Large Number Of Implants Research Articles

Mandibular Flexure and Crestal Bone Stress Distribution on an Implant-Supported Fixed Full Arch Mandibular Prosthesis: Finite Element Analysis in Three Dimensions.

Aim This study's objective was to assess and analyze, using 3D Finite Element Analysis, the impact of four mandibular complete arch superstructures on the distribution of stress in the crestal bone during mandibular flexure. Materials and methods Four Finite element models of the mandible with different implant-retained framework designs have been developed. Three of these models had six axial implants placed at intervals of 11.8 mm, 18.8 mm and 25.8 mm from the midline, respectively. One model had two tilted implants and four axial implants splinted with a single piece of framework at intervals of 8.4 mm, 13.4 mm and 18.4 mm from the midline. For analyzing the stress distribution, the finished product was transferred to ANSYS R 18.1 software(Sirsa, Haryana, India) for finite element simulation, the models were constructed, the ends were restrained, and bilateral vertical loads of 50N, 100Nand 150N were applied to the distal part of the framework. Results Bilateral loads were applied to each of the four 3D FEMand after assessment of Von Mises Stress and Total Deformation, a finding was made that the model with six axial implants supported by a single piece of framework underwent the highest total deformation and the model with four axial implants and two implants with distal tilts displayed most significant Von Mises stress. Conclusion Within the constraints of this 3D FEA, it was determined that mandibular flexure and peri-implant bone stress were affected by the way the framework is divided and the nature of mandibular movement. The three types of frames with the least bone stress are demonstrated by the mandibular deformation that results from two-piece frameworks on axial implants. Regardless of the number of implants, the singleframework splinted with six implantsshows aflexure inmandiblewith the highest bone stress around the implant irrespective of the angulation of the implant. Clinical significance When it comes to edentulous jaws, reducing stress in implant-supported restorative systems at varying degrees of the bone and implant interfaces and superstructures of prosthetics is one of the fundamental goals of implant treatment. A framework with proper design and a low modulus of elasticity reduces mechanical risk. Additionally, a larger number of implants helps to prevent cantilevers and spacing between the implants.

Clinically Based Classification and Positioning Indication for Single-Piece Compressive Implants Placement in Regard to Extraction Socket.

(1) Background: Dental implantology has been rapidly developing over the last decades. The introduction of new materials, surface modifications and implant designs has brought the need to rethink and systematize our knowledge regarding dental implants. Thus, the aim of this paper is to introduce a new classification and implant positioning indications that can be used to maximize the survival rate and the aesthetic outcome of single-piece compressive screw implants. (2) Materials and methods: This classification was based on a multicenter clinical and radiological observation of 151 patients, in whom 1057 implants were placed with a success rate of 98.5% (1041). The follow-up period was up to 82 months with a mean of 22.34 months. (3) Results: it seems that, in the case of single-piece implants, diameter and length of the implant have influence on their survival rate, whereas smoking and hypertension do not. (4) Conclusions: this paper provides clinicians with comprehensive information about the rationale, criteria and implementation of the new classifications based on a large number of implants and long-term observations.

Aspiring to a Future of Near-Zero Dental Implant Complications.

