Biomedical subjects

R M Pilliar

Publications and source records attributed to R M Pilliar.

At least 19 recordsLinked to original sources

PubMed2006

Substrate porosity enhances chondrocyte attachment, spreading, and cartilage tissue formation in vitro.

Tissue engineering is being explored as a new approach to treat damaged cartilage. As the biomaterial used may influence tissue formation, the effects of substrate geometry on chondrocyte behavior in vitro were examined. Articular chondrocytes were isolated and cultured on the surface of smooth, rough, porous-coated, and fully porous Ti-6Al-4V substrates. The percentage of chondrocytes that attached to each substrate at 24 h was determined. After 24 and 72 h, chondrocytes were visualized by scanning electron microscopy and cell areas were measured. Collagen and proteoglycan accumulation within the first 24 h was determined by incorporation with [3H]-proline and [35S]-SO4, respectively. Chondrocyte attachment as well as matrix accumulation was enhanced as substrate surface area increased. Cell areas on the fully porous substrate were over four times greater than on any other substrate by 72 h in culture. After 8 weeks in culture, a continuous layer of cartilaginous tissue formed only on the surface of the fully porous substrate. This suggests that fully porous Ti-6Al-4V substrates provide the conditions that favor cartilage tissue formation by influencing cell attachment and extent of cell spreading. Understanding how substrate porosity influences chondrocyte behavior may help identify methods to further enhance cartilage tissue formation in vitro.

Alloys↗

PubMed2006

Cyclic compressive mechanical stimulation induces sequential catabolic and anabolic gene changes in chondrocytes resulting in increased extracellular matrix accumulation.

Overcoming the limited ability of articular cartilage to self-repair may be possible through tissue engineering. However, bioengineered cartilage formed using current methods does not match the physical properties of native cartilage. In previous studies we demonstrated that mechanical stimulation improved cartilage tissue formation. This study examines the mechanisms by which this occurs. Application of uniaxial, cyclic compression (1 kPa, 1 Hz, 30 min) significantly increased matrix metalloprotease (MMP)-3 and MMP-13 gene expression at 2 h compared to unstimulated cells. These returned to constitutive levels by 6 h. Increased MMP-13 protein levels, both pro- and active forms, were detected at 6 h and these decreased by 24 h. This was associated with tissue degradation as more proteoglycans and collagen had been released into the culture media at 6 h when compared to the unstimulated cells. This catabolic change was followed by a significant increase in type II collagen and aggrecan gene expression at 12 h post-stimulation and increased synthesis and accumulation of these matrix molecules at 24 h. Mechanical stimulation activated the MAP kinase pathway as there was increased phosphorylation of ERK1/2 and JNK as well as increased AP-1 binding. Mechanical stimulation in the presence of the JNK inhibitor, SP600125, blocked AP-1 binding preventing the increased gene expression of MMP-3 and -13 at 2 h and type II collagen and aggrecan at 12 h as well as the increased matrix synthesis and accumulation. Given the sequence of changes, cyclic compressive loading appears to initiate a remodelling effect involving MAPK and AP-1 signalling resulting in improved in vitro formation of cartilage.

Animals↗

PubMed2005

A single application of cyclic loading can accelerate matrix deposition and enhance the properties of tissue-engineered cartilage.

OBJECTIVE: Mechanical stimulation is a widely used method to enhance the formation and properties of tissue-engineered cartilage. While studies have evaluated the responsiveness of chondrocytes to mechanical stimuli, little is known about how much stimulation is actually required. Thus, the purpose of this study was to investigate the effect of a single application of cyclic loading to chondrocytes on the formation and properties of in vitro-formed tissue. DESIGN: Isolated bovine articular chondrocytes were seeded on ceramic substrates in 3D culture and subjected to a single application of compressive cyclic loading at 1, 8 or 15 days after seeding. Once the time at which the chondrocytes were most sensitive to mechanical loading was determined, the effect of a single application on the synthesis and accumulation of matrix molecules as well as the mechanical properties of the in vitro-formed cartilage tissue was evaluated. RESULTS: Chondrocytes were more responsive to cyclic loading applied early in culture. Cyclic forces applied 24 h after the cultures were established increased collagen and proteoglycan syntheses (48 +/- 11% and 49 +/- 11%, respectively). This single application of cyclic loading also increased the accumulation of collagen (stimulated: 207 +/- 20 microg, control: 173 +/- 9 microg) and proteoglycans (stimulated: 302 +/- 24 microg, control: 270 +/- 14 microg) as well as improved the mechanical properties of the in vitro-formed tissue (twofold increase in equilibrium stress and modulus) determined 4 weeks after the applied stimulus. CONCLUSIONS: A single application of cyclic loading to chondrocytes early in culture increased matrix accumulation and enhanced the mechanical properties of the in vitro-formed tissue. This suggests that mechanical forces do not have to be applied intermittently over long periods of time to accelerate in vitro tissue formation.

