Ion implantation: surface treatment for improving the bone integration of titanium and Ti6Al4V dental implants

Dental implants subjected to surface treatment have shown better bone integration than implants which have only been turned (machined). Three main types of treatment are presently available: the addition of material or coating, the removal of material, and surface modification. Ion implantation corresponds to the third approach. A histomorphometric study is made following the rabbit tibial bone placement of 88 commercial dental implants of pure titanium and Ti6AI4V subjected to surface treatment in the form of different ion implants (C+, CO+, N+, Ne+). Light microscopic, scanning electron microscopic (SEM), electron microsonde (EDS) and X-ray photoelectron spectroscopy (XPS) studies were made. The results indicate improved bone integration (expressed as percentage bone-implant contact) in those specimens subjected to ion implantation versus the non-treated controls, the difference being statistically significant for the groups treated with C+ and CO+. In these groups, XPS showed a Ti-O-C junction (bone-implant interface) involving covalent type bonds, these being stronger and more stable than the ion-type bonds usually established between the titanium oxide and bone.     

Histomorphometric study of ion implantation and diamond-like carbon as dental implant surface treatments in beagle dogs

PURPOSE: Improvements in the bone-implant interface can provide clinical benefits, such as increasing the amount of bone in contact with the implant and shortening the time required to achieve sufficient bone appositioning to allow early prosthetic loading. The present study describes the results obtained with 2 new surface treatments: (a) CO ion implantation; and (b) diamond-like carbon (DLC) coating. MATERIALS AND METHODS: Each group (ion implantation, DLC, and the control group, turned titanium) consisted of 12 samples. Beagle dogs subjected to previous partial edentulation were used. Dual histologic evaluation was made of percentage bone-implant contact (% BIC) of all samples based on conventional histomorphometric analysis and environmental scanning electron microscopy (ESEM). RESULTS: The results obtained after 3 and 6 months of dental implant placement showed greater and faster bone integration in the CO ion implantation group (61% and 62% BIC, respectively) compared with the DLC group (47% and 50%); the data corresponding to the ion implanted samples were statistically significant compared with the control group (33% and 49% BIC after 3 and 6 months, respectively). CONCLUSIONS: The results showed improved % BIC for implants with ion-implanted surfaces in comparison to DLC coating and machined controls. Furthermore, bone integration appeared to be accelerated in the ion implantation group, since high % BIC values were recorded in the early stages after in vivo implantation.     

Improvement of osseointegration of titanium dental implant surfaces modified with CO ions: a comparative histomorphometric study in beagle dogs

The aim of this study was to compare carbon-oxygen (CO) ion implantation as a surface treatment with diamond-like carbon and commercially treated implants, including double acid-etched (Osseotite), oxidized (TiUnite) and sandblasted and acid-etched (SLA), using machine-turned titanium implants as control. A total of 72 dental implants divided into 6 groups were placed in the mandibles of 12 beagle dogs. Evaluation was performed by conventional light transmission microscopy and environmental scanning electron microscopy (ESEM). The histological results obtained via ESEM demonstrated bone-implant contact percentage (%BIC) for implants treated with CO ion implantation of 61% and 62% at 3 and 6 months, respectively. At the same time points, the values were 48% and 45% for double acid-etched, 46% and 52% for sandblasted and acid-etched, 55% and 46% for oxidized, and 33% and 49% for machine-turned titanium control implants. Values of %BIC were statistically significantly higher in implants treated with CO ion implantation compared to the commercially treated implant group (p=0.002 and p=0.025) and the control implants (p=0.001 and p=0.032) at 3 and 6 months, respectively. No significant differences were observed between the three groups of commercially treated implants. The larger %BIC of the ion-implanted group was observable at an early stage.     