Dental implant demand is expected to grow at an annual rate of 11% between now and 2028. The market is expected to be valued at $8 billion by then. Patients want teeth that are stable, efficient, and esthetically pleasing. If their natural teeth do not meet those desires, then many will make the investment in dental implants. The majority of implant cases will meet, or exceed, the patient's expectations. However, just as multiple local and systemic risk factors can decrease the probability for survival of natural teeth, those same risk factors will be present for dental implants and jeopardize their long-term success.Along with a large number of implants being placed, the future will also bring complications. Dental implant complications will include technical, mechanical, and biological issues.1 Technical and mechanical complications include abutment screw loosening, fracture of the overdenture prostheses, activation of retentive clips, ceramic chipping, fractures, etc. Biological complications include peri-implant mucositis, mucosal enlargement, peri-implantitis (bone loss), pain, inflammation, possible implant loss, and more.2 Undoubtedly, every implant dentist reading this editorial can relate to all of these complications. Simonis et al,3 found that on follow-up of implants ≤16 years, there was a cumulative survival rate of 82.94% and a cumulative complication rate of 48.03% (biological 16.94%, technical 31.09%). The majority of implant losses and biological complications were concentrated in a small group of patients. Technical/mechanical complications were spread out over a larger number of patients. Consequently, there were many successes with a smaller number of patients experiencing most of the complications. This translates to considerable additional chairside time being spent on nearly half of the cases after placement. This is a mutual problem for both patients and clinicians.Currently, complications are a widespread problem as witnessed by the large number of complication-related articles in peer-reviewed journals. A PubMed search on all dental journals between January 1, 2019 and April 23, 2021 revealed that there are 1176 articles published on the topic of dental complications. In that same time-period, JOI published many implant complication-related articles that include peri-implantitis; intraoperative, systemic medication effects; sinus surgery; genetic effects; all-4-screw prosthesis; prosthetic; plus others.4–12Patients and clinicians would both benefit if the implantologist could take the complication rate from 48% to near zero. Medical comorbidities and perioperative risks for patients will become increasingly complex as patients live longer. Our colleagues in orthopedics are making collaborative efforts to decrease surgical orthopedic complication rates. Steps being taken by orthopedists include prudent presurgical assessments regarding indications, risks, and benefits. They have concluded that an organized, systematic, coordinated, multidisciplinary approach to the perioperative management of patients have resulted in decreased complications.13Implant dentistry's complication rate will diminish if researchers, manufacturers, and clinicians work together to discover evidence-based solutions. Clinicians should focus on (i) prevention that includes thorough diagnoses and treatment planning, (ii) precise placement/restoration techniques, and (iii) early detection with proper treatment of complications. Patients also have a responsibility in this near-zero complication goal by practicing state-of-the-art daily oral hygiene with proper diet considerations.

Outcome and complications of distal tibia fractures treated with intramedullary nails versus minimally invasive plate osteosynthesis and the role of fibula fixation.

Distal tibia fractures have been managed conservatively as well surgically. A large number of implants have been used for surgical management of these fractures. No treatment method or implant has been proven to be superior to others. In this prospective comparative study, the complications and outcome of distal tibia fractures managed with intramedullary nails and minimally invasive plate osteosynthesis has been compared. Further, the role of fibula fixation in these fractures has been evaluated. One hundred and fifty-four patients of distal tibia fractures with concomitant fibula fractures were randomized into 4 treatment groups based on predetermined inclusion criteria. Functional outcome in these groups was compared based on AOFAS score at 1year. Intra-operative, post-operative parameters as well as radiological alignment, complications and the need for reoperation were also compared in these groups. The functional outcome in all four treatment groups was similar. The duration of surgery and radiation exposure was higher with minimally invasive plate osteosynthesis. There was no improvement in outcome with plating of fibula. However, fixation of fibula improved the rotational alignment in distal tibia fractures. Although there is no difference in outcome of distal tibia fractures with either nailing or minimally invasive plating, nailing is recommended for closed displaced extraarticular fractures. Fixation of fibula should not be done routinely but should be reserved only for a few specific fracture patterns.

Success rate of short dental implants supporting single crowns and fixed bridges.