Animals↗

PubMed2004

The effect of sol-gel-formed calcium phosphate coatings on bone ingrowth and osteoconductivity of porous-surfaced Ti alloy implants.

Ti-6Al-4V implants formed with a sintered porous surface for implant fixation by bone ingrowth were prepared with or without the addition of a thin surface layer of calcium phosphate (Ca-P) formed using a sol-gel coating technique over the porous surface. The implants were placed transversely across the tibiae of 17 rabbits. Implanted sites were allowed to heal for 2 weeks, after which specimens were retrieved for morphometric assessment using backscattered scanning electron microscopy and quantitative image analysis. Bone formation along the porous-structured implant surface, was measured in relation to the medial and lateral cortices as an indication of implant surface osteoconductivity. The Absolute Contact Length measurements of endosteal bone growth along the porous-surfaced zone were greater with the Ca-P-coated implants compared to the non-Ca-P-coated implants. The Ca-P-coated implants also displayed a trend towards a significant increase in the area of bone ingrowth (Bone Ingrowth Fraction). Finally, there was significantly greater bone-to-implant contact within the sinter neck regions of the Ca-P-coated implants.

Alloys↗

PubMed2004

A targeted review of study outcomes with short (< or = 7 mm) endosseous dental implants placed in partially edentulous patients.

BACKGROUND: Generally, threaded root-form endosseous dental implants are thought to perform poorly in short lengths (i.e., < 10 mm). However, whether modifications in implant surface geometry will improve performance of short threaded implants is less clear. METHODS: The relationship between dental implant failure rates and their surface geometry, length, and location (maxilla versus mandible) was explored in the published literature. Using a MEDLINE search (1985 through 2001), studies were sought with the following criteria: 1) data suitable to calculate failure rates of implant lengths < or = 7 mm versus > 7 mm; 2) data separable into maxillary versus mandibular results; 3) criteria for "failure" clearly defined; and 4) minimal functional period of 2 years. RESULTS: Twelve papers were identified as follows: eight with machined threaded implants, two with acid-treated threaded implants, and two with sintered porous-surfaced press-fit implants. The following results were found: 1) machined surface implants experienced greater failure rates than textured surface implants; 2) with the exception of sintered porous-surfaced implants, 7 mm long dental implants appear to have higher failure rates than those > 7 mm length; and 3) with textured surface implants, higher failure rates were more likely in the maxilla than in the mandible, but with machined surface implants there were no differences in failure rates between maxilla and mandible. CONCLUSIONS: Dental implant surface geometry is a major determinant in how well these implants perform in short lengths, defined here as lengths of < or = 7 mm. While threaded implants show higher failure rates in short versus longer lengths, sintered porous-surfaced implants perform well in the defined "short" lengths. More studies are needed to better assess the performance of short, acid-washed threaded implants.

Analysis of Variance↗

PubMed2002

Porous calcium polyphosphate scaffolds for bone substitute applications in vivo studies.

Porous rods (6 mm in length and 4 mm in diameter) of calcium polyphosphate (CPP) made by gravity sintering of particles in the size ranges of 45-105, 105-150. and 150-250 microm and with initial volume percent porosity in the range of 35-45% were implanted in the distal femur of New Zealand white rabbits. In an initial experiment, four rabbits implanted with rods made from coarse particles (150-250 microm) were sacrificed at each of the following time points: 2 days, 2 weeks, 6 weeks and 12 weeks. In a subsequent experiment, 10 rabbits were implanted with rods made by sintering 45-105 microm particles and another 10 were made by using particles of 105-150 microm. These rabbits were sacrificed at 6 weeks (five rabbits) and 1 year (five rabbits). No adverse reaction was found histologically at any time point in either experiment. These experiments show that CPP macroporous rods can support bone ingrowth and that between 12 weeks and 1 year, the amount of bones formed is equivalent to the natural bone volume found at similar sites. The degradation of the CPP material is inversely proportional to the original particle size and is rapid initially (within the first 6 weeks) and slows down thereafter. In conclusion, this material seems to promote rapid bone ingrowth and can be tailored to degrade at a given rate in vivo to some degree through appropriate selection of the starting particle size.

