Influence of mandibular distal extension implant-supported removable partial dentures on the force exerted on maxillary anterior teeth

Implant-assisted removable partial dentures: Part I. a scoping review of clinical applications

PURPOSE

This scoping review aimed to systematically map research regarding implant-assisted removable partial dentures (IARPDs), and identify existing gaps in knowledge.

STUDY SELECTION

Two reviewers independently conducted a search of the MEDLINE-PubMed and Scopus databases according to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) extension for Scoping Review and included articles published in English up to August 31, 2022, including human studies, reviews, and in vitro studies. Expert opinions, animal studies, and clinical studies involving complete overdentures were excluded, and ten aspects for establishing the treatment strategy for IARPDs were examined.

RESULTS

One hundred and twelve articles were chosen. There were two treatment modalities: IARPDs retained by implant- and tooth-supported surveyed single crowns (SCs) or fixed partial dentures (FPDs). In IARPDs retained by tooth-supported surveyed SCs or FPDs, the survival rate of dental implants for IARPDs was relatively higher with a wide range of marginal bone loss and many complications, but with improved functional performance, oral health-related quality of life, and patient satisfaction. There were limited data on survival or success rates and designs of IARPDs, attachment selections, length and diameter, inclination, placement sites, and loading protocols of implants, regardless of prosthetic types. There was limited information on maxillary IARPDs except for survival rates of implants.

CONCLUSIONS

Although IARPDs could become a useful treatment strategy, there is limited scientific consensus with gaps in knowledge about their use. Additional well-designed clinical and in vitro studies are necessary to scientifically establish IARPDs as definitive prostheses in implant dentistry.

The influence of maxillary incisor angles on the stress distributions of temporomandibular joints under incisal biting

BACKGROUND AND OBJECTIVE

The incisal biting was one of the most regular jaw activities. The direction of bite force on the incisor tip and the mandible position were relevant to the incisor angle as biting. This study was carried out to explore the influence on the temporomandibular joint (TMJ) caused by the incisor angle.

METHODS

Twenty individuals belonging to three incisor subtypes of the buccal type were recruited. In addition, the 3D models including the maxillary, mandible and discs were established based on their cone-beam computed tomography and magnetic resonance imaging scannings. Then, the mandibular ligaments and the discal attachments were simulated in the finite element models to analyze the stress distributions of the TMJs under incisal biting.

RESULTS

The TMJ stresses of subtype I showed normal range and distribution. The stresses of the intermediate temporal bone tended to increase in subtype II. The intermediate and posterior bands of the discs sustained greater tensile stresses in subtype III.

CONCLUSIONS

Abnormal stress distributions are harmful to TMJs, so the incisor cusp was not suggested to incline to the palatal side too much.

Anti-inflammatory effects of the immobilization of SEMA4D on titanium surfaces in an endothelial cell/macrophage indirect coculture model

In this study, we established a procedure to prepare a Semaphorin4D (SEMA4D)-immobilized titanium surface and explored its effects on macrophage behaviors in an endothelial cell/macrophage indirect coculture model. The SEMA4D-bovine serum albumin complex was immobilized onto a preprocessed poly L-lysine titanium surface through NaOH hydrothermal treatment and self-assembly technology. All titanium specimens were examined for surface microstructure, surface element composition, and surface wettability by field emission scanning electron microscopy, x-ray photoelectron spectroscopy (XPS), and water contact angle measurement, respectively. Subsequently, we constructed an endothelial cell/macrophage indirect coculture model and evaluated the activation of NF-κB signaling pathway and the expression of proinflammatory cytokines (TNFα, IL-6, and IL-1β) in macrophages. In XPS analysis, the SEMA4D-immobilized titanium surface appeared as a loose porous structure covered with uniform film, which exhibited better hydrophilicity than the control smooth titanium surface. In the indirect coculture model, SEMA4D attenuated the activation of NF-κB signaling pathway of lipopolysaccharide-stimulated THP-1 macrophages, thereby downregulating the expression of proinflammatory cytokines in macrophages. In conclusion, SEMA4D could be immobilized on titanium surfaces through NaOH hydrothermal treatment and self-assembly technology. Meanwhile, SEMA4D immobilization altered the characteristics of the titanium surfaces, which negatively regulated macrophage behaviors in the endothelial cell/macrophage indirect coculture model.