Nieves Saiz-Sapena

Unmodified Ti6Al4V can osseointegrate, but sometimes this capacity needs to be improved. This study aimed to see how much porosity improves osseointegration in a Ti6Al4V implant. Three types of Ti6Al4V cylindrical-shaped implants (13.00 mm length × 5.00 mm diameter) were evaluated: solid sandblasted acid-etched, sintered, and porous 3D-printed (681.00 µm average pore size). Fifteen 20-week-old nullipara female parasite-free New Zealand California white rabbits were used, employing the femoral condyle defect model and undertaking µ-CT analysis and pull-out testing eight weeks later. On µ-CT densitometric analysis, the solid sandblasted rod showed the highest new bone growth around the implant. Bone growth was higher inside the implants for the porous 3D-printed (54.00 ± 5.00 mm³) than for the sintered (1.00 ± 0.05 mm³) and zero for the sandblasted implants. In the pull-out test, there were no statistically significant differences in the ANOVA analysis between the sintered (900.00 N ± 310.00 N) and porous 3D-printed (700.00 N ± 220.00 N) implants. Such differences did exist between the sandblasted material (220.00 N ± 50.00 N) and the two other materials (sintered p 0.002, porous p 0.034). The porous 3D-printed and sintered implant pull-out strength were significantly better than that of the solid rod sandblasted implant. Still, there were no statistically significant differences between the first two.

Primary dental implant stability is critical to enable osseointegration. We assessed the primary stability of our newly designed dental implant. We used the calf rib bone animal model. Our implant has an outside tapered screw with two inside barrettes that deploy with a second screw situated at the implant’s crown. We used ten calf ribs with III/IV bone density and inserted ten implants per rib. We deployed the barrettes in the calf rib’s transversal direction to support against the nearby cortical bone. We measured the primary implant’s stability with resonance frequency analysis and collected the Implant Stability Quota (ISQ) in the transverse and longitudinal calf rib planes before (PRE) and after (POS) deploying the barrette. The mean ISQ was PRE 84.00 ± 3.56 and POS 84.73 ± 4.53 (p = 0.84) in the longitudinal plane and PRE 81.80 ± 2.74 and POS 83.53 ± 4.53 (0.27) in the transverse plane. The barrettes’ insertion increases our dental implant primary stability by 11% in the transverse plane and 2% in the longitudinal plane. Our dental implant ISQ values are in the higher range than those reported in the literature and reflect high primary stability after insertion. The barrette deployment improves the dental implant’s primary stability, particularly in the direction in which it deploys (transverse plane).

New subperiosteal dental implants were designed to offer new options to edentulous patients with severe bone resorption for whom endosseous dental implants are not advisable. In our study, we aimed to design and manufacture subperiosteal dental implants with a minimum volume to facilitate surgical maneuvers and metal coverage by mucosa while ensuring maximal long-term implant strength and functionality. With cone-beam CT-scan data obtained from an edentulous patient, a maxilla and mandible recreation were created, and subperiosteal implants were designed and analyzed with FEA (250 MPa infinite-life limit stress). We redesigned them until they stood the infinite-life limit loads mentioned above. Then, they were manufactured with Ti6Al4V alloy and laser-powder bed fusion technology. All implants withstood mechanical tests (450 N static and 150 N loads for five-million cycle 150 N fatigue tests) with no failures. The first design resulted in maxillary and mandibular implant failures. Through the redesign process, the implant volume was reduced, and the number and placement of bone fixation screws were optimized while maintaining resistance to chewing. Once manufactured, these new implants withstood the loads mentioned above without failure. Our subperiosteal dental implants are an option for edentulous patients with severe maxilla and mandibular bone resorption. Manufactured with Ti6Al4V alloy and laser-powder bed fusion technology, they withstood the above-mentioned mechanical tests without failure.

Background context. Dental implants are designed to replace a missing tooth. Implant stability is vital to achieving osseointegration and successful implantation. Although there are many implants available on the market, there is room for improvement. Purpose. We describe a new dental implant with improved primary stability features. Study design. Lab bench test studies. Methods. We evaluated the new implant using static and flexion–compression fatigue tests with compression loads, 35 Ncm tightening torque, displacement control, 0.01 mm/s actuator movement speed, and 9–10 Hz load application frequency, obtaining a cyclic load diagram. We applied variable cyclic loadings of predetermined amplitude and recorded the number of cycles until failure. The test ended with implant failure (breakage or permanent deformation) or reaching five million cycles for each load. Results. Mean stiffness was 1151.13 ± 133.62 SD N/mm, mean elastic limit force 463.94 ± 75.03 SD N, and displacement 0.52 ± 0.04 SD mm, at failure force 663.21 ± 54.23 SD N and displacement 1.56 ± 0.18 SD mm, fatigue load limit 132.6 ± 10.4 N, and maximum bending moment 729.3 ± 69.43 mm/N. Conclusions. The implant fatigue limit is satisfactory for incisor and canine teeth and between the values for premolars and molars for healthy patients. The system exceeds five million cycles when subjected to a 132.60 N load, ensuring long-lasting life against loads below the fatigue limit.

