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Concept: Per-Ingvar Brånemark

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As a result of major ablative surgery, head and neck oncology patients can be left with significant defects in the orofacial region. The resultant defect raises the need for advanced reconstruction techniques. The reconstruction in this region is aimed at restoring function and facial contour. The use of vascularised free flaps has revolutionised the reconstruction in the head and neck. Advances in reconstruction techniques have resulted in continuous improvement of oral rehabilitation. For example, endosteal implants are being used to restore the masticatory function by the way of prosthetic replacement of the dentition. Implant rehabilitation usually leads to improved facial appearance, function, restoration of speech and mastication. Suitable dental implant placement’s site requires satisfactory width, height and quality of bone. Reconstruction of hard tissue defects therefore will need to be tailored to meet the needs for implant placement.The aim of this feasibility study was to assess the compatibility of five standard commercially available dental implant systems (Biomet 3i, Nobel Biocare, Astra tech, Straumann and Ankylos) for placement into vascularised fibula graft during the reconstruction of oromandibular region.Radiographs (2D) of the lower extremities from 142 patients in the archives of the Department of Radiology in University College London Hospitals (UCLH) were analysed in this study. These radiographs were from 61 females and 81 males. Additionally, 60 unsexed dry fibular bones, 30 right sided, acquired from the collection of the Department of Anatomy, University College London (UCL) were also measured to account for the 3D factor.In the right fibula (dry bone), 90% of the samples measured had a width of 13.1 mm. While in the left fibula (dry bone), 90% of the samples measured had a width of 13.3 mm. Fibulas measured on radiographs had a width of 14.3 mm in 90% of the samples. The length ranges of the dental implants used in this study were: 7-13 mm (Biomet 3i), 10-13 mm (Nobel biocare), 8-13 mm (Astra Tech), 8-12 mm (Straumann ) and 8-11 mm (Ankylos).This study reached a conclusion that the width of fibula is sufficient for placement of most frequently used dental implants for oral rehabilitation after mandibular reconstructive procedures.

Concepts: Implants, Dental implant, Oral and maxillofacial surgery, Osseointegration, Free flap, Per-Ingvar Brånemark, Nobel Biocare, University College London

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AIM: The first aim of the present experiment was to compare bone healing at implants installed in recipient sites prepared with conventional drills or a piezoelectric device. The second aim was to compare implant osseointegration onto surfaces with and without dendrimers coatings. MATERIAL AND METHODS: Six Beagles dogs were used in this study. Five implants with two different surfaces, three with a ZirTi(®) surface (zirconia sand blasted, acid etched), and two with a ZirTi(®) -modified surface with dendrimers of phosphoserine and polylysine were installed in the right side of the mandible. In the most anterior region (P2, P3), two recipient sites were prepared with drills, and one implant ZirTi(®) surface and one coated with dendrimers implants were installed at random. In the posterior region (P4 and M1), three recipient sites were randomly prepared: two sites with a Piezosurgery(®) instrument and one site with drill and two ZirTi(®) surface and one coated with dendrimers implants installed. Three months after the surgery, the animals were sacrificed for histological analysis. RESULTS: No complications occurred during the healing period. Three implants were found not integrated and were excluded from analysis. However, n = 6 was obtained. The distance IS-B at the buccal aspect was 2.2 ± 0.8 and 1.8 ± 0.5 mm, while IS-C was 1.5 ± 0.9 and 1.4 ± 0.6 mm at the Piezosurgery(®) and drill groups, respectively. Similar values were obtained between the dendrimers-coated and ZirTi(®) surface implants. The BIC% values were higher at the drill (72%) compared to the Piezosurgery(®) (67%) sites. The BIC% were also found to be higher at the ZirTi(®) (74%) compared to the dendrimers-coated (65%) implants, the difference being statistically significant. CONCLUSION: This study has revealed that oral implants may osseointegrate equally well irrespective of whether their bed was prepared utilizing conventional drills with abundant cooling or Piezosurgery(®) . Moreover, the surface coating of implants with dendrimers phosphoserine and polylysine did not improve osseointegration.