Animals↗

PubMed2001

Fabrication of porous calcium polyphosphate implants by solid freeform fabrication: a study of processing parameters and in vitro degradation characteristics.

Solid freeform fabrication (SFF) involves the creation of a solid 3-D object of desired shape by successively adding raw materials in particles or layers. Its use in fabricating surgical implants is being explored. The objective of this study was to determine the feasibility of using SFF to build porous parts of calcium polyphosphate (CPP), a linear condensed phosphate that has been suggested as a material for forming bioresorbable skeletal replacement implants. CPP powders (<25 microm in particle size) were added to an UV curable monomer (SOMOS 6110) at a solids loading of 25 vol %, with the addition of a commercial dispersant to prevent particle agglomeration and settling. Viscosity and cure depth measurements were performed to insure that CPP suspension met the requirements deemed necessary for use in SFF. The CPP suspension was bulk cured and sintered in molds in order to assess binder removal and sintering parameters. Using a three-point bend test, the ultimate bending strength and energy-to-fracture of sintered CPP samples simulating parts to be formed by this strategy were characterized. In vitro degradation studies using 0.1M of tris-buffered solution were performed to assess the effect of aging on mechanical properties of the samples as a function of the processing route and resulting structures. The polymer binder successfully was removed from the cured ceramic suspension by developing a procedure that combined slow heating rates with low temperature dwells. Sintering CPP at 585 degrees C for 1 h produced amorphous material samples with average porosity of 27.7 +/- 2.0%. Sintering CPP at 600 degrees C for 1 h produced a crystalline material with samples having an average porosity of 22.9 +/- 1.3%. Crystalline CPP was found to exhibit superior bend strength and toughness compared with amorphous CPP. Both samples experienced a decline in mechanical properties during in vitro degradation; however, the effects were more pronounced with the amorphous CPP samples. Amorphous CPP was found to degrade four times faster than crystalline CPP, as shown by high levels of phosphate present in the degradation solution and a noticeable increase in the porosity of the samples. Crystalline CPP was more resistant to attack as dissolution was limited to surface features of the sintered particles.

Biocompatible Materials↗

PubMed2001

The fretting corrosion resistance of PVD surface-modified orthopedic implant alloys.

The objective of this study was to evaluate the fretting corrosion resistance of both modified and unmodified Ti6Al4V flats fretted against CoCr-alloy spheres in a buffered Hank's solution at 37 degrees C using an original fretting apparatus. A physical vapor deposition (PVD) cathodic arc evaporation technique was used to deposit 3-4 microm thick titanium nitride (TiN), zirconium nitride (ZrN), or amorphous carbon (AC) coatings onto the Ti6Al4V substrates. The fretting behavior of the nitride films (TiN and ZrN) was characterized by the absence of surface damage and the deposition of a Cr-rich oxide transferred from the CoCr-alloy spheres to the modified surfaces. This oxide led to a slight increase in surface roughness. Three of the six multilayered AC coatings tested exhibited extensive fretting damage and generated large, deep, wear scars. Cohesive failure of the AC coating was observed in the low contact stress areas of the fretting scars. The remaining AC-coated specimens experienced only slight polishing wear. The reason for the different behavior within the AC-coated specimens is not clear at the present time. The unmodified Ti6Al4V surfaces experienced severe surface damage consistent with the adhesive galling mechanism to which these alloys are susceptible.

Arthroplasty, Replacement, Hip↗

PubMed2001

Mechanical regulation of localized and appositional bone formation around bone-interfacing implants.

The local mechanical environment around bone-interfacing implants determines, in large part, whether bone formation leading to functional osseointegration will occur. Previous attempts to relate local peri-implant tissue strains to tissue formation have not accounted for implant surface geometry, which has been shown to influence early tissue healing in vivo. Furthermore, the process by which mechanically regulated peri-implant bone formation occurs has not been considered previously. In the current study, we used a unit cell approach and the finite element method to predict the local tissue strains around porous-surfaced and plasma-sprayed implants, and compared the predictions to patterns of bone formation reported in earlier in vivo experiments. Based on the finite element predictions, we determined that appositional bone formation occurred when the magnitudes of the strain components at the tissue-host bone interface were <8%. Localized, de novo bone formation occurred when the distortional tissue strains were less than approximately 3%. Based on these threshold tissue strains, we propose a mechanoregulatory model to relate local tissue strains to the process of peri-implant bone formation. The mechanoregulatory model is novel in that it predicts both appositional and localized bone formation and its predictions are dependent on implant surface geometry. The model provides initial criteria with which the osseointegration potential of bone-interfacing implants may be evaluated, particularly under conditions of immediate or early loading.

