Abstract:There is a growing interest in the development of organic nanomaterials for biomedical applications. An increasing number of studies focus on the uses of nanomaterials with organic structure for regeneration of bone, cartilage, skin or dental tissues. Solid evidence has been found for several advantages of using natural or synthetic organic nanostructures in a wide variety of dental fields, from implantology, endodontics, and periodontics, to regenerative dentistry and wound healing. Most of the research is concentrated on nanoforms of chitosan, silk fibroin, synthetic polymers or their combinations, but new nanocomposites are constantly being developed. The present work reviews in detail current research on organic nanoparticles and their potential applications in the dental field.

Poly(lactic-co-glycolic acid) or PLGA is a biodegradable polymer used in a wide range of medical applications. Specifically PLGA materials are also developed for the dental field in the form of scaffolds, films, membranes, microparticles, or nanoparticles. PLGA membranes have been studied with promising results, either alone or combined with other materials in bone healing procedures. PLGA scaffolds have been used to regenerate damaged tissues together with stem cell-based therapy. There is solid evidence that the development of PLGA microparticles and nanoparticles may be beneficial to a wide range of dental fields such as endodontic therapy, dental caries, dental surgery, dental implants, or periodontology. The aim of the current paper was to review the recent advances in PLGA materials and their potential uses in the dental field.

The temporomandibular joint (TMJ), the most complex and evolved joint in humans, presents two articular surfaces: the condyle of the mandible and the articular eminence (AE) of the temporal bone. AE is the anterior root of the zygomatic process of the temporal bone and has an anterior and a posterior slope, the latter being also known as the articular surface. AE is utterly important in the biomechanics of the TMJ, as the mandibular condyle slides along the posterior slope of the AE while the mandible moves. The aim of this review was to assess significant factors influencing the inclination of the AE, especially modifications caused by aging, biological sex or edentulism. Studies have reported variations in the angles of the slopes of the AE between medieval and recent human dry skulls, as well as between subjects of different racial origin. Recent articles have emphasized the significant role that tooth loss has on the flattening of the AE. Although some papers have described biological sex or age as factors which could be associated with differences in AE angulations, edentulism seems to be a significant factor impacting on the inclination of the AE.

Background : The mandibular foramen (MF) is the anatomic landmark where the interior alveolar nerve enters the mandibular ramus, and the area of choice where anesthesia of this nerve is performed. The position of the MF can vary, and accurately establishing its location and topographic variations is of great importance for the successful anesthesia of the inferior alveolar nerve. Materials and Methods : We carried out two morphometric ex vivo studies concerning the topography of the MF, on dry human mandibles coming from dentate and completely edentulous human subjects of known age and gender and an in vivo morphometric study, through cone-beam computed tomography (CBCT) scans, concerning the topography of the MF in human subjects having Kennedy Class I mandibular edentulism. The morphological characteristics we investigated were: the distance between the MF and the anterior margin of the mandibular ramus (MF–AM distance), the distance between the MF and the posterior margin of the mandibular ramus (MF–PM distance), the distance between the MF and the inferior margin of the mandibular ramus (MF–IM distance), the distance between the MF and the temporal crest of the mandibular ramus (MF–TC distance), the distance between the MF and the superior margin of the mandibular ramus (MF–SM distance), and the vertical and transverse diameters of the MF. The results were statistically processed in Stata/MP13 software package using Student’s t -test and two-way analysis of variance (ANOVA). Results : Through direct morphometry on dentate dry human mandibles, the MF–AM and the MF–SM distances showed statistically significant differences for age, gender and for interactions, while the MF–PM and MF–IM distances showed statistically significant differences for age and for interactions. In the case of the MF–TC distance, the only significant difference observed was for the gender. No statistical significance was found for side, age, gender, and interactions in the cases of MF vertical and transverse diameters. Through direct morphometry on completely edentulous dry human mandibles, the MF–PM and MF–SM distances showed statistically significant differences for age, gender and for interactions, while the MF–AM, MF–IM, and MF–TC distances, as well as the MF vertical and transverse diameters showed statistically significant differences for age and for model (interactions). The results showed that MF is 2 mm closer to the anterior margin of the mandibular ramus after having lost teeth. Through imaging morphometry, the MF–PM distance and the vertical diameter of MF showed statistically significant differences for age, gender and for interactions, while the MF–AM, MF–IM, MF–SM and MF–TC distances, as well as the transverse diameter of MF showed statistically significant differences for age and for interactions. Comparing the results obtained by the three studies, we found no statistically significant diff...