Concepts: Implants, Coating, Dental implant, Osseointegration, Implant, Piezoelectricity, Coatings, Per-Ingvar Brånemark

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Background: To date, very few experimental studies have addressed the effect of bone drilling technique and sequence on dental implant osseointegration. In this study, we hypothesized that there would be no differences in osseointegration when reducing the number of drills for osteotomy compared to the conventional drilling protocols. Methods: Seventy-two implants (diameter 3.75 mm and diameter 4.2 mm, n=36 for each diameter) were bilaterally placed in the tibia of 18 beagles for 1, 3, and 5 weeks. Half of the implants of each diameter were placed using a simplified drilling procedure (pilot and final drill) and the other half were placed using a conventional drilling procedure (all drills in sequence). The retrieved samples were subjected to histologic/histomorphometric evaluation. Results: Histology showed that new bone formed around the implant and inflammation or bone resorption was not evident for both groups. Histomorphometrically, the simplified group presented significantly higher bone-to-implant contact and bone area fraction occupancy as compared to the conventional group after 1 week, however, no differences were detected at 3 and 5 weeks. Conclusion: It can be suggested that bone responses to the implant with the simplified protocol is comparable to the conventional protocol.

Concepts: Implants, Prosthetics, Drill, Dental implant, Titanium, Oral and maxillofacial surgery, Osseointegration, Per-Ingvar Brånemark

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Background: Concerns have been raised that use of surface-modified implants may result in peri-implant infection and marked marginal bone loss over time. Purpose: The aim of this prospective study was to evaluate the survival rate, marginal bone, and soft tissue conditions at surface-modified titanium dental implants after 10 years of function. Material and Methods: Forty-six totally and partially edentulous patients were provided with 121 Brånemark oxidized implants (TiUnite™, Nobel Biocare AB, Gothenburg, Sweden). Twenty-four (20%) implants were immediate loaded and 97 (80%) were placed using a two-stage procedure. A total of 22 single, 23 partial, and 7 total restorations were delivered. Clinical and radiographic checkups were carried out after 3, 6, 12 months, and thereafter annually up to 10 years. At these occasions, oral hygiene was evaluated and peri-implant mucosa examined by probing. If needed, patients were enrolled in an individual program for hygiene controls and professional cleaning. Marginal bone loss was evaluated in intraoral radiographs taken at baseline and after 1, 5, and 10 years of function. Results: One (0.8%) implant failed after 8 years giving a Survival Rate (SR) of 99.2% after 10 years. A total of 11 sites (9.2%) showed bleeding on probing (BP) at the 10th annual checkup. The mean marginal bone loss was 0.7 ± 1.35 mm based on 106 readable pairs of radiographs from baseline and from the 10th annual examination. Twelve (11.3%) implants showed more than 2 mm bone loss, and five (4.7%) showed more than 3 mm of bone loss after 10 years. For the latter, all patients were smokers and had poor or acceptable oral hygiene. All five implants with >3 mm bone loss showed BP and two (1.9%) showed suppuration from the pocket. For the remaining seven implants with more than 2 mm bone loss, no correlation to smoking, oral hygiene, bleeding, or pus could be seen. Time/marginal bone level plots of the 12 implants with more than 2 mm bone loss after 10 years, showed minor changes from the first annual checkup except for the two infected implants. Conclusions: It is concluded that good long-term clinical outcomes can be obtained with oxidized titanium dental implants. Only 1.9% of examined implants showed significant marginal bone loss together with bleeding and suppuration after 10 years of function.

Concepts: Periodontology, Gingiva, Dental implant, Per-Ingvar Brånemark, Nobel Biocare

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Our previous studies demonstrated that a recombinant fibronectin (FN)-derived oligopeptide that we named F20 stimulated osteoblast adhesion, proliferation, and differentiation in vitro and in vivo. In the present study, we used a synthetic oligopeptide and investigated the osteogenic potential of F20 coating on titanium discs, to stimulate superior osseointegration for dental implant surface modification. Surface characteristic analysis of titanium was performed by confocal laser scanning microscopy (CLSM) observation. Synthetic F20 was coated onto the machined or SLA titanium discs by an adsorption procedure. ST2 cells were seeded on the titanium discs. We evaluated cell adhesion with SEM and CLSM observation, cell proliferation with picogreen assay, and osteoblast differentiation with real-time PCR, ALP activity assay, immunoblot assay and ALP staining. FITC-labeled F20 coating on the discs was detected by fluorescence, showing good F20 adsorption and different coating patterns according to the surface roughness. In the SEM and CLSM observations, cells were well attached on the machined surface and greater stress fiber formation was seen on discs coated with F20 than on other discs. F20 stimulated cellular proliferation, as well as osteoblast differentiation through the extracellular signal-regulated kinase (Erk) signaling pathway. These cellular responses to F20 were slightly better on the machined titanium surface than the SLA surface. These results suggest that F20 promotes osteogenesis through the Erk pathway and is a suitable biomolecule for surface modification of dental implants for improved osseointegration.