Alloys↗

PubMed2001

Effect of material geometry on cartilagenous tissue formation in vitro.

The effect of material geometry, as defined by average pore size, on chondrocyte phenotype and cartilagenous tissue formation in vitro was examined. Bovine articular chondrocytes were plated on porous titanium alloy (Ti6Al4V) discs of different average pore sizes (13, 43, and 68 microm) and grown in culture for 4 weeks. Chondrocyte phenotype was maintained as indicated by the synthesis of large proteoglycans (Kav +/- SD: 13 microm = 0.28 +/- 0.01; 43 microm = 0.29 +/- 0.01; 68 microm = 0.27 +/- 0.02) and type II collagen. Light microscopical examination of histological sections of the composites showed that cartilagenous tissue had formed on all discs. The cartilagenous tissue on the discs of the smallest average pore size (13 microm) was significantly thicker than the tissue on the discs of larger average pore sizes and also had greater amounts of proteoglycan [mean glycosaminoglycan content +/- SD microg/disc): 13 microm = 246.9 +/- 7.8; 43 microm = 190.4 +/- 10.2; 68 microm = 156.6 +/- 25.8, p = 0.002] and DNA [mean DNA content +/- SD microg/disc): 13 microm = 12.5 +/- 0.6; 43 microm = 8.3 +/- 0.2; 68 microm = 9.3 +/- 0.9, p = 0.0008]. However, the amount of proteoglycan accumulated per cell was similar in the tissues generated on the discs of different average pore sizes. In contrast, the amount of collagen in the cartilagenous tissues showed no significant differences between the different pore sizes, but the amount of collagen accumulated per cell was less in the tissue formed on the smallest pore size disc (13 microm) as compared with the tissue formed on the discs of the larger pore sizes [mean hydroxyproline content/DNA (microg/microg) +/- SD: 13 microm = 1.56 +/- 0.2; 43 microm = 2.19 +/- 0.2; 68 microm = 2.3 +/- 0.3]. These results suggest that material geometry, as defined by pore size, can affect the amount and composition of the cartilagenous tissue that forms.

Alloys↗

PubMed2001

Porous calcium polyphosphate scaffolds for bone substitute applications -- in vitro characterization.

Porous structures were formed by gravity sintering calcium polyphosphate (CPP) particles of either 106-150 or 150-250 microm size to form samples with 30-45 vol% porosity with pore sizes in the range of 100 microm (40-140 microm). Tensile strength of the samples assessed by diametral compression testing indicated relatively high values for porous ceramics with a maximum strength of 24.1 MPa for samples made using the finer particles (106-150 microm). X-ray diffraction studies of the sintered samples indicated the formation of beta-CPP from the starting amorphous powders. In vitro aging in 0.1 M tris-buffered solution (pH 7.4) or 0.05 M potassium hydrogen phthalate buffered solution (pH 4.0) at 37 degreesC for periods up to 30d indicated an initial rapid loss of strength and P elution by 1 d followed by a more gradual continuing strength and P loss resulting in strengths at 30d equal to about one-third the initial value. The observed structures, strengths and in vitro degradation characteristics of the porous CPP samples suggested their potential usefulness as bone substitute materials pending subsequent in vivo behaviour assessment.

Bone Substitutes↗

PubMed2001

Fracture resistance of dentin-composite interfaces using different adhesive resin layers.

OBJECTIVES: The objective of this study was to study the effect of different adhesive layers on the interfacial fracture toughness (K(ICi)) of dentin-resin composite interfaces. METHODS: Miniature short-rod fracture toughness specimens containing a chevron-shaped dentin-bonded interface along their midplane were used for testing. Each interface zone contained a thinned (one coat of unfilled adhesive resin, air-thinned), one-layer (one coat of unfilled adhesive resin, brush-thinned), two-layer (two coats of unfilled adhesive resin, brush-thinned), 10% filled or 45% filled adhesive resin layer. After storage in distilled water at 37 degrees C for 24h, the fracture toughness test specimens were loaded in tension at an extension rate of 0.5mm/min until fracture and the K(ICi) were determined. The results were analysed by ANOVA and Fisher's LSD test (p<0.05). Scanning electron microscopy was used to examine representative fracture surfaces. RESULTS: There were no significant differences in mean K(ICi) among the different unfilled adhesive resin layer groups. SEM examination of these specimens showed that fracture generally occurred between the resin-infiltrated layer and adhesive resin layer during interfacial fracture toughness testing. The mean K(ICi) for the 10% filled groups was not significantly different from the unfilled groups. The 45% filled group, however, demonstrated the highest K(ICi) values, the thickest adhesive resin layer under SEM examination, and a fracture path through the adhesive resin layer. CONCLUSIONS: There were no significant differences in K(ICi) when the unfilled adhesive resin was used despite different application methods. The 45% filled adhesive resin improved the properties of the dentin-composite interface with respect to both interfacial fracture resistance and dentinal seal after fracture.

