Difference In Bone-to-implant Contact Research Articles

A novel auxiliary device enhances miniscrew stability under immediate heavy loading simulating orthopedic treatment.

To evaluate miniscrew stability and perform a histomorphometric analysis of the bone around the miniscrew under a load corresponding to orthopedic force. Thirty-two miniscrews were implanted into eight rabbit tibias. Auxiliary group rabbits received auxiliary devices with miniscrews (n = 8, 28 days; n = 8, 56 days), and those in the nonauxiliary control group received miniscrews without auxiliary devices (n = 8, 28 days; n = 8, 56 days). Elastics were placed between miniscrews to apply a load of 5 N. Miniscrew stability was evaluated using a Periotest. Bone-to-implant contact (BIC) and spike implantation depth were measured histomorphologically. Periotest values in the auxiliary group were significantly lower than those in the nonauxiliary group at all time periods. There was no significant difference in BIC between the auxiliary and nonauxiliary groups at 28 or 56 days postimplantation. The implantation spike depth in the auxiliary group was significantly greater at 56 days compared to that at 28 days. Newly formed bone was observed around the spike of the auxiliary device at 56 days. The results suggest that the use of miniscrews in conjunction with auxiliary devices provides stable skeletal anchorage, which may be useful in orthopedic treatments.

A systematic review on the effect of inorganic surface coatings in large animal models and meta-analysis on tricalcium phosphate and hydroxyapatite on periimplant bone formation.

The aim of the present systematic review was to analyse studies using inorganic implant coatings and, in a meta‐analysis, the effect of specifically tricalcium phosphate (TCP) and hydroxyapatite (HA) implant surface coatings on bone formation according to the PRISMA criteria. Inclusion criteria were the comparison to rough surfaced titanium implants in large animal studies at different time points of healing. Forty studies met the inclusion criteria for the systematic review. Fifteen of these analyzed the bone‐to‐implant contact (BIC) around the most investigated inorganic titanium implant coatings, namely TCP and HA, and were included in the meta‐analysis. The results of the TCP group show after 14 days a BIC being 3.48% points lower compared with the reference surface. This difference in BIC decreases to 0.85% points after 21–28 days. After 42–84 days, the difference in BIC of 13.79% points is in favor of the TCP‐coatings. However, the results are not statistically significant, in part due to the fact that the variability between the studies increased over time. The results of the HA group show a significant difference in mean BIC of 6.94% points after 14 days in favor of the reference surface. After 21–28 days and 42–84 days the difference in BIC is slightly in favor of the test group with 1.53% points and 1.57% points, respectively, lacking significance. In large animals, there does not seem to be much effect of TCP‐coated or HA‐coated implants over uncoated rough titanium implants in the short term.

The Effectiveness of Osseodensification Drilling Protocol for Implant Site Osteotomy: A Systematic Review of the Literature and Meta-Analysis.

Many different osteotomy procedures has been proposed in the literature for dental implant site preparation. The osseodensification is a drilling technique that has been proposed to improve the local bone quality and implant stability in poor density alveolar ridges. This technique determines an expansion of the implant site by increasing the density of the adjacent bone. The aim of the present investigation was to evaluate the effectiveness of the osseodensification technique for implant site preparation through a literature review and meta-analysis. The database electronic research was performed on PubMed (Medline) database for the screening of the scientific papers. A total of 16 articles have been identified suitable for the review and qualitative analysis—11 clinical studies (eight on animals, three on human subjects), four literature reviews, and one case report. The meta-analysis was performed to compare the bone-to-implant contact % (BIC), bone area fraction occupied % (BAFO), and insertion torque of clockwise and counter-clockwise osseodensification procedure in animal studies. The included articles reported a significant increase in the insertion torque of the implants positioned through the osseodensification protocol compared to the conventional drilling technique. Advantages of this new technique are important above all when the patient has a strong missing and/or low quantity of bone tissue. The data collected until the drafting of this paper detect an improvement when the osseodensification has been adopted if compared to the conventional technique. A significant difference in BIC and insertion torque between the clockwise and counter-clockwise osseodensification procedure was reported, with no difference in BAFO measurements between the two approaches. The effectiveness of the present study demonstrated that the osseodensification drilling protocol is a useful technique to obtain increased implant insertion torque and bone to implant contact (BIC) in vivo. Further randomized clinical studies are required to confirm these pieces of evidence in human studies.

