Evaluating the Effect of Attached Gingiva Height on Pre-implant Tissue

Background: Many patients refer to their load implants while there is no attached gingiva in the area of prosthetic implants – unlike the attached gingivae found with natural teeth. The important role played by gingiva in comforting the patient and preventing gingival inflammation has not been fully appreciated yet. This study aimed to evaluate the association between the attached gingival height with gingival inflammation and patients’ comfort. Methods: This retrospective cohort study was conducted to examine 80 implants (Dio uf) placed in 63 patients. At least two months had passed since the patients had had implant crown. The patients were divided into three groups: attached gingiva, gingival up to 2 mm, and at least 2 mm of attached gingiva. Indices such as bleeding on probing (BOP), the amount of plaque, gingival index and patient comfort during brushing and chewing were evaluated. Statistical data were analyzed using the Kolmogorov– Smirnov test, Levene’s test and independent t-test. Results: By increasing the height of attached gingiva, decreases were observed in probing depth (P value=0.004), BOP (P value=0.001), the degree of plaque index (P value=0.006), and gingival index (P value=0.003); and this association was statistically quite significant. By increasing the attached gingiva height, furthermore, the patients felt less discomfort when brushing and chewing; however, the findings were not statistically significant in terms of patients’ comfort during chewing (P value=0.364). Conclusions: Increasing the height of attached gingiva reduced the symptoms of gingival inflammation, but increased patients’ comfort when chewing and brushing.

MORPHOMETRY OF NECK-SHAFT ANGLE IN DRIED ADULT HUMAN FEMORA OF NORTH INDIAN POPULATION

Objectives: The present study aimed to record the femoral-neck shaft angle was carried out which would be of help to the orthopedicians while carrying out surgical repairs around the hip joint especially in fracture of the neck of femur. Materials and Methods: A total of 100 North Indian unpaired dry adult human femora (Right-50, Left-50) of unknown sex were studied. Neck-shaft angle (NSA) of the femur was measured with the help of goniometer and measurements were recorded in degrees. The raw data obtained were statistically analyzed. Range, mean, standard deviation, and standard error of mean were determined. Results: The mean NSA was found to be 127.63°+3.48° (Right=127.80°+3.56° and Left=127.46°+3.42°) with a range of 122°–137° (Right=122°–137° and Left=122°–136°). No significant difference in values of neck-shaft angle was found in the right and left femora. Conclusion: The overall goal of this study was to generate information that would be useful for geometric modeling of femora and collecting data which could prove useful for the development of prosthetic implants

Improvement of PMMA Dental Matrix Performance by Addition of Titanium Dioxide Nanoparticles and Clay Nanotubes

Over the last decades, several materials have been proposed for the fabrication of dental and mandibular prosthetic implants. Today, the poly(methyl-methacrylate) (PMMA) resin is the most spread material, due to its ease of processing, low cost, aesthetic properties, low weight, biocompatibility, and biostability in the oral cavity. However, the porous surface (which favors the adhesion of microorganisms) and the weak mechanical properties (which lead to wear or fracture) are the major concerns. The inclusion of engineered nanomaterials in the acrylic matrix could improve the performances of PMMA. In this study, we added two different kind of nanomaterials, namely titanium dioxide nanoparticles (TiO2NPs) and halloysite clay nanotubes (HNTs) at two concentrations (1% and 3% w/w) in PMMA. Then, we assessed the effect of nanomaterials inclusion by the evaluation of specific physical parameters: Young’s modulus, roughness, and wettability. In addition, we investigated the potential beneficial effects regarding the Candida albicans (C. albicans) colonization reduction, the most common yeast responsible of several infections in oral cavity. Our experimental results showed an improvement of PMMA performance, following the addition of TiO2NPs and HNTs, in a dose dependent manner. In particular, the presence of TiO2NPs in the methacrylate matrix induced a greater increase in PMMA stiffness respect to HNTs addition. On the other hand, HNTs reduced the rate of C. albicans colonization more significantly than TiO2NPs. The results obtained are of great interest for the improvement of PMMA physico-chemical properties, in view of its possible application in clinical dentistry.

Fundamentals of 3D Bioprinting Technology

3D bioprinting consists in the printing of synthetic 3D structures used as biomaterials, along with cells, growth factors, and other components necessary to create a new functional organ. This technology can be applied to regenerative medicine and tissue engineering to treat diseases, test pharmaceuticals, and study the mechanisms underlying diseases. Currently, there are three basic types of 3D bioprinting technologies: laser, droplet, and extrusion. Laser-based bioprinters (LBP) use laser energy to induce the bioink transfer. Droplet-based bioprinters (DBP) expel the bioink dropwise throughout a nozzle. Inkjet-based bioprinters are the DBP commonly used for biological proposes, it is also a non-contact approach that releases controlled volumes of bioink drops in a continuous (CIJ) or under demand way (DOD). The extrusion-based bioprinters (EBB) also use pressure to force out the bioink, but consists of a syringe containing the material with a pneumatic or mechanical mechanism as dispensing system. Comparing to the other bioprinting technologies, extrusion printing is the most versatile and is indicated for bioprinting of scaffold prosthetic implants. The bioinks used in 3D bioprinting are composed of a solution with a biomaterial mixture, usually encapsulating cells. Biomaterials are essential components of 3D bioprinting technologies because they provide scaffolds as supporting physical structures for cells to attach, grow, differentiate, and develop into tissues. Numerous cell types have been used in 3D bioprinting to build cardiovascular, musculoskeletal, neural, hepatic, adipose and skin tissues. Bioprinting is an emerging technology that has the ability to revolutionize the way we address many health issues.

