Surface functionalization of chitosan as a coating material for orthopaedic applications: A comprehensive review.

Metallic implants have dominated the biomedical implant industries for the past century for load-bearing applications, while the polymeric implants have shown great promise for tissue engineering applications. The surface properties of such implants are critical as the interaction of implant surfaces, and the body tissues may lead to unfavourable reactions. Desired implant properties are biocompatibility, corrosion resistance, and antibacterial activity. A polymer coating is an efficient and economical way to produce such surfaces. A lot of research has been carried out on chitosan (CS)-modified metallic and polymer scaffolds in the last decade. Different methods such as electrophoretic deposition, sol-gel methods, dip coating and spin coating, electrospinning, etc. have been utilized to produce CS coatings. However, a systematic review of chitosan coatings on scaffolds focussing on widely employed techniques is lacking. This review surveys literature concerning the current status of orthopaedic applications of CS for the purpose of coatings. In this review, the various preparation methods of coating, and the role of the surface functionalities in determining the efficiency of coatings are discussed. Effect of nanoparticle additions on the polymeric interfaces and in regulating the properties of surface coatings are also investigated in detail.

Reflection of an ultrasonic wave on the bone-implant interface: Comparison of two-dimensional and three-dimensional numerical models.

Quantitative ultrasound is used to characterize osseointegration at the bone-implant interface (BII). However, the interaction between an ultrasonic wave and the implant remains poorly understood. Hériveaux, Nguyen, and Haiat [(2018). J. Acoust. Soc. Am. 144, 488-499] recently employed a two-dimensional (2D) model of a rough BII to investigate the sensitivity of the ultrasonic response to osseointegration. The present letter aimed at assessing the validity of the 2D assumption. The values of the reflection coefficient of the BII obtained with two and three-dimensional models were found not to be significantly different for implant roughness lower than 20 µm. 2D modeling is sufficient to describe the interaction between ultrasound and the BII.

3-dimensional visualization of implant-tissue interface with the polyethylene glycol associated solvent system tissue clearing method.

OBJECTIVES: Dental implants are major treatment options for restoring teeth loss. Biological processes at the implant-tissue interface are critical for implant osseointegration. Superior mechanical properties of the implant constitute a major challenge for traditional histological techniques. It is imperative to develop new technique to investigate the implant-tissue interface. MATERIALS AND METHODS: Our laboratory developed the polyethylene glycol (PEG)-associated solvent system (PEGASOS) tissue clearing method. By immersing samples into various chemical substances, bones and teeth could be turned to transparent with intact internal structures and endogenous fluorescence being preserved. We combined the PEGASOS tissue clearing method with transgenic mouse line and other labelling technique to investigate the angiogenesis and osteogenesis processes occurring at the implant-bone interface. RESULTS: Clearing treatment turned tissue highly transparent and implant could be directly visualized without sectioning. Implant, soft/hard tissues and fluorescent labels were simultaneously imaged in decalcified or non-decalcified mouse mandible samples without disturbing their interfaces. Multi-channel 3-dimensional image stacks at high resolution were acquired and quantified. The processes of angiogenesis and osteogenesis surrounding titanium or stainless steel implants were investigated. CONCLUSIONS: Both titanium and stainless steel implants support angiogenesis at comparable levels. Successful osseointegration and calcium precipitation occurred only surrounding titanium, but not stainless steel implants. PEGASOS tissue clearing method provides a novel approach for investigating the interface between implants and hard tissue.

Four Stable and Functioning Dental Implants Retrieved for Fracture After 14 and 17 Years from the Same Patient: A Histologic and Histomorphometric Report.

The aim of the present study was a histologic and histomorphometric analysis of the peri-implant tissue reactions and of the bone-titanium interface in successfully osseointegrated, clinically stable, and immobile retrieved titanium dental implants after a long loading period. Four successfully osseointegrated and stable implants with a sandblasted surface were retrieved from a patient due to fracture, two after 14 years of loading and two after 17 years. None of these implants has been previously reported. Mature, compact bone with a few marrow spaces was observed around all four implants. At low magnification, a high percentage of bone-implant contact (BIC) was present at the interface of almost all implants. BIC percentage for the four implants was 83%, 66%, 74%, and 65%. In almost all the implants, the space within the threads was almost completely filled by compact bone. Close, tight contact between bone and implant surface was observed in all specimens, and no gaps or fibrous connective tissue was found at the bone-implant interface. All implants appeared to be well integrated in the surrounding mineralized bone, and all showed adequate BIC percentages after a long loading history.

