Early healing of implants placed into fresh extraction sockets: an experimental study in the beagle dog. De novo bone formation

Objectives: Describe the early phases of tissue integration in implants placed into fresh extraction sockets and test whether a new implant surface nano‐topography (DCD nano‐particles, Nanotite^?) promotes early osseointegration when compared with minimally rough surface implants (DAE, Osseotite^®). Material and Methods: Sixteen beagle dogs received 64 test and control implants randomly installed into the distal socket of ₃P₃ and ₄P₄. Histomorphometric analysis of bone to implant contact (BIC) and bone area was performed at 4 h, 1, 2, 4 and 8 weeks. Results: Wound healing initiated with a coagulum that was substituted by a provisional matrix at 1 week. Bone formation started concomitant to a marked bone resorption. At 2 weeks, woven bone formation was evident and gradually remodelled into lamellar bone at 4 and 8 weeks. BIC increased similarly throughout the study in both groups with a tendency to higher percentages for the test devices at 2 and 4 weeks. The influence of the DCD nano‐particles was more evident at the fourth premolar site. Conclusion: Osseointegration occurred similarly at both implant groups, although the socket dimension appeared to influence bone healing. It is suggested that the enhanced nano‐topography has a limited effect in the immediate implant surgical protocol.     

In vivo performance of zirconia and titanium implants: a histomorphometric study in mini pig maxillae

Objectives: To compare the bone tissue response to surface‐modified zirconia (ZrO₂) and titanium implants. Methods: Cylindrical low‐pressure injection moulded zirconia (ZrO₂) implants were produced with an acid‐etched surface. Titanium implants with identical shape, sandblasted and acid‐etched surface (SLA) served as controls. Eighteen adult miniature pigs received both implant types in the maxilla 6 months after extraction of the canines and incisors. The animals were euthanized after 4, 8 and 12 weeks and 16 zirconia and 18 titanium implants with the surrounding tissue were retrieved, embedded in methylmethacrylate and stained with Giemsa–Eosin. The stained sections were digitized and histomorphometrically analysed with regard to peri‐implant bone density (bone volume/total volume) and bone–implant contact (BIC) ratio. Statistical analysis was performed using Mann–Whitney' U‐test. Results: Histomorphometrical analysis showed direct osseous integration for both materials. ZrO₂ implants revealed mean peri‐implant bone density values of 60.4% (SD ± 9.9) at 4 weeks, 65.4% (SD ± 13.8) at 8 weeks, and 63.3% (SD ± 21.5) at 12 weeks after implantation, whereas Ti‐SLA implants demonstrated mean values of 61.1% (SD ± 6.2), 63.6% (SD ± 6.8) and 68.2% (SD ± 5.8) at corresponding time intervals. Concerning the BIC ratio, the mean values for ZrO₂ ranged between 67.1% (SD ± 21.1) and 70% (SD ± 14.5) and for Ti‐SLA between 64.7% (SD ± 9.4) and 83.7% (SD ± 10.3). For the two parameters investigated, no significant differences between both types of implants could be detected at any time point. Conclusion: The results indicate that there was no difference in osseointegration between ZrO₂ implants and Ti‐SLA controls regarding peri‐implant bone density and BIC ratio. To cite this article :
Gahlert M, Roehling S, Sprecher CM, Kniha H, Milz S, Bormann K. In vivo performance of zirconia and titanium implants: a histomorphometric study in mini pig maxillae.
Clin. Oral Impl. Res. 23 , 2012; 281–286.
doi: 10.1111/j.1600‐0501.2011.02157.x     

