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The problems caused by proximal contact loss (PCL) of dental implants have been a mainstream research topic in recent years, and scholars are unanimously committed to analyzing their causes and related factors, aiming to identify solutions to the problems related to PCL. The effects of the anterior component of force (ACF), the lifelong remolding of the adult craniofacial jaw and alveolar socket, and the osseointegration characteristics of dental implants are the main causes of PCL. On the one hand, the closing movement of the mandible causes the ACF of the tooth to move through the posterior molar cusp. Moreover, drifting between the upper and lower posterior teeth and mandibular anterior teeth can cause the anterior teeth of the upper and lower jaws to be displaced labially. On the other hand, reconstruction of the jaw, alveolar socket and tooth root, the forward horizontal force of the masticatory muscles, the dynamic component of the jaw and the forward force generated by the oblique plane of the tooth cusp can cause the natural tooth to experience near-middle drift. Additionally, natural teeth can shift horizontally and vertically and rotate to accommodate remodeling of the stomatognathic system and maintain oral function. Nevertheless, the lack of a natural periodontal membrane during implant osseointegration, the lack of a physiological basis for near-medium drift, the small average degree of vertical motion and the integrated silence of dental implants without the overall drift characteristics of natural teeth increases the probability of PCL. The high incidence of PCL is clearly associated with the duration of prosthesis delivery and the mesial position; but it is also affected by the magnitude of the bite force, occlusion, the adjacent teeth, restoration design, implant location, jaw, and patient age and sex. PCL has shown a significant correlation with food impaction, but not a one-to-one correspondence, and did not meet the necessary and sufficient conditions. PCL is also associated with peri-implant lesions as well as dental caries. PCL prevention included informed consent, regular examinations, selection of retention options, point of contact enhancement, occlusal splints, and the application of multipurpose digital crowns. Management of the PCL includes adjacent contact point additions, orthodontic traction, and occlusal adjustment. Existing methods can solve the problem of food impaction in the short term with comprehensive intervention to seek stable, long-term effects. Symmetric and balanced considerations will expand the treatment of issues caused by PCL.

Following the introduction of osteo-immunomodulation as a new and important strategy to enhance material osseointegration, achieving an appropriate immune response after biomaterial implantation has become a significant challenge for efficient bone repair. In this study, a nanosilicate-reinforced sodium alginate (SA) hydrogel was fabricated by introducing montmorillonite (MMT) nanoparticles. Meanwhile, an immunogenically bioactive agent, harmine (HM), was loaded and released to induce macrophage differentiation into the M2 type. The fabricated SA/MMT/HM (SMH) hydrogel exhibited improved mechanical stiffness and stability, which also efficiently promoted macrophage anti-inflammatory M2 phenotype polarization and enhanced the secretion of pro-tissue healing cytokines for inducing a favorable immunomodulatory microenvironment for the osteogenic differentiation of bone marrow stromal cells (BMSCs). Furthermore, a rat air-pouch model and a critical-size bone defect model were used and the results showed that the SMH hydrogel increased the proportion of M2 macrophages and markedly reduced local inflammation, while enhancing desirable new bone formation. Transcriptomic analysis revealed that the SMH hydrogel accelerated the M1-to-M2 transition of macrophages by inhibiting relevant inflammatory signaling pathways and activating the PI3K-AKT1 signaling pathway. Taken together, this high-intensity immunomodulatory hydrogel may be a promising biomaterial for bone regeneration and provide a valuable base and positive enlightenment for massive bone defect repair. [ABSTRACT FROM AUTHOR]

However, due to patient discomfort in impression taking and difficulties in prosthesis fabrication, the clinical application of obturators is significantly limited. (F) The fabricated hollow obturator; (G) the weight of the obturator was 4.1 g. gl Step 4: Obturator Try-In The obturator was smoothly inserted into the patient's fistula with an accurate fit and excellent sealing (Fig. Keywords: additive manufacturing; computer-aided design; intraoral scanning; obturator; oronasal fistula; powder bed fusion EN additive manufacturing computer-aided design intraoral scanning obturator oronasal fistula powder bed fusion 1507 1512 6 05/11/23 20230601 NES 230601 This study developed a novel digital workflow to fabricate a 3D printed hollow obturator for the prosthetic reconstruction of palatal fistula. The convex part of the obturator was allowed to partly enter the oronasal fistula to seal the tissue defect, and the concave surface of the obturator was designed to reconstruct the normal anatomic contour of the hard palate. [Extracted from the article]