Background: Dental implants emerge as a dependable and efficacious alternative for patients experiencing partial or complete tooth loss. The stability of these implants is influenced by surface topography and macro-level design. In cases where the height of the maxillary posterior region is diminished, employing short implants can prove advantageous. With the aim of examining the distribution of von Mises stress, strain, and micromovement in D4 bone quality surrounding platform-switched short implants, measuring 6 mm in length and featuring diameters ranging from 4 to 6 mm, as well as different thread designs, an in-depth finite element analysis was conducted under immediate loading conditions. Methodology: A 3D finite element model was constructed to simulate maxillary molar crowns, incorporating an implant with a length of 6 mm and varying diameters and thread designs. The diameters utilized were 4/3.6 mm, 5/4 mm, and 6/4.8 mm, while the thread designs included buttress, square, and triangle patterns. Each model underwent analysis with a 100 N force applied in two directions: vertical and oblique, relative to the long axis of the implant. Stress, strain, and micromovement in the peri-implant region were recorded, employing the Ansys Workbench R v.18.1 software for modelling and analysis. Results: When comparing all three diameters, the wide diameter (6 mm threads) exhibited the lowest values of peri-implant von Mises stresses (3.3 MPa and 35.1 MPa), strains (194 Ɛ and 484 Ɛ), and micromovements (0.7 μm and 1.3 Ɛ) subjected to axial and non-axial loading of a 100 N force. Notably, square microthreads yielded the most favorable stress parameters among the different thread shapes, manifesting the minimum values of stress, strains, and micromovements in their vicinity. Conclusion: For the treatment of atrophic ridges or in scenarios necessitating extensive surgical preparation of the implant site, a combination of short implants, wide diameters, and platform switching can be employed. In situations with reduced bone height and the requirement for an implant-supported prosthesis to replace a missing permanent maxillary molar, the utilization of wide-diameter platform-switched short implants measuring 6 mm in length, featuring a square thread design, should be taken into consideration.

Stem cells from human exfoliated deciduous teeth (SHEDs) are considered a type of mesenchymal stem cells (MSCs) because of their unique origin from the neural crest. SHEDs can self-renewal and multi-lineage differentiation with the ability to differentiate into odontoblasts, osteoblast, chondrocytes, neuronal cells, hepatocytes, adipocytes, etc. They are emerging as an ideal source of MSCs because of their easy availability and extraordinary cell number. Ascorbic acid, or vitamin C, has many cell-based applications, such as bone regeneration, osteoblastic differentiation, or extracellular matrix production. It also impacts stem cell plasticity and the ability to sustain pluripotent activity. In this study, we evaluate the effects of ascorbic acid on stemness, paracrine secretion, and differentiation into osteoblast, chondrocytes, and adipocytes. SHEDs displayed enhanced multifaceted activity, which may have applications in regenerative therapy.