Ridge alterations after implant placement in fresh extraction sockets or in healed crests: An experimental in vivo investigation.

To study the early and late bone healing around implants placed according to a flapless immediate (test) or flapped delayed (control) implant surgical protocol. In eight beagle dogs, immediate and delayed implants were placed. Test and control implants were randomly assigned, and horizontal and vertical bone remodelling, as well as bone-to-implant contact (BIC), were assessed with histology at 2 and 8weeks. Teeth were used as negative controls. Similar results were attained in the two groups when the vertical resorption of the buccal bone crest was evaluated (approximately 0.5mm). On the other hand, a marked horizontal buccal bone resorption was observed. Immediate implants attained a thinner buccal bone crest as compared to the delayed implant and the tooth. De novo bone formation on the implant surface appeared to be more pronounced at delayed sites at 2weeks, whereas at 8weeks, no difference in BIC was observed. Ridge alterations occurred at both implant placement protocols, with similar limited amounts of vertical buccal bone reduction and a pronounced horizontal bone reduction. The process of horizontal bone remodelling differed between the two surgical protocols.

Control Variable Implants Improve Interpretation of Surface Modification and Implant Design Effects on Early Bone Responses: An In Vivo Study

This in vivo study used control variable implants to compare early bone responses in fluoride-modified (F-mod) and hydrophilic, sandblasted, large-grit, acid-etched (modSLA) surface implants that differed in implant design. Four different types of implants (n = 24) were prepared: F-mod surface with Astra Tech implant design; modSLA surface with Straumann implant design; sandblasted, large-grit, acid-etched (SLA) surface with Astra Tech design; and SLA surface with Straumann implant design. Scanning electron microscopy, confocal laser scanning microscopy, and x-ray photoelectron spectroscopy were performed to assess implant surface characteristics. Four implants from each implant type were inserted in the tibiae of four rabbits that were sacrificed 10 days after surgery. Bone-to-implant contact (BIC) and bone area (BA) were measured to evaluate early bone responses. Analysis of variance with Tukey's multiple comparison method was used for the histomorphometric data to find any significant difference. The surface characteristic-related data were analyzed using the Kruskal-Wallis test. The level of significance was .05 in statistical analyses. No significant differences in BIC and BA were found among the modified surfaces (P > .05), whereas significant differences were found in surface topography and surface chemistry. The different designs showed no significant effects on early bone responses when identical surface modifications were applied (P > .05). F-mod and modSLA surfaces showed no significant differences in early bone responses. Furthermore, the implant design had no influence on the bone response. This in vivo experimental model will help improve the evaluation of surface modification factors by allowing an independent estimation of one variable (surface modification) against a constant (implant design).

Effect of Biologic Aging of Implants on Osseointegration in the Dog.

The objective of this preclinical study was to investigate the effect of biologic aging of implants on osseointegration in the canine. According to multiple comparisons, there was a significant difference in bone-to-implant contact (BIC) between control implants placed 6 months after manufacture and 2-week-old implants (P = .016), and between control and newly prepared implants with acid-etching (P = .019). However, there was no significant difference in BIC between newly prepared implants with acid-etching and 2-week-old implants. In all groups, BIC at 12 weeks was significantly higher than at week 4 (P < .05). There were no significant differences in bone volume (BV) regardless of area and time. Biologic aging of implants might affect osseointegration in the bone marrow zone at 4 weeks of healing. Although implant aging did not greatly affect BIC and BV at 12 weeks of healing in this study, further research is required to determine an appropriate period of biologic aging of implants that yields significant clinical effects.

