Dental implant placement through impacted teeth or residual roots as an alternative to invasive extraction surgeries: a systematic literature review

Aesthetical and Functional Rehabilitation for an Ankylosed Maxillary Canine-A Case Report

Background: As the functional and aesthetical importance of the canine cannot be overstated, the management of a missing canine is challenging. This case report describes the treatment of an infra-occluded ankylosed maxillary canine in a patient with previously failed orthodontic treatment. Case description: A 20-year-old patient sought a second opinion for orthodontic treatment failure. The patient presented with an impacted, ankylosed, and severely infra-occluded right maxillary canine, as well as an iatrogenic clockwise cant of the maxillary occlusal plane and several root resorptions. The treatment corrected the cant of the occlusal plane while avoiding further root resorption, partially extracted the upper right canine, improved the quality and quantity of the soft tissue in the newly edentulous area, and provided a prosthetic rehabilitation using a lithium disilicate ceramic resin-bonded cantilever bridge. Conclusions: The use of a cantilevered bridge resulted in an aesthetically pleasing and minimally invasive rehabilitation. This technique is reversible, does not affect pulp vitality, and is a viable solution for rehabilitating the smiles of young patients. Clinical significance: The smile rehabilitation for an ankylosed maxillary canine, especially in the case of a previously failed orthodontic treatment, is an important clinical challenge. A minimally invasive long-term restoration with a cantilever bridge is a viable solution. Functional and aesthetically pleasant results can be achieved with a multidisciplinary approach.

Unconventional Dental Implant Placement Through an Impacted Maxillary Central Incisor in Stable Contact With Enamel and Dentin: A Case Report

When edentulism is accompanied by an impacted tooth, conventional treatment usually involves traumatic tooth extraction, which would inevitably destroy the surrounding alveolar bone and cause unfavorable esthetics, especially for anterior teeth. Recently, implant placement through the impacted tooth or residual root has been proposed as an alternative to invasive extraction. A particular type of integration has been observed between dentin/cementum and titanium implant, while enamel-implant contact has not been reported. In this article, an implant was placed through the impacted maxillary central incisor, thereby avoiding an invasive extraction surgery. The buccal section of the tooth, including crown enamel, was retained in situ for buccal alveolar ridge preservation. The follow-up results were satisfactory, and a stable enamel-implant contact was observed. Combining with previous similar studies, this technique opens intriguing possibilities and brings fresh insight for the concept of dentointegration. More histological and clinical studies with long-term follow-up are warranted before endorsing this technique in routine application.

Computer guided root tip extraction and implant placement: A clinical report

Extraction of a residual root tip and implant placement can be challenging because of the complexity and invasiveness of the procedure. Improvised application of a guided implant surgery may avoid such challenges. This clinical report presents an innovative technique combining a 3-dimensionally printed surgical guide with conventional instrumentation for a residual root tip extraction in a minimally invasive and predictable way.

Adhesion of Neurons and Glial Cells with Nanocolumnar TiN Films for Brain-Machine Interfaces

Coupling of cells to biomaterials is a prerequisite for most biomedical applications; e.g., neuroelectrodes can only stimulate brain tissue in vivo if the electric signal is transferred to neurons attached to the electrodes' surface. Besides, cell survival in vitro also depends on the interaction of cells with the underlying substrate materials; in vitro assays such as multielectrode arrays determine cellular behavior by electrical coupling to the adherent cells. In our study, we investigated the interaction of neurons and glial cells with different electrode materials such as TiN and nanocolumnar TiN surfaces in contrast to gold and ITO substrates. Employing single-cell force spectroscopy, we quantified short-term interaction forces between neuron-like cells (SH-SY5Y cells) and glial cells (U-87 MG cells) for the different materials and contact times. Additionally, results were compared to the spreading dynamics of cells for different culture times as a function of the underlying substrate. The adhesion behavior of glial cells was almost independent of the biomaterial and the maximum growth areas were already seen after one day; however, adhesion dynamics of neurons relied on culture material and time. Neurons spread much better on TiN and nanocolumnar TiN and also formed more neurites after three days in culture. Our designed nanocolumnar TiN offers the possibility for building miniaturized microelectrode arrays for impedance spectroscopy without losing detection sensitivity due to a lowered self-impedance of the electrode. Hence, our results show that this biomaterial promotes adhesion and spreading of neurons and glial cells, which are important for many biomedical applications in vitro and in vivo.