Fracture strength of zirconia implants after artificial aging

Background: Zirconia (ZrO₂) might be an alternative material to titanium (Ti) for dental implant fabrication. However, no data are available on the fracture strength of one‐piece ZrO₂ oral implants. Purpose: The objective of this study was to evaluate the fracture strength of ZrO₂ implants after exposure to the artificial mouth. Materials and Methods: One hundred twenty ZrO₂ and Ti implants were used. The Ti implants were divided into two control groups (A and B). ZrO₂ implants manufactured from yttria‐stabilized tetragonal ZrO₂ polycrystal (Y‐TZP) in group C, from Y‐TZP dotted with alumina (Y‐TZP‐A) in group D, and from Y‐TZP‐A with a modified surface in groups E and F were used. In group F, the implant heads were prepared, and in group G, the implants were restored with ZrO₂ crowns. Each group included 16 samples with the exception of group D, which included 24 samples. A subgroup of each implant type (eight implants) was subjected to thermomechanical cycling in a chewing simulator prior to fracture testing. Test specimens were then loaded until a fracture occurred. Results: Seven of the 120 samples failed in the chewing simulator. ZrO₂ implant fracture occurred at 725 to 850 N when the implants were not prepared, and at 539 to 607 N when prepared. The samples in group A fractured at the level of the abutment screw. All ZrO₂ implants fractured at the level of the Technovit® resin (Heraeus Kulzer GmbH & Co., Wehrheim, Germany). No fracture of the ZrO₂ crowns in group G was observed. Conclusion: Mean fracture strength values obtained were all within the limits of clinical acceptance. However, implant preparation had a statistically significant negative influence on the implant fracture strength. Long‐term clinical data are necessary before one‐piece ZrO₂ implants can be recommended for daily practice.     

Evaluation of a New Titanium‐Zirconium Dental Implant: A Biomechanical and Histological Comparative Study in the Mini Pig

Background: Titanium zirconium alloy with 13–17% zirconium (TiZr1317) shows significantly better mechanical attributes than pure Ti with respect to elongation and fatigue strength. This material may be suitable for thin implants and implant components exposed to high mechanical constraints. Purpose: The aim of this study was to test the hypothesis that TiZr1317 and Ti implants show comparable osseointegration and stability. Materials and Methods: The mandibular premolars (P1, P2, P3) and the first molar (M1) in 12 adult miniature pigs were extracted 3 months prior to the study. Six specially designed implants made from Ti (commercially pure, Grade 4) or TiZr1317 (Roxolid®, Institut Straumann AG, Basel, Switzerland) with a hydrophilic sandblasted and acid‐etched (SLActive, Institut Straumann AG, Basel, Switzerland) surface were placed in each mandible; three standard implants modified for evaluation of removal torque (RT) in one side and three bone‐chamber implants for histologic observations in the contralateral side. RT tests were performed after 4 weeks when also the bone chamber implants and surrounding tissue were biopsied for histologic analyses in ground sections. Results: The RT results indicated significantly higher stability (p = 0.013) for TiZr1317 (230.9 ± 22.4 Ncm) than for Ti implants (204.7 ± 24.0 Ncm). The histology showed similar osteoconductive properties for both implant types. Histomorphometric measurements showed a statistically significant higher (p = 0.023) bone area within the chamber for the TiZr1317 implants (45.5 ± 13.2%) than did the Ti implants (40.2 ± 15.2%). No difference was observed concerning the bone to implant contact between the groups with 72.3 ± 20.5% for Ti and 70.2 ± 17.3% for TiZr1317 implants. Conclusion: It is concluded that the TiZr1317 implant with a hydrophilic sandblasted and acid‐etched surface showed similar or even stronger bone tissue responses than the Ti control implant     

Vitamin D Status and Periodontal Disease Among Pregnant Women

Background: Maternal periodontal disease is found in ≤40% of pregnant women and is associated with adverse pregnancy outcomes. Vitamin D deficiency may play a role in periodontal disease and tooth loss, and insufficient vitamin D status is common among pregnant women. The objective of this study is to examine the relationship between maternal vitamin D status and periodontal disease. Methods: A case‐control study was conducted. Cases were defined as pregnant women with clinical moderate to severe periodontal disease; controls were pregnant women who were periodontally healthy. Maternal data were chart abstracted and serum was collected between 14 and 26 weeks of gestation. Serum 25‐hydroxyvitamin D (25[OH]D) levels were measured using liquid chromatography–tandem mass spectrometry. Median serum 25(OH)D levels and prevalence of vitamin D insufficiency (defined as <75 nmol/l) were compared between cases and controls. The odds ratio and 95% confidence interval for moderate to severe periodontal disease among women with vitamin D insufficiency was calculated using multivariable logistic regression, adjusting for maternal race, season of blood draw, and other potential confounders. Results: A total of 117 cases were compared to 118 controls. Cases had lower median 25(OH)D levels than controls (59 versus 100 nmol/l; P <0.001) and were more likely to have vitamin D insufficiency (65% versus 29%; P <0.001). The adjusted odds ratio (95% confidence interval) for moderate to severe periodontal disease among women with vitamin D insufficiency was 2.1 (0.99 to 4.5). Conclusions: Vitamin D insufficiency (serum 25[OH]D <75 nmol/l) is associated with maternal periodontal disease during pregnancy. Vitamin D supplementation represents a potential therapeutic strategy to improve maternal oral health.     