Acid Etching, Dental↗

PubMed2001

Differences in osseointegration rate due to implant surface geometry can be explained by local tissue strains.

Experimental evidence indicates that the surface geometry of bone-interfacing implants influences the nature and rate of tissues formed around implants. In a previously reported animal model study, we showed that non-functional, press-fitted porous-surfaced implants placed in rabbit femoral condyle sites osseointegrated more rapidly than plasma-sprayed implants. We hypothesized that the accelerated osseointegration observed with the porous-surfaced design was the result of this design providing a local mechanical environment that was more favourable for bone formation. In the present study, we tested this hypothesis using finite element analysis and homogenization methods to predict the local strains in the pre-mineralized tissues formed around porous-surfaced and plasma-sprayed implants. We found that, for loading perpendicular to the implant interface, the porous surface structure provided a large region that experienced low distortional and volumetric strains, whereas the plasma-sprayed implant provided little local strain protection to the healing tissue. The strain protected region, which was within the pores of the sintered porous surface layer. corresponded to the region where the difference in the amount of mineralization between the two implant designs was the greatest. Low distortional and volumetric strains are believed to favour osteogenesis, and therefore the model results provide initial support for the hypothesis that the porous-surfaced geometry provides a local mechanical environment that favours more rapid bone formation in certain situations.

Animals↗

PubMed2001

Characterization of nucleus pulposus-like tissue formed in vitro.

In order to be able to study the metabolism of nucleus pulposus (NP) tissue, we developed a cell culture system that resulted in the formation of NP-like tissue in vitro. NP cells were isolated from sheep lumbar spines and grown on filter inserts (Millicell CM). Histological examination showed that the cells accumulated extracellular matrix and formed a continuous layer of NP-like tissue. The accumulation of sulfated proteoglycans in the NP-like tissue continued up to 10 weeks and this was paralleled by an increase in tissue thickness and dry weight. DNA content remained stable during the first 4 weeks but then decreased over time. The amount of DNA, glycosaminoglycan (GAG) and collagen per mg dry weight of the tissue generated after 10 weeks in culture were 1.25+/-0.02, 301.6+/-27.7 and 411+/-65 microg, respectively, compared with 1.04+/-0.08, 320.6+/-21.2 and 399+/-4.4 microg (mean +/- SEM) for the in vivo tissue. There was no significant difference between in vitro and in vivo tissue. The cells in culture synthesized large proteoglycans (kav = 0.26+/-0.03, mean +/- S.D.) which were similar in size to those synthesized by cells in NP tissue in ex vivo culture (kav = 0.22+/-0.02, mean +/- S.D.) as determined by Sepharose CL-2B column chromatography. The in vitro generated tissue contained type II collagen as demonstrated by sodium dodecyl sulfate-polyacrylamide gel (SDS-PAGE) and silver staining as well as Western blot analysis. NP cells grown on filters generate tissue similar in composition to the in vivo tissue, for the characteristics examined to date, and should be a suitable model to use to study NP metabolism and extracellular matrix turnover.

Animals↗

PubMed2000

The effect of interface stiffness on dentin-composite interfacial fracture resistance.