Study Design. We selected the materials and implant design and performed Finite Element Analysis (FEA) studies. Background. Nucleus disc replacements, implanted since 1960, have undergone continuous evolution in materials and designs, but subsidence, extrusion, and in vivo degradation limit widespread use. Aim. The aim of this study is to create a new nucleus disc replacement that avoids the abovementioned drawbacks. Material and Methods. We created eighteen designs with varied materials and analyzed them with FEA in compression and shear tests in a lumbar spine model programmed in Ansys Parametric Design Language. Results. Bionate 80A had the closest mechanical characteristics to the intact disc nucleus. Monobloc designs bore physiological stresses correctly but suffered significant deformations with permanent damage during surgical insertion through the annulus opening. In addition, sandwich designs were too rigid and had an unreliable curing process. Therefore, we chose an oval doughnut-like 5mm wall monobloc Bionate 80A nucleus replacement. It minimized implant stress in loading, distributed loads uniformly, and tolerated lateral compression during implantation. Conclusions. Out of the eighteen designs we analyzed with FEA, we found that the monobloc oval doughnut-like Bionate 80A nucleus replacement reproduced best the biomechanics of the natural disc nucleus and had the lowest subsidence risk as it transmits the load to the ring apophysis. Furthermore, implanting it through the annulotomy required to perform a lumbar microdiscectomy should be possible due to its elasticity. Furthermore, due to its elasticity implanting it through the average annulotomy required to perform a lumbar microdiscectomy should be possible.

Open access peer-reviewed chapter

Chronic pain is a pathological condition that requests specific medical attention. Its treatment has been imperative since the origin of our species, taking advantage of herbs and natural remedies available in the primitive environment. Morphine has stood the test of time as has been continuously used for the past 8 millennia. The anatomical knowledge of the nociceptive sensation pathways led to the introduction of some surgical techniques directed to stop this pain transmission. Due to their aggressiveness and to the fact that they are irreversible, these techniques were soon replaced by neurostimulation procedures. Being reversible and allowing a change in stimulation parameters soon became the preferred treatment strategy. Over the years a small subset of patients continues to suffer from chronic pain refractory to the usual neurostimulation and pain-controlling medications. These patients can perhaps benefit from one of the surgical ablative procedures. Some of these techniques have been proven particularly effective throughout the years. For some limited income patients in underdeveloped countries, these techniques may be their only accessible option. Doctors have to keep in mind these surgical techniques to put them at the service of our patients in the very few cases in which they are needed. Letting these ablative techniques to die in oblivion would be a disservice to our patients.

With an aging population, chronic osteoarthritic hip joint pain is becoming a major issue. Most patients with hip pain can control their pain with conservative measures but with a gradual reduction in their quality of life. When gradually reduced ambulation and pain become recalcitrant, total hip arthroplasty is the next step. For most patients, this is a good way to improve pain control and to recover some quality of life, but for a few this aggressive surgical procedure is not possible. Sometimes co-morbidities make total hip arthroplasties undesirable. At other times, the age of the patients recommends to wait for a while. In these cases, other options have to be explored. Percutaneous partial hip joint sensory denervation has become a notable option as it can provide acceptable rates of pain relief with minimal surgical aggressiveness. There are three modalities to perform it: thermal, cooled and pulsed radiofrequency.

Lateral epicondylitis is a painful condition that impairs the quality of life and the working capacities of many middle-aged people. Conservative treatments offer an opportunity for improvement in the majority of cases. Surgical alternatives can be considered in those patients with persisting pain. Open, arthroscopic and percutaneous extensor tendon procedures offer similar results with 10–20% failure rates. Radiofrequency microtenotomies have been introduced with comparable results to traditional surgical procedures. Although both thermal and pulsed radiofrequency techniques have been applied, there is more experience with the thermal. In the past, thermal radiofrequency has been applied through a 3–5 cm skin incision, but now some researchers have reported its percutaneous application with radiofrequency cannulas. The results are similar to former techniques but with significantly reduced surgical aggressiveness that correlates with less postoperative discomfort and a faster recovery.