Osseointegration of commercial microstructured titanium implants incorporating magnesium: a histomorphometric study in rabbit cancellous bone

Objective: Recent studies have suggested that magnesium (Mg) ions exert a beneficial effect on implant osseointegration. This study assessed the osseointegration of nanoporous titanium (Ti) surface incorporating the Mg produced by hydrothermal treatment in rabbit cancellous bone to determine whether this surface would further enhance bone healing of moderately rough‐surfaced implants in cancellous bone, and compared the result with commercially available micro‐arc oxidized Mg‐incorporated implants. Material and methods: The Mg‐incorporated Ti surfaces (RBM/Mg) were obtained by hydrothermal treatment using an alkaline Mg‐containing solution on grit‐blasted moderately rough (RBM) implants. Untreated RBM and recently introduced Mg‐incorporated microporous Ti implants produced by micro‐arc oxidation (M) were used controls in this study. The surface characteristics were evaluated by scanning electron microscopy, X‐ray photoelectron spectroscopy and optical profilometry. Twenty‐four threaded implants with a length of 10 mm (eight RBM implants, eight RBM/Mg implants and eight M implants) were placed in the femoral condyles of 12 New Zealand White rabbits. Histomorphometric analysis was performed 4 weeks after implantation. Results: Hydrothermally treated and untreated grit‐blasted implants displayed almost identical surface morphologies and R_a values at the micron‐scale. The RBM/Mg implants exhibited morphological differences compared with the RBM implants at the nano‐scale, which displayed nanoporous surface structures. The Mg‐incorporated implants (RBM/Mg and M) exhibited more continuous bone apposition and a higher degree of bone‐to‐implant contact (BIC) than the untreated RBM implants in rabbit cancellous bone. The RBM/Mg implants displayed significantly greater BIC% than untreated RBM implants, both in terms of the all threads region and the total lateral length of implants (P<0.05), but no statistical differences were found between the RBM/Mg and M implants except BIC% values in total lateral length. Conclusion: These results indicate that a nanoporous Mg‐incorporated surface may be effective in enhancing the osseointegration of moderately rough grit‐blasted implants by increasing the degree of bone?implant contact in areas of cancellous bone. To cite this article :
Park J‐W, An C‐H, Jeong S‐H, Suh J‐Y. Osseointegration of commercial microstructured titanium implants incorporating magnesium: a histomorphometric study in rabbit cancellous bone.
Clin. Oral Impl. Res. 23 , 2012; 294–300.
doi: 10.1111/j.1600‐0501.2010.02144.x     

Bone formation at recombinant human bone morphogenetic protein-2-coated titanium implants in the posterior mandible (Type II bone) in dogs

Background: Conventional oral/maxillofacial implants reach osseointegration over several months during which the titanium fixtures interact with alveolar bone. The objective of this study was to determine if adsorbing recombinant human bone morphogenetic protein‐2 (rhBMP‐2) onto a titanium porous oxide (TPO) implant surface might enhance or accelerate local bone formation and support osseointegration in a large animal oral/maxillofacial orthotopic model. Material and Methods: Endosseous implants with a TPO surface were installed into the edentulated posterior mandible in eight adult Hound Labrador mongrel dogs. The implant surface had been adsorbed with rhBMP‐2 at 0.2 or 4.0 mg/ml. TPO implants without rhBMP‐2 served as control. Treatments were randomized between jaw quadrants. Mucosal flaps were advanced and sutured leaving the implants submerged. Clinical and radiographic evaluations were made immediately post‐surgery, at day 10 (suture removal), and week 4 and 8 post‐surgery. The animals received fluorescent bone markers at week 3, 4, and at week 8 post‐surgery, when they were euthanized for histologic analysis. Results: TPO implants coated with rhBMP‐2 exhibited dose‐dependent bone remodelling including immediate resorption and formation of implant adjacent bone, and early establishment of clinically relevant osseointegration. The resulting bone–implant contact, although clinically respectable, appeared significantly lower for rhBMP‐2‐coated implants compared with the control [rhBMP‐2 (0.2 mg/ml) 43.3±10.8%versus 71.7±7.8%, p<0.02; rhBMP‐2 (4.0 mg/ml) 35.4±10.6%versus 68.2±11.0%, p<0.03]. Conclusions: rhBMP‐2 adsorbed onto TPO implant surfaces initiates dose‐dependent peri‐implant bone re‐modelling resulting in the formation of normal, physiologic bone and clinically relevant osseointegration within 8 weeks.     

