Prosthesis, Volume 5, Issue 2 (June 2023) – 16 articles

People with lower limb amputations struggle through difficulties during locomotion in their daily activities. People with transtibial amputations take support from prosthetic legs for systematic movement. During motion, they experience some mobility issues while using general prosthetic limbs regarding gait pattern. The design of a prosthetic-controlled lower limb with gait synchronization for physically disabled persons is the main goal of the present research work, which can provide an improved walking experience. The design and performance analysis of prosthetic lower limbs for people with transtibial amputations is performed in the present paper. The designed rehabilitation system shows synchronization between the normal and the prosthetic limbs achieved with gait coordination. The dynamics of the lower extremities in different postural activities are used for design purpose utilizing Euler–Lagrange motion theory. The artificial motion of the knee and the ankle joints function through the angular movement of the servo motors according to the movements of the rotary encoders placed on the sound limb joints. The range of motion of both the sound and prosthetic limbs are compared for different steps during a gait cycle. The prosthetic electronic system design of the artificial lower limb is able to show the gait style of human being with body kinesics. The nonlinear domain stability analysis of the designed prosthetic limb is presented through the Lyapunov method. A PIDF2 controller tuning process is implemented for the designed limb’s performance improvement. The designed prosthetic system is beneficial for people with unilateral transtibial amputations with a great societal impact. Full article

Vascular-free flaps are the most frequently employed method in cases of jaws reconstruction after large tumor removal. This therapeutic choice is due to its intrinsic blood supply, which speeds up recovery and enables healing apart from the injured recipient site. This method is most commonly used in secondary reconstructions brought on by radiation, infection, or prior surgical intervention. In fact, with the help of 3d technology, guides can be designed to perform the grafting very smoothly. The purpose of this review with meta-analysis is to compare the two methods: the one using 3d and the freehand one. Methods: In accordance with the entered keywords, a literature search was conducted on PubMed, Lilacs, and Web of Science. Articles published between 2000 and 4 January 2023 were taken into consideration. Using the Boolean connective AND, the terms “jaw reconstruction”, “cad-cam”, and “cancer” have been joined. Results: After searching the three search motors, 148 articles were selected, and only 7 were chosen for this review. Conclusions: The pre-operative morphological position looks to be accurately restored using the CAD/CAM reconstructive methodology. Reconstruction using CAD-CAM and 3d technology allows for greater accuracy, less operative time, and improved aesthetics. Full article

The prevalence of individuals with flat feet and high arches is very high (between 15% to 37%), which can often lead to other orthopedic complications. Three-dimensional-printed insoles are being studied and validated for their effects in correcting these highly prevalent foot disorders. Highly customizable parameters while printing the insole allows for precise correction of foot biomechanics. In this study, 200 patients suffering from various foot-related problems and joint pain were given 3d-printed insoles (designed using plantar pressure systems and clinical practitioner’s assessment) to use in their footwear. Tested activities included standing, walking, running, sports, and gym workout. Customization of insoles included custom density, heel cup, heel rise, medial arch height, and lateral wedge. Based on the patient history, additional podiatry elements were provided for patients with diabetes. Each insole was designed as per the insole profile of the shoe with a comfortable fit. These insoles were found to be effective in alleviating pain for more than 90% of the patients and provided a longer life cycle with effective orthotic correction (for >16 months of daily use). This paper presents the post-use effects (6–18 months) of custom 3D-printed insoles. Full article

