and cleft type. Design: A cross-sectional study. Setting: Japanese youths with CL/P were recruited through our hospital and asked to complete the YQOL-FD. Participants: Sixty-nine Japanese youths (age, 11-18 years) with CL/P. Outcome Measures: The domain scores of stigma, negative consequences, negative self-image, positive consequences, and coping in the YQOL-FD, and the reliability of such scores were evaluated. Results: The instrument showed an acceptable internal consistency (Cronbach α = 0.74-0.92) and test–retest reliability (intraclass correlation coefficient = 0.94-0.98), except for the coping domain. The individual’s domain scores were spread out from the lowest score to the high scores among all domains, thus indicating the negative and positive impacts of living with facial differences regarding their QoL may vary among individuals with CL/P. All domain scores in the 15- to 18-year-old group were significantly higher than those in 11- to 14-year-old group; there were no significant differences according to sex or cleft type. Conclusions: The instrument showed acceptable reliability, except for the coping domain. There were individual variations in QoL concerning the facial difference among Japanese youths with CL/P as measured by the YQOL-FD, suggesting the importance of individual evaluations. Perceptions were influenced by age, but not sex or cleft type.

Objective This case report describes the orthodontic and prosthetic rehabilitation of a patient with resorption of the roots of the maxillary central incisors due to the ectopic maxillary canines. Clinical Considerations A 16‐year‐old woman presented with severe resorption of the roots of the maxillary central incisors due to the ectopic maxillary canines. The impacted canines were orthodontically tracted with a lingual arch‐supporting temporary central incisors and vertical elastics, and, undesirable root proximity was later corrected by moving the canines distally 1.5 mm apart. Gingival replacement cords were placed into the gingival sulcus of the canines, and tooth preparation was performed along with rotary gingival curettage of the interdental papilla. Convex form was provided for the mesial and labio‐distal subgingival contour of the restorations. Conclusions The creeping attachment of the interdental papilla was successfully achieved by the orthodontic arrangement of interdental distance and the prosthetic stimulus via the retraction cord, rotary curettage, and convex mesial subgingival contours. In addition, selective retraction of the labio‐distal gingiva by overcontoured restorations moved the gingival zenith position (GZP) distally. Finally, the canine crown morphology and gingival level mimicked the central incisors. Clinical Significance This clinical report introduces a treatment workflow of to recover the esthetic disturbance due to severe root resorption of the maxillary central incisors associated with impacted maxillary canines. The present orthodontic and prosthetic procedure can improve both hard and soft tissue esthetics and could be used in similar cases, such as malformed teeth and tooth autotransplantation or transposition with disturbances in the interdental papilla height or the GZP.