La biología de la oseointegración en los implantes postextraccion / The biology of osseointegration in postextraction implants

Los fenómenos biológicos de la oseointegración comprenden un proceso de reabsorción y formación ósea que ha sido descrito en estudios histológicos en animales y humanos. La extracción de dientes seguida de la inserción de implantes inmediatos provoca alteraciones en las dimensiones del hueso alveolar con gaps horizontales y verticales entre las paredes del alveolo y el implante. La reabsorción de la pared vestibular parece ser más pronunciada. Esta deshicencia ósea despues de la inserción de implantes postextracción ha sido corroborada en experimentos con animales y confirmada en studios clínicos con pacientes. Diversos factores pueden afectar a la respuesta biológica de los tejidos periimplantarios y el contacto hueso-implante en los alveolos postextracción como la densidad de hueso, la superficie y el diseño del implante y la técnica quirúrgica. Conclusión: La investigación experimental y clínica indica que la inserción de implantes en alveolos frescos no perjudica la remodelación de los tejidos periimplantarios. Sin embargo, tiene lugar la reabsorción ósea tanto de la pared vestibular como lingual

The biology of osseointegration involve a process of healing with bone resorption and bone apposition, as described histologically in animal and human studies. The removal of teeth followed by immediate implant placement results in marked alterations to alveolar ridge dimensions as well as horizontal and vertical gaps between the bone walls and the implant. Resorption of the buccal plate was seen to be more pronounced; this bone dehiscence following implant placement corroborates findings reported in animal experiments and confirmed in clinical studies with patients. Several factors affecting the biologic response of peri-implant tissues and bone-implant contact in postextraction implants as original bone density, implant surfaces, implant design and surgical technique. Conclusions: Experimental and clinical research studies suggest that the insertion of implant in fresh sockets does not jeopardize remodeling of periimplant tissues. However, bone resorption can be expected on both the lingual and buccal aspects

La oseointegración de implantes de titanio con diferentes superficies rugosas / Osseointegration of titanium implant with several rough surfaces

La superficie de los implantes es muy importante para conseguir la oseointegración. Existen muchos tipos de superficies en los implantes dentales. La investigación en superficie de implantes comienza con la superficie mecanizada. La superficie rugosa incrementa la adherencia celular y muestra una mayor área de contacto hueso-implante. El recubrimiento con plasma de titanio e hidroxiapatita fueron métodos comunes para modificar la rugosidad de la superficie. Más recientemente, el arenado (ej. alúmina) y el grabado ácido (ej. chorhídrico, sulfúrico, nítrico) son otros procesos que pueden incrementar la superficie rugosa de los implantes. Más recientemente, la tecnología ha comenzado en la implantología oral con el desarrollo de superficies porosas que manifiestan una mejor respuesta osteogénica e incrementa la unión mecánica hueso-titanio. La oseointegración parece estar influenciada por los modelos de especies animales. En el conejo el proceso es más rápido que en el perro, y en el perro es más rápido que en el hombre. La incorporación de nuevos materiales y procesos técnicos en la investigación sobre superficies de implantes ofrecen nuevas posibilidades de mejorar su respuesta tisular y su potencial óseo regenerativo. Conclusiones: El tratamiento de la superficie de los implantes constituye un importante campo en futuras investigaciones de la implantología oral mediante los estudios de experimentación

Implant surface is very important for enhance the osseointegration. They are many types of dental implant surfaces. Implant surface research begins with machined surface. Roughened surface titanium increase cell adhesion and exhibit stronger bone-implant contact area. Plasma-spray and hydroxyapatite coating were common methods for rough surface modification. Most recently, blasting (i.e. alumina) and acid-etching (i.e. hydrochloric, sulphuric and nitric) are another process by which surface roughness can be increased. Most recently, technology begins in implant dentistry with the development of porous surfaces that manifest better osteogenic response and increase bone-titanium mechanical interlocking. Osseointegration appeared to be strongly influenced by the animal species model. The rabbit model was faster compared to the dog model, and the dog model was faster the human model. The introduction of new materials and new technical process in dental surfaces research offering new possibilities for better tissue response and bone regenerative potential. Conclusions: The surface modifications of titanium constitute an important field for future research of implant dentistry by experimental studies

Hard and soft tissue changes around implants activated using plasma of argon: A histomorphometric study in dog.