Bone grafts (sinus lift and/or ridge augmentation) may become an obstacle for some patients who desire implant treatment. The objective of this study was to evaluate the success of six- and eight-millimeters rough surface design short dental implants, for up to 2years in function, when compared to conventional length (11mm) implants. A total of 25.6-, 20.8- and 35.11-mm length implants were placed and restored in 30 subjects (11 males, 19 females) between the age of 22 and 80, following a standard protocol. Implant mobility, crestal bone loss as well as periodontal parameters were evaluated immediately after restoration placement, at 6, 12 and 24months. There was one failure of one 6-mm implant during the healing phase and one restorative failure. The median crestal bone loss at 24months was 0.45mm for the 6-mm implants, 0.55mm for the 8mm implants and 0.65mm for the 11-mm implants. The success rate for 6-mm implants was 97% and for 8-mm and 11-mm implants 100%. Based on this preliminary data, we conclude that rough surface design short dental implants (6 and 8mm in length) have similar success rate when compared to 11-mm implants. Long-term data with larger number of implants and subjects are needed to confirm these results.

Nailing intertrochanteric hip fractures: short versus long; locked versus nonlocked.

A large number of implants have been developed for intramedullary fixation of intertrochanteric fractures. This article attempts to summarize the contemporary understanding of the existing biomechanical and clinical evidence on intramedullary nailing of intertrochanteric fractures, as to whether they should be short or long nails, and the use or not of distal locking screws. Difficulties on the translation of biomechanical findings to the clinical setting, as well as the pressing demand for standardization of the indications and the use of different modes of cephalomedullary nailing, should direct orthopaedic trauma research toward focused, well-designed clinical studies. Level V-expert opinion.

Periodontal considerations in older individuals.

In the next few years there will be a great increase in the percentage of the population aged over 65. Not only will they have more teeth than previous generations, but also a large number of implants. The increase in age is accompanied by an increase in the prevalence and incidence of periodontal diseases. In addition, there is a decrease in manual dexterity and an increase in co-morbidity and medications affecting the oral cavity. Dental care in aged care facilities can be poor and access to dental professionals difficult. This article discusses these issues.

56th Annual Meeting of the American Academy of Implant Dentistry and the World Congress of Oral Implantology 7 Abstracts, 2007

56th Annual Meeting of the American Academy of Implant Dentistry and the World Congress of Oral Implantology 7 Abstracts, 2007

Endoprothetik des Fingergrundgelenks

Only a few of the large number of implants developed during the last decades for replacement of the metacarpophalangeal (MCP) joint have proven to be reliable. The rates of loosening and mechanical failure of almost all types of constrained prostheses are so high that their use cannot be recommended at present. For more than 40 years silicone arthroplasty according to Swanson has been regarded as the gold standard in the prosthetic replacement of the MCP joint. In long-term studies this device provided good pain relief and a lasting correction of preoperative ulnar deviation. The degree of patient satisfaction continues to be high after more than 10 years. With the NeuFlex spacer, a modification of the original Swanson implant, a better range of motion and a reduction of wear-related problems is expected. In this study the results of 130 NeuFlex spacers after a mean time of 3.6 years were examined and 82% of the patients were completely pain free. The mobility of the joints improved from 40 degrees preoperatively to 54 degrees after 3.6 years. Radiologically periprosthetic erosions or osteolyses were seen in approximately 15% of implants. A minimal sinking of the stems developed in 24%, a massive one in 6% and 13% of the spacers were broken. Thus the use of the NeuFlex implant resulted in a better range of motion compared to the Swanson spacer, but the problem of radiological appearance remained unchanged. For unlinked prostheses sufficient soft tissue stability is mandatory as well as wear-resistant surface materials. The pyrocarbon prosthesis according to Beckenbaugh is the only implant for which long-term results are available. In a prospective study we evaluated 28 Ascension pyrocarbon prostheses with a mean follow-up of 4 years. Stability was not found to be a problem. Subjective results were satisfactory, the range of motion remained unchanged, however 46% of prosthesis stems exhibited radiolucent seams, 7 prostheses (25%) were rated as loose and 5 of those had to be replaced by a silicone implant. Use of the implant was abandoned, as it was unreliable regarding bony fixation. There are promising concepts in some new prostheses but independent data are still lacking.

