Early and immediate loading of titanium implants with fluoride-modified surfaces: results of 5-year prospective study

Objective: Multiple experimental and animal studies have shown that topographic, mechanical and chemical properties of implant surfaces lead to in vivo responses such as increased bone formation, increased bone anchorage and reduced healing time. A fluoride modification of the titanium implant surface also seems to positively influence bone anchorage as compared with unmodified titanium implants. Using implant survival and marginal bone loss as primary outcome parameters, the purpose of the present prospective study was to investigate whether a fluoride modification of the titanium implant surface has positive clinical effects. Materials and methods: The 17 patients included in this study received 49 Astra Tech OsseoSpeed^? implants for various indications in the maxilla and mandible. Implants were either loaded immediately or after a mean healing period of 9.56 weeks. Fifteen patients were followed up clinically including radiographic examination for 5 years. Forty‐two implants were assessed for implant survival, marginal bone loss, surgical and/or prosthetic complications, presence or absence of plaque, signs of inflammation and size of the papilla. Results: Of the original 17 patients, 15 patients were available for the full 60‐month follow‐up. One early implant failure occurred, leading to an implant survival rate of 97%. Radiographic analyses demonstrated stable bone conditions with a mean marginal bone loss of 0.1 mm (SD 0.4 mm, min ?0.7 mm, max 1.7 mm) after 5 years of function. Immediately loaded implants did not show a different mean marginal bone loss as compared with implants that were not loaded immediately. Repeated soft‐tissue examinations revealed healthy conditions in terms of 6.1% plaque and 4.2% of the implants with signs of inflammation at the 5‐year control. Discussion: Implants used in this study had high survival and success rates after 5 years. Marginal bone was well maintained, irrespective of the loading regime. To cite this article:
Mertens C, Steveling HG. Early and immediate loading of titanium implants with fluoride‐modified surfaces: results of 5‐year prospective study.
Clin. Oral Impl. Res. xx , 2011; 000–000.     

氟化物修饰种植体即刻负重的研究进展

传统的种植修复治疗方案因治疗周期较长且需多次手术而越来越难以获得患者的满意,如何缩短治疗周期并简化手术方案成为学者研究的方向;氟化物修饰种植体表面因其促进种植体早期骨愈合的特性而获得越来越多的应用。本文对近年来有关氟化物修饰种植体即刻负重的研究作一综述。     

Effects of fluoride-modified titanium surfaces on osteoblast proliferation and gene expression

PURPOSE: The objective of this study was to test the hypothesis that fluoride-modified titanium surfaces would enhance osteoblast differentiation. Osteoblast growth on a moderately rough etched fluoride-modified titanium surface (alteration in cellular differentiation) was compared to osteoblast growth on the same surface grit-blasted with titanium dioxide. The potential role of nanometer-level alterations on cell shape and subsequent differentiation was then compared. MATERIALS AND METHODS: Human embryonic palatal mesenchymal (HEPM) cultures were incubated on the respective surfaces for 1, 3, and 7 days, followed by analysis for cell proliferation, alkaline phosphatase (ALP) -specific activity, and mRNA steady-state expression for bone-related genes (ALP, type I collagen, osteocalcin, bone sialoprotein [BSP] II, Cbfa1, and osterix) by real-time polymerase chain reaction (PCR). RESULTS: The different surfaces did not alter the mRNA expression for ALP, type I collagen, osterix, osteocalcin, or BSP II. However, Cbfa1 expression on the fluoride-modified titanium surface was significantly higher (P < .001) at 1 week. The number of cells on this surface was 20% lower than the number of cells on the surface TiO2-blasted with 25-microm particles but not significantly different from the number of cells on the surface TiO2-blasted with 125-microm particles. Cells grown on all the titanium surfaces expressed similar levels of ALP activity. CONCLUSIONS: The results indicated that a fluoride-modified surface topography, in synergy with surface roughness, may have a greater influence on the level of expression of Cbfa1 (a key regulator for osteogenesis) than the unmodified titanium surfaces studied.     