OBJECTIVE: To histologically assess the hard and soft tissue changes after insertion of cleaned and activated titanium implants using plasma of argon. MATERIALS AND METHODS: Eight dogs were included in this study. The mandibular premolars and first molars were extracted. For each hemi-mandible, four implants, 7 mm long and 3.3 mm of diameter, with a ZirTi surface were used. The surface of two implants was randomly treated with argon plasma (test), while the other two implants were left untreated (control). After 1 month, the same procedure was performed in the contralateral hemi-mandible. The amount of old bone, new bone, overall value of old bone plus new bone, and soft tissue was histologically evaluated. RESULTS: After 1 month of healing, high percentages of new bone in close contact with the implant surface were found at both the treated (60.1% ± 15.6%; 95% CI 56.5%-78.0%) and untreated (57.2% ± 13.1%; 95% CI 49.3%-67.5%) implants. Low percentages of old bone were found at this stage of healing, at both the treated (4.4% ± 3.0%; 95% CI 1.2%-5.4%) and untreated (3.4% ± 3.1%; 95% CI 0.6%-4.9%) implants. Not statistically significant differences were found between groups (p > .05). After 2 months of healing, treated implants presented a significantly higher (p = .012) new bone formation (72.5% ± 12.4%; 95% CI 69.6%-86.8%) compared to untreated sites (64.7% ± 17.3%; 95% CI 59.4%-83.3%). Controversially, no difference (p = .270) in terms of old bone was present between treated (3.1% ± 1.7%, 95% CI 1.8%-4.2%) and untreated implants (3.8% ± 1.9%, 95% CI 3.2%-5.8%). Significant differences (p = .018) in terms of total mineralized bone were found between treated (75.6% ± 13.0%, 95% CI 73.3%-91.3%) and untreated implants (68.4% ± 16.8%; 95% CI 64.2%-87.6%). CONCLUSIONS: Implants treated using plasma of argon was demonstrated to reach a higher bone-to-implant contact when compared to untreated implants.

Healing at the Interface Between Autologous Block Bone Grafts and Recipient Sites Using n-Butyl-2-Cyanoacrylate Adhesive as Fixation: Histomorphometric Study in Rabbits.

The aim of the present split-mouth (split-plot) study was to describe the sequential healing in the interface between autologous bone grafts and recipient parent bone, fixed using an n-butyl-2-cyanoacrylate adhesive with or without an additional titanium fixation screw. Bone grafts were collected from the calvaria and fixed to the lateral aspect of the mandible in 24 rabbits. The cortical layers of the recipient sites were perforated, and the grafts were randomly fixed using an n-butyl-2-cyanocrylate adhesive, either alone or in conjunction with a 1.5 mm × 6.0 mm titanium fixation screw. The animals were sacrificed after 3, 7, 20, and 40 days, and histomorphometric evaluations of the interface between graft and parent bone were performed. Only 2 of 6 grafts in each group were partially incorporated to the parent bone after 40 days of healing. The remaining grafts were separated from the parent bone by adhesive and connective tissue. It was concluded that the use of n-butyl-2-cyanoacrylate as fixation of an autologous bone graft to the lateral aspect of the mandible was able to maintain the fixation over time but did not incorporate the graft to the recipient sites. Use of fixation screws did not improve the healing.

Enhanced biocompatibility and osseointegration of calcium titanate coating on titanium screws in rabbit femur.

