The Role of Surface Chemistry in the Osseointegration of PEEK Implants.

Poly(etheretherketone) (PEEK) implants suffer from poor osseointegration because of chronic inflammation. In this study, we hypothesized that adding NH2 and COOH groups to the surface of PEEK could modulate macrophage responses by altering protein adsorption and improve its osseointegration. NH2 and COOH-functionalized PEEK surfaces induced pro- and anti-inflammatory macrophage responses, respectively, and differences in protein adsorption patterns on these surfaces were related to the varied inflammatory responses. The macrophage responses to NH2 surfaces significantly reduced the osteogenic differentiation of mesenchymal stem cells (MSCs). MSCs cultured on NH2 surfaces differentiated less than those on COOH surfaces even though NH2 surfaces promoted the most mineralization in simulated body fluid solutions. After 14 days in rat tibia unicortical defects, the bone around NH2 surfaces had thinner trabeculae and higher specific bone surface than the bone around unmodified implants; surprisingly, the NH2 implants significantly increased bone-binding over the unmodified implants, while COOH implants only showed a trend for increasing bone-binding. Taken together, these results suggest that both mineral-binding and immune responses play a role in osseointegration, and PEEK implant integration may be improved with mixtures of these two functional groups to harness the ability to reduce inflammation and bind bone strongly.

Efficacy of Aerosol Reduction Measures for Dental Aerosol Generating Procedures.

Aerosol particles generated by dental procedures could facilitate the transmission of infectious diseases and contain carcinogen particles. Such particles can penetrate common surgical masks and reach the lungs, leading to increased risk for dental care professionals. However, the risk of inhaling contaminated aerosol and the effectiveness of aerosol reduction measures in dental offices remain unclear. The present study aimed to quantify aerosols produced by drilling and scaling procedures and to evaluate present recommendations for aerosol reduction. The concentration of aerosol particles released from the mock scaling and drilling procedures on dental mannequin were measured using a TSI Optical Particle Sizer (OPS 3330) during 15-min sessions carried out in a single-patient examination room. Using a drilling procedure as the aerosol source, the aerosol reduction performance of two types of high-volume evacuators (HVEs) and a commercial off-the-shelf air purifier was evaluated in a simulated clinical setting. Using either HVEs or the air purifier individually reduced the aerosol accumulated over the course of a 15-minutes drilling procedure at a reduction rate of 94.8 to 97.6%. Using both measures simultaneously raised the reduction rate to 99.6%. The results show that existing HVEs can effectively reduce aerosol concentration generated by a drilling procedure and can be further improved by using an air purifier. Following current regulatory guidelines can ensure a low risk of inhaling contaminated aerosol for dentists, assistants, and patients.

Liquid-infused microstructured bioadhesives halt non-compressible hemorrhage.

Non-compressible hemorrhage is an unmet clinical challenge that accounts for high mortality in trauma. Rapid pressurized blood flows under hemorrhage impair the function and integrity of hemostatic agents and the adhesion of bioadhesive sealants. Here, we report the design and performance of bioinspired microstructured bioadhesives, formed with a macroporous tough xerogel infused with functional liquids. The xerogel can rapidly absorb interfacial fluids such as whole blood and promote blood clotting, while the infused liquids facilitate interfacial bonding, sealing, and antibacterial function. Their synergy enables the bioadhesives to form tough adhesion on ex vivo human and porcine tissues and diverse engineered surfaces without the need for compression, as well as on-demand instant removal and storage stability. We demonstrate a significantly improved hemostatic efficacy and biocompatibility in rats and pigs compared to non-structured counterparts and commercial products. This work opens new avenues for the development of bioadhesives and hemostatic sealants.

NSAID chronotherapy after impacted third molar extraction: a randomized controlled trial.

