Prosthesis

The objective was to compare the repeatability between dental faculty, whose clinical practice was primarily restorative dentistry, and final year dental students in categorizing the inherent translucency of images selected at random using either a 3- or 7-point scale (translucent to opaque). Digital images of anterior dentition were randomly selected based on inherent translucency. Thirty images (five were repeated) were randomized and categorized by 20 dental students and 20 faculty on their inherent translucency. Statistical analysis was performed using an F test for analysis of variance at 95% confidence interval. A covariance parameter estimate (CPE) was accomplished to compare the inter-rater variability of the dental faculty and dental students. Statistically, more variability occurred between Slides (CPE of 0.185 (p = 0.001)) and between Subject and Slide (CPE of 0.122 (p = 0.0002)) than within subjects (CPE of 0.021 (p = 0.083)). Viewing repeat Slides, Students (CPE = 0.16) were more consistent (p < 0.05) than faculty (CPE = 1.8) using the 3- point scale, while the CPE was the same (CPE = 0.669) using 7-point scale. Dental students and faculty were consistent using the 7-point scale to judge repeat slides, while dental students in this limited pilot study were more consistent when viewing a repeat slide using the 3-point scale. Full article

Medical device regulations are dynamic, as they need to cover an ever changing landscape. In Europe this has led to a new set of regulations (both for Medical Devices and In Vitro Diagnostics), which replaced the old rules. This study is interested in how the complexity of these medical regulations changed over time and if additional time-based metrics can be associated with any of the complexity metrics. Complexity is defined in terms of readability of the text and it is computed using established linguistic measures, as well as Halstead complexity scores. It was shown that the regulatory complexity of new EU medical device regulations was higher than their predecessors, especially when Halstead complexity measures were considered. The complexity metrics obtained for the new regulations were subsequently associated with the time it took to consider these regulations. Only very weak Pearson’s correlation coefficients were found between the complexity scores and the obtained response times for the new regulations. This could indicate that there are issues with how complexity is perceived by those that need to apply these regulations. Taking the complexity of regulations into account can greatly help with the development of more user friendly regulations. The results from the data-driven methods that are applied in this research indicate that governments could benefit from focusing on making regulations more accessible and utilitarian. This would improve the stakeholder adherence and facilitate effective implementation. This work also highlighted the need to develop more suitable methods to analyse regulatory text to further inform the wider research community. Full article

The purpose of this study is to numerically analyze a 3D model of an implant under fatigue loads. A bone and a V shape implant were modeled using SolidWorks2008 software. In order to obtain an exact model, the bone was assumed as a linear orthotropic material. Mechanical loads were applied in terms of fastening torque to the abutment and mastication force applied at the top of the crown. The abutment was tightened into the implant by applying a 35 N.cm torque causing tensile stress within the abutment screw as a preload that is harmful not only for the fatigue life of the abutment, but also for the stability of the implant-abutment interface. A 700 N force at an angle of 30 degrees to the vertical direction was applied to the crown. The mechanical analysis results showed that the abutment is the critical component of the implant system in terms of fatigue failure. This is due to the fact that the tensile preloads originated from the fastening torque. The results were presented in terms of fatigue life in the abutment. Fatigue life of the abutment and implant were calculated based on the Goodman, Soderberg, Smith–Watson–Topper (SWT), and Marrow theories. According to the results of the fatigue life prediction, abutment screws may fail after about 3 × 10⁵ cycles. The predicted results by the Goodman theory are at a very good accordance with the clinical data. Full article

Functional, comfortable prosthetic limbs depend on personalised sockets, currently designed using an iterative, expert-led process, which can be expensive and inconvenient. Computer-aided design and manufacturing (CAD/CAM) offers enhanced repeatability, but far more use could be made from clinicians’ extensive digital design records. Knowledge-based socket design using smart templates could collate successful design features and tailor them to a new patient. Based on 67 residual limb scans and corresponding sockets, this paper develops a method of objectively analysing personalised design approaches by expert prosthetists, using machine learning: principal component analysis (PCA) to extract key categories in anatomic and surgical variation, and k-means clustering to identify local ‘rectification’ design features. Rectification patterns representing Total Surface Bearing and Patella Tendon Bearing design philosophies are identified automatically by PCA, which reveals trends in socket design choice for different limb shapes that match clinical guidelines. Expert design practice is quantified by measuring the size of local rectifications identified by k-means clustering. Implementing smart templates based on these trends requires clinical assessment by prosthetists and does not substitute training. This study provides methods for population-based socket design analysis, and example data, which will support developments in CAD/CAM clinical practice and accuracy of biomechanics research. Full article