Microflora associated with successful and failed orthodontic mini-implants

Objectives: Mini-implants are used for orthodontic bone anchorage. The reasons for a potential instability or loss of the mini-implants during treatment are multiple. Among other factors, colonization of implants with pathogenic bacteria is discussed. Therefore, the microflora associated with successful and failed mini-implants has been screened.
Material and methods: A total of 76 mini-implants collected from 25 patients were observed during regular orthodontic treatment. Bacterial samples of eight failed and – exemplarily – four successful (control) cases were subjected to a universal Bacteria -directed real-time quantitative polymerase chain reaction for quantification in combination with a microarray-based identification of 20 selected species.
Results: The failure rate in the present investigation was 10.5%. The bacterial analysis did not reveal any major difference in the total amount or species composition between control and failed mini-implants. However, Actinomyces viscosus was found in four (100%) and Campylobacter gracilis in three (75%) stable controls, whereas both species were rarely found (12.5%) in failed implants.
Conclusions: In the present study, the peri-implant sulcus surrounding failed orthodontic mini-implants did not show a specific aggressive bacterial flora.     

Improved retention and bone-tolmplant contact with fluoride-modified titanium implants

PURPOSE: The purpose of the present study was to investigate whether a fluoride modification of the titanium surface would have an effect on bone response after implantation. MATERIALS AND METHODS: Titanium-oxide-blasted titanium implants with and without fluoride modification were investigated in a rabbit tibia model. Quantitative analysis of surface roughness, biomechanical interlocking, and in vivo tissue reactions in rabbit bone at 1 and 3 months after placement were compared. RESULTS: The fluoride-modified test implants had a slightly smoother surface (Sa: 0.91 +/- 0.14 microm) than the unmodified control implants (Sa: 1.12 +/- 0.24 microm). Significantly higher removal torque values (85 +/- 16 Ncm vs 54 +/- 12 Ncm) and shear strength between bone and implants (23 +/- 9 N/mm2 vs 15 +/- 5 N/mm2) were measured for the fluoride-modified implants after 3 months. The histomorphometric evaluations demonstrated higher bone-to-implant contact for test implants at 1 month (35% +/- 14% vs 26% +/- 8%) and 3 months (39% +/- 11% vs 31% +/- 6%) after placement. DISCUSSION: Implant surface modification with fluoride may result in morphologic and physiochemical phenomena that are of significance for the bone response. Another possible explanation for the findings in the present study is that a surface modification changes the surface chemical structures to be more suitable for bone bonding. CONCLUSION: Based on the biomechanical and histomorphometric data, the fluoride-modified titanium implants demonstrated a firmer bone anchorage than the unmodified titanium implants. These implants achieved greater bone integration than unmodified titanium implants after a shorter healing time.     

Mini-implants to reconstruct missing teeth in severe ridge deficiency and small interdental space: a 5-year case series

Two of the major obstacles for dental implant placement to replace missing teeth are the lack of adequate bone width and interdental space. Overcoming these limitations requires bone augmentation procedures that transform the deficient ridge into a ridge that is capable of receiving conventional tooth-form implants. In the case of inadequate interdental space, orthodontic tooth movement is advocated before implantation. Using narrow-diameter mini-implants allows the clinician to overcome both of these obstacles without the need for additional grafting procedures or orthodontic tooth movement. The mini-implants are immediately loaded and restored so as to enable the patient to have satisfactory mastication and aesthetic appearance. A 5-year follow up of 32 implants demonstrates the benefit of this treatment modality.     

The application of mini-implants for orthodontic anchorage

The aim of this study was to explore the use of mini-implants for skeletal anchorage, and to assess their stability and the causes of failure. Forty-five mini-implants were used in orthodontic treatment. The diameter of the implants was 2mm, and their lengths were 8, 10, 12 and 14mm. The drill procedure was directly through the cortical bone without any incision or flap operation. Two weeks later, a force of 100-200g was applied by an elastometric chain or NiTi coil spring. Risk factors for the failure of mini-implants were examined statistically using the Chi-square or Fisher exact test as applicable. The average placement time of a mini-implant was about 10-15min. Four mini-implants loosened after orthodontic force loading. The overall success rate was 91.1%. The location of the implant was the significant factor related to failure. In conclusion, the mini-implants are easy to insert for skeletal anchorage and could be successful in the control of tooth movement.     