Alveolar ridge augmentation with autogenous bone grafts is a frequent procedure used in Implant Dentistry. This paper presents an immunohistochemical assessment of the integration of mandibular autografts, applied in maxillary bone defects. Seven adult dogs were used in the study. The work methodology was established through maxillary and mandibular morphometry. The posterior mandibular body was considered the donor region and the lateral region of the maxilla the recipient area. Bilateral maxillary bone defects were performed on the predetermined receiving sites, which were later augmented with mandibular grafts. Fragments of hard tissue from the grafted sites were harvested 90-100 days after the surgical interventions and immunohistochemically evaluated. The immunohistochemical study proved the existence of bone regeneration in the case of mandibular corticocancellous autografts applied at the maxillary level, being an efficient procedure for assessing their integration.

Temporomandibular joint (TMJ) changes are quite frequent in adults, but not all changes are degenerative. A high prevalence of bone alterations in the TMJs was reported by different research groups. Disturbed remodeling of bony articulating structures occurs because of overloading masticatory forces or because the mechanical loading in the area out-weighs the adaptive capacity of the TMJ structures. Although most of the degenerative TMJ alterations are identified at the level of the condylar process, a complete evaluation of the degenerative modifications encountered in the temporal TMJ region should not be forgotten as they are important for a comprehensive assessment and further management of the clinical situation. Several research groups have described osseous remodeling in the temporal component of the TMJ. Evidence is scarce for degenerative modifications at the level of the articular eminence and thickening of the roof of the glenoid fossa has been associated with osteoarthritis.

Silk fibroin is an organic polymer isolated from cocoon silk fibers. Recently it has been studied as a substrate for tissue engineered cartilage, bone , ligaments, nerves, cornea and also for drug delivery applications. The current review focuses on recent advance in silk fibroin and its potential uses in regeneration therapies, mainly in the dental field. Data extraction was carried out according to the standard Cochrane systematic review methodology and the following databases were used: PubMed, Google Scholar, Medline and the Google library. Out of the 151 related articles that were critically assessed, only 57 articles were included in the critical appraisal. There is evidence that silk fibroin is a biocompatible polymer and has been proved to be cytocompatible with a wide variety of cells. Composite silk fibroin with hydoxyapaptite, bioglass, gold or silica can be used in a variety of applications. Regenerative dentistry may profit from the silk fibroin due to possible future uses in implant therapy, mineralized tissue formation or healing of the wounds of the buccal mucosa.

Oral epithelial differentiation is known to be directed by underlying fibroblasts, but the responsible factor(s) have not been identified. We aimed here to identify fibroblast‐derived factors responsible for oral epithelial differentiation. Primary normal human oral keratinocytes and fibroblasts were isolated from healthy volunteers after informed consent (n = 5) and 3D‐organotypic (3D‐OT) cultures were constructed. Various growth factors were added at a range of 0.1‐100 ng/ml. 3D‐OTs were harvested after ten days and assessed histologically, by immunohistochemistry and the TUNEL method. Epithelium developed in 3D‐OT without fibroblasts showed an undifferentiated phenotype. Addition of granulocyte macrophage‐colony stimulating factor (GM‐CSF) induced expression of cytokeratin 13 in suprabasal cell layers. Admixture of GM‐CSF and keratinocyte growth factor (KGF) induced, in addition, polarization of epidermal growth factor (EGF) receptor and β1‐integrin to basal cell layer and collagen IV deposition. Terminal differentiation with polarization of TUNEL‐positive cells to superficial layers occurred only in the presence of fibroblasts in collagen gels either in direct contact or at distance from normal oral keratinocytes. Taken together, these results show that major aspects of oral epithelial differentiation are regulated by the synergic combination of GM‐CSF and KGF. However, the terminal stage seems to be controlled by other yet unidentified fibroblast‐derived diffusible factor(s).