Low-power laser irradiation promotes the proliferation and osteogenic differentiation of human periodontal ligament cells via cyclic adenosine monophosphate

Retaining or improving periodontal ligament （PDL） function is crucial for restoring periodontal defects. The aim of this study was to evaluate the physiological effects of low-power laser irradiation （LPLI） on the proliferation and osteogenic differentiation of human PDL （hPDL） cells. Cultured hPDL cel Is were irradiated （660 nm） daily with doses of O, 1, 2 or 4 J .cm-2. Cell proliferation was evaluated by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide （MTT） assay, and the effect of LPLI on osteogenic differentiation was assessed by Alizarin Red S staining and alkaline phosphatase （ALP） activity. Additionally, osteogenic marker gene expression was confirmed by real-time reverse transcription-polymerase chain reaction （RT-PCR）. Our data showed that LPLI at a dose of 2 J.cm-2 significantly promoted hPDL cell proliferation at days 3 and 5. In addition, LPLI at energy doses of 2 and 4 J.cm-2 showed potential osteogenic capacity, as it stimulated ALP activity, calcium deposition, and osteogenic gene expression. We also showed that cyclic adenosine monophosphate （cAMP） is a critical regulator of the LPLI-mediated effects on hPDL cells. This study shows that LPLI can promote the proliferation and osteogenic differentiation of hPDL cells. These results suggest the potential use of LPLI in clinical applications for periodontal tissue regeneration.

Treatment of a rotator cuff tear combined with iatrogenic glenoid fracture and shoulder instability:A rare case report

BACKGROUND The brisement manipulation is an effective treatment for refractory shoulder stiffness.Rotator cuff tears can sometimes exist in combination with adhesive capsulitis.Arthroscopic capsular release combined with rotator cuff repair has achieved good outcomes in published reports.CASE SUMMARY We report the case of a patient with right shoulder pain for more than 1 year that was suspected to have adhesive capsulitis and a rotator cuff tear that was treated with brisement manipulation and arthroscopic management.An iatrogenic glenoid fracture with shoulder instability occurred during the manipulation.Arthroscopic treatment for fracture fixation,capsular release,and rotator cuff repair was performed,and the functional results are reported.CONCLUSION Arthroscopic fixation for iatrogenic glenoid fracture and repairing coexisting rotator cuff tear can provide the stability needed for early rehabilitation.