Bone response to modified titanium surface implants in nonhuman primates (Papio ursinus) and humans: histological evaluation

The aim of this study is a comparative histological and histomorphometrical evaluation of the effect on early bone formation of 2 different implant surfaces: a machined and a new acid-etched implant surface (Leader, Milano, Italy). Ten screw-type microimplants were placed in 5 patients. Each patient received 2 microimplants (2 mm in diameter and 5 mm in length): 1 with a machined surface (control) and 1 with an acid-etched surface (test). The microimplants were retrieved after 60 days of healing with a 4-mm trephine bur and processed for histology. Moreover, 24 regular size implants--12 with a machined surface (control) and 12 with an acid-etched surface (test)--were placed in 2 adult nonhuman primates 3 months after the extraction of premolars and molars. Each animal received 3 machined implants (control) in the right hemimandible and 3 acid-etched implants (test) in the left hemimandible. The same animals received 3 control implants and 3 test implants in the rectus abdominis muscle. After 1 month, the implants were retrieved from the mandible and the rectus abdominis muscle and processed for histology. Histomorphometric evaluation demonstrated a higher bone-to-implant contact in the test implants compared with the controls in both primates (25.55% vs 15.8%) and humans (62% vs 45%). Moreover, in nonhuman primates after 1 month of healing, it was possible to observe a poor osseointegration in the control specimens, while newly formed bone in direct contact with test implants was evident. The rectus abdominis muscle specimens showed that the acid-etched surfaces can stimulate the formation and attachment of new connective and vascular tissues more than machined surfaces can. Implant surface geometry can speed up bone formation by the development of a special microenvironment that promotes angiogenesis. Long-term studies are needed to further test this new acid-etched implant surface.     

纯钛阳极氧化伴水热处理后羟基磷灰石薄涂层种植体的实验研究

目的：了解阳极氧化伴水热处理后纯钛种植的体内成骨效应。方法：36枚纯钛种植体采用4种表面处理,随机植入12只兔股骨内,分别在术后4周、8周、16周取出带种植体骨块制作磨片,观察界面新生骨情况以及抛光、水热处理种植体术后8周的界面超微结构,行表面能谱分析。结果：术后8周,阳极氧化伴水热处理种植体表面编码骨的转化和成熟较快,至16周时界面几乎无编织骨和剥脱的羟基磷灰石碎片,种植体表面的钙,磷含量在种植后增加,抛光种植体表面钙、磷含量增加不明显。结论：纯钛经阳极氧化伴水热处理后,可以加快种植表现编织骨转化为板层骨,从而可能促进种植区的早期愈合,薄涂层特有的优越性尚待进一步研究。     

In vivo low-density bone apposition on different implant surface materials

During osseointegration, new bone may be laid down on the implant surface and/or on the old bone surface; the former is known as contact osteogenesis and the latter as distance osteogenesis. Implant surface topography and material composition affect this process. The present study evaluates Ca and P apposition onto three different dental implant material surfaces (carbon monoxide (CO) ion implantation on Ti6Al4V, sand blasting and acid etching on commercially pure titanium and untreated Ti6Al4V) on the mandibles of beagles after healing periods of 3 and 6 months. Energy dispersive spectroscopy is useful for identifying low-density bone relative to surrounding mature bone, allowing for discrimination of the osteogenesis source. Low-density bone was only found at the apical end; there was none on the surface of untreated implants. Low-density bone arising from mature bone towards the implant at month 3 (i.e. distance osteogenesis) was only present on the CO ion implanted samples, due to the modification of the surface nano-topography and the chemistry and structure of the material.     

Recommended placement torque when tightening an orthodontic mini-implant

To determine an adequate placement torque for obtaining a better success rate of mini-implants that are screwed into the buccal alveolar bone of the posterior region as an anchor for orthodontic treatment, implant placement torque (IPT) was measured. The subjects were 41 orthodontic patients (124 implants), with an average age of 24.9 years (SD 6.5 years), who had surgery to place titanium mini-implants. The peak value of IPT was measured using a torque screwdriver. The success rate of the mini-implant anchor for 124 implants was 85.5%. The mean IPT ranged from 7.2 to 13.5 N cm, depending on the location of the implants. There was a significant difference in the IPT between maxilla and mandible. The IPT in the mandible was, unexpectedly, significantly higher in the failure group than in the success group. Therefore, a large IPT should not be used always. According to our calculations of the risk ratio for failure, to raise the success rate of 1.6-mm diameter mini-implants, the recommended IPT is within the range from 5 to 10 N cm.     

