Cellularised Biomaterials Used as Gingival Connective Tissue Substitutes In Vivo: Systematic Review

Developing an in vitro model of gingival connective tissue, mimicking the original structure and composition of gingiva for clinical grafting is relevant for personalised treatment of missing gingiva. Using tissue engineering techniques allows to bypass limitations encountered with existing solutions to increase oral soft tissue volume. This review aims to systematically analyse the different currently existing cellularised materials and technologies used to engineer gingival substitutes for in vivo applications. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. An electronic search on PubMed, Scopus, Web of Science and Cochrane Library databases was conducted to identify suitable studies. In vivo studies about gingival substitute and graft containing oral cells compared with a control to investigate the graft remodelling were included. Risk of bias in the included studies was assessed using the Systematic Review Centre for Laboratory animal Experimentation (SYRCLE) 10-item checklist. Out of 631 screened studies, 19 were included. Animal models were mostly rodents, and the most used implantation was subcutaneous. According to the SYRCLE tool, low-to-unclear risk of bias were prevalent. Studies checked vascularisation and extracellular remodelling up to 60 days after implantation of the cellularized biomaterial. Cells used were mostly fibroblasts and stem cells from oral origin. Grafts presenting vascularisation potential after implantation were produced by tissue engineering technologies including cell seeding or embedding for 14, cell sheets for 2, microsphere for 1 and extrusion 3D bioprinting for 2. Components used to build the scaffold containing the cells are all naturally derived and are mainly fibrin, gelatine, collagen, agarose, alginate, fibroin, guar gum, hyaluronic acid, and decellularised extracellular matrix. The most recurring crosslinking method was using chemicals. All studies except 1 reported vascularisation of the graft after implantation and some detailed extracellular matrix remodelling. Current solutions are not efficient enough. By assessing the relevant studies on the subject, this systematic review showed that a diversity of cellularised biomaterials substituting gingival connective tissue enable vascularisation and extracellular remodelling. Taking results of this review in count could help improving current bio-inks used in 3D bioprinting for in vivo applications compensating for gingival loss.

The use of digital technologies in peri-implant soft tissue augmentation - A narrative review on planning, measurements, monitoring and aesthetics

OBJECTIVE

To identify the different uses and modalities of digital technologies to diagnose, plan and monitor peri-implant soft tissue conditions and aesthetics.

METHODS

A comprehensive narrative review of pertinent literature was conducted, critically appraising key digital technologies that may assist peri-implant soft tissue augmentation and assessment. An electronic search on four databases including studies published prior to 1st July 2023 was performed and supplemented by a manual search.

RESULTS

Predominantly, tools such as cone beam computed tomography (CBCT), intraoral scanning (iOS), intraoral ultrasonography and digital spectrophotometry were commonly to assess and monitor peri-implant soft tissues. The main clinical and research applications included: (i) initial assessment of mucosal thickness, supra-crestal tissue height and keratinized mucosa width, (ii) evaluation of peri-implant soft tissue health and inflammation, (iii) monitoring profilometric changes and midfacial mucosal margin stability over time and (iv) aesthetic evaluation through colour assessment. While evidence for some digital tools may be limited, the integration of digital technologies into peri-implant soft tissue management holds great promise. These technologies offer improved precision, comfort and speed in assessment, benefiting both patients and clinicians.

CONCLUSION

As digital technologies progress, their full potential in peri-implant soft tissue augmentation and their value will become more evident with ongoing research. Embracing these innovations and their potential benefits is recommended to ensure that during progress in implant dentistry, patient care is not hindered.

Use of Human Gingival Fibroblasts for Pre-Vascularization Strategies in Oral Tissue Engineering

BACKGROUND

Cocultures of human gingival fibrobasts (hGF) and endothelial cells could enhance regeneration and repair models as well as improve vascularization limitations in tissue engineering. The aim of this study was to assess if hGF could support formation of stable vessel-like networks.

METHODS

Explant primary hGF were isolated from gum surgical wastes collected from healthy patients with no history of periodontitis. Human umbilical vein endothelial cells (HUVEC) were two-dimensional (2D) and three-dimensional (3D) cocultured in vitro with hGF at a cell ratio of 1:1 and medium of 1:1 of their respective media during at least 31 days. Vessel quantification of HUVEC networks was performed. In order to investigate the pericyte-like properties of hGF, the expression of perivascular markers α-SMA, NG2, CD146 and PDGFR-β was studied using immunocytochemistry and flow cytometry on 2D cultures.

RESULTS

hGF were able to support a long-lasting HUVEC network at least 31 days, even in the absence of a bioreactor with flow. As observed, HUVEC started to communicate with each other from day 7, constructing a network. Their interconnection increased significantly between day 2 and day 21 and lasted beyond the 31 days of observation. Moreover, we tried to explain the stability of the networks obtained and showed that a small population of hGF in close vicinity of HUVEC networks expressed perivascular markers.

CONCLUSION

These findings highlight a new interesting property concerning hGF, accentuating their relevance in tissue engineering and periodontal regeneration. These promising results need to be confirmed using more 3D applications and in vivo testing.