Background: Effective debris and smear layer removal affects post-cementation and bond strength. Aim: The aim was to compare the effectiveness of debris and smear layer removal using standard irrigation and activated irrigation with heated EDTA. Moreover, an irrigant activation technique was chosen in the current research, employing the ultrasonic activation of an EDTA solution after being heated directly inside the post space preparation. Materials and Methods: 30 single-rooted human mandibular premolar teeth were used in the current study to test the proposed techniques. First, the teeth were cut to have standardised roots 18 mm in length and prepared endodontically, and then the post space was carried out on all the samples. Then the specimens were randomly distributed into three study groups according to the post space irrigation technique. In detail, the groups were group 1, where a 3D cleaning technique was used; group 2, where the traditional irrigation with EDTA was applied; and group 3, where only saline as an irrigant was used. The third group was considered the control group. Next, the teeth were segmented and analysed via scanning electron microscopy (SEM). The magnification was used to evaluate and score the smear layer and debris. Statistical analysis was undertaken using the classic statistical software package (SPSS, version 28.0; SPSS IBM, Armonk, NY, USA). Then, the data were interpreted with a non-parametric analysis of variance (Kruskal–Wallis ANOVA) among the experiment groups. The significance level was decided as p < 0.05. In addition, statistically significant (p < 0.05) lower mean smear layer and debris scores were found in both the examination groups compared to the control group. Results: group 1 demonstrated better results compared to group 2 in terms of cleaning the dentinal walls. Conclusions: The current research concluded that the EDTA 3D cleaning technique is an effective irrigation technique for clearing debris and smear layers in the post space. Future research, such as on push-out bond strength, should be used to verify this research’s conclusions. Key findings: The use of ultrasonically activated heated EDTA improved the smear layer removal. The use of the 3D cleaning technique resulted in better post space cleaning. Full article

The interface between a dental implant and an abutment is stabilized by two mechanical characteristics: a preload of an abutment screw and the friction between the contact surfaces of the implant and the abutment. These mechanical properties are quantitatively analyzed by using physical and mechanical formulas. The important thing is that such mechanical properties cause various biological phenomena when medical devices are inserted into human bodies. Some mechanical complications in dental implant prostheses are closely associated with biological complications. This literature review explores the mechanical complications of the implant–abutment connection and their biological effects in a titanium dental implant system, which is the system most widely used in dental clinics. Understanding the biomechanics of the implant–abutment connection helps to predict the merits and limits of zirconia dental implants, which have been recently introduced and clinically applied. Full article

Background: The socket shield technique (SST) could address the challenges in immediate implant placement by minimizing post-extraction bone resorption while maintaining soft tissue levels. This study aimed to summarize the available evidence and systematically assess the effectiveness of SST immediate implant placement regarding all outcomes (bone loss, esthetics, implant stability, probing depth, complications, and survival rate). Methods: We searched seven electronic databases through April 2023 to identify randomized clinical trials that assessed the effect of immediate implant placed with SST (test group) versus other implant placement protocols without SST. The risk of bias was assessed using Cochrane’s randomized trial quality assessment Tool (RoB 2.0). Random-effects meta-analysis was conducted, with mean difference and 95% confidence intervals (MD, 95% CI) as effect estimates. We used the GRADE approach to assess the certainty of evidence. Results: Twelve RCTs, involving 414 immediate implants, placed in 398 patients, were included. Meta-analyses revealed that the immediate implants placed with SST had a statistically significant decrease in horizontal (MD = −0.28, 95% CI [−0.37, −0.19], p < 0.0001), vertical (MD = −0.85, 95% CI [−1.12, −0.58], p < 0.0001), and crestal (MD = −0.35, 95% CI [−0.56, −0.13], p = 0.002) bone loss, as well as probing depth (MD = −0.64, 95% CI [−0.99, −0.29], p = 0.0003). Additionally, SST had a significant increase in implant stability (MD = 3.46, 95 % CI [1.22, 5.69], p = 0.002) and pink esthetic score (MD = 1.60, 95% CI [0.90, 2.30], p < 0.0001). Only two studies reported shield exposure incidences in the SST group; however, all studies revealed no implant failure and a 100% survival rate. The evidence certainty was assessed as very low. Conclusions: Based on limited evidence, SST was more effective in minimizing bone resorption and improving implant stability and esthetic outcomes than conventional immediate implant placement. Still, SST could not be recommended as a routine clinical protocol due to the lack of a standardized surgical approach; thus, further high-quality RCTs are required to support this conclusion. Full article