Tissue integration of a new titanium-zirconium dental implant: a comparative histologic and radiographic study in the canine

Background: This study evaluates a newly developed titanium–zirconium implant (TiZr), comparing it to a commercially available pure titanium (Ti) implant subjected to the same surface treatment. Methods: In nine dogs, 12 implants (six TiZr and six Ti) were randomly placed in the mandible with the implant shoulder at the bone crest and subjected to submerged healing. Standardized radiographs were taken after implantation, and at the sacrifice of 2 weeks (three dogs), 4 weeks (three dogs), and 8 weeks (three dogs). Histologic and histomorphometric measurements were performed on non‐decalcified histologic sections. The main outcome measures included the first bone–implant contact (fBIC) and BIC over time. For statistical analysis, Wilcoxon signed‐rank test and mixed model regressions were applied. Results: From baseline to 8 weeks, a mean bone loss of 0.09 ± 0.33 mm for TiZr and a gain of 0.02 ± 0.33 mm for Ti were calculated radiographically. The number of implants with the fBIC coronal to the reference point (implant shoulder) gradually increased over time, reaching 39% of all TiZr implants and 50% of all Ti implants at 8 weeks. The mean fBIC values for Ti and TiZr were 0.29 ± 0.42 mm and 0.26 ± 0.32 mm (2 weeks), ?0.01 ± 0.20 mm and 0.10 ± 0.28 mm (4 weeks), and ?0.06 ± 0.22 mm and 0.08 ± 0.30 mm (8 weeks), respectively. The mean BIC values peaked at 86.9% ± 6.8% (8 weeks) for TiZr and at 83.4% ± 5.9% (4 weeks) for Ti. No statistically significant differences were observed at any time point. Conclusion: TiZr and Ti bone level implants with chemically‐modified, sandblasted, and acid‐etched surfaces performed similarly in regards to osseointegration in this unloaded canine study.     

Evaluation of implant osseointegration with different regeneration techniques in the treatment of bone defects around implants: an experimental study in a rabbit model

Aim: The aim of this study was to evaluate the osseointegration of implants placed in areas with artificially created bone defects, using three bone regeneration techniques. Material and methods: The experimental model was the rabbit femur (16), where bone defects were created and implants were placed. The peri‐implant bone defects were filled with a deproteinized bovine bone mineral, NuOss^? (N), NuOss^? combined with plasma rich in growth factors (PRGF) (N+PRGF), NuOss^? covered by an RCM⁶ membrane (N+M), or remained unfilled (control group [C]). After 4 and 8 weeks, the animals were euthanized and bone tissue blocks with the implants and the surrounding bone tissue were removed and processed according to a histological protocol for hard tissues on non‐decalcified ground sections. The samples were studied by light and electron scanning microscopy, histometric analysis was performed to assess the percentage of bone in direct contact with the implant surface and a statistical analysis of the results was performed. Results: In the samples analyzed 4 weeks after implantation, the percentage of bone tissue in direct contact with the implant surface for the four groups were 57.66±24.39% (N), 58.62±20.37% (N+PRGF), 70.82±20.34 % (N+M) and 33.07±5.49% (C). In the samples with 8 weeks of implantation time, the percentage of bone in direct contact was 63.35±27.69% (N), 58.42±24.77% (N+PRGF), 78.02±15.13% (N+M) and 40.28±27.32% (C). In terms of the percentage of bone contact, groups N and N+M presented statistically significant differences from group C in the 4‐week trial test (P<0.05; ANOVA). For the 8‐week results, only group N+M showed statistically significant differences when compared with group C (P<0.05; ANOVA). Conclusion: In conclusion, the NuOss^? granules/RCM⁶ membrane combination presented a percentage of bone contact with the implant surface statistically greater than in the other groups. To cite this article:
Guerra I, Branco FM, Vasconcelos M, Afonso A, Figueiral H, Zita R. Evaluation of implant osseointegration with different regeneration techniques in the treatment of bone defects around implants: an experimental study in a rabbit model.
Clin. Oral Impl. Res. 22 , 2011; 314–322.
doi: 10.1111/j.1600‐0501.2010.02002.x     

