The purpose of the study was to evaluate histologically, whether vertical bone augmentation can be achieved using a hollow ceramic space maintaining device in a rabbit calvaria model. Furthermore, the chemistry of microporous hydroxyapatite and zirconia were tested to determine which of these two ceramics are most suitable for guided bone generation. 24 hollow domes in two different ceramic materials were placed subperiosteal on rabbit skull bone. The rabbits were sacrificed after 12 weeks and the histology results were analyzed regarding bone-to-material contact and volume of newly formed bone. The results suggest that the effect of the microporous structure of hydroxyapatite seems to facilitate for the bone cells to adhere to the material and that zirconia enhance a slightly larger volume of newly formed bone. In conclusion, the results of the current study demonstrated that ceramic space maintaining devices permits new bone formation and osteoconduction within the dome.
hydroxyapatite; zirconia; guided bone regeneration; GBR; histology; membrane
This study aims to evaluate bone response to an implant surface modified by 1α,25-dihydroxyvitamin D3 [1.25-(OH)2D3] in vivo and the potential link between 1.25-(OH) 2D3 surface concentration and bone response.
Material and Methods
Twenty-eight implants were divided into 4 groups (1 uncoated control, 3 groups coated with 1.25-(OH)2D3 in concentrations of 10-8, 10-7 and 10-6 M respectively), placed in the rabbit tibia for 6 weeks. Topographical analyses were carried out on coated and uncoated discs using interferometer and atomic-force-microscope (AFM). Twenty-eight implants were histologically observed (bone-to-implant-contact [BIC] and new-bone-area [NBA]).
The results showed that the 1.25-(OH)2D3 coated implants presented a tendency to osseointegrate better than the non-coated surfaces, the differences were not significant (P > 0.05).
The effect of 1.25-(OH)2D3 coating to implants suggested possible dose dependent effects, however no statistical differences could be found. It is thought that the base substrate topography (turned) could not sustain sufficient amount of 1.25-(OH)2D3 enough to present significant biologic responses. Thus, development a base substrate that can sustain 1.25-(OH)2D3 for a long period is necessary in future studies.
dental implants; vitamin D; drug dose response relationship; histological techniques; bone formation
Polyether ether ketone (PEEK) is today frequently used as a biomaterial in different medical operations due to its excellent mechanical and chemical properties. However, the untreated surface of PEEK is bioinert and hydrophobic, and it does not osseointegrate in its pure form. The aim of this study was to evaluate a unique nano-modified surface of PEEK with respect to osseointegration. Forty-eight threaded, non-cutting PEEK implants were inserted bilaterally in the tibia of 24 rabbits. Half of the implants (n=24) were coated with nanocrystalline hydroxyapatite (test) and the remaining implants (n=24) were left uncoated (control). Half of the animals (n=12) were euthanized after 3 weeks of healing and the remaining (n=12) after 12 weeks. The implant retention was measured with a removal torque apparatus. Surface analysis was performed with interferometry, scanning electron microscopy, and X-ray photon spectroscopy to relate the removal torque to the applied surface. The test implants revealed a significantly higher retention after 3 weeks (P=0.05) and 12 weeks (P=0.028) compared to controls. The result of the present study proves that the addition of nanocrystalline hydroxyapatite coating to PEEK surfaces significantly increases its removal torque and biocompatibility.
polyether ether ketone; hydroxyapatite; removal torque; nanotopography
The aim of this study was to test the null hypothesis of no difference in the implant failure rates, postoperative infection, and marginal bone loss for patients being rehabilitated by dental implants being inserted by a flapless surgical procedure versus the open flap technique, against the alternative hypothesis of a difference. An electronic search without time or language restrictions was undertaken in March 2014. Eligibility criteria included clinical human studies, either randomized or not. The search strategy resulted in 23 publications. The I2 statistic was used to express the percentage of the total variation across studies due to heterogeneity. The inverse variance method was used for random-effects model or fixed-effects model, when indicated. The estimates of relative effect were expressed in risk ratio (RR) and mean difference (MD) in millimeters. Sixteen studies were judged to be at high risk of bias, whereas two studies were considered of moderate risk of bias, and five studies of low risk of bias. The funnel plots indicated absence of publication bias for the three outcomes analyzed. The test for overall effect showed that the difference between the procedures (flapless vs. open flap surgery) significantly affect the implant failure rates (P = 0.03), with a RR of 1.75 (95% CI 1.07–2.86). However, a sensitivity analysis revealed differences when studies of high and low risk of bias were pooled separately. Thus, the results must be interpreted carefully. No apparent significant effects of flapless technique on the occurrence of postoperative infection (P = 0.96; RR 0.96, 95% CI 0.23–4.03) or on the marginal bone loss (P = 0.16; MD −0.07 mm, 95% CI −0.16–0.03) were observed.