Nucleotide lipid-based hydrogel as a new biomaterial ink for biofabrication

One of the greatest challenges in the field of biofabrication remains the discovery of suitable bioinks that satisfy physicochemical and biological requirements. Despite recent advances in tissue engineering and biofabrication, progress has been limited to the development of technologies using polymer-based materials. Here, we show that a nucleotide lipid-based hydrogel resulting from the self-assembly of nucleotide lipids can be used as a bioink for soft tissue reconstruction using injection or extrusion-based systems. To the best of our knowledge, the use of a low molecular weight hydrogel as an alternative to polymeric bioinks is a novel concept in biofabrication and 3D bioprinting. Rheological studies revealed that nucleotide lipid-based hydrogels exhibit suitable mechanical properties for biofabrication and 3D bioprinting, including i) fast gelation kinetics in a cell culture medium and ii) shear moduli and thixotropy compatible with extruded oral cell survival (human gingival fibroblasts and stem cells from the apical papilla). This polymer-free soft material is a promising candidate for a new bioink design.

Self-perceived educational needs of junior assistant professors in Conservative Dentistry and Endodontics in France

INTRODUCTION

Academic dental educators play a major role in training future dentists. They help students to develop medical knowledge and behavioural skills that improve the quality and rigor of their future practice. Therefore, their experience and knowledge are critical to ensure effective learning. However, a French national workshop revealed that most junior assistant professors lack educational skills at the beginning of their career. The aim of this study was to assess educational training needs of junior assistant professors in the Department of Conservative Dentistry and Endodontics.

MATERIALS AND METHODS

An electronic survey was sent to junior assistant professors belonging to Departments of Conservative Dentistry and Endodontics within the 16 French dental schools in 2016. This survey was designed to collect data regarding their motivations, teaching expertise and interest in pedagogy.

RESULTS

Sixty of the 69 junior educators turned in their answers, which represents a response rate of 87%. About 86.7% of respondents cited their attraction to teaching as one of the main reasons behind their application. The major difficulty encountered by junior faculty was related to course preparation. Only 15% had received educational training despite the fact that 98.3% were convinced of the usefulness of such a training for junior teachers.

CONCLUSION

This study identified the motivations and difficulties encountered by junior assistant professors. This collection of educational needs should be considered when planning a national programme for educational training of dental faculty that will promote the acquisition of teaching skills and improve the education of dental students.

Diagnosis and Management of Natal and Neonatal Teeth: Case Report of Three Newborns

Natal and neonatal teeth are rare features that can lead to various issues, from traumatic injuries and feeding difficulties to more severe problems, such as risk of aspiration due to excessive mobility of teeth. The purpose of this paper is to discuss the diagnosis and management of natal and neonatal teeth, and describe three cases of newborns with natal teeth. Decision processes and management are detailed regarding the specificity of each case. Periodic follow-up is recommended to maintain oral health and prevent any issues related to premature loss or eruption of primary teeth. A close collaboration between pediatricians and dentists should be considered in order to allow early diagnosis and efficient treatment.

Orofacial consequences of systemic sclerosis: A systematic review

Orofacial involvement is common and often understated in the treatment clinical guidelines of systemic sclerosis. It impairs daily life by having repercussions on comfort, nutrition, aesthetics and self-confidence. This review aimed at describing exhaustively the different orofacial consequences of systemic sclerosis. A systematic search was conducted using four databases (PubMed, Cochrane Library, Dentistry & Oral Sciences Source and SCOPUS) up to December 2016 according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses. Grey literature and hand search were also included. To be eligible for the inclusion, studies needed to meet the following criteria: randomised controlled trials, cross-sectional studies, case-control studies, pilot studies or cohort studies and full text available in English or French, with abstract. The studies had to concern at least 30 patients suffering from systemic sclerosis and having clinical and radiological oropharyngeal examination. The diagnosis of systemic sclerosis had to be determined according to precise recommendations; the retrieved oropharyngeal manifestations had to affect hard or soft tissues of the mouth and/or pharynx and needed to be evaluated with clinical measures. Study selection, risk bias assessment (Newcastle-Ottawa scale) and data extraction were performed by two independent reviewers. The retrieved features were microstomia and xerostomia associated with real hyposialia, temporomandibular joint symptoms, high caries experience, periodontal diseases as well as an increased risk of oral cavity and pharynx cancer. Early diagnosis enabling early management, prevention and oral hygiene is the key to avoid complicated and invasive procedures. Studies with higher level of evidence remain necessary to create standardised protocols.

Case Report of a Severe Recurrent Tongue Self-Injury in an Infant With Dystonia

Dystonia is characterized by sustained or intermittent muscle contractions causing abnormal, often repetitive movements, postures, or both that are typically patterned, twisting, and sometimes tremulous. It is often initiated or worsened by voluntary action and associated with overflow muscle activation. In this article we report a case of severe oromandibular dystonia, which is a specific form of dystonia characterized by involuntary, action-induced tonic or clonic spasms of the masticatory, lingual, and pharyngeal musculature. Episodes of repeated tongue biting in a 17-month-old girl caused her to stay in the PICU for 4 weeks. These episodes were the consequence of dystonia induced by a perinatal stroke. We highlight the specific dental management that enabled us to treat the child without extractions. Facing this type of complex illness, we insist on the importance of interdisciplinary work with the goal of avoiding outdated techniques. The use of botulinum toxin seemed relevant.