Flapless Implant Surgery Using a Mini‐Incision

Background: Traditional flapless implant surgery using a soft tissue punch device requires a circumferential excision of keratinized tissue at the implant site. A new flapless implant technique that can submerge implant fixtures is needed. Purpose: This article describes a flapless implant surgery method using a mini‐incision and compares the effects of soft tissue punch and mini‐incision surgery on both the amount of osseointegration and the bone height around the implants using a canine mandible model. Materials and Methods: Bilateral, edentulated, flat alveolar ridges were created in the mandibles of six mongrel dogs. After a 3‐month healing period, two implants were placed on each side of the mandible using either soft tissue punch or mini‐incision procedures. After an additional 3‐month healing period, a second stage surgery and transmucosal abutment attachment was performed for mini‐incision implant cases. Following a 2‐month healing period, the dogs were sacrificed to evaluate the osseointegration and bone height around the implants. Results: Average bone height was 9.6 ± 0.4 mm in the soft tissue punch group and 9.8 ± 0.3 mm in the mini‐incision group (p > .05). Average osseointegration was 70.4 ± 6.3% in the soft tissue punch group and 71.2 ± 7.1% in the mini‐incision group (p > .05). No significant differences were noted between the two groups in vertical alveolar ridge height or bone/implant contact. Conclusions: Our findings support the clinical use of mini‐incision implant surgery at sites where implants need to be protected below the soft tissue during the early phase of healing, particularly for patients with poor bone quality and/or low primary implant stability.     

Alveolar ridge augmentation using implants coated with recombinant human bone morphogenetic protein-2: histologic observations

Background: Studies using ectopic rodent, orthotopic canine, and non‐human primate models show that bone morphogenetic proteins (BMPs) coated onto titanium surfaces induce local bone formation. The objective of this study was to examine the ability of recombinant human BMP‐2 (rhBMP‐2) coated onto a titanium porous oxide implant surface to stimulate local bone formation including osseointegration and vertical augmentation of the alveolar ridge. Material and Methods: Bilateral, critical‐size, 5 mm, supra‐alveolar, peri‐implant defects were created in 12 young adult Hound Labrador mongrel dogs. Six animals received implants coated with rhBMP‐2 at 0.75 or 1.5 mg/ml, and six animals received implants coated with rhBMP‐2 at 3.0 mg/ml or uncoated control. Treatments were randomized between jaw quadrants. The mucoperiosteal flaps were advanced, adapted and sutured to submerge the implants for primary intention healing. The animals received fluorescent bone markers at weeks 3, 4, 7 and 8 post‐surgery when they were euthanized for histologic evaluation. Results: Jaw quadrants receiving implants coated with rhBMP‐2 exhibited gradually regressing swelling that became hard to palpate disguising the contours of the implants. The histologic evaluation showed robust bone formation reaching or exceeding the implant platform. The newly formed bone exhibited characteristics of the adjoining resident Type II bone including cortex formation for sites receiving implants coated with rhBMP‐2 at 0.75 or 1.5 mg/ml. Sites receiving implants coated with rhBMP‐2 at 3.0 mg/ml exhibited more immature trabecular bone formation, seroma formation and peri‐implant bone remodelling resulting in undesirable implant displacement. Control implants exhibited minimal, if any, bone formation. Thus, implants coated with rhBMP‐2 at 0.75, 1.5 and 3.0 mg/ml exhibited significant bone formation (height and area) compared with the sham‐surgery control averaging (±SD) 4.4±0.4, 4.2±0.7 and 4.2±1.2 versus 0.8±0.3 mm; and 5.0±2.2, 5.6±2.2 and 7.4±3.5 versus 0.7±0.3 mm², respectively (p<0.01). All the treatment groups exhibited clinically relevant osseointegration. Conclusions: rhBMP‐2 coated onto titanium porous oxide implant surfaces induced clinically relevant local bone formation including vertical augmentation of the alveolar ridge and osseointegration. Higher concentrations/doses were associated with untoward effects.     