Role of Osteogenic Coatings on Implant Surfaces in Promoting Bone-To-Implant Contact in Experimental Osteoporosis

The aim of this systematic review and meta-analysis was to evaluate the role of osteogenic coatings (placement of a thin film of organic and inorganic osteoinductive and osteoproliferative materials) on implant surfaces in augmenting bone-to-implant contact (BIC) in osteoporotic bone. To answer the focused question "Do osteogenic coatings on implant surfaces increase BIC in osteoporotic bone?" PubMed/MEDLINE, EMBASE, ISI Web of Knowledge, Scopus, and Google-Scholar databases were searched till June 2017 using different combinations of the following key words: bone-to-implant contact, coating, implant surface, osseointegration, and osteoporosis. Letters to the Editor, review articles, case-reports/case-series, and commentaries were excluded. Six animal studies were included, in which osteoporosis was induced by bilateral ovariectomy. In all studies, implant surface roughness was increased by various osteogenic surface coatings including alumina, hydroxyapatite, calcium phosphate, and zoledronic acid. Five studies showed that bone volume and BIC are significantly higher around implants with coated surfaces than noncoated implants. In 1 study, there was no difference in BIC around coated and noncoated implants. Although experimental studies have shown that osteogenic coatings are effective in enhancing BIC, their clinical relevance requires further investigations.

Bone Regeneration Using Adipose-Derived Stem Cells with Fibronectin in Dehiscence-Type Defects Associated with Dental Implants: An Experimental Study in a Dog Model.

To determine the bone regeneration potential of a ceramic biomaterial coated with fibronectin and adipose-derived stem cells covered in three-wall critical-size defects associated with dental implants. In a total of 18 dogs, four dehiscence-type and critical-size defects were created surgically in the edentulous alveolar ridge with the simultaneous placement of dental implants. Defects were randomly regenerated using biomaterials coated with particulate ß-tricalcium phosphate (β-TCP), β-TCP with fibronectin (Fn) (β-TCP-Fn), and β-TCP with a combination of Fn and autologous adipose-derived stem cells (ADSCs) (β-TCP-Fn-ADSCs), leaving one defect as the control. The animals were divided into three groups according to the time of euthanasia (1, 2, or 3 months). Statistically significant differences between the three study groups (β-TCP, β-TCP-Fn, β-TCP-Fn-ADSCs) and the control group in the total area of bone regeneration and mineralized and nonmineralized tissue at 1, 2, and 3 months of healing were not observed. At 2 months, defects treated with β-TCP-Fn-ADSCs showed a significant decrease in the percentage of bone-to-implant contact (BIC) as compared with the β-TCP-Fn (P = .041) and control (P = .012) groups. At 3 months of healing, however, significant differences in BIC between the three study groups and controls were not found (P = .388). The use of ADSCs in the bone regeneration processes of dehiscencetype defects associated with simultaneous implant insertion does not seem to improve the area of bone regeneration or the percentage of BIC compared with other biomaterials or the control alveolar defect.

The Effect of Osteotomy Dimension on Implant Insertion Torque, Healing Mode, and Osseointegration Indicators: A Study in Dogs.

This study investigated the effect of the osteotomy diameter for implant placement torque and its effect on the osseointegration. Eight male beagle dogs received 48 implants (3.75 mm × 10 mm) in their right and left radius, 3 implants per side and allowed to heal for 3 weeks. Three experimental groups were evaluated. Group 1: implant with an undersized osteotomy of 3.0 mm; group 2: osteotomy of 3.25 mm, and group 3: osteotomy of 3.5 mm. The insertion torque was recorded for all implants. Histological sectioning and histometric analysis were performed evaluating bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO). Implants of group 1 presented statistically higher insertion torque than those of groups 2 and 3 (P < 0.01). No differences in BIC or BAFO were observed between the groups. From a morphologic standpoint, substantial deviations in healing mode were observed between groups. Based on the present methodology, the experimental alterations of surgical technic can be clinically used with no detrimental effect over the osseointegration process.