Titanium is the main component of dental implants. It is also routinely used as a framework material for implant-supported full-arch prostheses due to its low density, biocompatibility, and other mechanical properties. Remarkable mechanical properties such as lesser mass density and higher young’s modulus of graphene have gained popularity among scientists, improving the properties of biomedical implants. Thus, our study aimed to compare the outcome through the von Mises stresses generated on All-on-6 and All-on-3 implant models, as well as on the framework, and evaluate the effect of stress patterns on the crestal bone around implants in the mandible. FEA (Finite Element Analysis) study was carried out using edentulous mandible models. Four 3D FEA models with 3 and 6 implants were used (Model 1: Titanium bar-supported 6 straight implants; Model 2: Graphene bar-supported 6 straight implants; Model 3: Titanium bar-supported 3 implants with 30 degrees-tilted; Model 4: Graphene bar-supported 3 implants with 30 degrees-tilted) in order to simulate endosseous implant designs. The implant measuring 4.2 mm in diameter and 11.5 mm in length were used. The most distal implants in the 3-implant models were placed with angulation of 30 degrees; in 6 implants, they were vertically placed. All the models were analyzed for vertical and oblique axis with a single force magnitude of 100 N. In all four implant models and under loading conditions, the peak stress points were always on the neck of the most distal implant. von Mises stresses were within the normal stress range. In a conventional six-straight implant model supported by a titanium framework, the cortical stress in the region of implants was 25.27 MPa, whereas, in the graphene framework, it was 12.18 MPa. Under vertical load, there was a significant difference in the cortical stress around the tilted implants (30 degrees) in the 3-implant system of titanium and graphene frameworks, respectively, 70.31 MPa and 21.27 MPa. The graphene framework demonstrated better results than the titanium framework for the conventional six-implant system under vertical load, achieving stress of 30.09 MPa and 76.60 MPa, respectively. In the case of the 3-implant system, a significant difference in the bar stress was observed between graphene and titanium, respectively, 256.32 MPa and 180.1 MPa of bar stress. Within the limitation of this study, the peri-implant stresses were decreased using graphene framework models. Hence, it was possible to conclude that the best load-bearing capacity results were found in the graphene framework group compared to the titanium framework for All-on-6 and All-on-3 implant models, even though both materials are reliable options used as framework materials in implant-supported full-arch prostheses.

The essential factor in determining the preservation of restoration is the marginal seal. Restoring cervical lesions with a resin composite has always been a challenge. Composite resins with various viscosities and different bonding systems are being researched to reduce the microleakage. Confocal laser scanning microscopy (CLSM) is the latest non-destructive technique for visualizing the microleakage. Objectives: To evaluate and compare the microleakage of Universal Flo composite resin (G-aenial) using etch and rinse adhesive system ER-2 steps (Adper Single Bond 2), self-etch adhesive system SE-1 step (G-Bond), and self-adhesive flowable composite resin (Constic) in Class V cavities using a confocal laser scanning microscope. Materials and Method: Class V cavities were prepared on 27 caries-free human extracted premolar teeth on the buccal and lingual surfaces with standardized dimensions of 2 mm height, width 4 mm, and a depth of 2 mm. After the cavity preparation, all teeth were randomly divided into three groups, namely Group-I: G-aenial Universal Flo with Single Bond 2 (n = 9 teeth); Group-II: G- aenial Universal Flo with G-Bond (n = 9 teeth), and Group-III: Constic (n = 9 teeth). The prepared and restored specimens were then subjected to thermocycling for 500 cycles in a water bath at 5 °C and 55 °C with a dwelling time of 30 s. The specimens were placed in 0.6% aqueous rhodamine dye for 48 h. Sectioning was carried out bucco-lingually and specimens were evaluated for microleakage under a confocal laser scanning microscope. Results: There was a significant difference (p = 0.009) in microleakage when comparing total etch and rinse, specifically between Adper Single Bond 2 ER-2 steps (fifth generation) and self-adhesive flowable composite resin, which is Constic. There was more microleakage in the self-etch bonding agent, particularly G-Bond, SE-1 step (seventh generation), when compared to ER-2 steps (fifth generation bonding agent); however, the results were not statistically significant (p = 0.468). The self-adhesive flowable composite resin showed more microleakage than SE-1 step and ER-2 steps. Conclusions: None of the adhesive systems tested were free from microleakage. However, less microleakage was observed in the total etch and rinse, especially Adper Single Bond 2 (ER-2 steps), than the self-etch adhesive system SE-1 step and self-adhesive flowable composite resin. Clinical significance: Constant research and technological advancements are taking place in dentin adhesives to improve the marginal seal. This has led to the evolution of total acid-etching dentin bonding agents termed as etch and rinse (ER)-2 steps (fifth generation dentin bonding agents) and self-etching (SE) 2 steps, and SE-1 step dentin bonding agents termed as the sixth and seventh generation bonding agents, respectively.