Histologic and histomorphometric findings from retrieved, immediately occlusally loaded implants in humans

BACKGROUND: The immediate loading treatment concept can be successfully used in implant dentistry. Bone cells migrate onto the implant surface and establish a stable anchorage on the titanium surface. When implants are loaded immediately after surgery, there is a high long-term success rate of the implant-supported reconstruction. Based on histologic observations from different animal studies, the interface of immediately loaded implants can have a direct bone-to-implant connection without any fibrous tissue formation. Mature bone formation is dependent on the loading period. The aim of this study was to demonstrate a histologic analysis of retrieved, clinically stable immediately loaded implants with different implant designs and surfaces. An objective demonstration of the bone-implant interface was presented for the implant systems used. METHODS: A total of 29 implants with different implant designs and surfaces were retrieved from patients who were treated with implants using an immediate loading protocol and fixed immediate restorations placed the same day after surgery. The loading period was between 2 and 10 months. The bone-implant interface was examined histologically and histomorphometrically. RESULTS: A high bone-to-implant percentage of 66.8% (+/-8.9%) was found in the examined retrieved implants. Some marginal bone resorption was observed in the crestal part of the implants. CONCLUSION: According to the present histologic and histomorphometric evaluation of retrieved, clinically stable implants, immediate occlusal loading can present a high level of bone-to-implant contact in humans.     

Effect of controlled early implant loading on bone healing and bone mass in guinea pigs, as assessed by micro-CT and histology

Without controlled loading, the failure of early loaded oral implants is higher than in delayed loading, unless loading regimens can be identified that stimulate bone formation. The purpose of this study was to investigate whether controlled early loading optimizes osseointegration. Six series of guinea pigs received percutaneous implants in both tibiae. One implant was stimulated, the contra-lateral served as the control. The strain rate amplitude varied from 1,620 to 12,000 microstrain s(-1). In vivo microfocus computed tomography (micro-CT) was used to study the peri-implant bone at three time points: 1 wk after implantation, but before starting stimulation (V1); 2 wk after stimulation (V2); and 4 wk after stimulation, after the guinea pigs were killed (PM). Bone implant contact and bone mass [BM (%) bone occupied area fraction] were analyzed. The implant failure was 5.9% (six control/one test). Although bone implant contact did not significantly differ, bone mass in the distal half peri-implant marrow cavity was significantly higher around test implants. Strain rate amplitude and the difference in bone mass between test and control implants were inversely correlated. A strain rate amplitude of 1,620 microstrain s(-1) in the cortical bone at a distance of 1.3 mm from the implant showed the highest effect. Based on these results, early loading did not negatively affect the implant outcome. On the contrary, an improved bone reaction in the marrow cavity around early loaded implants was achieved.     

Enhanced osteoconductivity of micro-structured titanium implants (XiVE S CELLplus™) by addition of surface calcium chemistry: a histomorphometric study in the rabbit femur

Objectives: This study evaluated the osseointegration in rabbit cancellous bone of titanium (Ti) implants with a micro-topographically complex surface structure produced by grit-blasting/acid-etching with or without the addition of surface calcium ion (Ca) chemistry.
Material and methods: Micro-structured Ti implants (XiVE S CELLplus^™ screw implant, Dentsply Friadent GmbH) were hydrothermally treated in an alkaline Ca-containing solution to produce a nano-structured Ca-incorporated oxide surface layer. The surface characteristics were evaluated by scanning electron microscopy and stylus profilometry before and after Ca surface treatment. Twenty implants (10 control and 10 experimental) were placed in the femoral condyles of 10 New Zealand White rabbits. Histomorphometric analysis was performed 6 weeks after implantation.
Results: Ca-incorporated and untreated control implants showed similar surface morphologies and surface roughness values at the micron scale. Untreated micro-structured Ti implants achieved a high degree of bone-to-implant contact (BIC), and Ca incorporation further increased BIC% ( P <0.05). Active new bone apposition was found on surfaces of Ca-incorporated implants in areas of loose trabeculae.
Conclusion: The nano-structured Ca-incorporated oxide surface significantly enhanced osteoconductivity of micro-structured Ti implants in rabbit cancellous bone. Results indicate that this surface produced by simple hydrothermal treatment may be effective in improving the osseointegration of implants with micro-topographically complex surface structures in areas of loose cancellous bone.     