Increased bone apposition on a titanium oxide surface incorporating phosphate and strontium

Objective: This study investigated the osteoconductivity of titanium (Ti) implants with a phosphate (P)‐ and strontium (Sr) ion‐incorporated oxide surface, produced by hydrothermal treatment in the rabbit cortical and cancellous bone, for future biomedical applications as a biocompatible endosseous implant surface. Material and methods: The P‐ and Sr ion‐incorporated Ti implants (P/Sr implant) were produced by hydrothermal treatment using a P‐ and Sr‐containing solution. The surface characteristics were evaluated by scanning electron microscopy, thin‐film X‐ray diffractometry, X‐ray photoelectron spectroscopy and optical profilometry. Forty screw implants (20 control and 20 experimental) were placed in the tibiae and femoral condyles of 10 New Zealand White rabbits. The surface in vivo osteoconductivity of the P/Sr implants was compared with micro‐arc oxidized (TO) implants with surface calcium and P chemistry by histomorphometric analysis in the cortical and cancellous bone after 4 weeks of implantation. Results: The P/Sr implants showed moderately rough surface features and had lower R_a values than the TO implants. Histologically, more direct bone apposition was observed on the surface of the P/Sr implants. The P/Sr implants displayed significantly higher bone‐to‐implant contact percentages compared with the TO implant in both the tibiae and the femoral condyles (P<0.01). Conclusion: The results indicate that the hydrothermally produced P‐ and Sr ion‐incorporated Ti oxide surface may be effective in improving implant osseointegration in both cortical and cancellous bone by increasing bone apposition, due to its surface properties combining micro‐topography, P/Sr chemistry and superior wettability. To cite this article:
Park J‐W. Increased bone apposition on a titanium oxide surface incorporating phosphate and strontium.
Clin. Oral Impl. Res. 22 , 2011; 230–234.
doi: 10.1111/j.1600‐0501.2010.01974.x     

Biomechanical and Bone Histomorphological Evaluation of Two Surfaces on Tapered and Cylindrical Root Form Implants: An Experimental Study in Dogs

Purpose: The aim of this study was to evaluate the early bone response of tapered and cylindrical root form implants with two different surface treatments in fresh extraction sockets after 4 and 8 weeks. Materials and Methods: Surface treatments and implant design comprised (n = 9 each): tapered with dual acid‐etched surface; tapered with dual acid‐etched and sandblasted surface (T DAE SB); cylindrical with dual acid‐etched surface (C DAE); and cylindrical with dual acid‐etched and sandblasted surface (C DAE SB). Implants were placed in the distal sockets of mandibular premolars (₂P_2,3P_3,4P₄) of six beagle dogs, remaining in vivo for 4 and 8 weeks. After sacrifice, the implants were subjected to torque to the point of interface fracture and subsequently nondecalcified for histomorphological study. Statistical analysis was performed by a General Linear Model (GLM) analysis of variance model with a significance level of 5%. Results: Torque to interface fracture was significantly greater for the C DAE SB group than for the other groups (p < .001). Histomorphological analysis showed woven bone formation around all implant surfaces at 4 weeks and its replacement by lamellar bone at 8 weeks. Study time (4 or 8 weeks) did not affect torque measures. Conclusions: The double acid‐etched and sandblasted sample surface increased early bone biomechanical fixation of both cylindrical and tapered root form implants. The cylindrical root form implants showed higher torque to interface fracture values when compared with the tapered root form implants. The C DAE SB surface group showed the highest biomechanical fixation values (p < .001).     