Today, older adults are routinely classified into different categories based on their degrees of independence. However, due to the extreme heterogeneity of this group, and the fact that ageing is a progressive process, older adults may require customized prosthetic treatment. Older people, during ageing, may quickly pass into a frail condition, with loss of independence and of the manual skills necessary for proper hygiene maintenance. With this in mind, complete arch rehabilitations can make an important contribution to a patient’s quality of life. New treatment strategies are needed which take into account the priorities of ageing. The aim of this case report is to show an adaptable prosthetic treatment protocol that is useful for older adults. This protocol provides individual satisfaction and also aids forecasting of the patient’s future functional and maintenance needs. Full article

Meshes, especially titanium ones, are being widely applied in oral surgery. In guided bone regeneration (GBR) procedures, their use is often paired with membranes, being resorbable or non-resorbable. However, they present some limitations, such as difficulty in the treatment of severe bone defects, alongside frequent mesh exposure. Customized meshes, produced by a full-digital process, have been recently introduced in GBR procedures. Therefore, the focus of the present review is to describe the main findings in recent years of clinical trials regarding patient-specific mesh produced by CAD/CAM and 3D printing workflow, made in titanium or even PEEK, applied to GBR surgeries. The purpose is to analyze their clinical management, advantages, and complications. This scoping review considered randomized clinical trials, observational studies, cohort studies, and case series/case reports studies. Studies that did not meet inclusion criteria were excluded. The preferred reporting items for scoping reviews (PRISMA-ScR) consensus was followed. A total of 15 studies were selected for this review. Based on the studies included, the literature suggests that meshes produced by a digital process are used to restore complex and severe bone defects. Moreover, they give satisfactory aesthetic results and fit the defects, counteracting grid exposure. However, more clinical trials should be conducted to evaluate long-term results, the rate of complications, and new materials for mesh manufacturing. Full article

People with mid-cervical spinal cord injury (SCI) often have difficulty in performing activities of daily living due to weakness or paralysis in the flexor muscles. The inability to perform activities requiring fine motor control, such as eating, brushing, writing, unlocking doors, etc., affects overall quality of life negatively. To perform such tasks, appropriate movement of the hands, specifically at the wrist, is essential. For SCI patients, wrist orthotics are considered a viable option with which to perform general tasks. Wrist orthotics, used for rehabilitating people with SCI, help to maintain proper wrist and hand positioning; however, patients must frequently change these orthotic devices as per separate activity requirements. This becomes difficult and cumbersome for such patients. In this work, a passive 3D-printed upper-extremity dynamic orthosis was developed to assist SCI patients in their activities of daily living. The orthosis works on the principle of a worm-gear-based mechanism to produce pronation/supination motions at the wrist. To test the developed multipurpose customized orthosis, ten patients with cervical SCI were recruited and prescribed the 3D-printed splint for a period of four weeks. It was assessed through the QUEST questionnaire and a task completion assessment for its performance. The developed multipurpose customized orthotic device was found to provide an appropriate range of motion, ease in performing tasks, and took less time to complete tasks compared to previous works. The results indicated satisfactory performance, thereby improving quality of life. The multipurpose customized orthotic device successfully assisted the subjects with their daily activities, thus making them more independent in their rehabilitative period. Full article

Intent sensing is a growing field within medical device control, with major potential applications for assistive devices, such as prosthetics. As many sensors as possible should be utilised to maximise accuracy. The availability of sensors may change over time due to changing surroundings or activities, sensors failing, and electrode contact being lost. The sensor network should be dynamic and modular in nature, continuing to function even when some sensors are unavailable. The management of sensor unavailability may help to reduce the need for device maintenance, particularly in developing nations with limited availability of these services. An algorithm is proposed to classify intent using networked sensors in real time. Data are gathered using human participants wearing four surface electromyography sensors and performing a pseudo-random sequence of grasps. The relationship between time offset and prediction accuracy is investigated, with the algorithm predicting future intent actions up to half a second in advance. Sensor dropout is simulated by randomly replacing sensor readings with recorded noise. The new algorithm is compared to existing algorithms and shown to be more accurate in situations of sensor dropout, with the difference increasing as more sensors become unavailable. This suggests that when reductions in sensing capabilities are likely to occur over time, the modular method is more appropriate for control. Full article

