Platelet-rich plasma for regeneration of neural feedback pathways around dental implants: a concise review and outlook on future possibilities

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Touch and Hearing Mediate Osseoperception

Osseoperception is the sensation arising from the mechanical stimulation of a bone-anchored prosthesis. Here we show that not only touch, but also hearing is involved in this phenomenon. Using mechanical vibrations ranging from 0.1 to 6 kHz, we performed four psychophysical measures (perception threshold, sensation discrimination, frequency discrimination and reaction time) on 12 upper and lower limb amputees and found that subjects: consistently reported perceiving a sound when the stimulus was delivered at frequencies equal to or above 400 Hz; were able to discriminate frequency differences between stimuli delivered at high stimulation frequencies (∼1500 Hz); improved their reaction time for bimodal stimuli (i.e. when both vibration and sound were perceived). Our results demonstrate that osseoperception is a multisensory perception, which can explain the improved environment perception of bone-anchored prosthesis users. This phenomenon might be exploited in novel prosthetic devices to enhance their control, thus ultimately improving the amputees' quality of life

Bridging the gap between robotic technology and health care

Although technology and computation power have become more and more present in our daily lives, we have yet to see the same tendency in robotics applied to health care. In this work we focused on the study of four distinct applications of robotic technology to health care, named Robotic Assisted Surgery, Robotics in Rehabilitation, Prosthetics and Companion Robotic Systems. We identified the main roadblocks that are limiting the progress of such applications by an extensive examination of recent reports. Based on the limitations of the practical use of current robotic technology for health care we proposed a general modularization approach for the conception and implementation of specific robotic devices. The main conclusions of this review are: (i) there is a clear need of the adaptation of robotic technology (closed loop) to the user, so that robotics can be widely accepted and used in the context of heath care; (ii) for all studied robotic technologies cost is still prohibitive and limits their wide use. The reduction of costs influences technology acceptability; thus innovation by using cheaper computer systems and sensors is relevant and should be taken into account in the implementation of robotic systems

Osseointegrated total hip replacement connected to a lower limb prosthesis: a proof-of-concept study with three cases

Background Osseointegrated implants are a suitable alternative for prosthetic attachment in individuals with a transfemoral amputation, who are unable to wear a socket. However, the small bone-implant contact area, reduced muscular leverage, and osteoporosis contraindicate osseointegrated implant use in transfemoral amputees with osteoporosis and a short residuum. We report on the feasibility of combining total hip replacement (THR) with an osseointegrated implant for prosthetic attachment. Methods We retrospectively reviewed the cases of three transfemoral amputees who underwent osseointegration with THR between 2013 and 2014. In a two-stage procedure, a custom-made femoral prosthesis was connected to a THR with a modular revision stem and a stoma was created. Clinical outcomes were assessed at baseline and 1.5–2.5-year follow-up using standard measures of health-related quality of life, ambulation, and activity levels including the Short Form-36 (SF-36), Questionnaire for Transfemoral Amputees (Q-TFA), Timed Up and Go test, and 6-min walk test. Results Patient age ranged from 35 to 65 years. There were no major adverse events, but there was one case of superficial infection. All patients showed improved Q-TFA and SF-36 scores. Two patients who were wheelchair-bound at baseline became community ambulators, and the third patient exhibited improved ambulation. Conclusions This study demonstrated the feasibility of combining a THR with an osseointegrated implant in transfemoral amputees

Investigating interocclusal perception in tactile teeth sensibility using symmetric and asymmetric analysis

The purpose of this clinical trial was to determine the active tactile sensibility of natural teeth and to obtain a statistical analysis method fitting a psychometric function through the observed data points. On 68 complete dentulous test persons (34 males, 34 females, mean age 45.9 ± 16.1years), one pair of healthy natural teeth each was tested: n = 24 anterior teeth and n = 44 posterior teeth. The computer-assisted, randomized measurement was done by having the subjects bite on thin copper foils of different thickness (5-200µm) inserted between the teeth. The threshold of active tactile sensibility was defined by the 50% value of correct answers. Additionally, the gradient of the sensibility curve and the support area (90-10% value) as a description of the shape of the sensibility curve were calculated. For modeling the sensibility curve, symmetric and asymmetric functions were used. The mean sensibility threshold was 14.2 ± 12.1µm. The older the subject, the higher the tactile threshold (r = 0.42, p = 0.0006). The support area was 41.8 ± 43.3µm. The higher the 50% threshold, the smaller the gradient of the curve and the larger the support area. The curves showing the active tactile sensibility of natural teeth demonstrate a tendency towards asymmetry, so that the active tactile sensibility of natural teeth can mathematically best be described by using the asymmetric Weibull functio

Tactile Sensibility Thresholds in Implant Prosthesis, Complete Dentures and Natural Dentition: Review about Their Value in Literature

[EN]Background and Objectives: The periodontium has important proprioceptive receptors that prevent teeth from using excessive occlusal forces during chewing. There are other receptors from adjacent tissues that replace periodontal ones when teeth are extracted and rehabilitated with prosthesis, although they seem to be less effective. Psychophysical studies investigate tactile sensibility thresholds, which are useful to measure this masticatory efficiency in different prosthetic rehabilitations. There are two types of sensibility depending on the receptors that are activated during these studies: active and passive tactile sensibility. The purpose of this study is to obtain active and passive tactile sensibility threshold figures in natural dentition and prosthetic rehabilitations so we can compare them and understand how this sensibility works in different situations. Materials and Methods: We performed a systematic review of the available literature, following PRISMA guidelines and including articles from 2004 to 2021 in the MEDLINE database. Only 10 articles were included in this investigation as they provided concrete threshold figures. Results: The mean values of active tactile sensibility thresholds in complete dentures, implant prosthesis and natural dentition are 64 µ, 23.3 µ and 16.1 µ, respectively. The mean values of passive tactile sensibility thresholds in implant prosthesis and natural dentition are 6.7 N and 0.8 N, respectively. Conclusions: Implant prosthesis have lower thresholds, that are very close to those present in natural dentition, than complete dentures due to an increased tactile sensibility. Active tactile sensibility thresholds present fewer differences between values than passive tactile ones; as these are only influenced by receptors from periodontal or periimplant tissues

Applications of Mechanics and Modelling to Biomechanical Themes

This paper examines the application of mechanics to model the behaviour of the human body. Understanding of this behaviour is necessary in order to improve medical interventions for injury and disease that affect the daily function of an individual. Modelling techniques are presented that enable predictions of how the tissues of the body respond to changes in their mechanical environment. Finite element methods are often used to model both hard and soft tissues and it is important to understand the limitations of these techniques but also their power in predicting responses that may lead to improvements in health care. Examples are presented of modelling plates to fix broken bones, how the next generation of artificial limbs might be attached directly to the skeleton and how osteoporosis affects the strength of the spine