Masato Matsuo

Implications of cultured periodontal ligament cells for the clinical and experimental setting: A review

The periodontal ligament (PDL) is a key contributor to the process of regeneration of the periodontium. The heterogeneous nature of the PDL tissue, its development during early adulthood, and the different conditions to which the PDL tissue is exposed to in vivo impart on the PDL unique characteristics that may be of consequence during its cultivation in vitro. Several factors affecting the in vivo setting influence the behaviour of PDL fibroblasts in culture. The purpose of this review is to address distinct factors that influence the behaviour of PDL fibroblasts in culture -in vivo-in vitro transitions, cell identification/isolation markers, primary PDL cultures and cell lines, tooth-specific factors, and donor-specific factors. Based on the reviewed studies, the authors recommendations include the use of several identification markers to confirm cell identity, use of primary cultures at early passage to maintain unique PDL heterogeneic characteristics, and noting donor conditions such as age, systemic health status, and tooth health status. Continued efforts will expand our understanding of the in vitro and in vivo behaviour of cells, with the goal of orchestrating optimal periodontal regeneration. This understanding will lead to improved evidence-based rationales for more individualized and predictable periodontal regenerative therapies.

Contribution of nitrergic nerve in canine gingival reactive hyperemia

Reactive hyperemia reflects a compensatory vasodilation response of the local vasculature in ischemic tissue. The purpose of this study is to clarify the mechanism of regulation of this response in gingival circulation by using pharmacological analysis of reactive hyperemia and histochemical analysis of gingival tissue. Application of pressure to the gingiva was used to create temporary ischemia, and gingival blood flow was measured after pressure release. Reactive hyperemia increased in proportion to the duration of pressure. Systemic hemodynamics remained unaffected by the stimulus; therefore, the gingival reactive hyperemia reflected a local adjustment in circulation. Gingival reactive hyperemia was significantly suppressed by nitric oxide (NO) synthase inhibitors, especially the neural NO synthase-selective antagonist 7-nitroindazole, but not by anticholinergic drugs, β-blockers, or antihistaminergic drugs. Moreover, immunohistochemical staining for neural NO synthase and histochemical staining for NADPH diaphorase activity were both positive in the gingival perivascular region. These histochemical and pharmacological analyses show that reactive hyperemia following pressure release is mediated by NO-induced vasodilation. Furthermore, histochemical analysis strongly suggests that NO originates from nitrergic nerves. Therefore, NO may play an important role in the neural regulation of local circulation in gingival tissue ischemia.

Effect of Ultraviolet Irradiation of the Implant Surface on Progression of Periimplantitis--A Pilot Study in Dogs.

Objective:The objective of this study was to investigate morphologically the progression of periimplantitis around an ultraviolet (UV)-light-irradiated implant in dogs. Materials and Methods:Pure titanium implants (3.3 mm in diameter and 8 mm long) were placed into dog jawbone bilaterally. Implants on one side were irradiated with UV light for 15 minutes using a photodevice immediately before placement (UV group), whereas those on the other side were not irradiated (non-UV group). Osseointegration was confirmed 90 days after implant placement by radiography. Experimental periimplantitis was induced by the application of dental floss over 90 days. Clinical and radiographic examination and micro–computed tomography (micro-CT) were performed after 90 and 180 days, and bone resorption was measured. The bone–implant interface in tissue sections was examined by light microscopy. Results:Bone resorption around the UV-irradiated implant was less pronounced than around the non–UV-irradiated implant in the ligature-induced periimplantitis model. Tissue section images revealed no contact and partial destruction at the bone–implant interface. Conclusion:Within the limitations of this preliminary investigation, it is suggested that UV-light-irradiated implants suppress spontaneous progression of periimplantitis.

The retroesophageal right subclavian artery – A case report and review –

In a student course of gross anatomy dissection at Kanagawa Dental University in 2011, we encountered anomalous case of the right subclavian artery arising from the aortic arch as the last branch in an 84-year-old Japanese male cadaver. The anomalous artery ran obliquely upward, passed behind the esophagus and trachea, and ultimately ran toward right scalene gap. The area of distribution of the anomalous artery was normal. We report a case of retroesophageal right subclavian artery, and discuss its development, or relation with the thoracic duct, and its clinical importance. Despite this type of variation being relatively rare, reports on such a case have been accumulating. Owing to the recent development of CT and MRI, the number of clinical reports on this anomaly has been increasing.

Anatomical study of the coexistence of the postaortic left brachiocephalic vein with the postaortic left renal vein with a review of the literature

In a student course of gross anatomy dissection at Kanagawa Dental University in 2009, we found an extremely rare case of the coexistence of the postaortic left brachiocephalic vein with the postaortic left renal vein of a 73-year-old Japanese male cadaver. The left brachiocephalic vein passes behind the ascending aorta and connects with the right brachiocephalic vein, and the left renal vein passes behind the abdominal aorta. These two anomalous cases mentioned above have been reported respectively. There have been few reports discussing coexistence of the postaortic left brachiocephalic vein with the postaortic left renal vein. We discuss the anatomical and embryological aspect of this anomaly with reference in the literature.