Bone healing at implants with a fluoride-modified surface: an experimental study in dogs

OBJECTIVES: The aim of the present experiment was to study early stages of osseointegration to implants with a fluoride-modified surface. MATERIAL AND METHODS: Six mongrel dogs, about 1-year old, were used. All mandibular premolars and the first mandibular molars were extracted. Three months later, mucoperiosteal flaps were elevated in one side of the mandible and six sites were identified for implant placement. The control implants (MicroThread) had a TiOblast surface, while the test implants (OsseoSpeed) had a fluoride-modified TiOblast surface. Both types of implants had a similar geometry, a diameter of 3.5 mm and were 8 mm long. Following installation, cover screws were placed and the flaps were adjusted and sutured to cover all implants. Four weeks after the first implant surgery, the installation procedure was repeated in the opposite side of the mandible. Two weeks later, biopsies were obtained and prepared for histological analysis. The void that occurred between the cut bone wall of the recipient site and the macro-threads of the implant immediately following implant installation was used to study early bone formation. RESULTS: It was demonstrated that the amount of new bone that formed in the voids within the first 2 weeks of healing was larger at fluoride-modified implants (test) than at TiOblast (control) implants. It was further observed that the amount of bone-to-implant contact that had been established after 2 weeks in the macro-threaded portion of the implant was significantly larger at the test implants than at the controls. CONCLUSION: It is suggested that the fluoride-modified implant surface promotes osseointegration in the early phase of healing following implant installation.     

A 2-year prospective study on immediate loading with fluoride-modified implants in the edentulous mandible

Objectives: Chemically modified surfaces were introduced during the last decade to improve indications for implant treatment. The fluoride‐modified implant (Osseospeed^®) was launched in 2004 and clinical studies suggest a more rapid bone formation and stronger bone to implant contact. However, limited clinical data are available on marginal bone loss and the outcome after >1 year under immediate loading conditions is not fully understood. Hence, the purpose of this prospective study was to present implant survival and marginal bone level data when fluoride‐modified implants are supporting a fully functional rehabilitation from the day after surgery in the completely edentulous mandible. Materials and methods: Twenty‐five patients, completely edentulous in the mandible, were consecutively treated with five fluoride‐modified implants that were functionally loaded with a provisional screw retained restoration. Marginal bone loss was measured from day of surgery to 3, 6, 12 and 24 months. Implants were considered successful after 24 months if radiographic bone loss did not exceed 1 mm and no pain or mobility was caused under a torque of 20 N cm. Statistical analysis was carried out on both patient and implant levels. Results: All implants survived and mean bone loss on implant level after 3, 6, 12 and 24 months was 0.14, 0.13, 0.11 and 0.11 mm, respectively. Bone loss was only statistically significant between baseline and 3 months (P<0.001) and remained unchanged afterward. None of the implants lost >1 mm of bone after 2 years. On the patient level, the mean bone loss after 2 years was 0.12 mm (SD 0.14; range ?0.06 to 0.55) with probing pocket depth 2.45 mm (SD 0.43; range 1.3–3.1) and bleeding index 0.55% (SD 0.34; range 0–1). Conclusion: Immediate loading of fluoride‐modified implants is a predictable treatment yielding a high survival and success rate after 2 years. To cite this article:
Collaert B, Wijnen L, De Bruyn H. A 2‐year prospective study on immediate loading with fluoride‐modified implants in the edentulous mandible.
Clin. Oral Impl. Res. 22 , 2011; 1111–1116.
doi: 10.1111/j.1600‐0501.2010.02077.x     

Bone-implant contact at calcium phosphate-coated and porous titanium oxide (TiUnite)-modified oral implants