Background: Stem cell therapy has become an advanced and state-of-the-art procedure to regenerate lost tissues of the human body. Cartilage repair is a challenging task in which stem cells find potential application. One of the important biologic modifiers that can cause chondrogenic differentiation of stem cells is taurine. However, taurine has not been investigated for its effects on dental pulp derived stem cell (DPSC) chondrogenic differentiation. Objective: The objective of the study was to investigate if taurine administration to DPSCs heralds chondrogenic differentiation as ascertained by expression of SOX9, COL2A1, ACAN, ELN, and COMP. The study also investigated if the differentiated cells synthesized glycosaminoglycans, a marker of cartilage formation. The study also aimed to assess proliferative activity of the cells after taurine administration by measuring the hTERT gene and protein expression. Materials and methods: DPSCs were obtained from a molecular biology laboratory and characterization of stem cell markers was done by flow cytometry. The cells were subjected to a MTT assay using various concentrations of taurine. Following this, hTERT gene and protein estimation was done in the control, telomerase inhibitor treated DPSC (TI-III), 10 μM taurine treated DPSC, and TI-III + 10 μM taurine treated DPSCs. A polymerase chain reaction was done to assess gene expression of SOX9, COL2A1, ACAN, ELN, and COMP genes and glycosaminoglycans were estimated in control cells, Induced DPSCs, induced and TI-III treated DPSCs, and 10 μM taurine treated DPSCs. Results: DPSCs expressed CD73, CD90, and CD105 and did not express CD34, CD45, and HLA-DR, which demonstrated that they were mesenchymal stem cells. The MTT assay revealed that various concentrations of taurine did not affect the cell viability of DPSCs. A concentration of 10 μM of taurine was used for further assays. With regard to the hTERT gene and protein expression, the taurine treated cells expressed the highest levels that were statistically significant compared to the other groups. Taurine was also found to restore hTERT expression in telomerase inhibitor treated cells. With regard to chondrogenesis related genes, taurine administration significantly increased the expression of SOX9, COL2A1, ACAN, and ELN genes in DPSCs and caused a significant increase in glycosaminoglycan production by the cells. Conclusions: Taurine can be regarded a biologic modifier that can significantly augment chondrogenic differentiation of DPSCs and can find potential applications in regenerative medicine in the area of cartilage regeneration.

Background: It is essential for practicing dentists to have adequate knowledge of HIV/AIDS and its implications in the dental practice. Their attitudes should also be up to the professional expectations. This study aimed to assess knowledge of HIV/AIDS infection and attitudes towards its patients among dental students in Saudi Arabia. Methods: A questionnaire was prepared and distributed among a sample of dental students in Saudi Arabia. Twenty questions related to knowledge, attitudes, and oral manifestation of HIV were presented. Results: A total of 405 questionnaires were completed (67% response rate). Participants showed low knowledge of safety regarding HIV (39.5%) and 44.2% indicated that they would take an HIV test after needle stick injury. The proportion of correct answers regarding transmission of HIV through saliva, cardiopulmonary resuscitation, and aerosols by hand pieces was 41%, 37.5%, and 26.4%, respectively. Almost 50% of the surveyed dental students expressed unwillingness to treat HIV-positive patients. Poor knowledge was noted regarding oral manifestations of HIV (32.7%). Of the participants, 57.8% indicated that infection control procedures are very important for the treatment of HIV patients and 50.6% believed that a dentist can make a decision to reject the treatment of HIV patients. According to the participating dental students, the three major oral manifestations in HIV patients are hairy leukoplakia (47.4%), oral candidiasis (44.7%), and Kaposi’s sarcoma (43.5%). Conclusion: Inadequate knowledge and unprofessional attitude towards HIV/AIDS patients were identified among this group of dental students in Saudi Arabia. Dental educators and health care planners in Saudi Arabia should plan to promote the knowledge and attitudes of dental students in Saudi Arabia towards the treatment of HIV patients.