Biomechanical and histologic basis of osseodensification drilling for endosteal implant placement in low density bone. An experimental study in sheep

A bone drilling concept, namely osseodensification, has been introduced for the placement of endosteal implants to increase primary stability through densification of the osteotomy walls. This study investigated the effect of osseodensification on the initial stability and early osseointegration of conical and parallel walled endosteal implants in low density bone. Five male sheep were used. Three implants were inserted in the ilium, bilaterally, totaling 30 implants (n=15 conical, and n=15 parallel). Each animal received 3 implants of each type, inserted into bone sites prepared as follows: (i) regular-drilling (R: 2mm pilot, 3.2mm, and 3.8mm twist drills), (ii) clockwise osseodensification (CW), and (iii) counterclockwise (CCW) osseodensification drilling with Densah Bur (Versah, Jackson, MI, USA): 2.0mm pilot, 2.8mm, and 3.8mm multi-fluted burs. Insertion torque as a function of implant type and drilling technique, revealed higher values for osseodensification relative to R-drilling, regardless of implant macrogeometry. A significantly higher bone-to-implant contact (BIC) for both osseodensification techniques (p<0.05) was observed compared to R-drilling. There was no statistical difference in BIC as a function of implant type (p=0.58), nor in bone-area-fraction occupancy (BAFO) as a function of drilling technique (p=0.22), but there were higher levels of BAFO for parallel than conic implants (p=0.001). Six weeks after surgery, new bone formation along with remodeling sites was observed for all groups. Bone chips in proximity with the implants were seldom observed in the R-drilling group, but commonly observed in the CW, and more frequently under the CCW osseodensification technique. In low-density bone, endosteal implants present higher insertion torque levels when placed in osseodensification drilling sites, with no osseointegration impairment compared to standard subtractive drilling methods.

Efficacy of Vitamin D3 Supplementation on Osseointegration of Implants

The aim was to systematically review the efficacy of vitamin D3 (VD3) supplementation on the osseointegration of implants. The addressed focused question was "does VD3 supplementation affect osseointegration around implants?" Indexed databases were searched from 1969 up to and including March 2015 using various key words including: "Bone to implant contact"; "implant"; "vitamin D"; and "osseointegration." Letters to the editor, case reports/case series, reviews, and articles published in languages other than English were excluded. The pattern of the present systematic review was customized to primarily summarize the pertinent data. Six experimental studies (4 in rodents and 2 in rabbits) were included. Number of titanium implants placed ranged between 28 and 100 implants. Results from 5 studies showed that VD3 supplementation enhanced new bone formation and/or bone to implant contact (BIC) around implants. One study showed no significant difference in BIC and new bone formation around VD3 coated and noncoated implants. One study reported that insulin therapy with adjunct VD3 supplementation enhances new bone formation around implants in diabetic rats than when insulin replacement therapy is used alone. Efficacy of VD3 supplementation on osseointegration of implants remains controversial and requires further investigations.

Significance of osteogenic surface coatings on implants to enhance osseointegration under osteoporotic-like conditions.

The aim was to assess the significance of osteogenic surface coatings on implants to enhance osseointegration under osteoporotic-like (OP-like) conditions. To address the focused question "Do osteogenic surface coatings on implants enhance osseointegration under OP-like conditions?" PubMed/MEDLINE and Google-Scholar databases were searched from 1995 up to and including February 2014 using various keywords. Unpublished data, letters to the editor, review articles, and articles published in languages other than English were excluded. Of the 28 studies identified, 11 experimental studies were included. These studies were performed on bilaterally ovariectomized animals. In all studies, implant surface roughness was increased by various osteogenetic surface coatings including alumina, hydroxyapatite, calcium phosphate, and zoledronic acid. Nine studies reported that compared with non-coated surfaces, osteogenic coatings on implant surfaces increases bone volume and bone-to-implant contact (BIC) under OP-like conditions. In 2 studies, there was no difference in BIC around hydroxyapatite-coated implants placed in animals with and without OP-like conditions. Osteogenic coatings on implant surfaces enhanced osseointegration in animals with OP-like conditions. However, additional clinical studies are warranted to assess the role of osteogenic coatings in increasing osseointegration in patients with osteoporosis.