BACKGROUND: Calcium phosphate (CP)-coated implants are usually referred to as having osteoconductive properties, whereas titanium implants with a native oxide layer are considered less osteoconductive. Often smooth titanium oxides (TOs) are compared to relatively rough CP structures. The objective of this study was to evaluate osteoconduction by comparing bone-implant contact at a relatively smooth, highly crystalline CP coating with a structured, porous TO (TiUnite)-modified surface. MATERIAL AND METHODS: Ten adult Hound Labrador mongrel dogs were used. Four titanium implants (Nobel Biocare) with CP-coated (2) or TO-modified (2) surfaces were installed 12 weeks following mandibular premolar and molar teeth extraction. The implants were alternated within and between jaw quadrants in consecutive animals. Mucosal flaps were advanced and sutured leaving the implants in a submerged position. The animals were injected with fluorescent bone labels at 3 and 4 weeks postsurgery, and pre-euthanasia to monitor progress of bone formation. The animals were euthanized at 8 weeks postsurgery and block biopsies were prepared for histologic and histometric analysis. RESULTS: There were no remarkable differences in bone formation and apparent bone-implant contact comparing the TO-modified and CP-coated surfaces. However, the measured average bone-implant contact was 71% and 57% (P=0.027) for TO-modified and CP-coated implants, respectively. CONCLUSIONS: We conclude that the TO surface exhibits osteoconductive properties exceeding that of the CP surface. One or several of the chemical and physical properties of the TO surface may result in the remarkable bone formation along its surface. This study indicated that crystallinity and/or chemistry may be important.     

Healing at fluoride-modified implants placed in wide marginal defects: an experimental study in dogs

OBJECTIVE: To study the healing at fluoride-modified implants placed in wide circumferential defects. MATERIAL AND METHODS: Six mongrel dogs were used. The mandibular premolars and first molars were extracted. Three months later four implants were placed in one side of the mandible of each dog. The control implants (MicroThread) had a TiOblast surface, while the test implants (OsseoSpeed) had a fluoride-modified surface. Two implants of each type were placed. The marginal 50% of the prepared canal was widened using step drills. Following installation a 1 mm wide gap occurred between the implant surface and the bone wall in the defect. All implants were submerged. The installation procedure was repeated in the opposite side of the mandible 4 weeks after the first implant surgery. Two weeks later the animals were euthanized and block biopsies containing the implant and surrounding tissues were prepared for histological analysis. RESULTS: The histological analysis revealed that a significantly larger area of osseointegration was established within the defect at fluoride-modified implants than at implants with a TiOblast surface after 6 weeks of healing. Further, the degree of bone-to-implant contact within the defect area was larger at fluoride-modified implants than at the TiOblast implants. CONCLUSION: It is suggested that the fluoride-modified implant surface promotes bone formation and osseointegration.     

Correction of alveolar ridge deformities with titanium implants

A technique for the correction of alveolar ridge defects with titanium implants has been described. Custom cast titanium implants enable the dentist to achieve precise, predictable, stable ridge augmentation previously unavailable with other techniques and materials. The extension of this technique for the correction of more complex alveolar defects is logical.     

Dynamic sterilization of titanium implants with ultraviolet light

All implantable devices must be sterile. However, autoclaves produce poor surface properties that jeopardize the integration process. The application of a modified ultraviolet light source has proven to enhance bioreactivity by controlling surface properties, but it lacks validation of its sterilization capabilities. Forty-eight titanium implants were contaminated with spores of the biological indicator Bacillus stearothermophilus and subjected to "dynamic sterilization" by ultraviolet light. Forty-seven of the implants were successfully sterilized, as indicated by not producing turbidity in a suitable growth medium. This sterilization technique only requires a 20-second exposure to achieve sterility.     