OBJECTIVES: Postoperative pain management impacts patients' quality of life and morbidity. Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen are widely used for this following a 3-doses-per-day regime. However, pain and inflammation follow a circadian rhythm, and animal models assessing the scheduling of NSAID administration (e.g., chronotherapy) have shown that while their use during the active phase of the day enhances postoperative recovery, their administration during the resting phase could have detrimental effects. This observation has led us to hypothesize that night administration of NSAID might be unnecessary in post-surgical scenarios. Therefore, a randomized clinical trial was conducted to test this hypothesis in surgical third molar extractions. MATERIALS AND METHODS: Seventy (18-35 years) healthy participants requiring surgical removal of impacted lower third molars were recruited and randomized into a double-blind placebo-controlled study. For three days postoperatively, the treatment group (n = 33) received ibuprofen (400 mg) at 8 AM, 1 PM, and a placebo at 8 PM, while the control group (n = 37) received ibuprofen (400 mg) at 8 AM, 1 PM, and 8 PM. Pain severity was assessed by visual analog scale (VAS) and healing indicators including facial swelling, mouth opening, and C-reactive protein blood levels were also measured. RESULTS: Pain VAS measures showed a circadian variation peaking at night. Also, no significant differences were observed between the two groups of the study in terms of postoperative pain scores (estimate: 0.50, 95% CI = [- 0.38, 1.39]) or any other healing indicator. CONCLUSIONS: Postoperative pain follows a circadian rhythm. Moreover, night administration of ibuprofen might not provide any significant benefits in terms of pain management and control of inflammation, and two doses during the day only could be sufficient for pain management after surgical interventions. KNOWLEDGE TRANSFER STATEMENT: Even though this study cannot rule out the possibility that a reduced regime is different than a standard regime, nocturnal doses of ibuprofen seem to have no clinical significance in the short term, and the results of this study provide evidence in favor of reducing ibuprofen administration from three doses to two doses only after third molar surgery.

Needle-free injection: Dental infiltration anesthesia.

This study aimed to develop an optimal Needle-Free Liquid Jet Injection (NFLJI) technique for dental infiltration anesthesia and evaluate its clinical safety and feasibility. The fluid dynamics of NFLJI in the dentoalveolar region were investigated using soft tissue phantoms supported by rigid glass. NFLJIs were performed at different incident angles and recorded using a high-speed camera. Accordingly, an optimal NFLJI for infiltration anesthesia was developed and validated on cadavers, then assessed in two pilot Randomized Controlled Trials (RCT): one for validating the safety of optimal NFLJI technique, the other for evaluating its feasibility and safety. High-speed videos showed that perpendicular NFLJIs induced significantly more regurgitation than oblique NFLJIs, which was confirmed in cadavers. Clinical trials revealed that perpendicular NFLJIs induced a high risk of bleeding (83.3%) and laceration (83.3%), whereas oblique NFLJIs induced a low risk of bleeding (33.3%) and laceration (16.7%). Moreover, the preliminary success rates of oblique NFLJIs and needle injections were both 83.3%. The recruitment took 3-5 weeks with a rate of 100%. Oblique NFLJIs could be a promising approach for dental infiltration anesthesia, causing minimal drug regurgitation with a relatively low risk of complication. The pilot RCTs confirmed the feasibility for conducting a non-inferiority RCT.

Postoperative Administration of the Acetylcholinesterase Inhibitor, Donepezil, Interferes with Bone Healing and Implant Osseointegration in a Rat Model.

Donepezil is an acetylcholinesterase inhibitor commonly used to treat mild to moderate Alzheimer's disease. Its use has been associated with increased bone mass in humans and animals. However, the effect of postoperative administration of donepezil on bone healing remains unknown. Therefore, this study aimed to assess the impact of postoperative injection of donepezil on bone healing, titanium-implant osseointegration, and soft tissue healing. Twenty-two Sprague-Dawley rats were randomly assigned to receive a daily dose of either donepezil (0.6 mg/kg) or saline as a control. In each rat, a uni-cortical defect was created in the right tibia metaphysis and a custom-made titanium implant was placed in the left tibiae. After two weeks, rats were euthanized, and their bones were analysed by Micro-CT and histology. The healing of bone defect and implant osseointegration in the rats treated with donepezil were significantly reduced compared to the saline-treated rats. Histomorphometric analysis showed lower immune cell infiltration in bone defects treated with donepezil compared to the saline-treated defects. On the other hand, the healing time of soft tissue wounds was significantly shorter in donepezil-treated rats compared to the controls. In conclusion, short-term administration of donepezil hinders bone healing whereas enhancing soft tissue healing.