A retrospective study of 12,538 internal conical connection implants focused on the long-term integrity of implant-abutment complexes.

OBJECTIVE: To evaluate the long-term integrity of implant-abutment complexes in implant systems with two internal conical angles. MATERIAL AND METHODS: 12,538 bone-level implants of two systems placed between January 2012 and December 2018 were retrospectively analyzed. Cumulative abutment/implant fracture rates in systems with larger (LA, 7.5°) and smaller (SA, 5.7°) internal conical angles were estimated using the Kaplan-Meier analysis and compared between groups. The association between implant systems and jammed abutment retrievability was evaluated by multivariable generalized estimating equation logistic regression modeling. RESULTS: For LA, the 8-year cumulative incident rate was 0.10% (95% confidence interval (CI): 0-0.24%) for implant fracture and 0.26% (95% CI: 0.11%-0.41%) for abutment fracture, demonstrating a significant difference in gender (p = .03), implant diameter (p = .01), jaw (p = .006), and antagonist tooth (p < .001). For SA, the 8-year cumulative incident rate was 0.38% (95% CI: 0-0.79%) for implant fracture and 2.62% (95% CI: 0.05%-5.13%) for abutment fracture, which was influenced by implant diameter (p < .001) and site (p = .03). The cumulative implant/abutment fracture rate was lower for LA implants, particularly for LA implant-supported single crowns (SCs) (p < .05). The abutment-retrieval success rate was 92.9% for LA and 57.1% for SA (p = .055). CONCLUSION: LA implants exhibited a lower incidence of fracture in abutment-implant complexes and a relatively higher retrievability success rate for jammed abutments.

Children's Dental Fear: Occurrence Mechanism and Prevention Guidance.

Children's dental fear (CDF) has become one of the main reasons affecting the quality of dental treatment. In order to reduce the incidence of CDF in China before and after children's dental visits, this review applies literature analysis and empirical summary methods to analyze and summarize academic discussions on this topic, including occurrence mechanism, prevention guidance, and the conclusion that the occurrence and prevention of CDF is closely related with children's internal characteristics and external influences. In the end, we propose a breakthrough of combining the CFSS-DS scale and three-grade prevention theory together in the future to provide new ideas and hypotheses for the prevention of CDF.

Comparative Evaluation of Endo-sinus Bone Augmentation After Osteotome Sinus Floor Elevation Without Grafting Using Two Radiographic Methods.

PURPOSE: Using panoramic radiograph and CBCT to compare the measurement errors of the residual bone height in the same site before implant placement in the posterior maxilla and endo-sinus bone gain after osteotome sinus floor elevation without grafting, and to evaluate endo-sinus bone augmentation before stage-two surgery with CBCT. Also, some related factors of new bone formation in the sinus were analyzed, such as small bone block elevated by osteotome at the implant apex intraoperatively. MATERIALS AND METHODS: Patients were enrolled in the retrospective study; dental implants were placed in the maxillary posterior region using osteotome sinus floor elevation without grafting. The panoramic radiograph and CBCT were taken preoperatively, immediate postoperatively, and before the stage-two surgery. Endo-sinus bone augmentation was evaluated. A generalized linear model was made to explore the related factors of endo-sinus bone gain. Also, some clinical indexes, such as sinus membrane perforation rate, implant success, and failure criteria were assessed. RESULTS: One hundred two dental implants were inserted in 91 patients. Preoperatively, the mean residual bone height was 8.53 ± 1.76 mm and 7.87 ± 1.45 mm measured using a panoramic radiograph and CBCT, respectively, with significant statistical differences (P < .05). Endo-sinus bone gains of 1.31 °æ 1.05 mm by panoramic radiograph and 1.80 ± 1.72 mm by CBCT were observed, with statistically significant differences (P < .05). The final endosinus bone gain was positively correlated with the implant protrusion length at baseline without any other relevant factors, such as elevated small bone block. CONCLUSION: Measurement errors could be relatively minimized when using CBCT. Using the osteotome sinus floor elevation technique without grafting, approximately 2 mm of endo-sinus bone could be acquired. The final endo-sinus bone gain was positively correlated with implant protrusion length at baseline. Small bone block elevated intraoperatively did not gain more endo-sinus bone.

Zinc- and strontium- co-incorporated nanorods on titanium surfaces with favorable material property, osteogenesis, and enhanced antibacterial activity.

Early infection and peri-implantitis after implant restoration are major reasons for dental implant failure. Implant-associated infections are majorly attributed to biofilm formation. In this study, co-incorporated zinc- (Zn-) and strontium- (Sr-) nanorod coating on sandblasted and acid-etched (SLA) titanium (SLA-Zn/Sr) was fabricated by hydrothermal synthesis. It was aimed at promoting osteogenesis while inhibiting biofilm formation. The nanorod-like particles (φ 30-50 nm) were found to be evenly formed on SLA-Zn/Sr (Zn: 1.49 ± 0.16 wt%; Sr: 21.69 ± 2.74 wt%) that was composed of well-crystallized ZnTiO3 and SrTiO3 phases. With a sufficient interface bonding strength (42.00 ± 3.00 MPa), SLA-Zn/Sr enhanced the corrosion resistance property of titanium. Besides, SLA-Zn/Sr promoted the cellular initial adhesion, proliferation and osteogenic differentiation of rBMSCs in vitro while inhibiting the adhesion of Staphylococcus aureus and Porphyromonas gingivalis . In addition, through down-regulating icaA gene expression, this novel surface reduced the secretion of polysaccharide intercellular adhesion (reduced by 87.9% compared to SLActive) to suppress the S. aureus biofilm formation. We, therefore, propose a new chemical modification on titanium for multifunctional implant material development. Due to the Zn/Sr co-doping in coating, material properties, early osteogenic effect and antibacterial ability of titanium can be simultaneously enhanced, which has the potential to be applied in dental implantation in the future.

A robust and tunable mitotic oscillator in artificial cells.

Single-cell analysis is pivotal to deciphering complex phenomena like heterogeneity, bistability, and asynchronous oscillations, where a population ensemble cannot represent individual behaviors. Bulk cell-free systems, despite having unique advantages of manipulation and characterization of biochemical networks, lack the essential single-cell information to understand a class of out-of-steady-state dynamics including cell cycles. Here, by encapsulating Xenopus egg extracts in water-in-oil microemulsions, we developed artificial cells that are adjustable in sizes and periods, sustain mitotic oscillations for over 30 cycles, and function in forms from the simplest cytoplasmic-only to the more complicated ones involving nuclear dynamics, mimicking real cells. Such innate flexibility and robustness make it key to studying clock properties like tunability and stochasticity. Our results also highlight energy as an important regulator of cell cycles. We demonstrate a simple, powerful, and likely generalizable strategy of integrating strengths of single-cell approaches into conventional in vitro systems to study complex clock functions.