Integration of fluoridated implants in onlay autogenous bone grafts – An experimental study in the rabbit tibia

IntroductionBone augmentation before treatment with endosseous implants is a common procedure for rehabilitation of the edentulous jaw. Both machined and surface modified implants have been used in one-stage and two-stage surgery protocols with varying results and survival rates. The influence of surface modification on the integration of implants has been documented in both non-grafted and grafted bone. The aim of this study was to compare the integration and stability of surface modified fluoridated vs. machined implants when placed simultaneously with an onlay bone graft. Material and methodsEight rabbits were used in this study. A disc shaped bone graft was harvested from each side of the sagittal suture of the calvarial bone and fixed bi-cortically to the proximal tibial metaphysis by means of a dental implant, 9 mm long and 3.5 mm in diameter with a smooth machined surface as control and a blasted, fluoridated surface as test. Test and control sides were randomised. After a healing time of 8 weeks, the rabbits were sacrificed and the implants were removed en block for light microscopic analysis. Bone to implant contact (BIC) was registered as well as the amount of bone filling a rectangle indicating a region of interest (ROI) in the grafted area. Resonance frequency analysis (RFA) was conducted both at the time of surgery and at the end of the study. ResultsOur results showed statistically significant differences in BIC within the grafted area and the total bone to implant contact between the test and control sides in favour of the surface modified implants. The bone area filling the threads within a region of interest showed no statistically significant difference between the test and control sides. RFA showed higher implant stability with significant differences at the time of sacrifice in favour of the fluoridated implants. ConclusionSurface modified fluoridated implants showed a higher degree of osseointegration and stability in onlay bone grafts compared with control implants with machined surface texture.

The Effect of Simplifying Dental Implant Drilling Sequence on Osseointegration: An Experimental Study in Dogs

Objectives. To test the hypothesis that there would be no differences in osseointegration by reducing the number of drills for site preparation relative to conventional drilling sequence. Methods. Seventy-two implants were bilaterally placed in the tibia of 18 beagle dogs and remained for 1, 3, and 5 weeks. Thirty-six implants were 3.75 mm in diameter and the other 36 were 4.2 mm. Half of the implants of each diameter were placed under a simplified technique (pilot drill + final diameter drill) and the other half were placed under conventional drilling where multiple drills of increasing diameter were utilized. After euthanisation, the bone-implant samples were processed and referred to histological analysis. Bone-to-implant contact (BIC) and bone-area-fraction occupancy (BAFO) were assessed. Statistical analyses were performed by GLM ANOVA at 95% level of significance considering implant diameter, time in vivo, and drilling procedure as independent variables and BIC and BAFO as the dependent variables. Results. Both techniques led to implant integration. No differences in BIC and BAFO were observed between drilling procedures as time elapsed in vivo. Conclusions. The simplified drilling protocol presented comparable osseointegration outcomes to the conventional protocol, which proved the initial hypothesis.