3D打印和CAD/CAM氧化锆种植体骨结合性能的动物实验评价

目的 比较3D打印和计算机辅助设计与制造(CAD/CAM)氧化锆种植体与纯钛种植体在动物体内的骨结合和成骨效果的差异,评价氧化锆种植体骨结合性能.方法 分别将3D打印氧化锆、CAD/CAM种植体和钛种植体各20枚随机植入6只Beagle犬的胫骨内,8周后观察氧化锆种植体的成功率和骨结合能力,并与钛种植体进行比较,观察指...     

Histomorphometric analysis of the osseointegration of four different implant surfaces in the femoral epiphyses of rabbits

Objectives: The surface properties of titanium dental implants are key parameters for rapid and intimate bone–implant contact. The osseointegration of four implant surfaces was studied in the femoral epiphyses of rabbits. Material and methods: Titanium implants were either grit‐blasted with alumina or biphasic calcium phosphate (BCP) ceramic particles, coated with a thin octacalcium phosphate (OCP) layer, or prepared by large‐grit sand blasting and acid‐etched (SLA). After 2 and 8 weeks of implantation, the bone‐implant contact and bone growth inside the chambers were compared. Scanning electron microscopy (SEM) and profilometry showed distinct microtopographies. Results: The alumina‐Ti, BCP‐Ti and OCP‐Ti groups had similar average surface roughness in the 1–2 μm range whereas the SLA surface was significantly higher with a roughness averaging 4.5 μm. Concerning the osseointegration, the study demonstrated a significantly greater bone‐to‐implant contact for both the SLA and OCP‐Ti surfaces as compared with the grit‐blasted surfaces, alumina‐ and BCP‐Ti at both 2 and 8 weeks of healing. Conclusion: In this animal model, a biomimetic calcium phosphate coating gave similar osseointegration to the SLA surface. This biomimetic coating method may enhance the apposition of bone onto titanium dental implants.     

Comparing the effect of strontium‐functionalized and fluoride‐modified surfaces on early osseointegration

1 Background

Studies have shown that medical devices comprising strontium contribute to bone healing and osseointegration. The aim of this study was to evaluate the in vivo performance of surface‐functionalized implants (Ti‐Sr‐O) showing predictable release characteristics of strontium and compare it to performance a commercially available fluoride‐modified surface.

2 Methods

Ti‐Sr‐O functionalized, fluoride‐modified,  Grade 4 titanium implants were inserted in the femoral condyle of adult male New Zealand white rabbits. Atomic absorption spectrometry (AAS) was utilized to monitor strontium blood serum levels. Two weeks after insertion, histomorphometric evaluation was performed with respect to bone‐to‐implant contact (BIC%) and bone formation (BF%) using defined regions of interest.

3 Results

Mean values for BIC% showed a comparable degree of osseointegration for Ti‐Sr‐O and the fluoride‐modified surface, while BF% revealed a significant difference in increased BF with Ti‐Sr‐O. AAS measurements did not indicate any influence of the Ti‐Sr‐O modified implants on the strontium blood serum concentrations.

4 Conclusions

Within the limitations of this study, it was shown that the Ti‐Sr‐O coating, with sustained release characteristics of strontium, enhanced bone apposition and, thus, could find practical applications, e.g., within the field of medical implantology.     

Effect of surface contamination on osseointegration of dental implants surrounded by circumferential bone defects

Objective: This study was designed to evaluate the effect of surface contamination on osseointegration of dental implants surrounded by a circumferential bone defect and to compare osseointegration around Osseotite® with that around Nanotite^? implants. Materials and methods: The premolars on both sides of the mandible in four beagle dogs were extracted. Following 4 months healing, two Nanotite^? implants and two Osseotite® implants were partially inserted in the left side of each mandible. Some threads protruded from the tissues into the oral cavity. Following a 5 week healing period, the implants were removed and the contaminated part of each implant was cleaned. They were then installed to the full implant length on the contra lateral side of the mandibles. The coronal 5 mm of each implant was surrounded by 1 mm circumferential bone defect. Following 12 weeks of healing period, the dogs were sacrificed and biopsies were obtained. Ground sections were prepared for histomorphometric analysis. Results: All implants were associated with direct bone‐to‐implant contact on the portion of the implant surface contaminated previously and surrounded by bone defect. Nanotite^? implants performed better than Osseotite® implants. Conclusions: The results demonstrated that implant surfaces, which were contaminated previously and were surrounded by bone defects, can osseointegrate. To cite this article:
Mohamed S, Polyzois I, Renvert S, Claffey N. Effect of surface contamination on osseointegration of dental implants surrounded by circumferential bone defects. Clin. Oral Impl. Res. 21 , 2010; 513–519.
doi: 10.1111/j.1600‐0501.2010.01913.x     