Implant abutment selection is an important step in implant treatment to restore one or more lost teeth. The aim of this study was to compare stock and individual CAD/CAM full-form abutments after one year in function. A total of 64 subjects with one missing tooth were divided into two groups according to the type of abutment: 34 patients were given a stock abutment, and 30 an individual CAD/CAM abutment. Patients were scheduled for check-ups seven days after functional loading and after four, eight, and twelve months. Peri-implant soft tissue status was checked at every check-up by monitoring parameters traditionally used in similar studies: plaque index; bleeding on probing; and probing depth. To assess the stability of the bone tissue, radiological methods of measuring the amount of bone level compared to the implant shoulder were used. When needed, data were analysed by χ² test or by Fisher’s exact test. The normality of the distribution of quantitative measurements (properties) was tested by the Shapiro–Wilk test. Differences in the distribution of quantitative variables frequencies were analysed by Student’s t-test. Student’s t-test was used for repeated measurements, Mann–Whitney’s U test and ANOVA test for repeated measurements, and Friedmann’s two-way analysis of variance for repeated measurements. The predictive values of the chosen variables on the ABI index were assessed by the logistic regression model (Enter method). The results of this study showed that the impact of the abutment type (individual CAD/CAM or stock) on the average bleeding on probing was significant, especially after eight or twelve months. However, the abutment type did not show a significant correlation with the total crestal bone loss. The level of oral hygiene showed a significant correlation with the average bleeding on probing. The influence of smoking cigarettes on the total crestal bone loss evaluation was also significant. Overall, from a clinical perspective, custom CAD/CAM abutment performed slightly better than stock abutments during the one-year follow-up. Full article

In full-arch rehabilitation with implant-supported fixed prostheses, using monolithic zirconia seems to have several advantages regarding function and esthetics. However, the current scientific evidence is still limited. Thus, the aim of this investigation was to systematically review the literature on monolithic zirconia restorations for full-arch rehabilitation, particularly pursuing the survival rate and mechanical and biological complications. This study’s protocol was registered in PROSPERO (CRD42022301799). The primary literature search was performed in PubMed/MedLine and Web of Science, and a manual search was performed (checking cross-references). The focused question was, “In an adult population with one or both edentulous arches (P), the oral rehabilitation with implant-supported fixed-monolithic zirconia (full arch) (I), compared with oral rehabilitation using fixed-metal-ceramic prosthesis on implants (C), did show superior clinical results (O) in a minimum follow-up of 1 year (T)?” Inclusion and exclusion criteria were defined. Joana Briggs Institute tools were used to evaluate the quality of the studies. Meta-analysis was performed for the variable survival rate (%), applying the specific continuous moderator (follow-up). Data heterogeneity (I²) was assessed. From the initial search, 327 references were obtained. After eliminating duplicates and applying the inclusion/exclusion criteria by reading the titles, abstracts, and full text, seven articles were included. All included articles were observational longitudinal retrospective studies, with a number of prostheses between 7 and 2039. The mean age was 60 years, and the mean follow-up was 49.7 months. They had mandibular, maxillary, or bimaxillary rehabilitations, always with screw-retained retention, with an average survival rate of 97.23%. The number of implants ranged between four and eight. The quality of the articles was over 70%, and the heterogeneity was considered low (I² = 28.64%). Within a mean follow-up of around four years, full-arch implant-supported monolithic zirconia rehabilitations had a high survival rate and minimal complications. Full article