Nano-crystalline diamond-coated titanium dental implants – A histomorphometric study in adult domestic pigs

Promising biomaterial characteristics of diamond-coatings in biomedicine have been described in the literature. However, there is a lack of knowledge about implant osseointegration of this surface modification compared to the currently used sandblasted acid-etched Ti-Al6-V4 implants. The aim of this study was to investigate the osseointegration of microwave plasma-chemical-vapour deposition (MWP-CVD) diamond-coated Ti-Al6-V4 dental implants after healing periods of 2 and 5 months.Twenty-four MWP-CVD diamond-coated and 24 un-coated dental titanium-alloy implants (Ankylos®) were placed in the frontal skull of eight adult domestic pigs. To evaluate the effects of the nano-structured surfaces on bone formation, a histomorphometric analysis was performed after 2 and 5 months of implant healing. Histomorphometry analysed the bone-to-implant contact (BIC). No significant difference in BIC for the diamond-coated implants in comparison to reference implants could be observed for both healing periods. Scanning electron microscopy revealed an adequate interface between the bone and the diamond surface. No delamination or particle-dissociation due to shearing forces could be detected. In this study, diamond-coated dental titanium-alloy implants and sandblasted acid-etched implants showed a comparable degree of osseointegration.

Section plane selection influences the results of histomorphometric studies: the example of dental implants.

This study was designed to determine and statistically analyze bone-to-implant contact (BIC) values for human specimens segmented in at least two different locations. Samples of human bone with fractured osseointegrated implants were obtained from six patients. Sections were prepared, dehydrated, and resin infiltrated. Undecalcified bone sections were produced using the thin-section technique according to Donath, ultimately obtaining a section thickness of approximately 20 μm. Fifteen specimens were available for histomorphometry. The bone sections were digitized and analyzed. The bone-to-metal contact (BMC) parameter was determined histomorphometrically. The BMC was returned in terms of the visibly bone-covered implant surfaces as a percentage of the total implant surface shown. The values obtained for the six implants were arranged as six maximum-distance pairs and tested for significance using the t-test for dependent samples. The mean difference in BIC was 11.69±9.79%. The two-sided test showed a significant difference (p=0.033). The accidental or deliberate choice of section plane for a bone-implant block has an influence on the BIC value. To make BIC values more comparable, a standardization of section planes is desirable.

Thin Bioactive Ceramic‐Coated Alumina‐Blasted/Acid‐Etched Implant Surface Enhances Biomechanical Fixation of Implants: An Experimental Study in Dogs

Thin bioceramic coatings have been regarded as potential substitutes for plasma-sprayed hydroxyapatite coatings. This study tested the hypothesis that a thin bioactive ceramic coating deposition on an alumina-blasted/acid-etched (AB/AE) surface would positively affect the biomechanical fixation and bone-to-implant contact (BIC) of plateau root form implants. Implants of two different lengths (i.e., 4.5 × 11 mm long, n = 36) and 4.5 × 6 mm (short, n = 36) and two different surfaces, that is, control (AB/AE) and test (AB/AE + 300 - 500 nm bioactive ceramic coating), were placed in the proximal tibiae of six beagle dogs. The implants were retrieved for analyses 2 and 4 weeks after placement. The implants in bone specimens were subjected to torque loads until a 10% drop of the maximum torque was recorded. The specimens were evaluated under optical microscopy for bone morphology and percent BIC. Statistical analysis was performed by a generalized linear mixed effects analysis of variance model and statistical significance set at p < 0.05. Significantly higher torque-to-interface fracture levels for test surface groups of both lengths when compared to control surfaces were observed. No significant difference in BIC was observed between test and control implants of equal length. Histomorphological analysis showed higher degrees of bone organization between the plateaus of test implant surfaces at both implantation times. Because the presence of a thin bioactive ceramic coating on the surface did not affect BIC, but positively affected implant biomechanical fixation, the hypothesis was partially validated.