This study aimed at investigating if a coating of hydroxyapatite nanocrystals would enhance bone healing over time in trabecular bone. Sandblasted and acid etched titanium implants with and without a submicron thick coat of hydroxyapatite nanocrystals (nano-HA) were implanted in rabbit femur with healing times of 2, 4, and 9 weeks. Removal torque analyses and histological evaluations were performed. The torque analysis did not show any significant differences between the implants at any healing time. The control implant showed a tendency of more newly formed bone after 4 weeks of healing and significantly higher bone area values after 9 weeks of healing. According to the results from this present study, both control and nano-HA surfaces were biocompatible and osteoconductive. A submicron thick coating of hydroxyapatite nanocrystals deposited onto blasted and acid etched screw shaped titanium implants did not enhance bone healing, as compared to blasted and etched control implants when placed in trabecular bone.
The aim of this study was to assess histologically and histomorphometrically the early bone forming properties after 3 weeks for 2 commercially available implants, one supposedly possessing nanotopography and one without, in a rabbit femur model. Twenty-four implants divided equally into 2 groups were utilized in this study. The first group (P-I MICRO+NANO) was a titanium oxide (TiO2) microblasted and noble gas ion bombarded surface while the second group (Ospol) was anodic oxidized surface with calcium and phosphate incorporation. The implants were placed in the rabbit femur unicortically and were allowed to heal for 3 weeks. After euthanasia, the samples were subjected to histologic sectioning and bone-implant contact and bone area were evaluated histomorphometrically under an optical microscope. The histomorphometric evaluation presented that the P-I MICRO+NANO implants demonstrated significantly higher new bone formation as compared to the Ospol implants. Within the limitations of this study, the results suggested that nanostructures presented significantly higher bone formation after 3 weeks in vivo, and the effect of chemistry was limited, which is indicative that nanotopography is effective at early healing periods.
Aim. This study aimed to observe the morphological and molecular effect of laminin-1 doping to nanostructured implant surfaces in a rabbit model. Materials and Methods. Nanostructured implants were coated with laminin-1 (test; dilution, 100 μg/mL) and inserted into the rabbit tibiae. Noncoated implants were used as controls. After 2 weeks of healing, the implants were removed and subjected to morphological analysis using scanning electron microscopy (SEM) and gene expression analysis using the real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Results. SEM revealed bony tissue attachment for both control and test implants. Real-time RT-PCR analysis showed that the expression of osteoblast markers RUNX-2, osteocalcin, alkaline phosphatase, and collagen I was higher (1.62-fold, 1.53-fold, 1.97-fold, and 1.04-fold, resp.) for the implants modified by laminin-1 relative to the control. All osteoclast markers investigated in the study presented higher expression on the test implants than controls as follows: tartrate-resistant acid phosphatase (1.67-fold), calcitonin receptor (1.35-fold), and ATPase (1.25-fold). The test implants demonstrated higher expression of inflammatory markers interleukin-10 (1.53-fold) and tumour necrosis factor-α (1.61-fold) relative to controls. Conclusion. The protein-doped surface showed higher gene expression of typical genes involved in the osseointegration cascade than the control surface.
The aim of this study was to evaluate the early bone response around laminin-1-coated titanium implants. Forty-five rats distributed in three equally sized groups were provided with one control (turned) and one test (laminin-1-coated) implant and were sacrificed after 3, 7, and 21 days. Real-time reverse-transcriptase polymerase chain reaction was performed for osteoblast markers (alkaline phosphatase, runt-related transcription factor 2, osteocalcin, type I collagen, and bone morphogenic protein 2), osteoclast markers (cathepsin K and tartrate-resistant acid phosphatase), inflammation markers (tumor necrosis factor α, interleukin 1β and interleukin 10), and integrin β1. Bone implant contact (BIC) and bone area (BA) were assessed and compared to the gene expression. After 3 days, the expression of bone markers was higher for the control group. After 7 days, the expression of integrin β1 and osteogenic markers was enhanced for the test group, while cathepsin K and inflammation markers were down-regulated. No significant differences in BIC or BA were detected between test and control at any time point. As a conclusion, implant coating with laminin-1 altered gene expression in the bone-implant interface. However, traditional evaluation methods, as histomorphometry, were not adequately sensitive to detect such changes due to the short follow-up time.