Enamel matrix derivative and titanium implants

AIM: The aim of present study was to evaluate if an enamel matrix derivative (Emdogain) may enhance bone formation and osseointegration of titanium implants, using a well-documented rabbit model. MATERIAL AND METHODS: Thirty-six threaded commercially pure titanium (cp.ti.) implants were inserted in six New Zealand white rabbits. One implant was placed in each femur and two in each tibia. Prior to implant insertion approximately 0.5 mL of Emdogain (EMD) (test) or the vehicle gel (PGA: propylene glycol alginate) (control) was injected into the surgically prepared implant site. The follow-up time was 6 weeks. Biomechanical evaluations by resonance frequency analysis (RFA) and removal torque measurements (RTQ) were performed. Histomorphometrical quantifications were made on ground sections by measurements of the percentage of bone-to-metal contact, bone area inside the threads as well as outside the threads (mirror image). Bone lengths along the implant surface were also measured and used for shear strength calculations. RESULTS: The results demonstrated no beneficial effects from the EMD treatment on bone formation around titanium implants in any of the tested parameters. Significant differences were demonstrated with removal torque test and shear force calculations for the control implants. No other parameter demonstrated a statistically significant difference. CONCLUSION: The results of the present study may indicate that EMD does not contribute to bone formation around titanium implants. This observation may indicate that the bone formation that occurs after EMD treatment in periodontal defects is the result of functional adaptation. However, further research is required to evaluate the effect of EMD treatment on bone formation.     

Microbiologic diagnostics at titanium implants

Background: The microbiota found at periimplant lesions have been shown to contain putative periodontal pathogens as well as opportunistic species such as Staphylococcus spp, enterics, and Candida spp. Therefore, a microbiologic diagnosis may be of value as guidance before treatment of such lesions. Purpose: The aim of this study was to evaluate the prevalence of some putative pathogens associated with long‐term fol‐lowed‐up cases using two different microbiologic procedures. Malerials and Methods: Fifteen subjects contributed with plaque samples from teeth and implants; these were analyzed with respect to 18 putative periimplant pathogens using cultural methods and a deoxyribonucleic acid DNA‐DNA hybridization technique. Results: The number of individuals positive for the analyzed pathogens was similar in samples taken from teeth and implants when analyzed with the DNA‐DNA hybridization technique. When comparing detection frequency by culture procedure and by “checkerboard” technique at implants, the number of individuals positive for these species was lower with the traditional culture technique than with the checkerboard analyses. Using a higher cutoff point (4) with the checkerboard technique, the number of positive individuals was generally lower than that found with the culture technique. When comparing the techniques on an implant site level, the prevalence obtained by culture was lower for all analyzed species. If the specific species were present in the samples analyzed by the checkerboard technique, they were present only in every second sample analyzed with the culture technique. The high specificity values showed that if the checkerboard technique did not detect any Porphyromonas gingivalis, Prevotla intermedia, Actinobadllus actinomycetem‐comitans, or Fusobacterium nudeatum, the bacteria were also undetectable by the culture technique. The two methods therefore did not overlap but did supplement each other. Conclusions: Based on the current results it is recommended that the technique used when analyzing microbiota around titanium implants should be a combination of the two protocols mentioned as they seem to give the most comprehensive outcome when used together.     

Quantitative and qualitative investigations of surface enlarged titanium and titanium alloy implants