A Retrospective 5-Year Follow-Up Study of Two Different Titanium Implant Surfaces Used after Interpositional Bone Grafting for Reconstruction of the Atrophic Edentulous Maxilla

Long-term comparative follow-up studies of dental implants placed in augmented bone are rare. Variations in design and surface roughness have been found to be important for bone integration of implants. However, there is no clinical evidence that such variations lead to an improved clinical outcome. To compare two different implant systems used after interpositional bone grafting of the severely resorbed maxilla with a modified augmentation technique using fibrin glue. Twenty-two consecutive patients presenting with severe maxillary atrophy underwent reconstruction with Le Fort I osteotomies and interpositional bone grafting. Before placement of bone blocks, the floors of the maxillary sinuses were packed with bone chips mixed with a fibrin glue, to stabilize the graft. After 6 months of graft healing, the first 11 consecutive patients received Brånemark System implants with a turned surface (Nobel Biocare AB, Göteborg, Sweden). The following 11 consecutive patients were treated with Astra Tech implants with a blasted titanium surface (Astra Tech AB, Mölndal, Sweden). All patients received fixed prostheses. Marginal bone resorption and donor and recipient site morbidity were evaluated. All patients were clinically and radiographically observed throughout 5 years of functional loading. In the Brånemark group, 11 (13%) of 84 placed implants were lost, compared to 4 (5.5%) of 72 placed implants in the Astra Tech group. The difference was not significant. All patients retained fixed constructions after 5 years of loading. The mean marginal bone loss was 2.3+/-0.8 mm (range, 0-5.0 mm) in the Brånemark group and 2.4+/-1.4 mm (range, 0-7.0 mm) in the Astra Tech group although again no statistical difference was found. A larger number of implants in the Astra Tech group had a marginal bone resorption of>or=3 mm, and implant success in that group was lower than in the Brånemark group (52% vs 70%). In this study, reconstruction of the severely resorbed maxilla with Le Fort I osteotomy, interpositional bone grafting, and delayed placement of dental implants was found to be a predictable long-term procedure. Although more implants with a turned surface were lost during the follow-up period, there were no statistically significant differences between turned and titanium blasted implants.

Causes of the clinical tissue response to polyglycolide and polylactide implants with an emphasis on the knee.

The causes of a clinical tissue response to self-reinforced polyglycolide (SR-PGA) and self-reinforced polylactide (SR-PLLA) implants were studied in the first 2500 polymeric fixations. The incidence was 8.0% in fixations with implants made of SR-PGA (n = 1879) and 0% in SR-PLLA fixations (n = 621). A small number of fixations per site seemed to increase the incidence of a tissue response. In diagnoses involving over 50 fixations, except for ankle fractures, the incidence was 4.2%. The site of fixation influenced the incidence; the lowest incidence was seen for radial head fracture fixation (1.1%). The aromatic dye which has not been used since 1988 in the SR-PGA implant increased the response. A large total implant volume and a large number of implants increased the incidence of a tissue response. In the knee (n = 131), the incidence of a clinical tissue response was 4.3%, with four fluid accumulations and one synovitis of the knee after fixation with SR-PGA implants.

Investigation of hyperthermia-induced dominant lethal mutations in male mice.

The mutagenic potential of hyperthermia was investigated in a random-bred stock of mice to determine if this is one mechanism by which elevated ambient temperature exerts its deleterious effects on mammalian reproduction. Two dominant lethal assays were conducted to measure mutagenicity during the meiotic and post-meiotic stages of spermatogenesis following various periods of heat stress. Indirect evidence for hyperthermia-induced dominant lethality was obtained in the form of increases in the frequencies of preimplantation loss and sterile matings. However, the large number of sterile matings precluded unambiguous statistical analysis of the incidence of early embryonic mortality that would have provided direct evidence of induced dominant lethality. Control data indicated that the stock of mice used in this experiment is an excellent choice for dominant lethal studies because of the large number of implants and the low frequency of embryonic mortality.