Implants fracture is a rare but possible complication that leads to implants failure after prostheses delivery. Mechanical properties play a key role in the failure of dental implant systems. The aim of this narrative review was to evaluate the existing evidence in identifying etiology risk factors for implants fracture. The focused question was to evaluate whether there was any possible factors influencing the fracture of dental implants. A literature search of papers written in English, published from 1967 to July 2021, and reporting incidence of implants fracture in human with at least 15 participants (and one year of follow-up) was conducted using PubMed database including MeSH and free text terms and filters. Selected manuscripts were analyzed and discussed. The outcomes were the incidence of implants failure due to a fracture and the associated risk factors. A total of 96 articles were initially selected, but only eight articles were included according to the search criteria (two systematic reviews and six retrospective evaluation). Incidence of implants fracture ranged from 0.2 to 2.3%, with a mean value of 0.52%. Poor implant planning, including implant design and diameter, and occlusal overloading, were the most common variables associated with implants fracture. Implant removal is the only possible treatment and hence prevention, including stability of the marginal bone loss, is mandatory. Full article

Unfamiliarity with medical device regulations can sometimes be a barrier to deploying technology in a clinical setting for researchers and innovators. Health service providers recognise that innovation can happen within smaller organisations, where regulatory support may be limited. This article sets out to increase transparency and outline key considerations on medical device regulations from a UK healthcare provider’s perspective. The framework used by Guy’s and St Thomas’ NHS Foundation Trust (GSTFT) for assessing research devices is presented to give an overview of the routes that R&D medical devices take to enter a clinical setting. Furthermore, current trends on research studies involving medical devices were extracted from the GSTFT internal R&D database and presented as the following categories (i) commercial vs. non-commercial, (ii) assessment type and (iii) software vs. non-software. New medical devices legislation will be introduced within the UK in July 2023. It is anticipated regulating software as a medical device may become more challenging for healthcare providers and device manufacturers alike. It is therefore important for different stakeholders involved to work together to ensure this does not become a barrier to innovation. Full article

In oral rehabilitation, the treatment of partial edentulism (PEd) is performed by removable partial dentures (RPD) or assembled prosthetic works (APW) composed of several components, fixed to the prosthetic field (Pa) and a removable one (Pb), in order to facilitate the daily hygiene but also the damping of the occlusal forces applied in mastication. Cobalt-Chromium alloys are materials used to manufacture modern prosthetic assembles. In order for this study to be relevant, it was necessary to standardize the design of the framework (Pa) in terms of shape and volume so that the experiment could be reproducible for the five Co-Cr alloys: 0-A (Co-Cr-Mo), 5-A and 10-A (Co-Cr-Mo-W), 15-A and 16.4-A (Co-Cr-W-Fe) and for the three fabrication methods of dental assembled prosthetic frameworks: refractory duplicate method (RD) resulting removable framework (Pb), direct construction method (DC) resulting removable framework (Pb-) and casting over metal method (CoM) resulting removable framework (Pb+). The time allocated to the adaptation process (AP), mechanical processing and sandblasting, in order to assemble the two components was between 43–70 min, even though the assembly between the Pa-framework and the complementary framework (Pb+) was not necessary, CoM-method hs been provide the elimination of AP step. By applying the arithmetic simple rule of three, the percentages for each of the three methods used were calculated, the values of the difference were obtained. The CoM method improves the joining precision between the components of the removable assembly of prosthetic frameworks by 91.7% compared to the RD method and by 80.62% compared to the DC method. According to the efficiency of the methods used in the precision of joining between frameworks components, their order is: casting over metal, direct construction and refractory duplicate method. Full article

Fabrication of complete dentures (CDs) utilizing computer-aided design and computer-aided manufacturing (CAD/CAM) methods has attracted a lot of attention. The purpose of this paper was to summarize current knowledge about digital CDs and the relevant technology, and to present the application of the new technology in a dental geriatrics case. Initially, some of the challenges regarding digitization of the oral mucosa as a supporting surface of the CDs’ intaglio surface are listed. Next, a brief introduction of the CAD software capabilities regarding CDs is presented. The latest CAM additive and subtractive techniques for CDs are following. Subsequently, the consecutive steps for the construction of a digital CD as part of the prosthodontic treatment of a 90-year-old ambulative female patient are presented. Finally, some considerations about the digital workflow in CD manufacturing are discussed. In conclusion, the new digital technology has clear advantages; however, implementation requires careful planning. The digital workflow is applicable and versatile. Full article