紫外线光功能化对二氧化钛纳米管表面改性钛种植体骨结合的影响

目的 研究紫外线光功能化对二氧化纳米管钛表面改性钛种植体骨结合的影响。方法 采用预阳极氧化法制备二氧化钛（TiO₂）纳米管表面改性钛种植体，并用波长为250 nm、功率为2mW/cm²紫外线（UVA）对种植体进行处理。将种植体植入SD大鼠股骨，12周后取含种植体骨组织制作组织切片，通过显微镜观察种植体周围骨组织形成情况并计算骨结合率。结果UVA处理组种植体周围新生骨组织多于未UVA处理组，且更致密。UVA处理组和未UVA处理组的骨结合率分别为（72.21±10.42）%和（44.98±9.62）%，两组之间的差异具有统计学意义（P<.05）。结论UVA光功能化TiO₂纳米管表面改性有助于促进钛种植体骨结合。     

Bone tissue response to plasma-nitrided titanium implant surfaces

A current goal of dental implant research is the development of titanium (Ti) surfaces to improve osseointegration. Plasma nitriding treatments generate surfaces that favor osteoblast differentiation, a key event to the process of osteogenesis. Based on this, it is possible to hypothesize that plasma-nitrided Ti implants may positively impact osseointegration.

Objective

The aim of this study was to evaluate the in vivo bone response to Ti surfaces modified by plasma-nitriding treatments.

Material and Methods

Surface treatments consisted of 20% N₂ and 80% H₂, 450°C and 1.5 mbar during 1 h for planar and 3 h for hollow cathode. Untreated surface was used as control. Ten implants of each surface were placed into rabbit tibiae and 6 weeks post-implantation they were harvested for histological and histomorphometric analyses.

Results

Bone formation was observed in contact with all implants without statistically significant differences among the evaluated surfaces in terms of bone-to-implant contact, bone area between threads, and bone area within the mirror area.

Conclusion

Our results indicate that plasma nitriding treatments generate Ti implants that induce similar bone response to the untreated ones. Thus, as these treatments improve the physico-chemical properties of Ti without affecting its biocompatibility, they could be combined with modifications that favor bone formation in order to develop new implant surfaces.     

Histomorphometric Evaluation of Bioceramic Molecular Impregnated and Dual Acid‐Etched Implant Surfaces in the Human Posterior Maxilla

Background: Physical and bioceramic incorporation surface treatments at the nanometer scale showed higher means of bone‐to‐implant contact (BIC) and torque values compared with surface topography at the micrometer scale; however, the literature concerning the effect of nanometer scale parameters is sparse. Purpose: The aim of this study was to evaluate the influence of two different implant surfaces on the percentage bone‐to‐implant contact (BIC%) and bone osteocyte density in the human posterior maxilla after 2 months of unloaded healing. Materials and Methods: The implants utilized presented dual acid‐etched (DAE) surface and a bioceramic molecular impregnated treatment (Ossean®, Intra‐Lock International, Boca Raton, FL, USA) serving as control and test, respectively. Ten subjects (59 ± 9 years of age) received two implants (one of each surface) during conventional implant surgery in the posterior maxilla. After the non‐loaded period of 2 months, the implants and the surrounding tissue were removed by means of a trephine and were non‐decalcified processed for ground sectioning and analysis of BIC%, bone density in threaded area (BA%), and osteocyte index (Oi). Results: Two DAE implants were found to be clinically unstable at time of retrieval. Histometric evaluation showed significantly higher BIC% and Oi for the test compared to the control surface (p < .05), and that BA% was not significantly different between groups. Wilcoxon matched pairs test was used to compare the differences of histomorphometric variables between implant surfaces. The significance test was conducted at a 5% level of significance. Conclusion: The histological data suggest that the bioceramic molecular impregnated surface‐treated implants positively modulated bone healing at early implantation times compared to the DAE surface.