Corrigendum to "The effect of low intensity pulsed ultrasound on mandibular condylar growth in young adult rats" [Bone Rep. 15 (2021) 101122 (December)].

[This corrects the article DOI: 10.1016/j.bonr.2021.101122.].

Datasets describing the morphometric evaluation of the adult rat mandible following growth stimulation of the condyle using ultrasound.

Evaluating morphological changes of the mandible due to the unique role of the condyle in mandibular special growth and remodeling pattern is challenging. This data describes a comprehensive evaluation using new techniques to detect morphological changes of the young adult rat mandibles treated by low intensity pulsed ultrasound (LIPUS) comparing to matching controls. Two-dimensional (2D) analysis was performed on digital photographs of the hemi-mandibles using AutoCAD software with high accuracy. The anatomical points which were more determinative and prone to visual illusion were defined with particularity. Selective combination of measurements was done to allow for a thorough morphometric evaluation of the mandible focusing on the condyle and the main direction of condylar and mandibular growth. The procedure was simulated for three-dimensional analysis of virtual models of the hemi-mandibles via Geomagic-Qualify software. In the whole procedures, conditions were strictly standardized to ensure reliability and repeatability. Further Insights, Interpretations and discussions of the present datasets can be find in https://doi.org/10.1016/j.bonr.2021.101122[1].

Mandibular condyle tissue reaction to low intensity pulsed ultrasound in young adult rats: Micro computed tomographic and histomorphometric datasets.

Mandibular condyle (MC) in postnatal life, grows mainly by endochondral bone growth which is a multistep process and the condylar cartilage plays a vital role in its regional adaptive growth. Hence, for determining the exact effect of a treatment such as low Intensity pulsed ultrasound (LIPUS) on the MC growth in animal models, it is important to reliably and reproducibly detect changes at different tissue levels and correct regions of the condyle. To this aim, micro computed tomography (µCT), as well as Alcian Blue-Pas staining, in vivo flourochrome labeling via calcein green, and Goldner's Trichrome staining on proper decalcified and undecalcified sections was performed for the harvested samples from young adult rats. Standardized procedures were used to determine volumes or regions of interest for microstructural evaluations in the middle and posterior areas of the MC. In the condylar cartilage, the thickness of fibrous, proliferative, chondroblastic, and total fibrocartilage layers; also the cell population in proliferative and chondroblastic layers were precisely measured. On the other side, using accurate methods percentage of calcifying cartilage and newly formed bone areas/bone area, bone volume fraction and specific surface, trabecular number, thickness, and separation, degree of anisotropy, bone mineral density; furthermore, the amount of actual endochondral bone growth and the osteoid thickness were quantified in subchondral cancellous bone subjacent to condylar cartilage. Data provided herein present the robust µCT and histomorphometric evaluations of the control and LIPUS treated adult MCs at cartilage and bone level. Data also highlights the difference in tissue response to the stimuli between the middle and posterior regions of the condyle. Further interpretation of these datasets can be found in https://doi.org/10.1016/j.bonr.2021.101122[1].

The effect of low intensity pulsed ultrasound on mandibular condylar growth in young adult rats.

There is a need for more effective methods to enhance mandibular growth in young adults with mandibular deficiency. Previous studies suggest that low intensity pulsed ultrasound (LIPUS) can enhance mandibular growth in growing individuals. This study aimed to evaluate the potential growth changes of the mandible following 4-week LIPUS application in young adult rats. Nineteen ≈120-day-old female rats were allocated to experimental (n = 10) and control (n = 9) groups. The animals in the experimental group were treated with LIPUS to their temporomandibular joints (TMJs) bilaterally, 20 min each day for 28 consecutive days. Animals were then euthanized; gross morphological evaluation was performed on 2D photographs and 3D virtual models of hemi-mandibles, and microstructural assessment was done for the mandibular condyle (MC). Evaluation of mineralization and microarchitecture properties of subchondral cancellous bone was performed by micro-computed tomography (µCT) scanning. Qualitative and histomorphometric analysis was done on condylar cartilage and subchondral bone following Alcian Blue/PAS and Goldner's Trichrome staining. Vital flourochrome (calcein green) labeling was also utilized to determine the amount of endochondral bone growth. Gross morphological evaluations showed a slight statistically non-significant increase especially in the main condylar growth direction in the LIPUS group. Moreover, 3D evaluation depicted an enhanced periosteal bone apposition at the site of LIPUS application. Microstructural analysis revealed that LIPUS stimulates both chondrogenesis and osteogenesis and enhances endochondral bone formation in young adult rat MC. Furthermore, the effect of LIPUS on osteogenic cells of subchondral cancellous bone was notable. To conclude, LIPUS can enhance young adult rats' MC residual growth potential.

Characterization of stem cells from the pulp of unerupted third molar tooth.

CONTEXT: Dental pulp stem cells (DPSCs) are the most diagnosed type of stem cells isolated from dental tissues. Previous studies demonstrate that tissues in earlier stages of development could be better stem cell resources for tissue engineering. AIMS: In this study, aiming at finding younger stem cell resources, we chose the pulp of human unerupted third molar teeth when the crown was completely formed and the roots had not begun their development, Nolla's 6 th developmental stage (N6 th ). MATERIALS AND METHODS: Surgical removal of the third molar was performed by aseptic technique with minimal trauma. The tissues were digested enzymatically and the resulted single cells were cultured. Immunophenotypic characterization of the cells was done via immunocytochemistry, immunofluorescence, and flow cytometry assays. Adipogenic and osteogenic differentiation potential of these cells was examined and confirmed by histochemical staining and reverse transcription-polymerase chain reaction analysis. STATISTICAL ANALYSIS USED: This study is descriptive. RESULTS: N6 th -unerupted dental pulp cultured cells expressed DPSC markers: Vimentin, CD73, CD90, CD105, CD166, CD44, CD146, and STRO-1, but did not express hematopoietic cell markers: CD14, CD34, CD45, HLA-DR and were also negative for dentin sialoprotein negative showing an undifferentiated preodontogenic state. Adipocytes differentiated from N6 th -DPSCs were positively stained with Oil-Red-O and expressed both early and late adipocyte specific genes. Formation of Alizarin-red positive condensed calcium-phosphate nodules accompanied by strong expression of two osteogenic mRNAs, exhibited osteogenic differentiation. CONCLUSION: Based on the results of this study, we suggest that N6 th -DMSCs are a viable choice for cryo-banking and future usage in regenerative therapies; however, more investigations are necessary before clinical application can commence.