In recent years, medical device regulatory bodies have recognised software-as-a-medical-device (SaMD) as a distinct subgroup of devices. The field of SaMD has been rapidly evolving and encompasses a range of different digital solutions. Many organisations have now started to look into digital healthcare, as a way to solve key global challenges. However, there remains uncertainty regarding how many of these SaMD products are entering the market and to what extent these systems achieve a desired level of general safety once they are in the market. In this study, we utilise data collected from publicly available databases. The data are evaluated for trends and a descriptive analysis is performed of the recall and adverse events associated specifically with SaMD. We find that there is a significant positive trend (p < 0.05) of SaMD registrations, although the number of SaMD registrations remains relative low compared to non-SaMD. This rise in SaMD registrations coincides with increasing levels of recalls and adverse events. More importantly, it becomes apparent that adverse events notification is not yet fit for purpose with regards to SaMD. Full article

Dental implants represent the gold standard for the treatment of single edentulism, even in anterior areas. Today, the basic criteria for implant success has changed from mobility, pain, radiolucency, and peri-implant bone loss (>1.5 mm) to prosthetic level success, aesthetics, soft tissue parameters, as well as patient satisfaction. This case report documents a combination of surgical and prosthetic procedures for the treatment of gingival recessions in the anterior maxilla, appearing after tooth extraction, socket preservation, and staged guided implant placement. Prosthetic management of the temporary restoration, orthodontic treatment, and a connective tissue graft were performed. The decision-making process and step-by-step execution of the treatments are presented to describe the entire clinical and surgical management of the reported case. Finally, good aesthetic outcomes, patient satisfaction, and recovery of the soft tissue recession were observed with the combination of these techniques. Full article

Dental fluorosis is a common disorder caused by excessive fluoride intake during tooth development. The esthetic consequences of dental fluorosis can negatively affect oral health-related quality of life and have lasting psychosocial effects. In severe cases, where the fluorosed enamel is prone to chipping, flaking, and developing caries, minimally invasive procedures are ineffectual and a more substantial restorative approach is required to restore optimal function and esthetics. However, no definitive guidelines exist for the management and treatment of severe dental fluorosis due to the limited evidence available in the literature. This case report describes the full-mouth rehabilitation of a patient with severe dental fluorosis utilizing adhesively bonded all-ceramic crowns, veneers, and overlays. The successful follow-up on this case indicates that adhesively bonded restorations may provide a viable option in the functional and esthetic management of severely fluorosed dentition. Full article

The outcomes of prosthetic rehabilitation after lower limb loss are, in large part, affected by the effectiveness of the provided gait retraining. The noted prevalence of adverse long-term effects, such as further joint and muscle degeneration, suggests that traditional rehabilitation programs have limitations. Recent advances in technology and in the understanding of motor learning promise the potential for better gait retraining interventions. This article reviews current literature on systems and methodologies of improving gait parameters in those with lower limb prostheses via exercise programs and various biofeedback systems. A total of 13 articles were included in the qualitative analysis. Findings indicate that many of the investigated systems are able to effectively analyze and change gait in the target population, but there remain considerable gaps in the knowledge. It has been noted that feedback modalities and dosage must be customized based on patient characteristics and rehabilitation goals, yet there is currently not enough published evidence to inform such customization. Full article

Different all-ceramic crown designs are available to perform indirect restoration; however, the mechanical response of each model should still be elucidated. The study aims to evaluate the stress distribution in three different zirconia crown designs using finite element analysis. Different three-dimensional molar crowns were simulated: conventional bilayer zirconia covered with porcelain, a monolithic full-contour zirconia crown, and the cutback modified zirconia crown with porcelain veneered buccal face. The models were imported to the computer-aided engineering (CAE) software. Tetrahedral elements were used to form the mesh and the mechanical properties were assumed as isotropic, linear and homogeneous materials. The contacts were considered ideal. For the static structural mechanical analysis, 100 N occlusal load was applied and the bone tissue was fixed. Maximum principal stress showed that the stress pattern was different for the three crown designs, and the traditional bilayer model showed higher stress magnitude comparing to the other models. However, grayscale stress maps showed homogeneous stress distribution for all models. The all-ceramic crown designs affect the stress distribution, and the cutback porcelain-veneered zirconia crown can be a viable alternative to adequate function and esthetic when the monolithic zirconia crown cannot be indicated. Full article

