Denticleless E3 ubiquitin protein ligase (DTL) maintains the proliferation and differentiation of epidermis and hair follicles during skin development.

BACKGROUND: A precise balance between the proliferation and differentiation of epidermal progenitors is required to achieve the barrier function during the development of epidermis. During the entire process of skin development, the newly formed basal layer cells divide, differentiate, and migrate outward to the surface of the skin, which is tightly regulated by a series of events related to cell cycle progression. The CRL4DTL complex (Cullin 4 RING ligase, in association with the substrate receptor DTL) has long emerged as a master regulator in various cellular processes, which mediates the degradation of key cell cycle proteins. However, the roles of DTL in regulating epidermal morphogenesis during skin development remain unclear. RESULTS: We showed that DTL deficiency in epidermal progenitor cells leads to defects in epidermal stratification and loss of hair follicles accompanied by reduced epidermal progenitor cells and disturbed cell cycle progression during skin development. Transcriptome analysis revealed that p53 pathway is activated in DTL-depleted epidermal progenitor cells. The apoptosis of epidermal cells showed in DTL deficiency mice is rescued by the absence of p53, but the proliferation and differentiation defects were p53-independent. CONCLUSION: Our findings indicate that DTL plays a vital role in epidermal malformation during skin development.

Efficacy of Er:YAG laser irradiation for decontamination and its effect on biocompatibility of different titanium surfaces.

BACKGROUND: Erbium yttrium-aluminum-garnet (Er:YAG) laser have been shown to be suitable for decontamination of titanium surfaces at a wide range of energy settings, however, high intensity of laser irradiation destroy titanium surface and low intensity cannot remove enough microbial biofilm. The aim of this study was to investigate the optimal energy setting of Er:YAG laser for decontamination of sandblasted/acid-etched (SLA) and hydroxyapatite (HA) titanium surfaces. MATERIAL AND METHODS: After supragingival biofilm construction in vivo, SLA and HA titanium discs were divided into three groups: blank control (BC, clean discs), experimental control (EC, contaminated discs) and experimental groups (EP, contaminated discs irradiated by Er:YAG laser at 40, 70, and 100 mJ/pulse). Scanning electron microscopy (SEM), live/dead bacterial fluorescent detection, and colony counting assay were used to detect the efficacy of laser decontamination. To investigate the effect of laser decontamination on titanium surface biocompatibility, MC3T3-E1 cell adhesion and proliferation activity were examined by SEM and CCK-8 assay. RESULTS: Er:YAG laser irradiation at 100 mJ/pulse removed 84.1% of bacteria from SLA titanium surface; laser irradiation at 70 and 100 mJ/pulse removed 76.4% and 77.85% of bacteria from HA titanium surface respectively. Laser irradiation improved MC3T3-E1 cell adhesion on both titanium surfaces. For SLA titanium discs, 100 mJ/pulse group displayed excellent cellular proliferation activity higher than that in BC group (P < 0.01). For HA titanium discs, 70 mJ/pulse group showed the highest activity comparable to BC group (P > 0.05). CONCLUSIONS: With regards to efficient microbial biofilm decontamination and biocompatibility maintenance, Er:YAG laser at 100 mJ/pulse and 70 mJ/pulse are considered as the optimal energy settings for SLA titanium and HA titanium surface respectively. This study provides theoretical basis for the clinical application of Er:YAG laser in the treatment of peri-implantitis.

Autogenous bone ring augmentation around single tooth implantation in the esthetic zone: A retrospective case series study with 2-3 years of follow-up.

Background: /purpose: Bone ring technique (BRT) is an effective method to reconstruct alveolar bone defects with simultaneous implant placement. This study aimed to evaluate the efficacy of the BRT in single maxillary anterior tooth implantation and its esthetic outcomes over 2-3 years of follow-up. Materials and methods: Fifteen patients with single maxillary incisor loss received autogenous BRT with simultaneous implant placement. The vertical/horizontal bone gain, remaining vertical bone height (RVBH), remaining buccal bone width (RBBW), and vertical/horizontal bone resorption around implant over 2-3 years of follow-up were measured by using cone-beam computed tomography. Esthetic results including white esthetic score (WES), pink esthetic score (PES), and papilla index (PI) were evaluated by clinical recorded photographs. Results: All implants showed evidence of osseointegration, and the mean vertical and horizontal bone gain of 14 sites was 5.55 ± 0.87 mm and 4.73 ± 0.70 mm, respectively. During 2-3 years of follow-up, all mean values of RBBW were more than 2 mm. Main vertical bone loss appeared within 4 months after surgery and the RVBH value decreased as the follow-up duration continued. Maximum buccal bone thickness resorption mostly appeared in the middle level of the implant during the primary two follow-up periods (P < 0.05). Esthetic results showed that the mean WES/PES was higher than 17, and more than half cases demonstrated relatively high PI (3 points) throughout the follow-up. Conclusion: BRT could achieve excellent bone augmentation effect and can offer predictable esthetic outcomes for single tooth implant restoration in the esthetic zone.