Purpose: The purpose of this study was to understand the effects of cathepsin A on the cytodifferentiation of periodontal ligament cells.

 Methods: Expression of cathepsin A was assessed by RT-PCR and immunoblotting in mouse periodontal ligament cells (MPDL22). MPDL22 were incubated with cathepsin A inhibitor ebelactone B and calcification-related gene expression was assessed by real-time PCR. To evaluate the genetic risk factors of cathepsin A for aggressive periodontitis in a Japanese population, we utilized an exome sequencing database.

 Results: Cathepsin A was expressed in MPDL22. Ebelactone B clearly inhibited the expression of calcification-related genes osteopontin, osteonectin, and type Ⅰ collagen in MPDL22. Two single nucleotide polymorphisms (SNP) in cathepsin A, rs181943893 (c.54G＞C, p.Leu18=) and rs72555383 (c.33GCT [7], p.Leu19del), showed significantly different minor allele frequency through case-control exome sequencing.

 Conclusions: We found that the cathepsin A inhibitor ebelactone B inhibited the cytodifferentiation of periodontal ligament cells. We also found that SNP rs181943893 and rs72555383 were genetic risk factors for aggressive periodontitis in a Japanese population, indicating that cathepsin A plays an important role in maintaining the homeostasis of periodontal ligament tissues.

 Purpose: Recontouring of anterior teeth is often required as the final step of orthodontic treatment in order to optimize esthetics and functions. Orthodontic treatment may be performed on the premise that direct resin composite restorations are less invasive and show higher bond strength in comparison with indirect resin composite restorations. This case report describes direct resin composite restoration on the maxillary left and right lateral incisors and canines using the injectable composite resin technique with a digital workflow after orthodontic treatment for esthetic and functional disorders caused by missing maxillary left and right central incisors.

 Case: A 50-year-old female patient was referred to our clinic and presented with missing maxillary right and left central incisors that had been extracted. The following were observed after orthodontic treatment: (1) Approximately 2-mm spaces existed between the maxillary lateral incisors and canines on both the left and right sides, (2) Tight contact was observed between the maxillary left and right lateral incisors. (3) Esthetic and functional disorders were observed on the maxillary anterior teeth. After taking an optical impression with an intra-oral scanner, the restorations were digitally designed and transparent silicone index was fabricated from a 3-D printed cast of the digital wax-up. After the lateral incisors and canines were etched with phosphoric acid gel and a two-step self-etch system was applied, the transparent silicone index was set on the anterior tooth. Highly filled injectable resin composite was applied into the transparent silicone index and light-cured for at least 20 seconds from both the labial and palatal sides for each tooth. After removal of the transparent silicone index, excess resin composite on the gingiva was removed. Occlusal adjustment and polishing were performed.

 Results: The outcome at the 6-month follow-up was excellent.

 Conclusion: Recontouring of anterior teeth using the injectable composite resin technique with a digital workflow after orthodontic treatment for esthetic and functional disorders was successful in this case. The presented injectable composite resin technique with a digital workflow significantly simplifies and expedites the composite placement compared to the free-hand technique.