Background: Immediate implant placement (IIP) or Type I implants have become more attractive than conventional implant placements as it reduces the number of surgical procedures and allows faster delivery of the final restoration compared to conventional implant placements. However, the survival of Type I implants varies depending on multiple factors. Purpose: To evaluate the survival rate of Type I implants, and to describe the factors influencing their failure. Materials and methods: A developed search strategy was applied to identify randomised controlled trials on single-unit immediate implants including at least six human participants with a minimum follow-up time of 12 months and published between 1 January 1999 and 1 January 2020 in several databases. The data were extracted independently using validated data extraction forms. Information on survival rates, number of implants placed, loading protocols, setting of the study, location of implants in the jaw, antibiotic protocol, grafting methods, and implant geometry were obtained and assessed. Results: Twenty-six randomised controlled trials with an average follow-up time of 24 months (range = 12–120 months) were included and analysed to give a survival rate ranging between 83.7 and 100%. Fifteen studies reported implant failures, of which twelve reported early losses (loss before definitive restoration). Nine early losses were due to lack of osseointegration, two did not report the reason for implant failure, and one was reported as iatrogenic. Of the eleven studies with 100% survival rates, the common trend observed was the use of titanium implants and an antibiotic regimen using amoxicillin. Conclusions: The survival rate for immediate single implant placement ranged from 83.7 to 100%. Implant failure was not consistently reported and when reported, failure due to lack of osseointegration prior to placement of the definitive restoration was the most common descriptor. Other attributed reasons included infection abscess, mobility after immediate loading, and iatrogenic complications. Full article

The biological factors of dental implants have a significant impact on long-term prognosis. In the cement-retained type or screw cement-retained type prosthesis (SCRP) implants, dental luting cement is used between the abutment and the implant fixture. Residual excess cement remaining around the implant and gingiva is one of the major causes of peri-implantitis, which is the most common cause of late implant failure. The TDP implant prosthetic system is a new cementless screw-retained type prosthetic system, which overcomes the limitations of the conventional implant prosthetic systems. Using this system, not only serves to prevent peri-implantitis caused by residual excess cement, but also the risk of screw loosening and fracture is reduced due to the stress distribution through the substructure (link), which is connected to the zirconia crown via frictional force. In this case report, two patients with tooth defects visited our dental hospital for implant treatment. Both patients were treated using the TDP implant prosthetic system. As a result, functional and esthetically excellent implant prostheses were fabricated and delivered to the patients. On the 3-year follow-up examination, both patients showed successful results, respectively. Full article

This article aims to describe Vertical Edgeless Preparation (VEP), a full-crown vertical preparation technique initially introduced by the Porta Mascarella Group in the 1980s. The method is defined as “periodontally driven” because its main indication is teeth with a loss of periodontal attachment, and it aims to obtain healthier periodontal tissues. This work describes the step-by-step procedure for performing this prosthetic technique and its indications, contraindications, impression phases, temporary crown management, and its biological concept of periodontal dominance. Full article

Humans are said to have habitual and non-habitual chewing sides; however, the functional differences between the chewing sides of implant-supported denture wearers have not been sufficiently clarified. This study aimed to clarify the presence or absence of functional differences between the chewing sides in implant-supported denture wearers. Forty-five patients with bilateral posterior implants were included in this study. The participants were asked to chew a gummy jelly on one side, and the masticatory movement was recorded using a Motion Visi-trainer (MVT V1). For 10 cycles from the fifth cycle after the start of mastication, the pattern of the movement path, the opening distance, the masticatory width, and the cycle time were calculated as parameters of masticatory movement. The amount of glucose eluted during the chewing of gummy jelly was measured and used as a parameter of masticatory performance. Each parameter representing masticatory movement and masticatory performance was compared between the right and left chewing sides and between the habitual and non-habitual chewing sides using a chi-squared test or a paired t-test. There was no difference in the frequency of masticatory path patterns between the right and left chewing sides. Most participants had a normal pattern on the habitual chewing side; however, abnormal patterns were also observed on the non-habitual chewing side. When comparing right and left chewing, no significant difference was observed between chewing sides in terms of opening distance, masticatory width, cycle time, or amount of glucose eluted (p > 0.05). When comparing the habitual and non-habitual chewing sides, masticatory movement on the habitual chewing side showed a larger opening distance (p < 0.001) and masticatory width (p = 0.008), shorter cycle time (p = 0.004), and higher masticatory performance (p < 0.001). It was suggested that there is a functional difference between the habitual and non-habitual chewing sides in the masticatory movement and masticatory performance of implant-supported denture wearers. Full article