Screw shaped implants of commercially pure (c.p.) titanium and titanium-6aluminum-4vanadium (Ti₆AI₄V) were blasted with particles of TiO₂ of mean sizes of 25 μm (Group I) and 7.5 μm (Group II) and inserted in rabbit bone for 3 months. The surface roughness of the implants was examined and quantified with an optical scanning 3-dimensional instrument (TopScan 3D system), revealing the two alloy surfaces in each group had similar surface roughness. Biomechanical (removal torque) tests showed the c.p. titanium implants to be significantly more stable in the bone bed than those of Ti₆AI₄V. In Group I, the c.p titanium implants demonstrated a mean removal torque of 38 N cm while the Ti₆AI₄V demonstrated a mean removal torque of 27 Ncm (P=0.004). Group II implants revealed a mean removal torque of 70 Ncm for the c.p. ti and 50 Ncm for the alloy samples (P=0.003). The removal torque values were converted to shear forces/strengths by three calculation methods, based on (a) the entire length of the implant surface in the cortical region, (b) the thickness of the cortical bone measured in close vicinity to the thread peaks and *lpar;c) the bone-metal contact length measured on the non-unscrewed neighbouring implants. Group I: (a) the c.p. ti implants revealed a mean shear force of 4 vs a mean of 3 N/mm² for the alloy samples. Shear strengths based on (b); were 8 for c.p. ti vs 6 N/mm² for the alloy. The mean shear strength/force if calculated according to (c) revealed 23 for c.p. ti vs 18 N/mm² for the alloy. Corresponding numbers for Group II; (a) cp. ti 8 compared to 6 N/mm² for the alloy, (b) c.p. ti demonstrated a mean value of 17 vs 11 N/mm² for the alloy. According to method (c); c.p. ti had a mean shear strength of 26 vs 22 N/mm² for the alloy samples. Histomorphometrical comparisons were performed on 10 urn thick undecalcified ground sections in the light microscope. In both Group I and Group II, the calculations of the mean bone-to-metal contact demonstrated more bone in contact to the c-p. titanium implants than to the Ti₆AI₄V ones. Whereas comparisons of the bone volume inside the threads demonstrated slightly higher bone volumes around the alloy samples, no statistically significant difference was obtained between the two materials histomorphometrically.     

Osseointegration of 3D-printed titanium implants with surface and structure modifications

BackgroundThe purpose of this study was to establish a mechanical and histological basis for the development of biocompatible maxillofacial reconstruction implants by combining 3D-printed porous titanium structures and surface treatment. Improved osseointegration of 3D-printed titanium implants for reconstruction of maxillofacial segmental bone defect could be advantageous in not only quick osseointegration into the bone tissue but also in stabilizing the reconstruction.MethodsVarious macro-mesh titanium scaffolds were fabricated by 3D-printing. Human mesenchymal stem cells were used for cell attachment and proliferation assays. Osteogenic differentiation was confirmed by quantitative polymerase chain reaction analysis. The osseointegration rate was measured using micro computed tomography imaging and histological analysis.ResultsIn three dimensional-printed scaffold, globular microparticle shape was observed regardless of structure or surface modification. Cell attachment and proliferation rates increased according to the internal mesh structure and surface modification. However, osteogenic differentiation in vitro and osseointegration in vivo revealed that non-mesh structure/non-surface modified scaffolds showed the most appropriate treatment effect.Conclusion3D-printed solid structure is the most suitable option for maxillofacial reconstruction. Various mesh structures reduced osteogenesis of the mesenchymal stem cells and osseointegration compared with that by the solid structure. Surface modification by microarc oxidation induced cell proliferation and increased the expression of some osteogenic genes partially; however, most of the markers revealed that the non-anodized solid scaffold was the most suitable for maxillofacial reconstruction.     

Simvastatin promotes osteogenesis around titanium implants

OBJECTIVES: Hydroxymethylglutaryl-coenzyme A reductase inhibitors, the so-called statins, have been widely used for hyperlipidemic patients, and it was recently reported that it promoted bone formation. In the present study, we examined the effect of simvastatin on the promotion of osteogenesis around titanium implants. MATERIALS AND METHODS: Ten 30-week-old rats received pure titanium implants in both tibiae, and were then divided into experimental and control groups. The experimental group was administered simvastatin daily. Thirty days later, all animals were killed and then specimens were prepared. The bone contact ratio (BCR) to the implant and bone density (BD) around the implant, as well as histological findings, were obtained. RESULTS: In the control group, newly formed bone could be seen around the implants. It was seen to be in direct contact with the implant surface, but otherwise unmineralized connective tissue was occasionally interposed. In the medullary canal, a scanty amount of bone trabeculae was observed. In the experimental group, in contrast, thicker bone trabeculae were abundantly seen in the medullary canal and showed a mesh-like structure. In the histometrical observations, both BCR and BD of the experimental group were significantly greater than those of the control group. CONCLUSION: The administration of simvastatin increases the value of both BCR and BD. This drug may have the potential to improve the nature of osseointegration.