This study aimed to examine the biocompatibility of calcium titanate (CaTiO3) coating prepared by a simplified technique in an attempt to assess the potential of CaTiO3 coating as an alternative to current implant coating materials. CaTiO3-coated titanium screws were implanted with hydroxyapatite (HA)-coated or uncoated titanium screws into medial and lateral femoral condyles of 48 New Zealand white rabbits. Imaging, histomorphometric and biomechanical analyses were employed to evaluate the osseointegration and biocompatibility 12 weeks after the implantation. Histology and scanning electron microscopy revealed that bone tissues surrounding the screws coated with CaTiO3 were fully regenerated and they were also well integrated with the screws. An interfacial fibrous membrane layer, which was found in the HA coating group, was not noticeable between the bone tissues and CaTiO3-coated screws. X-ray imaging analysis showed in the CaTiO3 coating group, there was a dense and tight binding between implants and the bone tissues; no radiation translucent zone was found surrounding the implants as well as no detachment of the coating and femoral condyle fracture. In contrast, uncoated screws exhibited a fibrous membrane layer, as evidenced by the detection of a radiation translucent zone between the implants and the bone tissues. Additionally, biomechanical testing revealed that the binding strength of CaTiO3 coating with bone tissues was significantly higher than that of uncoated titanium screws, and was comparable to that of HA coating. The study demonstrated that CaTiO3 coating in situ to titanium screws possesses great biocompatibility and osseointegration comparable to HA coating.

Fabrication of a Biodegradable Implant with Tunable Characteristics for Bone Implant Applications.

Biodegradable polymers are appealing material for the manufacturing of surgical implants as such implants break down in vivo, negating the need for a subsequent operation for removal. Many biocompatible polymers produce acidic breakdown products that can lead to localized inflammation and osteolysis. This study assesses the feasibility of fabricating implants out of poly(propylene carbonate) (PPC)-starch that degrades into CO2 and water. The basic compression modulus of PPC-starch (1:1 w/w) is 34 MPa; however, the addition of glycerol (1% w/w) and water as plasticizers doubles this value and enhances the surface wettability. The bioactivity and stiffness of PPC-starch blends is increased by the addition of bioglass microparticles (10% w/w) as shown by in vitro osteoblast differentiation assay and mechanical testing. MicroCT analysis confirms that the bioglass microparticles are evenly distributed throughout biomaterial. PPC-starch-bioglass was tested in vivo in two animal models. A murine subcutaneous pellet degradation assay demonstrates that the PPC-starch-bioglass blend's volume fraction loss is 46% after 6 months postsurgery, while it is 27% for poly(lactic acid). In a rat knee implantation model, PPC-starch-bioglass screws inserted into the distal femur show osseointegration with no localized adverse effects after 3 and 12 weeks. These data support the further development of PPC-starch-bioglass as a medical biomaterial.

Influence of Implants Surface Properties on Bone Tissue Formation in the Ectopic Osteogenesis Test.

We studied the influence of the characteristics of oxide porous coatings on osteogenesis and integration of new bone tissue and titanium implant surface in the ectopic osteogenesis test. Implants with coating with pore size 2-20 µ exhibit better osteogenic and osteoconductive characteristics than implants with homogenous surface and smooth relief (pore size 0.5-5.0 µ). Physical characteristics of the surface of the material along with chemical composition of the coating are essential for the formation of bone tissue and its integration with the implant.

Complications of intramedullary nailing-Evolution of treatment.

Intramedullary nailing of diaphyseal long bone fractures is a standard procedure in today's trauma and orthopedic surgery due to the numerous advantages (e.g. minimal invasive, limited soft tissue damage, load stability). In the last decade indications have been extended to the metaphyseal region. This was associated with problems and complications due to the reduced bone-implant interface. The changed anatomical conditions lead to decreased implant anchorage. Newly developed locking solutions overcome most of these problems. First, the number and also the orientation of the locking screws were adapted to allow a multiplanar locking. This results in increased implant anchorage in the soft metaphyseal bone, thus construct stability significantly improved. Additional options like angular stable locking have been introduced and furthermore enhanced construct stability especially in poor bone stock. As a perspective locking screw augmentation shows promising results in first biomechanical testing.

Correlation between pre-operative buccal bone thickness and soft tissue changes around immediately placed and restored implants in the maxillary anterior region: A 2-year prospective study.