An important parameter for the clinical success of dental implants is the formation
of direct contact between the implant and surrounding bone, whose quality is directly
influenced by the implant surface roughness. A screw-shaped design and a surface with
an average roughness of Sa of 1-2 µm showed a better result. The combination of
blasting and etching has been a commonly used surface treatment technique. The
versatility of this type of treatment allows for a wide variation in the procedures
in order to obtain the desired roughness.
To compare the roughness values and morphological characteristics of 04 brands of
implants, using the same type of surface treatment. In addition, to compare the
results among brands, in order to assess whether the type of treatment determines
the values and the characteristics of implant surface roughness.
Material and methods
Three implants were purchased directly from each selected company in the market,
i.e., 03 Brazilian companies (Biomet 3i of Brazil, Neodent and Titaniumfix) and 01
Korean company (Oneplant). The quantitative or numerical characterization of the
roughness was performed using an interferometer. The qualitative analysis of the
surface topography obtained with the treatment was analyzed using scanning
electron microscopy images.
The evaluated implants showed a significant variation in roughness values: Sa for
Oneplant was 1.01 µm; Titaniumfix reached 0.90 µm; implants from Neodent 0.67 µm,
and Biomet 3i of Brazil 0.53 µm. Moreover, the SEM images showed very different
patterns for the surfaces examined.
The surface treatment alone is not able to determine the roughness values and
Surface treatments; Blasting; Acid etched; Dental implants; Osseointegration
The objective of this study was to investigate the effect of a laminin
coating on calcium phosphate precipitation on three potentially bioactive
titanium surfaces in simulated body fluid.
Material and Methods
Blasted titanium discs were prepared by alkali and heat treatment (AH),
anodic oxidation (AO) or hydroxyapatite coating (HA) and subsequently coated
with laminin. A laminin coated blasted surface (B) served as a positive
control while a blasted non coated (B-) served as a negative control.
Surface morphology was examined by Scanning Electron Microscopy (SEM). The
analysis of the precipitated calcium and phosphorous was performed by Energy
Dispersive X-ray Spectroscopy (EDX).
The thickness of the laminin coating was estimated at 26 Å by ellipsometry.
Interferometry revealed that the coating process did not affect any of the
tested topographical parameters on µm level when comparing B to B-. After 2
weeks of incubation in SBF, the alkali-heat treated discs displayed the
highest calcium phosphate deposition and the B group showed higher levels of
calcium phosphate than the B- group.
Our results suggest that laminin may have the potential to be used as a
coating agent in order to enhance the osseoinductive performance of
biomaterial surfaces, with the protein molecules possibly functioning as
nucleation centres for apatite formation. Nevertheless, in vivo studies are
required in order to clarify the longevity of the coating and its
performance in the complex biological environment.
laminin; titanium; biomaterials; calcium phosphates; dental implants; osseointegration.
Implant placement in molar extraction sockets can be difficult due to complex
multi-root anatomy and the lack of predictable primary stability. The aim of
this study was to evaluate the outcome of an 8 - 9 mm diameter tapered
implant, designed to be placed in molar extraction sockets.
Material and methods
Patients treated at least 1 year before with a Max® implant (Southern
Implants, Irene, South Africa) were invited for a clinical examination.
Variables collected were surgical and prosthetic protocol, implant dimension
and smoking habits. Peri-implant bone level was determined on peri-apical
radiographs and compared to baseline, being implant insertion.
98 implants had been placed in 89 patients. One implant had failed. Thirty
eight patients representing 47 implants (maxilla 26, mandible 21) were
available for clinical examination. Mean bone loss was 0.38 mm (SD 0.48;
range - 0.50 – 1.95) after a mean follow-up of 20 months (range 12 - 35).
Implant success was 97.9%. Around 30 implants, a bone substitute was used to
fill the residual space, but this did not affect the bone loss outcome. Bone
loss was only significantly different between maxilla and mandible (0.48 mm
vs. 0.27 mm) and between the 8 and 9 mm diameter implants (0.23 mm vs. 0.55
mm). A full papilla was present at 71% of the interproximal sites and
irrespective of bone loss.