Biomimetic Prosthetic Hand Enabled by Liquid Crystal Elastomer Tendons

As one of the most important prosthetic implants for amputees, current commercially available prosthetic hands are still too bulky, heavy, expensive, complex and inefficient. Here, we present a study that utilizes the artificial tendon to drive the motion of fingers in a biomimetic prosthetic hand. The artificial tendon is realized by combining liquid crystal elastomer (LCE) and liquid metal (LM) heating element. A joule heating-induced temperature increase in the LCE tendon leads to linear contraction, which drives the fingers of the biomimetic prosthetic hand to bend in a way similar to the human hand. The responses of the LCE tendon to joule heating, including temperature increase, contraction strain and contraction stress, are characterized. The strategies of achieving a constant contraction stress in an LCE tendon and accelerating the cooling for faster actuation are also explored. This biomimetic prosthetic hand is demonstrated to be able to perform complex tasks including making different hand gestures, holding objects of different sizes and shapes, and carrying weights. The results can find applications in not only prosthetics, but also robots and soft machines.

Anthropometry of the knee of the Turkish population and the comparison to implant sizes in total knee arthroplasty

BACKGROUND: Total knee arthroplasty (TKA) is one of the most common orthopaedic surgical procedures in the advanced stages of knee arthritis. OBJECTIVE: The purpose of this study was to define the sex differences in the Turkish population’s morphological measurements of the distal femoral and proximal tibial surfaces that form the knee joint and to compare their compatibility with conventional prosthetic implants commonly used in TKA for advanced-stage knee arthritis. METHODS: Anthropometric data for a total of 240 knees from 240 patients were measured using 3-dimensional computed tomography (3D CT). All morphological data were compared with the dimensions of four conventional knee prostheses commonly used in Turkey. RESULTS: A comparison of the four tibial components revealed that the majority of female proximal tibias matched with smaller-sized tibial components, whereas those of males matched the larger sizes. Comparing the morphological data with similar values for the four femoral components currently used in Turkey, we found that all the prostheses had similar values. CONCLUSION: The four conventional prosthetic brands included in this study matched the distal femoral dimensions of both sexes. On the other hand, we need smaller size tibial components for our female population.

A finite element analysis approach to predicting intramedullary pressure during the insertion of prosthetic implants

Fat embolism syndrome is a serious post-operative complication of orthopaedic procedures such as fracture fixation and total joint replacement. Fat embolism syndrome can be a result of increased intramedullary pressure during the insertion of prosthetic implants in long bones. A macro was developed that automates the creation of finite element models representing a simplified bone/fluid/implant system and a hammering event. The finite element models were validated by computing the peak stresses at various locations in the bone and comparing them to pressures measured at similar locations in experimental tests. Finite element models were used to test the effect of using hollow implants on intramedullary pressure in the bone, in some cases yielding an average reduction of 19.1%. It has been shown that it is acceptable to use finite element models for such parametric studies and that hollow implants have the potential to decrease intramedullary pressure during insertion.

A finite element analysis approach to predicting intramedullary pressure during the insertion of prosthetic implants

Fat embolism syndrome is a serious post-operative complication of orthopaedic procedures such as fracture fixation and total joint replacement. Fat embolism syndrome can be a result of increased intramedullary pressure during the insertion of prosthetic implants in long bones. A macro was developed that automates the creation of finite element models representing a simplified bone/fluid/implant system and a hammering event. The finite element models were validated by computing the peak stresses at various locations in the bone and comparing them to pressures measured at similar locations in experimental tests. Finite element models were used to test the effect of using hollow implants on intramedullary pressure in the bone, in some cases yielding an average reduction of 19.1%. It has been shown that it is acceptable to use finite element models for such parametric studies and that hollow implants have the potential to decrease intramedullary pressure during insertion.

Multi-mechanistic Monoclonal Antibody Combination Targeting Key Staphylococcus aureus Virulence Determinants in a Rabbit Model of Prosthetic Joint Infection

In a rabbit model of methicillin-resistant S. aureus prosthetic joint infection, prophylaxis with AZD6389*—a combination of three monoclonal antibodies targeting alpha-hemolysin, bicomponent cytotoxins (LukSF/LukED/HlgAB/HlgCB), and clumping factor A—resulted in significant reductions in joint swelling, erythema, intra-articular pus, and bacterial burden in synovial tissues and biofilm-associated prosthetic implants when compared with isotype-matched control IgG. Targeting specific staphylococcal virulence factors could thus have potential clinical utility for prevention of prosthetic joint infection.