Bone response of Mg ion‐implanted clinical implants with the plasma source ion implantation method

Objectives: This study examined the bone response of magnesium (Mg) ion‐implanted implants produced using a plasma source ion implantation method. Materials and methods: The surface characteristics were evaluated by scanning electron microscopy, Auger electron spectroscopy, X‐ray photoelectron spectroscopy, and Rutherford backscattering spectroscopy. The screw‐type titanium implants were treated with resorbable blasting media (RBM) and divided into one control group (RBM implants) and three test groups (Mg ion‐implanted implants with different retained Mg doses). Twenty‐four implants from each group were placed into the tibiae of 24 New Zealand white rabbits. After allowing 6 weeks for healing, the removal torque (RTQ) was measured and the implants were subjected to histomorphometric analysis. Results: The surface roughness and surface morphology of the test groups were similar. The Mg ion‐implanted implants with a 2.3 × 10¹⁵ ions/cm² retained dose showed a significantly higher RTQ than the other implants. Histomorphometric analysis indicated that the bone contact of this group was superior to the other groups. Conclusion: The bone response of Mg ion‐implanted implant showed results superior or similar to an RBM‐treated implant. The optimal Mg ion concentration that induced the strongest osseointegration was approximately 9%. To cite this article:
Cho L‐R, Kim D‐G, Kim J‐H, Byon E‐S, Jeong Y‐S, Park C‐J. Bone response of Mg ion‐implanted clinical implants with plasma source ion implantation method.
Clin. Oral Impl. Res. 21 , 2010; 848–856.
doi: 10.1111/j.1600‐0501.2009.01862.x     

Effect of cortical bone thickness and implant placement torque on stability of orthodontic mini-implants

PURPOSE: To examine the relationship between cortical bone thickness, inter-root distance (horizontal space), distance from alveolar crest to the bottom of maxillary sinus (vertical space) at the prepared site, and implant placement torque and the success rate of mini-implants placed for orthodontic anchorage. MATERIALS AND METHODS: After computerized tomography examination, mini-implants 1.6 mm wide and 8 mm long were placed in the posterior alveolar bone. The mini-implant was judged a success when orthodontic force could be applied for at least 6 months without pain or clinically detectable mobility. The unpaired t test was performed to examine differences between the success and failure groups. The chi-square analysis or Fisher exact probability test was used to compare the implant success according to placement torque, location, and patient gender. P values less than .05 were considered significant. RESULTS: The subjects included 4 males (11 implants) and 28 females (76 implants) who ranged in age from 14.6 to 42.8 years. The success rate of the 87 implants was 87.4%. Cortical bone thickness was significantly greater in the success group (1.42 +/- 0.59 mm vs 0.97 +/- 0.31 mm, P = .015). The success rate was significantly higher in the group with an implant placement torque of 8 to 10 Ncm (100%) as compared to implants with higher or lower placement torques. The odds ratio for failure of the mini-implant was 6.93 (P = .047) when the cortical bone thickness was less than 1.0 mm relative to 1.0 mm or more. CONCLUSION: A relationship between stability after implant placement and the width and height of the peri-implant bone was not demonstrated. The prepared site should have a cortical bone thickness of at least 1.0 mm, and the placement torque should be controlled up to 10 Ncm.     

Effect of platelet-rich plasma on the early bone formation around Ca-P-coated and non-coated oral implants in cortical bone

OBJECTIVES: The purpose of the present study was to investigate the effect of local application of platelet-rich plasma (PRP) on the early healing of cortical bone around Ti implants with two different surface configurations. MATERIAL AND METHODS: Six goats were used in this study. PRP fractions were obtained from a venous blood sample of the goats and administered immediately before implant insertion. PRP was applied via gel preparation and installation of the gel into the implant site, or via dipping of the implants in PRP fraction before insertion. A total of 36 implants (18 non-coated and 18 Ca-P-coated) were placed into the tibial cortical bone. The animals were sacrificed at 6 weeks after implantation and implants with surrounding tissue were prepared for histological examination. Histomorphometrical variables like the percentage of implant surface with direct bone-implant contact and the percentage of new and old bone adjacent to the implant were evaluated. RESULTS: More interfacial bone-to-implant contact was observed for all the three groups of Ca-P-coated implants and the Ti/PRP liquid group. All groups revealed similar percentages of old and new bone adjacent to the implant. CONCLUSIONS: It was concluded that the additional use of PRP did not have any effect on the early cortical bone response to the Ca-P-coated implants, while PRP in a liquid form showed a tendency to increase bone apposition to roughened titanium implants.     