To ensure the long-term success of a dental implant, it is imperative to understand how chewing loads are transferred through the implant prosthetic components to the surrounding bone tissue. The stress distribution depends on several factors, such as load type, bone–implant interface, shape and materials of the fixture and quality and quantity of the bone. These aspects are of fundamental importance to ensure implant stability and to evaluate the remodelling capacity of the bone tissue to adapt to its biomechanical environment. A bone remodelling algorithm was formulated by the authors and implemented by means of finite element simulations on four different implants with several design characteristics. Internal bone microstructure and density, apposition/resorption of tissue and implant stability were evaluated over a period of 12 months, showing the influence of the geometry on bone tissue evolution over time. Bone remodelling algorithms may be a useful aid for clinicians to prevent possible implant failures and define an adequate implant prosthetic rehabilitation for each patient. In this work, for the first time, external bone remodelling was numerically predicted over time. Full article

Prosthesis treatment requires the close interaction of different actors. In fitting prostheses to patients, special attention is given to the manufacturing of the socket. The continuous development of the technologies involved in the fitting and optimization of prostheses is shown in the literature. The assessment of orthopedic technicians and their influence in the process is thus far largely unexplored. Ten orthopedic technicians were interviewed about the socket fitting process after transfemoral amputation. The research goal was to clarify the socket treatment process with regards to the German context. The results showed that the orthopedic technicians focussing on the patient during the fitting process. This study underlines the importance of interaction and empathy. Volume fluctuations are decisive within the treatment process and are interactively influenced by various factors. Furthermore, the research emphasizes the need for appropriate assistive technologies and the potential for the further development of existing systems. Full article

The nature of immediate implant placement followed by an immediate restoration protocol makes it particularly suited to the anterior maxilla. In addition to saving treatment time and avoiding additional surgical procedures, this protocol has been reported to improve aesthetic outcomes by supporting the peri-implant tissues during the implant healing phase through the use of a provisional restoration. This case report documents the use of this protocol in a patient with a failing maxillary anterior tooth and reports on the soft and hard tissue changes over an observation period of 10 years. An implant was immediately placed after removal of a failing maxillary central incisor followed by the provision of a screw retained provisional crown on the same day. A definitive restoration was placed after a 3-month healing period. Not only did this protocol manage to maintain peri-implant bone levels over the 10-year follow-up period, excellent aesthetic outcomes and very limited soft tissue recession were observed with the use of this technique. Full article

The purpose of this survey was to determine removable partial denture (RPD) framework design concepts, new materials, and digital technology that are currently being taught in the predoctoral RPD curriculums in the U.S. dental schools. A questionnaire including RPD framework design concepts, materials, and digital technology was created on Qualtrics. The link to the questionnaire was distributed by email in May 2018 to U.S. dental schools. Thirty-nine of the sixty-six schools responded, yielding a response rate of 59%. Most schools are utilizing textbooks by McCracken and/or Stewart as their primary reference (90%). Only a few schools teach incisal rest (24%) and intra-coronal retainers (8%) in the clinic. The majority of schools teach three or less clasp assembly variations for distal extension RPD scenarios and utilize altered cast impression techniques only for selective patient scenarios. Half of schools currently utilize digital technology in their RPD curriculum. Although twenty-five schools (69%) indicated that implant-assisted RPD (IARPD) is being taught in the curriculum, only nineteen of them teach IARPDs in the clinic. Half of schools are utilizing non-metal clasp denture (NMCD) in their curriculum; most of these school provide this treatment as immediate/interim partials or long-term interim partials. Many U.S. dental schools are simplifying RPD design concepts and principles that are being taught. More schools are introducing new concepts and materials such as IARPD and NMCDs while incorporating digital technology in their predoctoral RPD curriculum. Full article

People who either use an upper limb prosthesis and/or have used services provided by a prosthetic rehabilitation centre, hereafter called users, are yet to benefit from the fast-paced growth in academic knowledge within the field of upper limb prosthetics. Crucially over the past decade, research has acknowledged the limitations of conducting laboratory-based studies for clinical translation. This has led to an increase, albeit rather small, in trials that gather real-world user data. Multi-stakeholder collaboration is critical within such trials, especially between researchers, users, and clinicians, as well as policy makers, charity representatives, and industry specialists. This paper presents a co-creation model that enables researchers to collaborate with multiple stakeholders, including users, throughout the duration of a study. This approach can lead to a transition in defining the roles of stakeholders, such as users, from participants to co-researchers. This presents a scenario whereby the boundaries between research and participation become blurred and ethical considerations may become complex. However, the time and resources that are required to conduct co-creation within academia can lead to greater impact and benefit the people that the research aims to serve. Full article