OBJECTIVES: This study evaluated the correlation between pre-operative buccal cortical bone thickness and peri-implant tissue response following immediate placement and restoration of implants in the maxillary aesthetic zone. MATERIAL AND METHODS: Eighteen patients (3 males, 15 females) with an age range of 19-57 years requiring the replacement of a single maxillary anterior tooth were included in this prospective study. Patients were selected on the basis of defined criteria: intact socket walls, absence of any acute infection in the sockets, absence of any gingival marginal pathology and attainment of a high primary stability (≥30 Ncm) at implant placement. Regardless of buccal bone thickness, all participating patients underwent the same treatment strategy that involved removal of the failed tooth, flapless surgery, immediate implant placement, grafting of the implant-socket gap and connection of a screw-retained provisional restoration. Buccal bone thickness was evaluated using pre-operative CBCT scans. Intra-oral photographs were taken before implant placement (baseline) and at 1- and 2-year follow-up to assess soft tissue changes around the implants. Aesthetic evaluation was carried out using the pink esthetic score (PES). RESULTS: All implants remained osseointegrated during the follow-up period of 2 years with mesial papilla, distal papilla, and mid-facial gingiva showing a mean recession of 0.06 ± 0.71 mm, 0.25 ± 0.78 mm, and 0.22 ± 0.83 mm, respectively. Pink esthetic score values improved from a median value of 9 (IQR 8.75-10.25) pre-operatively to 11 (IQR 9.75-12) at the end of 2 years. No significant correlation was found between buccal bone thickness (range 0.45-1.24 mm) and soft tissue or aesthetic changes. CONCLUSIONS: Within the limits of this study, no significant correlation could be found between pre-operative buccal bone width and the soft tissue and aesthetic outcome following immediate implant placement and restoration in the anterior maxilla. Therefore, favourable clinical and aesthetic outcomes could be achieved by applying a strict selection criteria and treatment protocol regardless of the initial thickness of the buccal bone.

Buccal bone thickness around single dental implants in the maxillary esthetic zone.

OBJECTIVE: To compare the thickness of buccal bone around single dental implants placed in the anterior maxilla (premolar to premolar) inserted with different placement protocols. DATA SOURCES: An electronic search was conducted using MEDLINE (PubMed), Cochrane Central Register of Controlled Trials (CENTRAL), and EMBASE, from January 1980 to July 2015. Mean buccal bone thickness around single dental implants was measured and correlation with implant placement protocols, loading protocols, and augmentation method was assessed. A Q-test was used to access the homogeneity of levels of effect. A univariate meta-regression analysis was used for further investigation of the between-study heterogeneity. Two randomized clinical trials and 12 cohort studies were included for statistical analysis. The difference in buccal bone thickness for implants placed with different implant placement protocols (early vs immediate vs delayed) was not statistically significant (P > .05). Loading protocols (immediate vs delayed) also did not significantly influence the thickness of buccal bone. Descriptive analysis showed different buccal bone thickness for dental implants that received different bone grafting materials at the time of placement. CONCLUSION: Different implant placement and loading protocols may not significantly affect the thickness of the buccal bone around single dental implants in the anterior maxilla. Different bone graft materials at the time of implant placement may have an effect on buccal bone thickness.

Enhancement of Orthodontic Anchor Screw Stability Under Immediate Loading by Ultraviolet Photofunctionalization Technology.

PURPOSE: Ultraviolet (UV)-mediated photofunctionalization technology is intended to enhance the osseointegration capability of titanium implants. There are concerns about orthodontic anchor screws loosening under immediate loading protocols in adolescent orthodontic treatment. The purpose of this in vivo study was to evaluate the effects of photofunctionalization on the intrabony stability of orthodontic titanium anchor screws and bone-anchor screw contact under immediate loading in growing rats. MATERIALS AND METHODS: Custom-made titanium anchor screws (1.4 mm in diameter and 4.0 mm in length) with or without photofunctionalization pretreatment were placed on the proximal epiphysis of the tibial bone in 6-week-old male Sprague-Dawley rats and were loaded immediately after placement. After 2 weeks of loading, the stability of the anchor screws was evaluated using a Periotest device, and the bone-anchor screw contact ratio (BSC) was assessed by a histomorphometric analysis using field-emission scanning electron microscopy. RESULTS: In the unloaded group, Periotest values (PTVs) were ~25 for UV-untreated screws and 13 for UVtreated screws (P < .01), while in the immediate-loading group, PTVs were 28 for UV-untreated screws and 16 for UV-treated screws (P < .05). Significantly less screw mobility was observed in both UV-treated groups regardless of the loading protocol. The BSC was increased ~1.8 fold for UV-treated screws, compared with UV-untreated screws, regardless of the loading protocol. CONCLUSION: Photofunctionalization enhanced the intrabony stability of orthodontic anchor screws under immediate loading in growing rats by increasing bone-anchor screw contact.