OBJECTIVES: The dentin-composite interface should withstand stresses that develop initially during composite polymerization and later during clinical function. The elastic behavior of the dentin-composite interface, which could be represented by an interfacial stiffness parameter, is not completely understood. The purpose of this study was to measure the relative interfacial stiffness of dentin-composite interfaces formed using commercially available dentin bonding agents and to relate these relative interfacial stiffness results to previously reported interfacial fracture toughness (K(ICi)) values. METHODS: The miniature short-rod fracture toughness specimen geometry containing a dentin-composite interface was used for testing. Specimens were aged in distilled water at 37 degrees C for 180days prior to tensile loading at an extension rate of 0.5mm/min. The relative interfacial stiffness was determined from the initial slope of the force-displacement curve that was obtained from each fracture toughness test. ANOVA, Fishers LSD, and linear regression tests were used for statistical analyses (p<0.05). RESULTS: The relative interfacial stiffnesses ranged from 16 to 92N/mm. The groups containing dentin-composite interfaces with greater depths of surface dentin demineralization generally exhibited higher interfacial stiffness than those with less dentin demineralization. Bonding to "wet" dentin produced higher relative interfacial stiffness results than bonding to "dry" dentin. A significant positive linear relationship was found among the individual (p=0.0001,r(2)=0.58) and the mean (p=0.0004,r(2)=0.97) relative interfacial stiffness and K(ICi) results. CONCLUSIONS: The significant positive relationship between the relative interfacial stiffness and K(ICi) results suggest a benefit (increased interfacial fracture resistance) of a relatively stiff dentin-composite interface.

Acid Etching, Dental↗

PubMed1999

Evaluating sol-gel ceramic thin films for metal implant applications: III. In vitro aging of sol-gel-derived zirconia films on Ti-6Al-4V.

Sol-gel-derived zirconia films were deposited onto polished Ti-6Al-4V substrates by dip-coating from an alkoxide precursor solution. No change in morphology of the zirconia film was observed after aging at 37 degrees C for 4-12 weeks in pH 4.0 buffer solution or Hanks' balanced salt solution (HBSS), although a precipitate predominantly composed of calcium phosphate was formed on those films aged in HBSS. X-ray diffraction identified the phase of the zirconia film as either cubic or tetragonal, and revealed no degradation to the monoclinic phase after aging. By a substrate straining test, the fracture strain of the coating was revealed to be 1.5%, above the yield strain of the titanium alloy substrate. At this strain level, through-thickness cracks formed in the coating where slip bands emerged from the substrate. Qualitatively, the adhesion of the film was sufficient to prevent gross delamination of the film at high strain levels, although small regions of delamination were caused by compressive buckling of the film. This behavior indicates generally good adhesion. No change in this behavior was observed after aging.

Alloys↗

PubMed1999

Osseointegration of sintered porous-surfaced and plasma spray-coated implants: An animal model study of early postimplantation healing response and mechanical stability.

The osseointegration and long-term success of bone-interfacing implants are dependent on mechanical stability of the implant relative to host bone during the early healing period. The geometric design of an implant surface may play an important role in affecting early implant stabilization, possibly by influencing tissue healing dynamics. In this study, we compared the early tissue healing response and resulting implant stability for two surface designs by characterizing the histological and mechanical properties of the healing tissue around Ti6Al4V sintered porous-surfaced and Ti plasma-sprayed implants. The implants were inserted transversely in rabbit femoral condyles and evaluated at 0, 4, 8, and 16 days postimplantation. At 4 and 8 days after implantation, the early healing tissue (fibrin and collagenous matrix) was more extensively integrated with the three-dimensional interconnected structure of the sintered porous surface than with the irregular geometry of the plasma-sprayed coating. In addition, histological examination indicated that initial matrix mineralization leading to osseointegration occurred more rapidly with the porous-surfaced implants. The more extensive tissue integration and more rapid matrix mineralization with the porous-surfaced implants were reflected in the mechanical test data, which demonstrated greater attachment strength and interfacial stiffness for the porous-surfaced implants 4 and 8 days postimplantation (p <.05). Sixteen days after implantation, both implant designs were osseointegrated and had comparable attachment characteristics. These data demonstrate that appropriate surface design selection can improve early implant stability and induce an accelerated healing response, thereby improving the potential for implant osseointegration.

Animals↗

PubMed1998

Overview of surface variability of metallic endosseous dental implants: textured and porous surface-structured designs.

A variety of successful endosseous dental implants with different surface forms are currently available for clinical use. These all achieve implant-to-bone fixation primarily (if not totally) through mechanical interlock of bone with implant surface features introduced by design or chance during implant fabrication. Equally important to establishment of rigid fixation is the rate at which it is achieved, because faster rates allow earlier implant loading and less chance of inadvertent early loading that might prevent implant "osseointegration." Investigations of surface modification to favorably affect osteoconductivity and bone bonding represent an active area of research in the field of dental implant development. This article presents a review of available surface designs and future research directions for improved devices.

Coated Materials, Biocompatible↗