Concepts: Signal transduction, Implants, Materials science, Dental implant, Titanium, Oral and maxillofacial surgery, Osseointegration, Per-Ingvar Brånemark

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Antihypertensive drugs in general are beneficial for bone formation and remodeling, and are associated with lower risk of bone fractures. As osseointegration is influenced by bone metabolism, this study aimed to investigate the association between antihypertensive drugs and the survival rate of osseointegrated implants.

Concepts: Bone, Implants, Orthopedic surgery, Dental implant, Titanium, Oral and maxillofacial surgery, Osseointegration, Per-Ingvar Brånemark

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With the increasing popularity of dental implants, the removal of fractured implants has become a major challenge for clinicians. Several tools can be used for the removal of osseointegrated implants; however, few of these have the characteristics of easy control, selective cutting, and rapid healing. In this study, the authors describe a step-by-step technique for the removal of osseointegrated fractured implants via multiple peri-implant osteotomies performed using a piezoelectric device and appropriate inserts. All patients ended with primary wound closure without any soft tissue dehiscence and no healing problems during the postoperative period. As the use of ultrasonic inserts enables precise and selective cuts, piezosurgical implant removal is an attractive alternative to trephine burs or rotary drills.

Concepts: Tissues, Implants, Prosthetics, Drill, Dental implant, Oral and maxillofacial surgery, Osseointegration, Per-Ingvar Brånemark

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A current implant body surface was treated with “rough processing” by sandblasting and acid etching for the purposes of obtaining more reliable osseointegration and shortening the treatment period. Various reports have examined the healing period with the use of these implant bodies, but a consensus opinion has not yet been obtained. The purpose of this study is to evaluate the relationship between insertion torque (IT) and implant stability quotient (ISQ) at implant treatment using the current rough-surfaced implant. We evaluated the implant treatment sites with ISQ values, IT values, and voxel values.

Concepts: Implants, Prosthetics, Dental implant, Dentistry, Osseointegration, Implant stability quotient, Body, Per-Ingvar Brånemark

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Osseointegration is paramount for the longevity of dental implants and is significantly influenced by biomechanical stimuli. The aim of the present study was to assess the micro-strain and displacement induced by loaded dental implants at different stages of osseointegration using finite element analysis (FEA). Computational models of two mandible segments with different trabecular densities were constructed using microCT data. Three different implant loading directions and two osseointegration stages were considered in the stress-strain analysis of the bone-implant assembly. The bony segments were analyzed using two approaches. The first approach was based on Mechanostat strain intervals and the second approach was based on tensile/compression yield strains. The results of this study revealed that bone surrounding dental implants is critically strained in cases when only a partial osseointegration is present and when an implant is loaded by buccolingual forces. In such cases, implants also encounter high stresses. Displacements of partially-osseointegrated implant are significantly larger than those of fully-osseointegrated implants. It can be concluded that the partial osseointegration is a potential risk in terms of implant longevity.

Concepts: Finite element method, Continuum mechanics, Implants, Prosthetics, Dental implant, Partial differential equation, Osseointegration, Per-Ingvar Brånemark

0

Dental implants have become a widely accepted and successful treatment for fully and partially edentulous patients. Simvastatin has been applied to improve and accelerate the osseointegration of implants by increasing the quantity and quality of bone tissue. However, its potential mechanism has not been elucidated completely. Here, we found that simvastatin significantly enhanced the autophagy level of jaw-derived bone marrow stromal cells (BMSCs) and alleviated production of reactive oxygen species under unfavourable conditions. Simvastatin promoted osteogenic differentiation of BMSCs via enhanced autophagy. Furthermore, simvastatin inhibited the bone resorption activity of osteoclasts. With the use of a rat model of oral implant osseointegration, we found local injection of simvastatin displayed more new bone formation at the interface of the bone and implant compared with that of oral administration. Fluorochrome labelling histomorphometrical analysis and micro-CT also showed that simvastatin promoted the osseointegration of implants. Notably, fewer activated osteoclasts were observed in the region of osseointegration of implants from the simvastatin treatment groups, especially the local delivery of simvastatin. Collectively, our results revealed that simvastatin can increase osteoblastic differentiation of BMSCs via enhanced autophagy and decreased osteoclast activity. Thus, simvastatin could be a viable and promising drug to improve and even accelerate the osseointegration of a dental implant.

Concepts: Bone, Implants, Dental implant, Titanium, Oral and maxillofacial surgery, Osseointegration, Per-Ingvar Brånemark, Edentulism