Evaluation of a nanometer roughness scale resorbable media-processed surface: a study in dogs

This study compared the biomechanical fixation and bone-to-implant contact (BIC) of implants with different surfaces treatment (experimental - resorbable blasting media-processed nanometer roughness scale surface, and control - dual acid-etched) in a dog model. Surface characterization was made in six implants by means of scanning electron microscopic imaging, atomic force microscopy to evaluate roughness parameters, and X-ray photoelectron spectroscopy (XPS) for chemical assessment. The animal model comprised the bilateral placement of control (n=24) and experimental surface (n=24) implants along the proximal tibiae of six mongrel dogs, which remained in place for 2 or 4 weeks. Half of the specimens were biomechanically tested (torque), and the other half was subjected to histomorphologic/morphometric evaluation. BIC and resistance to failure measures were each evaluated as a function of time and surface treatment in a mixed model ANOVA. Surface texturing was significantly higher for the experimental compared with the control surface. The survey XPS spectra detected O, C, Al, and Ti at the control group, and Ca (∼0.2- 0.9%) and P (∼1.7- 4.1%) besides O, C, Al, and Ti at experimental surfaces. While no statistical difference in BIC was found between experimental and control surfaces or between 2 and 4 weeks in vivo, both longer time and use of experimental surface significantly increased resistance to failure. The experimental surface resulted in enhanced biomechanical fixation but comparable BIC relative to control, suggesting higher bone mechanical properties around the experimental implants.

Early Bone Healing around Different Implant Bulk Designs and Surgical Techniques: A Study in Dogs

To evaluate the bone healing response to different implant root shape designs in a dog model. Three by eight millimeter screw-type short-pitch (SP) and large-pitch (LP) implants (Intra-Lock International, Boca Raton, FL, USA), and 4.5 x 6 mm plateau (P) implants (Bicon LLC, Boston, MA, USA) were placed along the proximal tibia of six dogs for 2 and 4 weeks. The combination of implant design and final osteotomy drilling resulted in healing chambers for the LP and P implants. The implants were nondecalcified processed to plates of approximately 30-microm thickness and were evaluated by optical microscopy for healing patterns and bone-to-implant contact (BIC). One-way analysis of variance at 95% level of significance and Tukey's test were utilized for multiple comparisons among the groups' BIC. Microscopy showed a approximately 150-microm region of newly deposited bone along the whole perimeter of SP implants, near the edge of the LP implant threads, and plateau tips for P implants. Rapid woven bone formation and filling was observed in regions where surgery and implant design resulted in healing chambers. No significant differences in BIC were observed (p > .75). Different implant design/surgical protocol resulted in varied bone healing patterns. However, the BIC and bone morphology evolution between implant designs were comparable. Regardless of the combination between implant design and final osteotomy drilling, bone morphology evolution from 2 to 4 weeks was comparable.

Histomorphometric Evaluation of a Nanothickness Bioceramic Deposition on Endosseous Implants: A Study in Dogs

The objective of this study was to evaluate the bone response to a nanothickness bioceramic ion beam-assisted deposition (IBAD) on endosteal implants in a canine model. Alumina-blasted/acid-etched (control) and IBAD-modified (test) implants were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy + ion beam milling, thin-film mode X-ray diffraction, and atomic force microscope. The implants were surgically placed in four dogs' proximal tibiae and remained for 2 and 4 weeks in vivo. Oxytetracycline (10 mg/kg) was administered for bone labeling 48 hours prior to euthanization. Following euthanization, nondecalcified thin sections were prepared for UV and transmitted light microscopy. The amount of bone labeling was evaluated along the length and away from the implant surface by means of a computer software. The % bone-to-implant contact (BIC) was determined for each specimen. One-way analysis of variance at 95% level of significance along with Tukey's post hoc multiple comparisons were utilized for statistical evaluation. The characterization showed Ca- and P-based amorphous coatings with a 20- to 50-nm thickness. In vivo results showed a significant increase in general and site-specific (to 0.5 mm from the implant surface) bone activity for the 4-week test implants compared with the control implants. Bone activity levels decreased as a function of distance from the implant surface for all groups. No significant differences in BIC were observed between groups. This study showed that both surfaces were biocompatible and osteoconductive and that a time-dependent increase in osteoactivity occurred around the test implants.