Development and evaluation of a new surface treatment method for titanium alloy implants

We developed and evaluated a new method of titanium surface treatment for direct bone fixation of implants. This method consists of hydroxyapatite (HA) flame coating onto a porous titanium surface which is arc-sprayed with pure titanium material in argon gas at atmospheric pressure. The surface roughness of the porous layer was 360 microm, Rmax, and showed higher resistance to blast erosion in comparison with the conventional low-pressure plasma-sprayed porous layers of titanium. The thickness of the HA layer was between 20 and 40 microm considering the balance of bone conduction effect of HA and the possibility of mechanical detachment of the layers from the porous titanium. Short-term animal tests showed excellent results. This new surface treatment method was applied to cementless total hip joints which were used clinically. The results obtained from observations of the retrieved specimens show that the thickness of the HA coating layer is sufficient for the new bone formation after implantation. It was concluded that the new surface treatment method for titanium alloy implants is effective and successful for direct bone fixation.     

Osseotite vs. machined surface in poor bone quality. A study in dogs

Implant sites with low bone content have exhibited lower implant survival rates than dense bone areas. Alterations of the implant surface seem to influence the bone-to-implant contact rate and may have an impact on implant failure rates in such sites. It was the objective of this animal study to histomorphometrically compare two different implant surfaces in so-called poor bone quality sites. All premolars on one side of the mandible were extracted in five fox hounds. After a healing time of 8 months, four screw-type implants (two with a machined surface (ICE group) and two with a double acid-etched (Osseotite) surface (OSS group)) were inserted into the mandible. Upon insertion, the implant apex was located in the 'hollow' part of the dog mandible, where the bone content is low. After 4 months healing, histomorphometric evaluations were performed. All implants osseointegrated clinically and histologically. Periapical density measurements revealed similar bone contents in both groups (ICE 49.9+/-16.7%, OSS 52.2+/-8.4%; P>0.05). Despite these similar amounts of bone content in the apical area around the implant, the Osseotite implant surface had a significantly higher bone-to-implant contact rate than the machined surface (OSS 62.9+/-12.4%, ICE 39.5+/-13.0%; P<0.01). It is concluded from this animal experiment that, in poor bone quality sites, an implant with an Osseotite surface can achieve a significantly higher bone-to-implant contact compared to a machined surface.     

Vertical Osteoconductive Characteristics of Titanium Implants with Calcium‐Phosphate‐Coated Surfaces – A Pilot Study in Rabbits

Introduction: Osteoconductive characteristics of different implant surface coatings are in the focus of current interest. The aim of the present study was to compare the vertical osteoconductivity at the implant shoulder of supracrestal inserted calcium‐phosphate coated implants (SLA‐CaP) with conventional sand‐blasted/acid‐etched (SLA) implants in a rabbit model. Materials and Methods: SLA‐CaP and SLA implants were inserted bilaterally in the mandible of four rabbits in a split‐mouth design. The implants were placed 2 mm supracrestal. After 3 weeks, at the left and right implant shoulder, the percentage of linear bone fill (PLF) as well as bone‐implant contact (BIC‐D) were determined. Results: After 3 weeks, newly formed woven bone could be found at the shoulder of the most of both surface‐treated implants (75%). PLF was significantly higher in SLA‐CaP implants (11.2% vs. 46.5%; n = 8, p = .008). BIC‐D was significantly increased in the SLA‐CaP implants (13.0% vs. 71.4%; n = 8, p < .001) as well. Conclusion: The results of this study show for the first time that calcium‐phosphate coated surfaces on supracrestal inserted implants have vertical osteoconductive characteristics and increase the bone‐implant contact at the implant shoulder significantly in a rabbit model. In clinical long‐term settings, these implants may contribute to a better vertical bone height.