Different configuration of socket shield technique in peri-implant bone preservation: An experimental study in dog mandible.

The aim of this study was to evaluate the influence of the residual root and peri implant bone dimensions on the clinical success of the socket shield technique. Thirty-six dental implants were installed in 6 dogs. The clinical crowns of teeth P3, P4 and M1 were beheaded. Afterwards, the roots were worn down 2-3mm in apical direction until they were located at crestal level. Posterior implant beds were prepared in the center of the roots passing by 3mm apically forming 6 groups in accordance to the remaining root thickness. Radiography of the crestal bone level was performed on day 0 and after 12 weeks. Histomorphometric analyses of the specimens were carried out to measure the crestal bone level, the bone to implant contact and the buccal and lingual bone thickness at the implant shoulder portion. Correlations between groups were analyzed through nonparametric Friedman test, statistical significance was set as p<0.05. All 36 implants were osseointegrated, but 3 samples showed a clinical inflammatory reaction and some radicular fragments presented a small resorption process. On the buccal and lingual side, the radicular fragment was attached to the buccal bone plate by a physiologic periodontal ligament. In the areas where there was space between the implant and the fragment, newly formed bone was demonstrated directly on the implant surface. Within the limitations of an animal pilot study, root-T belt technique may be beneficial in preserving and protecting the bundle bone and preservation of soft tissues. If the thickness of the buccal bone is 3mm, and the thickness of the remaining root fragment is 2mm, the socket shield technique is more predictable and the bone contours can be maintained.

Laser-Modified Surface Enhances Osseointegration and Biomechanical Anchorage of Commercially Pure Titanium Implants for Bone-Anchored Hearing Systems.

Osseointegrated implants inserted in the temporal bone are a vital component of bone-anchored hearing systems (BAHS). Despite low implant failure levels, early loading protocols and simplified procedures necessitate the application of implants which promote bone formation, bone bonding and biomechanical stability. Here, screw-shaped, commercially pure titanium implants were selectively laser ablated within the thread valley using an Nd:YAG laser to produce a microtopography with a superimposed nanotexture and a thickened surface oxide layer. State-of-the-art machined implants served as controls. After eight weeks' implantation in rabbit tibiae, resonance frequency analysis (RFA) values increased from insertion to retrieval for both implant types, while removal torque (RTQ) measurements showed 153% higher biomechanical anchorage of the laser-modified implants. Comparably high bone area (BA) and bone-implant contact (BIC) were recorded for both implant types but with distinctly different failure patterns following biomechanical testing. Fracture lines appeared within the bone ~30-50 µm from the laser-modified surface, while separation occurred at the bone-implant interface for the machined surface. Strong correlations were found between RTQ and BIC and between RFA at retrieval and BA. In the endosteal threads, where all the bone had formed de novo, the extracellular matrix composition, the mineralised bone area and osteocyte densities were comparable for the two types of implant. Using resin cast etching, osteocyte canaliculi were observed directly approaching the laser-modified implant surface. Transmission electron microscopy showed canaliculi in close proximity to the laser-modified surface, in addition to a highly ordered arrangement of collagen fibrils aligned parallel to the implant surface contour. It is concluded that the physico-chemical surface properties of laser-modified surfaces (thicker oxide, micro- and nanoscale texture) promote bone bonding which may be of benefit in situations where large demands are imposed on biomechanically stable interfaces, such as in early loading and in compromised conditions.

Evaluation of the surface characteristics of anodic oxidized miniscrews and their impact on biomechanical stability: An experimental study in beagle dogs.