The Max® implant demonstrated good primary stability, when placed in molar
extraction sockets, with limited bone loss over time.
dental implants; endosseous dental implantation; single-tooth dental implants; implant-supported dental prosthesis; tooth socket; bone grafting.
The aim of the present study was to evaluate calcium phosphate precipitation
and the amount of precipitated protein on three potentially bioactive
surfaces when adding laminin in simulated body fluid.
Material and Methods
Blasted titanium discs were prepared by three different techniques claimed to
provide bioactivity: alkali and heat treatment (AH), anodic oxidation (AO)
or hydroxyapatite coating (HA). A blasted surface incubated in
laminin-containing simulated body fuid served as a positive control (B)
while a blasted surface incubated in non laminin-containing simulated body
fuid served as a negative control (B-). The immersion time was 1 hour, 24
hours, 72 hours and 1 week. Surface topography was investigated by
interferometry and morphology by Scanning Electron Microscopy (SEM).
Analysis of the precipitated calcium and phosphorous was performed by Energy
Dispersive X-ray Spectroscopy (EDX) and the adsorbed laminin was quantified
by iodine (125I) labeling.
SEM demonstrated that all specimens except for the negative control were
totally covered with calcium phosphate (CaP) after 1 week. EDX revealed that
B- demonstrated lower sum of Ca and P levels compared to the other groups
after 1 week. Iodine labeling demonstrated that laminin precipitated in a
similar manner on the possibly bioactive surfaces as on the positive control
Our results indicate that laminin precipitates equally on all tested titanium
surfaces and may function as a nucleation center thus locally elevating the
calcium concentration. Nevertheless further studies are required to clarify
the role of laminin in the interaction of biomaterials with the host bone
laminin; titanium; body fluid; calcium phosphates; biomaterials.
This review summarizes the present documentation for the SLActive surface, a hydrophilic and nanostructured surface produced by Straumann Company in Switzerland, and covers the results from 15 in vitro, 17 in vivo, and 16 clinical studies. The SLActive surface is a development of the large grit-blasted and acid-etched SLA surface, and is further processed to a high degree of hydrophilicity. In general, the in vitro and in vivo studies of the SLActive surface demonstrate a stronger cell and bone tissue response than for the predecessor, the SLA surface, produced by the same company. However, in most studies, this difference disappears after 6–8 weeks. In the clinical studies, a stronger bone response was reported for the SLActive surface during the early healing phase when compared with the SLA surface. However, the later biological response was quite similar for the two surfaces and both demonstrated very good clinical results.
SLActive; surface; in vitro; in vivo; clinical results
The soft tissue around dental implants forms a barrier between the oral environment and the peri-implant bone and a crucial factor for long-term success of therapy is development of a good abutment/soft-tissue seal. Sol-gel derived nanoporous TiO2 coatings have been shown to enhance soft-tissue attachment but their effect on adhesion and biofilm formation by oral bacteria is unknown.
We have investigated how the properties of surfaces that may be used on abutments: turned titanium, sol-gel nanoporous TiO2 coated surfaces and anodized Ca2+ modified surfaces, affect biofilm formation by two early colonizers of the oral cavity: Streptococcus sanguinis and Actinomyces naeslundii. The bacteria were detected using 16S rRNA fluorescence in situ hybridization together with confocal laser scanning microscopy.
Interferometry and atomic force microscopy revealed all the surfaces to be smooth (Sa ≤ 0.22 μm). Incubation with a consortium of S. sanguinis and A. naeslundii showed no differences in adhesion between the surfaces over 2 hours. After 14 hours, the level of biofilm growth was low and again, no differences between the surfaces were seen. The presence of saliva increased the biofilm biovolume of S. sanguinis and A. naeslundii ten-fold compared to when saliva was absent and this was due to increased adhesion rather than biofilm growth.
Nano-topographical modification of smooth titanium surfaces had no effect on adhesion or early biofilm formation by S. sanguinis and A. naeslundii as compared to turned surfaces or those treated with anodic oxidation in the presence of Ca2+. The presence of saliva led to a significantly greater biofilm biovolume but no significant differences were seen between the test surfaces. These data thus suggest that modification with sol-gel derived nanoporous TiO2, which has been shown to improve osseointegration and soft-tissue healing in vivo, does not cause greater biofilm formation by the two oral commensal species tested than the other surfaces.