INTRODUCTION: In this study, we aimed to assess the surface characteristics and the biomechanical stability of miniscrews with an anodic oxidized surface compared with machined surface miniscrews in beagle dogs. METHODS: Self-drilled, titanium-aluminum-vanadium alloy miniscrews with an anodic oxidized surface (n = 48) or a machined surface (n = 48) were placed into the mandibles of 12 beagle dogs. The surface characteristics of both types of miniscrews were analyzed before implantation with scanning electron microscopy and atomic force microscopy. Insertion torque was measured during placement of all 96 miniscrews. Half of the implants in each group (24 specimens per subgroup) received 200 to 250 g of tensile force for 3-week or 12-week loading periods. Removal torque was measured in 12 specimens of each subgroup, and bone-implant contact and bone volume were quantified in the other 12 specimens of each subgroup. RESULTS: Atomic force microscopy measurements demonstrated that the anodic oxidized surface miniscrews had significantly higher roughness parameters than did the machined surface miniscrews (P < 0.001). The 2 types of miniscrews were not significantly different in insertion and removal torque values or in bone-implant contacts and bone volumes, regardless of the loading period. CONCLUSIONS: Anodic oxidized miniscrews have different surface roughness profiles but no clinically significant superiority in biomechanical stability compared with machined surface miniscrews.

Biograft Block Hydroxyapatite: A Ray of Hope in the Reconstruction of Maxillofacial Defects.

BACKGROUND: Improving quality of human life has been the rationale for increase in the applications of bone substitute materials for bone regeneration. High prevalence of loss of bone tissue due to disease remains a major challenge for reconstruction. Shortcomings of autografts and allografts have made the clinicians go for artificial implant materials. AIM AND OBJECTIVE: To prospectively study the structural and esthetic reconstruction of resected mandibular site with biograft porous block hydroxyapatite (BBHA). The study evaluated the efficacy of BBHA as a material for reconstruction of large bone defects. METHODS: Patients requiring reconstruction after resection of cyst/tumors and who denied conventional reconstruction were enrolled for BBHA reconstruction during 2008 to 2015. All patients were clinically and radiologically followed and assessed for a range of 4 to 60 months for outcome. RESULTS: During follow-up periods no one had infection, dissolution, migration, or absorption, but new bone formation and bridging observed in proximity with graft and bone interface. CONCLUSION: Structural and esthetic reconstruction using BBHA significantly reduces donor site morbidity. BBHA have satisfactory results in relation to esthetics and are useful material for reconstruction. Clinical application of this technique will minimize an additional surgical procedure required to harvest donor bone. BBHA provides good esthetics and structural balance to face. As this is an ongoing study the outcome is expected to improve. The incorporation of implants in the BBHA block may fulfill the function also in near future.

Laser-treated stainless steel mini-screw implants: 3D surface roughness, bone-implant contact, and fracture resistance analysis.

BACKGROUND/OBJECTIVES: This study investigated the biomechanical properties and bone-implant intersurface response of machined and laser surface-treated stainless steel (SS) mini-screw implants (MSIs). MATERIAL AND METHODS: Forty-eight 1.3mm in diameter and 6mm long SS MSIs were divided into two groups. The control (machined surface) group received no surface treatment; the laser-treated group received Nd-YAG laser surface treatment. Half in each group was used for examining surface roughness (Sa and Sq), surface texture, and facture resistance. The remaining MSIs were placed in the maxilla of six skeletally mature male beagle dogs in a randomized split-mouth design. A pair with the same surface treatment was placed on the same side and immediately loaded with 200 g nickel-titanium coil springs for 8 weeks. After killing, the bone-implant contact (BIC) for each MSI was calculated using micro computed tomography. Analysis of variance model and two-sample t test were used for statistical analysis with a significance level of P <0.05. RESULTS: The mean values of Sa and Sq were significantly higher in the laser-treated group compared with the machined group (P <0.05). There were no significant differences in fracture resistance and BIC between the two groups. LIMITATION: animal study CONCLUSIONS/IMPLICATIONS: Laser treatment increased surface roughness without compromising fracture resistance. Despite increasing surface roughness, laser treatment did not improve BIC. Overall, it appears that medical grade SS has the potential to be substituted for titanium alloy MSIs.